A newly-discovered wild tea population: Elucidating the chemical basis of mellowness and richness during innovative black tea processing

Yongtai Wild tea (YT) shows distinct metabolic profiles from cultivar Funyun. • Flavone- C -glycosides, nucleosides & phenolic acids drive YT’s mellow and rich taste. • Upregulated CGTs and UGTs in YT may promote flavone- C -glycoside accumulation. • Docking of 12 metabolites to CaSR VFT domain reveals a kokumi-related mechanism. The innovative black tea processed from Yongtai wild tea (YT) population is characterized by mellowness and richness, yet its chemical basis remains unclear. In this study, Fuyun No. 6 (FY) cultivar was used as a control. Quantitative descriptive analysis (QDA) and metabolite profiling were performed on finished teas (YT-PT and FY-PT). Dynamic changes in moisture migration, enzyme activities, metabolomics, and transcriptomics were futher investigated to elucidatetaste formation mechanisms. Results showed that YT-PT exhibited significantly higher scores for mellowness and richness than FY-PT. Flavone- C -glycosides (e.g., apigenin-6,8-di- C -glucoside and luteolin-6- C -glucoside), nucleosides (adenosine and inosine) and phenolic acids (chlorogenic and cryptochlorogenic acids) were consistently more abundant in YT during processing, which may contribute to its characteristic taste. Transcriptomic analysis revealed that upregulated CGTs and UGTs in YT may redirect metabolic flux toward glycosylation, promoting metabolite accumulation. Molecular docking further revealed that these compounds bind with high affinity to the Venus Flytrap (VFT) domain of the calcium-sensing receptor (CaSR), potentially influencing kokumi perception and may contribute to the mellowness and richness of the tea. These multi-scale findings improve our understanding of wild tea and provide insights for its utilization in producing high-quality black tea. Download: Download high-res image (333KB) Download: Download full-size image