The changes in the viscoelasticities and microstructures of gomatofus (kuzu starch 40g, water 450g, sesame seed 0-80g) prepared by simmering at a mixing rate 250rpm for 25min were investigated. This method of preparing gomatofu produced the most uniform size of air cells and honeycomb structure as described in our previous paper. Creep meter (RE-3305), scanning electron microscopy (SEM, S-800) and syneresis observation were employed. The creep curve for the gomatofu was analyzed by using a 4-element model, which consisted of Hookean and Voigt body elasticities (E₀, E₁) and Newtonian and Voigt body viscosities (η_N, η₁). The elasticities (E₀, E₁) of gomatofu increased and its viscosities (η_N, η₁) decreased with an increase of the sesame content. SEM observation revealed that kuzu gel starch had a thick branched network microstructure, and gomatofu had a fibrous microstructure which surrounds globular sesame oil. It was found that 3% of syneresis ratio from kuzu gel starch occurred during the first 2h after preparation, while none occurred during the same period for gomatofu (sesame contents 60, 80g). From these results, it can be seen that sesame components contribute to the strength and stability of kuzu gel starch.

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Asimple and rapid spectrophotometric method has been established for determination of γ- polyglutamic acid (γ-PGA) which is the sticky material in fermentated soybean food "natto". The method is based on the complex formation between γ-PGA and cetyltrimethylammonium bromide (CET). The complex could be determined by the measurement of absorbance at 400nm. The linear relationship was obtained between absorbance and γ-PGA concentration in the range from 0 to 54.85μg per 6ml of a reaction mixture. The complex formation with CET was not observed on glutamic acid, glutamylglutamic acid, levan and pectin. When γ-PGA prepared from "natto" was decomposed by γ-glutamyldepolymerase induced by Bacillus natto bacteriophage infection. viscosity of the reaction mixture decreased rapidly, while the absorbance of the complex with CET was not decreased. Therefore, it was confirmed that values obtained by the method was not affected by the molecular weight of γ-PGA. We demonstrated the formation of γ-PGA during manufacturing process of "natto" and its content of the commercial products by the method. γ-PGA was detected at 10h from the beginning of the fermentation and then increased. The mean value of the γ-PGA content and standard deviation in 34 commercial "natto" were 328mg±120.99 per 100g on wet basis.

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The essential oils of Ulva pertusa were prepared by steam distillation under the reduced pressure, and separated into 6 fractions through a silica-gal column (solvent: pentane/ether). Each fraction was analyzed by a capillary gas chromatograph-mass spectrometer (GC/MS). Sixty compounds were identified by the similarity of GC/MS fragment pattern and retention indices of individual aroma constituents. Eight sulphur containing compounds were detected by GC with a selective detector, flame photometric detector. As the characteristic aroma was smelled in fraction 1 and fraction 3, each component in both fractions was evaluated by GC-sniff test. Thirteen compounds such as dimethyl sulfide, β-ionone, 7-heptadecene and long chain aldehydes were selected as the characteristic aroma constituents of Ulva pertusa. Furthermore, as the important compounds, extra 4 compounds having odor unit value more than 1 were added as the important aroma compounds in Ulva pertusa. The mixture of 17 compounds prepared along with the GC peak area smelled like a seaweed but not real aroma of the algae.

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Tartary buckwheat (Fagopyrum tataricum), a species of edible buckwheats, is commonly taken as a diet in eastern Asian countries. Tartary buckwheat contains highly rutin, and has been found to lower one's blood pressure, but it's characteristic bitter taste prevents it from using as a diet in Japan. Therefore, in an attempt to use tartary buckwheat as a desirable food additive available for improving hypertension, the elimination of bitterness from tartary buckwheat flours was investigated. It was revealed through sensory analysis that bitter components which mainly located outside the grain could be extracted from tartary buckwheat flour with 75%(v/v) aqueous ethanol solution. As the bitter components, three compounds, quercetin, uncertain bitter compound F3 and F4 were isolated. These components were easily eliminated by washing the flour with 75%(v/v) aqueous ethanol solution. Furthermore, the production of quercetin and uncertain bitter compound F3 were prevented by heating the flour at more than 70°C. Because these treatments didn't decrease the rutin content, bitterness free tartary buckwheat flour obtained was expected to be useful for a material of physiologically functional food available for improving hypertension.

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The effects of water and sodium chloride added to dough on the microstructure and rheological properties of noodle were investigated. Gluten structures in the noodle were changed from fibrous network to spherical network surrounding starch granules with an increase of added water. The contrary phenomena was observed in the noodles with increasing sodium chloride. The noodles, prepared from dough providing relatively large and stable amplitude of torque during mixing, contained fibrous and continuous gluten structures. The tensile strength of the cooked noodle changed according to the combination of added water and sodium chloride. The noodles which contained the fibrous and continuous gluten structure showed high tensile strength. When backwards stepwise multiple regression analysis was applied to the tensile strength of cooked noodle, a significant correlation (P<0.01) was obtained between added water, sodium chloride and tensile strength.

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In order to clarify the relationships between the proteinase and the fruit-body growth and basidiospore formation in mushroom, we studied the proteinase in the fruit-body of Flammulina velutipes cultured in potato dextrose liquid medium, and following results were obtained. (1) Acid and neutral proteinase with optimum pHs of 3.2 and 6.5 was found in the fruit-body. Both the enzymes exhibited increased dramatically activities in the pileus (12 times) but did not show significant activities change in stipe during the fruit-body growth. When comparing the activities of both the enzymes, the total activity and specific activity of neutral proteinase was 4 times and 3.3 times greater than that of acid proteinase enzyme, respectively. (2) When treated with various types of proteinase inhibitors for elucidation the type of enzyme, it was observed that acid proteinase to be carboxyl type and neutral proteinase having metal type. The isoelectric point of the metal type enzyme was pH 6.0. From the above observations, it was concluded that the metal proteinase having pI 6.0 was important for the fruit-body growth and also exhibits significant role in basidiospore formation.

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We developed a novel enzymatic method for determination of curdlan in foods by using Bacillus curdlanolyticus sp. nov. β-1, 3-glucan glucanohydrolase (EC. 3.2.1.6.) capable of hydrolyzing resistant curdlan with formation of laminaribiose as the sole product. After curdlan was thoroughly hydrolyzed by the enzyme, the resulting laminaribiose was derivatized with 1-phenyl-3-methyl-5-pyrazolone (PMP). The PMP derivative was then analyzed by reverse phase partition chromatography on a column of Capcell pak C18 with a UV detector. The method, combined with the pretreatment procedures described by PROFSKY et al. for total dietay fiber analysis, was applied to the determination of curdlan in various foods such as momen tofu, kamaboko, pressed ham, hamburger, udon, Chinese noodle and processed cheese. The recovery of curdlan of not less than 94% was obtained for every food, except for hamburger. Thus the present method provides a specific and widely applicable analysis of curdlan in foods.

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Thermolysin-catalyzed enzymatic synthesis of N-(benzyloxycarbonyl)-L-aspartyl-L-phenyl-alanine methyl ester (ZAPM) which is an aspartame precursor was performed in organic solvent systems. Organic solvents were selected on the basis of the solubility of the substrates and the product; N-(benzyloxycarbonyl)-L-aspartic acid, L-phenylalanine methyl ester and ZAPM. Their solubilities depended upon log P values of solvents. Three reaction systems (system I: organic solvent mono-phasic system, system II: water saturated organic solvent mono-phasic system and system III: water/organic solvent bi-phasic system) were employed for the enzymatic reaction using selected solvents. Methoxyethanol and pyridine were newly found to be useful solvents for system I as well as tert-amyl alcohol and butyl acetate. Ethyl acetate, tert-amyl alcohol, butyl acetate and chloroform were suitable for system II and III. The efficiency of modification of enzyme surface using surfactants was examined in the organic solvent mono-phasic reaction system. An increase of the enzyme activity by the modification was observed in system I using chloroform.

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For the determination of residual sulfite in liquid foods by a microbial sensor method, the conditions for decomposition of combined sulfite into free form by sodium hydroxide and antioxidant were examined. The microbial sensor method was applicable to the determination of sulfite in beer by being made flat. The optimum antioxidant and the concentration was determined to be L-cysteine monohydrochloride and 4(w/v)%, respectively. Under the optimum conditions, the recovery of added sulfite from 7 kinds of liquid foods was 90.0 to 99.4%. For the determination of total sulfite, the reproducibility of this method was better than that of the modified Rankine's titration method. These results indicated that the microbial sensor method by alkaline hydrolysis treatment was applicable to the determination of residual sulfite in liquid foods.

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Aqueous solutions of several enzymes were exposed to supercritical carbon dioxide (SC-CO₂) at the condition of 10-20MPa and 35°C. The activity of oxidoreductases containing metals, eg. catalase, peroxidase and polyphenol oxidase reduced by SC-CO₂. The enzyme activities reduced with increasing time and pressure during the SC-CO₂ treatment. However, lipase and pyruvate decarboxylase hardly lost the activities by SC-CO₂. These results showed that there was a significant difference in the sensitivity of enzymes to SC-CO₂.

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The effects of a non-dialyzable extract of amaranth seeds on the immunoglobulin M (IgM) production and proliferation of a human-human hybridoma cell line, HF10B4, were examined. The extract of amaranth seeds promoted the IgM production of HF10B4 cells at concentrations ranging from 0.25mg/ml to 2.5mg/ml. The proliferation of HF10B4 cells was slightly activated at concentrations ranging from 0.007mg/ml to 0.01mg/ml. The IgM production-stimulating (IPS) activity of the extract remained after heating it at 40, 60 and 80°C for 20 min. The IPS activity of the extract was found to exist in the fractions with a molecular weight of over 30000 on Sephacryl S-100 HR column chromatography of the extract. On DEAE-Sepharose ion exchange chromatography of the active fraction, the IPS activity was found in both unadsorbed and adsorbed fractions.

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