The effect of Eurotium cristatum (MF800948) fermentation on the quality of autumn green tea

•E. cristatum fermentation improved the aroma and taste quality of autumn green tea.•Increased terpene alcohols imparted fermented autumn green tea with flowery aroma.•Astringency of autumn tea was reduced by metabolizing catechins into theabrownins.•Theabrownins were observed to be umami but not astringent for the first time.•Results provided insights into utilizing autumn tea and reducing tea astringency. Autumn green tea (AT) has poor taste quality for its strong astringency. This study aims to improve the taste quality as well as the aroma of AT by Eurotium cristatum (MF800948) fermentation and to produce a fermented autumn green tea (FT). Results showed that the aroma quality of AT was improved, and the content of terpene alcohols that impart characteristic flowery aroma to FT significantly increased. The umami intensity of FT was comparable to that of AT while the astringency tasted much weaker mainly due to the oxidation of the catechins. The results also confirmed that theabrownins exhibited strong umami taste, not astringent taste. Finally, a metabolic map was analyzed to show the effect of E. cristatum (MF800948) on the quality of AT, and to visualize the changes of differential compounds in AT and FT. The work provides insights into the quality improvement of autumn green tea.