USE OF THE FARINOGRAPH IN PREDICTING BAKING QUALITY OF UNCHLORINATED AND CHLORINATED FLOURS

Transcription

1 USE OF THE FARINOGRAPH IN PREDICTING BAKING QUALITY OF UNCHLORINATED AND CHLORINATED FLOURS FRANK D. CONFORTII and JANET M. JOHNSON Department of Human Nutrition and Foods Wallace Hall, Room 318 Virginia Polytechnic Institute and State University Blacksburg, VA Accepted for Publication June 17, 1992 ABSTRACT 7he viscoelastic properties of six Coker 9lbjours with different protein contents were analyzed along with their baking properties. 7he wheat grain was grown under different amounts of nitrogen, which resulted in the variation of protein content. A portion of each flour sample was chlorinated, and comparisons were made between viscoelastic properties and baking quality. The farinograph was used to link the data derivedfrom thejour analysis with baking quality. fie stability. mixing tolerance index (MTI) and peak time (Pg correlated significantly with baking pe~ormance and were also good predictors when testing quality of chlorinatedjour. Chlorination increased the absorbency of thejour, which contributed to a firmer crumb and a stable baked product. INTRODUCTION For well over a century, bakers, cereal scientists, cereal food processors, and researchers have been interested in measuring and interpreting the fundamental mechanical properties of wheat flour doughs. Dough texture is not constant. The application of mechanical energy or work to the dough results in changes in the viscoelasticity. There are some alternatives to predict the behavior or property of a flour using the textural properties of the dough. The result has been the evolution of sensitive instruments, such as the farinograph, the mixograph, the extensigraph, the 'Direct all correspondence. Journal of Food Quality 15 (1992) All Rights Reserved. 0 Copyright 1992 by Food & Nutrition Press, Inc., Trumbull, Connecticut. 333

2 334 F.D. CONFORTI and 1.M. JOHNSON amylograph, and the alveograph. These instruments were designed to yield records indicating rheological properties. The data obtained by these instruments are often correlated with the results of baking tests. This type of testing makes it possible to arrive at dependable conclusions concerning the baking quality of the flour under consideration (Faubion and Faridi 1986). The farinograph has been used traditionally in the quality control of flour (Shuey 1984a). The farinograph acts as a sensing device that measures the dough s resistance to mixing during successive stages of its development. At any particular time, dough may be in the process of being stretched, sheared, compressed, or may be in a state of relaxation. Thus the resulting farinograph curve, which is basically a plot of dough resistance against time, represents a combination of all these factors (Preston and Kilborn 1984). Chlorine is widely used in the treatment of soft wheat flour to improve the baking quality (Gough ef al. 1978). Chlorine treatment lowers the ph of the flour and this characteristic serves as a valuable means to control application. The benefits of chlorine treatment of cake flour are outstanding with respect to grain, texture, and volume. The cakes produced can carry higher levels of sugar and shortening than would be possible without treatment (Fortmann and Joiner 1971). The present study was initiated to examine the effectiveness of the farinograph in predicting baking quality. The study s focus was to determine which data points derived from the farinograph can be used as indicators for baking quality in both unchlorinated and chlorinated soft wheat flour. Wheat and Milling MATERIALS AND METHODS Coker 916 was grown by the Department of Crop and Soil Environmental Sciences of Virginia Polytechnic Institute and State University during the growing season for experimental purposes. Six different fertilization treatments of the grain were selected for the study. Different levels of nitrogen were applied to the wheat at growth stages 25 and/or 30 as shown in Table 1 (Zadoks ef al. 1974). The wheat was milled according to the method suggested by the American Association of Cereal Chemists (AACC 1983). Chlorination Half of each milled flour treatment was sent to the Mennel Milling Corporation, Fostoria, OH for chlorination. The final ph of the flour was specified to be (Ash and Colmey 1973).

3 FARINOGRAM: PREDICTING BAKING QUALITY 335 TABLE 1. FERTILIZATION REGIMENS OF COKER 916 Son RED WINTER WHEAT FLOUR TREATMENT NUMBER ~~ NITROGEN TREATMENT (kgnha') AT GROWTH STAGE _- 56 -_- I12 _ 'ha = hectare = 10,000 sq. meters = 2.47 acres. Crude Protein Analysis of Milled Flour Nitrogen content of unchlorinated and chlorinated flours was analyzed by Kjeldahl analysis, AACC method (AACC 1983). Percent protein was expressed by multiplying by a factor of 5.7. Dough Rheological Properties Dough rheological properties were examined by the farinograph (C. W. Brabender Instruments, South Hackensack, NJ) using AACC method constant flour weight procedure for 50 g sample (AACC 1983). The resistance of dough to mixing was evaluated by arrival time (AT), peak time (PT), departure time (DT), stability, and mixing tolerance index (MTI). Angel Food Cakes Angel food cakes were prepared by AACC method (AACC 1983) and baked in a standard household electric oven (P/7, General Electric, Schnectady, NY). Specific gravity of the egg white foam was adjusted to before the final addition of flour. A Hobart electric mixer (K-5A, Troy, OH) connected to a timer control (Universal Timer, Model 17 1, DIMCO Gray Corp., Dayton, OH) was used. All mixing was done in a 5 quart bowl with a wire whip furnished with the mixer.

4 336 F.D. CONFORTI and J.M. JOHNSON Height and Volume Measurements of Angel Food Cakes The height and volume of the angle food cakes were measured as suggested by AACC method (AACC 1983). After 2 h cooling in the tube pan, the cake was depanned and the height (HtD) measured. After an additional 2 h cooling, the height (Hk) was again measured. The Hk measurement was used in the formula for calculating volume (V) of the baked cake with D representing the outside diameter and d representing the inside diameter of the cake. The formula used was Volume (V) =?r Hk(D* - d2) 4 The cake was cut with a serrated knife to minimize deformation. Reproduction of Cake Cells A piece of transparent plastic wrap was stretched tightly over the glass screen of the photocopier (Savin #7350 Copier, Stamford, CT) in order to prevent wrinkles or interference within the copied image. Angel food cakes were cut vertically in half with a serrated knife to prevent cell deformation, and were placed cut side down on the protected screen. The setting criteria were: high contrast, darker copy, number 2. Tenderness The Baker Compressimeter (F. Watkins Corp., Wallace Tiernan, Belleville, NJ) was used to evaluate compression as an index to tenderness. A sample 1 x 1 x 1 cm was cut with a serrated knife from the center of the cake. The compressimeter setting was such that the sample was compressed: (1) a distance of 2.5 cm; (2) the plunger position at 2; and (3) the mechanical advantage of Statistical Analysis Random incomplete block design was used for data collection. All samples were replicated four times. Data were analyzed by the General Linear Model Procedures of the Statistical Analysis System (SAS 1986), using block and flour as the main effects. Flour chlorination and fertilization treatments were compared and treatment standard deviations were calculated. Tukey test was used to separate the means. The predetermined level of probability was 5% and will be used throughout the remainder of this discussion.

5 FARINOGRAM: PREDICTING BAKING QUALITY 3 31 RESULTS AND DISCUSSION Crude Protein Content and ph of Coker 916 Wheat Flour Six Coker 9 16 wheat flour samples of different nitrogen treatments were selected to test their baking quality. The percent of crude protein (Table 2) for each flour was typical of the type of wheat. Coker 916 is a soft red winter wheat that contains a lower amount of protein than hard wheat flour. Soft wheat flour is typically used for cakes, biscuits, crackers, and cookies. There were significant differences (p < 0.05) in protein content among nitrogen treatments. Protein content rose with increased nitrogen fertilization. These findings were in agreement with Terman ef al. (1969), Terman (1979), and Eck (1988). The effect of timing was not significant, but it also was not the focus of this study. Chlorination had no effect on the percent of crude protein. There were no significant differences between the unchlorinated and chlorinated flours except for TRT 7. This does not mean that chlorination did not affect the protein on a molecular level. Tsen and Kulp (1971) found that flour proteins were progressively cleaved by each increment of chlorine as evidenced by the increasing extractability of proteins in water and acetic acid. The authors also found the inter- and intramolecular bonds of the protein molecules were also gradually broken by chlorine, which caused an increase in dispersibility of proteins. TABLE 2. PERCENT (%) CRUDE PROTEIN' CONTENT OF COKER 916 FLOUR UNCHLORINATED FLOUR 1 CHLORINATED FLOUR 'Calculation based on 14% moisture content. *Control: commercially chlorinated flour, SOFTASILK, TM. General Mills. Minneapolis, MN. Means with the same letter are not significantly

6 ~~ ~~~ 338 F.D. CONFORTI and J.M. JOHNSON Chlorination caused a decrease in the ph of the flour (Table 3.) to such an extent that significant differences existed between the unchlorinated and chlorinated flours. The reaction occurring during chlorination was expressed by Gough ef d. (1978): The authors theorized that flour having a moisture content of % will readily dissolve chlorine, and produce the given reaction. The presence of the hydrogen ion explains the marked drop in ph due to chlorination. Practical experience has shown that best flour performance is obtained when chlorination yields a ph range of (Pyler 1967). All chlorinated flours in this study were below this suggested range. Pratt (197 1) has suggested that excessive chlorine treatment will produce a mellowing effect on the flour's protein. This effect would be desirable in flours with stronger glutens, but undesirable if the gluten is weak. Yamazaki and Lord (197 1) have also noted that soft wheat flour could be treated with chlorine to a ph of approximately 4.3 when the flour would be used for specific baking purposes. According to the authors, the heavy chlorine treatment causes some protein breakdown, but increases starch viscosity. The increase in starch viscosity can be directly related to the flour's rheological properties. 3. EFFECTS OF CHLORINE TREATMENT ON ph OF COKER 916 FLOUR' #3 #6 #4 #13 #15 CONTROL* 5.5 c 4.1 ef 5.7 ab 4.3 d 5.6 bc 4.2 de II #7 I 5.9 a I 4.2 de I1 'Based on 14% moisture content. 5.8 ab 4.1 ef _--_ 4.2 de 'Control = Sohasilk Cake Flour, TM, General Mills. Minneapolis, MN. Means with like letters indicate no significant difference (pa.05).

7 FARINOGRAM: PREDICTING BAKING QUALITY 339 Rheological Properties of Coker 916 Flour The farinograph acted as a sensing element that measured the dough s resistance to mixing during successive stages of development (Bloksma 1984). Dough resistance is determined by the rheological properties of the dough, which included viscosity. Surface properties of the dough, particularly sticking to the bowl walls and blades, contributed to the resistance measured. The cuve of the farinograph was a reflection of three processes: (a) absorption of water; (b) dough development; and (c) dough breakdown. The farinograph curves represented in Fig. 1 were typical of soft wheat flour: short development time and short stability. The peak time (PT, Table 4) is defined as the time needed for the curve to reach its peak or point of maximum dough consistency. Treatments (TRTS) 3, 6, 4, and 7, which were low in crude protein, also had short peak times in the unchlorinated state with some significant differences (p < 0.05). Treatments 13 and 15, which were higher in crude protein content than the other flours, had longer peak times in the unchlorinated state and were significantly different from TRTS 3, 6, 4, and 7. Shuey (1984b) attributed an increase in PT to gluten development. Chlorination had three effects on the PT: (a) increased the PT (TRTS 6, 4, 7); (b) decreased the PT (TRTS 3, 15); or (c) PT remained the same (TRT 13). Chlorination caused an increase in the absorbance of each flour except for TRTS 3 and 15. It is interesting to note that when the absorbance decreased the peak time also decreased, as was noted for TRTS 3 and 15 (Table 4). Early research (Sollars 1958) has shown that chlorine-treated starch has considerably greater swelling properties. The change would cause a more viscous batter, and at same time, protein would intermesh along with the starch in the dough system. Excessive chlorination, however, would have a negative effect by weakening gluten formation. Shelton and D Appolonia (1985) suggested that starch granules interact specifically with other dough constituents. This interaction may also involve specific proteins that are present on the surface of the wheat starch (Greenwall and Schofield 1986). The increase in starch hydration would require a longer mixing time for starch and protein incorporation. The increased mixing time would weaken the gluten and cause a breakdown in dough formation, which would ultimately affect the stability of the flour. Stability and MTI values (Table 4) for each flour sample were determined from the farinograms. Stability indicated the flour s tolerance to mixing. Mixing tolerance index also indicated the flour s tolerance to mixing and can be directly related to stability. Generally, a flour with a good tolerance to mixing will have a high stability value, but a low MTI value.

8 ~ 340 F.D. CONFORTI and J.M. JOHNSON I c-- - -UNChL ' FIG. 1. FARINOGRAMS OF UNCHLORINATED (UNCHL)AND CHLORINATED (CHL) COKER 916 FLOURS

9 FARINOGRAM: PREDICTING BAKING QUALITY 34 1 TABLE 4. FARINOGRAPH DATA FOR COKER 916 FLOUR' CONTROL' 57.7 k 4.50 a a 70 bcde 'Calculation based on 14% moisture. *Control = Softasilk Cake Flour, TM, General Mills, Minneapolis, MN. Means with the same letter denotes no significant difference (p>o.o5). There were significant differences among the unchlorinated flours for both stability and MTI (Table 4). Generally, stability decreased as nitrogen treatments increased as noted for TRTS 3,4,6, and 7. There was a slight increase in stability when a higher split nitrogen was used (TRTS 13 and 15). The split usage and timing may have had an effect on protein development (Doll 1962). Chlorination caused a decrease in the stability of the experimental flours, which was substantiated in a strong correlation (r = -0.97) with MTI. The control flour, which is commercially chlorinated, had a higher stability time, but also had a high MTI value. Stability of the control flour was significantly different (p c 0.05) when compared to the other flours. Although chlorinated, the flour maintained a high stability value that was not reflected in the MTI value. The decrease in stability caused by chlorination indicated that gluten development was lessened. Peak time values of chlorinated flour correlated significantly with stability and MTI (r = and r = 0.92, respectively). Chlorination had a negative effect on the dough-forming properties in the respective flours. Excessir e chlorination could be detrimental to functionality as noted with TRT

10 342 F.D. CONFORTI and J.M. JOHNSON 13 (Tables 3 and4), which had the lowest ph, lowest stability, and highest MTI after chlorination. Although mixing strength is generally related to an increase in protein content (Tanaka and Tipples 1969), there were weak correlations between crude protein and stability (r = -0.74) and crude protein and MTI (r = 0.78) for chlorinated flours. The differences in mixing strength could be related not only to protein quantity, but to protein quality as well, in order to achieve a stable product. Therefore, interpretation of the evidence has indicated that interrelationship of the data will enhance evaluation. Stability and MTI predicted rheological behavior while PT enhanced interpretation. The combined usage of these values should also help to predict the baking quality of the flour. Cake Baking Results: Volume and Tenderness Angel food cake was used as the medium for testing baking quality of the 12 experimental flours. Soft wheat flour is used in angel food cake as: (a) a binder; (b) as a provider of starch for gelatinization; and (c) a supplement for the egg protein in formulation of the cake structure. All purpose flour causes the cake to shrink and pull away from the sides of the pan during the baking and cooling periods because of the cohesive properties of the gluten (Palmer 1972). Yamazaki and Lord (1971) suggested that soft wheat flour be bleached with chlorine to a ph of approximately 4.3, which is lower than is desirable for cakes. This heavy treatment could be responsible for some protein breakdown, but would increase starch viscosity. This increased starch absorbency would compensate for the lack of gluten formation and would contribute to the framework of the baked angel food cake. Angel food cakes prepared with unchlorinated flour were higher, but had an inferior structural quality when compared to angel food cakes prepared with chlorinated flour. Angel food cakes from unchlorinated flour had open and uneven cells (Fig. 2a), while angel food cakes from chlorinated flour had a finer and more rounded cell structure (Fig. 2b). The improvement in the structure of the chlorinated flour cakes resulted in lower volume due to the close packing of the crumb, but an even contour and less shrinkage in the baked product was the result. The percent crude protein content in chlorinated flour was significantly correlated (r = -0.82) with final cake height (H~c)). Cake volumes correlated significantly to Hqc) (r = 0.96) and percent crude protein (r = -0.91) when chlorinated flour was used. The effect of protein content on height and volume was more pronounced when chlorine was applied to the flour. These results were in agreement with Gaines and Donelson (1985a). Early studies by Montzheimer (1931) and Smith (1932) reported that chlorination increased cake volume. Results (Table 5) of this study found a decrease in

11 FARINOGRAM: PREDICTING BAKING QUALITY 343 TABLE S. BAKING QUALlTY OF COKER 916 FLOUR' TRT 6-UNCHL 'Based on 14% moisture. 'Heights taken when removed from tube pan 'Heights taken after 2 hour removal from tube pan. 'Softasilk Cake Flour, TM, General Mills, Minneapolis, MN. Means with the same letter denotes no significant volume when chlorinated flour was utilized in the formula. Treatment 4 (unchlorinated) produced a high volume cake that was significantly different (p < 0.05) from the other flours. Chlorination caused TRT 4 to produce a cake lower in volume, which was similar (p > 0.05) to TRTS 3 and 6. Chlorination caused TRTS 7 and 15 to produce similar volumes (p > 0.05), while TRT 13 produced a cake lower in volume and was significantly different (p < 0.05) from the other flours. Stability and MTI values helped to focus on the cause for lower volumes when the various flours were used. Stability and MTI values for chlorinated flour correlated with volume at r = 0.69 and r = -0.68, respectively. Treatment 13, which had the weakest stability and MTI values (p < 0.05) among the flours, also produced the lowest cake volume (p < 0.05). The farinogram data did imply that chlorination affected the rheological character of the flour and, therefore, overmixing would have a negative effect on cake volume.

12 344 F.D. CONFORTI and J.M. JOHNSON a. b. FIG. 2. ANGEL FOOD CAKE MADE WITH UNCHLORINATED FLOUR (a) HAD AN OPEN AND UNEVEN CELL STRUCTURE, WHILE EVEN FINER CAKE CELLS (b) ARE PRODUCED WITH CHLORINATED FLOUR Chlorinated flour did produce a cake with a finer and rounder crumb structure. The crumbs were closely packed together (Fig. 2b), and this structure was responsible for a cake lower in volume with less tenderness (Table 5). Frazier et ul. (1974) and Ngo et al. (1985) also found that chlorinated flour produced a strong cake crumb with less tenderness. High protein levels in soft wheat flour usually affect tenderness of the product (Matz 1960; Gaines and Donelson 1985b). Protein was significantly correlated (r = 0.95) to tenderness only in cakes from unchlorinated flour. When chlorinated flour was used, values for tenderness followed in a series of similar values except for TRTS 4 and 7, which were similar to the commercial flour. When chlorinated flour was used, the protein s effect on tenderness was clouded, which suggested that other factors may also influence tenderness in an angle food cake. Chlorination caused an increase in the flour s absorbency (Table 4) except for TRTS 3 and 15 in which a decrease was noted. A higher absorbency rate indicated that chlorination was responsible for increasing permeability on the surface of the starch granule. The increased hydration capacity would allow the starch to attract more water during the baking process, which is important in high ratio cake formulas where sugar is also a principal competitor for water. The improved hydration capacity would also be responsible for a complete intermeshing of the starch and protein whereby a firm and stable crumb structure would result. Chlorinated flours exhibited an increase in PT values (Table 4) except for TRTS 3 and 15 in which a decrease was noted and TRT 13 remained unchanged. Peak time was previously cited as an indicator to gluten development, and the increase in mixing time might indicate a more complete intermeshing of starch and protein for gluten development. The correlation coefficient (r = 0.84) between PT and tenderness was significant for cakes produced from chlorinated flour. An

13 FARINOGRAM: PREDICTING BAKING QUALITY 345 increase in mixing time would result in a less tender and low volume product because of excessive gluten development. Farinogram data aided in explaining the baking quality of the flours. Absorbency and PT values were instrumental in assessing tenderness, while stability and MTI values also enhanced the interpretation of baking results. Information derived from the data was in agreement with other studies in which chlorination was responsible for: (a) a stronger crumb (Hoseney et al. 1988) and (b) a more stable and contoured baked product (Seguchi and Matsuki 1977; Seguchi 1984). SUMMARY Chlorination improved the baking quality of soft wheat flour. Less shrinkage and a firm, round crumb resulted when chlorinated flour was utilized in the formula. Data derived from the farinogram were useful for interpreting baking results. The majority of flours experienced an increase in absorbency when chlorination was used. An increase in absorbency and improved starch hydration were responsible for a stable structure in the final baked product. Stability, MTI, and PT values were used jointly to interpret baking quality results. REFERENCES AACC Approved Methods of the AACC. American Association of Cereal Chemists, St. Paul, MN. ASH, D.J. and COLMEY, J.C The role of ph in cake baking. Baker s Dig. 47(1), 3642, 68. BLOKSMA, A.H Rheological aspects of structural changes during baking. In The Farinograph Handbook, (B.L. D Appolonia and W.H. Kunerth, eds.) pp. 7-12, American Association of Cereal Chemists, St. Paul, MN. DOLL, E.C Effects of fall-applied nitrogen fertilizer and winter rainfall on yield of wheat. Agron. J. 5, ECK, H.V Winter response to nitrogen and irrigation. Agron. J. 80, FAUBION, J. and FARIDI, H Dough rheology: its benefits to cereal chemists. In Fundamentals of Dough Rheology, (H. Faridi and J. Faubion, eds.) pp. 1-9, The American Association of Cereal Chemists, St. Paul, MN. FORTMANN, K.L. and JOINER, R.R Wheat pigments and flour color. In Wheat Chemistry and Technology, (Y. Pomeranz, ed.), pp , American Association of Cereal Chemists, St. Paul, MN.

14 346 F.D. CONFORTI and J.M. JOHNSON FRAZIER, P.J., BRIMBLECOMBE, F.A. and DANIELS, N.W.R Rheological testing of high ratio cake flours. Chem. Ind GAINES, C.S. and DONELSON, J.R. 1985a. Influence of certain flour quality parameters and postmilling treatments on size of angel food and high-ratio white layer cakes. Cereal Chem. 62, GAINES, C.S. and DONELSON, J.R. 1985b. Effect of artificially varying flour protein content on angel food and high-ratio white layer cake size and tenderness. Cereal Chem. 62, GOUGH, B.M., WHITEHOUSE, M.E. and GREENWOOD, C.T The role and function of chlorine in the preparation of high ratio cake flour. CRS Rev. Food Sci. Nutr. 10, GREENWALL, P. and SCHOFIELD, J.D A starch granule protein associated with endosperm softness in wheat. Cereal Chem. 63, HOSENEY, R.C., WADE, P. and FINLEY, J.W Soft wheat products. In Wheat Chemistry and Technology, (Y. Pomeranz, ed.) pp , American Association of Cereal Chemists, Minneapolis, MN. MATZ, S.A Formulating and processing chemically leavened goods. In Bakery Technology and Engineering, Chap. 10, Van Nostrand Reinhold/AVI, New York. MONTZHEIMER, J. W A study of methods for testing cake flour. Cereal Chem. 8, NGO, W., HOSENEY, R.C. and MOORE, W.R Dynamic rheological properties of cake batters made from chlorine-treated and untreated flour. J. Food Sci. 50, PALMER, H.H Eggs. In Food Theory and Applications, (P.C. Paul and H.H. Palmer, eds.) pp , John Wiley & Sons, New York. PRATT, D.B Criteria of flour quality. In Wheat Chemistry and Technology, (Y. Pomeranz, ed.) pp , American Association of Cereal Chemists, St. Paul, MN. PRESTON, K.R. and KILBORN, R.H Dough rheology and the farinograph. In The Farinograph Handbook (B.L. D Appolonia and W.H. Kunerth, eds.) pp , American Association of Cereal Chemists, St. Paul, MN. PYLER, E.J Elements of flour performance. Baker s Dig. 41, SAS SAS User s Guide; Statistics. SAS Institute, Cary, NC. SEGUCHI, M Oil binding capacity of prime starch from chlorinated wheat flour. Cereal Chem. 61, SEGUCHI, M. and MATSUKI, J Studies on pan-cake baking. I. Effect of chlorination of flour on pan-cake qualities. Cereal Chem. 54, SHELTON, D.R. and D APPOLONIA, B.L Carbohydrate functionality in the baking process. Cereal Foods World 30,

15 FARINOGRAM: PREDICTING BAKING QUALITY 347 SHUEY, W.C. 1984a. The farinograph. In The Farinogruph Handbook, (B.D. D Appolonia and W.H. Kunerth, eds.) pp. 1-6, The American Association of Cereal Chemists, St. Paul, MN. SHUEY, W.C. 1984b. Interpretation of the fannogram. In The Farinogruph Hundbook, (B.L. D Appolonia and W.H. Kunerth, eds.) pp , The American Association of Cereal Chemists, St. Paul, MN. SMITH, E.E Report of the subcommittee on hydrogen-ion concentration with special reference to the effect of flour bleach. Cereal Chem. 9, SOLLARS, W.F Cake and cookie flour fractions affected by chlorine bleaching. Cereal Chem. 35, TANAKA, K. and TIPPLES, K.H Relation between farinograph mixing requirements. Cereal Sci. Today 14, TERMAN, G.L Yields and protein content of wheat grain as affected by cultivar, nitrogen, and environmental growth factors. Agron. J. 71, TERMAN, G.L., RAMIG, R.E., DREIER, A.F. and OLSON, R.A Yield protein relationship in wheat grain, as affected by nitrogen and water. Agron. J. 61, TSEN, C.C. and KULP, K Effects of chlorine on flour proteins, dough properties, and cake quality. Cereal Chem. 48, YAMAZAKI, W.T. and LORD, D.D Soft wheat products. In Wheat Chemistry and Technology, (Y. Pomeranz, ed.) pp , American Association of Cereal Chemists, St. Paul, MN. ZADOKS, J.C., CHANG, T.T. and KONZAK, C.F A decimal code for the growth stages of cereals. Weed Res. 14,