Dynamic changes in the major chemical and volatile components during the “Ziyan” tea wine processing

Among all types of tea beverage, tea wine uniquely combines the flavor of tea and wine, and its consumption is increasing in recent years. "Ziyan" tea wine is a new type of fermented tea wine rich in anthocyanins. The information about the dynamic changes of major chemical and volatile components in its processing is scarce. This study aimed to reveal the changes in sugar, total acids, catechins, anthocyanins and volatile components during "Ziyan" tea wine processing. Results showed that the total sugar, anthocyanin, and total catechins contents of the fermented tea wine were dramatically decreased, while epigallocatechin and epigallocatechin gallate retention remained high and the contents of caffeine and amino acids were not significantly impacted. 27 volatile fragrance compounds were generated during the fermentation process. Most of the volatile compounds in the tea leaves remain in the tea wine. The unique sweet and fruity aroma of "Ziyan" tea wine is mainly due to phenylethanol, octanoic acid, citric acid, and phenylacetaldehyde, which contain rosin, alcohol, etc. Overall, the findings provide systematic insights into the quality formation mechanism of "Ziyan" tea wine, especially in terms of aroma.