Metabolomic analysis reveals the quality characteristics of Yi Gong tea leaves at different harvesting periods

To obtain a theoretical reference for understanding the changes in metabolites of Yigong tea leaves during different harvesting periods and to determine the optimal harvesting period, we performed a metabolome comparison using UPLC-Q-Exactive MS on Yigong tea leaves from different harvesting periods. The results indicated that a total of 41 metabolites were significantly altered during the growth of Yi Gong tea leaves. These involved 7 amino acids and their derivatives, 16 flavonols and flavonol glycosides, 4 organic acids, 3 catechins, 3 carbohydrates, 7 fatty acid esters, 1 terpene, and 3 substances from others. In particular, the levels of arginine and glutamine were higher in early-harvested tea leaves than in late-harvested tea leaves; the levels of flavonoids and flavonols were higher in late-harvested tea leaves. Metabolic pathway analysis revealed that the caffeine metabolism and the flavonoid biosynthesis perform key roles in Yigong tea leaves from different harvesting periods. PRACTICAL APPLICATIONS: At present, the application of metabolomics in tea research is focused on the study of pesticide residues, processing processes, environmental stresses, and regional differences. This study is to focus on the effect of the tea harvesting period on tea quality through metabolomics. Through metabolomics, we can better determine the optimal tea harvesting period, and this study can improve the quality of this tea product and may be able to bring some favourable favorable contributions contribution to the local tea marketing in the future.