Effect of air-exposure at low temperature on the activities of enzymes, ethylene production and browning in shredded cabbage was examined. Shredded cabbage was exposed to circulated cool air (1°C) for 2 hours (these were the treated samples), after that shredded cabbage was packed with polyethylene bag and stored at 20°C. (1) Browning (ΔE(Lab)) and the activities of polyphenol oxidase (PPO), peroxidase (PO) and phenylalanine ammonia-lyase (PAL) of shredded cabbage increased during storage. Browning and the activity of PAL in treated samples were lower than those of control samples, but the activities of PPO and PO of the treated samples were the same as those of control samples. (2) Ethylene production of shredded cabbage increased until 12 hours, after that it decreased. And the treated samples were lower in ethylene production than control samples. Following the increase of ethylene production, the activation of PAL was noted, and then the activity lowered as the ethylene production decreased. Browning and lignin formation of the treated samples was retarded, but respiration rate, ethylene concentration in package and phenolic content were not affected by this treatment. These results indicate that the reduction of ethylene production and PAL activation by the treatment may be concerned with the retardation of browning in shredded cabbage.

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A continuous system for the determination of ascorbic acid with an enzyme reactor electrode was developed and applied to the measurement of ascorbic acid in green tea produced by a microwave heating (2450MHz) and a conventional method. The system consisted of an enzyme reactor, an oxygen electrode, an A/D converter, a microcomputer and a peristaltic pump. The reactor (φ2×50mm) was packed with ascorbate oxidase immobilized on chitosan porous beads. One assay could be completed within 3min. The limit of detection was 1mg/100ml, the relative error was within 2%(n=40) and the response was linear up to 1000mg/100ml. The immobilized enzyme was sufficiently stable for at least 3 months at room temperature. The results for tea extracts correlated satisfactorily well with those obtained by the enzyme method (F-kit) and 2, 6-dichlorophenolindophenol method. These results suggest that the system proposed is a simple, rapid and economical method for the determination of ascorbic acid in foods. Furthermore. it was proved a larger amount of ascorbic acid remained in the green tea produced by microwave heating compared with that produced by a conventional method.

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Mechanical compression of bulk gels was investigated by using a compression-permeability cell consisting of a piston and a cylinder in the range of applied pressure, 20-1020kPa. The gels used in the present study were agar-agar gel as a natural polysaccharide gel, and heavy oil (A) gel and salad oil gel prepared by adding a gelling agent powder to each oil. In spite of the difference in the structure (between a gel and a solid-liquid mixture), the dewatering rate and the concentration distribution in the gel matrix could be analysed similarly to the filtration period followed by the consolidation period in the process of a solid-liquid mixture. For accurately determining the compressibility of gels, it was essential to take into account the bound water and half-bound water rather than dry mass of materials. Both modified filtration coefficient K_ω and modified consolidation coefficient C_e were correlated well with an applied pressure p and a gel weight concentration (s_g-s_g0) for the three kinds of gels tested. The calculated compression process based on the conventional theory of compression was compared with the experimental results.

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A method for measuring the dynamic viscoelastic behavior of starch during gelatinization was developed. In this measurement, starch was gelatinized after dispersed in an aqueous gel of 2% xanthan-gum solution, in order to simulate the gelatinization in solid food. Initially, peak and terminated temperatures of gelatinization were obtained from the curves of G' and G", and were equivalent to those by DSC. Starch granules were not disintegrated in this heat process, so the suspension turned to be a gel formed by swelled starch granules. Therefore, the viscoelasticity after gelatinization showed the characteristics of starch granules, and was merely influenced by the xanthan-gum solution concentrated and existed in crevices of the gel structure. The strain of vibration at dynamic measurements had to be minimized, or the curves of G' and G" were transformed. The specific values of temperature and viscoelasticity obtained from the curves of G' and G" made difference clearly among the varieties of starches. Influences of starch concentration on the viscoelasticity were different from the varieties of starches each other.

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To elucidate the effect of roasting conditions on antioxidative properties, an experimental roasting apparatus that could roast small particles such as sesame seed, rapeseed and others with well-controlled temperature and time was designed and built as a trial. Antioxidative activity was determined by weighing method at 60°C, and browning of oil was determined by absorbance at 420nm. It was shown that antioxidative activity developed significantly by roasting at above 180°C and increased with temperature. The activity of oil roasted at 200°C for 5min was superior to that roasted at 180°C for 30min, indicating that the development depends primarily on temperature. The increase in antioxidative activity paralleled that of browning. The tocopherol content (mostly γ-type) was not much changed by roasting even at 200°C, but that of sesamol increased with an increase in temperature: trace (150°C, 30min), 5.62mg/100g (170°C, 60min.) and 13.02mg/100g (200°C, 5min). When 16mg/100g of sesamol was added to sesame oil roasted at 150°C, antioxidative activity was far weaker than that roasted at 200°C, indicating the presence of some other active products in the roasted sesame oil.

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The changes in contents and extractabilities of some ingredients in tea leaves were investigated during manufacturing process of green tea (sencha). Infusions of tea leaves became clear and greenish on the latter half of manufacturing process of sencha. Total vitamin C of tea leaves decreased with the progress of the process, while total vitamin C in the infusions increased exceedingly during the first half of process. The contents of catechins and caffeine in tea leaves remain constant throughout the process from fresh leaves to sencha, while in the infusions, increased by the first half of process and then were held constant. Total free amino acids of tea leaves decreased with the progress of the process. In the infusions, the total free amino acid and theanine contents increased until drying process and then decreased by heating process (hiire). The content of sucrose in tea leaves decreased with the process and in the infusions increased extensively by the last two process (drying and heating). From these results, it was confirmed that all the seven processes in the manufacture of sencha were necessary to obtain the color and taste preferring as an infusion of sencha.

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Camembert cheese is produced by ripening with Penicillium camemberti or P. caseicolum. Remarkable proteolysis by proteolytic enzymes proceeds during this short ripening period. The degradation of milk proteins in the cheese during ripening was monitored by nitrogen distribution, SDS-polyacrylamide gel electrophoresis (PAGE), urea-PAGE and peptide analysis. The increase of water soluble nitrogen was greatest at the final stage of ripening. α_s1-Casein was degraded earlier than β-casein. αs1-Casein was degraded at first by chymosin. As the amounts of mold protease in cheese increased, degradation products of α_s1-casein and β-casein increased markedly on 10 days and after. These changes proceeded from the surface to the center. Most kinds of free amino acids increased a little during the first 2 days of ripening. Further rapid increase of them was observed during the following 10 days of ripening. In the increased free amino acids, Glu, Ser and Pro were found in quantity. Therefore, these milk caseins in the cheese were presumed to be degraded to low molecular peptides and amino acids. These results showed that proteolysis in the cheese occurred in the whole at the initial stage, and then it proceeded from the surface to the center in the final stage.

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Inhibitory effect of miso extracts on the melanogenesis in a highly pigmented clone (B16-C7) of cultured B16 mouse melanoma cells was studied. The nondialyzate of hot water extracts from miso A (rice miso type) had a slight inhibitory effect on the melanogenesis, but extracts from miso B (barley miso type) and miso C (soybean miso type) inhibited melanogenesis significantly. Suppression on melanogenesis by miso B extract in cultured B16-C7 cells was shown to be reversible.

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The application to the determination of sulfite in dried vegetables by the microbial biosensor method was examined. The recovery of added sulfite from 4 samples was more than 86%. The total sulfite was not detected by the microbial biosensor method. On the other hand, the modified Rankine's titration method was difficult to apply to determine sulfite in dried vegetables because of influence by sulfur compounds in dried vegetables. These results indicated that the microbial biosensor method was applicable to the determination of sulfite in dried vegetables including sulfur compounds.

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The ovalbumin hydrolysates (OA-H) prepared with pepsin showed stronger antioxidative activity than those prepared with trypsin or α-chymotrypsin against oxidation of linoleic acid in an ethanol-phosphate buffer (pH 7.0) system. Nevertheless, the potent synergistic effects of the OA-H with α-tocopherol were more attractive phenomena in their practical use because the antioxidative activity of α-toco-pherol was strongly enhanced by the combined use of the OA-H. Among the various kinds of peptides presented in the OA-H, the particular peptides with relatively high molecular weight appeared to act as an available synergist for α-tocopherol.

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To elucidate the mechanism of softening of combu by seasonings during cooking process, changes in the sugar component of cell-wall constituents of combu cooked in each model solution of water, 1% lactic acid, 5% sodium chloride or 10% sucrose were examined. The sugar component was examined for the pretreated material (hot ethanol insoluble fraction of the cooked sample in a model solution (dialyzed against water)), the water insoluble fraction (WIF), the alkali insoluble fraction (AIF) and the a-cellulose fraction fractionated by the method of CRONSHAW et al. Fucose, xylose, glucose, arabinose, galactose, cellobiose and other unknown saccharides were found in the pretreated material. Paper chromatography showed that the spots other than those of glucose, cellobiose and unknown saccharides gradually disappeared with the fractionation and the glucose spot became thicker by treatment with lactic acid and sodium chloride.

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To elucidate the mechanism of softening of combu by seasonings during cooking process, changes in the cell wall microstructure of combu cooked in water and model solutions of 1% lactic acid, 5% sodium chloride and 10% sucrose were examined morphologically by electron microscopy. Transmission electron microscopic observation revealed that the microfibrils of the sample only dialyzed against water were almost buried in the amorphous cell wall substance. The amorphous cell wall substance of the lactic acid-treated sample was removed and the shape of microfibrils changed from a round shape to a flat shape. The amorphous cell wall substance of the sodium chloride-treated sample was removed, but the microfibrils kept a round shape as well as water-and sucrose-treated samples.

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The application to the determination of total sulfite in 40 kinds of foods by the microbial biosensor method was examined. The recovery of added sulfite from 40 kinds of foods was more than 90%. The total sulfite values determined by the microbial biosensor method were coincided with those obtained by the modified Rankine's titration method. These results indicated that the microbial biosensor method was applicable to the determination of sulfite in various foods.

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Three kinds of brown rice were polished at several steps between 90-55% degrees, and the polished rice of 90% were cut into two parts by longitudinal and cross sections. These prepared rice samples were measured for the distribution of ten elements (P, K, Mg, Ca, Zn, Na, Fe, Cu, Mn and N) by the Inductivity Coupled Plasma Atomic Emission Spectrometer (ICP-AES). As the results, the following several observations were obtained. (1) No obvious differences between varieties and cropping areas were observed in the distribution oftrace elements in polished rice. (2) P, K, Mg and Mn were mainly observed at endosperm around the embryo and the outer layer of a grain. (3) Ca, Zn and Na were observed slightly more at around the embryo, and existed uniformly at the other parts. (4) N was uniformly observed at whole endosperm of a grain. (5) Fe was existing more at around the embryo. (6) Cu was observed slightly less at around the embryo and did uniformly at the other parts of a grain.

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Effects of the concentration of Tuyu, Japanese noodle soup, and pasteurizing conditions on the outgrowth from bacterial spores derived from raw soy sauce which is a main material of Tuyu were investigated. Tuyu having water activity (Aw) value of 0.95 required pasteurization at 90°C for more 30min or 97°C for 10min to prevent the outgrowth from spores. However, in case of Tuyu having Aw of 0.96, insufficient inhibition on the outgrowth from spores were demonstrated even by pasteurization at 97°C. In Tuyu containing 0.5% sodium citrate, thermal resistance of spores decreased and the outgrowth from spores was inhibited in a film bag by pasteurization at 97°C. It was suggested that bacteria with different physiological properties existed together in Tuyu, and two strains of spore forming bacteria designated B-1 and B-2 were isolated from Tuyu. Leakage of Ca ions from spores increased noticeably by heating at 97°C, and also remarkable leakage of Mg ions was observed when sodium citrate was added to spore suspensions. In the presence of sodium citrate, the total amounts of leaked metal (Ca, Mg) ions from B-2 strain which is highly sensitive to sodium citrate were about 18% higher than those of B-1, a low sensitive strain, by heating at 97°C.

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The contents of the proximate components, low molecular weight carbohydrates, polysaccharides, organic acids, and free amino acids in vegetative mycelia of basidiomycetes of six species (Aragekikurage, Auricularia polytricha; Enokitake, Flammulina velutipes; Maitake, Grifola frondosa; Kuritake, Naematoloma sublateritium; Nameko, Pholiota nameko; Hiratake, Pleurotus ostreatus) were determined. On a dry-weight basis of the proximate component contents were as follows; crude protein, 19.0-44.4%; crude fat, 2.6-5.2%; crude ash, 6.1-7.1%; carbohydrate, 44.6-72.3%. On the same basis, the low molecular weight carbohydrate contents were in the range of 1.6-15.5%. Trehalose, mannitol, glucose, fructose, arabitol and glycerol were detected in these vegetative mycelia, of which trehalose and mannitol were predominant. The organic acid contents were in the range of 0.3-1.2%, and 11 organic acids were detected. Malic, pyroglutamic, fumaric, citric, succinic and isocitric acids were predominant in these vegetative mycelia, and oxalic, lactic. acetic, α-ketoglutaric and formic acids were also found in all the vegetative mycelia. The polysaccharide contents were in the range of 30.2-67.7%. Acetic acid-soluble (glycogen) fraction was predominant in the polysaccharide fractions in these vegetative mycelia. The distribution patterns and contents of five polysaccharide fractions, that is, hot alkali-soluble fraction, alkali-soluble, acid-insoluble fraction (S-glucan), formic acid-soluble fraction (R-glucan), alkali-soluble, acid-soluble fraction and chitin, were low similarities among different species of vegetative mycelia. The free amino acid contents were in the range of 1.4-3.1%, and 20 free types of protein amino acids and 10 non-protein amino acids were detected in these vegetative mycelia. Alanine, glutamic acid, glutamine, serine, lysine, histidine and arginine were predominant. Non-protein amino acid contents were commonly low, but cystathionine, β-alanine, γ-amino-n-butyric acid and ornithine were proved to be widely distributed in these vegetative mycelia.

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Conditions for manufacturing a cheese product from two different kinds of cheeses (Gouda cheese and Cheddar cheese) without mixing were investigated. Initial process was done according to the ordinary method of Gouda cheese manufacturing. Subsequently, cheese of Gouda type (Gouda side) and Cheddar type (Cheddar side) cheeses were manufactured. Namely, a milled curd of Cheddar type cheese was layered on the pre-pressed Gouda type cheese, and then, pressed to make a final product. It was ripened at 8°C in 85% humidity. After ripening for 120 days, the percentages of water soluble total-nitrogen per total-nitrogen in Gouda side and Cheddar side were approximately 23% and 24%, respectively and those of 12% trichloroacetic acid soluble-nitrogen per total-nitrogen in Gouda side and Cheddar side were approximately 18.5% and 21.3%, respectively. In organic acid contents, propionic acid, acetic acid and orotic acid of Gouda side and lactic acid of Cheddar side decreased significautly. In both cheeses, α_s-casein decomposed more quickly than β-casein. These results suggested that the method described above was fruitful for making a new type cheese.

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