カキ果実のアルコール脱渋時におけるエタノール含量と脱渋及び追熟との関係

Abstract

In order to clarify the changes in fruit constituents, carbon dioxide and ethylene evolution, and other characteristics of persimmon fruits during de-astringency and ripening, experiments were conducted on fruits containing different concentrations of ethanol, ranging from 0.00% to 1.40% as obtained by various alcohol treatments.1. The higher the concentration of ethanol, the shorter the time to the beginning of decrease in tannin concentration and the more rapid the rate of decrease in tannin concentration. However, a lag period was found in the decrease in tannin concentration At 20°C this was about 2 days. Increased ethanol concentration had a marked influence at concentrations below about 0.2 to 0.3%.2. There was a higher acetaldehyde concentration with increasing ethanol concentration.3. Alcohol treatment caused a rise in ethylene evolution, the peak rate being higher with increasing ethanol vapor concentration. At 20°C it occurred about 1 day after tart of treatment. This high rate of ethylene evolution at 20°C induced a rise in arbon dioxide evolution and seemed to stimulate decreases in both flesh firmness and eel chlorophyll concentration.4. There was no significant difference in the rate of decrease in flesh firmness between alcohol-treated fruits containing less than 0.1 to 0.2% of ethanol and untreated fruits.5. The peel carotenoid concentration of alcohol-treated fruits containing 0.03 to 0.20% of ethanol increased at a similar or somewhat slower rate compared with that of ntreated fruits.6. No significant discoloration at the peel surface was observed in fruits containing less than about 0.1% of ethanol. Moderate to severe discoloration was observed in fruits containing more than about 0.1% of ethanol treated under excessive moisture conditions and in fruits containing more than about 0.3% of ethanol. Fruit exhibited a ore severe discoloration with a decrease in temperature at the time of alcohol reatment.7. Based on astringency removal and fruit quality, an adequate concentration of ethanol n fruit during de-astringency by ethanol was considered to be about 0.1 to 0.2% of thanol at 10°C to 20°C, and about 0.2% of ethanol at 30°C.