Integrated metabolomics and electronic tongue analysis reveal dynamic changes in taste characteristics and non-volatile metabolites during Xinyang Maojian green tea processing.

As one of China's top ten famous teas, Xinyang Maojian (XYMJ) green tea lacks systematic research on dynamic variations of core taste metabolites throughout processing. This study combined metabolomics, multivariate statistics and electronic tongue evaluation to track its taste traits and metabolic fingerprints across sequential processing steps. 36 non-volatile metabolites were defined as pivotal differential metabolites. Fixation and initial drying were verified as decisive procedures shaping taste. Dynamic fluctuations of catechins, flavonoids, amino acids and carbohydrates jointly build sensory quality. Specifically, the improved in sweet taste attributed to the accumulation of soluble disaccharides (mainly sucrose), intensified umami was closely associated with the enrichment of glutamic acid, and the reduction in bitter and astringent aftertastes correlated with decreased levels of theobromine. Collectively, this study clarifies the key regulatory steps and target compounds during XYMJ green tea processing, providing theoretical basis for processing optimization and the directional improvement of its sensory quality.