Studies on the ‘fermentation’ of ceylon tea. X.—pectic enzymes in tea leaf

Fermenting tea leaf produces methanol as the result of enzymic demethylation of pectins contained in the leaf. The enzyme concerned (which was isolated and purified) is very similar to pectin‐methylesterases found in other plants. The activity of tea pectin‐methylesterase is partially inhibited by tea catechins and their oxidation products, but nevertheless a continuous demethylation process gives rise to pectic acid during the course of fermentation. In one particular case, a leaf mass exceptionally rich in pectin and pectase gave indications of gel formation. The significance of the pectic acid formed during tea ‘fermentation’ is discussed.