Reveaing the dynamic changes of non-volatile metabolites and taste evolution of Duyun Maojian tea during the processing.

Duyun Maojian tea (DYMJ) is distinguished by its unique processing technique and "fresh, mellow, and sweet" flavor. However, its non-volatile metabolites (NVMs) and flavor profile formation remain unclear. Herein, 3024 NVMs were identified using widely targeted metabolomics during DYMJ processing, with fixation and distinctive drying steps (light-rubbing shaping and low-temperature roasting) emerging as the critical stages of metabolites transformation. Sensory evaluation and electronic tongue analysis indicated a reduction in bitterness and astringency, alongside enhanced umami and sweetness. Correlation analysis revealed 106 taste-related NVMs, including lipids (lysophosphatidylcholines), peptides (leucyl-valyl-alanine, L-phenylalanyl-l-glutamine), and flavonoid aglycones (quercetin) exhibited high correlation (|r| > 0.8, p < 0.01) with electronic tongue-measured umami, sweetness, and bitterness. Notably, fixation established the chemical foundation for DYMJ, whereas drying likely shape its flavor quality and taste profile, particularly fresh, mellow, and sweet character. These findings enhance our understanding of DYMJ flavor formation, and provide insights for optimizing green tea processing to improve flavor.