Polyphenols in tea

Tea is the most widely consumed beverage in the world after water. The daily consumption is around 3 billion cups per day.

Regular intake of tea is associated with improved antioxidant status in vivo, which may contribute to lowering the risk of coronary heart disease, stroke, and certain type of cancers.

The polyphenols in tea mainly include the following six groups of compounds: flavonols, hydroxy-4-flavonols, anthocyanins, flavones, flavonols, and phenolic acids.

Among these, the flavonols mainly catechins are most important and occupy 60-80% of the total amount of polyphenols in tea.

The tea plant is known to contain seven kinds of major catechins and traces of various other catechin derivatives.

These catechins are present in all part of the tea plant; 15-30% are present in the tea shoots, and there is also a high content in the second and third leaves.

About 90-95% of the flavonols undergo enzymatic oxidation to products which are closely responsible for the characteristics color of tea infusion and its taste.

During the manufacturing of tea, the content of polyphenols increases slightly at the beginning of withering but decreases right after.

Although the trend for the changes of polyphenols appears similar in different varieties the absolute content of polyphenols are different among them.
Polyphenols in tea