.\ 2. vii; I‘Il‘. 3.0!}.1! .3 £1.33: .‘V ... .2: ,7 .99 .r 'E‘Al‘ In . .ullutuv.i 70"‘YDII II: 5.11110.th| . ‘ 7!“: x‘ 3-! 1L .1: .93.? In! . "1.5 .5 {#3 v1, ‘1. .a. 91‘ 6.1.. .. ‘ . . y . . Elba... c3539.?! 11 r. . ...|...10.90.. .‘, ... ny‘ 5.300.. A.) ‘ . .,J.%..; I; in. .1 . . . > . . .I .... I .7. n}: -- :Hm’ SlTY U IBRARIES milllllllulu \ll“\\\\\\l\\l This is to certify that the thesis entitled EVALUATION OF TOFU FROM SELECTED SOY CULTIVARS AND BREEDING LINES presented by Hui Wang has been accepted towards fulfillment of the requirements for M.S. degree in FOOd SCiEfiCE fl/Mlflgc Major professor Date March 19, 1993 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution LIBRARY Michigan State University PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or betore date due. DATE DUE DATE DUE DATE DUE lL__ C: V—l ___J I 4:: LA: I II MSU Is An Affirmdive Action/Equal Opportunity Institution email-9' EVALUATION OF TOFU FROM SELECTED SOY CULTIVARS AND BREEDING LINES BY Hui Wang A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Food Science and Human Nutrition 1993 ABSTRACT EVALUATION OF TOFU FROM SELECTED SOY CULTIVARS AND BREEDING LINES BY Hui Wang Soybean tofu made from selected soybean entries and dry bean curd made from dry beans and soybean - dry bean mixtures were evaluated in series of three studies. Twenty six soybean entries produced in two locations during two sequential crop seasons were initially investigated for tofu production (Study I). Soybean entries showed significant differences in fresh yield, textural properties of tofu produced. Tofu made from ten soybean [entries were selected for quality evaluation in Study II. Significant differences were observed in physical, chemical and sensory characteristics of tofu produced. In study III, dry bean and four mixtures of dry bean with soybean were evaluated for suitability for production of bean curds similar to tofu. The results indicated that bean curd could be made with soybean - dry bean combinations. The sensory data indicated that the bean curd made with soybean - dry bean mixtures were less acceptable compared to tofu. ACKNOILEDGKENTB I would like to express my deepest gratitude to my advisor Dr. Mark Uebersax for his endless guidance, encouragement and valuable advice during my graduate study. Grateful acknowledgement is also extended to members of committee Drs. J. Cash, D. Isleib, M. Zabik for their guidance, comments and suggestions through my graduate program. Appreciation is expressed to Drs. T. Isleib, C. Sneller, S. Wittwer, M. Uebersax and Institute of International Agriculture for providing me the financial support. Thanks are also given to the group members in 128 lab at MSU for their help in my study. Special thanks goes to my parents for providing me opportunities to grow and learnt for their love, patience, unending encouragement and support during my study. I would also like to thank my husband.Guilin for everything. This work could not be done without his help. TABLE OF CONTENTS LIST OF TABLES ... .................. ... ..... .............vii LIST OF FIGURES.............. ..... .........................x INTRODUCTION ............ .......... ........................1 REVIEWOF LITERATURE ..................... ....... ..........5 Composition of soybean ...............................5 Nutritional Quality of Tofu ..........................8 Raw materials for tofu production . ...... ............l3 SOYbeanoooooooooooo ...... O ..... 00.000.000.00000013 Other bean sources . ........ ....................14 Tofu processing procedures ..........................15 Preparation of soybean milk . ........... ........16 water:bean ratio 0 O O O O O O O O O 0 O O ...... O O O O O O O 16 heat treatment of soybean milk ............17 Concentration and type of coagulant ..... ..... ..17 Textural properties of tofu ..... ........... .........19 Physical and chemical factors ............. .....19 Microstructure ........... ................... ...21 Instrumental measurements ...................... 23 Shelf life of tofu ...... ...... .................... ..24 Sensory Analysis . ..... . ....................... . ..... 26 MATERIALS AND METHODS ...... . .................... .........28 Source of soybean ................................. ..28 Experiment outline ......................... .........28 Preparation of tofu ......... . .................... ...28 iv Quality evaluation ..................................32 Physical analysis ...... ........ ..... ...........32 Chemical analysis ...... ........................35 sensory evaluation ......OOOOOOOOOOO0.0.0000000038 Statistical analysis .................. ........ ......41 EXPERIMENTAL 0......OOOO.......OOOOOOOOOOOOOOOOO0.00.00.0043 STUDY I. STUDY II. Study III. Evaluation of tofu made from 26 soybean cultivars and breeding lines . ............... ..43 Hypothesis ....................... ........... ..43 Objectives ..... ........... ....... .. ........... 43 Methodology ...... ........... .................. 43 Results and Discussion .......................44 Conclusion ......................... ........... 61 Quality assessment of tofu made from 10 selected soybean cultivars and breeding Hypothesis .................................... 62 Objectives .............................. ...... 62 Methodology ..................... ............ ..62 Results and Discussion .......................63 Conclusion ....................................92 Evaluation of bean curd made from soybean -dry bean combinations .............. .......... 95 Hypothesis ........ . ...... .....................95 Objectives ....................................95 Methodology ............ . ...................... 95 V Results and Discussion ........................95 Conclusion ...................................109 SUMMARY AND CONCLUSION............... ......... ...........114 FURTHER RESEARCH.........................................116 LIST OF REFERENCES 00000000000000 ......0.0.0.0000000000000117 vi LIST OF TABLES Tables. 1. Tofu industry intheUnitedStates......................3 2. Proximate composition of soybeans and seed parts.OO....O.............OOOOOOICOOOOOOOO0.0.06 3 . Nutritional value of soybean and selected foods. . . . . . . . . 7 4. Orientalsoybeanfoods..................................9 5. Composition of tofu as related to level of water content..........................................10 6. Amount of essential amino acids and their percentages of Minimum Daily Requirements(MDR) in 100 gramportionof Japanesetofu...................12 7. Characteristics of 26 soybeans listed in priority as perceived for overall commercial acceptabilitYOOO0.000.0......OOOOCOOCOOOOOOO0......0.0.29 8. Mean value of protein, oil and seed size of soybean from 1990,1991.................................45 9. Analysis of variance for protein, oil and seed size of soybean from 1990 crop year...............47 10. Analysis of variance for protein, oil and seed size of soybean from 1991 crop year...............48 11. Analysis of variance for protein, oil and seed size of soybean from 1990,1991 crop year. . . . . . . . . .49 12. Mean values of yield and textural properties of 1990and1991t0fu00OO......OOOOOOOOOOOOOOOOO0.0...0.0.55 13. Analysis of variance for yield and texture of 1990 tOquOOOOOO0.0.00.......COCCCOOOOOOOIOOOOO0.0.000057 14. Analysis of variance for yield andtextureof1991tofu........................ ...... .58 15. Analysis of variance for yield and texture Oflggoand1991tOfu.......OOOOOOOOOOOOOOOO..........059 16. Regression analyses and correlation coefficients between parameter of soybean and tofu. . . . . . . . . . . . . . . . . . 60 vii 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. Mean values for yield, hardness and color Of 1990 tOquOOO ...... ....OOOOOOOOOOI......OOOOOOOO0.0.64 Mean values for yield, hardness and color °f1991t0fu00000000000 ...... 0....0.00.00.00.000000000065 Analysis of variance for yield, hardness andCOIOrOf1990tOfueoeeeeeeeeoeeoeeeeeeeoeeeeeeeeeeoéé Analysis of variance for yield, hardness andcolorof1991tofu.................................67 Analysis of variance for color, yield andhardness of 1990 and 1991 tofu.....................68 Mean valuezfor sensory analysis of tofu................74 Analysis of variance for sensory evaluation Of1990tOquOOOOOO0.000.000.0000...0.00.00.00.0000000075 Analysis of variance for sensory evaluation Of1991tOfu...0.0.0000.........OOOOOOOOO OOOOOOOOOOOOOO 76 Analysis of variance for sensory evaluation Of 1990 and 1991 tOfu 0000000000 O O O O O ......... O O O ..... O .77 Mean values for proximate analysis of 1990 tofu........81 Mean value for proximate analysis of 1992 tofu.........82 Range of tofu chemical compositions in two crop seasons .............. .... ......................... 83 Analysis of variance for chemical analysis of 1990 sample ........................................ .85 Analysis of variance for chemical analysis of 1991 sample....................... ...... . ........... 86 Analysis of variance for chemical analysis of 1990 and 1991 sample........ ...... . ............... ..87 Mean value of Ca and P of 1990 soybean and tOquOOOOOOOOO.....OOOOOOOOOOOOO. ......... C 000000000000 90 Analysis of variance for mineral content of 1990 soybean and tofu............ .......... . ........ 91 Correlation coefficient between soybean soybean milk and tofu .................................. 93 viii 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. Mean value for yield, texture and color of bean curd made from soybean (SB) and navybean(NB)combination.............................97 Mean value for yield, texture and color of bean curd made from soybean (SB) and Garbanzo bean (GB) combination. 0 O O O O O O O O O O I O O ....... O O .98 Analysis of variance for yield, hardness and color of bean curd made from soybean andnavybeancombination.................. ........... .99 Analysis of variance for yield, hardness and color of bean curd made from soybean and Garbanzo combination..................... ......... 100 Mean value for sensory analysis of bean curd made from soybean (SB) andnavybean (NB) combination........................103 Mean value for sensory evaluation of bean curd made from soybean (SB) and Garbanzo bean (GB) combination. . . . . . . . . . . . . ........... 104 Analysis of variance for sensory evaluation of bean curd made from soybean and navy bean Combination. ........ O...OOOOOOOOOOOOOOOOOOOOOOO00....0105 Analysis of variance for sensory evaluation of bean curd made from soybean and Garbanzo combinationOO ..... .0.........O...’.............. ...... 106 Mean value for proximate analysis of bean curd made from soybean (SB) and naVYbean(NB) combinationo.......OOOOOOO0.0.00.00....107 Mean value for proximate analysis of bean curd made from soybean (SB) and Garbanzo bean (GB) combination. . . . . . . . . . . . . . . ........ . 108 Analysis of variance for chemical analysis of bean curd made from soybean and navy bean combination.OOOO......OOOOOOOOOOOOOOOO0.0...O....110 Analysis of variance for chemical analysis of bean curd made from soybean and Garbanzo combination ............ ......OOOOOOOOOOOOOOOOO 00000000 111 ix LIST OF FIGURES Figures. 1. Experimental outline used to assess tofu quality made of soybean and soybean/dry bean mixtures. . . . . . . . . . 30 2 . Flow chart for preparation of tofu ...... . . . . . . . . ..... . . 31 3. Apparatus fortofu formation...........................33 4. 5. 6. 10. 11. 12. 13. 14. 15. 16. Quality evaluation of soybean and tofu. . . . . . . . . . . . . . . . . 34 The TPA-1 cell used in texture profile analysis (TPA test) ;from Food Technology Co. , Maryland. . . . . . . . . . 39 Typical TPA curve for objective evaluation of food texture (from manual of TMS-90 Texture Press, Food Technology Co., Maryland) ..................... ... ...... 40 Quality characteristics and hedonic scale terminology used for tofu evaluation ................... 42 Mean values of protein and oil content of soybean from 2 locations over 26 entries during 1990 crop season... ..................................... .... ..... 50 Mean values of protein and oil content of soybean of‘2 crop seasons over 2 locations and 26 entries......51 Inverse relationship between protein and oil in soybean during two crop seasons ........... . . . . . ...... . . 53 Mean values of tofu color for 2 years over 2 locations and 10 soybean entries ................. . . . . . . 69 Mean values of tofu color from 10 soybean entries overzlocationsandzyearSOOOOOOO......OOOOOO...0.0007O Mean values of fresh tofu yield and hardness for 2 years over 2 locations and 10 soybean entries. . . . . . . . . . 72 Mean values of tofu yield from 10 soybean entries overz locationsandZyears.. ......... ................73 Mean values of sensory evaluation for 2 years over 2 locations and 10 soybean entries. . . . . ...... . . . . ...... 79 Mean values of sensory evaluation from 10 soybean entries over 2 years and 2 locations ................... 80 17. 18. 19. 20. 21. 22. Mean values of proximate analyses for 2 years over 2 locations and 10 soybean entries........ .. . .. . .88 Mean values for chemical anaylyses of tofu from 10 soybean entries over two years and 2 locations. . . . . . . . . 89 Yield and hardness of bean curd made from different soybean and navy bean combinations. . . . . . . . . . 101 Yield and hardness of bean curd made from different soybean and Garbanzo combinations. . . . . . . . . . . 102 Total solids of bean milk, fat, ash, and fiber content of bean curd made from different soybean andnavybeancombinations............................112 Total solids of bean milk, fat, ash, and fiber content of bean curd made from different soybean and Garbanzo combinations.... ...... ...... ............. 113 xi INTRODUCTION In recent years, people have paid more attention to plant protein foods due to a greater concern for decreasing total fat and cholesterol in food and diet. A large number of low technology soybean foods that have been an important protein source in the far eastern countries for centuries have appeared on market outside the Oriental community. Tofu, an economical dietary source of high quality, cholesterol- free protein, has attracted much attention in western countries because of its overall nutritional quality. Tofu is an important nonfermented soybean product that is used widely by Oriental people. It has the same importance to the people of the Orient that meats, eggs and cheese posses for the people in western countries. It is a highly hydrated , gelatinous product with a soft , smooth texture and possesses a bland taste (Wang et a1 1984). Tofu can be readily incorporated with other foodstuffs and used in nearly every culinary context, from salads to desserts and from breakfast to burgers. The tofu Market Survey (Lim, 1984) showed that 33% of Americans had heard of tofu, 18% had tasted it, and 10% had purchased it. Americans consumed 2.13 pounds of slightly processed soyfoods per year per capita. Per capita tofu consumption approximates the annual consumption of yogurt at 2.7 pounds (Lim, 1984). Soyfood industry observers have spoken of tofu becoming the "yogurt of the 19805" (Lim, 1984). According to information published by the Soyfoods Center of California, 1 2 the number of tofu producers in North America rose from 50 in 1975 to 182 in 1983, and annual production has increased from 13,250 tons in 1979 to 27,500 tons in 1983 (Table 1). The growth trend is expected to continue to increase in the immediate future. Tofu is generally made from a filtered water extract of whole soybeans called soymilk. The curd is obtained by coagulation of hot soymilk with a coagulant, followed by molding and pressing to remove whey (Lim,1990). For centuries the processing of making tofu.has been controlled by tradition and experience; without the benefit of scientific knowledge, tofu "craftsmen" have skillfully carried on the process (Wang et a1., 1983). In recent years, several studies have been made on tofu processing in an attempt to better understand the process and to optimize the processing conditions. It has been commonly’ recognized. that soybean. variety' has significant differences in fresh yield of tofu. Soybeans with large uniform size, light hilum and. high. protein content are preferred for the production of tofu. Therefore, a potential exists in selecting the most suitable variety of soybeans for making tofu. This investigation dealt with evaluation of tofu produced from 26 soybean cultivars and.breeding lines grown in Michigan during the 1990 and 1991 crop years. The objective of this study is to investigate the characteristics of soybean that affect the yield and quality of tofu. Further, selected dry beans (Garbanzo and Navy bean) mannaflm>m uoz u «z . 3 Amcouc oom.h~ con.e~ ooH.Hm mnm.ma om~.na .cz :ofluoaeouo Hmscc< «ma mus mma mefl oNH om memosooud no .02 name mama Hams coma mnma meme MOON .wmma .mcozv moumum couwca may :a huumsocw suoa .H manna 4 were evaluated for their production potential as bean curd in order to promote the use of dry beans in processed foods. REVIEW OF LITERATURE Composition of Soybean ( Glycine max (L.) Merr.) Soybean is one of the most important cash crops in the United States. They contribute more protein and fat to our food economy than any other single source ( Liener, 1978 ). Soybean is a useful source of both water- and fat-soluble vitamins including thiamin, nicotinic acid and pantothenic acid ( Moinichen, 1952 ). On a moisture free basis, the average composition of whole soybean seeds is 40.4% protein, 22.3% fat, 31.9% nitrogen free extract plus fiber, and 4.9% ash (Horan, 1974). The proximate composition of soybeans and various seed parts and a comparison of soybean with other selected foods are shown in Tables 2 and 3, respectively. Soybean protein is unique among plant proteins because of its relative high biological value ( Schroder et al., 1973 ). The amino acid distribution of soybean protein is similar to that recommended by the Food and Agricultural Organization (FAO) of the United Nations. In general, protein of animal origin ranks highest and plant protein ranks lowest when their total essential amino acid content is expressed as a fraction of total nitrogen. However, soybean protein assumes an intermediate position ( Liener, 1978 ). On the basis of essential amino acid composition, the sulfur-containing amino acids limit the nutritional value of soybean protein (Liener, 1972). However, soybean protein is higher in lysine than most other plant proteins (Lim, 1984) . Soybean has been used to Table 2. Proximate Composition of Soybeans and Seed Parts. Protein, Fat, Carbohydrate, Ash, (N x 6.25) Fraction % % % % Whole bean 40.0 21 34 4.9 Cotyledon 43.0 23 29 5.0 Hull 8.8 1 86 4.3 Hypocotyl 41.0 11 43 4.4 *Moisture-free basis (Wolf, 1977) Table 3. Nutritional Value of Soybean and Selected Foods1 (g/IOOg food) Consistuent Soybean beef milk moisture protein fat CHO fiber ash Ca(m9) Ptmgi Fe(mg) 10.2 36.3 18.4 25.3 4.8 5.0 367.0 571.0 11.0 Nfl 0 O O N U ummHOHmoo NOOHOQNUQ on OUOOOU'IbUQ 0.0.0.... NOOQOOOUO ... lON (China Food Composition Table, 8 produce a wide variety of foods in the Oriental diet. Based on processing technology, the soybean foods can be classified into two general types: non-fermented and fermented as shown in Table 4. Names of these foods and details of preparing and serving such food may vary by regional and cultural tradition. Among these foods, tofu has been the most widely consumed throughout the Orient. Soybean based foods offer an excellent source of protein and have a relatively low price, therefore, they are becoming more popular in western countries. Tofu has been the most widely accepted soybean food by the western people (Wang, 1986). Nutritional Quality of Tofu Tofu has been used as a protein source in the Orient for many centuries. It is high in lysine and only moderately low in methionine. It is also an inexpensive protein source for human food as compared to animal sources such as pork and beef (Wu et al., 1983). Many kinds of tofu are produced in the Orient. Depending on the type and concentration of coagulant used as well as extent of stirring during coagulation and subsequent pressure applied to the curd, tofu ranges in hardness from "soft" to "firm" with a moisture content ranging from 70 to 90% and protein content ranging from 5 to 16% ( Deman et al., 1986 ). The method of preparation greatly affects the water content of the final product, it also influences the percentage of other components (Table 5) . Tofu as produced in United States 9 Table 4. Oriental Soybean Foods Foods Description and Uses HQDEEIEEDLEQ Soybean sprouts Soybean milk Protein-lipid film Soybean curd (tofu) EQIEQBEQQ Soy sauce Miso Tempeh Natto Bright yellow beans with 3-5 cm sprouts. Cooked and served as vegetable or in salads. Water extract of soybeans, resembling'dairy'milk. Served as a breakfast drink. Cream—yellow film formed over the surface of simmering soybean milk. Cooked and used as a meat substitute. White or pale yellow curd cubes coagulated from soybean milk. Served as main dish with or without further cooking. Dark reddish brown liquid, salty taste suggested the quality of meat.extract, a flavoring agent. Paste, smooth or chunky, light yellow to dark reddish brown, salty and strongly flavored resembling soy sauce, used as a flavoring agent. Cooked soft beans bound together by mycelium as a cake, clean fresh and yeasty odor. Cooked and served as main dish or snack. Cooked beans bound together by and covered with viscous , sticky polymers produced by bacteria, ammonium odor, musty flavor, served with or without further cooking as main dish or as a snack. (Wang, 1986) 10 16mm” .mcmzc n.a m.~ m.n 6.6 o.mm noon m.a ~.n ~.v m.> H.mm endows m.H ~.n ~.e m.n w.¢m 30H ofiumu » w w » :uou Hanna Hwo\Cwououm mpfiaom Hao swououm Munoz :fi Loans No umnuo Hm>mH m>numamm acoucou pogo: mo Ho>ma ou coumHou mm :uou uo sawuflmomfioo .m manna 11 markets usually contains 75-80% water. According to united States tofu producers, western consumers prefer tofu with a firm, chewy texture ( Wang et al., 1983 ). Other nutrients typically present in 1009 tofu with 84.8% of water include: fiber, 0.1g; calcium, 128mg; phosphorus, 126mg; iron, 1.9mg; sodium, 7mg; potassium, 42mg; thiamin, 0.06mg; ribaflavin, 0.03mg; niacin, 0.1mg (Wang, 1986) In a study by Muto et a1. (1963), tofu was judged to be nutritionally equivalent to the protein derived from a mixture of eggs, fish and liver. A 100g serving of Japanese tofu contains 7.8% protein, most of the essential amino acids accounts for over fifty percent of Minimum Daily Requirements (MDR) of amino acids (Table 6). Tofu is low in calories and saturated fats and entirely free of cholesterol. A. typical. 8-ounce ( 2279) serving contains only 147 calories. Generally, 80% of the fatty acids tofu contained are polyunsaturated and 15% are saturated fatty acids. Tofu is relatively high in linoleic acid, one of the most important unsaturated fatty acids. By comparison, beef fat is high in saturated fats (48%), low in unsaturated fats (47%) and contains only 9% linoleic acid (Shurtleff and Aoyagi, 1983). Because of its low carbohydrate content (approximately 5 grams in 8 ounces of tofu), it can be used for a supplement to starch-restricted diets (Shurtleff and Aoyagi, 1983). Tofu offers an excellent source of calcium. The Ca/P ratio in tofu is more favorable than that obtained in Table 6. 12 Amount of essential amino acids and their percentages of Minimum Daily Requirements(MDR) in loo-gram portion of Japanese tofu Amino Acids* MDR "Tofu MDR (9) (9) (*i Tryptophan 0.25 0.12 47 Methionine 0.20 0.10 52 Leucine 1.10 0.59 52 Valine 0.80 0.43 53 Isoleucine 0.70 0.41 59 (Phenylalanine- tyrosine) 1.10 0.75 67 Lysine 0.80 0.57 71 Threonine 0.50 0.37 72 Phenylalanine 0.30 0.48 160 *Amino acids in shortest supply are listed first. Those in parentheses are important combinations of essential and non-essential amino acids with common properties. (Shurtleff and Aoyagi, 1983) 13 meat, poultry and other phosphorus-containing protein sources (Bowes and Church, 1975). For individuals who are allergic to milk.products or are intolerant to lactose, tofu is a possible substitute (Tseng et al., 1977). Raw Material for Tofu Production 0 ea Soybean remains the principle starting material of tofu processing. The variety of soybean used.may affect thezquality of tofu and this is considered to be due to differences in protein content of soybeans and the ratio of 7S and 118 proteins (Skurray et a1, 1980). Snyder and Kwon (1987) reported that soybeans that had large uniform size, light colored hilum, thin seed coat and high protein were preferred for soymilk and tofu production. Watanabe et a1. (1960) suggested Japanese soybean varieties were more desirable for making tofu than U.S. soybeans. But Smith et al (1960) reported that the most important difference between Japanese and U.S. soybeans, as viewed by' Japanese customers, were in resultant. product texture and color of prepared tofu . Although composition and yield of tofu varied with soybean variety, the average yield and firmness from U.S. soybeans was the same as that obtained from Japanese beans. Wang et al. (1983) studied the effect on the yield of tofu of five U.S. and five Japanese soybean varieties grown under the same environmental conditions. These researchers 14 found that tofu prepared from different soybean varieties showed significant differences in fresh yield. However, they reported no significant correlation between the protein content of the soybeans and yield of tofu. Tofu made from a soybean variety with a high protein content has a higher protein/oil ratio than tofu made from a soybean variety with less protein. Varietal differences affected the composition and color of tofu. Varieties that had a light hilum and high protein content are preferred. Lim et al. (1990) studied the characteristics of soybeans and soymilk that affect the yield.and.quality of tofu using nine light.hilum.soybean varieties. They found.the yield of tofu was not affected by the size of soybeans. Soybean varieties high in protein, fat and phosphorus contents produced tofu with higher protein, fat and phosphorus contents. Two models for predicting the yield of tofu were proposed. According to model one, soymilk with higher pH and total solids gives a higher yield of tofu. According to model two, soybeans high in protein and ash and low in phosphorus give a higher yield of tofu. W Legumes such as faba beans, winged beans and field peas have been investigated as possible alternatives to soybeans in the production of high protein curd. Studies by Zee et al. (1988) indicated that a process for making traditional soybean tofu (SBT) could be modified to produce a tofu-like curd from 15 faba beans. Faba bean tofu (FBT) had a higher protein content and lower lipid content on a dry basis than did traditional SBT. FBT was comparable to SBT in terms of in vitro digestibility and amino acid availability. Antinutritional factors such as tannins, trypsin inhibitors and flatulence factors (stachyose and raffinose) were reduced in FBT compared to SBT. Kantha et al. (1983) prepared.winged.bean curd using 100% winged bean and five ratios of winged bean-soybean mixtures. They indicated. that. 50:50 and .25:75 winged. bean-soybean combinations resulted in satisfactory products. Their studies also showed that winged bean curd had very low hardness values compared to soybean tofu. They attributed these lower hardness values to be caused by an absence of 118 protein fraction in the winged bean protein. Gebre (1983) studied field peas used to produce a curd similar to tofu but with a higher protein and a lower oil content. Flavor of the field pea curd and soybean tofu was rated similar, but the texture and color of the field.pea curd was scored lower. Amino acid composition of the field pea curd compared quite closely to that of soybean tofu. The addition of gluten ( 4% ) improved the color and texture of field pea curd and also improved the sulfur amino acid profile. Tofu Processing Procedures Typically, three main steps are involved in making tofu: 1) preparation of soybean milk, 2) coagulation of protein and 16 3) formation of tofu in a mold. Normally the process is initiated with dry beans which are soaked overnight until fully hydrated. The soaked beans are rinsed, drained and ground with water. The resultant slurry is filtered through cheesecloth yielding a milk-like product called soybean milk. This soybean milk is heated to a boil. When coagulant is added to the soybean milk, protein precipitates and the curd forms. Then the curd is pressed to remove excess whey, thereby forming the final product -- tofu. Sometimes even though tofu is made with same procedure and same instrument, the production of a consistently high-quality and reproducible product is a problem. Studies have been conducted to evaluate such processing conditions as the suitable bean.to*water ratio when preparing soybean milk, the heat treatment ( time and temperature ) of soy milk, the temperature of coagulation and the concentration.and type of coagulant. All these factors are related to the yield, composition and texture of the final tofu product. It is commonly believed there is a complex interaction of many factors that involved in the tofu processing. Preparation of soybean milk Waterzbean ratio. The most suitable ratio of water to dry beans is between 8:1 to 10:1 according to Watanabe et al. (1967). They reported a significant reduction.in the amount of protein and total solids extracted when the ratio of water to dry bean was reduced to 6.5:1. Increasing the ratio above 17 10:1 increased the amount of solids and protein extracted. Excess water would result in a soybean milk with a protein concentration too low to obtain proper curd formation. Therefore, the ratio of water to dry beans is preferred at approximately 10:1. I Heat treatment of soybean milk. The heat treatment of soybean milk is essential for protein to obtain proper curd formation. The heat treatment improves nutritional value, inactivates enzymes and reduces off-flavor. Tofu is often consumed without further cooking, therefore sufficient heat treatment is necessary to destroy antinutritional factors and to obtain maximum nutritional value of soybean milk. Wang et al. (1982) indicated that the maximum nutritional value of soybean milk could be ensured by boiling the soybean milk for 10-15 min, but.excessive heat treatment.would.adversely affect the nutritional value. Watanabe et al. (1967) reported that boiling the soy milk for more than 20 min not only reduced the total solids recovery and tofu yield, but also adversely affected the tofu texture. Concentration and type of coagulant The addition of coagulant to soybean milk to precipitate the soy protein is the most significant step in the production of tofu (Wang, 1984) . Both the concentration and type of coagulant will signifidantly affect the yield and quality of tofu. The most commonly used salt in soybean curd preparation is calcium sulfate. Tofu prepared from calcium sulfate has a 18 smooth uniform form and elastic texture. Because of the limited solubility of calcium sulfate, the actual concentration at each level may be uncertain , and the concentration gradient may be less than that indicated. This limited solubility may partly account for the smaller variation noted in tofu made with calcium sulfate, compared with tofu made with other salts. Lu et al. (1980) investigated other calcium salts and two noncalcium compounds as coagulants. The results showed that soy protein was precipitated by calcium chloride, calcium lactate, calcium acetate, calcium gluconate, glucono-delta-lactone (GDL) and acetic acid. They recommended that the pH, not the calcium ion, was by far the most important factor in the precipitation of soy protein. They also recommended that it might be advantageous to use either calcium. acetate or calcium chloride as precipitants for soybean curd preparation instead of calcium sulfate, because the amount of both these salts required to precipitate soy protein was less than one-half that required of calcium sulfate. Wang (1984) reported that both ionic concentration and type of coagulant could affect gross weight and moisture content of the final product, as well as total solids and nitrogen recoveries. When calcium sulfate was used, gross weight, moisture content of tofu and total solids recovery decreased as the salt concentration increased from 0.01 to 0.02M, remained about the same between 0.02 to 0.04M, and then l9 steadily increased at higher concentrations. No curd formed when the concentration of coagulant was higher than 0.1 and lower than 0.008M. However, the percentage of nitrogen recovery increased as the concentration of the salt increased, remained the same at 0.02 to 0.04M, and then decreased at the higher concentrations. Wang (1984) indicated the use of salt at a level between 0.02 to 0.04M was more likely to yield a reproducible product with a relatively high nitrogen recovery. Tsai et al.(1981) conducted.a study on.yield and.quality characteristics of tofu using various coagulants at concentrations ranging from 0.01 to 0.08M and reported that based on coagulation and texture, coagulant concentrations between 0.025 to 0.03M were more suitable for making Chinese style tofu. Lu et al. (1980) reported that calcium sulfate concentrations ranging from 0. 1- 0.5% were suitable for soybean curd preparation. Such differences in coagulation concentrations were considered due to the difference in boiling time of the soybean milk. Textural Properties of Tofu Tofu is a gelatinous product with a coherent, smooth and firm texture. These textural properties play an important role which. influences quality’ and. consumer' acceptability. Therefore, texture of tofu has been extensively Studied. W Wang et al. (1983) reported that the hardness of tofu.was found to be negatively correlated to its water content; ie, 20 the hardness of tofu increases as its water content.decreases. Saio (1979) suggested that higher solids in soymilk correlated with harder tofu and increasing coagulating temperature would increase hardness of tofu. Wang and Hesseltine (1982) reported that the temperature of soymilk.and.the:mode of mixing greatly affected the yield and texture of the resulting tofu. When temperature was increased, the gross weight and moisture content of the curd decreased, but its hardness increased. Increased mixing also would decrease tofu volume, therefore increased density and hardness. DeMan et al.(1986) reported that the texture of the curd was greatly influenced by type and concentration of coagulant. They found curd obtained with CaClz.2H20 and MgClz.6HZO was coarse, granular and hard, whereas CaSO‘.1/2H20 and GDL(fresh solution) gave a very smooth, soft and uniform texture. Among the coagulant they used, 0.75% CaSO‘ and 0.4% GDL appeared to be most suitable for making tofu of high bulk weight and smooth texture. In Wang's study (1983) , when the concentration of coagulant was increased from 0.01 to 0.02M, significant increases in hardness, brittleness, cohesiveness and elasticity were found. No significant effect was observed at concentrations between 0.02 to 0.04M, but above this range the firmness measurements of the curds decreased steadily. Saio et al. (1969) found that gel made from 118 protein isolated from defatted meal was much harder than that made from 78 protein. They also noted that the hardness of tofu 21 increased as the amount of phytic acid added to soybean milk increased. Because the 78 to 11$ ratio and phytic acid content of the beans could vary with the variety, they suggested that soybean variety could have an effect on tofu texture. Skurray et al. (1980) compared 15 soybean varieties and found no significant correlation among 78 to 118 ratio, phosphorus content and textural quality of tofu. But they found that the texture of tofu was greatly affected by the amount of calcium ion added. They suggested that the chemical variations among soybeans were not great enough to have a significant effect when compared with processing variables. W The microstructure of tofu as well as physical and chemical factors that regulate its textural properties have been studied extensively. Curd strength is related to the interactions between protein molecules, such as hydrogen bonding, ionic bonding, disulfide bonding and hydrophobic association. Interactions between or within protein molecules determine the microstructure of the protein network. The microstructure integrates into the structural network which is interpreted as mechanical properties during processing and textural properties upon consumption (Lee and Rha, 1978). Saio (1979) studied the structure of soybean curd using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) . This study showed that the density of the network of tofu correlated with hardness of tofu. Density of 22 tofu varies with amount and type of coagulation, phytic acid content, and loss of whey during coagulation. Saio (1979) also showed that large protein aggregates resulted in harder tofu. Because sulfhydryl-disulfide interchange reactions occur predominately in heat aggregation of 11 S, the larger aggregates of 11 S result in a network with a large protein aggregate. Precipitability of 7 S and 11 S with calcium salt differed; ie, 11 S began to precipitate faster than 7 S in lower calcium concentrations and formed a larger aggregate. Formation of the soluble aggregate of 11 S was accelerated in the presence of calcium salt (Saio and Watanabe, 1973). Lee et al. (1983) showed that tofu's deformability mode was regulated by both the solid matrix properties and internal hydrostatic pressure. Lee and.Rha (1978) studied the relation of protein interactions and the, microstructure of soybean protein aggregates to the textural properties of the curd. They found that isoelectric point precipitation and calcium coagulation did not change the globular structure of the native soybean protein. However, heating induced the destruction of the native protein body as protein denaturation was necessary in formation of the structural network of the aggregates. When protein aggregates were frozen, their structures became better defined and enlarged. From heated soybean protein, the three-dimensional network structure of the aggregate showed low sedimention rate, high curd yield, high water-holding capacity, low value of hardness, and high 23 springiness compared to unheated precipitates of globular structure (Lee and Rha, 1978). ns menta measurement The textural properties of various types of tofu were considered major quality attributed in the product. Textural properties of tofu can be evaluated instrumentally using Texturometer or Instron texture profiling analysis (Lee and Rha, 1978; Saio, 1979). Skurray et al. (1980) evaluated the textural properties of tofu using an Instron Universal Testing Machine (Model 1140) to measure hardness and cohesiveness. An important factor affecting the texture of tofu was found to be the amount of calcium ions added. A linear relationship was found between the protein content of beans and the calcium sulfate concentration required for good quality of tofu. Wu and.Peng (1983) studied.the textural properties of soy -cheese whey curd with an Instron Universal Testing Machine. Five parameters were determined: stiffness, bioyield point, firmness, relaxation, and plasticity. When curds were prepared at different soymilk concentrations, stiffness and firmness were affected but other textural parameters were not altered. Therefore, these researchers, believed. that stiffness ‘and firmness best defined the textural parameters for their soy- cheese curd. Lu et al. (1980) used an Instron Universal Model 1132 with a compression fixture attached to determine hardness of 1“ 24 soybean curd. Tsai et al. (1981) studied the textural properties (jelly strength, softness, and chewiness) of tofu by a Rheometer (NRM 2002J, Fu do Kabu shiki Kaishia, Japan) using an adaptor No.3 (0.8) and forcing the plunger 1.5cm.into the sample. Lee et al. (1983) investigated the rheological behavior of tofu by considering its compressive behavior and using three methods: stress vs true strain, stress relaxation, and percentage recoverable work at different strains. The researchers noted that textural studies are dependent on the test. geometry (e.g. the specimen or ;penetrating' plunger dimensions) and the test conditions (especially the arbitrarily selected defamatory level) . For this reason, they cautioned that results published by different authors can not be compared meaningfully or expressed in terms of fundamental mechanical parameters such as module and strength. It is also recognized that in mechanical analyses of many food materials, especially by compressive tests, the accurate determination of fundamental rheological properties is by no means a straight forward. process due. to innate theoretical complications (Peleg 1976, 1977), and frequently imperfect or inappropriate testing conditions (Culioli and Sherman, 1976). Shelf Life of Tofu Tofu is a high quality protein food product; however, it is easily spoiled due to the effect of microbial growth of 25 bacteria. This becomes the major limiting factor in the distribution and marketing of fresh tofu. In recent years, several studies have been made on extending shelf life Of tofu. Pontecorve and Bourne (1978) developed simple methods of preservation in tropical areas without refrigeration. The methods included immersion in aqueous solution, smoking and combination of these two methods. Their studies showed that the shelf life of tofu was successfully extended to 10-15 days without refrigeration by smoking and also by storing in salt brine acidified with lemon juice. Wu and Salunkhe (1977) investigated in-package microwave heating treatment of fresh soybean curds on the shelf life of tofu. They found storage at 4.5°C, soybean curds preheated with microwave to 65°, 80° and 95° had shelf life of 16, 21 and 27 days respectively, compared to 7 days in control. They also found that decreases in pH, increases in titratable acidity and.viable counts.in the soaking water accompanied the decreases in the quality of soybean curds. Although microwave heating treatment for extending shelf life of soybean curds were economically feasible, application to industrial scale requires consideration of limiting factors such as the microwave apparatus and the amount of soybean curd to be treated. Lim (1984) investigated the use of chemical preservatives to extend shelf life of soybean curd and evaluated the effect 26 of the addition of selected chemical preservatives to the immersion solution of soybean curd. The researcher found that the immersion solution.of 0.5% acetic acid.and 0.15% potassium sorbate + 0.5% acetic acid was effective in controlling bacteria growth during 23 days storage period at 10 -- 15°C. Immersion solution of 0.1% citric acid and 0.15% potassium + 0.1% citric acid were effective as antimicrobial agents during 13 days of storage. Nutrient composition of soybean curd in immersion solution. (0.5% acetic acid and 0.15% potassium.sorbate + 0.5% acetic acid) during 21 days storage at 4-7°C were determined by Miskovsky and Stone (1987). The result showed that thiamin and riboflavin in soybean curd decreased during storage, representing leaching of the vitamins into immersion solutions. Decreases in protein and increases in carbohydrate were noticed after 14 days storage. Decreases in proline and arginine occurred following 14 days of storage, but no losses were found in remaining the amino acids. Sensory Analysis Fresh tofu has a characteristic odor, flavor, and mouthfeel. Spoilage of soybean curd is characterized by a sour taste and sometimes an acidic odor. When soybean curds are placed in immersion solutions for preservation, they may acquire the characteristic flavors of the solutions. Pontecorve and Bourne (1978) conducted a sensory study to compare immersion solutions used in preservation of soybean 27 curds. The jpanelists, evaluated flavor, aroma, mouthfeel, texture, color, and general appearance of the samples on the basis of their own individual preferences, indicating at each session which sample was preffered. Samples were presented randomly to equalize the sample sequence effect on food preferences as recommended by Eindhoven et al. (1964). Panelists chose immersion of tofu in a solution of 4% sodium chloride and 10% lemon juice as the best method in the study. Dotson et al. (1977) evaluated the flavor of soybean curd by comparing flavor of the test samples.during the storage period with that of freshly made soybean curd. Results from this trained sensory panel showed.that a decrease in soybean flavor corresponded to microbiological count, pH, and optical density changes observed in the liquids that surrounded the soybean curds. Material and Methods Source of Soybean Twenty six soybean cultivars and breeding lines were randomly‘ cultivated. in. two counties (Ingham and. Lenawee counties). Soybean samples were produced in two crop seasons (1990 and 1991). The experimental design. was randomized complete block.with two replications in each.county. Plot size consisted of two row that were 14 feet long with 30 inch spacing between.rows. Only one replication was received.during 1991 crop season. The harvested seed samples were stored in paper bags at 45°F cooler after receipt. The agromonic and physical characteristics of 26 soybeans were presented in Table 7. Experimental Outline Twenty six soybean cultivars and breeding lines were initially evaluated as a quality screening, subsequently 10 soybean entries were selected for quality evaluation because of their differential characteristics. Cultivar Vinton 81 was selected based on its physical and chemical characteristics and was used in the trials for making tofu in combination with other dry bean sources. The outline for the experiments is presented.in Figure 1. Preparation of Tofu A flow chart for preparation of tofu was presented in Figure 2. 100 grams of soybean were cleaned with tap water, then soaked overnight (16 - 18 hrs.) in 1000m1 distilled water 28 29 Table 7. Characteristics of 26 soybeans listed in priority as perceived for overall commercial acceptability Designation Entry Characteristics and No. plant breeder assessment1 VINTON 81' 14 tofu check (export quality) BEESON*80* 15 tofu check (export quality) E90010 10 large seeds, good yield, good lodging E90006' 6 large seeds, good yield, good lodging NKG SZO-26' 21 good yielding check, yellow hilum, avg. sized seeds CENTURY 84* 19 high protein check with black hilum, good yield E90011 11 Decent looking MSU line, large seeds E90004 4 Decent looking MSU line, large seeds E90001. 1 Decent looking MSU line, largest seeds E90008 8 Decent looking MSU line, large seeds E90007 7 Decent looking MSU line, large seeds ELGIN 87* 18 high yield, low protein,standard MI variety, black hilum GLH GL2291 22 high yield, avg. seed size, yellow hilum E90009 9 average MSU line E90005 4 average MSU line E90012 12 average MSU line E90013 13 average MSU line E90003 3 average MSU line SIBLEY' 16 adapted cultivar, avg seed size, yellow hilum A86-202027 25 Iowa line, prone to lodging M83-504 24 Minnesota line E90002 2 poor agronomic performance and avg seed size PIO 9303 20 too late maturing for most of MI, yellow hilum M82-599 23 consoy 79' 17 small seeds LN85-5382 26 too late maturing for MI 1. Judgement of priority provided by plant breeder Dr. Clay Sneller in Crop and Soil Science MSU. * Designate 10 selections made based on developing a broad array of suitably diverse material to be used for detailed analyses (study II) 30 -——Study I: Evaluation of tofu made from 26 soybean cultivars and breeding lines 26 soybean entries 2 locations (Ingham and Lenawee counties) 2 seasons (1990, 1991) -——Study II: Quality assessment for tofu from 10 selected soybean cultivars and breeding lines 10 soybean entries 2 locations (Ingham and Lenawee counties) 2 seasons (1990, 1991) Study III: Evaluation of bean curd made from soybean (SB) and dry bean (DB) [Garbanzo(G) & Navy bean (N)] combinations as follow: Five Ratios Drx_beani Sexbean ODB(G,N): lOOSB 25DB(G,N): 7sss 500B(G,N): sass 75DB(G,N): zsss IOODB(G,N): 053 Figure 1. Experimental outline used to assess tofu quality made from soybean and soybean/dry bean mixtures Was 31 Soak 100g soybean in water overnight at room temp. Use Acme Supreme Juicerater to blend and macerate beans with soak water .j Soybean milk Heat to boil for 5 mins, then cool to 70 - 80°C Add salt (CaSO‘) at 0.85% level to the soymilk, hold for 15 min. and stir gently for several times. Curd * Transfer to cloth-lined tofu apparatus , drain for 30 minutes Add weight to achieve pressure about 20g/cm2, press for 60 minutes Whey Figure 2. Flow chart for preparation of tofu 32 at room.temperature. The soaked.beans were drained and.blended with soaked water in Acme Juicerator for 5 minutes. The Juicerator has a centrifugal juice extractor, and the residue and soymilk were separated automatically. The extracted soymilk was heated on a hot plate to boil for 5 minutes, then cooled to about 75°C. A suspension of 0.85% CaSO4 in 50ml distilled water was prepared. The hot soymilk and coagulant were poured simultaneously into a 500ml plastic container ensuring mixing without stirring. The curd was left at room temperature to coagulate for 15 minutes, then the curd was stirred about 10 times using a plastic spoon and was transferred to tofu apparatus (Figure 3), finally the weights was added to achieve pressure about ZOgjcmF. The curd was pressed for 60 minutes prior to analyses. Quality Evaluation The outline for quality evaluation of fresh tofu is presented in Figure 4. We 1) Color The color of curd was measured with Hunter Lab Model 025 - PC2 system which includes an optical sensor, a sensor surface unit and.the Zenith.computer. The.colorimeter measures reflectance on three coordinates labeled L( darkness 0 to lightness 100), aL (green - to red + ), and bL (blue - to yellow +). The L, aL and bL values were average of four readings obtained while rotating samples 90° between readings. 33 Weight (3000g) Plastic cylinder (15cm length, 7.6cm diameter) Plexiglass (150 cm sq.) 150m . . TOf’U. . . . . . , , , , 30 mesh sieve with l L___2 layers cheesecloth x5¢22 I‘ll-.o::.- .- . ...... . I. ..... '. .'- fifiefiflfififiwflmfi ,fifi x- 5:2 ' ' . ‘ ' I 3:5 .‘: A‘“v’ 3 :l . ":': I,:‘\-:: “3.5.. 1'“? area ”1... TIME/DISTANCE ~e—- uP-———i-:i7 dawn -e--n— uP-dn- down I l L— FIRST 13m: ’1‘— SECOND BITE —’1 WE FORMULA UNITS HARDNESS value of hardmssl lb or Nev/ton COHESIVENESS area Zlarea 1 - ADHESIVENESS area 3 in-lb or N-cm STRINGINESS distance of area 3 in or cm W8 hardness x cohesiveness - WINESS gummincss x springiness - SPRINGINESS distance of area 2 in or cm FRACTURABILITY‘ "' Operator calculated from the graph chart. Figure 6. Typical TPA curve for objective evaluation of food texture (from.manual of TMS-90 Texture Press, Food Technology Co., Rockville, Maryland) 41 sequence effect on food preference (Eindhonen et al. 1963). Numerical scores for each quality characteristic were assigned to the ratings as presented in Figure 7. Statistical Analysis The "QPRO" and "MSTAT" computer programs were used to assist data computation and statistical analysis. Analyses of variance were determined using the subprogram FACTOR. Mean squares were reported after rounding, and significant probability levels were set at p50.05(**), p50.01 (*). Coefficient of ‘variation (%CV) ‘which expresses the standard deviation as a percent of the mean was calculated. All mean values were reported plus or minus one standard deviation. Least significant difference (LSD) mean separation were used for single classification analyses by the subprogram Range. LSDmfi values were indicated to show the significant differences between means. 42 HNU-hUiO‘Q l-‘NUhU’iOtQ II II II II II II II II II II II II II II Htouietn0\q n "II" "II" FLAVOR extremely good fresh soybean curd flavor very good fresh soybean curd flavor slightly fresh soybean curd flavor neither fresh nor off flavor slightly off-flavor strong off-flavor extremely off-flavor TEXTURE extremely smooth very smooth slightly smooth neither smooth nor course slightly course very course extremely course ACCEPTIBILITY like extremely like very much like slightly neither like nor dislike dislike slightly dislike very much dislike extremely. Figure 7. Quality characteristics and hedonic scale terminology used for tofu evaluation Study I. Evaluation of tofu made from 26 soybean cultivars and breeding lines Hypotheses Ho 1a: Genetic stock of soybean does not have a significant.impact.on.seed.size and.composition of soybean. 1b: Genetic stock of soybean does not have a significant impact on yield and textural properties of tofu. 1c: Location of soybean seed production within Michigan does not influence tofu quality characteristics. 1d: Year of soybean seed production within Michigan does not influence tofu quality characteristics. Ho 2: The selection of superior tofu production potential cannot be made based on physical and chemical characteristics of the seed. Objectives The objective of this study was to identify the characteristics of soybean that affect the yield and textural properties of tofu from screening 26 soybean cultivars and breeding lines produced at two locations (Ingham & Lenawee counties, MI.) during two crop seasons (1990 & 1991). Methodology Data of seed size were measured on 100 seed weight. The composition (protein & oil) of soybean were conducted at USDA 43 44 lab in Pearia,Illinois. Tofu was prepared using a micro laboratory method which enabled product to be measured as fresh tofu obtained from soymilk made from 100 grams of soybean using 10:1 waterzbean ratio. The textural preperties of the small scale tofu was measured using texture press TMS-90. Results and Discussion m Mean values, standard deviations and least significant difference (LSD) mean separations for protein, oil contents and seed size of soybeans from two seasons (1990 & 1991) were summarized in Table 8. Analysis of variance of these data are presented in Tables 9 to 11. Significant differences were found for protein and oil contents of soybeans between two locations from 1990 seasons. Soybeans from Ingham county showed higher protein content than seeds obtained from Lenawee county. However, soybeans from Ingham county had lower oil content compared to that from Lenawee county (Figure 8) . Year of soybean produced also resulted in significant differences in protein and oil content of soybean. Soybeans from 1990 showed higher protein.and lower oil contents compared to that from 1991 (Figure 9). Soybean cultivars and breeding lines also showed significant differences among protein and oil contents. Protein content ranged from 41.3 in Elgin87 to 45.9 in Vinton81 with a average value of 43.1 for 1990 and from 39.4 45 Table 8.1. Mean value of proteinl, oil1 and seed 31222 of soybean from 1990,1991 Entries] 1990 1991 location protein oil seed size protein oil seed size (S) (t) (g/100 seed) (3) ($0 (g/100 seed) Vinton Ingham 47.0:1.0 17.8:0.6 23.8:1.1 43.3 19.0 26.6 Lenawee 44.910.3 19.2:0.2 27.4:0.9 42.8 19.8 25.7 Season Ingham 44.6:0.3 18.8:0.2 19.3:0.8 42.0 19.8 23.4 Lenawee 42.0:0.5 20.710.3 23.5:1.2 40.6 20.6 22.7 390010 Ingham 42.910.4 20.6:0.4 25.4:0.3 41.0 21.0 25.2 Lenawee 41.8:0.2 21.8:0.4 23.8:0.6 40.4 21.7 21.1 E90006 Ingham 44.5:0.2 19.4:0.1 23.8:0.3 41.4 21.2 24.3 Lenawee 43.0:0.5 20.7:0.4 25.7:0.4 42.5 20.4 22.4 ng s20-26 Ingham 41.7:0.4 20.6:0.3 20.8:0.2 40.8 19.5 20.5 Lenawee 43.0:0.1 l9.8:0.2 19.0:0.4 39.8 20.3 16.3 Century Ingham 44.6:0.5 19.5:0.3 18.8:0.6 43.5 19.1 21.7 Lenawee 44.5:0.1 19.3:0.1 21.8:0.5 42.3 20.1 20.6 E90011 Ingham 43.7t1.0 19.6:0.6 22.3:0.5 41.8 20.1 24.2 Lenawee 43.0:0.5 20.6:0.2 23.5:0.1 41.3 21.0 20.9 E90004 Ingham 45.020.5 18.9:0.6 23.2:0.6 41.6 19.5 25.6 Lenawee 43.0:0.1 20.1:0.1 27.1:0.6 42.4 19.5 25.3 E90001 ' Ingham 43.7tl.4 20.0:1.0 28.3:0.4 42.2 19.2 30.2 Lenawee 42.710.4 20.4:0.2 26.4:0.4 41.9 20.5 26.6 E90008 Ingham 42.5:0.6 19.830.1 23.9:0.7 42.5 19.6 23.8 Lenawee 43.3:0.5 20.1:0.4 26.7:0.2 40.9 20.3 22.6 E90007 Ingham 4S.010.8 19.3:0.7 24.0:0.8 41.3 20.0 25.7 Lenawee 42.0:0.2 20.6:0.3 25.1:0.7 39.6 21.4 22.4 Elgin 87 Ingham 41.5:0.3 20.8:0.1 19.7tl.3 40.5 19.7 20.1 Lenawee 41.2:0.2 20.9:0.1 20.5:0.6 39.2 21.2 20.3 Glh 9122 . Ingham 42.4:0.7 20.3:0.5 21.1:1.1 39.8 20.7 20.4 Lenawee 41.2tO.1 21.7:0.2 22.3:0.9 39.0 21.2 20.6 E90009 Ingham 43.3t2.0 19.8:1.2 22.2:0.5 40.8 20.1 23.9 Lenawee 41.8t0.8 21.2:1.3 23.4:0.6 40.2 21.0 21.6 LSD 0.05 1.267 0.86 0.79 1.124 0.74 0.75 46 Table 8.2. Mean value of proteinl, oil1 and seed size2 of soybean from 1990,1991 Entries] 1990 1991 location protein oil seed size protein oil seed size m m (9/100 seed) m m (g/100 seed) £90005 Ingham 44.4:0.4 19.0:0.1 22.010.7 40.7 20.6 24.0 Lenawee 40.6:0.2 21.810.2 21.9t0.6 40.1 21.9 22.4 E90012 Ingham 45.4tl.6 18.2:0.9 21.4:0.3 41.7 18.9 21.9 Lenawee 42.2:0.5 20.2t0.2 20.0:0.7 41.1 20.1 18.8 E90013 Ingham 43.5:0.S 19.110.2 19.7:0.6 41.6 20.1 23.5 Lenawee 43.7:0.1 19.7:0.1 21.110.5 40.4 20.6 20.6 E90003 Ingham 44.710.4 19.4:0.1 22.1fO.5 42.8 19.5 24.4 Lenawee 42.6:0.1 20.6tO.1 22.6:0.5 40.4 20.8 20.1 Sibley Ingham 44.6tl.5 19.2:0.8 17.5:0.3 40.5 20.9 23.7 Lenawee 40.7:0.4 21.3:0.1 20.5:0.8 39.1 21.9 19.9 A86-202207 Ingham 42.6tl.6 20.410.9 21.0:0.7 40.9 20.1 22.6 Lenawee 42.4:0.4 20.6tO.1 21.6:0.5 40.2 20.9 21.8 M83-504 Ingham 42.6:0.2 20.0:0.3 20.2:0.9 41.1 20.4 22.8 Lenawee 41.8:0.3 20.8:0.2 20.7:1.2 39.5 21.7 18.5 E90002 Ingham 43.8:1.0 19.6:0.7 18.410.9 39.7 20.2 23.5 Lenawee 40.310.2 21.2:0.0 20.7:0.5 39.2 20.9 17.7 Pio 93030 Ingham 41.8:0.9 20.6:0.5 18.1:0.3 41.6 19.7 20.7 Lenawee 41.9:0.2 21.2:0.3 21.120.2 40.5 21.4 22.2 M82-599 Ingham 44.3:0.3 19.6:0.0 20.4:0.9 42.1 19.4 21.9 Lenawee 42.7:0.5 19.7:0.2 20.1:0.7 41.2 20.8 19.1 Corsoy Ingham 43.9:0.6 l9.8:0.5 17.2:0.8 42.0 19.6 19.0 Lenawee 42.3:0.1 20.0:0.4 18.210.5 40.0 20.8 17.3 Ln85-S382 Ingham 43.9:0.4 18.0:1.0 21.2:0.7 42.8 18.9 23.6 Lenawee 43.6:0.2 18.9:0.0 21.010.S 41.0 19.8 20.7 LSD 0.05 1.267 0.86 0.79 1.124 0.74 0.75 1. Dry basis 2. 100 seed weight (g) 47 Table 9. Analysis of variance for protein, oil and seed size of soybean from 1990 crop year source of variance df protein oil seed size (%) (%) (g/100 seed) mean squares Main Effects location 1 so . 12 3: 24 . 13 5': 34 . 615" entries 25 3.788 1.848' 23.487" Two Ways location** 3* . *3 entries 25 1.886 0.652 3.079 Error 51 0.797 0.357 1.4 ecv 2.07 3 .03 5.4 ** significant at p<0.01 * significant at p<0.05 48 Table 10. Analysis of variance for protein, oil and seed size of soybean from 1991 crop year source of variance df protein oil seed size (%) (%) (g/100 seed) mean squares Main Effects entries 25 1.859"’ 0.716"’ 9.94" Error 25 0.298 0.13 1.52 %cv 1.33 1.77 5.55 ** significant at p<0.01 49 Table 11. Analysis of variance for protein, oil and seed size of soybean from 1990,1991 crop year source of variance df protein oil seed size (%) (%) (g/100 seed) mean squares Main Effects 3. .3 year 1 105.002" 2.31 " 1.527" entries 25 3.491 1.438 20.168 Two Ways year*entries 25 0.285 0.204 1.395 Error 51 0.648 0.217 2.97 %CV 1.91 2.31 7.8 ** significant at p<0.01 50 50 Ingham 40« ‘ Lenawee d r 30 -i Y W 3 120‘ 9 h t 10‘ 0 Figure 8. Mean values of protein and oil content of soybean from 2 locations over 26 entries during 1990 crop season 51 50 1990 40" s 1991 d ’ 30~ Y w e 20.04 20-34 1 20‘ W' 9 n t 10‘ 0 . Figure 9. Mean values of protein and oil content of soybean of 2 crop seasons over 2 locations and 26 entries 52 Table 13. Analysis of variance for yield and texture of 1990 tofu source of variance df yield hardness chewiness (9) (N) mean squares Main Effects location 1 267.97M 37.72. 9.47 entries 25 1086.75 479.73“ 73.9' Two Ways location* 3. entries 25 398.82 599.61 67.92 Error 51 357.71 207.74 42.35 %CV 8.59 14.14 23.3 ** significant at p<0.01 * significant at p<0.05 53 39 , A protein = 37.19-0.404*oil r=-O.748 38 .u £3 0" '73 3 37 >1 u 'o 39 .5 O 36 4.) o u n. 35 34 l I 119 all 21 2'2 21 oil ( %dry weight ) Figure 10. Inverse relationship between protein and oil in soybean during two crop seasons ' 54 chewiness) are presented in‘Table 12. Analysis of variance for tofu yield and texture of 1990, 1991 are summarized from Tables 13 to 15. The ANOVA of data (Table 13) showed the significant differences for yield, texture among 1990 soybean entries, but no significant. differences 'were found. between locations. However, significant differences were found in the interaction of locations with varieties for tofu hardness. Analysis of variance from 1991 data showed significant differences for yield and chewiness.among soybean.entries, but not for hardness. These may be due to the large difference in hardness between Ingham and Lenawee for Beeson (107.1 for Ingham, 80.1 for Lenawee) NKG 820026 (106 for Ingham, 83.2 for Lenawee) and Elgin 87 (105.2 for Ingham, 87.3 for Lenawee) (TABLE 12). Significant differences were also identified for yield and texture (hardness and chewiness) between crop seasons (Table 15). Tofu yield was also showed to be significantly different among soybean entries when data from two crop seasons were combined. However, there was no differences in texture (hardness and chewiness). Correlation coefficients between various physical and chemical characteristics of soybeans and final tofu are presented. in. Table 16. No significant correlations were obtained among these variables. Commercial trade experience has indicated that the traditional view for selection of large 55 Table 12.1 Mean values of yield and textural properties 1990 and 1991 tofu 1990 1991 vareties/ yield texture yield texture location (9) hardness chewiness (g) hardness chewiness (N) (N) Vinton Ingham 198.6:2.3 9?.2:3.6 26.8:2.1 236.110.9 95.3il.3 26.39:2.3 Lenawee 217.4:3.2 102.1:2.1 29.312.4 228.?11.5 93.3tl.? 24.4:1.7 Beeson Ingham 238.2:2.2 99.311.6 26.2:3.2 223.1:2.1 107.1:1.6 29.9:2.4 Lenawee 244.0:1.3 108.311.2 30.9:1.5 267.4:1.1 80.1:0.5 17.1:0.5 E90010 Ingham 212.5:0.6 109.5:1.4 34.110.9 245.1:1.5 83.510.S 19.2:1.7 Lenawee 237.311.? 95.3:2.1 27.411.3 241.6:1.S 88.912.1 19.5412.3 E90006 Ingham 217.5:1.1 121.9tl.2 37.9:0.9 217.510.8 81.3:1.0 18.110.5 Lenawee 242.711.? 105.5:0.4 32.9:0.S 239.8:0.8 89.111.1 20.710.2 ng 520-2 Ingham 215.2:0.6 105.610.8 30.110.5 211.7:0.3 10610.8 26.9:0.8 Lenawee 218.6:1.5 103.010.6 30.0:1.S 261.2:1.2 83.1:0.6 18.7to.2 Century Ingham . 243.910.9 91.411.2 25.0:1.7 234.712.1 86.2:1.6 18.010.6 Lenawee sW234.111.3 103.210.s 30.1:1.7 256.6rl.4 88.2:1.9 19.0:1.6 E90011 Ingham 228.911.0 103.8t1.5 28.4tl.2 219.3:0.5 93.5:1.3 24.4:l.3 Lenawee 204.710.2 109.7:0.5 29.711.5 l95.l:1.2 94.811.7 22.9:1.3 E90004 Ingham 236.1:0.5 112.0:1.8 33.010.S 226.9tl.6 81.8:0.3 30.9:0.6 Lenawee 211.411.? 86.2:0.6 32.4tO.8 227.7:0.6 86.2:0.9 32.4:1.1 E90001 ' Ingham 190.0:0.8 122.0:0.9 35.910.8 231.0:0.8 92.8:1.7 24.4:1.5 Lenawee 221.6:0.6 89.2:0.9 19.4:1.2 207.2:0.6 99.0:0.5 28.410.8 E90008 Ingham 196.710.5 120.510.8 33.1:0.8 213.010.5 88.1:0.8 16.010.7 Lenawee 200.610.9 114.510.S 30.710.8 188.610.? 99.210.8 17.2:0.9 E9000? Ingham 239.210.5 117.1:0.8 34.9tl.1 244.7:2.1 80.2:1.5 17.9:1.6 Lenawee 205.911.5 91.510.9 20.8:0.8 22?.2:0.9 81.6:1.6 16.311.1 Elgin 8? Ingham 23?.0:1.5 88.410.6 20.5:0.9 219.1:2.S 105.2:0.6 2?.1tl.5 Lenawee 219.4tl.6 83.711.5 21.0:0.8 237.0:1.1 81.3:1.5 16.111.? Glh 9122 Ingham 197.911.5 99.3:1.2 26.9tl.5 206.0:0.8 87.5:0.8 19.5:0.6 Lenawee 173.2:0.5 98.010.9 24.0:0.7 189.8:1.5 86.5:0.8 18.6:1.1 E90009. Ingham' 235.111.? 84.5:0.8 20.710.8 241.510.6 93.0:0.8 21.111.3 Lenawee 230.6:3.1 90.4tl.9 21.3tl.7 228.7:2.1 86.5:1.7 18.110.9 LSD(0.05) 29.3 35.? 12.0 31.4 14.1 6.6 56 Table 12.2 Mean values of yield and textural properties 1990 and 1991 tofu 1990 1991 vareties/ yield te u e yield texture location (9) hardness chewiness (g) hardness chewiness (N) (N) E90005 Ingham 227.411.8 109.012.6 31.712.4 236.311.5 88.310.9 20.110.8 Lenawee 213.610.8 89.012.3 22.911.5 224.?11.5 79.310.8 22.110.5 E90012 Ingham 199.110.6 92.910.5 24.810.8 202.110.6 8?.810.? 24.010.8 Lenawee 21?.012.1 118.611.8 31.410.8 220.411.5 92.910.6 24.810.8 E90013 Ingham 233.11l.8 98.312.1 26.?11.9 236.913.5 86.411.2 16.110.8 Lenawee 235.612.5 117.211.? 33.610.8 224.112.6 85.211.9 19.611.1 E90003 Ingham 229.?12.8 99.210.6 2?.210.9 246.912.? 95.710.8 25.110.6 Lenawee 233.612.3 97.010.8 25.310.5 239.812.6 90.910.5 23.310.7 Sibley Ingham 231.511.9 89.610.8 23.510.4 246.812.4 99.110.4 23.310.8 Lenawee 228.711.? 100.710.8 26.810.? 258.610.9 84.310.8 20.010.6 A86-20220 Ingham 241.212.8 96.910.6 24.511.6 231.510.8 98.110.5 26.210.8 Lenawee 213.612.5 99.810.? 26.810.9 236.113.0 94.710.6 24.810.5 M83-504 Ingham 1?8.612.1 115.710.8 32.610.5 189.412.5 8?.210.7 18.510.8 Lenawee 1?2.612.9 118.610.9 38.611.1 1??.?11.8 84.110.9 14.310.8 E90002 Ingham 21?.311.5 104.810.8 30.310.5 224.013.2 86.111.? 17.210.9 Lenawee 215.810.? 100.510.7 26.810.9 207.712.5 88.710.9 19.910.8 Pio 93030 Ingham 226.910.9 89.?11.2 21.610.9 248.312.5 89.611.4 21.610.9 Lenawee 178.011.9 179.210.8 4?.810.9 205.612.4 83.811.6 18.811.2 M82-599 Ingham 230.112.1 105.110.6 28.510.9 225.810.9 88.310.6 18.010.9 Lenawee 248.311.8 7?.310.8 16.910.8 234.512.6 82.210.8 22.610.5 Corsoy79 Ingham 223.511.2 106.110.8 29.71l.2 251.312.3 91.311.6 23.011.1 Lenawee 237.?12.8 95.211.0 23.910.7 242.312.5 82.411.5 13.411.3 Ln85-5382 Ingham 239.712.0 85.411.1 19.410.8 224.112.3 8?.110.? 20.011.6 Lenawee 230.712.? 81.111.3 1?.110.8 237.313.1 85.410.7 l9.410.8 LSD(0.05) 29.3 35.7 12.0 31.4 14.1 6.6 11== 2 Table 13. Analysis of variance for yield and texture of 1990 tofu 57 source of variance df yield hardness chewiness (9) (N) mean squares Main Effects location 1 267.97" 37.72.. 9.4. entries 25 1086.75 479.73 73.9 Two Ways location* 3. entries 25 398.82 599.61 67.92 Error 51 357.71 207.74 42.35 %CV 8.59 14.14 23.3 ** significant at p<0.0 * significant at p<0.05 1 58 Table 14. Analysis of variance for yield and texture of 1991 tofu source of variance df yield hardness chewiness (9) (N) Main Effects Mean square entries 25 $49.06* 38.85 25.86' Error 25 232.57 46.51 10.01 %CV 6.7 7.65 14.84 * significant at p<0.05 59 Table 15. Analysis of variance for yield and texture of 1990 and 1991 tofu source of variance df yield hardness chewiness (9) (N) Main Effects mean squares year 1 1065.02; 4187.57" 1145.33“ entries 25 1226.01 137.168 30.49 Two Ways year*entries 25 119.36 140.42 32.28 Error 51 220.89 170.52 21.74 %CV 6.65 13.66 18.94 ** significant at p<0.01 * significant at p<0.05 60 Table 16. Regression analyses and correlation coefficient between parameter of soybean and tofu ___Qr_qp_ygar §oybean intercorrelates r(90) r(91) r(90, 91) oil vs. seed size 0.068 -0.351 -0.119 Protein vs. seed size 0.098 0.536 0.202 Protein vs. oil -0.881 -0.754 -0.748 §oybean and tofu correlation Tofu yield vs. protein 0.068 0.111 0.017 Tofu yield vs. oil -0.114 -0.078 -0.109 Tofu yield vs. seed size -0.167 -0.002 -0.105 Hardness vs. protein 0.046 0.268 0.369 Hardness vs. oil 0.036 -0.361 -0.129 hardness vs. seed size 0.102. 0.145 0.091 Tofu intercorrelates Yield vs. hardness -0.407 -0.l48 -0.331 Yield vs. chewiness 0.132 0.035 0.246 Hardness vs. chewiness 0.829 0.585 0.844 61 seed size, high protein content are predictors of superior quality for tofu making. However; no evidence was demonstrated in this study to support this rationale. Conclusions Thezdata in this study showed significant.differences for composition (protein & oil) and seed size among soybean entries. Protein and oil content in soybean are inversely related. Significant differences are also found among soybean entries for yield and between crop seasons for tofu yield and textural properties, but not among locations. No correlations were found between composition (protein and oil), seed size of soybean and tofu yield and textural properties. Based on these results, null hypotheses Ho 1a, 1b and 1d were rejected and Ho 1c and Ho 2 were accepted. Study 11. Quality assessment of tofu nade from 10 soybean cultivars and breeding lines Hypotheses Ho 1a: Location of soybean production within Michigan does not have significant impact on the quality of tofu. 1b: Year of soybean production within Michigan does not have significant impact on the quality of tofu. 1c: Genetic stock of soybean does not have a significant impact on quality of tofu. Objectives The goal of this study was to identify the characteristics of soybean that affect the quality of tofu using 10 soybean cultivars and breeding lines produced at two locations (Ingham & Lenawee) in ,Michigan during two crop seasons (1990 & 1991). Methodology Tofu made from 10 soybean cultivars and breeding lines from two locations and two crop seasons were chosen for quality and sensory evaluation according to the physical and chemical characteristics of soybean (Table 7) such as hilum color, seed size and protein content. During the production.of tofu, the total solids of soybean milk was measured. After the production, tofu from same batch was divided into three portions: 1) physical analyses including color and texture, 2) 62 63 sensory evaluation and 3) chemical analyses including moisture, protein, fat, ash and tota1.dietary fiber. Tofu used for most chemical analyses (except moisture) was packed into clean aluminum dish and held at -1d%:cooler. Tofu in aluminum dishes were then freeze-dried for 24 hours. The lyophilized samples were ground to fine powder (30 mesh Wiley mill). The fine powder was held in glass vials stored over Caco2 in a desiccator prior to analyses. Results and discussion W The mean values, standard deviations and LSD mean separations for yield, color and textural properties of tofu are presented in Tables 17 and 18, respectively. Results of analysis of variance of these data are summarized from Tables 19 to 21. Significant differences were exhibited for color among soybean cultivars and breeding lines from either 1990 data or 1991 data except a value of 1991 tofu. The data in Table 21 indicated significant differences between years, among soybean cultivars and breeding lines for color (Figures 11 and 12). There was also significant interaction between crop year and soybean entries for color. Good quality of tofu is white or very light-yellow in color. All of the tofu products in this experiment had a light yellow color. The tofu produced by Tsai et a1 (1981) showed L varying from 65.5 to 69.6, a.L from -1.5 to -3.19, tn from 9.4 to 11.10. The data in this experiment showed higher L value 64 Table 17. Mean values for yield, hardness and color of 1990 tofu Entries/ yield hardness Color location (9) (N) L aL bL Vinton Ingham 198.6:2.3 97.2:3.6 80.2:0.1 -2.3i0.3 14.4t0.6 Lenawee 217.4:3.2 102.1:2.l 80.4:0.2 -2.1:0.3 14.410.2 Beeson Ingham 238.2:2.2 99.3il.6 80.4:0.5 -1.7i0.1 12.010.l Lenawee 244.0il.3 108.3tl.2 80.5:0.1 ~1.2i0.0 13.0i0.3 E90010 Ingham 212.5:0.6 109.Stl.4 80.5iO.4 -1.9i0.1 15.1:0.8 Lenawee 237.3tl.7 95.3:2.l 80.6iO.1 -1.8i0.0 l4.9i0.2 E90006 Ingham 217.5il.1 121.931.2 80.5i0.4 -l.8i0.0 lS.3:0.2 Lenawee 242.7il.7 105.5:0.4 80.5:0.1 -1.6$0.1 15.0i0.3 ng 520-26 Ingham 215.2:0.6 105.6i0.8 81.010.3 -1.2i0.0 12.030.0 Lenawee 218.6il.5 103.0t0.6 80.9:0.2 -1.4i0.1 ’13.0t0.4 Century84 Ingham 243.9:0.9 91.4:1.2 80.9:0.2 -1.8i0.2 13.5:0.3 Lenawee 234.1:l.3 103.2:0.5 80.7:0.2 -1.710.1 13.2:0.4 £90001 ' Ingham 190.010.8 122.010.9 80.3:0.2 -l.6t0.2 15.7:0.3 Lenawee 221.6:0.6. 89.2:0.9 80.420.l -1.7iO.1 14.6i0.l Elgin 87 Ingham 237.0:1.5 88.4:0.6 80.9:0.1 -1.610.0 12.8i0.0 Lenawee 219.4il.6 83.7:1.5 80.8:0.2 —1.7i0.2 12.9t0.1 Sibley Ingham 231.5il.9 89.6:0.8 81.0:0.2 -l.7iO.1 12.8:0.l Lenawee 228.7il.7 100.710.8 80.6iO.1 -1.4t0.3 13.0:0.2 Corsoy79 Ingham 223.5il.2 106.130.8 79.9:0.4 -l.5i0.3 12.8:0.2 Lenawee 237.7:2.8 95.2tl.0 80.1:0.2 -1.5i0.1 13:0.2 LSD(0.05) 25.7 22.5 0.7 -0.4 0.3 :1 II N 65 Table 18. Mean values for yield, hardness and color of 1991 tofu Entries / yield hardness color location (9) (N) L aL bL Vinton Ingham 236.1:0.9 95.3:1.3 80.1:0.3 -1.7:0.2 15.8:0.6 Lenawee 228.7:1.5 93.3:1.7 80.1:0.4 -2.0t0.1 15.8:0.3 Beeson Ingham 223.112.1 107.111.6 79.5:0.2 -l.310.l 13.510.5 Lenawee 267.4:1.1 80.1:0.5 80.4:0.3 -1.8i0.6 15.6:0.6 E90010 Ingham 245.1:1.5 83.5:0.5 80.0:0.0 -1.9t0.7 15.5:0.3 Lenawee 241.6:1.5 88.9:2.1 80.1:0.5 -1.6¢0.5 15.8:0.6 E90006 Ingham 217.5:0.8 81.3:1.0 81.0:0.2 -1.8i0.3 15.1:0.4 Lenawee 239.8:0.8 89.1:1.1 80.9:0.5 -1.8:0.7 15.1:0.4 ng $20-26 Ingham 211.7:0.3 106.0:0.8 80.0:0.2 ~1.8:0.4 14.5:0.6 Lenawee 261.2:1.2 83.1io.6 79.9:0.5 -1.9i0.6 14.5:0.8 Century84 Ingham 234.7:2.1 86.2:1.6 79.0:0.3 -1.7i0.2 12.2:0.3 Lenawee 256.6i1.4 88.2:l.9 78.6:0.1 -1.5:0.3 12.2:0.4 E90001 Ingham 231.0:0.8 92.8:1.7 80.2:0.4 -2.3i0.4 13.8:0.5 Lenawee 207.2:0.6 99.0:0.5 80.6:0.8 -2.l:0.6 13.9:0.3 Elgin 87 Ingham 219.1:2.5 105.2:0.6 80.030.6 -1.9t0.5 13.1i0.5 Lenawee 237.0:1.1 81.3:1.5 79.7:0.5 -1.7i0.9 12.9:0.3 Sibley Ingham 246.8:2.4 99.1:0.4 80.6i0.9 -1.8:0.2 13.8:0.8 Lenawee 258.6:0.9 84.3:0.8 80.1:0.1 -2.3:0.3 13.8:0.9 Corsoy Ingham 251.3:2.3 91.3:1.6 80.5i0.9 -2.1i0.5 14.1:0.6 Lenawee 242.3:2.5 82.4:1.5 80.3i0.7 -1.9i0.6 l3.9:0.6 LSD0.05 22.3 16.7 0.7 -0.5 1.1 66 Table 19. Analysis of variance for yield, hardness and color of 1990 tofu source of df color yield hardness variance (g) (N) L aL bL Main effects Mean Square Location 1 0.016. 0.030. 0.289. 783.40 157.09 Entries 9 0,353 0.158 4.453 554.11 218.64 Two way Location* 9 0.027 0.04 0.221 261.93 198.57 entries Error 19 0.112 0.03 0.127 296.18 184.95 %CV 0.420 10.84 2.620 7.64 13.45 ** significant at p<0.01 * significant at p<0.05 67 Table 20. Analysis of variance for yield, hardness and color of 1991 tofu source of df color yield hardness variance (9) (N) L aL tn Main effects Mean Square Entries 9 0.621' 0.078 2.539“ 225.46 32.92 Error 9 0.084 0.047 0.231 277.19 90.89 %CV 0.360 11.720 3.370 7.00 10.49 ** significant at p<0.01 * significant at p<0.05 68 Table 21. Analysis of variance for color, yield and hardness of 1990 and 1991 ' source of df color yield hardness variance (g) (N) L aL 1% Main effects Mean Square Year 1 2439”" 0.552". 3.969" 1643.53” 992.12“ Entries 9 0.224 0.083 3.572" 459.09' 55.16 Two way Year* 9 0.551" 0.082' 1.188" 91.72 83.96 entries Error 19 0.049 0.032 0.162 187.29 93.49 %cv 0.27 10.33 2.89 5.91 10.08 ** significant at p<0.01 * significant at p<0.05 69 100 El!“ 90‘ L(black O/White 100) I 1mm 3&5 1991 80" m-: mu fine-03¢: 50‘ 40" 'IOPOfl 30‘ b(ye110w +/b1ue -) 20" 13.6 14.2 O 0 CI ......... ............ oooooo 10" “CPD( 0 7:5 2: I ‘I . ,1 ........ I - .6 4.9 40' a(red +/green -) ’20 l I L50=0.142 L§0=-O.IZ Ls0s0.26 Figure 11. Mean values of tofu color for 2 years over 2 locations and 10 soybean entries 70 100 90‘ L LSD=0.32 a LSD=-0.26 \\\\‘ b Lspso,59 80- 70‘ "03:36:13 60- 50' 40-1 r10%-‘0‘) 30- 20- 10-1 u a . L ‘ -10 j f l I I 1 fi I I OSHU< A - Vinton B - Beeson C - E90010 D - E90006 E - NKG $20-26 F - Century84 G - E90001 H - ELGIN 87 I - SIBLEY J - consoy79 Figure 12. Mean values of tofu color from 10 soybean entries over 2 locations and 2 years 71 and.tk values. These differences may be due to the different instrument used by Tsai et al. which was an antometic color and color difference meter (Toyo Rika Instruments Inc.). Although the data from Tables 19 and 20 indicated soybean cultivars and breeding lines used had effect on the color of tofu , the differences were not easily detected by visual observations. Yield and hardness of fresh tofu from either 1990 data or 1991 data result in no significant differences between locations and among different soybean entries . However, differences existed between years for yield and hardness (Table 21 and Figure 13). Significant differences also existed for yield among soybean cultivars and breeding lines when combining data from two crop seasons (Table 21, Figure 14). W Sensory evaluation value in Table 22 showed most of tofu made in this experiment were fresh, smooth and acceptable to the panel members. Analysis of variance for these data are summarized from Tables 23 to 25. There were significant differences among soybean cultivars and breeding lines for flavor, acceptability and texture from either 1990 data or 1991 data. There was also a significant interaction between production location and soybean entries for texture from 1990 data. However, no differences were detected between locations. The.data in'Table 25 indicated Significant.differences between years except for texture. Flavor and acceptability of 1990 72 260 240- 220‘ 200‘ 180- 160- 140‘ 1991 120‘ 100‘ 80‘ 60‘ 40‘ 20'1 Figure 13. Mean values of fresh tofu yield and hardness for 2 years over 2 locations and 10 soybean entries 73 240* E. :: E? 2 E? IE_EI..SDsZZ.4 18°. .- . :- : :- t 160‘ :3 3 O O 1 1 100‘ yield (3/1003 seed) 88 ‘4 O 1 N O 1 O .4 .4 ..J .1 .1 .A - Vinton B - Beeson C - E90010 D - E90006 E - NKG $20-26 ,F - Century84 G - E90001 H - ELGIN 87 I - SIBLEY J'- CORSOY79 Figure 14. Mean values of tofu yield from 10 soybean entries over 2 locations and 2 years 74 Table 22. Mean value for1 sensory analysis2 of tofu 1990 1991 Flavor Accepti Texture FlavorAccepti Texture -bility -bility Vinton Ingham 4.7-0.2 4.4:0.1 4.7-0.1 4.3+0.2 4.0:0.3 4.2-0.6 Lenawee 4.2+0.0 3.8+0.2 4.0+0 3 4.0+0.8 4.5:0.2 4 7+0.4 Beeson Ingham 5.5:0.2 5.0+0.0 5.1-0.2 4.2:0.5 3.7-0.2 3.3ro.4 Lenawee 5.4+0.1 4.8+0.2 5.2+0.0 4.2+0.3 4.0+0.5 3 5+0.4 E90010 Ingham 4.7:0.3 4.8:0.2 4.8-0.2 3.5+0.2 3.2-0.3 3.3-0.1 Lenawee 4.5+0.2 4.4+0.1 4.6+0.2 3.3+0.3 3.5+0.1 3.5+0.2 E90006 Ingham 4.4io.3 4.2+0.3 3.7:0.0 3.7+0.2 3.5-0.5 3.0-0.3 Lenawee 4.7+0 3 4 3+0.2 3.8+0 2 3.0+0.3 3.7+0.1 3.8+0.3 ng $20-26 Ingham 4.5:0.5 4.5:0.8 3.8:0.2 5.0+0 3 4.3:0.2 4.5-0.0 Lenawee 4.2+0.2 4.3+0.2 4.1+0.1 4.7+0.2 4.5+0.6 4.7+0.2 Century84 Ingham 4.6io.4 4.4+0.1 4.2:0.2 4.3+0.5 4.2-0.6 4.7-0.2 Lenawee 4.4+0.1 4.6+0.1 3.8+0.2 4.5+0.1 4.7+0.1 4.5+0.3 E90001 Ingham 3.3-0.3 3.2:0.1 3.0+0.0 3.8+0 5 3.7:0.5 3.5-0.2 Lenawee 3.3+0 2 4.1+0.4 3.2+0.1 4.0+0.2 3 3+0.5 3.8+0.0 Elgin 87 Ingham 3.1+0.1 3.4+0.1 2.6+0.1 4.7+0 4 4.5:0.5 3.7+0.5 Lenawee 3.3+0.3 3 5+0.2 3.6+0.4 4.2+0 3 4 0+0.3 3.7+0.5 Sibley Ingham 4.6-0.4 4.8:0.3 4.7+0.1 4.2+0.3 4.3:0.3 4.0-0.2 Lenawee 4.3+0.3 4.2+0.1 4.1+0.1 5.0+0 3 4 5+0.5 5.0+0.3 Corsoy Ingham 4.4-0.4 4.2:0.3 4.3+0.2 3.8+0.0 3.7:0.4 4.5-0.2 Lenawee 4.0+0.5 3.8+0 2 3 5+0.2 4.2+0 3 4.0+0.2 4.2+0.5 LSD 0.05 0.9 0.7 1.1 0.7 0.6 0.7 1. n = 6 2. flavor: 7 = extremely good fresh soybean curd flavor 1 = extremely off flavor texture: 7 = extremely smooth, 1 = extremely course acceptability: 7 = like extremely, 1 = dislike extremely 75 Table 23. Analysis of variance for sensory evaluation of 1990 tofu. source of df sensgzx gttzihgte variance . Flavor Acceptibility Texture Main effects Mean Square Location 1 0°252", 0.266.. 0‘005.. Entries 9 1.672 0.958 1.489 Two way Location* 9 0.079 0.105 0.286 entries Error 19 0.168 0.123 0.278 %CV 15.29 .12.26 13.08 ** significant at p<0.01 76 Table 24. Analysis of variance for sensory evaluation of 1991 tofu source of df sensory attribute variance Flavor Acceptibility Texture Main effects Mean Square Entries 9 1.474“ 0.331‘ 0.699" Error 19 0.101 0.07 0.088 %CV 11.09 8.66 9.58 ** significant at p<0.01 * significant at p<0.05 77 Table 25. Analysis of variance for sensory evaluation of 1990 and 1991 tofu source of df sgnsgty atttibute variance Flavor Acceptibility Texture Main effects Mean Square Year 1 0.2981'. 0.861" 0.165" Entries 9 0.585 0.389 0.749 TWO way n to st Year* 9 0.731 0.337 0.794 entries Error 19 0.065 0.085 0.114 %CV 9.19 10.03 11.13 ** significant at p<0.01 * significant at p<0.05 78 tofu were judged superior to the 1991 tofu (Figure 15). Differences also existed among soybean entries (Figure 16). There was also a significant interaction between year and soybean entries. gngmita; Analyses The mean values , standard deviations and LSD mean separations for chemical composition of soybean, soybean milk and tofu are summarized in Tables 26 and 27, respectively. The moisture content of the fresh tofu varied from 77.8% to 81.2% for 1990, from 80.1% to 83.1% for 1991. Although there is no recognized standard of identity for tofu moisture, generally commercially available hard tofu contains 75-79% moisture while the water content of soft tofu ranges from 82- 88% (Gebre, E.A. 1983). Moisture content of 84.7% and 85.9% for tofu products was also reported by Tsai et al. (1981) and Smith et al.(1960). Range:of the chemical composition (dry basis) of the tofu were listed in Table 28. About one half of the dry weight of the tofu was protein. The s for protein and fat are similar to the ranges of 46.03-52.5% and 16.69-23.54% reported by Lim et al.(1990). Total solids of soybean milk ranged from 5.3% to 8.2% for 1990, 6.0% to 7.8% for 1991. These data are relatively lower compared to total solids (9.09% tlo 9.9% ) repoted by Lim et a1 (1990). The variation of the total solids of soybean milk could be due to the different moisture content of soybeans or 79 S as! 4.31 1990 . 423 ERR 0 .. 1.. I. 1991 0 O m 5 v4 3‘ u «I .‘J H s > 0 2‘ >1 H O a) 5 U) 1 o I U Flavor-(150:0. 17) Acceptibi l ityuso-o. 19) TextureUIS) Figure 15. Mean values of sensory evaluation for 2 years over 2 locations and 10 soybean entries 80 flavor Lso=0.38 accept. LSDIO.“ texture LSDsOJoO‘ Sensory evaluation score 4.») l .’////Ill/lll/III/l/lllllllll A - Vinton B - Beeson C - E90010 D - E90006 E - NKG $20-26 F - Century84 G - E90001 H - ELGIN 87 I - SIBLEY J - CORSOY79 Figure 16. Mean values of sensory evaluation from 10 soybean entries over 2 years and 2 locations 81 Table 26. Mean values for proximate analysis of 1990 tofu. moisture protein1 fat1 ashl. fiber1 -total solids m m m m m m Vinton Ingham 81.2to.3 52.5t1.1 l9.9t0.6 15.710.2 0.7910.03 7.010.1 Lenawee 81.1:0.1 50.610.2 19.5t0.2 15.6t0.3 0.73:0.03 7.0:0.l Beeson Ingham 79.9:0.1 51.3:0.4 22.8:0.7 lS.9tO.2 0.65:0.01 7.0:0.1 Lenawee 79.7:0.3 Sl.SrO.2 22.3:0.l 14.6t0.4 0.720.02 7.1:0.2 E90010 Ingham 80.6:0.2 so.7:0.2 24.6:0.3 15.2t0.5 0.67:0.03 6.2:0.2 Lenawee 80.3:0.2 SO.610.3 24.4:0.5 15.5t0.2 0.65:0.03 6.3:0.2 E90006 Ingham 79.0:0.S 52.020.3 23.0:0.2 15.0t0.2 0.68:0.03 6.710.l Lenawee 78.7:1.0 52.110.4 23.0:0.3 14.4:0.l 0.67:0.03 6.4:0.2 ng 820-26 Ingham 78.5:0.3 50.8t0.5 22.1:0.2 15.610.2 0.6320.04 7.0:0.l Lenawee 79.0:1.l 49.8:0.6 22.1:0.7 15.4t0.2 0.64:0.03 7.010.2 Century84 Ingham 77.8:0.4 SZ.2:0.3 21.9:1.0 15.3:0.1 0.67:0.02 7.4:0.2 Lenawee 78.1:0.2 52.6:0.3 21.6:0.3 15.9:0.l 0.710.01 7.2:0.4 E90001 Ingham 80.8:0.2 52.2:0.4 23.2:0.3 lS.7t0.0 0.65:0.03 5.310.2 Lenawee 80.7:0.2 52.7:0.3 22.1:0.7 15.7t0.3 0.63:0.03 S.St0.4 Elgin 87 ‘ Ingham 80.2:0.2 50.0t0.2 22.7tl.2 15.8:0.1 0.72:0.02 6.3:0.2 Lenawee 80.3:0.l 50.0t0.6 22.8:1.3 lS.3tO.l 0.70:0.01 6.7:0.2 Sibley - Ingham 79.0:0.7 50.020.3 23.010.9 lS.2:0.2 0.66:0.03 7.1:0.2 Lenawee 78.7:0.3 50.3:0.4 22.7tl.0' 14.920.1 0.65:0.01 7.0:0.3 Corsoy Ingham 77.8:0.5 SO.7:0.2 23.0:0.l 15.610.l 0.70:0.02 8.2:0.7 Lenawee 77.8:0.2 50.4t0.4 23.2:0.S 15.8:0.1 0.68:0.03 7.5:0.2 LSD 0.05 1.3 1.2 2.1 0.5 0.06 0.7 1. dry basis 2.n= 2 Table 27. Mean value for proximate analysis 82 of 1992 tofu 1 moisture protein1 fat1 ash1 fiber total solids (‘1) ('3) (H (‘1) (H HI) Vinton Ingham 81.5:0.9 SO.1:0.2 23.3:0.6 15.0:0.S 0.69:0.1 7.1:0.8 Lenawee 81.7:1.2 50.4:0.6 23.8:0.8 14.7:0.5 0.65:0.09 7.4:0.S Beeson Ingham 82.9:0.5 52.5:0.8 22.0:0.l l4.8:0.7 0.68:0.07 6.9:0.4 Lenawee 81.2:0.S 52.3:0.6 23.1:0.7 14.5:0.3 0.63:0.04 7.3:0.S E90010 Ingham 82.6:0.2 50.7:0.8 23.2: 0. 1 14.1:0.4 0.59:0.04 6.8:0.7 Lenawee 82.6:0.3 50.1:0.3 23.6: 0. 5 14.5:0.2 0.63:0.04 6.8:0.6 E90006 Ingham 80.0:0.S 50.3:0.7 24. 1:0. 3 14.2:0.2 0.67:0.02 6.5:0.7 Lenawee 80.4:0.S 49.4:0.3 23. 6:0. 5_ 14.6:0.1 0.71:0.05 6.4:0.6 ng 820-26 Ingham 83.1:0.S 51.3:0.S 22. 9:0. 7 14.8:0. l 0.77:0.2 6.1:l.l Lenawee 82.6:0.7 50.4:l.2 22. 2:0. 9 14. 8: l. 3 0.71:0.06 6.0:0.8 Century84 . Ingham 81.7:1.0 52.9:0.6 21.2:1.1 14. 6:0. 3 0.68:0.08 7.5:1.0 Lenawee 81.2:0.4 52.6:0.7 21.8:0.9 14. 5:0. 8 0.71:0.09 6.8:0.l E90001 Ingham 82.1:0.7 53.1:1.2 22.1:0 4 15. 0:0. 5 0.75:0.1 7.2:0.7 Lenawee 81.2:1.6 53.3:0.S 23.0:0.S 15. 5:0. 4 0.79:0.04 7.5:0.8 Elgin 87 Ingham 80.1:0.S 51.3:0.7 23.2:0.S 15. 2:0. 4 0.73:0.05 7.5:0.S Lenawee 80.5:0.7 Sl.4:0.5 23.7:0.5 15. 2:0. 8 0.74:0.04 7.8:0.l Sibley Ingham 82.1:0.7 51.6:0.4 24.2:0.l 14.8:0.6 0.69:0.1 6.7:l.2 Lenawee 81.8:0.S Sl.4:0.6 23.6:0.7 14.6:0.5- 0.61:0.08 6.6:0.5 Corsoy Ingham 80.2:0.7 51.2:0.8 21.9:0.6 14.4:0.6 0.65:0.12 7.0:0.S Lenawee 80.1:0.S 49.7:1.6 21.2:OLS 14.6:0.3 0.58:0.06 7.1:0.8 LSD 0.05 1.03 0.91 1.12 0.46 0.07 0.52 1. dry basis 2.n=2 83 Table 28. Range of tofu chemical composition in two crop seasons Composition 1990 1991 Protein‘ 49.8-52.7 49.4-53.3 Fat' 19.5-23.2 21.2—24.2 Ash‘ 14.4-15.9 14.1-15.5 Fiber' 0.63-0.79 0.58-0.79 * % dry weight 84 to different moisture solubility and extractablity of some of the components (Lim et a1, 1990). Analysis of variance of these data are presented from Tables 29 to 31. Significant differences were found among soybean entries for chemical composition of soybean, soybean milk and tofu from either 1990 data or 1991 data except oil in 1990 (Table 29, Table 30). There were significant interactions existed between location and soybean entries for protein and fat content of soybean from 1990 data. The mean squares repoted in Table 31 indicated significant differences between years for protein content of soybean, fat, ash, moisture content of tofu and total solids of soybean milk (Figure 17). Soybean cultivars and breeding lines also showed significant differences in all chemical composition of soybean, soybean milk and tofu (Figure 18) . Although these differences are statistically significant , it is likely these differences are not of sufficient magnitude to influence general tofu quality characteristics. The mean values, standard deviations and LSD mean separations for mineral content of 1990 soybean and tofu are presented in Table 32. Analysis of variance of these data are presented in Table 33. Significant differences were detected among soybean cultivars and breeding lines for calcium and phosphorousicontent.of both soybean‘and.tofu. Differences were also exhibited between locations for phosphorous content of tofu and there was significant interaction between location 85 mo.ovd um osmofluflcmflw 4 Ho.ovm um osmofluficmflm 44 mm.m w w an o Hm.H w v vH.H mm.m nm.a >Uw mH.o Hoo.o mm o mo.o mm o em.o mm.o mam.o ma uouum mmwuucw No.0 Hoo.o mo 0 vH.o va.o mm o .mn.o .mo.m m scofiumooq %mz 039 :me ..mo.o ..mm.m ..mm.o HH 0 ..mm.m ..HN.N ..bmb m wwwuucm “No.0 0.0 Ho.o H.o vm o mm.o mH.m whoa H coflumooq mumsqm cmmz muommum new: Aw- Amy Aw- Aw- Am- va Aw- Aw- mcflaom Hmuob umnflu menumflos nmm Hflo cflmuoum HHo cflmooum mocmflum> xHHE cmmn>om Smob cmemOm mo uo mounom madame came so mflmxamcm HmoHEmno MOM mosmflum> mo mwm>amc4 .mm manmh 86 mo.ovm um unmoduwcmfiw « Ho.ova um assuauwcmwu «« ~n.n -.m om.o mn.a ma.~ mn.o ma.~ oe.a >ow nmo.o aoo.o mo~.o meoo memo none 36 :6 ma uouum :oev.o neoo.o :vam.H-.mms.o :mmq.s :eee.~ uwvm.o :ms.~ a mmauusm mumsvm coo: muomuuo Cam: .8- A»- -e. Awe -w- -»- -s- -»V mowaom Hmuou sense ousumwos 2mm Hfio cfiououa Hwo samuoum mocmwum> waE cmmn>om suoe cmwn>om up no mousom msasmm Haas no momzaccm Hmofisozo qu mocmwnm> uo mwm>amcc .on dance 87 Ho.ovm um uCMOMHMCOMm as m~.n ma.¢ «v.0 no.H ob.a Hm.o mh.~ mm.H >Uw hm.o Hoo.o mNH.o wo.o mma.o >H~.o an.o am.o ma uouum mmfiuucm :mba.n :moo.o :Hmn.d eva.o :oa.m :mvn.a. mm.o Hm.o m «use» >63 O39 :mnn.e :noo.o :nm.~ :Hmm.o :on.~ :mwo.n :mm>.H :m>.m m mmfiuucm :mnm.o o.o :ooo.av :mno.v :on.a e~.o mam.o :Hm.mn H Mama mumsom new: muomuuw ages A»- Aw- -e- As- As- .85 -*- A». mowaom Hmuou hogan ousumwos 5mm Hfio :fimuoua Hfio cwououm mocmwum> Mafia cmmn>om shoe cmwn>om up no mousom maesmm same 6:6 came so ucmuuwmcoo Hmowemzo uoH menswum> mo mfim>am:< .Hn manna 88 a . 5:5:5: I 55 51.2 51.3. 555555 55:25:55: eeeeeee ssssss eeeeeee ssssss ...... eeeeee ...... ...... eeeeee eeeeeee ssssss ...... ...... eeeeeeee eeeeee ssssss ...... Y 55%.; .;.:.;.:.;.: s 25 ' 555555 5:133:23: 22,5 22.9. b:e:e:o:e:e: ............ ............ eeeeee ............ sssss ....... eeeeee ...... ssssss ssssss 15.4 “.7 ........... .............. eeeeee ........... .......... DI ''''''''' eeeeee eeeeee eeeeee '''''''''''' eeeee DDDDDD ssssss eeeeee eeeeeeeeeeee ooooooo ....... 000000 eeeeeeeeeeee ...... nnnnn eeeeeeeeeeee eeeeee ssssss ............ ...... ............ ssssss ”*5 , rfikasn. e(L$DII0.23)\sh(L80-O.16) Figure 17. Mean values of proximate analyses for 2 years over 2 locations and 10 soybean entries 89 120 100‘ am u e i g 40‘ h t 20‘ I F I H I J o -I-I I finfi . A 8 c 0 [:3 Putnam-0.68) m ass-o. 59> 8.50.50.11.35) Q FxborQSDID. 05> A - Vinton B - Beeson C - E90010 D - E90006 E - NKG $20-25 F - Century84 G - E90001 H - ELGIN 87 I - SIBLEY J - CORSOY79 an values for chemical anaylyses of tofu from 10 pi e 18. Me gur bean entries over two years and 2 locations soy 90 Table 32 Mean value of Ca and P of 1990 soybean and tofu Ca P (PPm) (ppm) Soybean Tofu Soybean Tofu Vinton Ingham 2330:70 42650:1550 6450:100 7125:55 lenawee 2560:200 42950:1950 6260:290 6550:350 Beeson Ingham 1610:130 40100:300 6330:150 6130:30 lenawee 2430:40 38000:1500 5495:275 5935:75 E90010 Ingham 2330:190 40050:1050 6310:230 6970:190 lenawee 1870:50 39700:400 5555:585 6010:340 E90006 Ingham 1865:125 39300:0 6750:80 7635:105 lenawee 1750:40 38250:1350 6200:180 7950:110 ng s20-26 Ingham 2415:85 42000:0 6275:325 6730:640 lenawee 2435:5 40950:950 5205:565 7105:705 Century84 Ingham 2410:80 43000:1100 6280:330 7620:110 lenawee 2425:5 43400:600 5185:565 66951115 E90001 Ingham 2330:190 40090:2250 6180:100 6320:120 lenawee 1875:55 37600:1400 6025:35 6145:75 Elgin 87 Ingham 1815:65 39950:150 6330:250 7310:5 lenawee 2435:35 40000:1200 6075:85 6248:428 Sibley Ingham 1860:120 40550:250 6750:60 7590:220 lenawee 1755:35 38950:650 6215:165 7085:175 Corsoy79 Ingham 2340:70 43400:1500 6280:330 7610:220 lenawee 2565:205 43300:100 5685:65 6440:50 LSD 0.05 319 3365 844.5 1060 91 Table 33. Analysis of variance for mineral content of 1990 soybean and tofu source of Soybean Tofu variance df Ca P Ca P Main effects Mean Squares Location 1 35402.5 3642122.5 6806250.0 2315534.4“ Entries 9 247758.1“‘ 312650.3“ 13823583.3“ 1087046.2” Two way Location* 9 142269.2“ 115216.9 956250 310581.1 entries Error 19 23222.5 l62788.8 2584460.5 256704.7 %CV ** significant at p<0.01 92 and entries for calcium of soybean. Correlation coefficients among various physical and chemical characteristics of soybean, soybean milk and tofu were presented in Table 34. Based on the author's experience, hardness values between 90-120 N are'generally in the range of desirable texture of tofu. However, no relationship was found between texture attribute in sensory evaluation and hardness and chewiness measured by TPA cell. A moderate correlation was obtained between soybean.protein.and protein of tofu from 1990 data. However , this correlation was not observed from 1991 data. Wang et al. (1983) and deMan.et al. (1987) also reported a positive correlation between the protein content of beans and the tofu produced. There was a moderately positive correlation between the fat content of soybeans and the fat content of the tofu from both 1990 data and 1991 data. This relationship confirms that a soybean variety which is high in fat will produce tofu with higher fat content as previously reported by Lim et al. (1990). The fiber of the tofu are found to be negatively correlated with yield of tofu and positively correlated with hardness of tofu from 1991 data. A significant correlation was obtained between phosphorous content of soybeans and.phosphorous content of tofu (r=0.93) by lim.et a1 (1990) . This correlation is relatively low in this experiment. However, a moderate correlation between calcium content of soybeans and calcium content of tofu was detected. Conclusions 93 Table 34. Correlation Coefficient between soybean, soybean milk and tofu r(1990) r(1991) r(1990,1991) Tofu intercorrelates yield vs Tprot.l -0.126 -0.131 -0.113 yield vs Toil‘ 0.105 0.135 0.129 yield vs moisture -0.31 0.024 0.094 yield vs fiber -0.044 -0.542 -0.328 hardness vs Tprot. 0.264 0.265 0.219 hardness vs Toil 0.016 0.017 0.024 hardness vs moisture -0.016 0.305 -0.262 hardness vs fiber 0.058 0.515 0.248 hardness vs TCa‘ -0.055 ---------- hardness vs TPl 0.103 ---------- Tprotein vs Toil -0.113 -0.327 -0.27 Sensory texture vs hardness 0.145 0.189 0.162 Sensory texture vs chewiness 0.324 0.236 0.286 S9x2ssE_milk-sns_tgfu_sgrrslsts§ yield vs total solids 0.147 -0.201 0.186 hardness vs total solids -0.04 -0.153 -0.137 Soybean and tofu correlates hardness vs SP2 0.238 ---------- hardness vs SCa2 0.147 ---------- Tprot. vs Sprot.2 0.493 0.194 0.237 Toil vs Soil2 0.518 0.478 0.57 TCa vs SCa 0.597 ---------- TP Vs SP 0.331 ---------- 1. Tofu components: Tprot., Toil, TCa and TP are protein, oil, Calcium and Phosphorus in tofu. 2. Soybean cmponents: Sprot., Sfat, SCa and SP are protein, oil Calcium and Phosphorus in tofu. 94 In this study, soybean cultivars and breeding lines showed significant differences in color, sensory evaluation of tofu and all chemical compositions of soybean, soybean milk and tofu. Significant differences was also observed for fresh yield of tofu from data obtained during two crop seasons. Location of production of soybeans resulted in no significant differences in the quality of tofu except for phosphorous content of 1990 tofu. Year of soybean production exhibited significant differences in physical analyses (yield, color and hardness), flavor and acceptability of sensory evaluation and chemical analyses including protein content of soybean, fat, moisture, ash of tofu and total solids of soybean milk. Therefore, Ho 1a,1b,1c were rejected according to data obtained in this study. Study 111. Evaluation of bean curd made from soybean-dry bean combinations Hypothesis Ho: 1 the use of dry bean (Garbanzo and navy bean) does not affect the quality of bean curd. Objective Theigoal of this study was to investigate the possibility of producing a curd similar to tofu using selected dry beans and dry bean-soybean combinations. Methodology The procedure for preparing bean curd are same as for preparing soybean tofu except using 100g dry bean or 100g dry bean-soybean combination instead of 100g soybean. For the preparation of dry bean (DB) - soybean(SB) combination curd, total of 100g dry bean -soybean were used in the following percentage proportions on wt: wt basis: (1). 25DB:7SSB (2). 50DB:50$B (3). 75DB:2588. After curd production, the curds were evaluated by panelists, then physical and chemical analyses was conducted. Results and Discussion The use of dry bean (Garbanzo and navy bean) alone resulted in unsatisfactory bean curd. The bean curd made with Garbanzo, navy bean and 75% navy bean were very soft, less cohesive and did not have desired shape as did soybean tofu. All curd products containing greater level of soybean were firmer and were more acceptable than low level soybean curds. 95 96 Physical analysis Mean values, standard deviations and LSD separations for yield, textural properties and color of bean curd made from soybean (SB), navy bean (NB) and.Garbanzo (G) combinations are presented in Tables 35 and 36, respectively. Analysis of variance of these data are presented in Tables 37 and 38, respectively. The use of navy bean and Garbanzo resulted in Significant.decreases in fresh.yieldnwith.increasing levels of navy bean and Garbanzo in combination. The use of 75% navy bean and Garbanzo significantly increased the hardness of bean curd. The hardness decreased with increasing levels of navy bean and Garbanzo in combinations (Figure 19 and 20). gensory evaluation Mean values, standard deviations and LSD mean separations for sensory evaluation of bean curd.made from the combination of soybean, navy bean and Garbanzo are presented in Tables 39 and 40, respectively. Analysis of variance of sensory evaluation are presented in Tables 41 and 42 respectively. In general, judgements for the sensory properties of all samples ranged from a mean of about 2 to 5. The sensory properties of soybean curds were judged to be significantly better than the Ibean curd made from dry bean and soybean combinations. _Chemical Analyses The mean values, standard deviations and LSD mean s«aparations for total solids of bean milk and chemical Compositions of bean curd are presented in Tables 43 and 44, 97 Table 35 Mean value for yield, texture and color of bean curd made from soybean (SB) and navy bean (NB) combination combination yield texture color Soybean: (g) hardness L aL bL Dry bean (N) (ratio) 100$B:0NB 238.4i1.2 110.4:0.3 80.6iO.4 -1.1i0.3 11.9:0.3 7558:25NB 165.9:2.1 123.412.3 80.2i0.5 -0.9i0.6 12.4:0.5 50$B:50NB 100.4:4.3 79.8:0.6 78.6:0.6 -1.2£0.3 12.610.2 LSD 0.05 24.8 20.8 8.9 0.4 0.8 98 nN.o n¢.0 no.0 m.b n.HN m.0n no.0 0mg H.0HH.¢H ~.0H0.HI n.0Hm.hb v.NH¢.H~ o.~H¢.00H m.¢Hn.mm mumhummmm v.0Hv.ma m.0H~.HI m.0Hv.mh m.NHb.vn ~.mH0.m~H 0.NHm.hmH muomummom n.0H0.NH n.0HN.HI 0.0Hv.b> m.¢H~.hm «.mfim.0ba w.mH0.emH mOmmummmh H.0HN.NH ~.0Hv.al ¢.0HOJm> n.~Hm.vm v.NH¢.mHa 0.HHO.~¢N muoummooa Aosumnv :20 soon sno an as A mmmcflsmno mmmcoumn A00 “coon>om uoHoo musuxmu pamw> COwumcfinEoo cofiumcfinsoo Amov coon Oucmnuoo ocm Ammv cmmn>om Eouu moms than coon no uoHoo can musuxmu .oaow> now 05Hm> com: on manna 99 Table 37. Analysis of variance for yield, hardness and color of bean curd made from soybean and navy bean combination source of df color yield hardness variance (’15) (N) L aL bL Main effects Mean Square Combinations 2 1.482 0.065‘ 0.215' 9113.54 903.13” Replication 1 0.427 0.007 0.0 4,51 10,57 Error 2 0.082 0.002 0.005 19,54 1,43 %CV 0.36 3.71 0.57 2,54 1,15 ** significant at p<0.01 * significant at p<0.05 100 Table 38. Analysis of variance for yield, hardness and color of bean curd made from soybean and Garbanzo combination source of df color yield hardness variance (%) (N) L aL by Main effects Mean Square Combinations 3 0.193 0.021 1.108” 6501.47* 1341.55‘ 1341.55” ‘ , Replication 1 0.005 0.001 0.101 7.61 136.13 Error 3 0.045 0.011 0.041 15.83 67.22 %CV 0.27 8.57 1.56 2.38 6.46 ** significant at p<0.01 * significant at p<0.05 101 280 260‘ 24o. IOOSB:ODB HERE 220- 7558:2508 200~ \\\\\ 180 .. 5088: SODB 160- 140-1 123.4 120- 1104'” 100~ 1 79-3 .0. 1\ 40« E 20 t 3\ 0 1\ Yield(LSD=24.8) Hardness(LSD=20.8) hardness of bean curd.made from different Figure 19. Yield and . . d navy bean combinations soybean an 102 280 260‘ 240‘ 220‘ 200- 180‘ 160- 140‘ 120‘ 100- 80‘ 605 40‘ 20. §§§§§§§§§ : 5 :5 : 5 :5 1:5:5:5:5:5:3:5.1\\ r .5) Hardness(LSD-21.3) Figure 20. Yield and hardness of bean curd made from different soybean and Garbanzo combinations 103 Table 39 Mean value1 for sensory analysis2 of bean curd made from soybean (SB) and navy bean (NB) combination combination flavor accepti texture Soybean:Dry bean -bility 100$B:0NB 4.5i0.3 4.7:0.5 4.5i0.3 7588:25NB 2.2:0.3 2.0i0.6 2.SiO.7 50$B:50NB 2.0:0.7 2.010.? 2.2:0.7 LSD(0.05) 0.65 0.71 0.79 1. n = 6 2. flavor: 7 = extremely good fresh soybean curd flavor 1 = extremely off flavor texture: 7 = extremely smooth, 1 = extremely course acceptability: 7 = like extremely, 1 = dislike extremely 104 Table 40. Mean value1 for sensory evaluation2 of bean curd made from soybean (SB) and Garbanzo bean (GB) combination flavor accepti texture combination -bility 10088:0GB 4.010.4 3.710.4 3.510.5 75$B:25GB 3.011.5 2.510.3 2 210.3 5088:5068 3.511.3 2.510.8 3.810.3 2558:75GB 2.210.5 2.510.6 2 010.4 LSD(0.05) 0.76 0.82 0.67 l. n = 6 2. flavor: 7 = extremely good fresh soybean curd flavor 1 = extremely off flavor texture: 7 = extremely smooth, 1 = extremely course acceptability: 7 = like extremely, 1 = dislike extremely 105 Table 41. Analysis of variance for sensory evaluation of bean curd made from soybean and navy bean combination source of df Sensoty Attibute variance Flavor Acceptibility’ texture Main effects Mean Square Combinations 2 2 . 765' 3 . 86' 2 . 615" Replicates 1 0.001 0.007 0.082 Error 2 0.095 0.027 0.032 %CV 7.52 3.89 4.39 * significant at P<0-05 ** significant at p<0.01 106 Table 42. Analysis of variance for sensory evaluation f! of bean curd made from soybean and Garbanzo combination 7 source of df Senso tt variance Flavor Acceptibility texture Main effects Mean Square Combinations 3 1.191' 0°703” 0.778” Replicates 1 0.001 0.011 0.151 Error 3 0.051 0.025 0.071 %CV 5.94 3.66 6.3 ** significant at p<0.01 * significant at p<0.05 107 manna >up .H No.0 Nmo.o om.0 N0.H H0.H 0.0Hm.m H.0HH0.0 0.0Hh.md ¢.0HH.ON m.0Hm.hv 0.0HH.D H.0Hmh.0 N.HHm.©H n.0Hh.mH 0.0HN.mv v.0Hn.h n.0Hmm.0 «.0H~.md m.0Hb.HN v.0Hm.0m 1&0 va Awe Awe Rwy mofiaom Hmuou -umnfiu -nmm .umu _cfimuouo MH.H no.0 DmA m.OHN.mh mzomummom 0.0Hh.mb QZmNumwmh n.0Hh.Hm mzoummooa 180 some sno "comn>om musumwos COwumsflnsoo co«umcfinsoo A020 some >>mc can Ammv coon>om souu moms ouso Coon uo mwm>aoco mumswxoue now msam> com: .n§.0Hnma memos >uo .H 108 No.0 m50.0 mm.H HH.H 00.H MH.H no.0 and 0.0Ha.¢ v.0Hmm.0 n.0H~.nN N.0H~.ha v.0Hm.bv n.0Hn.mb mwnhummnm n.0Hm.¢ n.0Hbm.0 n.0Hm.mH n.0Hn.ON N.0HH.Nn 0.0Hm.mh moonummon o.HHO.n n.0HHm.0 H.0HH.>H «.0Hh.HN n.0Hn.Hn n.0Hh.hh mUnNummnh n.0Hm.n n.0Hmn.o n.0Hm.VH m.0H¢.NN n.0Hm.Nn n.0Hm.Hm m00umm00H mofiaom Hmuou 13min 2mm .umu ..fimuoum mus»m«o5 COMHMCHnEoo sawumanEoo Amov sown Oucmnumo ocm Ammv cmmn>om 8000 docs peso Coon no mam>amcm mumswxoua you 09Hm> coo: .vv dance 109 respectively. Results of analysis of variance of these data are summarized in Tables 45 and 46. The use of various combinations of dry bean - soybean. mixture resulted in significant differences in total solids of bean milk and chemical compositions of bean curd produced. The range of moisture contents.of the different combinations of curd in the study was 78.2%-81.7% for soybean - navy bean combination and 77.7% - 81.9% for soybean -4aarbanzo combination. These ranges fall at approximately the average moisture content of soybean tofu reported by previous workers (Gebre, E.A., 1983). Protein content of bean curd made from soybean - navy bean combinations were significantly lower compared to soybean tofu. Total solids of bean milk and fat content of bean curd of both combinations were significantly decreased with increasing levels of dry bean, while ash and fiber of bean curd were significantly increased (Figures 20 and 21). Conclusion: In this study, different soybean - dry bean combinations showed significant differences in fresh yield and hardness of tofu. The chemical compositions of bean curd were also significantly affected by different soybean-dry bean combination. The data in the sensory evaluation indicated bean curd made from soybean-dry bean combinations were less accept- able compared to soybean tofu. The null hypothesis estimated was rejected based on the results obtained in this study. 110 no.ovm um acmoMuacowm « Ho.ovm um procauwcmwm «« manna >00 .m sea» snaps .H no.n 50.0 ~.0 vn.0 «0.0 H~.H >0» a00.0 N~0.0 n00.0 b~0.0 -H.0 nH0.0 N uouum oo.o smo.o .hos.o «oo.o ~o~.o moo.o H sosumosaomn :H00.0 :~n>.n .nmh.v :Nn.n .nnn.v :~n.~ N coflumcHQEoo mumsvm coo: muoouuo Cam: sums: «and «So “5.0093 3.50305 moflaom Hmuou worsen”; 0020 soon xawa soon no no mousom sofiumcfinsoo coon >>mc one coonaom souu moms ouso soon «0 mwm>amso Houseono you mocmfium> uo wwm>umc4 .ne manna 111 no.0vm um acmofiuwcoflm « H0.0va um acmofiuacufim as demon >00 .m ouou amoum .H mm.H 0v.N n0.~ 00.0 mn.o fin.a >0» H00.0 0H~.0 nha.0 nma.0 n00.0 000.0 m uouum o.o 0.35 ..Seo woo oo.o ..Hoso H soap-8300... .m0.0 .mvnn .210 1.0.5. .nvoé ..nnn.~ n cowumcfinsoo mumsum coo: mucouuo Cam: Numb: Ema «So acflououa 0035on wagon Houou 0053.2; ouso coon xafiavcmmn up no wousom coflumcfinsoo Oncobuoo 0:0 cmwn>om 5000 docs ouso coon mo mfim>amcm Havasmno qu oocmwum> no mfim>~mca .00 manna 112 24 20 E1 100$B:0D8 l ‘533 7588:25D8 5&2 5088:5008 _e o l 010 m n a m o n m m m 3 l 1 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\w 0 5:25 I [TFTQ '. I a .o l T.S.(LSD=0.62) Fat(LSD=1.02) Ash(LSD=0.56)Fiber(LSD=0.06) ' ' ' 'ber F1 ure 21. Total solids of bean milk, fat, ash, and fi g content of bean curd made from different soybean and navy bean combinations 113 /////////////////////////////////////////x \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\v ' ///////////////////////////// \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ .' .'. , I 'n .. 7 l e I 1.8. (LSD=0.6Z) Fat(LSO=1.11) Ash(LSDI1.Z3)Fiber(LSOIO.O7) e. 0' Figure 22. Total solids of bean milk, fat, ash, and fiber content of bean curd made from different soybean and Garbanzo combinations Summary and Conclusion In screening the characteristics of twenty six soybean cultivars and breeding lines, significant differences were detected for protein, oil and seed size of soybean among different soybean entries, between two crop seasons. Correlation coefficients indicated that an increased protein level in soybeans was accompanied by a decrease in fat content. Tofu made from twenty six entries also resulted in significant differences in final yield and textural properties. Protein, oil content and seed size of soybean.have no relation with the yield and textural properties of tofu made. In the quality evaluation of tofu made from ten selected soybean cultivars and breeding lines, soybean entries resulted in significant differences in color, sensory evaluation and chemical composition of tofu. The correlation coefficients indicated moderately positive relationships between fat content of soybean and fat content of tofu. A moderately positive relationship also existed between calcium content of soybean and calcium content of tofu. The study from the evaluation of bean curd made from selected legumes indicated using Garbanzo and navy bean alone resulted in unsatisfactory products. However, three Garbanzo- soybean and two navy bean-soybean combinations produced acceptable bean curds. The sensory evaluation demonstrated 114 115 that the bean curd made from different combinations are less acceptable compared to soybean tofu. The bean curd made from different combinations showed higher fiber content and lower fat content than soybean tofu. Further Research In this study, soybean cultivars and breeding lines showed significant differences on the physical and chemical characteristics of tofu. However, the effect of soybean entries on yield and textural properties of tofu was not.great compared to the processing condition according to the author's experiences. For further research, processing conditions such as coagulation temperature, time and stir treatment should be investigated. For dry bean utilizatation studies, the possibility of producing a good quality curd from Garbanzo and navy bean by modifying the processing procedure, utilizing alternate technology or different cultivars of Garbanzo and navy bean should be investigated. 116 List of references .AOAC. 1980. 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