Abstract:

In this study, Aspergillus niger and Rhizopus isolated from Pu-erh tea and Eurotium cristatum isolated from
Fuzhuan tea were used for the fermentation of aqueous infusions of the sun-dried green tea as the raw material for Pu-erh
tea, respectively. Results showed that the content of tea polyphenols was significantly decreased with increasing
fermentation time. Aspergillus niger and Eurotium cristatum reduced the total flavonoid content by 72% and 31.76%,
respectively. On the contrary, Rhizopus increased the total flavonoid content by 94.92%. The contents of epiglloctechin
(EGC), epiglloctechingllte (EGCG), epicatechin (EC), epictechingllte (ECG) were significantly lowered, while catechin (C)
and gallic acid (GA) showed different variation patterns under the influence of different microbes. Theaflavins increased
firstly and then decreased by Aspergillus niger and Rhizopus, while Eurotium cristatum had the opposite effect. Thearubigins
content increased during the fermentation process. Theabrownins were increased significantly by Aspergillus niger and
Eurotium cristatum.

Key words: Aspergillus niger, Rhizopus, Eurotium cristatum, liquid-state fermentation, polyphenols