The manufacturing and ripening processes of cheese-like soy protein food using Saccharomyces fragilis as a yeast starter were investigated. Solid and protein yields in curd were approximately 70% and 90%, respectively. Heating condition at 50°C for 40 minutes adapted on curd formation process did not influence on the growth and fermentation activity of S. fragilis. The curd formation procedure using lactic fermentation with alcohol fermentation by S. fragilis reduced moisture content of the curd down to near 60%. The ripening rate (water soluble nitrogen/total nitrogen×100) of the product after 40 day's ripening was about 30%. The content of total free amino acids reached 654.8mg/100g, more than twice of that in sample without yeast inoculation, after 40 day's ripening. Amino acids liberated in comparatively high amounts were glutamic acid (132.6mg/100g), leucine (70.4mg/100g) and lysine (64.1mg/100g). The appearance of the product after 40 day's ripening had a smooth texture with small pores and yellowish white color. The product with pleasing aroma of alcohols and esters was evaluated by organoleptic test as good acceptance.

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Free fatty acids and neutral volatiles in cheese like soy protein food using Saccharomyces fragilis were identified and determined by gaschromatography. Amount of total free fatty acids reached the highest level through the ripening period (33mg/g) at 30 day's ripening, and decreased to 12mg/g at 40 day's ripening. Among the free fatty acids detected in the 40 day's sample, linoleic acid, was 4.8mg/g, equivalent to approximate 40% of the total amount of free fatty acids. Acetic and propionic acids as volatile acid were identified in 40 day's samples. Five carbonyl compounds; propanal, isobutanal, acetone, isopentanal and n-pentanal, were detected in 40 day's sample, but no methyl ketone except acetone were detected through the ripening period. Nine kinds of alcohol compounds were detected in 40 day's sample. Ethanol, active amyl alcohol and isoamyl alcohol which were at higher level among them through the ripening, were 95.9, 16.8 and 75.6ppm, respectively. Ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate and isoamyl acetate were detected in 40 day's sample and their amounts gradually increased during the ripening.

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Some properties of fumarase which was immobilized by radiopolymerization at a low temperature were investigated. The michaelis constant, K_m for L-malate increased by 4.6 times after the immobilization, but for fumarate it showed a value of 20 times as much high as that of native one. The equilibrium constant, K_eq was not so much changed by the immobilization. The optimum temperature of immobilized fumarase for L-malate was apt to go down. Thermal stability of immobilized fumarase became higher than that of native one. Immobilized fumarase also showed considerable activity under acidic area. The immobilized fumarase particles (13.6g wet) were packed in a column (9×250mm). L-Malate was continuously produced when 40-1000 mM fumarate (pH 7.5) were feeded into the column. The conversion rate of 1000mM fumarate to L-malate was estimated about 50% at the flow rate of 0.47hr_-1 (S.V.) at 25°C. In this flow test, apparent Km increased at the low flow rates. Higher concentration of the substrate declined the conversion rate, that would be due to shrinkage of the enzyme beads. In this column, it was observed that the initial activity reduced to about 80% after 120 days continuous operation in day and night at the flow rate of 0.47hr^-1 at 25°C.

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Pyruvate kinase (PK) was immobilized by the radiation-copolymerization method at a low temperature. From the mixture of PK solution (1ml), 30% acrylamide +2.7% N, N'-methylene bisacrylamide (1ml), 30% magnesium acrylate (2ml) and 30% sodium acrylate (1ml), the immobilized PK was prepared with good physical qualities and high retained activity of more than 80% of the original. Comparing with native PK the immobilized enzyme was more stable against heat and pH change. Immobilization decreased the Km values both for PEP and ADP, and shifted the optimum pH from 7.5 to 8.0. The immobilized PK was subjected to a 30 min. reaction repeatedly up to 20 times with little activity loss. Determination of ADP and hexokinase activity were successfully performed by use of the immobilized PK.

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Upper and lower layer Starch fractions were extracted from 60% extraction flours of four different kinds of wheat, and their fermentation characteristics were compared. No.1 C.W. R.S. wheat flour gave the highest amount of the upper layer starch fraction. During fermentation process, the upper layer starch fraction generated much carbon dioxide than the lower layer starch fraction, but the dough volume tends to shrink due to its poor gas retention capacity. Starch fractions from No.1 C.W.R.S. wheat generated much carbon dioxide than those from other three wheat. Tailing refined from the upper layer starch fraction of No.1 C.W.R.S. wheat comprised about 84% starch, 10% pentosan, 3% protein, 1% lipid and 0.3% ash. Eight solvents were examined to extract protein and carbohydrates from the tailing, and 8M urea proved to be most useful for this purpose. Chromatography of the urea extract of the tailing on a column of DEAE cellulose provided five fractions which were the complex of protein and carbohydrates. Each fraction comprised glucose, arabinose and xylose at the different ratio, and showed a different pattern in amino acid composition. From this study we presume that wheat tailing is the physical and/or chemical complex of starch, protein and pentosan.

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Textural characteristics of tofu-gel were investigated in order to obtain the fundamental information for the rational operation and control of tofu-making process. Textural qualities were evaluated by both organoleptic test and measurement on a Texturometer. A linear relationship was found between"hardness" and "adhesiveness" determined by the Texturometer. Sensory "adhesiveness" was not correlated with Texturometer "adhesiveness". On the other hand, sensory "hardness", an effective parameter to determine the quality of tofu-gel, was highly correlated with Texturometer "hardness". The desirable hardness of tofu-gel was estimated to be about 0.4 Texturometer Unit. From the results described above, Texturometer "hardness" appears to be valid and useful for the quality evaluation of tofu-gel and the establishment of the optimum operating conditions for tofu-making process.

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The effects of electrolytic reduction on suitability for making tofu were investigated using the U.S. soybeans (1979 crops, Ohio) stored under two different conditions. The soybean stored at 40°C (R.H.75%) for 30 days was regarded as "old soybean" and compared with "new soybean" refrigerated at 3°C. 1) Nitrogen solubility index of "old soybean" was fairly low compared with that of "new soybean", and remarkably increased by electrolytic reduction during the water extracting Step. 2) The amounts of sulfhydryl groups in the water extraCt from "old soybean" increased with the application time of electrolytic reduction and finally exceeded those obtained from "new soybean". 3) The ratio of 11S to 7S protein in the water extract prepared from "old soybean" was substantially equivalent to that of "new soybean" after the treatment of electrolytic reduction. 4) Kinugoshi-tofu prepared from" old soybean" was less in protein and free amino acids contents and softer than that from "new soybean". By application of electrolytic reduction to "old soybean" soaked in water, however, the tofu became similar to that from "new soybean" in the physical and chemical characteristics. 5) From the results described above, although the effects of electrolytic reduction on the soybean protein and other ingredients must be studied in detail, the application of the treatment to tofu-making process appears to be extremely useful.

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The measurement of the texture of cooked rice kernel by the two point mensuration method reported previously was compared to the data of the International Cooperative Testing on Instrument Methods for Texture of Cooked Rice cooperated by 11 laboratories. Our laboratory challenged the measurement of the individual cooked rice kernel level (one kernel) while other 10 laboratories used from 20 kernel to 150g of cooked rice for measurements. Moreover, we also challenged two point mensuration of cooked rice kernel. The correlation coefficent of the parameters (hardness and adhesiveness) between panel test and Tensipresser were highly significant. Also, the correlations of hardness and adhesivess between our laboratory and other 10 laboratories were highly significant. The correlation coefficent between adhesiveness and amylose content of cooked rice was over 0.98 in the data of our laboratory. The ratio of adhesivess/hardness of RD 6 (maximum) to that of IR 42 (minimum) calculated by the data of our laboratory provided the largest value among the laboratories.

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