Study on ripening process of Pu’er fermented tea by high voltage pulsed electric field technique

CHEN TING, ZHAO YAN, WANG LAN, HE JI-YAN, PENG WEN, HU DING-YU, WANG BAI-JUAN*

*Corresponding author

Yunnan Agricultural University, Yunnan Kunming 650201, China

Abstract

A special storage way that Yunnan Pu’er ripe tea is more and more popular for its aroma and taste palate with the increasing of storage time is called “ripening” by the tea drinkers in the culture of Yunnan Pu’er tea. The feature that Pu’er tea “tastes better with longer storage time “, has become an important consuming guidance in tea drinking and the tea price. Thus , using physical means to speed up the ripening of Pu’er tea is a hot spot in the field of tea study.
After treatment by High voltage pulsed electric field (HPEF),we found that tea polyphenols and theine significantly decreased with tea extract increasing. The ripening effect is the most significant In particular, under the treatment by HPEF-B(14KV/120Hz/60min) whether from the perspective of sensory evaluation or important tea physicochemical index. The research provides not only a new method for improving the quality of Pu’er tea, but also a theoretical basis for further industrialized treatment and acceleration of tea ripening process using high-voltage pulsed electric field to the Pu’er tea.


INTRODUCTION

Pu’er tea, a visiting card of Yunnan province is always popular in the market. It is made of Yunnan sun-fixed green rough tea of large-leaf variety produced in a certain range of Yunnan province, which can be produced by fermenting. It has a special quality. According to the processing techniques, it is categorized as raw and ripe tea(1), with characteristic fragrance, bright ,red liquor, and full taste(2). As is benifitial to human health in terms of special health care function and storage way featured”the longer storage,the better taste “, it is gradually known by the consumers all over the world.During the hundreds of years of production, people have found a set of procedures about the fermentation, storage and ripening of Pu’er tea leaves, of which the storage and ripening procedures ,as the crucial links, have attracted much attention particularly. The fresh Pu’er tea of current year tastes bitter, thus it needs to store for a long time to make it less bitter before mature ripening. With the improvement of people’s living standards and the recognization of Pu’er tea’s unique health functions, the demand for Pu’er tea ...