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
Black tea tea is a blend of two or more black teas of the leaves and buds of "Camellia sinensis" that contain at least 30 percent water-soluble extractive, with 4 to 7 percent ash. Unblended black tea contains at least 25 percent water-soluble extractive, with 4 to 7 percent ash. Packaging of black tea is based on the packaging guidelines from the country of origin. Generally, unblended black teas are named after the region in which they are produced. Often, different regions are known for producing teas with characteristic flavors. Black tea is often blended and mixed with various other plants in