Oolong tea is partially fired and then steamed, thus being intermediate between green and black teas. After being sorted on the basis of size, all grades of tea are packed in foil-lined chests to prevent the absorption of odors or the loss of aroma during shipment. Tea Composition, Consumption, and Polyphenol Chemistry T ea is grown in about 30 countries but is consumed worldwide, although at greatly varying levels. It is the most widely consumed beverage aside from water with a per capita worldwide consumption of approximately 0.12 liter per year. Tea is manufactured in three basic forms.
Green tea is prepared in such a way as to preclude the oxidation of green leaf polyphenols.
During black tea production oxidation is promoted so that most of these substances are oxidized. Oolong tea is a partially oxidized product. Green tea is consumed primarily in China, Japan, and a few countries in North Africa and the Middle East. Tea accumulates aluminum and manganese. In addition to the normal complement of plant cell enzymes, tea leaf contains an active polyphenol oxidase which catalyzes the aerobic oxidation of the catechins when the leaf cell structure is disrupted during black tea manufacture.