茶タンニンの各フラクションの酵素酸化について

概要

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The polyphenol-cathechol fraction of the tea leaf does not undergo auto-oxidation by means of atmospheric oxygen. This fration is however, intensively oxidized by the polyphenoloxidase, forming purple-red products of oxidation.<BR>The tea tannin, which had been freed of ether-soluble fractions, i.e. of polyphenols and cathechols, already undergoes intense auto-oxidation during the isolation of the preparation. Tea tannin is oxidized not only by auto-oxidation, but by polyphenoloxidase, also forming dark brown products of oxidation.<BR>It has been shown in model experiments, that during the enzymatic oxidation of different fractions of tea tannin, in addition to the coloured, soluble products, non-soluble products are formed, which are adsorbed on the fermentative preparations and colour them.<BR>It has been found that tea tannin is formed by an oxidative way, and the low-molecular fractions of tea tanning substances … polyphenols and cathechols … serve as a material for its building.