Tastes of shoyu (soy sauce) were investigated using the taste sensor with lipid/polymer membranes. Stable measurements were made by synthesizing a standard solution for shoyu. Twenty five kinds of shoyu were measured with the sensor, but classification to conventional three groups, i.e., koikuchi, usukuchi and sashimi, could not be made. On the other hand, it was found that tastes of three types of shoyu, which were produced in the same manufacturer, resembled each other. The similarity of shoyu in the same manufacturer was also confirmed by an amino acid analysis and a sensory test. The taste sensor will contribute to automated shoyu brewing.

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Continuous production of vinegar using hollow fiber module and two fermentors was studied to raise the acetic acid concentration and enhance productivity. Broth containing 10 to 12% (w/v) acetic acid and cells were produced in the first fermentor and supplied to the second fermentor. In the second fermentor, the cells were concentrated with a hollow fiber module and some portion of concentrated cells were discharged to suppress excessive increase in cell concentration. Medium feeding rate was set at 100ml/h and ethanol concentration in fresh medium was varied from 11 to 14% (v/v), solution containing 99.5% (v/v) ethanol was fed in the second fermentor at a constant rate. The discharge ratio ε (=F₂(out)/F₂: F₂(out) and F₂ are the discharging rate of cell-concentration broth and the feeding rate of the second fermentor, respectively.) was varied from 0.05 to 1. Although a steady state was achieved at the ethanol concentration of 11 to 13% (v/v), no steady state was achieved at 14% (v/v). The cell concentration Cx2 (g-dry cell/l) was expressed as a function of the discharged ratio.Cx2= 0.0496 (1/ε)+0.0973 By discharging some portion of concentrated cells from the second fermentor, cell concentration could be regulated by controlling the discharge ratio. A maximum acetic acid concentration of 143 g-acetic acidg could be observed at ethanol concentration of 13% (v/v) and discharged ratio of 0.1. In the first fermentor, acetic acid concentration, the yield and acetic acid production rate was 116 g-acetic acid/l, 0.93 g-acetic acid/1.304 g-consumed ethanol and 3.7 g-acetic acid/(l·h), respectively. Total acetic acid production rate and the yield of both fermentors was 2.83 g-acetic acid/(l.h) and 0.95 g-acetic acid/1.304 g-consumed ethanol, respectively.

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In order to utilize okara (the insoluble residue of homogenized soybean) as a food stuff, scientific preparation and specificity of chemical components of Okara-ontjom (Ontjom, a traditional Indonesian food which was fermented by Neurospora intermedia) were studied. Prepared Ontjom was a porous compact block as like as a sponge cake, the surface of which was covered with orange colored spores of N. intermedia. The mycelium of the mold proliferated on and in the wall of soybean cells and connected with each pieces of okara, and consumed some components of the cell wall of soybean. Fundamental conditions of Ontjom's preparation were established as follows. Okara containing 60% moisture was pressed by 1.1 g/cm² to give 2.5 cm in thickness and was sterilized at 121°C for 20 min, and then ontjom starter containing N. intermedia mold spores was evenly sprinkled over okara. After germination of spores, at 30°C for 18 hours with a fitted cover, the incubator cover was changed with a double layer nylon gauze (30 denier, 105×99/inch²) and incubation was continued at 25°C in 65% humidity for about 11 hours. Detecting sporulation, the medium was inverted. After the change of surface color to orange, the medium was allowed to stand for about 35 hours more. The component changes from okara to Ontjom were as follows. The protein content increased to 27% from 22% and was digested to smaller particles. The fat content decreased to 9% from 15% and the insoluble dietary fiber content decreased also. Ontjom had not the soybean-like flavor. The touch in mouth was smooth. The taste of fried Ontjom was resembled that of chicken. Consequently, Ontjom should be useful as a new tasted low-energy food material.

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The scavenging activity of extracts from edible flower petals and green tea was investigated by ESR (electron spin resonance). Thirteen kinds of petal extracts scavenged DPPH (1, 1-dipheny1-2-picrylhydrazyl) radical. The correlation coefficient of DPPH radical scavenging activity with the antioxidant activity was 0.787. The antioxidative activities of the petal extracts were examined by the method to measure the rate of discolaration of β-carotene coupled with the oxidation of linoleic acid. The petal extracts also scavenged the hydroxyl radical and superoxide. These activities correlated closely with the concentration of polyphenols measured by Folin-Denis method. The correlation coefficients of scavenging activity toward DPPH radical, hydroxyl radical and superoxide with the polyphenol content were 0.837, 0.707 and 0.904, respectively. Rose tea and green tea strongly scavenged DPPH radical. The tea extract had strong scavenged activity of DPPH radical. These results exhibited that the free radical scavenging activity primarily depends on the polyphenol content.

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In order to clarify thermal softening mechanism of vegetables, the softening rate of vegetable during a thermal process was investigated, comparing with the kinetics for β-elimination of pectin. A Japanese radish and a citrus pectin were used as samples. The cylindrical samples (7 mmφ× 30 mm in length) were cooked in water in a temperature range from 90°C to 110°C using a pressure-vessel. The softening behavior obeyed a first order equation. The softening rate constants and the activation energy were 0.17×10^-3 s^-1-2.30×10^-3 s^-1 and 146 kJ·mol^-1 from 90°C to 110°C, respectively. The pectin solution (0.5% in M/10 phosphate buffer, pH 6.5), which was sealed in a glass tube, was heated in the same temperature range as the Japanese radish. The β-elimination rate of the pectin was also analyzed by using a first order equation. The rate constants of fi-elimination and the activation energy were 0.33×10^-4 s^-1-3.73×10^-4 s^-1 and 143 kJ·mol^-1, respectively. Though the rate constants for softening of Japanese radish were approximately 10 times larger than those for β-elimination of the pectin, both activation energies were almost the same values. This result suggests that the softening mechanism of Japanese radish might be closely related with the β-elimina tion of the pectic substance in the radish.

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In order to obtain casein peptides at higher productivity, a filtration membrane automatic bioreactor has been developed. Total solid concentration of reaction solution in a reaction vessel was controlled automatically by adding substrate and deionized water to it. As the results, it was possible to operate for 24 hours with a constant permeate flux. However, when operated during 80 hours under the concentration ratio of substrate to enzyme : 5.0%/1.0% at an operation pressure of 150 kPa, the lowering of 8.1% of permeate flux was finally found. In general, permeate flux decreased with an increase in substrate concentration and increased with an increase in operation pressure. Total membrane resistance, R (m-1) was represented by the following equation, R=4.47+0.15C, where 4.47 was membrane resistance of itself and C was total solid concentration (%) of the reaction solution at 45°C. These results suggested that the decrease in enzyme activity and the accumulation of peptide which could not be further hydrolyzed and the increase in membrane resistance reduced the permeate flux after long operation period of up to 80 hours

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Analyses of proteins and their constituent amino acids were made in 7 major varieties of Japanese paddy non-glutinous rice and the results were compared with the previous data on the nutritive values of rice proteins. The protein contents were different among the varieties and their growing districts. The mean protein content was 6.7 g/100 g for the brown rices and 6.1 g/100 g for the milled ones. These values were lower by approximately 10% than the values in "Standard Tables of Food Composition in Japan, 4th revised". The amino acid contents were also different among the varieties and the growing districts. And the mean content was 6 369 mg/100 g for the brown rices and 5 851 mg/100 g for the milled ones. The constituent ratios of amino acids were different among the varieties, but the ratios for each variety were not different among the growing districts. The amino acid scores estimated according to the FAO/WHO standard pattern, 1973 (for adults) and FAO/WHO/ UNU standard pattern, 1985 (for preschool, 2-5 years of age) were different among the varieties and the growing districts, and the first limiting amino acid was lysine for both brown and milled rice. The mean amino acid scores estimated by the standard patterns of 1973 and 1985 were 67 and 64 for the brown rices and 62 and 59 for the milled ones, respectively, indicating that the scores for the milled ones are slightly lower than those in "Standard Tables of Food Composition in Japan, Amino Acid Composition of Foods, revised"

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To study the relationships between the coloration and the deterioration of frying oils, the following model-materials were applied. Namely, a series of 10mm square filter papers, made of glass-fiber, were soaked in the following various solutions, i.e. sodium chloride, glucose, sucrose, albumin, glycine, alanine, leucine and lysine. The dripping solution of the model-surface were removed. A series of the models were fried with rapeseed oil in 180°C, and obtained oil were measured by coloration, acid value (AV), carbonyl value (COV), anisidine value (An.V), conjugated diene content and viscosity. The following results were obtained. A series of the models soaked in amino-acid solutions, except lysine, show the vigorous coloration comparing to other models, and make the frying oil characteristically to red, and also make COV and An.V lower than even the fresh oil. For this reason, it is assumed that the carbonyl compounds, formed by deteriorated frying oil, changed to the browning pigments formed by the amino-carbonyl reactions with the amino acids from fried materials. And that there were not relating to the measurements of COV and An.V.

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The effect of aging of gluten-dough on the specific volumes of expanded products was studied. Before baking, gluten-dough was subjected to aging at various temperatures. Among the temperatures tested, incubation at 60°C for 20min gave the highest specific volume. Incubation at 70°C seemed to lead partial denaturation of gluten and gelatinization of starch, resulting in lower values of specific volume. Aging effects were studied at temperatures of 10°C or 30°C for up to 30 hrs. When gluten-dough aged at 10°C was baked, longer the aging length was, bigger the specific volume was. Aging at 30°C gave a different result. Specific volume became bigger until 8 hrs of aging, while prolonged aging gave smaller volume and 24 hrs and longer aging resulted in no expansion. The appearances of expanded products obtained by baking aged gluten-dough were spherical, plump and soft to the touch. The vertical section of the expanded product was packed with honey-comb structure, although one from gluten-dough aged more than 24 hrs at 30°C was small, compact and hard to the touch and had no honey-comb structure in vertical section The gluten-dough aged at 30°C for more than 10 hrs became exhausted and sticky, finally losing structural characteristics of dough. Some parts of gluten and starch seemed to be attacked by enzymes during incubation especially at 30°C. Certain degree of gluten degradation seemed to promote the expansion of yakifu when aged at 30°C. This was not true in the case of aging at 10°C. From the results obtained in this study, it was concluded that two types of aging effects occured in gluten-dough incubated at 10°C or 30°C.

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To raise the acetic acid concentration and enhance productivity, the effect of cultivation temperature in the second fermentor was studied on continuous production of vinegar using hollow fiber module and two fermentors. ln the second fermentor, the cells were concentrated with a hollow fiber module and some portion of concentrated celis were discharged to suppress excessive increase in ce11 concentration. Cultivation temperature was regulated at 30°C in the first fermentor and varied from 20 to 30°C in the second fermentor. Fresh medium of an ethanol concentration of 13% (v/v) at a rate of 100 ml/h was fed. A broth containing 117 g-acetic acid/l of acetic acid and 0.114 g-dry cell/l of cell was produced in the first fermentor and supplied to the second fermentor. ln the second fermentor, cells were concentrated with a hollow fiber module and was discharged at a discharge ratio of 0.1. The acetic acid concentration reached 156 g-acetic acid/l at 24°C and was constant below 24°C. Total acetic acid production rate and the yield of both fermentors was 3.0 g-acetic acid (l·h) and 0.94 g-acetic acid/1.304 g-consumed ethanol respectively. In the acetic acid production, the ratio of contribution of the first and second fermentor was estimated as 0.72:0.28.

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