We investigated the method of low oxygen treatment for prolonging shelf life of ripening-initiated banana cv. Sucrier, which were ripened until stage 3 (more green than yellow). Controlled atmosphere condition of 5% oxygen and nitrogen-gas application for 48h followed air stream extended shelf life of the banana only 1-2 days longer than control (continuous air flow, 3-4 days shelf life). Nitrogen-gas packing for 24 or 48h in polyethylene (PE) bag (0.03 mm thickness) extended the shelf life in cardboard box at 20°C to 5-6 days compared with 3-4 days in the control (air packing) although accumulation of the sugar content of banana was same as control. A 24h nitrogengas packing in PE bag and then polyvinyl chloride wrapping extended the shelf life of banana to 9-11 days

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Invertase, sucrose-6-phosphate synthase (SPS) and UDP-glucose pyrophosphorylase (UGPase) activities of three Japanese processing varieties, differing in susceptibility to low temperature sweetening (susceptibile : Norin-1; middle : Toyoshiro; resistant : Hokkai-82), were measured at intervals during storage at 7°C in order to investigate the role of the three enzyme activities in reducing sugar accumulation during storage. The susceptible variety dramatically increased the reducing sugar content, and invertase, SPS and UGPase activities during storage, whereas the mid-susceptible and resistant varieties progressively increased them. In the three enzymes, both invertase and SPS activities correlated significantly (p<0.01) with the reducing sugar content, implying that invertase and SPS may play an important role in the regulation of the reducing sugar accumulation of processing potatoes stored at low temperature. This information may be useful for potato breeders to develop new resistant processing varieties.

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An alternate weekly spray application of electrolyzed acidic water and alkaline water on leaf surfaces of leeks in solution culture reduced bacterial counts at harvest by about 1.0 log for total viable bacteria and about 1.5 log for coliform group as compared with the control lot using the conventional cultivation method. In the examination of the growth conditions at harvest, the alternate spray lot showed significant increase in fresh weight without any acidic burns. These results suggested that the alternate weekly spray application of acidic water and alkaline water on leaf surfaces in solution culture is an effective treatment for both microbial safety and growth promotion in agricultural production.

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Acid phosphatase isozymes of 20 varieties of potato were analyzed by polyacrylamido gel electrophoresis and activity staining in order to investigate the relationship between isozyme and properties on potato. They were classified into four groups by isozyme patterns, and there were varietal differences in acid phosphatase activities. Moreover, isozyme patterns were difference between varieties used as food and processing materials or starch materials. It was suggested that an isozyme analysis could be utilized the classification on each purpose of potato.

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The partial seal packaging, which is a new type of modified atmosphere packaging (MAP), was applied to Welsh onions to study a practical distribution method. Judged from the score of leaf tip withering and off-flavor, a form with the width of 3 mm oblique sealed lane, the width of 7.6mm oblique fused part, and the width of 2.4mm oblique non-fused part was suitable for the partial seal packaging of Welsh onions. In a simulation test using a 100-g bundle of Welsh onions packed in a 25-μm-thick OPP bag of 85mm× 680mm for distribution in summer, a new distribution method in which partial seal packaging and cardboard container are combined kept oxygen low and carbon dioxide high in bags and suppressed the occurrence of the score of leaf tip withering markedly, comparing with the current method in which perforation packaging and styrofoam are combined. In addition, the contents of sugars and ascorbic acid of Welsh onions packed with the partial seal packaging were kept more than those with current packaging. The partial seal packaging was finely adjustable on the gas permeability of bags and applicable to fruits and vegetables other than Chinese chives by changing the sealing pattern of partial seal packaging.

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