Abstract:

Objective: To compare the tea polyphenols(TPs) content and antioxidant activity in different processed Chinese teas.
Methods: The TPs was extracted with 95% ethanol though ultrasonic after crushing. The content was determined by spectrophotometry
at the wavelength of 765 nm using Folin-Ciocalteu as the chromogenic agent and gallic acid as the reference. The antioxidant activity
was also tested by UV spectrophotometry though adding the Fe3+ ion as the oxidant. Results: The sequence of content of TPs and its
antioxidant activity were consistency. Green teas and the not fermented teas contained the highest TPs and had the most powerful
reducing capacity. While the fermented teas such as red teas and black teas had the lower polyphenols and antioxidant activity.
Conclusion: The content of TPs is negatively related with the fermented degree of teas and the antioxidant activity shows a good dose
effect relationship with the TPs.

Key words: teas, tea polyphenols, content determination, antioxidant activity