A combined metabolomics and flavoromics approach reveals dynamic changes in non-volatile and volatile compounds of Tieguanyin tea during roasting process.

Roasting strongly influences the physicochemical properties, non-volatile and volatile compounds of tea, shaping the unique quality of the product. Therefore, this study used multi-omics to elaborate the dynamic changes in physicochemical properties, non-volatile and volatile compounds of Tieguanyin tea during the roasting processes. The results showed that the color of tea infusion gradually shifted with prolonged roasting time, the total sugar, caffeine, polyphenols, flavonoids levels significantly decreased, and the contents of free amino acids gradually decreased. Through the analysis of non-volatile compounds, a total of 1517 non-volatile compounds were identified, and different roasting stages showed unique non-volatile compounds. Moreover, volatile analysis revealed that a total of 77 volatile compounds were identified, among which acids accounted for the largest proportion. This study provides the first comprehensive insight into the dynamics of quality in Tieguanyin tea during roasting process, highlighted the importance of roasting time for the value-added utilization of Tieguanyin tea.