In order to establish a practical technique for extending the shelf-life of forcing-cultured 'Tonewase' persimmon fruit (Diospyros kaki Thunb.) by using perforated polyethylene packaging, the pattern of fruit softening at various storage temperature was investigated. Even under high storage temperature such as 35°C, the perforated polyethylene packaging significantly delayed the occurrence of softening and induction of C₂H₄ production through alleviation of water stress. In nonpackaging fruit, after CO₂ treatment, the induction of C₂H₄ production and fruit softening were observed during 3 days-deastringency period at 25°C. Thereafter, subsequent cold storage at 5°C could not effectively suppress the progress of fruit softening in spite of reduced C₂H₄ production and weight loss. Our results indicate that the perforated polyethylene packaging is a useful technique to extend shelf-life of 'Tonewase' persimmon fruit marketed even during summer season and it can not be replaced by low temperature preservation.

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Two potato cultivars, Toyoshiro and Norin-ichigo, which are commonly used in Japan for processing, were stored at 7 t for 3 months, and the sugar (glucose, fructose and sucrose) and starch contents within the potatoes were measured at intervals during storage. The aim of this study was to examine sugar distribution within the potatoes. Regarding reducing sugar (glucose + fructose) or starch contents, a linear relationship was found between that in stem and bud areas of both processing potatoes ; the significant (p< 0. 01) relations indicated that the stem end of both cultivars had 2. 5 and 1. 1 times higher reducing sugar and starch contents, respectively than the bud end during storage.

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Aspergillus oryzae N-1 and N-4 were isolated from ina-koji. Those isolates produced citric acid 4 times much as Aspergillus oryzae RIB-176, using sake making, in rice koji. Using the rice koji of 40% moisture, A. oryzae N-1 produced a great deal of citric acid in polished rice of 73.8% at 32°C and A. oryzae N-4 in polished rice of 53.6% at 37°C.

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The contents and composition of sugars, acids and pectic substances were compared between 5 varieties of european pear. Total sugar contents at harvest time are 9 to 11% in “Bartlett”, “La France” and “Passe Crassan”, and those in “Winter Nelis” after 40 days cold storage and in “Doyenne du Cornice” after 60 days cold storage are 12% and 11% respectively. Main sugar components are sucrose, glucose, fructose and sorbitol in all varieties investigated here. Fructose is most dominant sugar, this ratio to total sugar content occupied 60-70% in “Bartlett”, “La France” and 81-85% in other three varieties. Free acid content at harvest time are 0. 3-0. 4% in “Bartlett” and about 0.2-0.3% in other varieties. The dominant acid is citric acid in “Bartlett” alone, and malic acid in other varieties. Total pectic substances content at harvest time were about 400mg per 100 g of fresh fruit in “Bartlett”, 500-600mg in “Passe Crassan” and 470-690mg in “La France” respectively. Water-soluble ratio to total pectin content was about 20%, sodium hexameta-phosphate-soluble ratio about 10%, and NaOH-soluble ratio about 70%. Water soluble ratio increased to more than 60% with after-ripening, NaOH-soluble ratio decreased to 20-30% in the stage of ripeness suitable for eating.

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