Effects of High Voltage Pulsed Electric Field on Antioxidant Activity of Tea Polyphenols for Yunnan Pu’er Tea

Abstract

In order to improve the antioxidant activity of Pu’er tea, the authors use different high voltage pulsed electric field (HPEF) to deal with the third grade Pu’er ripe tea, extract the tea polyphenols and determine antioxidant activity of tea polyphenols in each tea samples by four indexes, namely the ability of scavenging hydroxyl radical (·OH), the ability of scavenging superoxide anion (O2·–), the ability of scavenging radical DPPH and total reducibility. Then antioxidant activity of tea polyphenols is analyzed by stepwise regression analysis on Matlab, establish the mathematical model of its antioxidant activity and voltage, frequency. The results show that HPEF could decrease the content of tea polyphenols in Pu’er ripe tea, and promote it to translate into Theabrownines (TBs) and so on. The suitable conditions of HPEF can improve the antioxidant activity of Pu’er tea to a certain extent. This study provides a new physical method for improving the antioxidant activity of Pu’er tea polyphenols, and provides technical support for the extraction and development of natural antioxidants in Pu’er tea.