Relationship between invertase activity and sugar composition of non-astringent persimmon 'Fuyu' and astringent persimmon 'Koshu Hyakume' was investigated. (1) When the persimmons were homogenized sucrose in 'Fuyu' was completely hydrolyzed to glucose and fructose for 20min at 30°C, while in 'Kosyu Hyakume' it was hydrolyzed for 10min at 45°C. (2) Optimum pH and temperature of invertase was about 5.0 and 45-50°C for both of the persimmons. (3) The Km values for 'Fuyu' and 'Koshu Hyakume' persimmons were 7.85mM and 2.25mM respectively. (4) Invertase activity of 'Fuyu' persimmon was considerably lower than that in the astringent persimmons, i.e. 'Koshu Hyakume', 'Hachiya', 'Ebo', 'Mizugaki' 'Kairyoshibu' and 'Yamato Hyakume'. Whereas the ratio of sucrose content to total sugar content of 'Fuyu' was higher than that of the astringent persimmons. (5) Among the six astringent persimmons, the ratio of sucrose content to total sugar content was not related to the enzyme activity. (6) In 'Fuyu' persimmon invertase acti ity did not change during maturation but increased during storage at room temperature. The ratio of sucrose content to total sugar content decreased gradually during maturation and storage.

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Physical, chemical and organoleptic properties of the shredded lettuce (5×5cm) prepared under various conditions were investigated during storage at 5 and 10°C. In processing conditions, a sharp blade slicing or a rotary cutting were superior to either a dull blade slicing or chopping. The shredded lettuce washed with flowing or air-bubbling waters gave 10^-1-10^-2 bacteria number and retained longer storage life than that washed with dipping into water. Chemical treatments such as ascorbic acid and sodium hypochlorite were ineffective. The centrifugal dehydration at 1000rpm for 30 seconds was beneficial. The orientated nylon/low density polyethelene pouch (60μm; ON/PE 60) vacuum-packed at 150mmHg suppressed the browning reaction and/or the ferment-like off flavor formation, which extended storage life of the shredded lettuce. The amounts of ascorbic acid, chlorophill, glucose and fructose and penetrating resistance of the shredded lettuce gradually decreased while the polyphenol content markedly increased after a week during storage. Ethyl alcohol was produced at 2-3% oxygen concentration in the headspace of pouch. The ethyl alcohol content significantly corresponded to the organolep- tic quality during storage. From these results, the preferable processing and storage conditions were developed as follows: slicing with a Sharp blade; washing with cold (5-8°C) and flowing water; dehydrating by the basket-type centrifuge (φ52cm, 1000rpm) for 30 seconds; vacuum-packing at 150mmHg into ON/PE 60 pouch; storing and distributing at 1-5°C.

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In order to know the effects of some organic acids on the quality of sunki-pickles, we tried to prepare Sunki-pickles not only by adding dried sunki as a source of lactic acid bacteria, but also by adding several organic acids, i.e. succinic, malic and oxalacetic acids, to non-pasteurized and UV-irradiated leaves of Ohtaki-turnip. The following results were obtained by microbiological survey, chemical analysis and sensory test of experimental products; (1) Though the main lactic acid bacteria in dried sunki were Lactobacilli, Leuconostocs were found in the products with addition of succinic acid and oxalacetic acid, and Pediococci were found in the product with addition of malic acid. These bacteria may be brought from the raw materials. (2) Small quantity of Leuconostocs were found also in the product prepared from UV-irradiated leaves, probably indicating insufficient sterilization. (3) The taste of sunki-pickles depends on the amounts of tasty amino acids and the kind of organic acids but not on the total amounts of amino acids. (4) Formation of aspartic acid from alanine and oxalacetic acid by transamination was not observed in this study.

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Relation between sugar content of potato tubers (Solanum tuberosum L. cvs. May Qween and Danshaku) and chip colour was investigeted using potato chips which were prepared after being stored at 1°C to 20°C. (1) Sugar content in potato tubers tended to increase during storage at temperature below 7.5°C for 40 days in both cultivars. No significant increase of sugar content was found in the potato tubers stored at 15°C and 20°C. (2) The slices of potatoes stored at temperatures ranging 1°C to 7.5°C turned brown during and after frying in fresh salad oil at 170°-180°C for 90 seconds. (3) A relatively close orrelationship was found between L values (Hunter's) of powdered fried chips and sugar ontent in stored potato tubers. (4) The simple correlation coefficients between reducing sugar content and L values were -0.836 and -0.841 and the correlation coefficients between the content of total sugar and L values were -0.791 and -0.780 in the potato chips from 'May Qween' and 'Danshaku', respectively.

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The mechanical textural characteristics of 5 trial gum bases and 13 trial chewing gums were comparatively analyzed with the purpose of establishing an objective evaluation method for chewing gum, and we tried the scanning electron microscopic observation of microstructures of chewing gums. Then the textural outlines of gum base and chewing gum could be grasped at apparent viscosity by flowtester and viscoelasticity by dynamic apparatus. The hardness of gum bases increased in propotion to natural resin contents, but the apparent viscosity decreased when the contents were 25-75%. The dynamic viscoelasticity of masticated chewing gums was dependent on the kind of gum bases and saccharides.

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Defatted soy flour (DSF:NSI ca. 35; crude prote in 55w/w%) was extruded three times to investigate the effects of longer residence time and shearing on the strength, fine structure and protein component of extrudates. The extruder used in this study was twin-screw, fully intermeshing type (Mitsubishi FT-60, L/D=20) equipped with a long cooling die and operated at 60rpm, 20kg/hr feed rate within 130-150°C. DSF was moistured to 60% and adjusted its pH to 7 with NaOH. The exturdates could be prepared without any puffing and found to have its apparent residence time 2.5min by the color distribution method. The major factor for DSF texturization was found to be the temperature and its critical value as around at 140°C, which agreed well with DSC of DSF. The repetition of extursion did ot disturb or destroy the protein matrix in the extrudate but improved or reproduced it, indicating that second factor was the residence time. Even after three times of extrusion cooking at highest temperature (150°C), the extrudates showed negligible loss of amino acids. These results suggested that DSF could be processed like the thermoplastic resin.

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It is known that chilling injury showing internal breakdown occurs in the pulp of Starking Delicious apples during cold storage, whereas the injury scarcely occurs in the Ralls Janet apples in Japan. The phosphatidylcholine (PC) and the phosphatidylethanolamine (PE) extracted from both cultivars were treated with phospholipase A₂. The fatty acid composition at 1-position, 2-position and overall position of PC and PE were examined by gas-liquid-chromatography, especially considering the ratio of unsaturated fatty acids which contribute to the fluidity and flexibility of membranes. As the results, the following facts became apparent. (1) In both cultivars, the fatty acids at 1-position were mainly saturated fatty acids and the fatty acids at 2-position were mainly unsaturated fatty acids. (2) The difference of the ratio of unsaturated fatty acids to total fatty acids was slight in the PC of both cultivars just after the harvest. The ratio of unsaturated fatty acids at 2-position of PE in Ralls Janet was larger than that in Starking Delicious. (3) After six-seven months of cold storage, the ratio of unsaturated fatty acids of both cultivars decreased slightly. The unsaturated fatty acids of 2-position of PE disappeared completely. (4) The ratio of unsaturated fatty acids at 2-position in Ralls Janet decreased largely after eight months of cold storage.

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Changes in volatile components of 9 spices usually used for curry making by heating at 120°C were investigated by gas-liquid chromatography. (1) Amounts of main volatile components in cardamon, clove and cumin were increased, total volatile components of them were also increased by the heat treatment. (2) Amounts of total volatile components in allspice and mace were decreased by heating slightly. (3) In funnel, cinamon and fenugreek, total volatile components were decreased by heating, especially remarkable in fenugreek. (4) Volatile components in spices were increased or decreased by the heat treatment, low volatile components were decreased in every samples. So, it is necessary to take notice of their changes for good flavoured curry making.

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The influence of gluten content in flour on the qualities of cookies was investigated. By the use of flour containing 4 levels of gluten (0%, 4%, 8%, 12%), cookies were prepared with the ingredient ratio of 45% flour, 26% butter, 21% sugar and 8% egg. The hardness of dough, and the rate of apparent expansion, the rate of water absorption, the apparent fracture parameters and the Hunter's color scale of the cookies were measured and these cookies were also evaluated by sensory test. The results obtained were as follows: (1) With the increase of gluten content in flour from 0% to 4%, 8% and 12%, the hardness of dough, and the apparent fracture stress and energy of cookies increased, while their lightness of color and the rate of apparent expansion decreased. (2) In the sensory evaluation, cookies with a lower level of gluten showed a lighter, softer, more brittle, better disintegration in mouth and more sweetness. (3) In the relation between the physical and the sensory parameters, there was a good correspondence between the Hunter's color and the score of color, between the apparent fracture stress and the hardness, between the apparent fracture energy and the shortness, and between the rate of apparent expansion or water absorption and the disintegration in mouth, respectively.

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A method for determinating the mixing ratios of sweet potato and kuzu starches in commercial samples was investigated. In X-ray diffraction analysis, the ratio could be estimated by measuring the ratio of diffraction intensity at 2θ 16.85° (4a) and 17.7° (4b). These partially overlapped 4th X-ray diffraction lines of kuzu and sweet potato starches were able to separate them into the 2 normal distribution curves. In thickening analysis with alkali, starch was thickened by mixing with potassium hydroxide solution in a test tube and after 20min it was observed whether the content moved or not in 5 sec by turning the test tube up-side down. The values of six commercial kuzu starches by the two methods described above coincided well with those by the three methods reported previously, i.e. scanning electron microscopy, light blocking and sedimentation.

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