Tea contains several chemical constituents, but polyphenols (polyphenols) are the most essential in determining the color and flavor of tea.<br />Black tea is frequently made by completely oxidizing tea leaves before drying them. Catechins, a flavonoid family of compounds, make about 27 percent of the non-oxidized components in green tea leaves, but their amount is decreased to roughly 4% in black tea due to the oxidation process.<br />Polyphenols are the oxidation products of catechins in black tea, and they alter both the taste and color of the tea. The polyphenols found in black tea come in a variety of shapes and sizes. Theaflavins are one of the most well-known of these compounds, while thearubigens are a broad category of polymeric polyphenols.<br /><br /><br />MSc Salam Mohammed Naser