Abstract:

Purpose: To optimize the fermentation process of green tea wine and investigate the changes in polyphenols,catechins and aroma components during fermentation. Methods: Orthogonal array experiments were used to optimizethe fermentation process. The changes in catechins and aroma components were determined by high performance liquidchromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Results: The optimal fermentationparameters were determined as follows: 4 g/L green tea infusion with 20% glucose and 50 g/L honey added, 5 g/L wine yeastinoculum size, and fermentation at 28 ℃ for 10 days. The contents of six catechins were increased during fermentation.Specifically, the contents of (－)-epigallocatechin (EGC), (－)-gallocatechin gallate (GCG), epicatechin gallate (ECG),and epicatechin (EC) were slightly increased; however, the contents of catechin (C) and epigallocatechin-3-gallate catechin(EGCGC) were increased by 10.88 and 17.33-folds, respectively. These results indicate that the increase of catechins playsan important role in the health-promoting function of green tea wine. There were 87, 88 and 94 aroma components in thewine at the initial and the last stages of fermentation and the aged wine, which accounted for 92.93%, 98.26% and 91.87%of the total volatile components, respectively. The significant differences in the types and amounts of aroma componentsindicate the transition from the tea flavor to the wine aroma components. Conclusions: Green tea can be fermented into wine;the health-promoting components (catechins) of green tea are increased to different extents and the green tea wine is mellow.

Key words: green tea wine, fermentation, catechin, flavoring compositions, variation