Progress in catechins oxidation products and their formation mechanism

: Catechins are the key components of tea and have a great impact on its quality. Catechins can be oxidized to form a new black tea polyphenols, some of which have better pharmacological effect. However, the formation mechanism of these new polyphenols is still unclear. In this paper, oxidation products coming from catechins and the formation mechanism of the new compounds are reviewed.It is the base of further study on theaflavins, thearubigins and theabrownines.