Tea Manufacture in C. R. Harler Way The Chemistry of Black Tea Manufacture and the Pharmacology of tea

摘要

The action of the oxidase on /-epi gallo catechin and its gallate, and perhaps other members of the catechin group occurring in tea leaf, is to oxidize them to ortho-quinones. Here the enzyme action ceases, and the reactions that follow are not enzymic. The ortho-quinones dimerize to bisflavanols and theaflavins. Three of the former and two of the latter have been identified. These yellow bodies dimerize further to form thearubighis which are red and brown bodies. Correct tea manufacture aims at getting a suitable ratio of theaflavins to thearubigins. Spectrophotometric measurements of these two groups of bodies have been made, and it is possible that such may serve as a basis for the chemical evaluation of the market value oftea.