In the process of sterilizing Bacillus subtilis spores under UV light, a linear correlation was observed between the logarithm of the number of surviving spores and the UV exposure time. When UV was used solely to sterilize them, Decimal reduction time (D value) was 3.3 sec at 3.6mW/cm² and 2.2 sec at 20mW/cm². It decreased, however, to 2.1 sec and0.6 sec respectively, when UV was applied after the suspension of B. subtilis spores had been treated by heat for one min at 90°C. Irradiation of UV to the suspension of spores withan organic acid was effective to lower D value. Used with UV at 20mW/cm², acetic acid had the strongest effect among several organic acids reducing the value to around 0.2-0.3 sec ateach level of 0.1M, 0.5M or 0.0lM. In addition, when UV was applied at 3.6mW/cm², a linear correlation (α=5%) was observed between pH of four kinds of organic acids (1.8-3.2) and D values. Consequently, in order to increase the effect of UV on B. subtilis spores which are resistant to UV, UV should be applied together with heat or organic acids. Sterilizing effect was strengthened further in the case of UV appliance after heat treatment in an organic acid solution. On the other hand, there was no effect on Aspergillus when heat or an organic acid was used with UV.

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We previously reported a method for predicting the optimum cooking time of potatoes during cooking. In this study, we tried to apply the previous method to other eleven species of vegetable samples. The rate of softening of vegetables was approximated by a first order kinetics except the case of eggplant, and the rate constants were obtained from the hardness value measured by a Texturometer. The rete constants at 99.5°C of ten vegetables, namely, sweet potato, potato, taro, squash, pumpkin, Japanese radish, turnip, carrot, asparagus, and edible burdock, were 0.204-1.053 (min^-1) except 0.023 (min^-1) of edible burdock. Vegetables containing starch seemed to have the higher rate constants than others except turnip. The range of the optimum softening ratio was 0.65-0.98, except 0.22 of edible burdock, and the ratio of higher starch content vegetables was almost 1.00. The optimum cooking time of small piece samples at 99.5°C, calculated from the rate constant and the softening ratio, ranged from 1.3min of turnip to 10.5min of edible burdock. Vegetable samples cooked for calculated the optimum cooking time were judged to be cooked properly by sensory panel members. From these results, we suggested that we could apply this method to ten species of vegetables.

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The stability of α-tocophero1 (α-Toc) and antioxidative effect of δ-tocopherol (δ-Toc) in cookies, were studied. (1) α-Toc was decomposed by about 20-30% during baking cookies. This decrease was not related to the added amount of α-Toc. Peroxide value (PV) of the lipid fraction of baked cookies increased with an increase in the added amount of α-Toc. However, the value was lowered with an increase in the added amount of δ-Toc. (2) The loss of α-Toc in cookies during storage became higher with an increase in the added amount of α-Toc, and this decrease was not protected with an increase in the added amount of δ-Toc. PV of the lipid fraction in the cookies rose with an increase in the added amount of α-Toc during storage. However, a rise of the value was reduced with an increase in the added amount of δ-Toc.

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The matrix reconstructability of three kinds of pepsin-solubilized collagen prepared frompig skin insoluble collagen by repeating pepsin-digestion three times was remarkablydepressed in order of the frequency of pepsin-digestion as compared with that of acid solublecollagen. DSC (differential scanning calorimetry) curves of the reconstructed matricesindicated that these matrices had somewhat lower thermal structural-stability than that ofacid soluble collagen. These pepsin-solubilizedacid collagens were reconstructed to matriceswith various thermal stability under the different conditions upon reconstruction. Fromthese results, it is suggested that the matrix reconstructability of pepsin-solubilized collagenand the thermal structural-stability of the matrix can be regulated by controlling the extentof pepsin-digestion and the conditions of reconstruction medium.

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A simple method was developed for determining rutin in buckwheat flour by highperformance liquid chromatography (HPLC). Rutin was extracted with hot methanol and separated by HPLC on a column packed with Nucleosil 7C₁₈(NAGEL) by using 2.5% acetic acid, methanol and acetonitrile (35:5:10) as a mobile phase and detector set at 350nm.With this method, amounts of rutin in commercial buckwheat flours and buckwheet foods were determined. There were differences in the amounts of rutin among different species of buckwheat (12-22mg/100g). And remarkable differrences existed in buckwheat flours were determined. There were differences in the amounts of rutin among different species of buckwheat (12-22mg/100g). And remarkable differrences existed in buckwheat flours processed in a gradual milling system (4-33mg/100g). The amount of rutin was low in roasted buckwheat grain (soba-tea) or steamed buckwheat grain (soba-mai), but rutin was rather stable with sterilization by super heated steam or γ-ray irradiation. The amounts of rutin in commercial buckwheat noodles (made from buckwheat and wheat flour-water dough and sold in raw or dried state) were from 1 to 15mg/100g. It was confirmed that rutin in buckwheat noodles decreased as cooking-time increased.

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For the quantitative determination of buckwheat flour contained in buckwheat foods, rutin analysis was applied. As to the mixture of buckwheat and wheat flours, it was possible to estimate the concentration of buckwheat flour by rutin analysis. But in the case of buckwheat noodles (made from buckwheat and wheat flour-water dough), the estimation was not necessarily accurate. Because in the processing or preserving of buckwheat noodles, the amount of rutin partially dicreased in course of time. And this phenomenon was estimated to be due to the enzymatic degradation of rutin. The rate of decrase was innuenced by the amount of water added to the buckwheat and wheat flours. The decrease was not observed in buckwheat flour sterilized by super heated steam, but was observed in buckwheat flour sterilized by γ-ray irradiation. The decrease of rutin and the increase of quercetin were confirmed in a HPLC pattern. Rutin degrading activity was high in the embryo and "amakawa" fraction (rich in pericarp of dehulled grain). The enzymatic activity in water extract of buckwheat flour was deactivated by heating to 60°C, for 15 min.

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The relationship between browning level and formation of furfural (FUR) and 5hydroxymethylfurfural (HMF) in stored yuzu (Citrus junos Tanaka) juice was examined.Since there was a highly significant correlation (r=0.9995) between the concentration ofascorbic acid (AA) and the level of FUR, it was confirmed that FUR in the stored juice wasformed by the non-oxidative degradation of AA to a considerable extent. The regressionline between browning level and the concentration of AA implicated the presence of anadditional factor on browning other than AA. From the experiments on the juice and anAA standard solution, it was indicated that both FUR and HMF would not be the causalfactors of browning, and that the intense browning would be arised from dehydroascorbicacid (DHA). It was suggested, therefore, that both pathways from AA to FUR and to DHAproceed simultaneously in the stored yuzu juice, and that the latter was a main pathway for browning.

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In Japan, soybean seeds are used to make Nimame by cooking them with sugar and salt syrup. Since the quality of Nimame is mainly affected by that of raw soybean seeds, the good quality seeds are required for Nimame processing. In this paper, the seeds of 4 cultivars cultivated at 2 locations were used to evaluate their suitability for Nimame. The items for examination were chemical constituents (moisture, protein, oil, total sugar, free sugar, and total carotenoid contents) and suitability for Nimame processing (weight of 100 seeds, weight increase ratio of soaked seeds, germination ratio, solid matter content in soaked water, weight increase ratio of soaked seeds by steaming, softness, appearance, and color of boiled beans). Sensory quality of Nimame and its change in color by storage were also tested. The characteristic chemical compositions observed were high free susugar andtotal carotenoid contents in Otsuru, low protein and high oil and free sugar contents in Tamahomare, and low free sugar and total carotenoid contents in Enrei. Otsuru had a largeseed size, a low germination ratio, and a high content of solid matter in soaked water of the seeds and the low coefficient of variation (CV) of hardness, low a and high b in the color values in boiled beans. Many swelled husks were observed in the boiled beans of Enrei. In the sensory test of Nimame, Otsuru was highly rated in appearance, taste, hardness, color, and overall evaluation. Tamahomare was appraised low in hardness, but the highest in color. From those results, it was presumed that the large seed size, a low CV value of hardness, and a high color value of b in boiled beans were the most important factors affecting the quality of Nimame. In the storage test of Nimame at 30°C in a polypropylene bag for 7, 14, 21, and 28 days, color damage was high in Enrei, but low in Tamahomare. The b value reduced rapidly in Otsuru.

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The analysis of residual EDB (ethylene dibromide) in the imported fruits using the Dean-Stark apparatus and ECD-GC was investigated and the following results were obtained: (1) The recovery of EDB was more than 98% by the proposed method. (2) EDB content in mango pulps decreased with the storage time at room temperature (25°C) or in refrigerator (7°C), but the content did not decrease for 6 days by the storage in freezer (-20°C). (3) There were considerable variations in EDB content in mango pulps by the sampling method. (4) The bigger the mango, the higher the residual EDB concentra tion was. (5) EDB content was higher in seeds than in pulps or peels. We also surveyed the concentration of residual EDB in pulps, peels and seeds of the imported fresh fruits (grapefruits, papayas, mangos and litchis) purchased at the fruits-shop in Osaka Prefecture in April to June, 1987.

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According to the progress of the technique of GC analysis, Kovats Retention Index (KI) together with GC/MS analysis has become more important for the identification of volatile compounds. In this paper, a new method for the calculation of KI values has been reported. Based on known compounds, KI values of the components of a chromatogram were calculated without using n-paraffins as reference compounds. This calculation program of KI values was applied to the volatile compounds of oxygenated fraction of Shiroyanagi navel oil and gave good reliability.

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Studies on the effect of the addition of plant and animal protein sources to fish mixture for the modification of aroma of fish sauce were carried out. Chicken liver and soybean protein were added to fish, incubated and the supernatant liquid was analyzed by gas chromatography and gas chromatography-mass spectrometry. It was observed that fish sauce mixture with chicken liver gave a little sweet aroma and less rancid than the original fish sauce. Mixtures of fish and chicken liver gave a little change in the total aroma and could be acceptable as an alternative if not exactly as a substitute. Soybean protein did not reveal its characteristic odor when analyzed under the same condition with the chicken liver added fish mixture and could be added in the fish sauce production without affecting the total aroma of fish sauce.

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