柿及小柿の葉のビタミンCについて

概要

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It has been said that the juice from the leaves of Kaki (japanese persimmon) boiled with water contains a large amount of vitamine C (l-ascorbic acid). But the measurement of vitamine C in the leaves of Kaki has not been carried out and the results have not been found in literatures. The present paper dealed with the contents of vitamine C in the leaves of Kaki by the indophenol method using 2,6-dichlorophenol indophenol-Na and the hydrazine method using 2,4-dinitrophenyl hydrazine. Mixture of 2 g. of the sample and 100 ml. of 2.5% HPO₃ was strongly homogenized for 2 min. in mixer and filtered by glass-filter (17G₂). Vitamine C in the filtrate was measured by the indophenol method, and it in the filtrate diluted with 9 volumes of 5% HPO₃ was done by the hydrazine method. From the experiment, it was made sure that the leaves of Kaki contained a large amount of vitamine C (500-1100 mg. per 100 g. of leaves) and the content was varied according to the variation of seasons ; the maximum content was about 1100 mg. or more per 100 g. of leaves in July and August. The contents of vitamine C in the leaves dried by various methods (natural drying, ultra-red ray heating and freezing vacuum drying) were also measured.
1969-02-28