Phenolic content in tea green tea. Catechins constitute about 25% of the dry mass of a fresh tea leaf, although total catechin content varies widely depending on species, clonal variation, growing location, season, light variation, and altitude. They are present in nearly all teas made from "Camellia sinensis", including white tea, green tea, black tea and oolong tea. Of all the catechins in tea, EGCG is the main subject of scientific study with regard to its potential health effects. 4-Hydroxybenzoic acid, 3,4-dihydroxybenzoic acid (protocatechuic acid), 3-methoxy-4-hydroxy-hippuric acid and 3-methoxy-4-hydroxybenzoic acid (vanillic acid) are the main catechins metabolites found in humans after consumption of green
Tea processing Tea processing Tea processing is the method in which the leaves from the tea plant "Camellia sinensis" are transformed into the dried leaves for brewing tea. The categories of tea are distinguished by the processing they undergo. In its most general form, tea processing involves different manners and degree of oxidation of the leaves, stopping the oxidation, forming the tea and drying it. The innate flavour of the dried tea leaves is determined by the type of cultivar of the tea bush, the quality of the plucked tea leaves, and the manner and quality of the production processing they undergo.