Irradiation of Co-60 gamma-ray under a frozen state considerably inactivated Lactate Dehydrogenase (LDH). Peptide PA-50 (hydrolysed product of collagen) was found to have protective ability against the irradiation. From the mixture of LDH solution (1ml), 30% acrylamide+2.71% N, N'-methylenebisacrylamide (1ml), 30% magnesium acrylate (2ml), 30% sodium acrylate (1ml) and Peptide PA-50 (50mg), the immobilized LDH was prepared with good physical qualities and high enzyme activity. Immobilization shifted the optimum pH from 6.5 to 7.5, and improved the stability at acidic pH. The immobilized LDH was subjected to the one hour reaction repeatedly 20 times with activity loss of less than 20%. Determinations of ADP, glucose and Pyruvate Kinase activity were successfully performed by use of the immobilized LDH.

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In previous papers¹⁾²⁾, we have studied the cooking-rate of root vegetable slices. In order to design various cooking apparatuses, it is necessary to measure the thermal diffusivity which must be used for cooking of large root vegetables. In this paper, we studied the thermal diffusivity of the root vegetables curved spherically. The values of thermal diffusivity of popato, sweet potato, carrot and radish were obtained to be 0.097, 0.101, 0.103 and 0.101cmcm²/min, respectively.

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Crude green tea was heated at 130°C for 30min, and at 160°C for 30min. The analyses some ingredients indicated that amino acids, free reducing sugars and vitamin C contents decreased remarkably during heating, while caffeine and total nitrogen hardly decreased. Furthermore, by use of theanine, glucose, (-)-epicatechin and caffeine as model compounds, the interaction among them during heating was investigated. The results indicated that the interaction between theanine and glucose was observed remarkably, and that between theanine and (-)-epicatechin was observed a little.

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Bean sprouts were cultured by use of soybean (Glycine max), mung bean (Vigna radiata), and adzuki bean (Vigna angularis) as materials, and suitable harvest time was estimated by considering such factors as degrees of growth, hardness of hypocotyl, and nutritional constituents. Cultivation was conducted under the optimum condition reported in the previous paper; that is, the seeds stored for 6 months at 0°C were immersed in 30°C water for 6 hours and held on sprouting beds which were sprayed 30°C water for 15 minutes every 4 hours. The three kinds of bean sprouts grew up rapidly during 4-5 days after planting (before immersion), after that the hypocotyl showed a slight decrease in diameter and became yellowish. Elongation, too, stopped for a while and the formation of lateral roots and foliage leaves was found 7 days after. Hardness of hypocotyl also increased during first 5 days, then gradually decreased. General tendency of the changes of vitamin C (reduced ascorbic acid), protein, and fat during cultivation was almost similar among the three beans. Vitamin C was synthesized during sprouting and its content increased through 5 days after planting, then slightly decreased. The greater part of vitamin C was found in hypocotyl. While the change of protein content differed between in hypocotyl and in cotyledon, its total content in the bean sprouts decreased rapidly during 4-5 days after planting. Fat content also showed a rapid decrease in a similar manner. The contents of protein and fat were markedly higher in soybean sprouts than in mung bean and adzuki bean sprouts. By considering both external appearance and internal quality, it was concluded that 4-5 days after planting would be an optimum harvest time for three kinds of bean sprouts tested.

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Near infrared spectrophotometric technique was examined to confirm the feasibility of predicting some major compositions of wheat, soybean, pork and fresh potatoes. Two commercial types of instruments were used in order to check the characteristics by combining an in-house designed precise instrument simultaneously. It was concluded that the technique had a high potential for predicting protein of wheat and soybean, and fat and moisture of pork. As for sliced fresh potatoes, an electrical noise was rather too serious to derive good results. However, judging from the features of the second derivative of transmittance spectrum, it was possible to believe that there was a feasibility still assured for predicting the composition of potatoes.

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Eighteen kinds of developing solvents for the thin layer chromatographic separation of limonoids contained in seeds of Citrus Natsudaidai on a silica gel G plate were examined. It was demonstrated that the crude limonoids extracted from the seed were separated into six spots with nine kinds of solvents; chloroform-acetone (9:1), ethyl acetate-n-hexane (9:1), ethyl acetate-ethyl ether-n-hexane (5:4:1), methylenechloride-ethyl ether-acetic acid (185:15:2), benzene-chloroform-ethyl ether-acetic acid (8.5:8.5:3:1 and 13:13:13:1) and chloroform-ethyl ether-acetic acid (130:65:2, 26:13:1 and 30: 10:1). Both benzene-chloroform-ethyl ether-acetic acid (13:13:13:1) and chloroform-ethyl ether-acetic acid (130:65:2) systems were better than any other solvents.

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An ordinary frying process under atmospheric pressure brought about brownish discoloration or dried food making of potato, colored vegetable and fruits cut into thin slices. The authors found out that the discoloration was prevented when frying was carried out under reduced pressure and suggested that the maintenance of pressure at about 60mm Hg would be suitable for the treatment at 100°C for ten minutes.

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