Taste characteristics and symbolic metabolites of Rougui tea with different grades in China

The national tea standard sample is an important reference for the evaluation of tea grades. Clarifying the taste characteristics of different grades of Rougui tea (RGT) and its characteristic metabolites is of great significance for the standardization and scientificization of national standard samples. In this study, metabolites of different grades of RGT were analyzed by sensory evaluation and metabolomics, and symbolic metabolites were obtained and verified. The results showed that the higher the RGT grade, the stronger the mellowness and fresh and brisk taste, and the weaker the bitterness and astringency. Cyclo-glycyl-L-phenylalanine and calyxanthone can be used as the main symbolic metabolites to evaluate the quality of RGT, and their contents in 15 different grades of RGT verified the conclusion. This study lays an important foundation for the production of national tea standards and the measurement of commercial tea quality.