Effect of wheat bran on gluten network formation as studied through dough development, dough rheology and bread microstructure.

Transcription

1 Effect of whet brn on gluten network formtion s studied through dough development, dough rheology nd bred microstructure by Hym Gjul B.Tech., Osmni University, Indi, 2003 M.S., Knss Stte University, 2007 AN ABSTRACT OF A DISSERTATION submitted in prtil fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY Deprtment of Grin Science nd Industry College of Agriculture KANSAS STATE UNIVERSITY Mnhttn, Knss 2017

2 Abstrct The overll hypothesis underlying this study is tht the nture nd extent of brn interctions with the gluten protein mtrix ply dominnt role in both 'in-process' dough nd finl product qulity of whole grin bked goods. Therefore, the purposeful mnipultion of those interctions should be ble to minimize dverse processing or product chrcteristics resulting from brn inclusion/presence. The pproch we took ws to study the effects of brn milled to different prticle sizes on dough development during nd fter dough mixing using fundmentl rheology combined with trditionl cerel chemistry pproches nd x-ry microtomogrphy (XMT). The reserch outcomes were used to crete better picture of how the brn is effecting the dough development nd to suggest strtegies tht llow for the control of tht effect. Study-I focused on chrcteriztion of the chemicl properties, empiricl rheologicl properties nd bking performnce of flours nd dough with different brn contents from different sources. The development of dough microstructure nd the resulting crumb texture in the presence of different brn were studied using XMT. HRW nd SW brn dditions resulted in higher wter bsorptions (WA) irrespective of the flour type nd brn source. Fine brn cused slightly higher WA followed by corse nd s is brn. Both HRW nd SW brn decresed the dough stbility of HRW flour, while it improved the stbility of SW flour doughs. Mcro nd microstructure of bked products were significntly ffected both brn type nd ddition level. HRW brn dded to HRW flour resulted in 8-23% decrese in lof volume while SW brn dded t the sme level cused 3-11% decrese. XMT indicted tht brn decresed the totl number of ir cells significntly. SW flour resulted in hrder crumb texture thn tht of HRW flour breds. Overll, SW brn hd less detrimentl effects on mixing nd bking performnce of HRW flour. Study-II focused on specific brn prticle size nd composition on smll nd lrge deformtion behvior of strong nd wek flour doughs. Smll deformtion behvior ws chrcterized using frequency nd temperture sweep tests, while the lrge deformtion behvior ws studied using creep recovery nd unixil extensionl testing. The results reveled tht the rheologicl behvior of brn-enriched doughs depend on type of bse flour, brn type, brn replcement level (0, 5, 10%), nd the dough development protocol. Wek flour doughs

3 benefited from inclusion of brn s inherently low pek height nd stbility of these doughs improved in the presence of brn. Temperture sweeps indicted slight decrese in G nd G" until round C. In the sme temperture rnge, presence of brn incresed the moduli of composite four compred to tht of the control flours. Creep complince prmeters indicted tht both brn source nd brn replcement hd significnt effect on mximum complince (Jmx) nd elstic complince (Je). Finlly, the brn type ffected unixil extensionl properties, mximum resistnce (Rmx) nd elsticity (E), significntly independent from the type of bse flour.

4 Effect of whet brn on gluten network formtion s studied through dough development, dough rheology nd bred microstructure by Hym Gjul B.Tech., Osmni University, Indi, 2003 M.S., Knss Stte University, 2007 A DISSERTATION submitted in prtil fulfillment of the requirements for the degree DOCTOR OF PHILOSOPHY Deprtment of Grin Science nd Industry College of Agriculture KANSAS STATE UNIVERSITY Mnhttn, Knss 2017 Approved by: Co-Mjor Professor Huly Dogn Approved by: Co-Mjor Professor Jon Fubion

5 Copyright Hym Gjul 2017.

6 Abstrct The overll hypothesis underlying this study is tht the nture nd extent of brn interctions with the gluten protein mtrix ply dominnt role in both 'in-process' dough nd finl product qulity of whole grin bked goods. Therefore, the purposeful mnipultion of those interctions should be ble to minimize dverse processing or product chrcteristics resulting from brn inclusion/presence. The pproch we took ws to study the effects of brn milled to different prticle sizes on dough development during nd fter dough mixing using fundmentl rheology combined with trditionl cerel chemistry pproches nd x-ry microtomogrphy (XMT). The reserch outcomes were used to crete better picture of how the brn is effecting the dough development nd to suggest strtegies tht llow for the control of tht effect. Study-I focused on chrcteriztion of the chemicl properties, empiricl rheologicl properties nd bking performnce of flours nd dough with different brn contents from different sources. The development of dough microstructure nd the resulting crumb texture in the presence of different brn were studied using XMT. HRW nd SW brn dditions resulted in higher wter bsorptions (WA) irrespective of the flour type nd brn source. Fine brn cused slightly higher WA followed by corse nd s is brn. Both HRW nd SW brn decresed the dough stbility of HRW flour, while it improved the stbility of SW flour doughs. Mcro nd microstructure of bked products were significntly ffected both brn type nd ddition level. HRW brn dded to HRW flour resulted in 8-23% decrese in lof volume while SW brn dded t the sme level cused 3-11% decrese. XMT indicted tht brn decresed the totl number of ir cells significntly. SW flour resulted in hrder crumb texture thn tht of HRW flour breds. Overll, SW brn hd less detrimentl effects on mixing nd bking performnce of HRW flour. Study-II focused on specific brn prticle size nd composition on smll nd lrge deformtion behvior of strong nd wek flour doughs. Smll deformtion behvior ws chrcterized using frequency nd temperture sweep tests, while the lrge deformtion behvior ws studied using creep recovery nd unixil extensionl testing. The results reveled tht the rheologicl behvior of brn-enriched doughs depend on type of bse flour, brn type, brn replcement level (0, 5, 10%), nd the dough development protocol. Wek flour doughs

7 benefited from inclusion of brn s inherently low pek height nd stbility of these doughs improved in the presence of brn. Temperture sweeps indicted slight decrese in G nd G" until round C. In the sme temperture rnge, presence of brn incresed the moduli of composite four compred to tht of the control flours. Creep complince prmeters indicted tht both brn source nd brn replcement hd significnt effect on mximum complince (Jmx) nd elstic complince (Je). Finlly, the brn type ffected unixil extensionl properties, mximum resistnce (Rmx) nd elsticity (E), significntly independent from the type of bse flour.

8 Tble of Contents List of Figures... xii List of Tbles... xv Acknowledgements... xvi Dediction... xviii Chpter 1 - Bckground nd Gols Bred-mking Fiber nd Its Helth Benefits Fiber-enriched Foods: Impct on the Industry Dietry Fiber in Bked Products Whet Brn Whet Brn in Bred-mking Technologicl Chllenges-Brn in Bked Goods Interction with Wter Physicl Hindrnce nd Disruption Effect Previous Studies Physicl nd Structurl Properties of Dough Systems Rheologicl Properties Hypothesis Scope nd Approch References Chpter 2 - Effects of hrd nd soft whet brns t vrying size nd inclusion levels on dough development nd crumb structure nd texture of the end products Abstrct Introduction Mterils nd Methods Mterils Chemicl Composition Wter Sorption Behvior Mixing nd Psting Behvior viii

9 Frinogrph Mixogrph MixoLb Test Bking Bred Mcrostructure Bred Microstructure Texture Profile Anlysis (TPA) Sttisticl Anlysis Results nd Discussion Composition nd Wter Absorption Behvior Dough Mixing Properties Mixing nd Psting Properties Bred Mcrostructure Bred Microstructure Bred Texture Qulity Conclusions Acknowledgements References Chpter 3 - Effect of brn frctions of vrying ntomicl origin nd size t vrying replcement levels on dough development, nd smll nd lrge deformtion rheologicl properties Abstrct Introduction Mterils nd Methods Whet Flour nd Brn Experimentl Design Brn nd Flour Chrcteriztion Proximte Anlysis of Flours nd Brn Sub-frctions Solvent Retention Cpcity Prticle Size Dough Development Frinogrph ix

10 Mixogrph Dough Rheology (Smll Deformtion) Smple Preprtion Stress Sweep (Liner Viscoelstic Region) Frequency Sweep Temperture Sweep Dough Rheology (Lrge Deformtion) Unixil Extensionl Properties Creep Recovery Stress Relxtion Sttisticl Anlysis Results nd Discussion Physicl nd Chemicl Properties of Bse mterils Proximte Anlysis Solvent Retention Cpcity (SRC) of the Brn Frctions Solvent Retention Cpcity (SRC) of the Composite Flours Dough Development Mixogrph Frinogrph Dough Rheology Smll Deformtion Behvior Stress Sweeps (Liner Viscoelstic Region) Frequency Sweeps Temperture Sweeps Lrge Deformtion Behvior Creep nd Recovery Unixil Extensionl Properties Stress Relxtion Conclusions Acknowledgements References x

11 Chpter 4 - Conclusions nd Future Work Reserch Summry Limittions Future Work References xi

12 List of Figures Figure 1.1 The seven lyers constituting of whet brn (dpted from Frdet 2010)... 7 Figure 2.1 Dough development properties of Hrd Red Winter (HRW) nd Soft White (SW) flour doughs in the presence of brn. () Wter bsorption, (b) dough development time, (c) stbility Figure 2.2 Mcrostructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in the presence of brn. () Lof volume, (b) totl number of cells, (c) cell size, (d) cell wll thickness Figure 2.3 Microstructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in the presence of brn. () Air cell size distribution, (b) cell wll thickness distribution Figure 2.4 Microstructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in presence of brn. () Void volume, (b) verge cell size, (c) verge cell wll thickness Figure 2.5 Texture Profile Anlysis (TPA) hrdness of Hrd Red Winter (HRW) nd Soft White (SW) in the presence of brn Figure 3.1 Prticle size distribution of the brn smples Figure 3.2 Solvent retention cpcity (SRC) of strong (S) flour nd brn smples. () Wter SRC, (b) Sucrose SRC, (c) Sodium crbonte SRC, (d) Lctic cid SRC Figure 3.3 Solvent retention cpcity (SRC) of strong (S) flour t 5 nd 10% brn replcement levels. () Wter SRC, (b) Sucrose SRC, (c) Sodium crbonte SRC, (d) Lctic cid SRC Figure 3.4 Mixogrph prmeters of flour smples t 5 nd 10% brn replcement levels t constnt wter bsorption. () Pek time, strong (S) flour, (b) Pek height, strong (S) flour, (c) Pek time, wek (W) flour, (d) Pek height, wek (W) flour Figure 3.5 Mixogrph prmeters of flour smples t 5 nd 10% brn replcement levels t optimum wter bsorption. () Pek time, strong (S) flour, (b) Pek height, strong (S) flour, (c) Pek time, wek (W) flour, (d) Pek height, wek (W) flour Figure 3.6 Frinogrph prmeters of flour smples t 5 nd 10% brn replcement levels. () Wter bsorption, strong (S) flour, (b) Wter bsorption, wek (W) flour, (c) Development xii

13 time, strong (S) flour, (d) Development time, wek (W) flour, (e) Stbility, strong (S) flour, (f) Stbility, wek (W) flour Figure 3.7 Storge modulus (G ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption Figure 3.8 Storge modulus (G ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.9 Loss modulus (Gʺ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption Figure 3.10 Loss modulus (Gʺ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.11 Storge (G ) nd loss (G ) moduli t 1 Hz frequency. () G of strong (S) flour, (b) G of strong (S) flour, (c) G of wek (W) flour, nd (d) G of wek (W) flour t 5 nd 10% brn replcement levels t constnt wter bsorption Figure 3.12 Storge (G ) nd loss (Gʺ) moduli t 1 Hz frequency. () G of strong (S) flour, (b) G of strong (S) flour, (c) G of wek (W) flour, nd (d) G of wek (W) flour t 5 nd 10% brn replcement levels t optimum wter bsorption Figure 3.13 Tngent delt ( ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption Figure 3.14 Tngent delt ( ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.15 Complex viscosity ( *) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption xiii

14 Figure 3.16 Complex viscosity ( *) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.17 Storge modulus (G ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.18 Loss modulus (Gʺ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.19 Tngent delt ( ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.20 Complex viscosity ( *) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption Figure 3.21 Creep nd recovery profiles of strong nd wek flours t 5 nd 10% brn replcement levels t optimum wter bsorption. () Strong (S) flour, ctegory-i brns, (b) Strong (S) flour, ctegory-ii brns, (c) Wek (W) flour, ctegory-i brns, (d) Wek (W) flour, ctegory-ii brns Figure 3.22 Unixil extensionl properties. () Rmx of strong (S) flour, (b) E of strong (S) flour, (c) Rmx of wek (W) flour, (d) E of wek (W) flour t 5 nd 10% brn replcement levels t constnt wter bsorption Figure 3.23 Unixil extensionl properties. () Rmx of strong (S) flour, (b) E of strong (S) flour, (c) Rmx of wek (W) flour, (d) E of wek (W) flour t 5 nd 10% brn replcement levels t optimum wter bsorption xiv

15 List of Tbles Tble 1.1 Clssifictions of fiber enriched breds (dpted from Dubois 1978)... 4 Tble 1.2 Mjor helth benefits of bioctive compound found in whole-grin cerel (dpted from Frdet et l 2010)... 6 Tble 2.1Compositionl nlysis of HRW nd SW Flour nd brn Tble 2.2 MixoLb mixing nd psting profile prmeters of Hrd Red Winter (HRW) nd Soft White (SW) flour doughs in the presence of brn Tble 3.1 Properties of flour smples Tble 3.2 Clssifiction of the brn smples Tble 3.3 Physico-chemicl properties of brn smples Tble 3.4 Slope of storge (G ) nd loss (G ) moduli versus frequency curves of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement level t constnt wter bsorption Tble 3.5 Slope of storge (G ) nd loss (G ) moduli versus frequency curves of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement t optimum wter bsorption Tble 3.6 Pek storge (G ) nd loss (G ) moduli, temperture t which pek G ws ttined (TG mx) nd pek viscosity ( *) of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement level t optimum wter bsorption Tble 3.7 Creep nd recovery prmeters of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement t optimum wter bsorption Tble 3.8 Anlysis of Vrince (ANOVA) Tukey test results xv

16 Acknowledgements Firstly, in the most dedicted mnner, I bow with extreme regrds to Almighty God for mking me cpble of completing my Ph.D. Disserttion. I express my sincere grtitude nd pprecition to my mjor dvisors Dr. Huly Dogn nd Dr. Jon Fubion who were more thn generous with their expertise nd precious time. A specil thnks to Dr. Huly Dogn for her countless hours of intellectul guidnce, encourgement nd most of ll ptience throughout the entire process of my doctorl progrm. I m much indebted to them for their inspiring guidnce, ffection, meticulous suggestions nd stute criticism throughout my reserch work. I m grteful to my committee member, Dr. Sjid Alvi, for his continuous support nd his criticl suggestions nd dvice when it is needed. My sincere thnks extend to committee members, Dr. Yong Cheng Shi, Dr. Fdi Armouni nd my outside chirperson Dr. Kdri Koppel for their vluble suggestions nd comments tht led to significnt improvement in my reserch. I m eternlly grteful for the questions nswered nd guidnce provided by Lte Dr. Chuck Wlker. Hertfelt thnks re due to Dr. Becky Miller t the Whet Qulity Lb for her ssistnce, use of her equipment nd guidnce for my reserch study. Much pprecition goes to Dr. Jyendr Ammchrl nd his students of the Dept. of Animl Sciences nd Industry t Knss Stte University for llowing the use of Rheometer, Dr. Jeff Wilson nd Ms. Hien Vu t USDA-ARS, Center for Grin nd Animl Helth Reserch (CGAHR), Mnhttn, KS, for helping in use the Prticle Size Anlyzer. I wish to extend my thnks to Mr. Dve Krishock nd Mr. Michel Moore of the Bkery Science progrm; Dr. Jeff Gwirtz nd the lte Mr. Ron Stevenson of the Grin Science nd Industry s Milling lbortory; Mr. Quinten Allen nd Mr. Shwn Thiele for their ssistnce in collecting the whet brn t the Hll Ross Flour Mill. A specil thnks to Mrs. Beverly McGee, Mrs. Liz Svge nd ll stff members, for being there to help nd ssist on nything or everything needed for reserch nd shring words of encourgement nd support. xvi

17 The reserch study ws supported by USDA-NRI grnt nd I m very thnkful to C.W. Brbender Instruments, Inc. for the Fellowship Awrd. I m grteful to their contributions nd generosity to the fellowship, which hs covered my tuition nd living expenses. I would like to thnk my fellow grdute students - Moses Khmis, Pul Mitchell, Ki Honey, Yingnn Zho, Dr. George Twil, Myr Perez Fjrdo for their friendship, countless hours of lughter, nd support. Much pprecition nd specil thnks to ll my pst nd present reserch group members for their support nd help. I will lwys remember the unforgettble time spent with my collegues nd friends t K-Stte for shring their experiences nd encourgement. Much pprecition goes to Indu Seethrmn nd her fmily, Nz Ysmin, Pvn Mneplli, Shrmil Vegesn, Poojith Bikki, Sneh Gullplli nd Srvni Donepudi for ll the mels, the lughter, nd ll the memories during my lst phse of sty t K-Stte. I would like to thnk friends Mnohr Jsty, Rnjith Krminll nd his fmily from Brtlesville for their support to my husbnd Kirn Bndru nd lovely dughter Any Bndru during my bsence. I would like to thnk specilly my sisters Rm Bongni, Um Gjul, Sirish Gjul, nd my friend Sujth Ngulplly for their incessnt help nd support, especilly through the hrd times. Mny thnks to my whole extended fmily including brother in-lws, sister in-lws, nephews nd nieces for their encourgement nd support system. Most importntly, I would like to thnk my prents, Synn Gjul nd Anusuy Gjul, for believing in me nd giving unconditionl love nd support throughout my life. My sincere thnks nd pprecition to my fther in-lw, Shnkrih Bndru nd mother in-lw, Lkshmi Bndru for their unconditionl encourgement, cre nd love kept me inspired during my grdute work. Finlly, I would like to thnk nd indebted to my husbnd, Kirn Bndru nd my drling dughter, Any Bndru for being my pillrs of strength nd cheerleders throughout my grdute progrm. Their love, ffection nd blessings hve me where I m tody. xvii

18 Dediction To my der husbnd, Kirn Bndru nd loving dughter, Any Bndru. Shring our life nd love long this journey together is blessing beyond words. You both kept me motivted nd inspired me throughout the doctorte progrm. Thnk you both for lwys being with me. xviii

19 Chpter 1 - Bckground nd Gols 1.1 Bred-mking Whet flour with high protein qulity is used for wide rnge of bked products especilly bred due to the unique viscoelstic properties of the dough. Whet contins the gluten forming proteins which forms viscoelstic dough. By forming this viscoelstic dough, it llows the ir cell incorportion nd resists their colescence. This property of the dough is very importnt for bred mking nd production. The bred-mking process consists of series of stges including mixing, fermenttion, dividing, proofing nd bking. The chnges in the rheologicl properties of the dough in ech of these stges re the consequences of chnges in dough structure t both the moleculr nd microscopic levels. The mixing process involves mixing of flour nd other ingredients with wter nd hs significnt influence on finl product texture (Angioloni nd Ros 2005). The objective of mixing is to form nd develop the gluten network into viscoelstic dough, with the bility to retin incorported ir. The mixing energy input nd power re criticl in proper dough development nd creting tiny gs nuclei in the dough (Hnselmnn nd Windhb 1998). These gs nuclei serve s nucletion points for the diffusion of crbon dioxide, produced by yest during fermenttion. Four importnt fctors ffect the ir incorportion during mixing process; the gs content of the dough, the rte of turnover of gs during mixing, the distribution of gs in terms of the bubble size distribution, nd the gseous composition of the bubbles (Cmpbell 2003). These fctors re found to be dependent on the hedspce pressure pplied nd type of the mixer nd blde design used in the mixing process (Bloksm 1990). The size nd number of gs cells re importnt s this determines whether they grow or not during proving process. The other importnt role of mixing is to give stbility to the gs cells occluded. Size of uniformity is importnt for gs cell stbility (vnvilet 1995). After mixing, dough is subjected to lrge extensionl strins in sheeting process, is nother development stge. In this stge, the gs cells subdivide incresing their concentrtion nd uniformity of size this enhnces the viscoelstic properties of the dough. Aertion during mixing chnges the dough properties physiclly nd chemiclly, ffecting the rheologicl properties of dough. Fermenttion follows mixing. The objective of fermenttion is to bring the dough to n optimum condition for bking. Fermenttion llows the dough to relx, yest to begin fermenting 1

20 nd producing crbon dioxide gs. Most of the crbon dioxide produced by the yest dissolves in the liquid dough phse. At concentrtion of 4.3 X 10-2 kmoles/m 3, the liquid phse of the dough becomes fully sturted with crbon dioxide nd subsequent production diffuses into gs cells t the sme rte tht is produced consequently the cells begin to expnd. The number of gs cells cn be incresed by punching nd molding during fermenttion process. In punching nd molding, the gs cell wlls subdivide to increse both their numbers nd concentrtion. Expnsion of the dough is cused by pressure bove tmospheric in the gs cells (Bloksm 1990). After fermenttion, the dough rests for minutes. Immeditely fter proofing nd moulding the cylinder is fitted into the bred pn. This newly rounded cylinder is proofed llowing the gs cells to expnd in size nerly 2x times before bking. During proofing, the dough undergoes chnges in height nd volume s well s texture nd density (Rosell 2011). Bking is the finl step in the bred-mking process. Fermenttion ends when dough is bked in n oven ( C, min). In the initil stges of bking, s the oven het penetrtes the dough, gses in the dough expnds. A finl increse in volume occurs nd the crust sets (Rosell 2011). As the temperture rises, the increse in dough volume is creted by yest producing crbon dioxide, evportion of wter vpor, nd resulting in more expnsion of existing gs cells (Cmpbell 2003). The gs cells continue to expnd until the structure sets or the stress on thin bubble cell wlls becomes to gret nd they rupture. The rupture of the cell wlls seprting the bubbles is clled colescence. During bking, strch geltiniztion occurs, protein dentures, the gluten strnds surrounding the individul gs cells become n porous network of cells, nd referred s bred crumb. Chemicl rections including Millrd or nonenzymtic browning rections re responsible for the brown color of the crust (Rosell 2011). 1.2 Fiber nd Its Helth Benefits Fiber intke hs incresed fter the food industry promoted the merits of including fiber in food products (Redgwell nd Fischer 2005). Fiber is known s roughge, nd is derived from plnt cell wlls. Fiber is composed of soluble dietry fiber nd insoluble dietry fiber. According to the AACC Dietry Fiber Definition Committee, Dietry fiber is the edible prts of plnts or nlogous crbohydrtes tht re resistnt to digestion nd dsorption in the humn smll intestine with complete or prtil fermenttion in the lrge intestine. Some of the primry sources of fibers include polyscchrides, oligoscchrides, lignin, cellulose nd its derivtives; 2

21 fruits, vegetbles, nd oil seed frctions (deftted mels nd hulls); nd certin frctions of cerel grins (corn brn, soy hulls, rye brn, spent grins, triticle brn nd whet brn). The reson for introducing fiber into the humn diet includes the helth benefits ssocited with fiber consumption. Severl epidemiologicl reserch observtions show tht dietry fiber consumption promotes beneficil physiologicl effects including mintennce of helth nd protection from diseses such s constiption, blood cholesterol ttenution, blood glucose ttenution, (Boyer nd Liu 2004; Scott et l 2008; Redgwell nd Fischer 2005). One importnt helth effect of dietry fiber is it is modifiction of the colonic microflor which consequently decreses the ph in the colon. This inhibits pthogenic bcteri, nd reduces the risk of colon cncer (Gibson et l 2004b). Other nutrition nd dietetic studies found tht low intke of dietry fiber is linked with helth problems such s diverticulr disese, coronry hert disese, obesity nd rectl cncer (Kendll et l 2010; Sivm et l 2010). Fiber enrichment of foods hs become hot topic of reserch Fiber-enriched Foods: Impct on the Industry The recommended dily dose of dietry fiber for helthy diet is between g per dy (Jones 2004). In previous yers, most of the popultion chose convenient foods tht were pltble nd lower in cost thn helthy foods such s whole grins, fresh vegetbles nd fruits (Adms 1997). The consumer surveys found tht public wreness of the benefits of consuming dietry fiber in their diets is incresing (Slon 2001; Krystllis et l 2008). The industry hd n obligtion to improve the nutritionl benefits of the products ever since the Helthfocus Interntionl Trends reported tht Europen nd Americn people climed the food lbel high fiber is n extremely importnt (Slon 2001). The Nutritionl Lbeling nd Eduction Act mde mndtory field for dietry fiber on nutrition lbels (Singh et l 2012). The food industry hs technologicl chllenges in incorporting dietry fiber into foods becuse fiber imprts functionl properties to the finished products. The functionl properties include incresed wter holding, gel forming, stbilizing nd thickening cpcities (Gelroth et l 2001; Dikemn et l 2006). The ddition of fiber lso ffects the rheologicl properties of the dough systems yielding higher wter bsorption nd lower extensibility (depending on the type of bked products being mde) (Gomez et l 2003; Sivm et l 2010). Dietry fiber ddition to products did not ppel the consumers. 3

22 1.2.2 Dietry Fiber in Bked Products Bked products re one of the most widely consumed foods, so dietry fiber in bked goods would be n esy wy of consumption to chieve the dily intke gols. Vrious reserch studies hs been conducted on dietry fiber sources in bred mking to develop bsic nd pplied informtion on the use of vilble, nturl nd reltively inexpensive fiber-rich mterils. There re severl fiber ingredients vilble to the bker nd reserchers hve reviewed their vilble forms, functionlity nd pplictions in the whet flour. Most fiber type breds contin two or more of these mterils nd the breds cn be plced into four generl clssifictions (Tble 1.1). Disserttion will focus on whet brn fiber. Tble 1.1 Clssifictions of fiber enriched breds (dpted from Dubois 1978) Fiber Source Mrketing Approch Reltive Fiber Content Multiple Grin All nturl Slightly more thn whole grin Multiple fiber source No cellulose High mounts of grin or legume fiber No cellulose Reltively high crude fiber All nturl Slightly higher thn bove clss Whole grin nd/or grin fiber nd/or legume fiber plus cellulose Cellulose s mjor fiber source Clorie reduction High crude fiber Fiber-rich ppernce Clorie reduction Highest crude fiber 1.3 Whet Brn Fiber content severl times tht of whole whet bred Highest of this type bred, severl times tht of whole whet bred Whet brn is by-product of milling whet. Roller milling produces clen seprtion of the brn nd germ from endosperm through consecutive steps including grinding, sieving, nd purifying steps (Hemdne et l 2016; Cmpbell 2007; Peyron et l 2002). Brn ctully hs severl lyers but is removed with ll the lyers intct. It is leurone cells, long with the more peripherl lyers plus the embryo, tht constitutes the brn frction. Whet brn contins 2% bioctive compounds including multiple vitmins, phenolic compounds, nd phytochemicls, within strong fibrous structure (Shewry 2009). These phytochemicls significnt in whole grin cerel (whet) nd include n-3 ftty cids, sulfur mino cids, oligoscchrides, lignin, minerls, trce elements, vitmins B nd E, crotenoids, polyphenols (especilly phenolic cids such s ferulic cid nd smller mounts of flvonoids nd lignns), lkylresorcinols, phytic cid, 4

23 betine, totl choline-contining compounds, nositols, phytosterols, policosnol nd meltonin. The helth benefits of the phytochemicls re listed in Tble 1.2 (Frdet et l 2010). The potentil helth benefits of high fiber food products hve been the subject of severl yers. Still, some processing is needed for pltbility nd nutrient biovilbility (Topping 2007).Evidence ccumulted from epidemiologicl nd experimentl reserch shows tht whet brn my reduce the risk of certin chronic diseses such s crdiovsculr disese, body weight mintennce, type 2 dibetes, blood pressure, circultory helth nd certin cncers (Montonen et l 2003; Koh-Bnergee et l 2004; Erkkil et l 2005; Behll et l 2006; Schtzkin et l 2007; Mellen et l 2009). Resercher suggest tht the consumption of fiber with combintion of components in the wholegrin mtrix my work together to imprt helth benefits (Frdet 2010). Whet brn is complex biologicl mteril chrcterized by specific histologicl structure nd diverse chemicl composition (Shetlr et l 1947). The brn mkes up bout 13% of the totl whet kernel. There re seven lyers in the brn s is shown in Figure 1.1. Mny lyers re incomplete or unrecognizble t mturtion so composition of the brn hs been debted. The epidermis nd hypodermis together constitute the outer pericrp, which is the outermost lyer. Brn is commonly divided into three regions: outer, immedite, or inner lyers (Jerovic et l 2010; Brron et l 2007). Adjcent to the outer pericrp is the inner pericrp which is composed of severl compressed cell lyers, the cross cells nd tube cells (Bohm et l 2002). The next lyer inwrds is the seed cot or test lyer, which is strongly pigmented, in red whet. Tightly bound to the internl surfce of the seed cot is the hyline lyer. The next lyer of brn is leurone lyer. It is considered ntomiclly prt of endosperm. The miller regrds the leurone s the innermost lyer of the brn. The mjority of minerl mtter locted in brn is found in the leurone lyer. The leurone contins one third of the whet grin s thimin content. The leurone grnules re proteineous nd rich in bsic mino cids (Bechtel et l. 2009). 5

24 Tble 1.2 Mjor helth benefits of bioctive compound found in whole-grin cerel (dpted from Frdet et l 2010) Helth Benefits Body-weight regultion nd obesity CVD nd hert helth Type 2 dibetes Cncers Gut helth Mentl/brin/nervous system helth nd neurodegenertive disorders Skeleton helth (i.e. bone, tendon, crtilge, collgen, rticultion nd teeth) Antioxidnt protection (development of diseses in reltion to incresed oxidtive stress) Bioctive compound Insoluble fiber, fructns, resistnt strch, Zn, C, tocotrienols, phenolic cids, flvonoids, choline, p-minobenzoic cid α-linolenic cid, methionine, oligoscchrides, soluble fiber, resistnt strch, phytic cid, Mg, Mn, Cu, Se, K, thimin, riboflvin, nicotinic cid, pyridoxine, foltes, tocopherols, tocotrienols, phylloquinone, b-crotene, lutein, zexnthin, phenolic cids, flvonoids, lignns, phytosterols, betine, choline, inositols, policosnol, p- minobenzoic cid, g-oryznol, vennthrmides, sponins Soluble fiber, resistnt strch, phytic cid, Mg, Zn, Se, K, C, tocopherols, tocotrienols, phenolic cids, flvonoids, betine, inositols, phytosterols, g-oryznol, sponins α-linolenic cid, oligoscchrides, soluble fiber, insoluble fiber, resistnt strch, lignin, phytic cid, Zn, Mn, Cu, Se, P, C, riboflvin, nicotinic cid, pyridoxine, foltes, tocopherols, tocotrienols, β-crotene, β-cryptoxnthin, phenolic cids, flvonoids, lignns, lkylresorcinols, betine, choline, inositols, phytosterols, meltonin, p-minobenzoic cid, sponins α-linolenic cid, oligoscchrides, soluble fiber, insoluble fiber, resistnt strch, riboflvin, pntothenic cid, phenolic cids, policosnol, g-oryznol α-linolenic cid, methionine, oligoscchrides, Fe, Mg, Zn, Cu, P, C, N, K, thimin, riboflvin, nicotinic cid, pntothenic cid, pyridoxine, biotin, foltes, tocotrienols, phenolic cids, choline, inositols, policosnol, meltonin, g-oryznol, sponins α-linolenic cid, Fe, Mg, Zn, Mn, Cu, P, C, K, nicotinic cid, tocotrienols, phylloquinone, β-cryptoxnthin, flvonoids, lignns, p-minobenzoic cid Reduced glutthione, methionine, cystine, lignins, phytic cid, Mg, Fe, Zn, Mn, Cu, Se, thimin, riboflvin, tocopherols, tocotrienols, β-crotene, lutein, zexnthin, β- cryptoxnthin, phenolic cids, flvonoids, lignns, lkylresorcinols, betine, choline, policosnol, meltonin, g-oryznol, vennthrmides, sponins 6

25 The complete seprtion of brn from endosperm in flour milling is due to differences in the mechnicl properties of brn nd endosperm (Peyron et l 2002). The bility to seprte components of the kernel my rely solely on brn lyer chemicl differences (Evrs nd Millers 2002). In whet brn, leurone cells re high in proteins, ferulic cid, nd lipids, nd re composed of thick nonlignified cell wlls, nd the pericrp hs thick lignified cells (Fulcher nd Duke 2002; Cheng et l 1987). Brn hs lrge concentrtions of brnched heteroxylns, cellulose nd lignins (Hemery et l 2011). Figure 1.1 The seven lyers constituting of whet brn (dpted from Frdet 2010) Whet Brn in Bred-mking Whet brn is used in the feed industry s livestock feed. Due to expnding mrket for helth foods, whet brn is considered s nutritionlly vluble ingredient nd widely used s source of fiber for incorporting into processed foods, minly bred. However, incorporting whet brn in bred generlly decreses its structure nd sensory qulity. This cn cuse reduced consumer cceptnce. As result, brn brings chllenges in to the production of fiber-rich 7

26 products: mintining functionlity nd qulity equivlent to trditionl products vilble in the mrket. Besides ffecting finl product qulity chrcteristics, incorporting whet brn into flour systems lso results in chnges in dough properties nd processing behviors (Chssgne- Berces et l 2011). Studies hve reported tht whet germ, red-dog nd brn frctions of diverse whet vrieties hve different effects on bred qulity (Li et l 1989; Sidhu et l 1999; Noort et l 2010; Hemdne et l 2015). 1.4 Technologicl Chllenges-Brn in Bked Goods The first chllenge to brn incorportion begins with the current diversity of mill-derived brn products. Depending on the mill, whet brn contributes to by-products including corse brn, fine brn, middling or shorts nd red-dog. The different vrieties of brn frctions my hve their own specific properties which ffect the whet brn behvior in bred mking. Hemdne et l (2015) reported tht fine brn nd red-dog frctions hve impct tht is more negtive effects on bred mking thn do corse brn frctions Interction with Wter Brn intercts with wter nd hs the bility to bsorb considerble mounts of wter. Brn retins wter by vriety of mcro-, micro- nd nnoscle, nd moleculr level mechnisms. At the mcro level retention is ttributed to filling of void spces between prticles; while on micro level, the void spce in pericrp cells nd spce in between the tissue lyers is filled. Cpillry mechnisms re involved in the wter binding on the nnoscle. Chplin(2003) stted tht brn is rich in polyscchrides which cn bind wter on moleculr level by formtion of hydrogen bonds. This mechnism contributes to wter uptke phenomen nd considered s function of whet brn prticle size (Hemdne et l 2016). Jcobs et l (2015) reported tht lrge prticle size brn ws ble to retin more wter during unconstrined hydrtion, due to its higher potentil to bind wter in its intct micropores. In bred mking, brn is hydrted during mixing nd exposed to kneding nd the hygroscopic forces pplied by vrious flour components. Wter bound through these mechnisms is reltively wekly bound nd releses in the presence of these externl force becuse stcking nd micropores do not contribute to hydrtion (Zhng nd Moore 1999). The tendency of brn to bsorb wter might result in competition between brn nd flour constituents 8

27 for wter. This view is consistent nd hs been found to be correlted to the effect of whet brn on bred mking. (Roozendl et l 2012; Schmiele et l 2012; Hemdne et l 2016). However, it is difficult to estimte the exct significnce of brn hydrtion behvior in bred mking functionlity becuse no cler scientific evidence is vilble to support the hypotheses. The brn ddition hs detrimentl effects on bred qulity in terms of functionl nd s well s sensory properties of brn. Addition of whet brn to whet flour generlly increses required wter bsorption. The dditionl wter is retined by the lof during bking, giving hevier lof nd decresed bred volume. The studies reported tht this dditionl wter is lso vilble for strch geltiniztion during bking, which lowers the strch geltiniztion temperture nd reduces gs retention during bking nd thereby lowers the lof volume. This mechnism implies tht the effect of brn on gs retention is minly during bking. The dverse effects of the whet brn incresed with incresing levels of brn in the bred (Zhng nd Moore 1999; de Kock et l 1999; Cmpbell et l 2008; Seyer nd Gelins 2009). Schmiele et l (2012) reported decrese of specific volumes when whet flour ws substituted with whet brn t higher concentrtions (20%, 30% nd 40%) nd decresed lof volume. Other studies reported tht effect of brn ddition on crumb texture ws not due only to reduced lof volume. Mjzoobi et l (2013) observed tht in flt breds where lof volume is not importnt, the qulity of crumb texture decresed nd drker crumb color ws observed by incorporting brn. de Kock et l (1999) found tht the deleterious impct of brn in bred cn hve both physicl nd chemicl cuses Physicl Hindrnce nd Disruption Effect The detrimentl effect of brn ddition on bred mking cn be ttributed to the dilution of gluten proteins. Brn might interrupt gluten development by preventing proper contct between flour prticles. There might be dditionl negtive effects not mply covered by gluten dilution. Frinogrph studies found longer dough development times when higher levels of brn were replced with flour (Snz Penell et l 2008). It my lso be tht the incorportion of brn prticles into the gs cell wlls limits their bility to expnd resulting in the collpse, leding to colescence, nd leding to low gs retention in the dough, low bred volume nd dense crumb texture of the finl product (Gn et l 1992). 9

28 Severl workers hve considered the mechnicl effect of brn is it physiclly disrupts gluten films during the dough formtion in the mixer. Gluten is stretched into thin films during the lter stges of proving nd erly stges of bking. (Zhng nd Moore 1997; Cmpbell et l 2008). The uthors suggested tht in no-time bredmking processes, brn could ffect the initil ir content nd bubble size distribution nd finlly the bked lof volume nd crumb structure. The brn prticles might force gs cells to expnd in prticulr wys on pierce the gs cells leding to colescence (Cuvin et l 1999; Cmpbell 2003). The rheologicl properties of brn supplemented doughs my be ttributed to wek nd gluten network due to disruption by brn prticles. There cn be cler cut beneficil effects on dough properties of brn ddition. Ozboy nd Koksel (1997) reported tht soft white winter whet corse brn dded flour incresed the dough resistnce to overmixing nd to extension s mesured by Frinogrph nd Extensigrph respectively. Lter, when the corse brn ws dded to strong flour from hrd red winter whet, similr trend ws observed. 1.5 Previous Studies Extensive reserch hs been done in brn ddition to dough systems nd hs focused minly on bred. As discussed erlier, bred is highly erted nd brn physiclly disrupts the gluten films during mixing. Incorporting brn into the bred products is not n idel vehicle for delivering brn into diet. Severl uthors hve worked on including brn into less or non-erted products such s ckes, cookies, biscuits, pizz (Mjzoobi et l 2014; Gujrl et l 2003; Protonotriou et l 2016; Pcheco de Delhye et l 2005) Physicl nd Structurl Properties of Dough Systems The deleterious effect of brn cn depend on type nd level of brn dded to the dough. Incresed level of brn ddition generlly increses the wter bsorption of the doughs incresed lof weight; incresed dough stickiness, decresed mixing tolernces, dough strength nd extensibility. Brn dditions reduced the lof volume nd specific volume, produced corser structure, nd reduced crumb structure with drk crumb color (Gn et l 1992; Zhng nd Moore, 1997, 1999; de Kock et l., 1999; Cmpbell et l 2008; G omez et l 2011; Schmiele et l 2012). 10

29 Other sources of fiber such s ot brn, inulin, dte fiber, pe nd brod ben pod fiber hve been studied in reltion to whet flour dough formultion. The ddition of these fibers lso modified bred mking performnce of whet doughs, ffected mixing properties (Cmpbell et l 2008), nd rheologicl behvior (Peressini et l 2009; Bonnnd-Ducsse et l 2010) nd viscometric ptterns (Fendri et l 2016). Addition of fiber t lower levels strengthened the structure of the dough nd improved its qulity (Sivm et l 2011); however, excessive mounts of fiber hd negtive effect on gluten network formtion nd reduced the qulity of bred (Noort et l 2010; Ahmed et l 2015). The structurl properties of the bred crumb cn be ssessed by C-Cell Imge nlysis. Vrious other techniques such s imge nlysis nd X-ry microtomogrphy (XMT) hve been used to evlute the microstructurl properties of bred crumb to determine the reltionship between ir incorportion, expnsion nd cell structure. Studies hve been done on whet flour doughs using XMT nlysis to evlute t the chnges in gs cell expnsion during proofing (Bbin et l 2006). The nlysis determined tht ir cell growth ws unrestricted nd verge cell wll thickness ws similr to dough during the initil stges of the proofing. The ir cells begin to grow closer nd more susceptible to integrte s proofing continued nd lrger cells were creted cusing colescence. Perez-Nieto et l (2010) studied dough structure chnges nd their reltionship to dough temperture, mss loss nd lof height during bking by using imge nlysis techniques. The results showed dough expnsion nd colescence of the bubbles during initil stges of bking. The gretest dough disruption ws significnt on crumb dough structure during the initil stge of bking. Besbes et l (2013) evluted the cellulr structure of bred under different bking conditions using XMT nlysis. The studies showed tht the structurl properties of the crust nd the crumb in terms of ir cell size were influenced by heting rte. Vn Dyck et l (2014) studied the physicl property effects of brn ddition to pn bked white bred. The results reveled tht brn cused reductions in lof volume, n incresed cell wll thickness nd n incresed number of closed pores. Structure thickness nd number of closed pores were found to be higher in crust res nd lower in crumb res in brn ddition to pn bred. 11

30 1.5.2 Rheologicl Properties Dynmic rheologicl testing hs been the preferred pproch for exmining structurl nd fundmentl properties of whet flour doughs nd proteins (Song nd Zheng 2007). This rheologicl testing hs become populr becuse of its chrcteristic nd sensitive response to the structurl vritions (Tronsmo et l 2003). Dough rheologicl properties hve been investigted using empiricl nd dynmic rheologicl mesurements (Mni et l 1992; Rouille et l 2005; Dobrszczyk 2004). Studies on whet doughs show tht not ll rheologicl mesurements cn predict the bking qulity of different flours (Amemiy nd Menjivr 1992; Sfri-Ardi nd Phn-Thien 1998), s mesurements cn differ in terms of mgnitude nd the type of pplied deformtion. Amirkveei et l (2009) studied the effect of treted nd untreted brn on liner nd non-liner behvior using dynmic oscilltory tests. The studies showed tht untreted brn wekens the gluten mtrix nd on the other hnd the treted brn strengthens the protein mtrix to some extent. Severl other reserchers hve studied the influence of other dietry fibers such s inulin, β-d-glucn on dough systems (Peressini nd Alessndr 2009; Ahmed 2014). Reserch done by Bonnnd-Ducsse et l (2010) studied the effect of whet dietry fibers on bred dough development nd its rheologicl properties. Severl wter-unextrctble nd wter extrctble rbinoxylns frctions of whet fiber were isolted from strchy endosperm, leurone lyer nd brn when dded up to 10%, to stndrd flour nd studied through mixing tests, nd rheologicl tests t smll nd lrge deformtions. Wter-unextrctble rbinoxyln in the dough led to decrese in pek time nd to slight increse in pek bndwidth. Shorter development times suggested tht dough ws homogenized more rpidly by the presence of wter-unextrctble rbinoxylns wheres s the increse of bndwidth suggests tht dough displyed more instntneous resistnce to elongtion. Similr studies by Gomez et l (2003) nd Peressini et l (2009) observed tht wter bsorption by dough incresed nd dough tencity incresed with incresing insoluble whet fiber content. The smll deformtion tests results showed on increse in viscoelstic moduli with fiber ddition. The increse of viscoelstic moduli my be ttributed to the reduction of polymer lubriction by wter due to the competition of wter bsorption between gluten nd fiber (Izydorczyk et l 2001; Wng et l 2003), or to the fibers cting s filler in viscoelstic mtrix (Uthykumrn et l 2002). Viscoelstic properties of doughs t different wter bsorption levels were lso evluted with this method s 12

31 the Frinogrph wter bsorptions do not llow the decoupling of the effects of hydrtion nd fiber (Peressini et l 2009). The storge modulus of inulin dough smples ws lower thn tht of the control doughs nd trend of decresing G with increse of dietry fiber content ws identified. Similr reserch conducted by Rouillé et l (2005) reported n pprecible decrese in the liner study-stte creep complince of doughs t fixed wter ddition s low moleculr weight sugr content of soluble frctions incresed. Lrge deformtion tests such s creep nd creep recovery were performed on the wterunextrctble nd wter extrctble supplemented doughs (Bonnnd-Ducsse et l 2010). This test llows chrcteriztion of the viscoelstic behvior of the dough t long times nd the determintion of the stedy flow viscosity of highly viscoelstic mterils. For creep stress vlues σ < 200 p, creep curves were close to ech nd showed liner limit region. Above the creep stress vlue, the doughs exhibited time-dependent flow behvior with yield stress. Lrge deformtion mesurements re more suitble for testing dough qulity s food product s it cn be relted to bred eting qulity. The lrge deformtion tests re conducted where the stress exceeds the yield vlue. The most commonly dpted method for lrge deformtion testing of dough is extension. Vrious instruments re vilble for performing extension tests on dough such s the extensogrph, lveogrph, Kieffer rig dough extensibility test nd Instron. In the pst, much reserch hs been done on dough nd gluten extensibility using ttchments on the Universl Testing Mchine on the Texture Anlyzer (Kieffer et l 1998; Suchy et l 2000; Tronsmo et l 2003; Sliwinski et l 2004, b). Tronsmo et l (2003) showed the difference in the bredmking performnce of six different whet flours nd determined thn mximum resistnce to extension nd totl extensibility using Kieffer dough nd gluten extensibility rig on the TA.TX2i texture nlyzer. They performed extensibility tests on whet flour doughs nd gluten with nd without slt. Results showed tht the extensibility of unslted doughs ws more influenced by flour protein content thn the extensibility of slted doughs. Mesurement on gluten gve purer indiction of protein properties. Fresh gluten from flours of high protein content ws less elstic thn ws gluten from flours of similr mixing strength but lower protein content. Another recent study done by Ahmed et l (2015) using smll mplitude oscilltory rheology nd creep behvior found the mechnicl rigidity of the β-glucn concentrte 13

32 contining doughs strongly influenced by prticle size, prticle-to-wter rtio nd temperture. The studies suggested tht lrge prticles occupy more spce during ggregtion thn do smll prticles due to less efficient prticle pcking. This leds to more volume occuption by lrge prticles nd n increse in flow resistnce (Quemd 1998). In ddition, the smllest prticles would be expected to hve lower mechnicl strength becuse cellulr structure brekdown of the prticles increses due to milling. The heting tempertures hd lest effected on oscilltory mesurements. The solid-like property of the dough grdully decresed with incresing dough wter content. The finest prticle dough showed the mximum strin during creep test confirming its viscoelstic nture. Most reserchers hve studied the rheologicl properties such s storge modulus (G ), loss modulus (G"), nd loss tngent (tn δ) of whet flour doughs nd good nd poor protein qulity flours (Miller nd Hoseney 1999; Khtkr et l 1995 nd Toufeli et l 1999; Peressini et l. 2009; Bonnnd-Ducsse et l. 2010). In whet doughs, oscilltory mesurements in the liner viscoelstic region hve not been ble to predict the bking qulity of different flours. The results of lrge deformtion mesurements correlte well with the properties of the overll network structure (Stdig 1993). Whet brn ddition hs dverse effects on dough qulity, depending on brn s composition nd prticle size. Severl reserchers hve studied the brn ddition effect on bred qulity nd found tht bred volume is highly correlted with the gluten yield. The constituents of the whet brn interct with the gluten physiclly or chemiclly, negtively influencing gluten ggregtion (Wng et l 2003; Noort et l 2010) The previous reserch findings on the rheologicl properties of dough nd gluten used rheometric techniques. Very little informtion is vilble on the effects of brn prticle size ddition using fundmentl dough rheology nd structurl properties. Further investigtion of the brn prticle size effect on whet flour dough mixing behvior, nd smll nd lrge deformtion mesurements is needed. 1.6 Hypothesis Previous studies explined the effects of brn on bred qulity with widely different hypothesis. In series of studies, Li et l (1989, 1989, b) proposed tht presence of brn prticles chnges the ppernce nd the hndling properties of the dough. They lso ttribute the effects to the ctions of enzymes nd reducing components in the short frctions. Gn et l (1992) hypothesized tht the ddition of fiber dilutes gluten network formtion. In ddition, the 14

33 physicl disruption of the gs cells or by biochemicl mechnism by lipse ction cuses the effects on lof volume. Courtin nd Delcour (2002) hypothesized tht effects of wter unextrctble rbinoxylns present in minor whet flour components such s lipids, endogenous enzymes, sh nd non-strch polyscchrides destbilizes the dough structure by piercing the gs cells nd forming physicl brriers for the gluten network development. In nother series of reserch ppers, Wng et l (2003, b, 2004, b) explined the effects of wter rbinoxylns nd wter insoluble solids from whet flour hs being due to effects on gluten formtion. They further hypothesized tht presence of brn prticles in dough cn ct through combintion of both physicl nd chemicl mechnisms. The physicl mechnism ws correlted to wter binding nd prticle size; wheres the chemicl mechnism ws linked to the presence of ferulic cid. 1.7 Scope nd Approch Introduction of cerel grin brn into humn diet hs proven to hve significnt helth benefits (reducing the coronry hert disese, some colon diseses, nd type 2 dibetes risks). A fiber-rich mteril like whet brn is dded to the whet flour in the production of high-fiber breds to improve the nutrition vilbility. The production of whole whet breds hs grown to become mjor portion of the bred industry in few decdes. The ddition of brn fiber cuses mjor chnges in processing behvior nd qulity chrcteristics of bred such s lof volume, texture nd flvor. Reserch hs discovered tht ddition of brn fiber into flour cuses wekening of cell structure nd reduces gs retention, s the fibrous mterils tend to cut the gluten strnds. Studies exmined the rheology of whet brn flour dough components such s strch nd protein, since they hve the bility to form continuous mcromoleculr network which gives rise to viscoelstic behvior. There hs been no combined effort to revel the effect of brn on dough physicl properties tht re ttributed to disruption of the gluten protein mtrix. Bsed on the bove, the overll hypotheses of this study is tht the nture nd extent of brn interctions with the gluten mtrix ply dominnt role in both in-process dough nd finl product qulity. Therefore, the purposeful mnipultion of the brn interctions which gluten protein network, should minimize the dverse processing or product chrcteristics resulting from brn inclusion. Bsed on the hypothesis, this disserttion seeks to provide tht detiled 15

34 fundmentl understnding of biochemicl, rheologicl nd micro-structurl roles of brn in whet dough systems using trditionl cerel chemistry pproches combined with fundmentl rheology nd x-ry microtomogrphy. The specific objectives of this disserttion study were: Chpter-2. Study of effect of hrd nd soft whet brn sources, vrying brn size nd brn inclusion levels on dough development, crumb structure nd texture of the end product. Dough development ws evluted by empiricl methods using Frinogrph, Mixogrph nd Mixolb. The bking performnce ws ssessed through C-Cell imging (mcro imging) nd by x-ry microtomogrphy (XMT) (micro imging). The bred texture ws studied using the TAXT2 Texture Anlyser. Chpter-3. Study of the effects of brn frctions of vrying ntomicl origin nd size t vrying replcement levels on dough development, used smll nd lrge deformtion rheologicl techniques. The brn frctions were chrcterized into two ctegories, different prticle size with equivlent composition nd equivlent prticle size with different composition. The empiricl rheologicl methods such s Frinogrph nd Mixogrph ws used to study dough development. The viscoelstic properties of brn doughs were evluted by smll nd lrge deformtion tests. Smll deformtion tests including, frequency sweeps nd temperture sweeps were performed to understnd the nture of brn nd strch-gluten interctions in the doughs. Lrge deformtion tests including creep recovery test nd Kieffer rig dough extensibility tests were performed to understnd the dough qulity nd its effect on the end product. 16

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40 Montonen, J., Knekt, P., Jrvinen, R., Arom, A., Reunnen, A. (2003). Whole grin nd fiber intke nd the incidence of type-2 dibetes. Americn Journl of Clinicl Nutrition, 77(3): Noort, M. W. J., Hster, D. V., Hemery, Y., Schols, H. A., Hmer, R. J. (2010). The effect of prticle size of whet brn frctions on bred qulity Evidence for fiber-protein interctions. Journl of Cerel Science, 52: Ozboy, O., Koksel, H. (1997). Unexpected strengthening effects of corse whet brn on dough rheologicl properties nd bking qulity. Journl of Cerel Science, 25: Pcheco de Delhye, E., Jimenez, P., Perez, E. (2005). Effect of enrichment with high content dietry fiber stbilized rice brn flour on chemicl nd functionl properties of storge frozen pizzs. Journl of Food Engineering, 68:1-7. Peressini, D., Sensidoni, A. (2009). Effect of soluble dietry fiber ddition on rheologicl nd bredmking properties of whet doughs. Journl of Cerel Science, 49: Perez-Nieto, A., Chnon-Perez, J. J., Frrer-Rebollo, R. R., Gutierrez-Lopez, G. F., Almill- Beltrn, L., Clderon-Dominguez, G. (2010). Imge nlysis of structurl chnges in dough during bking. LWT- Food Science nd Technology, 43: Peyron, S., Churnd, M., Rouu, X., Abecssis, J. (2002). Reltionship between brn mechnicl properties nd milling behvior of durum whet influence of tissue thickness nd cell wll structure. Journl of Cerel Science, 36: Protonotriou, S., Btzki, C., Ynniotis, S., Mndl, I. (2016). Effect of jet milled whole whet flour in biscuit properties. LWT-Food Science nd Technology, 74: Quemd, D. (1998). Rheologicl modeling of complex fluids. I. The concept of effective volume frction revisited. Europen Physics Journl of Applied Physics, 1: Redgwell, R. J., Fischer, M. (2005). Dietry fiber s verstile food component: An industril perspective. Moleculr Nutrition nd Food Reserch, 49: Roozendl, H., Abu-Hrdn, M., Frzier, R. A. (2012). Thermogrvimetric nlysis of wter relese from whet flour nd whet brn suspensions. Journl of Food Engineering, 111: Rosell, C. M. (2011). The science of doughs nd bred qulity. In Flour nd breds nd their Fortifiction in Helth nd Disese Prevention. pp Elsevier, Inc. Rouille, J., Dell Vlle, G., Lefebvre, J., Sliwinski, E., vnvliet, T. (2005). Sher nd extensionl properties of bred doughs ffected by their minor compounds. Journl of Cerel Science, 42:

41 Sfri-Ardi, M., Phn-Thien, N. (1998). Stress relxtion nd oscilltory Tests to distinguish between doughs prepred from whet flours of different vrietl origin. Cerel Chemistry, 75: Snz Penell, J. M., Collr, C., Hros, M. (2008). Effect of whet brn nd enzyme ddition on dough functionl performnce nd phytic cid levels in bred. Journl of Cerel Science, 48: Schtzkin, A., Mouw, T., Prk, Y., Subr, A. F., Kipnis, V., Hollenbeck, A., Leitzmnn, M. F., Thompson, F. E. (2007). Dietry fiber nd wholegrin consumption in reltion to colorectl cncer NIH AARP diet nd helth study. Americn Journl of Clinicl Nutrition, 85: Schmiele, M., Jekel, L. Z., Ptricio, S. M. C., Steel, C. J., Chng, Y. K. (2012). Rheologicl properties of whet flour nd qulity chrcteristics of pn bred s modified by prtil dditions of whet brn or whole grin whet flour. Interntionl Journl of Food Science nd Technology, 47: Scott, K. P., Duncn, S. H., Flint, H. J. (2008). Dietry fiber nd the gut microbiot. Nutrition Bulletin, 33: Seyer, M.E., Gelins, P. (2009). Brn chrcteristics nd whet performnce in whole whet bred. Interntionl Journl of Food Science nd Technology, 44: Shetlr, M. R., Rnkin, G. T., Lymn, J. F., Frnce, W. G. (1947). Investigtion of the proximte chemicl composition of the seprte brn lyers of whet. Cerel Chemistry, 24: Shewry, P. (2009). Whet. Journl of experimentl Botny, 60: Sidhu, J. S., Al-Hooti, S. N., Al-Sqer, J. M. (1999). Effecting of dding whet brn nd germ frctions on the chemicl composition of high-fiber tost bred. Food Chemistry, 67(4): Singh, M., Liu, S. X., Vughn, S. F. (2012). Effect of corn brn prticle size nd substitution on psting chrcteristics of whet flour. AACC Annul meeting Abstrct. Sivm, A. S., Sun-Wterhouse, D., Quek, S. Y. nd Perer, C. O. (2010). Properties of bred dough with dded fiber polyscchrides nd phenolic ntioxidnts-a review. Journl of Food Science, 75(8): Sliwinski, E. L., Kolster, P. A., Prins, A., vn-vilet, T. (2004). On the reltionship between gluten protein composition of whet flours nd lrge-deformtion properties of their doughs. Journl of Cerel Science, 39: Slon, A. E. (2001). Growing demnd for dietry fiber. Functionl Food Nutrceuticls, Sept./Oct.,

42 Song, Y., Zheng, Q. (2007). Dynmic rheologicl properties of whet flour dough nd proteins. Trends Food Science nd Technology, 18: Stdig, M. (1993). Rheologicl behvior of biopolymer gels in reltion to structure. PhD thesis. Chlmers Univ. of Technology: Gothenburg, Sweden. Suchy, J., Lukow, O. M., Ingelin, M. E. (2000). Dough micro-extensibility method using 2-g mixogrph nd texture nlyzer. Cerel Chemistry, 77(1): Sudh, M. L., Vetrimni, R., Leelvthi, K. (2007). Influence of fiber from different cerels on the rheologicl chrcteristics of whet flour dough nd on biscuit qulity. Food Chemistry, 100(4): Topping, D. (2007). Cerel complex crbohydrtes nd their contribution to humn helth. Journl of Cerel Science, 46: Toufeili, I., Ismil, B., Shdrevin, S., Blbki, R., Khtkr, B. S., Bell A. E., Schofield, J. D. (1999). The role of gluten proteins in the bking of Arbic bred. Journl of Cerel Science, 30: Tronsmo, K., Mgnus, E., Fergested, E., Schofield, J. (2003). Reltionships between gluten rheologicl properties nd herth lof chrcteristics. Cerel Chemistry, 80: Tronsmo, K., Mgnus, E., Brdseth, P., Schofield, J., Amodt, A., Fergestd, E. (2003b). Comprison of smll nd lrge deformtion rheologicl properties of whet dough nd gluten. Cerel Chemistry, 80: Uthykumrn, S., Newberry, M., Phn-Thien, N. nd Tnner, R. (2002). Smll nd lrge strin rheology of whet gluten. Rheologicl Act, 41: vn Dyck, T., Verboven, P., Herremns, E., Defreye, T., Vn Cmpenhout, L., Wevers, M., Cles, J., Nicoli, B. (2014). Chrcteriztion of structurl ptterns in bred s evluted by X-ry computer tomogrphy. Journl of Food Engineering, 123: vnvliet, T Physicl fctors determining gs cell stbility in dough during bred mking. In: Schofield, J. D. (Ed.), Whet Structure, Biochemistry nd Functionlity, The Royl Society of Chemistry, Cmbridge, UK. pp Wng, M. W., Hmer, R. J., vnvliet, T., Gruppen, H., Mrseille H., Weegels, P. L. (2003). Effect of wter unextrctble solids on gluten formtion nd properties: mechnistic considertions. Journl of Cerel Science, 37: Wng, M. W., Oudgenoeg, G., vnvliet, T., Hmer, R. J. (2003b). Interction of wter unextrctble solids with gluten protein: Effect on dough properties nd gluten qulity. Journl of Cerel Science, 38: Wng, M. W., vnvliet, T., Hmer, R. J. (2004). Evidence tht pentosns nd xylnse ffect there-gglomertion of the gluten network. Journl of Cerel Science, 39:

43 Wng, M.W., vnvliet, T., Hmer, R. J. (2004b).How gluten properties re ffected by pentosns. Journl of Cerel Science, 39: Weipert, D. (1990). The benefits of bsic rheometry in studying dough rheology. Cerel Chemistry, 67: Zhng, D., Moore, W. R. (1997). Effect of whet brn prticle size on dough rheologicl properties. Journl of Science Food nd Agriculture, 74: Zhng, D., Moore, W.R. (1999). Whet brn prticle size effects on bred bking performnce nd qulity. Journl of Science Food nd Agriculture, 79: Zheng, H., Morgenstem, M. P., Cmpnell, O. H., Lrsen, N. G. (2000). Rheologicl properties of dough during mechnicl dough development. Journl of Cerel Science, 32:

44 Chpter 2 - Effects of hrd nd soft whet brns t vrying size nd inclusion levels on dough development nd crumb structure nd texture of the end products Abstrct The effects of brn source, brn size (s is, corse nd fine) nd ddition level (0-10%) on wter bsorption nd rheologicl properties of hrd nd soft whet dough systems of different strength, nd the lof volume, crumb texture, nd microstructure of the resulting bked products were studied. Hrd red winter (HRW) nd soft winter (SW) flours nd their respective brn frctions were used. The dough rheologicl properties were studied using the Frinogrph, Mixogrph nd MixoLb. HRW nd SW brn dditions resulted in higher wter bsorptions irrespective of the flour type nd brn source. Fine brn dditions cused slightly higher wter bsorption vlues followed by corse nd s is brn sizes. Both HRW nd SW brn dditions decresed the dough stbility of HRW flour, while it improved the stbility of SW flour. The pek time nd pek vlue were higher in HRW flour doughs compred to SW flour, s expected. Mcro nd microstructure of bked products were significntly ffected by brn ddition levels s well s by brn type. Five nd 10 % HRW brn ddition in HRW bred formultions resulted in 8-23% decrese in lof volume while SW brn dded t the sme level cused only 3-11% decrese in lof volume. X-ry microtomogrphy dt indicted tht brn ddition resulted in significnt decrese in totl number of ir cells nd slight increse in their verge sizes irrespective of brn type nd ddition level. Incresed brn ddition irrespective of brn source nd size cused grdul shift in the cell wll thickness nd ir cell size distributions towrds higher vlues. SW flour resulted in hrder crumb texture thn tht of HRW flour breds s expected from lower their lof volume. Brn ddition further incresed the hrdness vlues irrespective of brn type nd size. Cohesiveness scores of HRW flour breds decresed drmticlly with the ddition of HRW brn while SW brn showed n insignificnt effect. Overll, SW brn dditions hd less detrimentl effects on mixing nd bking performnce of HRW flour. Added brn slightly improved mixing, bking nd end qulity prmeters of SW flour systems. 26

45 2.1 Introduction There is n incresed demnd nd interest in food systems contining whole grins due to the helth benefits ttributed to the vrious phytochemicls nd nutrients ssocited with the non-endosperm portions (brn nd germ) of cerels. Studies reported nd documented the positive effects of whole grin consumption on type 2 dibetes risk (Montonen et l 2003), body weight mintennce (Koh-Bnergee et l 2004), blood pressure nd circultory helth (Behll et l 2006; Erkkil et l 2005). Whole grin products re rich source of fiber. The nutritionl benefits of fiber hve led to increses in the production of high-fiber products. Whet brn, in prticulr, is one of most essentil dietry fiber sources used in the bred mking industry (Vetter 1998). Severl studies hve been done on nutritionl benefits of dietry fiber sources nd especilly dietry fiber in whet brn nd it hs been proven tht it reduces the risk of colon cncer (Zhng nd Moore, 1999). Severl other studies hve relted consumption of dietry fiber nd whole grins with reduction in serum cholesterol, nd lower risk for coronry rtery disese nd certin forms of cncer (Burkitt 1971; Kntor et l 2001; Decker et l 2002). The cerel foods industry hs responded to the consuming public's interest in whole grin foods by developing nd introducing new or reformulted products. In 2005, this ccounted for more thn 650 introductions (Neilsen 2005). A significnt number of mjor US food compnies hve lunched such new or reformulted products, which in turn, hve ffected the sles of cerel products positively. The inclusion of the non-endosperm components to dough systems, however, presents technologicl chllenges. Incorportion of whet brn into bred-mking flour results in mny mjor chnges in dough properties, processing techniques nd bred qulity chrcteristics (Prentice nd D Appoloni 1977; Li nd Hoseney 1989; Li et l 1989). Reserch by Pomernz et l (1977) hs shown tht the ddition of whet brn to bred formultion incresed wter bsorption, decresed lof volume, impired crumb texture, drkened crumb color nd reduced crumb softness. The dverse effects of the whet brn incresed with higher levels of brn substitution in the formul. The effects of prticle size reduction on the physicl nd functionl properties of whet brn hve been studied extensively (Shetlr nd Lymn 1944; Moder et l 1984; Gllird nd Gllgher 1988; Zhng nd Moore 1997). However, brn prticle size is still controversil 27

46 issue s it regrds the bred-mking performnce. Shetlr nd Lymn (1944) reported tht the lof volume of whet brn bred is negtively correlted to brn prticle size when the brn prticle size ws obtined by sifting process. The different prticles sizes produced by sifting my differ in composition becuse brn consists of mny lyers including the underlying leurone cells. Moreover, different brn prticle size distributions cn be produced by sifting nd grinding processes. The method of brn preprtion ppers to be of criticl importnce nd could be the reson for differences in the published informtion. Zhng nd Moore (1997) reported tht brn prticle size produced by grinding process ffected dough rheologicl properties. Corse whet brn prticle size hd better bking qulity s compred to fine brn prticle size. Moder et l (1984) reported tht fine whet brn hd better bking performnce compred to corse brn, while Gllird nd Gllgher (1988) indicted tht fine whet brn prticle size reduced the bred qulity. The effects of brn on dough physicl properties, which re ttributed to disruption of the gluten protein mtrix, re not well understood on fundmentl level. The nture nd extent of brn interctions with the gluten protein mtrix ply dominnt role in both in-process dough nd finl product qulity of whole grin bked goods. With the growing pprecition by the generl public tht bked goods contining whole grins provide helth benefits, there is need to understnd the specific effect of whole grin components on dough rheology. Processing nd hndling of doughs with high sh content due to brn is known to be more difficult (Fridi 1990), nd more complete understnding of the effect of whole grin components such s brn on dough rheology will llow cerel scientists to understnd the source of the difficulties so tht they cn be controlled. Antoine et l (2004) reported the reltive distribution of outer grin lyers in reltion to the prticle sizes of brn frctions. The differences in performnce of brn-dded flour systems needs to be further explored with regrd to their specific chemicl composition, wter bsorption, nd other physicl properties s well s linked to their functionl properties in dough systems. The objectives of this reserch were; to evlute the effects of brn source, inclusion level, nd brn size on wter bsorption nd rheologicl properties of whet flour dough systems of different strength, nd to study the lof volume, crumb texture, nd microstructure of the resulting bked products. 28

47 2.2 Mterils nd Methods Mterils Two whet vrieties of different bking strengths were used for ll experiments. Krl 92, hrd red winter (HRW) whet, ws obtined from KSU Foundtion Seed, Knss Stte University. Soft whet, combintion of club whet nd soft white whet vrieties ws obtined from the pilot mill in the Deprtment of Grin Science nd Industry. Stright-grde flours of Krl 92 (HRW) nd soft white (SW) whet vrieties were obtined by milling on Buhler model MLU- 202 experimentl mill (AACC Approved Method 26-21A). The HRW nd SW whet smples were tempered to 16% nd 14% moisture content, respectively, for 24 h before milling (AACC Approved Method 26-10A). HRW nd SW brn smples were collected from their respective milling. Originl (s is) brn smples were frctionted bsed on their prticle size to obtin corse ( μ) nd fine ( μ) brn sub-frctions using sieve stck of 1358, 1190, 1000, 900, nd 630 μ. Ech brn frction (s is, corse nd fine) ws dded to both bse flours t 0%, 5% nd 10% levels resulting in flour/brn systems summrized below: Bse flour/brn type* HRW/HRW HRW/SW SW/HRW SW/SW HRW/HRWc HRW/HRWf HRW/SWc HRW/SWf * : s is, c: corse, f: fine brn Objective To study the effect of different brn sources on bredmking performnce of hrd nd soft whet flours To study the effect of brn size on bredmking performnce of hrd whet flour Chemicl Composition All flour nd brn smples were subjected to compositionl nlysis. Moisture content ws mesured by the oven-ir method (AACC 44-15A). Protein content ws determined by the nitrogen combustion method using LECO Fp-2000 nitrogen/protein nlyzer using fctor of 6.25 to convert nitrogen to protein (AOAC ). Ash content ws mesured using the muffle furnce overnight method (AOAC ). Lipid content ws mesured using AOAC method (920.39). 29

48 2.2.3 Wter Sorption Behvior Wter sorption behviors of HRW nd SW brn smples (s is) were chrcterized by equilibrting them to wter ctivity (Aw) levels of 0.11, 0.33, 0.58 nd 0.75 using sturted slt solutions (lithium chloride, mgnesium chloride, sodium bromide nd sodium chloride, respectively). The moisture contents of equilibrted smples were determined nd sorption isotherms (moisture content vs. equilibrium Aw) were plotted Mixing nd Psting Behvior Frinogrph Flour nd wter were mixed in 50-g Frinogrph bowl for 20 min ccording to the stndrd procedure. AACC method ws used to determine Frinogrph consistency, wter bsorption (djusted to 14% MC), development time, stbility, mixing tolernce index (MTI), time to brekdown, nd Frinogrph qulity number Mixogrph The 10 g mixogrph (Ntionl Mnufcturing Co., Lincoln, NE, USA) ws used to study the mixing properties of dough systems s described by AACC Approved Method 54-40A. The flour nd wter were mixed in 10-g mixogrph bowl for 10 min ccording to the stndrd procedure. The pek time nd pek height vlues were obtined from the mixogrm curve. Pek development time ws used s bsis to determine optimum mix times for test bking MixoLb Dough mixing nd psting properties were studied using MixoLb (Chopin Technologies, Frnce) s described by ICC No. 173-stndrd method. According to the Chopin+ protocol, flour nd wter were mixed in 50-g MixoLb bowl for 45 min t constnt speed of 80 rpm. The mount of wter to be dded to HRW nd SW control flours ws previously determined from the frinogrms, nd then djusted to result in pek torque of 1.1 Nm. These wter ddition levels were then kept constnt to study the effect of brn ddition on mixing nd psting behvior of the bse flours. The resulting MixoLb curves were nlyzed for the following prmeters: Hydrtion cpcity, development time (C1), protein wekening s function of mechnicl work nd temperture (C2), strch geltiniztion nd pek viscosity (C3), 30

49 stbility or brek-down viscosity (C4), nd set-bck of geltinized strch (C5). In ddition, the ngles between scending nd descending curves α (protein brekdown), β (geltiniztion) nd γ (cooking stbility rte) were clculted. A detiled explntion of these MixoLb prmeters cn be found in Rosell et l. (2006) Test Bking The stright-dough procedure (AACC method 10-10B) using 100 g (flour weight) ws used. Ech dough system ws mixed in 100 g pin mixer (Ntionl Mnufcturing Co., Lincoln, NE, USA) using the optimized mixogrm wter bsorptions nd mix times s described in the method. Proofing ws performed t 30 ºC nd 95% reltive humidity for 40 min. Doughs were punched twice, nd then molded on specilized pup lof molder (Ntionl Mnufcturing Co., Lincoln, NE, USA). After molding, pnning, nd finl proofing, the doughs were bked for 24 min t 210 ºC in reel oven (Ntionl Mnufcturing Co., Lincoln, NE, USA). The smples were test bked in three replictes Bred Mcrostructure Lof volume ws mesured with clibrted rpe seed displcement meter (AACC Method 10-05) immeditely fter the loves were removed from the oven. Crumb structure of bked lves ws chrcterized using C-Cell imge nlyzing softwre nd equipment (Clibre Control Interntionl Ltd., UK). Loves were sliced using rotry disc food slicer. Imge nlysis ws performed on centrl slices tht were 1.5 cm thick. Imge nlysis prmeters (number of cells, verge cell wll thickness, cell dimeter) were used to compre crumb grin differences in bred smples Bred Microstructure Bred smples were scnned using high resolution desktop X-ry microtomogrph (XMT) (Skyscn1072, Artselr, Belgium) consisting of microfocus seled X-ry tube with spot size of 5 µm, n X-ry detector nd CCD-cmer (1024 x 024 pixels) with mximum smple field of view of mm. Bred specimens of pproximtely mm were crefully cut from the center slice using pir of shrp scissors while the bred ws frozen. The cut specimen ws then plced in cler plstic tube (15 mm dimeter) nd seled to prevent drying of the bred during scnning. The bred smples were dhered to double sided self- 31

50 dhesive disc to stbilize the specimen. Then the plstic tube ws secured on the rottble smple stge using double sided tpe. Scnning ws performed t 40 kv/248 µa t 20x mgnifiction (resulting in 13.7 µm/pixel resolution) t 1.35º scn steps with n exposure of 1.88 sec through 180º of rottion. Totl scnning time ws round 15 min/smple. The scnning process ws controlled by SkyScn 1072-TomoNT control softwre (version 3N.5). Sets of D rdiogrphs (shdow imges) per smple were rendered into 3-D objects using filtered bckprojection lgorithm by the NRecon reconstruction softwre (V1.5.1.) which ws subsequently digitlly sliced to crete hundreds of 2-D cross-sectionl imges tht were used for quntittive nlysis. A dynmic imge rnge of /mm (ttenuted coefficient) ws selected in the gry-scle histogrm to give n optimized cler reconstruction of the object. Imge nlysis ws performed using CT-nlysis processing nd nlysis softwre (CTAn, v.1.7). A 5 6 mm rectngulr region of interest (ROI) ws defined in the center of the bottom slice. This rectngulr section ws then interpolted cross the selected 600 slices with totl thickness of 8 mm to define the volume of interest (VOI). Imges were then converted from gryscle to pure blck nd white (binry imges) for nlysis. Gryscle imges hve pixels with vlues tht rnge from The rnge of 0-64 ws converted to pure blck, representing void res or gs cells. Pixels in the rnge of were converted to pure white to represent cell wll structures. The following morphometric prmeters were clculted for quntittive nlysis: Structure Seprtion: Averge of the thickness of the spces between solid structures (cell wlls) i.e. mesure of ir cell size (mm). Anlysis lso provides ir cell size distributions in the form of histogrms. Structure Thickness: Averge of the thicknesses of solid structure, used s mesure of verge cell wll thickness (mm). Anlysis lso provides cell wll thickness distributions in the form of histogrms. Percent void volume: Percentge of blck pixel counts (void res or gs cells) to totl pixel counts (blck + white pixels) Texture Profile Anlysis (TPA) A TA.XT Texture nlyzer (Texture Technologies Corp., Scrsdle, NY) equipped with 30 kg lod cell nd 1.5 cylindricl probe ws used. Two center slices ech 1.25 cm thick were 32

51 stcked together to result in smple thickness of 2.5 cm. The test ws conducted on three replictes of the center of ech smple using return to strt in compression mode, trigger force of 5 g nd strin of 40% with pre-test speed of 1.0 mm/s, test speed of 1.7 mm/s, relxtion of 5 sec nd post-test speed of 10.0 mm/s (AACC pproved method 74-09). The bred ws compressed twice to give two bite texture profile curve, from the texturl prmeters were obtined Sttisticl Anlysis The experiments were fctoril design. Results were nlyzed using nlysis of Vrince (ANOVA) in SAS (version 9.2) softwre (SAS Institute Inc., Cry, NC). Mens nd stndrd errors were obtined by using proc GLM procedure. One wy ANOVA ws performed using Tukey test procedure to determine differences mong tretments. Duplictes were prepred for the proximte nlysis nd rheologicl tests. Triplictes were prepred for test bking, crumb structure, TPA nd bred microstructure. 2.3 Results nd Discussion Composition nd Wter Absorption Behvior The physico-chemicl properties of Krl 92 (HRW) nd soft whet (SW) flours nd their respective brn frctions (s is, corse nd fine) re shown in Tble 2.1. HRW flour hs higher protein (17.81 vs 11.06%) nd slightly higher sh content (0.59 vs 0.46%) thn does SW flour. The lipid nd fiber content for HRW nd SW flours re not significntly different. HRW brn hs higher protein (22.28 vs 18.01%), higher lipid (3.97 vs 2.84%), higher sh (5.59 vs 5.48%), nd less fiber content (8.51 vs 8.74%) thn does SW brn. The difference in composition of HRW nd SW flours nd brns frctions might be ffected by severl fctors including whet clss, vriety nd growth conditions including environmentl fctors, loction nd griculturl prctices. Studies hve shown tht the vrince in bking qulities mong whet smples cn be ttributed to both genotype nd environmentl conditions (Hzen et l 1997; Bergmn et l 1998). As corse nd fine brn prticle sizes were obtined by sieving this could hve ffected their compositions. The HRW corse brn hs higher protein (21.67 vs 17.46%), lipid (3.31 vs 2.28%), fiber (12.42 vs 12.31%) nd sh (6.41 vs 6.27%) contents s compred to SW corse 33

52 brn. Similrly, HRW fine brn hd higher protein (23.18 vs 19.16%), lipid (4.24 vs 3.37%) nd sh (5.54 vs 5.09%) content except for fiber (9.65 vs 9.82%) content thn did SW fine brn. In comprison to the corse brn smple, fine brn hs higher protein nd lipid, nd lower fiber nd sh content thn does corse sizes of both HRW nd SW brns. The sieved fine prticles might be minly from shorts nd residul strch ttched to brn pieces which usully hve less fiber content thn do corse prticles (Blsi et l 1998). Becuse the originl brn (s is) ws combintion of corse nd fine brn prticles, the compositionl dt of s is brn re expected to lie between those of corse nd fine brn. This ws the trend observed in Tble 2.1 except for fiber content. This cn explined by the prticle size distribution in s is brn indicting high contribution of prticles smller thn the fine brn frction (i.e. <630μ). Peyron et l (2002) reported tht the brn prticle size, obtined from whet grins by milling is correlted with the extensibility of the outer grin lyers. The outer pericrp, which surrounds the outer grin lyers, is thin tissue wekly ttched to the intermedite lyer. Its frgile mechnicl nture, low extensibility nd fribility hve been reported to led mrked decrese in brn prticle size during milling. The intermedite lyer, contining different tissues (nucellr epidermis, test nd inner pericrp), hs complex nd heterogeneous structure. The test exhibits high plsticity, nd tends to brek into lrger prticle sizes during milling. Fribility of the inner pericrp hs been shown to be similr to tht of the outer pericrp, resulting in smller prticle size during milling. The strong ssocition between the leurone lyer nd the extensible intermedite lyer (Peyron et l 2002) ws reported to be responsible for the presence of leurone lyer mostly in intermedite sized brn prticles. This supports the observed differences in sh contents of corse nd fine brn smples s shown in Tble 2.1. Wter sorption behvior of HRW nd SW brn smples (s is) ws compred using equilibrium moisture content vs. wter ctivity plots t room temperture. The protein content of HRW brn ws observed to be higher thn tht of SW brn (Tble 2.1) which could imply tht HRW brn hs higher potentil to bsorb wter. However, there ws no significnt difference in sorption isotherms of HRW nd SW brn for ll wter ctivity levels s indicted by overlpping nture of the curves (dt not shown). Other chemicl constituents, such s the lipid content (3.97 vs 2.84%) nd dmged strch content of HRW nd SW brn should be tken into considertion to understnd the sorption isotherms. 34

53 2.3.2 Dough Mixing Properties The Frinogrph wter bsorptions nd mixing properties of HRW nd SW flours in the presence of HRW nd SW brn smples (0-10%) re shown in Figure 2.1. HRW bse flour hs higher wter bsorptions compred to SW flour, which ws n expected difference between strong nd wek whet flours. Generlly, high wter bsorption of flour is considered n indiction of good bking performnce. One reson could be tht high protein content leds to both good bking performnce nd higher wter bsorptions. The other reson is the incresed mount of dmged strch in the HRW flour, which, long with the protein content, is known to increse the wter bsorption cpcity (Bloksm 1972; Greer nd Stewrt 1959; Meredith 1966). Brn hs high protein content s compred to flour nd is expected to increse the wter bsorption cpcity of flour with brn dditions. In ll four combintions of flour/brn systems (i.e. HRW/HRW, HRW/SW, SW/HRW nd SW/SW) wter bsorptions incresed grdully with incresed level of brn dditions independent of brn type nd size. In generl, HRW nd SW brn dditions resulted in up to 5.7% higher wter bsorptions in HRW flour while the increse in wter bsorption rtes in SW flour ws up to 1.5%. HRW nd SW s is brns displyed n identicl wter sorption behvior. Their moisture content incresed from 7.5% to 16.0% s the storge reltive humidity (RH) incresed from 11 to 75%. Although the wter sorption behvior of two brn sources ws observed to be identicl, inclusion of HRW nd SW brns in bse flours hd differing degrees of influence on wter bsorptions of HRW nd SW flour. Addition of SW brn to HRW flour cused significntly higher wter bsorptions compred to HRW flour/hrw brn systems. This could be explined by the type nd level of interctions between different source of brns nd the strch, protein nd lipid components of the bse flour. SW brn hs less protein (18.0 vs. 22.3%), more lipid (2.8 vs 4.0%), more fiber (8.7 vs 8.5%) nd slightly less sh (5.5 vs. 5.6%) content thn HRW brn. Different whet cultivrs hve been reported to produce brn with different chemicl compositions nd to exhibit different hydrtion cpcities which inherently influence end product qulity nd crumb texture of breds (Nelles et l 1998; de Kock et l 1999). HRW nd SW brn dditions to HRW flour decresed the rrivl time nd stbility while incresing the mixing tolernce index (MTI). In HRW brn/hrw flour systems, while 5% brn ddition decresed the rrivl time slightly, brn ddition of 10 % resulted in lmost 3 min decrese in rrivl time. SW brn ddition to HRW flour resulted in 4.4 min shorter rrivl time 35

54 t 5% nd 5.2 min shorter t 10% ddition level. However, brn dditions to wek flour were found to be somewht beneficil leding to improved mixing properties in SW flour. Arrivl time nd stbility of SW flour incresed with incresed brn ddition, while the MTI vlues decresed significntly. HRW brn ws observed to improve such properties slightly more thn did SW brn. In SW flour systems rrivl time doubled t 10% brn ddition long with significnt increse in stbility vlues from 2.6 min to up to 4.5 min. MTI vlues decresed from 76.5 to 49.0 nd 42.0 with the ddition of 10% SW nd HRW brn, respectively. Figure 2.1 shows the wter bsorption nd mixing chrcteristics of HRW flour doughs with corse nd fine brn dditions. The wter bsorptions incresed for ll combintions of flour nd brn systems with corse nd fine prticle sizes for the resons discussed previously. In HRW flour/hrw brn systems, the corse nd fine brn prticle sizes resulted in up to 4.0 vs 4.2% increse in wter bsorptions while for HRW flour/sw brn systems, the increse in wter bsorption ws up to 5.5 vs 5.2%, respectively. Brn source ws observed to hve greter effect thn brn size. The HRW flour with SW corse nd fine brn dditions exhibited higher wter bsorptions s compred to HRW flour with HRW corse nd fine brn dditions. The trend for HRW flour/sw corse nd fine brn dditions is similr to HRW flour/sw s is brn wter bsorptions. The ddition of HRW nd SW corse nd fine brns to HRW bse flour decresed the rrivl time while incresed the stbility (Figure 2.1 b nd c). The mixing tolernce indexes (MTI) were lower (dt not shown) for ll corse nd fine brn dditions in HRW flours except for SW fine brn inclusion. The MTI incresed from 3.0 to 14.0 BU in HRW/SWf systems which ws much lower thn tht of HRW flour with brn s is dditions. The corser prticles size hd higher wter bsorption with the mgnitude of the effect incresing with the level of brn ddition. The decresed mixing stbility my be cused by the disruption of the gluten networks by the brn prticles. The effect on the gluten network might be greter for fine brn which hs more prticles thn does corse brn t equl brn substitution levels. The chnge in mixing behvior of dough systems cn be explined by the non-strch polyscchride (rbinoxyln) content of the frctions. Wng et l (2006) reported tht mong brn nd shorts frctions, totl pentosn nd wter unextrctble pentosn (WUP) content incresed in the order of corse brn > fine brn > shorts; while wter extrctble pentosn (WEP) content decresed in the order of shorts > fine brn > corse brn with incresing sh 36

55 content. Pentosns re known to hve n effect on the wter bsorption of dough. Wng et l (2002) reported tht WEP interfered with gluten formtion indirectly by competing for wter nd thus chnging conditions for gluten development. Similrly, the presence of WEP hs been reported to dely the development time of gluten, suggesting competition for wter during the first stge of dough formtion (Lbt et l 2002). The mixing properties of HRW nd SW flours with HRW nd SW brn dditions (0-10%) were lso studied using the Mixogrph. The Mixogrph wter bsorptions were correlted with Frinogrph wter bsorptions. The pek time nd pek vlue were higher for HRW bse flour s compred to SW bse flour, s expected. Usully, flours with good gs-holding properties nd mchinbility hve higher wter bsorptions, tke longer times to mix, nd hve better tolernce to over mixing thn do poor qulity flours. HRW flour doughs with HRW nd SW brn inclusions hd higher wter bsorptions which led to higher pek time. The pek time incresed up to 0.5% in the HRW flours with HRW brn inclusions (0-10%) while the pek time decresed up to 0.5% with SW brn inclusion. The pek time for SW flour/hrw brn systems incresed from min with the increse of brn level while the pek time decresed up to 1.2 % in SW flour/sw brn systems with the exception of the 5% SW brn inclusion level. There ws no significnt difference in pek vlues for ll combintions of HRW nd SW flour nd brn inclusion. In reltion to brn size, HRW flours with HRW corse nd fine brn inclusions (0-10%), the pek mixing time incresed up to 1.0% nd 0.5%, respectively Mixing nd Psting Properties Mixing nd psting properties of HRW nd SW bse flour doughs with nd without brn inclusion (0-10%) were studied using the MixoLb which mesures in rel time the torque (expressed in Nm) produced by pssge of the dough between the two kneding rms, thus llowing the study of the physic-chemicl behvior of the dough. The method mesures mixing behvior of dough smples subjected to both mixing nd controlled heting. Thus it hs the cpbility to mesure dough properties such s dough strength nd stbility nd strch psting properties. The initil stges of mixing involve the distribution of mteril nd the hydrtion of the flour leding to stretching nd lignment of the storge proteins nd ultimtely formtion of viscoelstic structure with gs retining properties. Thus the initil phse of MixoLb curves 37

56 provided cler informtion on the hydrtion cpcity nd dough development time of HRW nd SW bse flours with nd without brn. During this stge, n increse in the torque (C1) ws observed until mximum ws reched fter which the dough ws ble to resist the deformtion for some time. HRW bse flour hd higher hydrtion cpcity (93.1% vs 86.3%) nd longer development time compred to SW bse flour. The higher hydrtion cpcity nd development time of HRW flour were expected nd probbly the result of higher protein content of HRW flour. Effects of brn inclusion were studied t constnt hydrtion levels. Thus the increse in C1 torque vlues for brn contining dough systems indicted their higher hydrtion cpcity compred to control flours. Dough development time incresed s the brn level incresed in ll flours. The MixoLb dough stbility results were correlted with the Frinogrph stbility vlues. Dough stbility of HRW bse flour systems decresed slightly (from 11.7 min to 11.3 min) with 5% brn ddition. It further decresed to 8.9 min when 10% brn ws dded. However, in SW (weker) flour systems, brn ddition improved the mixing qulity by incresing the dough stbility from 4.5 min to min t 5-10% brn level. The next MixoLb mixing stge, where dough temperture grdully incresed from 30 to 90 C, resulted in decrese in torque (C2), which is ttributed to polymer softening due to mixing combined with heting. A decrese in the degree of this chnge ws observed with n increse in the ddition of HRW nd SW brn to bse flours. C2 vlues of HRW bse flours incresed from 0.57 Nm to 0.64 Nm (5% brn) nd 0.71 Nm (10% brn) indicting less gluten network wekening due to prolonged mixing nd temperture increse. This effect ws less pronounced for SW bse flours with n increse from 0.49 Nm to 0.54 Nm nd 0.60 Nm with 5 nd 10% brn ddition, respectively. Moreover, decrese in slope α (degree of network softening) with brn ddition ws observed. Temperture increse nd sher lso contribute modifictions of physico-chemicl properties of the strch known s geltiniztion nd psting. During heting, HRW nd SW bse flours contributed to higher strch psting pek (C3), better cooking stbility (C4) nd set-bck viscosity of strch (C5). With incresing levels of HRW or SW brn inclusions, C3, C4 nd C5 shifted to lrger vlues in prllel to with incresed C1 vlues due to competition for wter t constnt wter bsorption. In both HRW nd SW flour systems, pek viscosity (C3) vlues incresed by only Nm t 5% brn inclusion while the difference ws up to

57 Nm t 10% ddition. Similr trends were observed for C4 nd C5 vlues with grdul increse in torque redings with incresing levels brn dditions. In HRW flour systems, increses in C3 were ccompnied by reduction in C3-C4 difference indicting strch stbiliztion occurred with brn ddition. In SW flour systems n opposite trend ws observed. The bove results re consistent with studies exmining formulted bred doughs during mixing nd heting (Collr et l 2007), nd the effect of hydrocolloids on the thermo-mechnicl properties of whet dough (Rosell et l 2006) Bred Mcrostructure The lof volumes of HRW nd SW flour breds with nd without dded brn re shown in Figure 2.2. The HRW control bred hd higher lof volumes thn did SW bred, s expected. The control breds (0% brn) in generl hd higher lof volumes thn their brn dded counterprts. The lof volume of HRW breds decresed up to 26.5% with brn ddition nd significnt differences were observed with respect to source nd size of brn. The lof volume of HRW breds decresed from 1017 to 753 cc (26.0%) when 5-10% percent HRW ws brn dded while HRWf nd HRWc brn ddition cused decreses up to 20.8 nd 32.8%, respectively. SW brn ddition resulted in reltively less detrimentl effect on the lof volumes of HRW breds compred to breds contining HRW brn. The lof volume of HRW breds decresed in the rnge of % when 5-10% percent SW brn ws present. For HRW/HRW nd HRW/SW systems, corse brn ws observed to be the most detrimentl, followed by s is nd fine brn sizes. Smll prticle size seemed to be physiclly less disruptive to gluten network during dough development. The bsis for differences between HRW nd SW brn source dditions in HRW flours ws not cler nd will be further investigted. Brn ddition influenced the lof volume of SW bse flour breds only to limited extent. Brn dded t 5% level ws observed to be slightly beneficil s the lof volume incresed up to 4%, while 10% brn ddition cused round 8% decrese in the lof volume. Observed decreses in lof volumes with brn dditions re in greement with previous work (Shetlr nd Lymn 1944; Pomernz et l 1977; Dubios 1978; Shorgen et l 1981; Dreese nd Hoseney, 1982; Li et l 1989-c; Zhng nd Moore, 1999). Dreese nd Hoseney (1982) nd Ro 39

58 nd Ro (1991) reported tht ddition of brn to dough formultions generlly increses the level of wter required. In ddition to bred volume, crumb grin nd crumb texture re lso importnt qulity fctors in whet-bsed bred products. In this study, C-cell dt including numbers of cells, cell re nd wll thickness were used for mcrostructurl chrcteriztion of HRW nd SW breds (Figure 2.2 b, c, d). In these nlysis, number of cells reflects the number of discrete cells detected within the slice while cell dimeter reflects the corseness of crumb texture. At constnt lof volume, high number of cells my indicte fine crumb structure. Breds with lower lof volume were observed to hve fewer nd thicker cell wlls nd lrger cell size (Zghl et l 2001). Cell number decresed with incresed brn ddition irrespective of brn source or size. Overll, decresing cell numbers in combintion with incresing cell size nd cell wll thickness indicte colescence of ir cells during fermenttion nd/or bking resulting in low lof volumes Bred Microstructure Microstructurl fetures of HRW nd SW breds were studied through non-destructive 3D nlysis of bred specimens tken from the lof center using n x-ry microtomogrph (XMT). XMT nlysis provided quntittive informtion on void volume, cell size nd cell size distribution, cell wll thickness nd cell wll thickness distribution nd cell connectedness. Cell wll thicknesses nd ir cell size distributions in HRW nd SW breds with nd without HRW nd SW brn re shown in Figure 2.3. Brn ddition, irrespective of the source nd size, incresed the men cell wll thickness nd ir cell sizes nd produced grdul shift in distribution curves towrds higher vlues. Bubbles entrined in the HRW bse flour bred (no brn) were dispersed over nrrower size rnge thn were those in the brn-contining dough. Higher men bubble size vlues were observed in brn-contining dough smples probbly due to wekening effect of brn on the gluten network cusing gs bubble colescence. Incresed levels of brn ddition incresed the verge cell wll thickness of both HRW nd SW breds. These observtions were in ccordnce with the mcroscopic properties of the bred. Lof volumes decresed s the brn ddition incresed in HRW nd SW flours s discussed bove. Brn prticles interfere with gluten development during mixing which wekens the gluten network nd leds to gs bubble colescence during proofing nd bking. The cell wll thickness distribution of SW/HRW nd 40

59 SW/SW flour/brn systems hd lrger shifts towrds right s compred to HRW flours with HRW nd SW brn dditions. Consistent with the lof volume dt, SW brn ddition resulted in reltively less detrimentl effect on the void volume. HRW flour breds with SW brn hd reltively higher void volume, smller verge cell size nd cell wll thickness, which collectively indicte less cell colescence during proofing nd/or bking (Figure 2.4, b nd c). Brn type did not hve significnt effect on the microstructure of SW flour breds s the SW flour ws intrinsiclly lower in bredmking qulity flour due to its low protein content. No lrge differences were observed in bred microstructure with respect to brn size (Figure 2.4). All brn sizes cused significnt chnge in cell wll thickness nd cell size distributions towrds the lrger end of the scle. The lrger gs cells re likely the result of colescence cused by the instbility of bubble wlls. Overll, the effect of whet brn inclusion in HRW nd SW flours ws on increse in wter bsorption which further ffected the lof volumes. This indictes tht t lest some the dditionl wter required when brn is included is retined during bking. With incresed brn substitution, the externl ppernce of the loves becme corser. The observtions re in greement with Dreese nd Hoseney (1982), nd Ro nd Ro (1991) Bred Texture Qulity Figure 2.5 shows the texture profile nlysis (TPA) hrdness vlues for HRW nd SW breds with nd without brn. Hrdness of HRW bse flour breds ws lower thn tht of SW bred. This ws expected from the mcro- nd microstructurl differences detiled bove. SW flour breds hd poor texturl qulity nd lower lof volumes s compred to HRW flour breds. TPA hrdness incresed s the brn level incresed in both bse flours. With incresed brn ddition, the lof volumes decresed nd the incresed verge cell wll thickness nd ir cell size led to poor texture qulity. Both the brn source nd prticle size ffected the texture qulity of HRW flour breds. SW brn dditions (0-10%) to HRW flour were less detrimentl to texture s miniml or no increse ws found in hrdness vlues of HRW/SW flour/brn systems compred to control bred. SW brn ddition up to 5% hs improved the texture s indicted by slight decrese in hrdness vlues. As explined bove, SW brn prticle size hd higher wter bsorptions, higher resulting lof volumes with slightly less incresed cell wll thickness which 41

60 resulted in improved texture qulity in HRW/SW systems s compred to HRW/HRW systems. HRW/SWf flour systems hd higher hrdness vlues compred to tht of HRW/SWc which is in ccordnce with other studies. Collins (1983), Collins et l (1985), Collins nd Young (1986), nd de Kock et l (1999) reported tht fine whet brn gve denser crumb structure, nd smller lof volumes thn did corse brns. 2.4 Conclusions Addition of whet brn to bred dough formultions hd significnt effects on mixing properties, test bking nd crumb structure. Incresed brn content incresed wter bsorptions. HRW bse flour performed better compred to its counterprt SW both during dough mixing nd bking, which ws expected. In generl, brn ddition ffected the performnce of HRW flour negtively. However, SW nd HRW brn dditions into SW flour doughs systems slightly improved their mixing time s indicted by incresed mixing tolernce indices. SW brn ddition to HRW flour, resulted in reltively higher lof volumes nd better crumb texture compred to HRW/HRW flour/brn systems. Incresed brn inclusion incresed the bked crumb hrdness of both HRW nd SW flour systems. Brn prticle size ffected mixing nd bking properties. Corser prticles gve better mixing properties nd lrger lof volumes thn did finer prticles, but lso gve open textures t higher brn levels. Incresed brn dditions incresed the cell wll thickness of resulting breds bked from both HRW nd SW flour dough. Microstructurl nlysis of brn contining bred smples indicted grdul shift in ir cell size distributions towrds higher vlues. However, the experiments done using different prticle sizes produced results tht re contrdictory with some of the previously published studies. This spect is worthy of more detiled investigtion. 2.5 Acknowledgements This study ws supported by the USDA-NRI grnt. This rticle is published s contribution J of the Knss Stte University Agriculturl Experiment Sttion, Mnhttn, KS. The uthors would like to thnks Dr. Rebecc Miller of the Dept. of Grin Science nd Industry t Knss Stte University for test bking. 42

61 2.6 References AACC, Americn Assocition of Cerel Chemists Approved Methods, 10th ed. The Assocition, St Pul, Minnesot. Antoine, C., Peyron, S., Lullien-Pellerin, V., Abecssis, J., Rouu, X. (2004). Whet brn tissue frctiontion using biochemicl mrkers. Journl of Cerel Science, 39: Behll, K. D., Scholfield, D., Hellfrisch, J. (2006). Whole-Grin diets reduce blood pressure in mildly hypercholesterolemic men nd women. Journl of Americn Diet Assocition, 106(9): Bergmn, C. J., Gulberto, D. G., Cmpbell, K. G., Sorrells, M. E., Finney, P. L. (1998). Genotype nd environment effects on whet qulity trits in popultion derived from soft by hrd cross. Cerel Chemistry, 75: Blsi, D.A., Kuhl, G. L., Drouillrd, J.S., Reed, C. L., Trigo-Stockli, D.M., Behnke, K. C., Firchild, F. J. (1998). Whet middlings composition, feeding vlue, nd storge guidelines. Knss Stte University, August, Bloksm, A. H. (1972). Flour composition, dough rheology, nd bking qulity. Cerel Science Tody, 17: Burkitt, D. P. (1971). Epidemiology of cncer of the colon nd rectum. Cncer, 28: Collr, C., Bollin, C., Rosell, C. M. (2007). Rheologicl behvior of formulted bred doughs during mixing nd heting. Food Science Technologicl Interntionl, 13(2): Collins, T. H. (1983). Mking the best of brown bred. FMBRA Bulletin No. 1: Collins, T. H., Fern, T., Ford, W. (1985). The effects of gluten, fungl lph-mylse nd DATA ester in wholemel bred mde by CBP. FMBRA Bulletin No. 5: Collins, T. H., Young, V. L. (1986). Gluten fortifiction of brown flours used in Chorleywood Bred Process. FMBRA Bulletin No. 3: de Kock, S., Tylor, J., Tylor, J. R. N. (1999). Effect of het tretment nd prticle size of different brns on lof volume of brown bred. LWT-Food Science nd Technology, 32: Decker, E., Beecher, G., Slvin, J., Miller, H. E., Mrqurt, L. (2002). Whole grins s source of ntioxidnts. Cerel Foods World, 47(8): Dreese, P. C., Hoseney, R. C. (1982). Bking properties of the brn frction from brewer s spent grins. Cerel Chemistry, 59(2):

62 Erkkil, A. T., Lichtenstein, A. H., Jcques, P. F., Hu, F. B., Wilson, P. W. F., Booth, S. L. (2005). Determinnts of plsm dihydrophylloquinone in men nd women. British Journl of Nutrition. 93(5): Fridi, H. (1990). Appliction of rheology in the cookie nd crcker industry, in Dough Rheology nd Bked Products Texture. H. Fridi nd Fubion, J.M., eds. Vn Nostrnd, Reinhold, New York. Gllird, T., Gllgher, D. M. (1988). The effect of whet brn prticle size nd storge period on brn flvor nd bking qulity of brn/flour blends. Journl of Cerel Science, 8: Greer, E. N., Stewrt, B. A. (1959). Wter bsorption of whet flour: Reltive effects of protein nd strch. Journl of Science Food Agriculture, 10: Hzen, S. P., Ng, P. K. W., Wrd, R. W. (1997). Vrition in grin functionl qulity for soft winter whet. Crop Science, 37: Kntor, L. S., Vriym, J. M., Allshouse, J. E., Putnm, J. J. (2001). Choose vriety of grins dily, especilly whole grins: A chllenge for consumers. Journl of Nutrition, 131: Lbt, E., Rouu, X., Morel, M. H. (2002). Effect of flour wter-extrctble pentosns on moleculr ssocitions in gluten during mixing, LWT-Food Science nd Technology, 35(2): Li, C. S., Dvis, A. B., Hoseney R. C. (1989c). Production of whole whet bred with good lof volume. Cerel Chemistry, 66(3): Li, C. S., Hoseney, R. C., Dvis, A. B. (1989). Effects of whet brn in bred bking. Cerel Chemistry, 66(3): Li, C. S., Hoseney, R. C., Dvis, A. B. (1989b). Functionl effects of shorts in bredmking. Cerel Chemistry, 66(3): Meredith, P. (1966). Dependence of wter bsorption of whet flour on protein content nd degree of strch grnule dmge. New Zelnd Journl of Science, 9: Moder, G. J., Finney, K. F., Bruinsm, B. L., Ponte, J. G., Bolte, L. C., (1984). Bred-mking potentil of stright-grde nd whole-whet flours of Triumph nd Egle-Plinsmn V hrd red winter whets. Cerel Chemistry, 61: Montonen, J., Knekt, P., Jrvinen, R., Arom, A., Reunnen, A. (2003). Whole grin nd fiber intke nd the incidence of type 2 dibetes. Americn Journl of Clinicl Nutrition, 77(3): Nelles, E. M., Rndll, P. G., Tylor, J. R. N. (1998). Improvement 575 of brown bred qulity by prehydrtion tretment nd cultivr selection of brn. Cerel Chemistry, 75:

63 Pomernz, Y., Shorgen, M., Finney, K. F., Bechtel, D. B. (1977). Fiber in bred mking-effect on functionl properties. Cerel Chemistry, 54(1): Prentice, N., D Appoloni, B. L. (1977). High-fiber bred contining brewer s spent grin. Cerel Chemistry, 54(5): Ro, P. H., Ro, H. M. (1991). Effect of incorporting whet brn on the rheologicl chrcteristics nd bred mking qulity of flour. Journl of Food Science nd Technology, 28: Rosell, C. M., Collr, C., Hros, M. (2006). Assessment of hydrocolloid effects on the thermo mechnicl properties of whet using MixoLb. Food Hydrocolloids, 21: Shetlr, M. R., Lymn, J. F. (1944). Effect of brn on bred mking, Cerel Chemistry, 21: Vetter, J. L. (1998). Commercilly vilble fiber ingredients nd bulking gents. Americn Institute of Bking Technology Bulletin, 10(5): 1-6. Wng, M., Hmer, R. J., vn Vliet, T., Oudgenoeg, G. (2002). Interction of wter extrctble pentosns with gluten protein: Effect on dough properties nd gluten qulity, Journl of Cerel Science, 36(1): Zghl, M. C., Scnlon, M. G., Spirstein, H. D. (2001). Effects of flour strength, bking bsorption, nd processing conditions on the structure nd mechnicl properties of bred crumb. Cerel chemistry, 78: 1-7. Zhng, D., Moore, W. R. (1997). Effect of whet brn prticle size on dough rheologicl properties. Journl of Science Food Agriculture, 74: Zhng, D., Moore, W. R. (1999). Whet brn prticle size effects on bred performnce nd qulity. Journl of Science Food Agriculture, 79:

64 Tble 2.1Compositionl nlysis of HRW nd SW Flour nd brn Chemicl composition (%) Flour smples Brn smples HRW SW HRW SW HRWc SWc HRWf SWf Protein ± 0.02 e ± 0.01 g ± 0.02 b ± 0.03 e ± 0.07 c ± 0.01 f ± ± 0.17 d Lipid 1.04 ± 0.03 g 1.04 ± 0.01 g 3.97 ± 0.02 b 2.84 ± 0.03 e 3.31 ± 0.01 d 2.28 ± 0.02 f 4.24 ± ± 0.03 c Crude fiber 0.04 ± 0.01 f 0.05 ± 0.06 f 8.51 ± 0.09 e 8.74 ± 0.01 d ± ± ± 0.01 c 9.82 ± 0.07 b Ash 0.59 ± 0.01 f 0.46 ± 0.01 g 5.59 ± 0.02 c 5.48 ± 0.01 d 6.41 ± ± 0.03 b 5.54 ± 0.02 c 5.09 ± 0.03 e *Protein (Flour)= n x 5.27 fctor *Protein (brn)= n x 6.25 fctor *HRW= Hrd Red Winter, SW= Soft Whet, =s is, c=corse, f= fine Dt re men of duplictes ± stndrd devition. Vlues within the row with the sme letter re not significntly different from ech other t p

65 Tble 2.2 MixoLb mixing nd psting profile prmeters of Hrd Red Winter (HRW) nd Soft White (SW) flour doughs in the presence of brn HRW flour No brn +5% HRW +10% HRW +5% SW +10% SW Wter bsorption (% db) Amplitude (Nm) 0.07 ± 0.01 bc 0.09 ± 0.00 bc ± 0.01 bc 0.09 ± ± 0.01 bc Stbility (min) ± 0.99 b 12.1 ± ± 0.11 cd ± 1.27 bc 8.43 ± 0.71 de C1 (Nm) 1.15 ± 0.01 e 1.28 ± 0.00 bc 1.38 ± ± 0.01 b ± 0.02 C2 (Nm) ± 0.01 ef ± 0.04 b 0.71 ± ± 0.01 bc ± 0.01 C3 (Nm) ± 0.01 e 1.89 ± 0.03 d 1.99 ± 0.00 b 1.85 ± 0.03 e 1.92 ± 0.00 cd C4 (Nm) ± 0.04 d ± 0.02 bc 1.93 ± 0.01 b 1.84 ± 0.06 c ± 0.01 bc C5 (Nm) 2.65 ± 0.00 f 2.83 ± 0.06 de ± 0.05 b ± 0.06 de ± 0.01 de Alph (-) ± ± ± ± ± 0.10 Bet (-) ± 0.02 b ± ± 0.06 b ± 0.06 b ± 0.01 b Gmm (-) ± 0.02 b ± ± ± b ± 0.00 b SW flour No brn +5% HRW +10% HRW +5% SW +10% SW Wter bsorption (% db) Amplitude (Nm) ± ± 0.01 b ± 0.01 bc ± 0.01 bc ± 0.01 c Stbility (min) 4.49 ± 0.65 g 7.41 ± 0.16 ef 7.66 ± 0.06 ef 6.6 ± 0.66 f 6.71 ± 0.09 f C1 (Nm) 1.21 ± 0.04 de 1.18 ± 0.01 de ± 0.05 b ± 0.04 cd ± 0.04 b C2 (Nm) 0.49 ± 0.00 g 0.54 ± 0.01 f ± 0.01 de 0.54 ± 0.01 f ± 0.04 cd C3 (Nm) ± 0.01 c 1.99 ± 0.01 b 2.07 ± ± 0.00 c ± 0.02 b C4 (Nm) ± 0.01 bc ± 0.02 bc ± ± 0.01 c 1.85 ± 0.08 C5 (Nm) 2.78 ± 0.01 e ± 0.06 bc ± ± 0.03 ef 2.88 ± 0.06 cd Alph (-) ± ± ± ± ± 0.00 Bet (-) 0.37 ± 0.01 b 0.36 ± 0.07 b ± 0.00 b ± 0.03 b 0.37 ± 0.00 b Gmm (-) ± 0.01 b ± 0.01 b ± 0.00 b ± 0.03 b ± 0.01 b Vlues within the row with the sme letter re not significntly different from ech other t p Plese refer to the Mterils nd Methods for the description of the prmeters listed. 47

66 Development time (min) Wter Absorption (%) g fg de ef bcd e bc ef cd cd cd b c b bc % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 50 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW () HRW flour SW flour b bc bc b bc bc bc bc c bc bc b b b 0 0% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 0 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW (b) HRW flour SW flour 48

67 Stbility (min) bc de f bcd ef b bc ef def cd bc b b b b (c) 0 0% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf HRW flour 0 0% 5% 10% 5% 10% No brn HRW SW Figure 2.1 Dough development properties of Hrd Red Winter (HRW) nd Soft White (SW) flour doughs in the presence of brn. () Wter bsorption, (b) dough development time, (c) stbility. : s is, c: corse, f: fine Vlues within the HRW flour compred to no brn with the sme letter re not significntly different from ech other t p Vlues within the SW flour compred to no brn with the sme letter re not significntly different from ech other t p SW flour 49

68 Number of cells Lof volume (cc) bc bc bc c bc bc b b bc b bc bc b b b b % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 0 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW () HRW flour SW flour b bcd bcd d bcd cd b bcd bcd bcd bc bcd % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 0 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW (b) HRW flour SW flour 50

69 Cell wll thickness (mm) Cell size (mm) b b b b b b b b b b b % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 1.2 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW (c) HRW flour SW flour c bc bc bc bc bc bc bc bc b bc bc (d) % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf HRW flour % 5% 10% 5% 10% No brn HRW SW Figure 2.2 Mcrostructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in the presence of brn. () Lof volume, (b) totl number of cells, (c) cell size, (d) cell wll thickness : s is, c: corse, f: fine Vlues within the HRW flour compred to no brn with the sme letter re not significntly different from ech other t p Vlues within the SW flour compred to no brn with the sme letter re not significntly different from ech other t p 0.05 SW flour

70 () (b) Figure 2.3 Microstructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in the presence of brn. () Air cell size distribution, (b) cell wll thickness distribution. 52

71 Avg cell size (mm) Void volume (%) bc bc bc bc bc bc bc bc c b bc bc % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 50 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW () HRW flour SW flour % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 0.0 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW (b) HRW flour SW flour 53

72 Avg cell wll thicknesss (mm) c bc b bc b bc bc b bc bc bc bc b b b b (c) % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf HRW flour % 5% 10% 5% 10% No brn HRW SW SW flour Figure 2.4 Microstructure of Hrd Red Winter (HRW) nd Soft White (SW) flour breds in presence of brn. () Void volume, (b) verge cell size, (c) verge cell wll thickness : s is, c: corse, f: fine Vlues within the HRW flour compred to no brn with the sme letter re not significntly different from ech other t p Vlues within the SW flour compred to no brn with the sme letter re not significntly different from ech other t p

73 Hrdness (g) b b b b bc bc b bc bc b bc c bc bc c % 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 5% 10% 0 0% 5% 10% 5% 10% No brn HRW HRWc HRWf SW SWc SWf No brn HRW SW HRW flour SW flour Figure 2.5 Texture Profile Anlysis (TPA) hrdness of Hrd Red Winter (HRW) nd Soft White (SW) in the presence of brn : s is, c: corse, f: fine Vlues within the HRW flour compred to no brn with the sme letter re not significntly different from ech other t p Vlues within the SW flour compred to no brn with the sme letter re not significntly different from ech other t p

74 Chpter 3 - Effect of brn frctions of vrying ntomicl origin nd size t vrying replcement levels on dough development, nd smll nd lrge deformtion rheologicl properties Abstrct The effect of dding brns of different prticle size nd ntomicl origin in two whet flours of different bredmking qulity were studied. Hydrtion behvior, mixing nd dough development using empiricl rheologicl methods, s well fundmentl rheology t smll nd lrge deformtion rtes were explored. The results reveled tht the rheologicl behvior of brn enriched doughs depend on type of bse flour (strong nd wek), brn type, brn replcement level (0. 5, 10%), nd the dough development protocol (constnt versus optimum wter bsorption). Addition of brn did not ffect dough hydrtion in excess wter s mesured by wter solvent retention cpcity, while the wter bsorption during dough development increse significntly independent from the brn type nd replcement level. In generl, dely in dough development time of strong whet flour ws observed in the presence of brn. Wek flour doughs benefited from inclusion of brn s inherently low pek height nd stbility of these doughs improved in the presence of brn. Mechnicl spectr provided set of rheologicl prmeters including storge modulus (G ), loss modulus (G ), complex modulus (G*), tngent delt (tn δ), nd complex viscosity (η*) in the liner viscoelstic rnge. Temperture sweeps indicted slight decrese in G nd G" until round C. In the sme temperture rnge, presence of brn incresed the moduli of composite four compred to tht of the control flours, however, upon the onset of geltiniztion this difference diminished completely nd resulted in not significnt differences in pek G nd pek G vlues. Creep complince prmeters indicted tht both brn source nd brn replcement hd significnt effect on mximum complince (Jmx) nd elstic complince (Je). In generl, Jmx vlues of composite flour doughs were lower thn tht of control dough indicting tht doughs in the presence of brn exhibit greter resistnce, show smller creep strin thn their counterprt. Finlly, the brn type ffected unixil extensionl properties, mximum resistnce (Rmx) nd elsticity (E), significntly independent from the type of bse flour. 56

75 3.1 Introduction Whet flour dough is composite, incompressible, viscoelstic, soft-solid mteril with complex rheology. It is considered s hydrted protein network tht behves nonlinerly during lrge deformtions (Tnner et l 2008). Gluten protein is mde up of glutenin nd glidin proteins of different moleculr weights, nd the entnglements of these proteins during mixing nd their subsequent interction with strch polymers hve the gretest effect on the finl bred qulity (Bloksm 1990). Strch grnules in the protein network of dough bsorb wter nd swell t tempertures below its geltiniztion temperture. Above the geltiniztion temperture (i.e. during bking), the strch grnules continue uptke of wter until grnules tht re fully hydrted rupture nd increse the dough viscosity by forming strch network (Olkku nd Rh 1978). Lipids ntive to the whet flour cn ffect the strch geltiniztion temperture by complexing with mylose to inhibit swelling, thereby incresing strch geltiniztion temperture (Morrison 1995). Along with components of flour, processing conditions re importnt for bred qulity. The purpose of determining dough rheology is to hve better control over ech processing stge s well s over the finl products. This cn be ccomplished by relting rheologicl behvior to predict functionlity during mixing, sheeting, nd bking (Dobrszczyk nd Morgenstern 2003). By understnding how ech component of dough contributes to the overll mteril properties, it becomes possible to mnipulte the dough nd get consistent, desirble results (vn Vliet et l 1992). The production of good qulity bred requires blnce of three requisite rheologicl properties: Extensibility, viscosity, nd strin hrdening. Extensibility refers to the dough s bility to stretch (lengthen) without rupture, viscosity is the resistnce to flow. Strin hrdening is more complex property; it is the increse of stress t rte lrger thn proportionl to the strin rte (vn Vliet et l 1992). In other words, strin hrdening is the bility of cell to undergo bixil extension nd not rupture nd it hs lrge influence on the stbility of gs cells (Sron nd McRitchie 2009). Extensibility must persist throughout bking to minimize gs cell membrnes from frcturing premturely. Dough viscosity must be high enough to rrest gs cell scension (Bloksm 1990b), nd strin hrdening must surpss certin level to ensure proper retention of gs cells tht expnd during fermenttion nd bking. 57

76 Viscoelsticity describes rheologicl behvior combining tht of viscous liquid nd n elstic solid. Dough viscoelsticity hs gret influence on the dough mchinbility, texture chrcteristics, nd finl product stbility (Uthykumrn et l 2000). Viscoelstic behvior hs been ttributed minly to the gluten protein frction of dough. A gret number of concurrent processes during mixing nd resulting gluten network development hve been proven to ffect the dough performnce (Cornec et l 1994; Dobrszczyk nd Morgenstern 2003; Song nd Zheng). Rheologicl tests hve been devised tht ttempt to simulte the bredmking processing in order to revel how flow behvior reltes to mteril (dough) composition, s well s describing mechnicl properties of the dough for qulity control purposes. Dt obtined from rheologicl chrcteriztion cn be useful in the development of food products through ingredient selection, product improvement nd optimiztion, choosing nd optimizing mnufcturing techniques, nd developing pckging nd storge methods. The use of both smll nd lrge deformtion mesurement of dough is criticl for complete understnding of dough rheology. Lrge deformtion methods simulte stress-strin conditions found in commercil processing nd therefore cn disclose food texturl properties under those conditions s well s indicte finl bredmking qulity (Dobrszczyk nd Morgenstern 2003; Dvidou et l 2008). Smll deformtion techniques re most useful for mesuring viscoelstic properties of dough (Angioloni nd Collr 2009). Empiricl descriptive techniques re generlly more ccepted thn fundmentl method. Although fundmentl rheometry provides gret del of importnt knowledge in dough rheology, these fundmentl techniques re often considered to be timeconsuming nd lbor intensive. Good bking performnce is dependent on severl rheologicl properties of whet flour doughs. In the whole bred mking process, bkers ssess the properties of the dough t vrious process stges. The ssessment of the dough properties is done using specilized equipment such s the Frinogrph, Mixogrph, Extensogrph nd Alveogrph. These instruments imitte the deformtion experienced by the dough during processing nd provide mesurements of the physicl properties of the dough. These mesurements re empiricl nd generlly give good correltions with bred mking performnce. However, the results cnnot be interpreted in terms of mteril properties (Menjivr 1990). Fundmentl rheologicl methods re used to chrcterize those mteril properties. Severl studies hve been reported on smll deformtion 58

77 tests for whet flour doughs nd correlted results with bredmking qulity. Dynmic testing hs become powerful pproch for exmining structure nd fundmentl properties of whet flour doughs nd proteins becuse of its sensitive response to the structure vritions (Tronsmo et l 2003). Severl uthors hve studied the rheologicl properties (storge modulus, G ; loss modulus, Gʺ; nd loss tngent, tn δ) of flours of different strengths. The good qulity flours hve lower loss tngent vlues when dynmic rheology testing is performed (Miller nd Hoseney 1999). In spite of the lrge mount of informtion vilble on the empiricl nd fundmentl rheologicl properties on whet doughs nd gluten, very little informtion is vilble on smll deformtion tests on brn substituted flour doughs. Previous work reported generl deteriortion occurs in dough rheologicl properties when brn is dded (Shetlr nd Lymn 1944; Pomernz 1977; Li et l 1989; Zhng nd Moore 1997). Brn ddition cuses reduction of dough strength especilly t high brn levels. Most of the reserch hs been done on flourwter doughs; not much informtion is vilble on the effect of the brn prticle size on dough using fundmentl rheology. Treted nd untreted brn flour doughs studied using dynmic oscilltory tests found tht G vlues were higher thn tht of control flour dough (Amirkveei et l 2009). The loss tngent of untreted brn flour doughs ws higher thn tht of control flour doughs indicting tht untreted brn wekens the gluten mtrix while the treted brn strengthens the protein mtrix to some extent (Amirkveei et l 2009). Bonnnd-Ducsse et l (2010) studied the effect of whet dietry fiber frctions from strchy endosperm, leurone lyer nd brn on bred dough development nd rheologicl properties. The results showed tht whet dietry fiber frction in the dough led to decrese in mixing pek time nd to n extent to n increse of pek bndwidth. Similr pek time results were observed decrese in pek time with incresing levels of whet dietry fiber dded to the flours (Jelc nd Hlynk 1971; Courtin et l 1999). Smll deformtion tests found increses in viscoelstic moduli with incresed fiber content. This could be explined by two hypotheses: (i) gluten nd fiber compete for wter in the mixing process, or (ii) the fiber cts s filler in the viscoelstic network (Izydorczyk et l 2001; Wng et l 2003; Uthykumrn et l 2002). Peressini et l (2009) evluted the influence of soluble dietry fibers such s inulin on the rheologicl nd bredmking properties of whet doughs. The ddition of inulin ffected the 59

78 viscoelstic properties indirectly by chnging wter-flour rtios or directly by ffecting dough elsticity. The sme reserchers studied the viscoelstic properties of doughs t constnt wter bsorption becuse the use of Frinogrph optimum bsorptions does not llow decoupling the effects of hydrtion nd fiber. Storge modulus decresed s the mount of inulin in the whet doughs incresed. These results re in ccordnce with studies conducted by Rouillé et l (2005). Ahmed et l (2015) studied the mechnicl rigidity of β-glucn concentrte supplemented doughs. Rigidity ws strongly influenced by the concentrte prticle size nd solid-to-wter rtio. Their studies suggested tht lrge prticles occupy more spce during ggregtion thn do smll prticles due to less efficient prticle pcking nd tht this leds to more volume occupied by lrge prticles nd concomitnt increse in flow resistnce. Solid-like behvior grdully decresed with incresing dough wter content. The finest prticle dough showed the mximum strin during creep test which confirms its viscoelstic nture. Creep tests exhibited more pronounced effect of β-glucn on dough behvior compred to the oscilltory mesurements. Schimele et l (2012) nlyzed the influence of substituting refined whet flour by whet brn nd whole grin whet flour on dough rheologicl properties nd pn bred qulity chrcteristics. Whet brn dded composite flours or whole grin whet flours incresed wter bsorption nd resistnce to extension nd decresed stbility, extensibility nd pek viscosity. Although some recent studies hve demonstrted the effects of different dietry fibers on the rheologicl properties of the dough, little hs been done on the influence of its prticle size on rheologicl properties. The objective of this study ws to evlute the effects of different whet brn prticle sizes nd sources on smll nd lrge deformtion rheologicl properties of dough systems of different protein strength. 3.2 Mterils nd Methods Whet Flour nd Brn Bse flours: Hrd red winter (good bredmking) whet flour ws supplied by King Arthur Flour, Norwich, VT, USA. The flour contined 11.6 % (14% mb) protein, 0.48 % (14 % mb) sh nd this flour is referred s strong (S) flour herefter. The whet flour ws diluted with 100% pure whet strch (MGP Ingredients, Inc., Atchison, KS) to obtin flour of 10 % protein. This is referred s wek (W) flour. 60

79 Brn smples: Hrd red winter (HRW) brn ws obtined from the Hl Ross Pilot Mill in the Deprtment of Grin Science nd Industry, Knss Stte University, Mnhttn, KS. Sieve nlysis indicted tht 99.50% (by weight) of brn prticles were below 2920 µm. Two ctegories of whet brn smples were prepred on the bsis of (i) sme ntomicl origin but different prticle size, nd (ii) sme prticle size but different ntomicl origin s explined in Tble 3.2 Clssifiction of the brn smples. As is whet brn ws divided into four equl portions. Extreme cre ws tken through dequte mixing to minimize segregtion of brn nd thus provide homogeneity. Ech portion ws pssed through Fitz mill (Fitzptrick, Elmhurst, IL, USA) using four different screen sizes so s to obtin brn smples of sme ntomicl origin but different prticle size (Ctegory-I, Tble 3.2). Screen sizes were selected to provide pproximtely 1000 µm intervls (i.e. 3000, 2000, 1000 µm). The fourth screen size (140 µm ws chosen to reflect the prticle size cut off for stright grde whet flour. In order to obtin brn smples of sme prticle size but different ntomicl origin (Ctegory-II, Tble 3.2) s-is brn ws sieved nd collected in three sub-frctions: µm, µm nd below 977µm.The first two ctegories were pssed through Fitz mill (Fitzptrick, Elmhurst, IL, USA) equipped with 977 µm screen. Ech brn sub-frction A, B, C, D, E, F, G ws dded seprtely to both bse flours (S nd W) t 5% nd 10% replcement Experimentl Design A full fctoril experimentl design ws used to test the prmeters listed below: 2 bse flours : Strong (S) nd wek (W) flour 7 brn frctions : A, B, C, D nd E, F, G. 2 replcement levels : 5 nd 10% (flour bsis) + control (no brn) 2 dough development protocols : Optimum nd constnt wter bsorption (WA) Brn nd Flour Chrcteriztion Proximte Anlysis of Flours nd Brn Sub-frctions Moisture content ws mesured by the oven-ir method (AACC 44-15A). Protein content ws determined by nitrogen combustion using LECO Fp-2000 nitrogen/protein nlyzer nd 61

80 fctor of 6.25 to convert nitrogen to protein (AOAC ). Ash content ws mesured by the muffle furnce overnight method (AOAC ). Fiber nd lipid contents were mesured using AOAC methods ( nd respectively). Anlyses were performed in duplicte Solvent Retention Cpcity AACC method ws used to mesure the solvent retention cpcity (SRC) of flour nd brn smples lone, nd tht of composite flours t 5 nd 10% replcement levels. Test results were reported s percentges of the mss of the flour gel fter exposure to the solvent divided by the originl flour weight. Anlyses were performed in triplicte Prticle Size Men prticle size nd prticle size distribution were mesured using Beckmn Coulter LS Lser Diffrction Prticle Size Anlyzer (Beckmn-Coulter, Inc., Mimi, FL). The flour nd brn smples were plced into the lod cell until it ws pproximtely 2/3 full. The Torndo Dry Powder Dispersing ttchment ws used to lod up the smple nd mesure its prticle size. Anlyses were performed in duplicte. Prticle size distributions were expressed s of d-vlues (d10, d25, d50, nd d90) corresponding to the mximum dimeters of 10%, 50%, nd 90% of the prticles, respectively (in % of totl volume) Dough Development Frinogrph The Frinogrph (AACC Method 54-21) ws used to determine wter bsorption (djusted to 14% MC), development time, stbility, mixing tolernce index (MTI), time to brek down, nd Frinogrph qulity number of the brn sub-frctions contining whet flour doughs. Anlyses were performed in duplicte Mixogrph The 10 g mixogrph (Ntionl Mnufcturing Co., Lincoln, NE, US) ws used to study the mixing properties of the flour doughs s described s AACC Method 54-40A. Optimum wter bsorption vlues obtined for control flours (S nd W flour) were kept constnt nd used for ll 5 % nd 10% brn substitutions to study the effect of brn replcement level t constnt 62

81 wter bsorption. Anlyses were performed in duplicte. The pek development time nd pek height were reported for ll brn substituted doughs. A series of mixogrms were nlyzed to determine the optimum wter bsorption of ech brn substituted flour. Optimum bsorption nd time to rech pek were reported. Pek development time ws used to determine mixing time for ech smple. Anlyses were performed in duplicte Dough Rheology (Smll Deformtion) A stress-controlled rheometer (Stress Tech HR, ATS Rheosystems, Bordentown, NJ, US) equipped with 40 mm prllel plte were used. Plte temperture held constnt t 30 C, The gp between the two pltes ws set t 2.1 mm Smple Preprtion Dough smples were prepred by mixing 10 g of brn substituted flour in mixogrph pin mixer (Ntionl Mnufcturing Co., Lincoln, NE, US) t optimum nd constnt wter bsorption levels with vrible mixing times. Two smll blls (pproximtely 3.8 g ech) were mde from ech mixed dough smple, plced on prchment pper, nd rested in humidity nd temperture controlled cbinet set t 30 C nd 75% RH for 15 min. After resting, the dough piece ws plced gently on the bottom plte of the rheometer using sptul to void excess deformtion. The rheometer ws lowered to gp of 2.2 mm, nd the excess smple ws trimmed. Trimming ws done with shrp sptul in downwrd motion to void excess deformtion of the dough while cutting it even with the edge of the top plte. Minerl oil ws used to keep the edges of the dough from drying. After trimming, the rheometer ws lowered to the trget gp of 2.1 mm, nd smple ws llowed to rest for 15 min prior to testing. The dough rheology ws mesured by strin sweep, frequency sweep, temperture sweep, creep recovery nd stress relxtion testing Stress Sweep (Liner Viscoelstic Region) Stress sweeps were performed to determine the liner viscoelstic region (LVR) of the doughs. LVR ws determined for the smples t the extremes of 0% (i.e. control) nd 10% brn replcement. Smples were prepred, rested nd loded on rheometer plte for testing. The instrument operted with gp of 2.1 mm gp t 30 C with smple loding method to gp. 63

82 The mximum loding force on the smple ws 3.539E+4 P. The testing proceeded when force ws below 1.770E+4 P. The finl equilibrium time ws 15 min, nd ll settings for number of mesurements 1, mesurement intervl t 2.000E+1 s, constnt frequency t 1.0 Hz, dely time of 10 sec, integrtion period 1.00, FFT size t 512, nd strin rnge between % nd 10 % Frequency Sweep Frequency sweeps were performed t rnge from 0.1 to 100 Hz with constnt stress of 30 P t 30 C (s determined through stress sweep test described in section ), finl equilibrtion time 15 min, number of mesurements 1, mesurement intervl 2.000E+0 s, dely time 10 seconds, integrtion period of 1.00, FFT size t 512. Anlyses were performed t lest in triplicte with seprte dough btches for ll brn-substituted flours. Elstic (storge) modulus (G ), viscous (loss) modulus (Gʺ), complex modulus (G*), sher stress, phse ngle (δ) nd complex viscosity (ɳ*) were collected Temperture Sweep Temperture sweeps were performed from C for 2400 sec t heting rte of 1.5 C/min with constnt stress of 30 P nd frequency 1.0 Hz. The temperture sweep tests were performed with the uto tension smple loding method, nd trget tension of 8.85E+3 P. The finl equilibrtion time ws 15 min, dely time of 1.000E+0 sec, integrtion periods 1.00, Stress 30 P, FFT size 512. Temperture sweeps were performed t optimum wter bsorption levels for strong nd wek flours nd the brn sub-frction substituted flours. Anlyses were done in duplictes with seprte dough btches. Flour doughs were compred using dt for elstic modulus (G ), viscous modulus (Gʺ), complex modulus (G*), sher stress, phse ngle (δ) nd complex viscosity (ɳ*) Dough Rheology (Lrge Deformtion) Unixil Extensionl Properties Brn substituted flour doughs were nlyzed for their unixil extensionl properties using the Kieffer rig extensibility test method using TA.XT2 texture nlyzer (Stble Micro Systems, UK). Dough smples were prepred in pin mixer using Mixogrph prmeters. The dough ws plced into Teflon-coted block to prepre dough strips ccording to the method of 64

83 Kieffer t l (1981, 1998), nd rested for 45 min t 30 C, 75% RH dough strips from ech dough smple were tested t extension speed of 10.0 mm/sec. The prmeters recorded were mximum resistnce to extend the developed dough (Rmx) nd extensibility (E) until dough rupture Creep Recovery Creep recovery mesurements were performed on brn substituted flour doughs t temperture of 30 C nd sher stress of 50 P over creep time of 1200 sec nd recovery time of 1200 sec. The finl equilibrium time ws 15 min, nd the set prmeters were; number of mesurements 1, mesurement intervl 2.000E+1 sec, nd inerti compenstion of 100 %. Anlyses were performed t lest in duplicte with seprte dough btches for strong nd wek flour with brn substitutions t optimum wter bsorption levels. Dt for mximum creep strin (Jmx), mximum recovery strin (Je) nd percent recovery (Je/Jmx), recovery strin expressed s percent of mximum creep strin, were collected Stress Relxtion Stress relxtion tests were performed in non-liner viscoelstic region with strin of 5% for 250 sec t constnt temperture of 30 C. The set prmeters for the test were; number of mesurements 1, mesurement intervl 2.000E+1 sec, relxtion strin rise time sec, mesurement intervl sec. Duplicte doughs were tested. Relxtion modulus G(t) ws collected nd nlyzed to compre the effect of brn prticle size on both strong nd wek flour t optimum wter bsorption Sttisticl Anlysis A full fctoril experimentl design ws used to nlyze the rheologicl properties of whet dough with or without brn of different prticle sizes. Results were nlyzed using Anlysis of Vrince (ANOVA) using SAS progrm (Sttisticl Anlysis System Version 9.2). Mens nd stndrd errors were obtined by the proc GLM procedure. One wy ANOVA ws performed using Tukey test procedure to determine differences mong tretments. Duplictes were prepred for the proximte nlysis nd rheologicl tests. Triplictes were prepred for unixil extension tests 65

84 3.3. Results nd Discussion Physicl nd Chemicl Properties of Bse mterils Proximte Anlysis Hrd red winter (HRW) whet flour (King Arthur Flour, Norwich, VT, USA) ws used s the bse of the strong flours with good bredmking qulity. The flour contined 11.6 % protein nd 0.48 % sh t 14% moisture bsis. This whet flour ws diluted with 100% pure whet strch to obtin flour t 9.6 % protein, which designted wek flour with inferior bredmking qulities (Tble 3.1). Brn of HRW whet ws obtined ws used s the strting mteril for cretion of two ctegories of brn smples. As explined in section s is brn ws divided into four frctions nd pssed through Fitz mill using four different screen sizes to obtin brn smples of sme ntomicl origin but different prticle size t prticle size cut off points of round 3000, 2000, nd 1000 µm. The lst portion ws forced to pss through 140 µm screen to mtch the prticle size cut off of stright grde whet flour. In order to obtin brn smples of sme prticle size but different ntomicl origin s-is brn ws first sieved nd collected in three sub-frctions: µm, µm nd below 977µm.The first two ctegories of these brns were pssed through Fitz mill (Fitzptrick, Elmhurst, IL, USA) using 977 µm screen (Tble 3.2). The proximte composition, men prticle size nd prticle size distribution of these seven brn smples (A, B, C, D, E, F nd G) re presented in Tble 3.3 nd Figure 3.1. Prticle size: Sieve nlysis indicted tht 99.50% (by weight) of originl brn (s is) ws below 2920 µm. Prticle size nd size distribution nlysis indicted tht brn A hs the highest men prticle size (1189 µm), s expected. 90% of brn A prticles were below 1663 µm. This ws closely followed by brn B with men prticle size of 1097 µm, where 90% of prticles were below 1620 µm. Brn C hs much lower prticle size (~ 666 µm). The lst frction of ctegory-i, brn D, hs men prticle size of ~ 109 µm, nd 90% of prticles were below 216 µm. Two of the Ctegory-II brns (E nd F) hve men prticle size of 663 µm nd 654 µm, respectively. 90% of their prticles were below 1237 nd 1210 µm. Both men prticle size nd prticle size distribution of brns C, E nd F were lmost identicl. Although brn G hs the 66

85 sme prticle size cut off (977 µm) s brns E nd F, the men prticle size of the resulting popultion ws found to be 1005 µm, with d90 vlue of 1568 µm. Although brns E nd F were obtined through sifting followed by grinding to pss through 977µm screen, brn G did not require further grinding s the screen size mrches the trget cut off size. This frction corresponds to the fine brn prticles (.k. shorts) obtined by commercil milling, s well s smll portion germ nd floury endosperm prticles s seprted in the usul processes of commercil flour. Chemicl composition: The composition of ll brn frctions vried little (Tble 3.3) s they were obtined by sifting or grinding process from single source of the whet brn. The sifting nd grinding process of brn cused no structurl difference nd only resulted in subdividing the brn with miniml compositionl chnge. Their protein content vried between 16.53% nd 17.06% with no significnt difference (p 0.05) between type of brns Tble 3.3. The compositionl nlysis of brn hs been well estblished in numerous publictions. The brn lyers re chemiclly comprised of rbinoxyln (AX) (38%) > protein (25%) > cellulose (16%) > lignin (6.6%) (Brillouet nd Mercier 1981; Brillouet et l 1982; DuPont nd Selvendrn 1987). Amrein et l (2003) nd Mes nd Delcour (2001) reported the verge brn composition from commercil milling s 41-60% non-strch polyscchrides, 10-20% strch, nd 15-20% protein. Lipid content of Ctegory-I brns (A, B, C nd D) rnged from 0.56 to 0.86, lthough they ll re originted from the sme strting s is brn (Tble 3.3). This could be explined by the dependence of lipid extrction efficiency on prticle size. Luthri et l (2004) reported tht crude ft content in corn vried with chnges in grinding conditions nd tht ws due to the differences in proportion of finer prticles, which incresed the crude ft extrction efficiency. Brn A nd B hve lipid content of 0.56 nd 0.56% (no significnt difference t p<0.05), while brn C nd D hve significntly higher lipid content t %. Further grinding from 1000 µm cut off to 140 µm cut off did not ffect the extrctble lipid content. Brn E nd F hve the highest lipid content t %. Although brn E nd F hve men prticle size comprble to tht of brn C, they hd significnt differences (P 0.05) in their lipid contents. Brns E nd F were obtined through sifting s is brn to form sub-frctions in the rnge of µm nd µm (Tble 3.3). In processing, the multiple lyers comprising brn is usully removed s one component with some (miniml) strchy endosperm ttched. As whole, brn is high in brnched 67

86 heteroxylns, cellulose nd lignin (Fincher et l 1974; Hemery et l 2011), even though compositionl differences mong the lyers is known to exist. Studies hve shown tht breking whet brn lyers into three prts (leurone, intermedite, nd pericrp), results in frctions with different compositions (Brron et l 2007; Jerkovic et l 2010; Nurmi et l 2012). Brn E nd F resemble lrger prticles of the s is brn. Lrger prticle sizes re reported to be obtined from outer brn lyers (Peyron 2002), nd contin more lipid content compred to the smller prticle sizes. Brn G corresponds to predominntly shorts nd residul floury endosperm prticles. It hs 0.79% lipid content, which is unique mong the rest of the brn smples. Crude fiber content rnged from 20.9 to 35.44% (Tble 3.3). Brn A nd B were gin very similr to ech other with crude fiber content of 21.1%. Among the ctegory-i brns, the crude fiber content incresed with decresing prticle size (A=B < C < D). Brn E nd F hve higher fiber content, 32.6 nd 35.4%, respectively. As explined bove, these frctions correspond to lrger prticles of the s is brn, which is mostly composed of pericrp. In whet brn, leurone cells re high in proteins, ferulic cid, nd lipids, nd re composed of thick nonlignified cell wlls (Fulcher nd Duke 2002), wheres the pericrp hs thick, lignified cells (Cheng et l 1987). This lso explins the reltively low crude fiber content (20.9%) of brn G. In generl, the sifted fine prticle sizes hd lower fiber content thn the lrger prticle sizes s expected. Similr results hd been reported by Protonotriou et l (2015). The fiber content incresed when the brn prticle sizes re obtined by milling process. The increse in fiber content ws explined by possible interctions between protein nd hemicellulose or crosslinking/oxidtion mong compounds during milling process (Protonotriou et l 2015; Drkos et l 2011). Lstly, sh content of the brn smples vried between 4.93 nd 7.57% (Tble 3.3). Among the ctegory-i brns, which re expected to hve identicl chemicl composition, the sh content incresed with decresing prticle size (A < B < C < D) indicting tht sh content is influenced by the prticle size. However, there ws no significnt difference (p 0.05) in sh content of the brns except for brn D. Ctegory-II brns, which originted from different subfrctions of the s is brn, hve significntly different sh contents (p 0.05). Despite of the decresing prticle size, the sh content rnked s E > F > G. This could be explined by the origin of these brn smples. Outer brn lyer or pericrp is composed of thick lignified cells tht hve high mount of inorgnic mteril, compred to the inner lyers of brn tht typiclly form 68

87 the shorts. Peyron et l (2002) reported tht brn prticle sizes were obtined from different brn lyers (outer pericrp, nucellr epidermis, test nd inner pericrp) of the whet grins during milling would be relted to the decrese in brn extensibility mesured nd increse in brn fribility. The strin rte pplied on the brn lyers during the milling process could modify the rheologicl behvior of the brn portion, which hs high plsticity. In short, it ws concluded tht, bsed on the similrities in their physicl (prticle size) nd chemicl properties, these seven brn smples cn be regrouped in four: A B, C E F, D nd G which resulted in similr performnces s discussed in future sections Solvent Retention Cpcity (SRC) of the Brn Frctions There re three min functionl polymers in whet: Protein, strch (dmged) nd pentosns (Kweon et l 2011). Ech of these polymers is ble to bsorb prticulr solvent: 5% sodium crbonte for dmged strch, 50% sucrose for pentosns, nd 5% lctic cid for glutenins. The working principle of solvent retention cpcity (SRC) is to mke flour swell into these solvents, then force the solvent out of the polymer. If the polymer hs high functionlity, it retins higher quntity of solvent. The wter-solvent retention cpcity (W-SRC) is relted to the overll wter holding cpcity controlled by the flour functionl components including gluten, dmged strch, nd pentosns nd represent the combined contributions of lctic cid-solvent retention cpcity (LA-SRC), sodium crbonte-solvent retention cpcity (SC-SRC), nd sucrose-solvent retention cpcity (Su-SRC) vlues (Kweon et l 2011; Gines 2000). All the other three retention prmeters re relted to strch nd non-strch polyscchrides components of whet flour which cn be ffected by the process nd the milling prctice. This method hs been selected to obtin n overll picture of the effect of different brn prticle size nd source levels on whet flour qulity concerning its potentil in bredmking performnce. In the study, the originl brn ws collected nd frctionted into different sizes of sme origin (A, B, C, nd D) nd different origins of sme size (E, F, nd G). The solvent retention cpcity test, vlues of these whet brn frctions in comprison to control flour re shown in Figure 3.2. In generl, SRC of brn smples were significntly higher thn tht of bse flour smple. This could be explined by high wter holding cpcity of whet proteins nd fiber. In ctegory-i brns, the W-SRC vlues decresed with the decrese in brn prticle size. All brn 69

88 frctions (A, B, C, nd D) were significntly different (p<0.05). Although brn E nd F hve protein contents similr to tht of brn A nd B, nd hve significntly higher fiber contents thn tht of brn A nd B, their W-SRC vlues were significntly lower. This cn be explined by the differences in the prticle size, which surpsses the compositionl differences. The porous mtrix structure of the insoluble fiber chins cn hold lrge mounts of wter through hydrogen bonds (Kethireddiplli et l 2002). Noort et l (2010) reported tht size reduction of brn from 1,000 to 75 μm, reduced wter holding cpcity from 500 to 250 %. Brn D, E nd F, however, hve similr W-SRC. Brn D ws obtined by sifting process with the smllest prticle size (cut off size < 140 µm, men prticle size of ~110 µm), wheres, brn E nd F were obtined by grinding with similr resulting prticle size (cut off size < 1000 µm, men prticle size of ~660 µm). Despite differences in their ntomicl origins (thus chemicl composition) they displyed comprble hydrtion properties. Brn G, obtined by sifting process, hs higher W-SRC (similr to brn A nd B). The results re in consistent with erlier work of Zhng nd Moore (1997), nd Mongeu nd Brssrd (1982) on whet brn/fiber, nd Ahmed et l (2015) on β- glucn fiber in flour doughs. The uthors reported the wter bsorption index of whet brn/fiber decresed with reduction of its prticle size. Thus brn prticle size nd shpe re importnt fctors, which will ffect the wter bsorption index, cnnot be generlized nd must be ssessed for ech type of fiber (Perry nd Chilton 1973). A lrger prticle brn frction pcks less efficiently by centrifugtion thn the medium nd smller prticle brn. It hs lso been observed tht smller brn prticle smples tend to hve more wter-soluble loss thn do lrge brn smples nd this might contribute to the differences between the wter bsorption indexes of the different prticle size smples. The rest of the SRC vlues (SC-SRC, LA-SRC, Su-SRC) of bse flour, nd ctegory I nd II brns followed the sme trends with respect to different types of brns s the W-SRC profiles explined bove. Since there is insignificnt mount of residul strch in brn smples (except for Brn G) it is difficult to ttribute these high SC-SRC vlues solely to the mount of dmged strch (Figure 3.2) in comprison to tht of bse flour. The sodium crbonte (SC- SRC) vlues of brn frctions incresed with decrese in prticle size. Brn A, B nd C were significntly different; however, there ws no significnt difference in brn C, D, E nd F (Figure 3.2). 70

89 The LA-SRC vlue reflects flour gluten in functionlity (Kweon et l 2011). Since brn proteins re non-gluten, the observed differences between the brn smples re mostly relted to their hydrtion nd swelling behvior in wter rther thn their gluten functionlity. All ctegory-i brns (A, B, C nd D) were observed to be significntly different in their LA-SRC due the differences in their prticle size which ffect the hydrtion rte nd wter holding bility s explined before. However, brn G displyed high LA-SRC despite of its smll prticle size due to significnt differences in its composition in reltion to its ntomicl origin. Lstly, the Su-SRC reflects flour pentosns in functionlity. Pentosns, which re minor component of whet flour, but ply n importnt role in dough rheology. Pentosns re considered s the chrcteristic constituent of brn. They re hydrophilic nd bsorb s much s 10 times their weight in wter (Kulp 1968; Jelc nd Hlynk 1971). The Su-SRC vlues of brn smples were the highest of ll SRC profiles, typiclly 20-70% higher thn the observed W-SRC vlues which cn be ttributed to 16-22% pentosns present in brn (D ppoloni 1976). Despite of the shift in SRC percentges, the trends remined the sme s tht of W-SRC with respect to the brn types Solvent Retention Cpcity (SRC) of the Composite Flours Trget SRC profiles for hrd whet flour with good bredmking qulity hve been reported to be 70% for W-SRC, 110% for Su-SRC, mx 88% for SC-SRC nd 150% for LA- SRC (Kweon et l 2011). The bse flour used in this study prtilly justified these expecttions with W-SRC of 61.3%, Su-SRC of 83.7%, SC-SRC of 75.8% nd LA-SRC of 114.3% (Figure 3.3). SRC of composite flours t 5 nd 10% brn replcement levels ws studied in comprison to the control flour (no brn) s shown in Figure 3.3. Presence of brn resulted in slight increse in ll SRC profiles except for LA-SRC, especilly t 10% replcement level. The effects were not ll sttisticlly significnt (p 0.05). Bse flour hs W-SRC of 61.3% while W- SRC vlues in the presences of brn incresed by %. Ten percent brn replcement resulted in lrger shifts in W-SRC vlues of % compred to % increse t 5% replcement for ll brn types except for brn G. The flours with excessive wter retention require incresed bking nd energy cost in bking industries (Guttieri et l 2001). Thus, the observed chnges in W-SRC up to 4.3% in this study were not concerning. 71

90 Su-SRC of bse flour ws 83.7% while presences of brn resulted in mixed effect (Figure 3.3). At 5% brn replcement level, Su-SRC decresed up to 2.2%, except for brn E. At 10% replcement levels, lmost ll brn smples resulted in increse in Su-SRC vlues by %, were the highest increse ws observed for Brn D. This is the brn smple tht ws ground to pss through the finest screen size (i.e. 140 µm) which possibly exposed more pentosns nd mde them vilble for hydrtion. SC-SRC of bse flour ws 75.8% while the vlues in the presences of brn incresed by up to 4.3%. The highest shift ws observed when brn D ws dded t 10% replcement level. Brn D ws ground ggressively to pss through the finest screen size (i.e. 140 µm) which possibly cused further dmge in residul strch ttched to brn prticles. Similr to W-SRC vlues, The SC-SRC vlues in the presence of brn E nd F were not significntly different (p 0.05), but they were significntly higher s compred to brn G (Figure 3.3). The SC-SRC vlue mesures the contribution of dmged strch in flour to its bking performnce nd well known tht flour with higher SC-SRC vlue poses negtive effect on its bking performnce. The lrgest chnges were observed in LA-SRC vlues. LA-SRC of bse flour ws 114.3%, which decresed significntly (p 0.05) by % t 5% brn replcement, nd further decresed up to % t 10% brn replcement level (Figure 3.3). This indictes tht presence of brn decresed the gluten functionlity s indicted by low LA-SRC vlues becuse of gluten dilution nd interference of brn prticles. The brn prticles interfere with ccurte LA-SRC mesurement due to esy swelling of brn in lctic cid solvent. The LA-SRC vlues were lower for both brn source nd size levels s compred to W-SRC nd SC-SRC vlues, but there ws no significnt difference in regrds to different ctegories of brn (Figure 3.3). Protein content lone is n uninformtive flour specifiction, becuse it includes both (functionl) gluten nd (non-functionl) non-gluten proteins. Even with regrds to gluten, its constituent proteins, glidins nd glutenins, mnifest quite different functionlities (Slde et l 1989): glidins re lower-mw, viscous, extensible, two-dimensionl film formers, not network formers, wheres glutenins re higher-mw, elstic, three-dimensionl network formers (Kweon et l 2011). Although SRC testing hs been used to dte minly for evluting soft whet flour qulity (Kweon et l 2011), it hs been reported to be good predictor for evlution of hrd winter whet qulity for bred mking. Xio et l (2006) showed tht LA-SRC correlted with 72

91 the qulity of gluten protein relting to bked lof volume over wide rnge of flour protein contents. They lso reported tht their LA-SRC results were significntly correlted with SDSsedimenttion volume dt nd tht the SRC test ws relible in predicting the lof volume of breds for hrd winter whet flours with similr protein contents. Colombo et l (2008) reported study on the use of SRC testing for qulity prediction of different Argentinen whet flours used for bred production. Their results showed positive correltion between bred lof volume nd LA-SRC. Duyvejonck et l (2011) reported studies on the reltive contributions of whet flour constituents to SRC profiles for commercil Europen whet flours. They concluded tht SRC vlues re good, time-efficient, nd simple bred qulity predictors for Europen commercil whet flours Dough Development Mixogrph The mixogrph is widely used recording mixer. The quntittive informtion provided by the mixogrph is similr to those defined for the Frinogrph. Pek mixing time is similr to dough development time. Pek height (%) provides informtion bout flour strength nd bsorption. Resistnce to brekdown is similr to MTI. In this study, effects of brn source, prticle size nd substitution levels on mixing properties were studied under 2 conditions; optimum wter bsorption nd constnt wter bsorption. Optimum nd constnt wter bsorption re two different pproches to dough wter content. Optiml dough wter bsorption is criticl in commercil bred production becuse vrition in flour-wter bsorption drmticlly ffects dough hndling nd lof volume. Constnt (nonoptimized) wter bsorption is more common in engineering studies. Viscoelstic properties of the doughs t constnt wter bsorption were evluted s optimum wter bsorptions do not llow the decoupling of the effects of hydrtion nd fiber. These two dough development protocols were used in this study to gin better understnding of effects of brn source nd size on mixing properties nd rheologicl properties. Constnt wter bsorption: The Frinogrph wter bsorption of strong (S) flour nd wek (W) flours ws found to be 58.70% nd 56.75%, respectively. These vlues were kept constnt to study the Mixogrph properties of for ll brn substituted S nd W flour doughs t constnt WA protocol. To elucidte the effect of brn substitution, mixogrph pek mixing time 73

92 nd pek height for strong nd wek flour doughs were mesured (Figure 3.4, c). Presence of brn resulted in n increse in the pek time of S flour doughs independent of the brn type. Although the increse ws not sttisticlly significnt t 5% replcement, brn A, B nd G t 10% replcement resulted in significntly higher pek times in comprison to the control S flour dough smple (Figure 3.4). However, W flour dough pek time remined firly constnt t both 5% nd 10% replcement level for ll brn smples (Figure 3.4c). Anlysis of vrince (ANOVA) results (Tble 3.8b) indicted tht there ws no significnt difference in pek time of brn substituted wek (W) flour doughs with regrds to brn prticle size nd source (p 0.05) nd replcement level (p 0.05) compred to control flour doughs. However, pek time of brn substituted S flour doughs ws significntly (p 0.05) ffected both by brn source nd replcement level (Tble 3.8b). In generl, pek height of S flour doughs ws negtively influenced by the presence of brn independent from brn type nd replcement level (Figure 3.4b). All S composite flour dough smples, except for brn D contined smples, exhibited significnt decrese in their pek height compred to the control smple. Decrese in pek height ws more pronounced t 10% brn replcement for ctegory-i brns. The pek height of Ctegory-II brn contining S flour doughs were not influenced by the replcement level. The pek height of W flour control dough ws significntly lower thn tht of the S flour dough, s expected. Most of the W composite flour doughs hd slightly higher pek height in comprison to W flour dough. This increse ws significnt (p<0.05) in brn D both t 5% nd 10% replcement, for brn F nd G t 10% replcement (Figure 3.4d). ANOVA results indicted tht both brn type nd replcement levels hd significnt effect (p 0.05) on both S nd W flour doughs (Tble 3.8b). Optimum wter bsorption: Figure 3.5 presents the pek mixing time nd pek height mesured for brn contining S nd W flour doughs nd control doughs (no brn) t optimum wter bsorptions. In generl, the trends explined bove with respect to brn type nd replcement level were remined the sme, lthough the pek mixing time vlues of optimum WA were higher thn tht of constnt WA protocol. This implies tht t constnt wter bsorption brn nd flour re competing for wter nd developing firly quickly. Doughs developed through optimum WA protocol hd enough wter both for brn nd flour, however it took slightly longer time possibly due the hydrtion behvior of the brn. In generl, the pek time of S flour doughs incresed in the presence of brn. The effect ws significnt (p 0.05) t 74

93 10% replcement for entire ctegory-i nd II brns (Figure 3.5). There ws no significnt difference (p 0.05) in pek mixing time of W composite flour doughs (Figure 3.5b). The bndwidth of the mixogrph curves ws wider for doughs mde of strong protein qulity flours thn the doughs of wek protein qulity flours (dt not shown). The incresed replcement levels of both ctegory-i nd II brns decresed the pek height (%) of S flour doughs which represents decrese in flour strength nd bsorption. Decrese ws more pronounced in ctegory-i brns, especilly brn A nd B t level up to 5% reduction in pek height. S flour doughs contining brn E nd F of ctegory-ii brns hd reltively higher pek heights indicting the lest detrimentl effect of these brns compred to the rest of the brns. Pek height of W flour dough ws lower thn tht of S flour dough s explined before. The inclusion of ctegory-i or II brns did not cuse further decrese in the dough strength. Especilly pek height of ctegory-ii brn including W flour doughs were comprble to tht of the control smple. ANOVA results t optimum WA (Tble 3.8c) were similr to tht were presented for the constnt WA protocol. Both brn type nd replcement levels hd significnt effect (p 0.05) on pek height of both S nd W flour doughs. Pek time ws significnt only for the S flour doughs Frinogrph Doughs were prepred from S nd W bse flours lone nd in the presence of ctegory-i nd II brns t 5 nd 10% replcement levels. Figure 3.6 presents the wter bsorption (WA), dough development time (DDT) nd stbility dt mesured for the brn dough formultions. The wter bsorptions of S nd W flour doughs were 58.70% nd 56.75%, respectively. These vlues re in ccordnce with the published dt. Stojcesk nd Butler (2008) evluted the wter bsorption of the flours of twenty-four whet vrieties nd found vlues between 58.8% nd 60.6% with vrying protein content. Inclusion of brn resulted in significnt increse in the WA vlues irrespective of brn type. The WA of S flour doughs incresed significntly from 58.7% to % in the presence of brn. Fiber substituted flour doughs re known for their bility to bsorb significnt mounts of wter (Cmpbell et l 2008; Linlud et l 2009). The presence of lrge numbers of hydrophilic groups which llows more wter interctions through hydrogen bonding plys mjor role here (Rosell et l 2001). Wter bsorption is minly ffected by source, structure, isoltion method, 75

94 porosity nd prticle size. Reserch on whet cultivrs reported tht brn with different chemicl compositions cn led to different hydrtion cpcities, nd tht these differences product qulity (de Kock et l 1999). No significnt differences were seen for brn tht ws obtined by sifting nd grinding process. Incresed sucrose nd sodium crbonte SRC vlues indicted increses in strch dmge nd pentosn content. In our study, there ws n incrementl increse in WA when the brn replcement ws incresed from 5 to 10% both for S nd W flour doughs (Figure 3.6, b). The brn prticle size hd high impct on both S nd W flour compred to brn ntomicl origin. The lower the prticle size the higher the WA of ctegory-i brn contining flour doughs. This is in contrdictory to the hydrtion behvior of brn smples. As presented erlier, there ws n inverse reltionship between the prticle size nd W-SRC of ctegory-i brns (Figure 3.2). W- SRC of composite flour smples, however, remined constnt t for ll brn types nd both replcements levels of 5 nd 10% (Figure 3.3). WA required to rech 500 FU consistency, s n indiction of optimum mixing nd dough development, displyed n opposite trend. There is grdul increse in WA vlues s the brn prticle size decresed from 3000 µm (brn A) to 140µm (Brn D). The wter bsorption of both flour doughs ws the highest with n verge of 63.5% in the 10% brn D replcement. Dough development time (DDT) of brn supplemented S nd W flours incresed significntly for ll brn prticle sizes nd sources. Similr increse in DDT with the ddition of vrious brn sources (whet, rice, rye) hs been reported (Sudh et l 2007). In W flour doughs, except for brns C, D, E nd F t 5% replcement, ll brn smples t ll replcement levels resulted in significnt increse in DDT (Figure 3.6d). Dough stbility n importnt qulity fctor in dough development nd mchinbility. Presence of brn, independent of type nd replcement level, cused slight decrese in recorded vlues however it did not ffect the stbility of S flour dough significntly (p 0.05) with the exception of A nd B brn t 10 % replcement. W flour doughs, however, benefited from the inclusion of brn s the stbility vlues incresed from 8 min to up to round 12 min, which were comprble to tht of S composite flour doughs (Figure 3.6f) except for brn A t 10% replcement. Ahmed et l (2013) nd Mis et l (2012) reported similr observtions for dte fiber nd crob fiber, respectively. 76

95 Anlysis of vrince (ANOVA) test results (Tble 3.8d) indicted tht both brn type nd replcement level were significnt for ll three prmeters (WA, DDT nd stbility) for both flour types t p Dough Rheology Multiple studies hve evluted the viscoelstic properties of whet flour dough with the im of studying the influence of flour qulity, dough ingredients, nd processing conditions on fundmentl rheologicl properties (Amemiy nd Menjivr 1992; Nvickis et l 1982). The vilbility of incresingly rheometers creted gret del of interest in chrcterizing whet flour doughs nd glutens of vrying qulity by fundmentl rheologicl tests (Sfri-Ardi nd Phn- Thien 1998; Wikström nd Elisson 1998). Fundmentl rheologicl testing such s dynmic oscilltory mesurements or creep recovery, is often used for dough chrcteriztion nd to gin informtion on the structure of the composite mterils. Elucidting the effects of whet brn of vrying ntomicl origin nd prticle size on the rheologicl properties of whet flour doughs with different bredmking qulity would be helpful in determining both dough hndling properties during processing nd the qulity of the end products. The next sections explore nd compre the behvior of two ctegories of brn smples in two different whet flour doughs (strong nd wek) t two brn replcement levels (5 nd 10%) by dynmic oscilltory mesurements in the liner viscoelstic region, nd creep recovery nd unixil extensionl testing t under high sher stress Smll Deformtion Behvior Stress Sweeps (Liner Viscoelstic Region) Stress sweeps t constnt frequency of 1 Hz were performed to determine the dough s liner viscoelstic region (LVR) using stress-controlled rheometer. The mechnicl spectr (dt not shown) of storge (G ) nd loss (Gʺ) moduli were constnt for stress vlues up to 30 P wheres moduli strted to decrese t higher vlues, indicting the onset of non-liner behvior. Thus, 30 P ws used in subsequent experiments. In strin-controlled rheometers, however, the elstic modulus (G ) hs been reported to strt decying bove 0.1% strin nd disply lrge drop bove 1% strin, indicting the 77

96 brekdown of the dough structure beyond this deformtion level (Phn-Thien nd Sfri-Ardi 1998; Weipert 1990) Frequency Sweeps Frequency sweeps involved incresing the frequency of oscilltion from 0.1 Hz to 100 Hz while keeping stress constnt t 30 P. Mechnicl spectr provided set of rheologicl prmeters from ech test, nmely storge modulus (G ), loss modulus (G ), complex modulus (G*), tngent delt (tn δ, G /G ), nd complex viscosity (η*) in the liner viscoelstic rnge (Figure 3.7 through Figure 3.16). Mechnicl spectr for the bse flours (S nd W) reveled tht G > G over ll frequencies indicting the viscoelstic nture of wht flour dough, s expected. Phse ngles tht were below 45º (i.e. tn delt < 1.0) displyed slightly more solid-like mteril property of doughs. Both G nd G were higher for W control flour dough thn for the S control flour doughs, indicting the formtion of much stiffer dough in the cse of the poor bredmking qulity flour. Lower vlues of storge nd loss moduli (G nd G ) for S flour dough over the entire frequency rnge fit with observtions by other uthors tht higher dough strengths correlte with lower moduli vlues t smll deformtions (Sfri-Ardi nd Phn-Thien 1998; Uthykumrn et l 2002). Similrly, Khtkr nd Schofield (2002) nd Petrofsky nd Hoseney (1995) observed tht doughs from poor bredmking whets hd G vlues of greter mgnitude thn those of the good bredmking whet cultivrs. The frequency scns showed tht both S nd W flour dough smples displyed higher vlues of G nd G t higher frequencies compred with low frequencies. These results indicte tht the recovery of the stressed dough network ws slow process; tht is, the network ws not completely elstic. Dreese et l (1988) reported similr trend tht G, G, nd tn delt of flour dough were frequency dependent nd incresed with incresing frequency. This behvior implies tht the dough cts more like solid, when subjected to slow rtes of deformtion, nd this strts to reverse when it is deformed rpidly. A similr frequency dependence ws noted by Bltsvis et l (1997) nd Pedersen et l (2004) for cookie doughs. Frequency sweep experiments were first conducted using constnt wter bsorption protocol to single out the effect of brn inclusion on rheologicl properties (Figure 3.7, 3.11, 3.13, 3.15). Wter bsorption level plys vitl role in rheologicl properties of the dough, on 78

97 dough hndling nd product qulity. In dough, wter intercts with gluten nd strch to form the continuous gluten phse. The distribution of wter vries mong the flour constituents nd strongly influenced by mount of protein, dmged strch nd other components such s brn, which hs high wter holding cpcity (Bushuk 1966). In generl, S nd W composite flour dough smples showed response typicl of crosslinked polymer network with predominnt solid-like behvior (G > G ). This is true representtion of viscoelstic network. Such behvior ws erlier reported by vrious reserchers for fiber-enriched dough (Mis 2011; Singh et l 2012). Both control nd composite dough smples t 5 or 10% brn replcement showed n increse in G nd G with incresing frequency from 0.1 to 10 Hz, with the elstic behvior dominting over viscous component throughout the frequency rnge. Brn enriched dough showed higher mechnicl strength thn the control smples indicting much stiffer dough. An increse in rheologicl moduli with fiber incorportion hs been reported in the literture (Ahmed t el 2013). The higher G for brn enriched flour doughs could be ttributed to the limited plsticiztion effect leding to incresed dough mechnicl property. Storge nd loss moduli of S composite flour doughs contining ctegory-i brns displyed significnt difference (p 0.05) with respect to replcement level. Both G nd G incresed further t 10% replcement compred to 5% replcement. However, W composite flour dough smples did not hve ny distinction with respect to the brn replcement level. Although inclusion of ctegory-i brns shifted the moduli to higher vlues, 10% replcement level did not cuse further increse in moduli. There ws no distinction between the 5% nd 10% replcement levels when ctegory-ii brns were included in both S nd W flour doughs (Figure 3.7 nd Figure 3.9).When the frequency sweep test ws repeted for the dough smples prepred under optimum wter bsorption protocol (Figure 3.8 nd Figure 3.10) the trends explined bove did not chnge. However, the mgnitude of shift in the moduli of S nd W flour doughs in the presence of brns ws much less significnt. The excess wter provided during dough development, following the optimum wter bsorption protocol, minimized the competition between flour (especilly protein in flour) nd brn nd thus llowed gluten to develop fully nd form continuous network without creting stiff dough. Since the mechnicl spectr provide continuous dt set, it is often difficult to mke comprisons between two different experimentl dt sets in quntittive mnner. To overcome this, it is common prctice to report G nd G t 1 Hz constnt frequency. Figure 3.11nd 79

98 Figure 3.12 provide such informtion for dough smples prepred t constnt WA nd optimum WA, respectively. G t 1 Hz of S composite flour doughs incresed by 40-90% t 5% brn replcement level, while the chnge ws s high s % when brn ws dded t 10% replcement. Although similr trends were observed for W flour dough, the chnge in G t 1 Hz ws 8-25% t 5% brn replcement, nd 25-80% t 10% replcement. The G vlues of composite flour doughs experienced much higher increse in comprison to control doughs: up to 250% in S composite flour dough nd 180% in W composite flour dough (Figure 3.11). Dough smples prepred under optimum WA protocol displyed similr trends with less pronounced effects. As explined erlier, excess wter provided to stisfy optimum dough development minimized the competition between flour nd creted less stiff doughs (Figure 3.12). The differences in protein content nd prticle size distribution cn explin the higher moduli of brn substituted flour doughs versus the control flour dough. The overll protein content in brn flour dough is higher thn the control flour dough, which mens smller mount of strch present in brn substituted flour doughs. This cn be explined s whet flour protein contins glidins nd glutenins tht provides viscoelsticity nd strength re diluted when brn frctions re substituted in flour doughs. Thus, the brn substituted strong or wek flour doughs give higher moduli thn flour doughs with no brn. The decrese in glutenin nd glidin rtio lso ffects the lrge deformtion rheologicl properties such s extensibility of the doughs s it will be discussed in lter sections of this chpter. The observtions lso support the previous studies done on flour reconstitution experiments nd correltion studies hve shown tht the bking qulity of vrious flours nd rheologicl properties re primrily relted to the gluten protein frction of the flours (McRitchie 1992; Mgnus et l 2000). The increse of storge nd loss moduli with other dietry fiber dditions hs lso been reported (Izydorczyk et l 2001; Sntos et l 2005; Peressini, nd Sensidoni 2009; Bonnnd-Ducsse et l 2010). The viscoelstic nture of the dough cn be further described by clculted slopes of the liner regression of the power-type reltionship of ln G versus ln frequency ( which is commonly used to predict the solid-like chrcteristics of polymers. The frequency dependency of biopolymers is reported to hve three zones: the rubbery zone, the entngled zone, nd the free-flow (or rection) zone. The frequency dependency of G, G, nd tn δ cn be monitored to identify phse behvior of proteins, whether it is in the rubbery zone, entngled polymer flow 80

99 region or the rection zone (Dogn nd Kokini 2007). The slope of logrithmic plots of G versus frequency ( ) bove 0.3 is high enough to suggest tht the mteril hd non-network structure cpble of experiencing entngled polymer flow. A true gel is chrcterized by zero slope of the power lw model (Ross-Murphy 1984). Incorportion of brn into whet flour dough significntly ffected the rheologicl properties. The slopes presented in Tble 3.4 nd Tble 3.5 rnged from to indicting good network development. The slope of curves of composite dough decresed significntly with the increse in the percentge brn dditions in whet flour dough. Typiclly, brn replcement t 5% resulted in lower slope vlues compred to control doughs, nd 10% brn replcement led to further reduction, which ws sttisticlly significnt for most brn smples. Slopes round 0.2 or lower hve been reported to suggest shorter-rnge networking compred to entngled polymer flow zone (Dogn nd Kokini 2007). When the slope gets closer to zero, reching plteu, it indictes cross-linked network. Brn D (the smllest prticle size) nd brn G (the fine brn frction obtin through sifting) dded to strong flour t 10% replcement level resulted in the most drmtic chnge in slope vlues, from control vlue of to nd 0.109, respectively. When dded to W flour sme ctegory-i nd II brns cused lesser degree of chnge in slope since the bse vlue for W flour control dough ws inherently much below thn tht of the S flour dough. Optimum wter bsorption protocol resulted in smller mrgin of chnge in slope vlues (from to in S flour composite doughs) due to lck of competition for wter between brn nd flour. Under optimized conditions whet proteins hve better chnce of hydrting nd forming well-developed network. Anlysis of vrince (ANOVA) results (Tble 3.8e) indicted tht there ws significnt difference (p 0.05) in G t 1 Hz nd G slope brn substituted S flour doughs with regrds to both brn source nd replcement level. However, in W composite flours doughs only replcement level hd significnt effect on these two prmeters. At optimum wter bsorption, incresing frequency from 0.1 to 10 Hz incresed both storge (G ) nd loss (G ) moduli (Figure 3.7 through Figure 3.10), with the elstic behvior dominting over the viscous component throughout the entire frequency rnge exmined. At low frequencies, the tn delt (G /G ) ws round 0.5 wheres t high frequencies, the tn delt incresed bove 1.0 (Figure 3.13 nd Figure 3.14). Lower vlues for phse ngles re indictive 81

100 of more elstic nture. This implies tht control (S nd W) flour doughs hve the higher elstic nture t smll deformtions cross rnge of frequencies. The results showed tht ll brn substituted flour doughs incresed their phse ngles with incresing frequency, nd higher phse ngle indicte tht lrger frequencies cuses the viscous nture of the smples to increse. The increse in viscous nture of the dough cn be explined since phse ngle is the rtio of G" to G, n increse in the phse ngle reflects tht G" hs greter slope thn G, nd is therefore incresing t fster rte. The complex viscosity ( *) versus frequency plots re given in Figure 3.15 nd Figure In generl, dt indicted stedy decrese in * with incresing frequency for ll brnsubstituted S nd W flour doughs irrespective of brn type nd replcement level, which indictes sher thinning behvior. The dough viscosity incresed with the ddition of brn while the most significnt chnge ws observed in S composite flour dough contining ctegory- I brns where the replcement level ws observed to be criticl. However, in dough smples contining ctegory-ii brns replcement level did not hve further effect on viscosity s both 5% nd 10% dt points overlpped in the sme rnge. Viscosity of W composite flours were minimlly ffected by inclusion of brn smples, especilly the ctegory-ii brns (Figure 3.15). In the dough smples prepred through optimum wter bsorption protocol (Figure 3.16) the forementioned effects were much less pronounced Temperture Sweeps Dough is combintion of strch nd protein in queous medium. Upon het tretment, strch geltinizes nd protein dentures in the dough, thus mking the process is complex one. Nevertheless, the rheologicl properties of whet gluten do not chnge during heting, nd the rheologicl properties of whet dough re predominntly ffected by strch geltiniztion during therml tretment (Dreese et l 1988; Ahmed et l 2013). The conditions pplied in the rheometer did not simulte those previling in rel bking process (Sikor et l 2010), however, the rheometric studies re very useful in exmining strch geltiniztion in the dough. Furthermore, it is believed tht the temperture rnge of C is the controlling fctor for the finl qulity of bred. Initilly, there ws slight decrese in G nd G" until round C, s hs been generlly observed for ll control flour nd whet brn substituted flour doughs (Figure 3.17 nd 82

101 Figure 3.18). This might be ttributed to the swelling of strch during initil stges of heting. Strch grnules strt to swell, leding to n increse of their volume nd becoming closely pcked in the system (Elisson 1986). The decrese in moduli indictes softening of the dough until the geltiniztion temperture is reched round 65 C. The decrese is likely due to α- mylse cting on strch nd relesing some bsorbed wter thereby reducing dough interctions (Slvdor et l 2006). Similr results were observed from previous workers (Lmbert nd Kokini 2001; Angioloni nd Ros 2005). The effect of brn ws observed only in the initil stges of heting before onset of geltiniztion. As the heting temperture ws rised to bove the threshold vlue of 50 C, the G nd G" incresed mrkedly up to 70 C, nd then followed by drop in their mgnitudes. There ws no significnt difference (p 0.05) in G nd G" with respect to brn prticle size or source substitution levels to both strong nd wek flour doughs. Storge nd loss moduli within the brn prticle size (A, B, C, nd D) levels, did not show ny significnce between 5 nd 10% brn substitution for both S nd W flour doughs. However, 10 % brn substituted S flour doughs hve higher G nd G vlues s compred to S control flour dough. A similr trend ws observed for 20% β-glucn fiber substitutions in the dough by et l (2014, 2015). Ble nd Muller (1970) reported tht the loss modulus (G ) decresed initilly while heting the dough to C, nd storge modulus decresed or remined constnt (Legrys et l 1981; Ble nd Muller 1970). Increse in storge modulus (G ) ws ttributed to cross-linking interctions induced in gluten during the formtion of network structure (Kim nd Cornillon, 2001). Protein-protein interctions provided highly cross-linked structure resulting in higher G nd generlly lower G vlues. Dreese et l (1988) explined tht strch geltiniztion, gluten cross-linking, or both would be the ttribute for the thermlly induced rheologicl chnges during bking. Gélins nd Mckinnon (2004) reported tht the effect of temperture on dough rheologicl properties is minly due to the effect of temperture on gluten rheologicl properties s resistnce to mixing increses in heted gluten. He nd Hoseney (1991) suggested tht higher moduli nd loss tngent vlue of the doughs from poor qulity flours resulted either from fewer entnglements or from entnglements tht were esily dissocited. The other reserch reported tht the good bredmking qulity flours hve lower G nd tn delt vlues. The increse in G could be relted to the protein composition of brn flour doughs. Elisson (1983) showed tht high protein content increses the 83

102 strch geltiniztion temperture becuse proteins soluble in wter more esily interct with strch grnule surfce to slow strch swelling nd shifts the geltiniztion temperture. In limited wter systems such s bred dough systems, strch geltinizes cn be ffected by slight chnge in wter vilbility, the presence of lrger mount of proteins interct with wter would likely shift the geltiniztion temperture. The temperture corresponding to mximum vlue of G during heting rmp (denoted s TG mx) cn be considered s pek geltiniztion temperture. The TG mx for S nd W control flour doughs were recorded s 69.3 C nd 70.7 C, respectively. The TG mx of composite flours in the presence of ctegory-i nd II brns were not influenced significntly by the brn content, nd rnged between 68.2 nd 71.8 C for S composite flours (Tble 3.6). Anlysis of vrince (ANOVA) results (Tble 3.8g) indicted tht brn type hd significnt effect (p 0.05) on TG mx of S flour dough, while no significnce ws observed for pek G, pek G nd pek *. For W flour dough, both brn type nd replcement level were observed to hve significnt effect (p 0.05) on TG mx, while other three prmeters hd no significnce. Figure 3.19 indictes tht compred to their control flour doughs, tn delt vlues of composite flours were slightly lower for S flour doughs, while they were slightly higher for W flours dough independent from the brn type. It cn be concluded tht brn imprts strengthening effect in the W flour doughs while it wekens the S flour doughs. Ozboy nd Koksel (1997) showed tht by using empiricl methods, corse brn of some vrieties hs n unexpected strengthening effect on rheologicl properties but hs somewht reduced dverse effect on bking properties. In both S nd W flour doughs, tn delt remined constnt round 0.5 during the initil heting step until the temperture reched round 50 C. There ws drmtic drop to vlues round 0.4 to 0.3 in temperture rnge from 50 to 70 C, while tn delt remined constnt round 0.3 from thereon until the end of the heting period Lrge Deformtion Behvior Creep nd Recovery A typicl chrcteristic of viscoelstic mterils is tht they undergo creep, i.e. they continue to deform under constnt stress or lod. Since the behvior of dough is non-liner, mesurements t high rte of deformtion do not simulte the resistnce of dough ginst slow 84

103 deformtions, such s those occurring in bred mking. However, such type of mesurements cn provide informtion bout the pressure developing in the gs cells nd the resultnt stresses. The creep-recovery curves of doughs exhibit typicl viscoelstic behvior (Figure 3.21), combining both viscous-fluid nd elstic components (Steffe 1992). Creep nd recovery responses of S nd W control doughs re similr to respective curves obtined for whet doughs in previous studies (Edwrds et l 1999; Lzridou et l 2007; Sivrmkrishnn et l 2004). Wng nd Sun (2002) defined tht mximum creep strin could be used to describe dough rigidity (firmness). They lso climed tht stronger doughs with greter resistnce to deformtion hd smller creep strin thn softer doughs. In ccordnce with this view, S flour dough exhibited greter resistnce, showing smller creep strin thn its counterprt W flour dough (Figure 3.21). Furthermore, the dough of the stronger flour exhibited greter strin recovery fter removl of the lod thn its poor qulity flour counterprt. Three importnt creep complince prmeters were obtined from the creep-recovery test: Jmx, the mximum complince, Je, the elstic complince, nd Je/Jmx rtio, the elstic prt of the mximum creep complince. The Jmx vlues of S composite flour doughs were lower thn tht of control dough (Figure 3.21, b) except for brn C t 5% replcement level. Jmx of s flour dough dropped from P -1 to s low s P -1 when brn D ws dded t 10%. Upon removl of pplied stress, the percent recovery in S composite flour doughs s mesured by the Je/Jmx rtio rnged from 51.5% to 59.4 %, control flour being t 56.0%. The Jmx vlue of W control flour doughs ws P -1, while tht of W composite flours rnged between P -1 nd P -1 (Tble 3.7). Upon removl of pplied stress, the percent recovery in W composite flour doughs s mesured by the Je/Jmx rtio rnged from 55.6% to 62.4 %, W control flour being t 60.5%. Ahmed et l (2015) studied the creep nd reltion behvior of β-glucn doughs with respective to prticle size nd found tht creep curves of doughs contining fine prticle size were close to the control dough. This might be explined s the finest prticles produced softer dough with mximum strin vlues nd believed tht lower vlues of wter bsorption by finest prticles re responsible for the dough softness. Tronsmo et l (2003 nd 2003b) indicted tht lrge strin mesurements of creep recovery hve given correltions with lrge moleculr weight glutenin. This indictes tht the creep recovery mesurements re lso relted to protein 85

104 composition. The protein-protein interctions ply significnt role on the rheologicl properties of whet flour doughs. The creep recovery results cn be ssocited with lrge deformtion extensibility test nd bred volume (Sfri-Ardi nd Phn-Thien 1998; Wikstrom nd Elisson 1998), nd strength of durum whet vrieties (Edwrds et l 1999, 2001). This probbly indictes tht the recovery strin represents elstic properties of doughs. Schofield nd Scott Blir (1932) reported tht the proper bred dough must not only be viscous or plstic, but lso be elstic nd recoverble. The creep recovery test provides the mesurement of dough elsticity simply by recovery strin. This test cn be used to clssify nd predict flour qulity for bredmking. Creep recovery tests my give more insight into the mcro-structure of the dough. The recovery is n importnt fctor for dough film stbility. The higher the recovery strin, the better the stbility ginst rupture of dough films between gs cells (Bloksm nd Bushuk 1988). This implies tht brn substituted flour doughs irrespective of brn prticle size nd brn source hs lesser recovery strin nd less stbility compred to strong flour doughs Unixil Extensionl Properties The extensibility tests re typiclly conducted on doughs to evlute their tensile strength nd extensibility chrcteristics bsed on the whet s protein nd gluten qulity. In this study, the extensibility tests were conducted first t the constnt wter bsorption level to single out the brn effect from hydrtion effect. Figure 3.22 represents the effect of brn type nd replcement level extensionl properties of S nd W flour doughs t constnt wter bsorption. There ws no significnt difference (p 0.05) in Rmx of S composite flours irrespective of brn type except brn B t 5%, brn C nd D t 10 % replcements levels. The Rmx of these smples were higher thn tht of the control flour dough. In generl, extensibility of S composite doughs decresed with the ddition of brn, especilly t 10% replcement level. Brn C, D nd E imprted slightly higher E vlues in comprison to the control dough lthough the difference ws not sttisticlly significnt. Strong flour doughs with higher protein content represented higher strength (Rmx) thn wek flour doughs. The observtions re in greement with results reported previously on whet brn ddition of herth bred (Amodt et l 2004) nd ot nd brn fibers on whet bred doughs (Rieder et l 2012). Amodt et l (2004) suggested tht flours contining higher proportions of 86

105 lrge glutenin polymers require time to rech pproprite level of polymer size s prt of developing gluten network is likely to be longer thn for flours with less of the lrgest glutenin polymers. This might explin the longer mixer time requirement found for the strong flour doughs vs. wek flour doughs in the present study. W control flour dough hs lower Rmx compred to S flour dough, s expected. W flour dough did benefit from inclusion of brn s the Rmx vlues went higher in W composite flour doughs. All types of brn t ll replcements levels were significntly higher in Rmx, except for brn E t 5% replcement. However, the extensibility of W composite doughs decresed significntly with the ddition of brn, especilly t 10% replcement level, with the exception of brn C, E, nd F t 5%. The composite dough smples prepred t optimum wter bsorption exhibited much less drmtic differences in their Rmx compred to their control flour counterprts (Figure 3.23). However, brn replcement hd strong effect on the extensibility dt t optimum wter bsorption, s it ws the cse in constnt wter bsorption. Dough hndling in commercil production lines includes mixing, molding, nd resting (Weipert 1991). Extended dough resting time might help the brn substituted flour doughs to reggregte the gluten protein polymers nd no significnt difference ws observed when compred to control flour doughs for both strong nd wek protein qulities. Extensibility hs ffected with brn substitution in strong nd wek flour doughs. There ws lrger difference in 10% brn substitutions in the flour. The higher percent of brn ddition into the flour dilutes the protein qulity nd ffects the viscoelstic properties of the dough. In ddition, wter bsorption level in the dough lso influences the rheologicl properties including tensile strength (Muller nd Hlynk 1964) nd the results re meningful only t specified level. Amodt et l (2004) studies showed tht wek protein qulity flours were more extensible thn the doughs mde from strong protein qulity. The ddition of brn to whet flour doughs dilutes the concentrtion of gluten-forming proteins, nd the brn prticles disrupt the gluten network (Gn et l 1992). The dilution effect nd the disruption of gluten network might contribute to decresed extensibility of the dough in the present study. The substitution of brn ppers to hinder the gluten network formtion nd results in decresed extensibility Stress Relxtion 87

106 Stress relxtion test is used to determine the time dependence of the viscoelstic properties of doughs. The stress relxtion curves re plotted s G(t)/G0 versus time, where G(t) is the relxtion modulus t ny time nd G0 is the initil modulus. Stress relxtion depends on the moleculr weight of proteins; higher the moleculr weight, longer time to relx thn with fewer high moleculr weight proteins. Lrger proteins needed more time to rerrnge into low energy conformtions thn smll proteins. Stress relxtion dt of whet flour dough usully gives the bimodl behvior in the relxtion spectr. Ro et l (2000) ttributed the bimodl distribution of relxtions times to blend of low nd high moleculr weight polymers. They suggested tht the first pek represents entnglements between low moleculr weight proteins, possibly with some high moleculr weight proteins. The second relxtion pek is relted to the entnglements properties of moleculr weight insoluble glutenin polymers. This hs been shown to be directly relted to insoluble frction of the high MW glutenins. Stress relxtion test ws performed both for strong whet flour lone nd t 5 nd 10% replcement levels for ll seven brn smples. However, no dt ws not included to this thesis due to the nomlies in the test outcomes Conclusions The study gve n overview of the reltionships between vribles obtined from rnge of different mesurements of brn substituted flour dough with respect to brn prticle size nd source. Frinogrph dt demonstrte slight difference between ll brn flour doughs; it hs been shown tht totl brn increses the wter bsorption nd the dough development time. The physicl properties of the brn flour doughs were directly compred using unixil extension by the Kieffer rig test. The brn contining doughs were more dependent on the protein content. There is no difference between the ctegory-i nd ctegory-ii brn inclusions in the performnce of strong flour doughs. The brn substitution in wek flour doughs cuses strengthening effect nd while it wekened the strong flour doughs Acknowledgements This study ws supported by the USDA-NRI grnt. The uthors would like to pprecite the help of Quinten Allen, Shwn Thiele to use the whet brn obtined during milling process t Hl Ross Flour Mill of the Dept. of Grin Science nd Industry t Knss Stte University. The 88

107 uthors would like to thnks Dr. Jyendr Ammchrl nd his students of the Dept. of Animl Sciences nd Industry t Knss Stte University for llowing the use of Rheometer, Dr. Jeff Wilson, Hien Vu of USDA-ARS for helping in use the Prticle Size Anlyzer. 89

108 3.6. References AACC, Americn Assocition of Cerel Chemists Approved Methods, 10th ed. The Assocition, St Pul, Minnesot. Amodt, A., Mgnus, E. M., Feergestd, E. M. (2003). Effect of flour qulity, scorbic cid, nd DATEM on dough rheologicl prmeters nd herth loves chrcteristics. Journl of Food Science, 68: Amodt, A., Mgnus, E. M., Feergestd, E. M. (2004). Effect of protein qulity, protein content, Brn ddition, DATEM, proving time, nd their interction on herth bred. Cerel Chemistry, 81(6): Ahmed J. (2014). Effect of prticle size nd temperture on rheology nd creep behvior of brley β-d-glucn concentrte dough. Crbohydrte Polymers, 111: Ahmed, J., Almusllm, A. S., Al-Slmn, F., AbdulRhmn, M. H., Al-Slem, E. (2013). Rheologicl properties of wter insoluble dte fiber incorported whet flour dough. LWT-Food Science nd Technology, 51: Ahmed, J., Almusllm, A., Al-Hooti, S. N. (2013). Isoltion nd chrcteriztion of insoluble dte (Phoenix dctylifer L.) fibers. LWT-Food Science nd Technology, 50: Ahmed, J., Thoms, L., Al-Attr, H. (2015). Oscilltory rheology nd creep behvior of brley β- D-glucn concentrte dough: Effect of prticle size, temperture nd wter content. Journl of Food Science, 80 (1): E Amemiy, J. I., Menjivr, J. A. (1992). Comprison of smll nd lrge deformtion mesurements to chrcterize the rheology of whet flour doughs. Journl of Food Engineering, 16: Amirkveei, SH., Shhedi, M., Kbir, GH., Kdivr, M. (2009). Effects of treted nd untreted brn in dough dynmic rheology. Interntionl Journl of Food Sciences nd Nutrition, 60 (S1): Amrein, T. M., Gränicher, P., Arrigoni, E., Amdò, R. (2003). In vitro digestibility nd colonic fermentbility of leurone isolted from whet brn. LWT-Food Science nd Technology, 36: Anderson, R. A., Conwy, H. F., Pfeifer, V. F., Griffin, E. L. (1969). Geltiniztion of corn grits by roll nd extrusion cooking. Cerel Science Tody, 14:4-12. Angioloni, A., Dll Ros, M. (2005). Dough thermo-mechnicl properties: Influence of sodium chloride, mixing time nd equipment. Journl of Cerel Science, 41: Angioloni, A., Collr, C. (2009). Bred crumb qulity ssessment: plurl physicl pproch. Europen Food Reserch nd Technology, 229:

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118 Tble 3.1 Properties of flour smples Composition Strong (S) flour Wek (W) flour Protein content (%) Moisture content (%) Frinogrph properties Wter bsorption (FU) Development time (min) Stbility (min) Degree of softening (FU) Mixogrph properties Wter bsorption (%) Pek time (min) Pek height (%) Dt re men of duplictes ± stndrd devition. *Protein= n x 5.27 fctor 100

119 Tble 3.2 Clssifiction of the brn smples Ctegories Originl prticle size rnge Ctegory-I < 2920 µm Ctegory-II µm Ground nd pssed through Designtion nd prticle size cut off 2920 µm screen A < 3000 µm 2030 µm screen B < 2000 µm 977 µm screen C < 1000 µm 140 µm screen D < 140 µm E < 1000 µm µm 977 µm screen F < 1000 µm < 977µm G < 1000 µm 101

120 Tble 3.3 Physico-chemicl properties of brn smples Prticle size nd distribution ( m) A B C D E F G Men size ± ±29.4b 666.5±5.6d 108.9±0.4e 663.8±8.5d 654.2±2.0d ±5.9c Volume (%) d ± ±6.3b 148.9±3.5d 11.4±0.0e 134.2±0.1d 131.6±2.6d 453.4±5.0c d ± ±16.0b 370.1±5.6d 31.9±0.2e 339.3±0.2d 342.2±4.1d 722.4±6.2c d ± ±24.4b 674.4±5.6d 106.4±0.2f 629.0±4.8e 623.2±2.6e ±5.1c d ± ± ±6.7c 165.2±0.6d 925.5±11.2c 912.3±2.7c ±6.6b d ± ±49.6b ±8.6c 216.5±1.0d ±23.4c ±13.8c ±9.4b Chemicl composition (%) Protein 16.72± ± ± ± ± ± ±0.01 Lipid 0.56±0.06bc 0.58±0.06bc 0.86±0.06b 0.84±0.07b 1.11± ± ±0.02b Crude fiber 21.13±0.16b 21.09±0.84b 30.93±0.04b 34.36± ±5.12b 35.44± ±0.31b Ash 5.84±0.30c 6.04±0.05bc 6.12±0.22bc 7.57± ±0.24b 5.71±0.17c 4.93±0.10d *Protein= n x 6.25 fctor Dt re men of duplictes ± stndrd devition. Vlues within the row with the sme letter re not significntly different from ech other t p

121 Tble 3.4 Slope of storge (G ) nd loss (G ) moduli versus frequency curves of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement level t constnt wter bsorption. Strong (S) Flour Slope of G Slope of G Wek (W) Flour Slope of G Slope of G No brn c No brn b SA bc WA b SA WA SB bc WB b SB bc WB b SC c WC b SC bc WC SD b 0.242bc WD b SD b 0.259bc WD b SE bc WE b SE b 0.270bc WE SF bc WF b SF b 0.260bc WF b SG bc WG b SG b 0.301b WG Vlues with the sme letter in column re not significntly different from ech other t p S-Strong Flour, W-Wek flour, A-G- Brn types, G -Storge modulus, G -Loss modulus. 103

122 Tble 3.5 Slope of storge (G ) nd loss (G ) moduli versus frequency curves of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement t optimum wter bsorption. Strong (S) Flour Slope of G Slope of G Wek (W) Flour Slope of G Slope of G No brn bcde No brn b SA b 0.265b WA b SA cd WA b SB b 0.238bcde WB b SB bc 0.260bcd WB b SC b 0.229de WC b SC bc 0.256bcd WC b SD bc 0.241bcde WD b 0.248b SD d 0.264bc WD SE b 0.243bcde WE b SE b 0.240bcde WE b SF b 0.240bcde WF b SF b 0.216e WF b SG bc 0.231cde WG b SG bc 0.256bcd WG Vlues with the sme letter in column re not significntly different from ech other t p S-Strong Flour, W-Wek flour, A-G- Brn types, G -Storge modulus, G -Loss modulus. 104

123 Tble 3.6 Pek storge (G ) nd loss (G ) moduli, temperture t which pek G ws ttined (T G mx ) nd pek viscosity ( *) of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement level t optimum wter bsorption. Strong (S) flour Pek G (P) Pek G (P) T G mx ( C) Pek (P.s) Wek (W) flour Pek G (P) Pek G (P) T G mx ( C) Pek (P.s) No brn 1.26E+05b 4.59E c 2.15E+04 No brn 1.15E E e 1.92E+04 SA E+05b 3.67E d 1.75E+04 WA E E i 2.08E+04 SA E+05b 3.45E E+04 WA E E d 2.38E+04 SB E+05b 3.41E E+04 WB E E f 1.94E+04 SB E+05b 3.86E b 2.05E+04 WB E E e 2.17E+04 SC E+05b 4.62E c 1.85E+04 WC E E b 2.08E+04 SC E+05b 3.27E c 1.88E+04 WC E E d 2.00E+04 SD E+05b 4.26E bc 2.00E+04 WD E E b 1.92E+04 SD E+05b 3.32E c 1.84E+04 WD E E b 2.04E+04 SE E+05b 2.88E E+04 WE E E h 2.56E+04 SE E+05b 3.44E b 1.83E+04 WE E E c 1.98E+04 SF E+05b 3.00E b 1.69E+04 WF E E h 1.97E+04 SF E+05b 4.13E b 2.17E+04 WF E E g 1.74E+04 SG E+05b 6.35E E+04 WG E E e 1.95E+04 SG E E b 2.31E+04 WG E E E+04 Vlues with the sme letter in column re not significntly different from ech other t p S-Strong Flour, W-Wek flour, A-G- Brn types, G -Storge modulus, G -Loss modulus, T-Temperture, *-Complex viscosity. 105

124 Tble 3.7 Creep nd recovery prmeters of strong (S) nd wek flour (W) doughs with respect to brn types nd replcement t optimum wter bsorption. Strong (S) flour J mx 10-3 (1/P) J e 10-3 (1/P) J e /J mx rtio Wek (W) flour J mx 10-3 (1/P) J e 10-3 (1/P) J e /J mx rtio No brn 0.631bc 0.354bcd No brn SA bc 0.364bc WA bcd 0.571cde SA cde 0.258cd WA def 0.460ef SB bcd 0.329bcd WB b 0.734b SB bcd 3.62bcd WB def 0.469def SC WC bc 0.642bc SC bcd 0.349bcd WC cde 0.519cde SD cde 0.283bcd WD bcd 0.606bcd SD e 0.236d WD f 0.317g SE b 0.388b WE bcd 0.590cde SE bc 0.376bc WE cde 0.533cde SF bcde 0.301bcd WF bcd 0.579cde SF cde 0.286bcd WF def 0.453ef SG cde 0.259cd WG bcde 0.510cde SG de 0.263bcd WG ef 0.336g Vlues with the sme letter in column re not significntly different from ech other t p 0.05 J mx -Mximum complince, J e -Elstic complince, J e /J mx -Elstic prt of the mximum creep complince. 106

125 Tble 3.8 Anlysis of Vrince (ANOVA) Tukey test results. Solvent Retention Cpcity Test W-SRC Su-SRC SC-SRC LA-SRC Source p vlue Brn Effect <.0001 RL Effect <.0001 <.0001 Brn*RL Interction P vlues re significntly different t p 0.05 RL-Replcement level SRC-Solvent Retention Cpcity, W-Wter, Su-Sucrose, SC-Sodium crbonte, LA-Lctic cid. b. Mixogrph Test (Constnt WA) Strong Flour Wek Flour Pek Time Pek Height Pek Time Pek Height Source p vlue Brn Effect < <.0001 RL Effect <.0001 Brn*RL Interction < P vlues re significntly different t p 0.05 RL-Replcement level c. Mixogrph Test (Optimum WA) Strong Flour Wek Flour Pek Time Pek Height Pek Time Pek Height Source p vlue Brn Effect < <.0001 RL Effect <.0001 < <.0001 Brn*RL Interction P vlues re significntly different t p 0.05 RL-Replcement level 107

126 d. Frinogrph Test Strong Flour Wek Flour WA DDT Stbility WA DDT Stbility Source p vlue Brn Effect < <.0001 <.0001 <.0001 <.0001 RL Effect < <.0001 <.0001 <.0001 <.0001 Brn*RL Interction < <.0001 <.0001 P vlues re significntly different t p 0.05 RL-Replcement level, WA-Wter bsorption, DDT-Dough development time Strong Flour e. Frequency Sweep Test (Constnt WA) Wek Flour G t 1Hz G slope G t 1Hz G slope G t 1Hz G slope G t 1Hz G slope Source p vlue Brn Effect RL Effect < < < < Brn*RL Interction P vlues re significntly different t p 0.05 RL-Replcement level, G -Storge modulus, G -Loss modulus Strong Flour f. Frequency Sweep Test (Optimum WA) Wek Flour G t 1Hz G slope G t 1Hz G slope G t 1Hz G slope G t 1Hz G slope Source p vlue Brn Effect <.0001 <.0001 <.0001 <.0001 < < RL Effect <.0001 <.0001 < < Brn*RL Interction P vlues re significntly different t p 0.05 RL-Replcement level, G -Storge modulus, G -Loss modulus 108

127 Strong Flour g. Temperture Sweep Test (Optimum WA) Wek Flour Pek G Pek G Pek T Pek * Pek G Pek G Pek T Pek * Source p vlue Brn Effect < < RL Effect < Brn*RL Interction < < P vlues re significntly different t p 0.05 RL-Replcement level, T-Temperture, *-Complex viscosity, G -Storge modulus, G -Loss modulus h. Creep nd Creep Recovery Test (Optimum WA) Strong Flour Wek Flour J mx J e J e /J m x J mx J e J e /J mx Source p vlue Brn Effect < <.0001 < RL Effect <.0001 < Brn*RL Interction P vlues re significntly different t p 0.05 RL-Replcement level, J mx -Mximum complince, J e -Elstic complince, J e /J mx -Elstic prt of the mximum creep complince. i. Unixil Extension Test (Constnt WA) Strong Flour Wek Flour R mx E R mx E Source p vlue Brn Effect <.0001 <.0001 <.0001 <.0001 RL Effect <.0001 <.0001 <.0001 Brn*RL Interction < <.0001 <.0001 P vlues re significntly different t p 0.05 RL-Replcement level, R mx -Mximum resistnce, E-Extensibility. 109

128 j. Unixil Extension Test (Optimum WA) Strong Flour Wek Flour R mx E R mx E Source p vlue Brn Effect <.0001 <.0001 <.0001 <.0001 RL Effect <.0001 <.0001 <.0001 Brn*RL Interction < < P vlues re significntly different t p 0.05 RL-Replcement level, R mx -Mximum resistnce, E-Extensibility. 110

129 Volume (%) Volume (%) A B C D () Prticle size ( m) E F G Prticle size ( m) (b) Figure 3.1 Prticle size distribution of the brn smples. 111

130 SC-SRC (%) LA-SRC (%) W-SRC (%) Su-SRC (%) b b b b 200 b bc bc c 100 c 100 d 0 S A B C D E F G 0 S A B C D E F G () 400 Flour Ctegory-I Ctegory-II (b) 400 Flour Ctegory-I Ctegory-II 300 b b 300 b b 200 c c c c 200 c d cd d 100 d 100 e 0 S A B C D E F G Flour Ctegory-I Ctegory-II (c) (d) Figure 3.2 Solvent retention cpcity (SRC) of strong (S) flour nd brn smples. () Wter SRC, (b) Sucrose SRC, (c) Sodium crbonte SRC, (d) Lctic cid SRC. Vlues with the sme letter re not significntly different from ech other t p S A B C D E F G Flour Ctegory-I Ctegory-II

131 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 SC-SRC(%) LA-SRC(%) S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 W-SRC (%) Su-SRC (%) b b b b b b b b b b b b b b () b b b Ctegory-I b b b b b b Ctegory-II b b b b b (b) b def b Ctegory-I bc ef def cd f bc f Ctegory-II bc b def cde Ctegory-I Ctegory-II (c) (d) Figure 3.3 Solvent retention cpcity (SRC) of strong (S) flour t 5 nd 10% brn replcement levels. () Wter SRC, (b) Sucrose SRC, (c) Sodium crbonte SRC, (d) Lctic cid SRC. Vlues with the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II

132 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Pek time (min) Pek height (%) S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Pek time (min) Pek height (%) c bc bc bc bc bc bc bc bc bcd c bc bc b bc bc c b bc bc b bc b b bc bc 4 30 () 7 6 Ctegory-I Ctegory-II (b) efg h hg fg Ctegory-I cde defg defg b cdef def def Ctegory-II bc bcd defg Ctegory-I Ctegory-II (c) (d) Figure 3.4 Mixogrph prmeters of flour smples t 5 nd 10% brn replcement levels t constnt wter bsorption. () Pek time, strong (S) flour, (b) Pek height, strong (S) flour, (c) Pek time, wek (W) flour, (d) Pek height, wek (W) flour. Vlues with the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II

133 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Pek time (min) Pek height (%) S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Pek time (min) Pek height (%) e bcd cde b bc cde cd cde cd bcd de bc bc bcd def f d ef cd def def def bc bcd b d de def 4 30 () 7 Ctegory-I Ctegory-II (b) 45 Ctegory-I Ctegory-II 6 40 bcde ef b f def bcd ef cdef cdef b bcdef bc bcde f Ctegory-I Ctegory-II (c) (d) Figure 3.5 Mixogrph prmeters of flour smples t 5 nd 10% brn replcement levels t optimum wter bsorption. () Pek time, strong (S) flour, (b) Pek height, strong (S) flour, (c) Pek time, wek (W) flour, (d) Pek height, wek (W) flour. Vlues with the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II

134 116 () S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Ctegory-I Ctegory-II Wter bsorption (FU) bc b e bc ef ef bc ef f g cd de bc ef (b) W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Ctegory-I Ctegory-II Wter bsorption (FU) de b d de de bc de bc f e c b bc b (c) S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Ctegory-I Ctegory-II Development time (min) b (d) W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Ctegory-I Ctegory-II Development time (min) b d cd e bc b b e bcd e e bcd bcd e

135 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Stbility (min) Stbility (min) f bc ef bcd bc b b bc bc bc cde bcd def 12 8 d b d bc b bc b b bc b b b c Ctegory-I Ctegory-II Ctegory-I Ctegory-II (e) (f) Figure 3.6 Frinogrph prmeters of flour smples t 5 nd 10% brn replcement levels. () Wter bsorption, strong (S) flour, (b) Wter bsorption, wek (W) flour, (c) Development time, strong (S) flour, (d) Development time, wek (W) flour, (e) Stbility, strong (S) flour, (f) Stbility, wek (W) flour. Vlues with the sme letter re not significntly different from ech other t p

136 Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) 1.E+05 1.E+05 1.E+04 1.E+04 () SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SE10 SF05 SF10 SG05 SG10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+04 1.E+04 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 1.E+03 W 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.7 Storge modulus (G ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory- II brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption. 118 WE05 WE10 WF05 WF10 WG05 WG10 1.E+03 W 1.E-01 1.E+00 1.E+01

137 Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) 1.E+05 1.E+05 1.E+04 1.E+04 () SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SE10 SF05 SF10 SG05 SG10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+04 1.E+04 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 1.E+03 W 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.8 Storge modulus (G ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory- II brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption. 119 WE05 WE10 WF05 WF10 WG05 WG10 1.E+03 W 1.E-01 1.E+00 1.E+01

138 Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) 1.E+05 1.E+05 1.E+04 1.E+04 () SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SE10 SF05 SF10 SG05 SG10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+04 1.E+04 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 W 1.E+03 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.9 Loss modulus (Gʺ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption. 120 WE05 WE10 WF05 WF10 WG05 WG10 1.E+03 W 1.E-01 1.E+00 1.E+01

139 Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) 1.E+05 1.E+05 1.E+04 1.E+04 () SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SE10 SF05 SF10 SG05 SG10 1.E+03 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+04 1.E+04 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 W 1.E+03 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.10 Loss modulus (Gʺ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory- II brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption. 121 WE05 WF10 WE10 WG05 WF05 WG10 W 1.E+03 1.E-01 1.E+00 1.E+01

140 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Storge modulus (G') t 1 Hz Loss modulus (G") t 1 Hz S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Storge modulus (G') t 1 Hz Loss modulus (G") t 1 Hz 4.E+04 4.E+04 3.E+04 2.E+04 1.E+04 e bcd de b bcd bc bcd bcd bcd cde bcde bcde bcd b 3.E+04 2.E+04 1.E+04 d bcd b cd bcd cd bcd bc b bc bcd bcd cd bcd 0.E+00 0.E+00 () 4.E+04 b Ctegory-I Ctegory-II (b) 4.E+04 Ctegory-I Ctegory-II 3.E+04 2.E+04 1.E+04 c bc bc bc bc bc bc bc bc bc bc bc bc 3.E+04 2.E+04 1.E+04 d bcd bcd bcd bcd bc bcd b d bcd cdbcd bcd bcd 0.E+00 0.E+00 Ctegory-I Ctegory-II (c) (d) Figure 3.11 Storge (G ) nd loss (G ) moduli t 1 Hz frequency. () G of strong (S) flour, (b) G of strong (S) flour, (c) G of wek (W) flour, nd (d) G of wek (W) flour t 5 nd 10% brn replcement levels t constnt wter bsorption Vlues with the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II

141 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Storge modulus (G') t 1 Hz Loss modulus (G") t 1 Hz S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Storge modulus (G') t 1 Hz Loss modulus (G") t 1 Hz 4.E+04 4.E+04 3.E+04 2.E+04 1.E+04 g bc ef b bc def bcd fg ef fg bc bcde cdef 3.E+04 2.E+04 1.E+04 d bcd b cd cd bc bc cd cd cd cd bcd cd 0.E+00 0.E+00 () 4.E+04 Ctegory-I Ctegory-II (b) 4.E+04 Ctegory-I Ctegory-II 3.E+04 2.E+04 1.E+04 bcd d bcd cd bcd bcd b bcd bcd bcd bcd bc bcd 3.E+04 2.E+04 1.E+04 d bcd d bcd cd bc d bcd b bcd bcd bcd bcd bc bc 0.E+00 0.E+00 Ctegory-I Ctegory-II (c) (d) Figure 3.12 Storge (G ) nd loss (Gʺ) moduli t 1 Hz frequency. () G of strong (S) flour, (b) G of strong (S) flour, (c) G of wek (W) flour, nd (d) G of wek (W) flour t 5 nd 10% brn replcement levels t optimum wter bsorption. Vlues the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II

142 Tn delt ( ) Tn delt ( ) Tn delt ( ) Tn delt ( ) SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD SE05 SF05 SG05 S SE10 SF10 SG () E-01 1.E+00 1.E+01 Frequency (Hz) 1.5 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD W (b) E-01 1.E+00 1.E+01 Frequency (Hz) 1.5 WE05 WE10 WF05 WF10 WG05 WG10 W E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.13 Tngent delt ( ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption E-01 1.E+00 1.E+01

143 Tn delt ( ) Tn delt ( ) Tn delt ( ) Tn delt ( ) SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD SE05 SF05 SG05 S SE10 SF10 SG () E-01 1.E+00 1.E+01 Frequency (Hz) 1.5 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD W (b) E-01 1.E+00 1.E+01 Frequency (Hz) 1.5 WE05 WE10 WF05 WF10 WG05 WG10 W E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.14 Tngent delt ( ) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption E-01 1.E+00 1.E+01

144 Complex viscosity, * (p.s) Complex viscosity, * (p.s) Complex viscosity, * (p.s) Complex viscosity, * (p.s) 1.E+05 1.E+05 1.E+03 1.E+03 () SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 1.E+01 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SF10 SE10 SG05 SF05 SG10 1.E+01 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+03 1.E+03 WA05 WB10 WB05 WA10 WC05 WC10 WD05 WD10 1.E+01 W 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.15 Complex viscosity ( *) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t constnt wter bsorption. 126 WE05 WE10 WF05 WF10 WG05 WG10 1.E+01 W 1.E-01 1.E+00 1.E+01

145 Complex viscosity, * (p.s) Complex viscosity, * (p.s) Complex viscosity, * (p.s) Complex viscosity, * (p.s) 1.E+05 1.E+05 1.E+03 1.E+03 () SA05 SC05 SA10 SC10 SB05 SD05 SB10 SD10 1.E+01 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 (b) SE05 SF10 SE10 SG05 SF05 SG10 1.E+01 S 1.E-01 1.E+00 1.E+01 Frequency (Hz) 1.E+05 1.E+03 1.E+03 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 1.E+01 W 1.E-01 1.E+00 1.E+01 (c) Frequency (Hz) (d) Frequency (Hz) Figure 3.16 Complex viscosity ( *) versus frequency plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption. 127 WE05 WE10 WF05 WF10 WG05 WG10 1.E+01 W 1.E-01 1.E+00 1.E+01

146 Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) Storge modulus, G' (P) 1.E+06 1.E+06 1.E+05 1.E+05 () 1.E+04 1.E+03 1.E+06 SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 S Temperture ( C) (b) 1.E+04 1.E+03 1.E+06 SE05 SE10 SF05 SF10 SG05 SG10 S Temperture ( C) 1.E+05 1.E+05 1.E+04 WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 1.E+03 W (c) Temperture ( C) (d) Temperture ( C) Figure 3.17 Storge modulus (G ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption E+04 WE05 WF10 WE10 WG05 WF05 WG10 W 1.E

147 Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) Loss modulus, G" (P) 1.E+06 1.E+05 SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD10 1.E+06 1.E+05 SE05 SF05 SG05 S SE10 SF10 SG10 1.E+04 1.E+04 () 1.E+03 1.E+06 1.E Temperture ( C) WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 W (b) 1.E+03 1.E+06 1.E Temperture ( C) WE05 WF10 WE10 WG05 WF05 WG10 W 1.E+04 1.E+04 1.E (c) Temperture ( C) (d) Temperture ( C) Figure 3.18 Loss modulus (Gʺ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption E

148 Tn delt ( ) Tn delt ( ) Tn delt ( ) Tn delt ( ) 1.0 SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD SE05 SF05 SG05 S SE10 SF10 SG () Temperture ( C) WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 W (b) Temperture ( C) WE05 WF10 WE10 WG05 WF05 WG10 W (c) Temperture ( C) (d) Temperture ( C) Figure 3.19 Tngent delt ( ) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory- II brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption

149 Complex viscosity, * (P.s) Complex viscosity, * (P.s) Coplex viscosity, * (P.s) Coplex viscosity, * (P.s) 1.E+05 SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD10 1.E+05 SE05 SF05 SG05 S SE10 SF10 SG10 1.E+04 1.E+04 () 1.E+03 1.E Temperture ( C) WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 W (b) 1.E+03 1.E Temperture ( C) WE05 WE10 WF05 WF10 WG05 WG10 W 1.E+04 1.E+04 1.E (c) Temperture ( C) (d) Temperture ( C) Figure 3.20 Complex viscosity ( *) versus temperture plots for () strong (S) flour, ctegory-i brns, (b) strong (S) flour, ctegory-ii brns, (c) wek (W) flour, ctegory-i brns, d) wek (W) flour, ctegory-ii brns t 5 nd 10% replcement levels t optimum wter bsorption E

150 Creep complince, J(t) Creep complince, J(t) 1.5E E E-04 SA05 SB05 SC05 SD05 S SA10 SB10 SC10 SD10 6.0E E-04 () 0.0E Time (sec) 1.5E E E-04 SE05 SF05 SG05 S SE10 SF10 SG10 6.0E E E (b) Time (sec) 132

151 Creep complince, J(t) Creep complince, J(t) 1.5E E-03 WA05 WB05 WC05 WD05 W WA10 WB10 WC10 WD10 9.0E E E-04 (c) 0.0E E E Time (sec) WE05 WE10 WF05 WF10 WG05 WG10 W 9.0E E E E Time (sec) (d) Figure 3.21 Creep nd recovery profiles of strong nd wek flours t 5 nd 10% brn replcement levels t optimum wter bsorption. () Strong (S) flour, ctegory-i brns, (b) Strong (S) flour, ctegory-ii brns, (c) Wek (W) flour, ctegory-i brns, (d) Wek (W) flour, ctegory-ii brns 133

152 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 W fl. WA05 WA10 WB05 WB10 WC05 WC10 WD05 WD10 WE05 WE10 WF05 WF10 WG05 WG10 Mximum resistnce, Rmx (g) Extensibility, E (mm) S fl. SA05 SA10 SB05 SB10 SC05 SC10 SD05 SD10 SE05 SE10 SF05 SF10 SG05 SG10 Mximum resistnce, Rmx (g) cd bc cd b cd cd bc d cd bc cd cd cd () 40 Ctegory-I Ctegory-II (b) g cde cde cde bc def cd fg b cde cde cde ef defg g cde efg b g bcd def b g bc fg efg fg (c) Ctegory-I Ctegory-II (d) Figure 3.22 Unixil extensionl properties. () Rmx of strong (S) flour, (b) E of strong (S) flour, (c) Rmx of wek (W) flour, (d) E of wek (W) flour t 5 nd 10% brn replcement levels t constnt wter bsorption Vlues with the sme letter re not significntly different from ech other t p Ctegory-I Ctegory-II