UNIVERSITI PUTRA MALAYSIA MODIFICATION AND IMPROVEMENT OF KHAO KRIAP WAUE' (A TRADITIONAL THAI GLUTINOUS RICE-BASED SNACK FOOD) SOMCHAI JOMDUANG FSMB 1994 7
MODIFICATION AND IMPROVEMENT OF tkhao KRIAP WAUE' (A TRADITIONAL THAI GLUTINOUS RICE-BASED SNACK FOOD) By SOMCHAI JOMDUANG Dissertation Submitted in Fulfilment of the Requirements for the Degree of Doctor of Philosophy at the Faculty of Food SCience and Biotechnology, Universiti Pertanian Malaysia. July 1994
Dedicated to my wife, Mrs. Jinantana Jomduang for her understanding and encouragement which has been a constant source of inspiration.
ACKNOWLEDGEMENTS I would like to express sincere gratitude to my chairman, Associate Professor Dr. Suhaila Mohamed, for her understanding, patience, invaluable guidance, suggestions, constructive criticisms and constant encouragement throughout the planning and execution of this research. My deep appreciation and gratitude go to Dr. Abdullah Abu Bakar and Dr. Kharidah Muhammad, members of supervisory committee, for guidance and suggestions. wish to thank the Dean and all the members of the Faculty of Food Science and Biotechnology, UPM, for providing facilities and technical assistance during the course of my study. I would also like to extend my thanks to Mr. Abdul Aziz Bahsir and Miss Fadzlon Mohd. Yusof from Graduate School, UPM who gave me invaluable assistance with regard to the requirements of the thesis format. My sincere gratitude is also extended to Rajamangala I nstitute of Technology (RIT), Ministry of Education, Thailand, for granting the study leave and providing the necessary research fund during my study. Last but not least,, am greatly indebted to my beloved parents and family members, particularly to my wife, fo r their understanding and encouragement throughout the course of this study. iii
I would also like to thank all my friends who gave me a great deal of encouragement to initiate and complet the study. To these and all others who have helped during this study, I wish to express deepest appreciation. iv
TABLE OF CONTENTS Page ACKMOWLEDGEMENTS LIST OF TABLES LI ST OF FIGURES LIST OF PLATES iii xi xiii xvi LIST OF ABBREVIATIONS................ xvi i i ABSTRACT ABSTRAK xx xxiii CHAPTER I I NTRODUCT I ON............... 1 I I LITERATURE REVIEW..... 14 Definition and Classification of Snack Foods................................... 14 Traditional Process for Preparation of Snack Foods................................ 15 Modern Processing of Snack Foods 17 Extrusion Process 17 Microwave Oven 20 Rice as a Starchy Material for Snack Foods 23 Starch and Starch Gelatinisation 25 Flavours and Colours for Snack Foods 31 Nutrition and Nutrification of Snack Foods 32 Soybean as an Important Protein Source for Snack Fortification....................... 36 v
Page Water Activity and Mould Growth in Intermediate Moisture Foods 37 Packaging and Keeping Quality of Snack Foods........ 41 III BASIC STUDY ON tkhao KRIAP WAUE' PROCESS 44 Introduction 44 Materials and Methods 45 Starchy Materials and Traditional KKW Samples................................ 45 Determination of Chemical Composition 45 Determination of Flour Characteristics 46 Preparation of Traditional KKW 47 Process Study of Traditional KKW 49 Measurement of Puffed KKW Characteristics.,. 51 Results and Discussion Chemical Composition of Glutinous Rice Samples Chemical Composition of Traditional KKW Samples Glutinous Rice Grain versus Flour as Raw Material of KKW Effectiveness of Greasing Materials Effect of Steaming Time on Puffed KKW Characteristics Effect of Sucrose Adding Stage on Puffed KKW Characteristics Effect of Pounding on Puffed KKW Characteristics 52 52 53 55 57 59 60 62 vi
Page Effect of Drying on KKW Characteristics Effect of Unpuffed KKW Thickness on Puffed Product Characteristics Summary 64 67 69 IV EFFECT OF INGREDIENTS ON ckhao KRIAP WAUE' CHARACTERISTICS Introduction Materials and Methods Raw Materials and Preparation 71 71 72 72 Proximate Analysis and Amino Acid Determination of Raw Materials 74............. Determination of Flour Characteristics 74 Preparation of KKW 75 Effect of Starchy Materials on KKW Characteristics..................... 76 Effect of Sucrose, Salt and Oil on Puffed KKW Characteristics 77 Effect of Adding Legume Flours, Protein Isolates and Milk Products on Puffed KKW Characteristics............................ 77 Measurement of Puffed KKW Characteristics............................ 77 Sensory Evaluation of Puffed KKW 78 Results and Discussion 78 Chemical and Amino Acid Composition of Raw Materials........................... 78 Physical Properties of Wet Milled and Dry Milled Glutinous Rice Flour 81 vi i
Pqe Effect of Particle Size and Milling Methods on Puffed KKW Characterist ics.............. 85 Apparent Gelatinisation Temperature of Glutinous Rice-Non-glutinous Rice Flour Blends....... 86 Apparent Gelatinisation Temperature of Glutinous Rice-Taploca Flour Blends 86 Effect of Substituting Glutinous Rice Flour with Non-gl utinous Rice Fl our on KKW Characteristics.............. 91 Effect of Substituting Glutinous Rice Flour with Tapioca Fl our on KKW Characteristics 94 Effect of Added Sucrose on Puffed KKW Characteristics 95 Effect of Added Salt on Puffed KKW Characteristics 100 Effect of Added Oil on Puffed KKW Characteristics 102 Effect of Added Proteinaceous Materials on KKW Characteristics..................... 102 Summary 112 v PROCESS MODIFICATION OF ckhao KRIAP WAllE'.... 115 Introduction 115 Materials and Methods 116 Preparation of KKW 116 Process Modifications 116 Determination of Pasting Characteristics 119 Measurement of Puffed KKW Characteristics 119 Results and Discussion 121 viii
Page Pounding Process Modification Using a Dough Ml xer.............................. 121 Modification of Sheeting Process Using a Mechanical Roller.................... 124 Modification of Sheeting Process Using a Mechanical Slicer... 127 Modification of Puffing Process Summary 131 140 V I EXTEND I NG TIlE STORAGE L I FE OF "KHAO KRIAP laue'.................... 141 Introduction 141 Materials and Methods 142 Preparation of KKW 142 Effect of Packaging Materials and Butyl Paraben on Keeping Quality of Unpuffed KKW....... 143 Effect of Greasing Materials on Keeping Quality of Unpuffed KKW 145 Effect of Drying Time and Moisture Content on Keeping Quality of Unpuffed KKW.... 145 Effect of Added Sucrose on Water Activity and Keeping Quality of Unpuffed KKW........ 145 Effect of Packaging Materials on Keeping Quality of Puffed KKW.......... 146 Results and Discussion................. 147 Effect of Packaging Materials and Butyl Paraben on Keeping Quality of Unpuffed KKW......... 147 Effect of Greasing Materials on Keeping Quality of Unpuffed KKW......... 153 Effect of Drying Time on Moisture Content and Keeping Quality of Unpuffed KKW........ 153 ix
Page Effect of Added Sucrose on Water Activity and Keeping Quality of Unpuffed KKW..... 158 Effect of Packaging Materials on Keeping Quality of Puffed KKW...... 160 Summary 163 VII GENERAL DISCUSSION AND CONCLUSION......... 165 BIBLIOGRAPHY................. t 73 APPENDIX A Determination of Starch 188 B Determination of Amylose 191 C Determination of Amino Acids 197 D Determination of Apparent Gelatinisation Temperature of Starchy Materials...... 209 E Determination of Water Activity (aw) 212 F Statistical Analysis for Sensory Evaluation 215 G Statistical Analysis Data of Puffed KKW Characteri st i cs............................... 225 PUBLICATION 231 VITA 241 x
LIST OF TABLES Table 1 Chemical Composition of Some Glutinous Rice Grains and Flours 54.......................... Page 2 Chemical Composition of Some Traditional KKW Samples......................... 55 3 Comparison of the Use of Glutinous Rice Grain and Glutinous Rice Flour as KKW Raw Materials........... 56 4 Comparison of Intermediate Moisture KKW Characteristics Resulting from Sun Drying and Hot Air Drying......................... 68 5 Effect of Unpuffed Thickness on Puffed KKW Characteristics..................... 68 6 Chemical Composition of Some KKW Raw Materials 7 Comparison of Some Essential Amino Acid Contents in KKW Raw Materials 81................... 8 Effect of Wet and Dry Milled Flour and Flour Particle Size on Puffed KKW Characteristics................... 83 9 Protein Content, Starch Components and Apparent Gelatinisation Temperature of Various Starch Flours and Starch Flour Blends 88............ 10 Regression Analysis of Apparent Gelatinisation Temperature (V i ) in Relation to Various Independent Variables (X i ) 89...................... 11 Effect of Partially Substituted Glutinous Rice Flour with Non-glutinous Rice Flour and Tapioca Flour on Puffed KKW Characteristics 92............. 12 Regression Analysis of Non-glutinous Rice and Tapioca-mixed Puffed KKW Characteristics (V i ) in Relation to Various Independent Variables (X i > 93... 13 Sensory Evaluation of Puffed KKW Added with Sucrose and Salt 100........................... 80 xi
Table Page 14 Effect of Proteinaceous Materials and Milk Products Addition on Puffed KKW Characteristics...... 105 15 Sensory Evaluation of KKW Products Added with Some Proteinaceous Materials and Milk Products... 109 16 Essential Amino Acid Content of Some Blended Flours Added with Various Types of Proteinaceous Materials and Milk Products........ 113 17 Puffing Time and Puffed KKW Characteristics from Various Puffing Methods........... 132 18 Effect of Puffing Methods on Puffed KKW Characteristics...... 134 19 Regression Analysis of Water Activity in Relation to Moisture Content (X i ) of Intermediate Moisture KKW at Various Amounts of Added Sucrose (V i ) 161 20 Comparison of the Traditional Process and Modified Processes of KKW...... 171 21 Concentration Report of Amino Acid Profile Using PICa. TAG Method.................... 207 22 Amino Acid Content in Some KKW Raw Materials 208 23 Relative Humidity of Some Saturated Sal t So 1 uti ons................................. 214 24 lists of Rank Totals for Ranking Analysis 25 Ranked Data Scores for Raw Data Conversion 223 224 26 Effect of teaming Time on Puffed Product Characteristics.......... 226 27 Effect of Unpuffed Product Moisture Content from Hot Air Drying (45 C) on Puffed Product Characteristics................................ 227 28 Effect of Sucrose, Salt and Oil Added on Puffed Product Characteristics... 228 29 Moisture Content and Puffed Quality of KKW from Various Treatments during Storage Time...... 230 xii
LIST OF FIGURES Figure Page 1 Flow Chart of the Traditional Process for 'Khao Kriap Waue' (KKW)... 11 2 Effect of Steaming Time on Puffed KKW Characteristics....... 59 3 Effect of Stage at Which Sucrose Is Added into Dough on Puffed KKW Characteristics 61 4 Effect of Pounding on Puffed KKW Characteri st i cs............................... 63 5 Brabender Amylograph of Flour Obtained from Pounded and Un pounded Dough in KKW Processing 64 6 Drying Curve of KKW at 45, 50 and 55 C in a Hot Air Dryer.............. 65 7 Effect of Moisture Content of Unpuffed KKW Dried by a Hot Air Dryer (50 C) on Puffed KKW Characteristics... 66 8 Brabender Amylograph of Glutinous Rice Flour from Wet and Dry Milling Processes... 84 9 Brabender Amylograph of Different Types and Particle Sizes of Glutinous Rice Flour 84 10 Brabender Amylograph of Glutinous Rice Flour, Non-glutinous Rice Flour and Various Proportions of Blended Flours............................. 87 11 Brabender Amylograph of Glutinous Rice Flour, Tapioca Flour and Various Proportions of Blended Flours......... 90 12 Brabender Amylograph of Glutinous Rice Flour Added with Sucrose, Salt and Oil... 96 13 Puffed Characteristics of KKW Containing Various Amounts of Sucrose...................... 97 14 Puffed Characteristics of KKW Containing Various Amounts of Salt... 101 xiii
Figure Page 15 Puffed Characteristics of KKW Containing Various Amounts of Oil 103 16 Brabender Amylograph of Glutinous Rice Flour Added with Some Legume Flours.......... 108 17 Brabender Amylograph of Glutinous Rice Flour Added with Some Protein Isolates and Skim Mil k Powder............................ 111 18 Effect of Various Dough Mixing Techniques on Amylograph Profile of Starch............ 122 19 Characteristics of Puffed KKW Produced Using Manual and Modified Pounding Methods............ 123 20 Characteristics of Puffed KKW Produced Using Mechanical and Manual Rolling......... 125 21 Characteristics of Puffed KKW Produced by Slicing after Being Kept at Various Temperatures as Compared to That Produced Using the Traditional Method.............. 130 22 Effect of Packaging Materials and Butyl Paraben on Mould Growth of Unpuffed KKW during Storage Time.......................... 148 23 Effect of Packaging Materials on (a) Moisture Content and (b) Mould Growth of Unpuffed KKW during Storage Time... 149 24 Puffed Product Characteristics of Intermediate Moisture KKW Packed in Various Packaging Materials during Storage Time............ 151 25 Effect of Vacuum Packing on Puffed Product Characteristics of Intermediate Moisture KKW during Storage Time................ 152 26 Effect of Greasing Materials on Moisture Content and Mould Growth of Unpuffed KKW during Storage Time.................... 154 27 Effect of Drying Time on (a) Moisture Content and (b) Mould Growth of Unpuffed KKW Packed in lope during Storage Time... 155 xiv
Figure 28 Effect of Drying Time on Puffed KKW Characteristics during Storage T;.e Page 157 29 Effect of Drying Time and Amount of Added Sucrose on Moisture Content and Toughness (Instron Curve)- of Intermediate Moisture KKW............ 159 30 Correlation between Moisture Content and Water Activity ( ) of Intermediate Moisture KKW from Various Amounts of Added Sucrose 161 31 Moisture Content and Hardness of Puffed KKW Kept in Various Types of Packagi n9 Mater i a 1... 163 32 Flow Chart of Modified Process A for 'Khao Kriap Waue' (KKW)...... 169 33 Flow Chart of Modified Process B for 'Khao Kriap Waue' (KKW)......... 170 34 Print-out of Amino Acid Profile Using PICa. TAG Method................................ 206 xv
LIST OF PLATES Plate 1 The Traditional Method for Glutinous Rice Cooking Using a Steamer Made from Bamboo Page 7 2 A Traditional Wooden Pounding Equipment for KKW Production... 8 3 The Traditional Manual Rolling Method for KKW Production.............................. 9 4 Traditional Puffing of KKW by Roasting Directly on Flame (Upper) and Size Comparison between Unpuffed and Puffed KKW (Lower)...... 10 5 Traditional Wooden Mortars (Upper) and a Laboratorial Cement Mortar (Lower) for KKW Dough Mixing and Pounding... 48 6 Puffed Product of KKW Added with Various Amounts of Sucrose... 98 7 8 9 10 Comparison of Puffed KKW Added with 40 g Sucrose/100 g Flour A Dough Mixer (Upper) and a Sheeting Machine (Lower) Used for KKW Process Modification A Mechanical Slicer (Upper) and a Stuffer (Lower) Used for KKW Process Modification Unpuffed and Puffed KKW Produced Using a Mechanical Roller (Upper) and the Traditional Manual Rolling (Lower) 99 118 120 126 11 Unpuffed and Puffed KKW Obtained from Mod if i ed Sheet i ng Processes.................... 128 12 Various Sizes and Shapes of Unpuffed and Puffed KKW Produced from Application of a Freezer (-5 C) and a Mechanical Slicer 129 xvi
Plate 13 Puffed KKW from Two Roasting Methods Page 133 14 Puffed KKW from Microwave Puffing at Medium and High Power......................... 135 15 Puffed KKW from Oven Puffing and Frying 137 16 Puffed KKW Produced Using a Hot Pan and Hot Sand................... 139 xvii
LIST OF ABBREVIATIONS :'a ANOYA AOAC Arg Asp B.D. em CRO CP Cys d.b. df OMRT OSC E.R. EYM FAO FM G Glu Gly HCl HOPE His Hypo Iso KKW LOPE Leu Lys MB MBI Met N NMR NPU P PE PMR PP POA Phe Pro R R06 water act i vity alanine analysis of variance Association Official of Analytical Chemists argenine aspartic acid bulk density coconut mil k completely randomised design chickpea flour cystein dry basis degree of freedom Duncan's Multiple Range Test differential scanning colorimetry expansion ratio evaporated milk Food and Agriculture Organisation fresh milk glutinous rice flour glutamine glycine hydrochloric acid high density polyethylene histamine hydroxyprolein isoleucine Khao Kriap Waue low density polyethylene leucine lysine mungbean flour mungbean protein isolate methionine nitrogen nuclear magnetic resonance net protein utilisation level of probability polyethylene proton magnetic resonance polypropylene potato dextrose agar phenylalanine proline rice flour Rice Department No. 6 xviii
RH S8 Ser SM SPI T T.R. Temp. Thre TMA Tyr Val w.b. WHO relative humidity soybean flour serine skim mil k powder soy protein isolate tapioca flour thickness ratio t6mperature threonine thermo mechanical analysis tyrosine valine wet basis World Health Organisation xix
Abstract of the dissertation submitted to the Senate of Universiti Pertanian Malaysia in fulfilment of the requirements for the deg ree of Doctor of Philosophy. MODIFICATION AND IMPROVEMENT OF 'KHAO KRIAP WAUE" (A TRADITIONAL THAl GLUTINOUS RICE-BASED SNACK. FOOD) By SOMCHAI JOMDUANG JULY 1994 Chairman Faculty Assoc. Prof. Dr. Suhaila Mohamed Food Science and Biotechnol09Y 'Khao Kriap Waue' (KKW) is a popular Thai snack food made from glutinous rice. Traditional KKW mainly constitutes carbohydrate (92.8%) since its major ingredients are glutinous rice and sugar. Its other chemical constituents are 5.7% protein, 0.7% fat, 0.6% ash and 0.2% crude fibre. KKW has a low fat content and differs from other deep fried snack foods in that it is puffed by roasting, not deep frying. The production of KKW requires several elaborate steps. The glutinous rice grain is soaked, steamed and then pounded with sugar (sucrose), water and caramel to a moisture content of about 50%. The sticky dough is then made into bal ls and manually rolled flat, before sun drying. The intermediate moisture product can be stored for less than a week at room temperature and is puffed by roasting on a direct flame before serving. xx
The labour intensive traditional process could be simplified by using a dough mixer and a mechanical sheeter to replace manual pounding and sheeting. The sticky dough could also be hardened at a low temperature (0-4 C) and mechanically sliced to the optimum thickness of 2 mm. Drying was best done in a 50±5 C hot air dryer for 4 hr to a moisture content of 17±3%. Puffing by D microwave or 225±25 C oven could replace the trad itional direct flame roasting resulting in a good product devoid of burnt spots. The modified technology for KKW production could be utilised at bot h cottage and ind ustrial levels. Wet milled glutinous rice flour was found to be the most suitable raw material for making good quality KKW com pared to dry milled glutinous rice flour, glutinous rice grain, glutinous rice-non-glutinous rice flour mixtures or glutinous rice-tapioca flour mixtures. This is related to the amylopectin content and starch damage of the flour. The optimum salt and sucrose content were 2 g and 15-35 g/100 g flour, respectively which was best added during the pounding process, to improve the puffed product characteristics. Soybean flour, mungbean flour, chickpea flour, legume protein isolate and skim milk powder could be added at 10, 20, 30, 20 and 30 g/100 g flour, respectively to increase the protein content from 6.6% to approximately 10%. The addition of proteinaceous materials also helped to improve the amino acid balance in KKW. Fresh milk and coconut milk when used in place of water improved the appearance and flavour of KKW. xxi
Palm olein:lecithin mixture (20:1 w/w) was superior to the traditional cooking oil:boiled egg yolk mixture for greasing the dough during the sheeting process because it resulted in a cheaper and more microbiologically stable product. The storage life of unpuffed intermediate moisture KKW could be extended to three months in vacuumed packaging before mould growt h was detected. Butyl paraben at 1000 ppm could reduce but not prevent mould growth on KKW during storage. Reducing the moisture content resulted in a brittle unpuffed KKW which did not puff well. Sucrose could be used as a humectant at 35 g/100 g flour to reduce water activity to 0.6 and in extending the storage life of unpuffed KKW to about four weeks. Puffed KKW could be stored in aluminium/polyet hylene lami nates or polypropylene for more than six months without any change in quality. xxii
Abstrak disertasi yang dikemu kakan kepada Senat Universiti Pertanian Malaysia sebagai memenuhi syarat keperluan untuk ijazah Doktor Falsafah MODIFlKASI DAN PENINGKATAN MUTU "KHAO KRIAP WAUE" (SEJENIS MAKANAN SNEK TRADISI THAI YANG BERASASKAN BERAS PULUT) oleh SOMellAI JOMDUANG JULAI 1994 Pengerusi Fakulti Prof. Madya Dr. Suhai la Mohamed Sains Makanan dan Bioteknologi 'Khao Kriap Waue' (KKW) yang diperbuat daripada beras pulut adalah sejenis makanan snek Thailand yang popular. Karbohidrat (92.8%) adalah kandungan utama KKW trad isional ini memandangkan ramuan utamanya hanya terdiri daripada beras pulut dan gula sahaja. Kandungan kimianya yang lain terdiri daripada 5.1% protin, 0.1% lemak, 0.6% abu dan 0.2% serabut kasar. KKW mengandungi kandungan lemak yang rendah berbanding dengan makanan snek lain yang biasanya digoreng dengan minyak; tetapi KKW hanya dikembangkan dengan cara memanggangnya di atas api tanpa menggorengnya di dalam minyak panas. Pemprosesannya melibatkan beberapa cara iaitu beras pulut akan direndam terlebih dahulu, distim, dan kemudiannya tumbuk bersama-sama dengan gula, ai r, dan karamel sehingga kandungan kelembapan mencapai lebih kurang 50%. Doh yang melekit itu akan xxi ii
dibentuk kepada bentuk bebola dan dicanai secara manual sehingga leper, sebelum dikeringkan di bawah cahaya matahari. Produk yang mengandungi kelembapan hayat simpanan kurang daripada yang sederhana ini mempunyai satu minggu pada suhu bilik. lanya disaji bila dikembangkan dengan memanggangnya atas api tanpa berlapik. Proses tradisional boleh dipermudahkan dengan menggunakan mesin penggaul doh dan alat pelembar mekanikal untuk menggantikan penumbukan bahan dan pencanaian secara manual. Doh yang melekit itu boleh dikeraskan pada suhu rendah o (0-4 C) dan dipotong secara mekanikal keketebalan optimum 2 mm. Pengeringan paling berkesan boleh dilakukan di dalam oven pada o suhu 50±5 C selama empat jam sehingga kandungan kelembapan mencapai 17±3%. Pengembangan dengan alat gelombang mikro pad a o 225±25 C ataupun oven ini boleh memberikan produk yang lebih elok di mana kesan-kesan terbakar dapat dikurangkan berbanding dengan cara tradisional. Tepung pulut yang dikisar basah didapati paling sesuai sebagai bahan mentah berbanding dengan tepung pulut dikisar kering, butir-butir beras pulut, campuran tepung pulut dengan tepung beras ataupun campuran tepung pulut dengan tepung ubi kayu untuk menghasilkan KKW yang berkualiti tinggi. I ni boleh dikaitkan dengan kandungan 'amilopektin dan kerosakan kanji di dalam tepung itu. Kandungan optimum garam dan gula ialah xxiv