Dynamic Changes in Flavor Quality of Wuyi Rock Tea at Different Storage Times

Seven samples of Wuyi rock tea (cv. Shuixian) stored for different times (0, 5, 10, 15, 20, 25, and 30 years) were collected to investigate the effect of storage time on the flavor quality of Wuyi rock tea by the combined use of sensory evaluation, non-volatile and volatile composition analysis and chemometrics methods. The results showed that the transformation of the flavor quality of Wuyi rock tea during storage was divided into three stages: 0-5, 10-15, and 20-30 years. As the storage time increased, the taste gradually transformed from mellow to stale, and a sour taste appeared at the middle stage of storage and then faded away at the late stage. The aroma gradually changed from flowery and fruity to aged, woody and herbal. A significant decrease in the content of tea polyphenols, catechins-like and theaflavins and an increase in the content of soluble sugars were the major reasons for the taste changes. Changes in the contents of 15 characteristic volatiles, including indole, trans-nerolidol, dihydroactinidiolide, hotrienol, α-terpineol, methyl salicylate, β-ionone, and (Z)-hexanoic acid-3-hexenyl ester, were the key factors affecting the aroma changes. This study provides a scientific reference for the storage and consumption of Wuyi rock tea.