黒斑病甘藷の病理化学的研究 : (第11報)被害部隣接健全層の重曹水浸漬による緑変現象の機構(その2)

概要

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1. An experiment was done on the coloration of 33 different kinds of synthetic and natural polyphenolic substances oxidized by polyphenol oxidase and Purpureo Salz under the slightly alkaline condition. Caffeic acid esters, such as chlorogenic acid and methyl caffeate, and caffeyl amide turned into green, but caffeic acid, dihydrocaffeic acid and its esters, protoctechuic acid and its esters, 3, 4-dioxycinnamoyl ketone and caffeyl chloride etc. turned into brown or reddish brown. 2. The polyphenols, which into green, must have a sidechain of 3 or higher odd number of carbon atoms at the para position of a phenol ring. This chain is forming a conjugated double union together with a benzene ring, and it links, at the terminal, with a radical which has +E effect of a certain intensity. 3. The identification of each polyphenolic substance which in existing in many parts of a plant would be carried out by the following method (A) A sample was dipped in NaHC03 solution and heated. Or the exracting solution of the sample was mixed and heated with the solutions of NaHC03 and polyphenol oxidase or Purpureo Salz. (B) By the change of color or the solution, the kind of the substance could be identified. When it turned into green, caffeic acid ester would be present; when it was reddish brown, catechin or caffeic acid; and when it was brown, tannin.