Effect of different withering temperature and humidity conditions on activity of PPO, POD and black tea polyphenols and pigments

By controlling different withering temperature and humidity, and then using better condition of rolling, fermentation, drying to make black tea and determined the activity of polyphenol oxidase ( PPO) and peroxidase ( POD) , the content of polyphenol and tea pigments. The research showed that PPO activity was significantly positively related to the wanter content of withering leaf during different temperature and humidity withering treatment, 70% withering humidity could process black tea with the highest content of theaflavins, the oxidation of tea polyphenols and the formation of tea pigment in black tea fermention had close relationship to PPO and POD, and the POD activity of withering leaf was significantly negatively correlated with theaflavins and thearubigins of black tea.