During the processing of black tea, a chemical reaction centered on the oxidation of tea polyphenols occurred. The chemical
composition in the fresh leaves changed greatly, and the tea polyphenols were reduced by more than 90%, resulting in the production of new components such as theaflutein and Thearubigins. Aromatic substances were significantly increased than fresh leaves.Therefore, black tea has the characteristics of black tea, red soup, red leaves and sweet and mellow taste.