Urate oxidase treatment increases the quality of autumn Yellowish Yinghong 9 black tea.

Microbes can be used to improve the quality of fermented beverages and food. Colletotrichum camelliae is one of the most dominant fungi associated with tea leaves. In the present study, black tea produced from the autumn leaves of Yellowish Yinghong 9 was treated with C. camelliae urate oxidase (CcUOX) to determine whether this treatment could improve tea quality. The effects of recombinant CcUOX on several black tea quality parameters were assessed, such as liquor color, aroma, and levels of theabrownins, thearubigins, total polyphenols, catechins, caffeine, xanthine, and hypoxanthine. CcUOX treatment significantly affected the aroma composition and volatile compound profiles. Specifically, volatiles in the benzenoid/phenylpropanoid, fatty acid metabolism, and amino acid pathways were increased in CcUOX-treated black tea, whereas levels of volatiles in the terpineol and carotenoid pathways were reduced. This suggested that the balance of aroma constituents in Yellowish Yinghong 9 black tea was affected by treatment with CcUOX. The present study provides evidence that pre-treatment of black tea with a single enzyme from a common tea-associated microbe could significantly improve autumn tea quality, validating this method for use in further studies of tea improvement. • Treatment with a fungal-derived u rate oxidase (UOX) could improve black tea quality. • CcUOX treatment enhanced red brilliance, red evenness, sweet and mellow flavor, and high and sweet flavor of tea liquor. • CcUOX treatment significantly increased theabrownins, caffeine, xanthine, EGCG, and CG abundance. • CcUOX significantly increased concentrations of volatiles in the phenylpropanoid and amino acid pathways. [ABSTRACT FROM AUTHOR]