Black tea is a type of tea that is more oxidized than oolong, green and white teas. All four types are made from leaves of the shrub Camellia sinensis. Black tea is generally stronger in flavor than the less oxidized teas.
During the processing of Tea, fully fermenting results in Black Tea. In the making of Black Tea, fermentation promotes the oxidation of polyphenols,which will produce thearubigin and theaflavin. They are the key factors that form the color and flavor of Black Tea. Beside of adjusting the color of tea liquid, thearubigin has many health benefits. It can combine with cholesterol in stomach and intestines, and reduce the amount of cholesterol absorbed from food. Thus thearubigin is helpful for protecting your heart from hyperlipidemia and heart disease without any side-effect.
Both green tea and black tea come from the leaves of the plant Camellia Sinensis, however the processing that the leaves undergo to make the final tea is different. The leaves for black tea are fully oxidised while those for green teas are lightly steamed before being dried.
Flavonoid content of black and green teas:
Black and green teas both contain similar amount of flavonoids however they differ in their chemical structure. Green teas contain more of the simple flavonoids called Catechins, while the oxidisation that the leaves undergo to make black tea converts these simple flavonoids to the more complex varieties called Theaflavins and Thearubigins.