Integrated multi-omics analysis reveals flavor characteristics and underlying formation mechanisms during withering of Huangjincha black tea

Huangjincha black tea, a high-amino-acid specialty cultivar, is prized for its refreshing taste and distinctive floral aroma; yet, molecular mechanisms governing flavor formation during withering remain unclear. This study integrated sensory evaluation, metabolomics, transcriptomics, proteomics, and quality-related chemical analyses to systematically elucidate the dynamic shifts and biosynthetic mechanisms underlying flavor formation during withering. Sensory evaluation and quality-related chemical measurements showed that moderate withering reduced bitterness and astringency while enhancing sweetness, umami, and mellowness in the tea infusion. Metabolomic analysis revealed significant accumulation of free amino acids, amino acid derivatives, and phenolic acids, accompanied by decreases in catechins and flavonoids during withering. Integrated transcriptomic and proteomic analyses identify amino acid and secondary metabolism as dominant processes during withering. CsSHMT1 , CsCAT1 , and CsGABA-T3 were identified as hub genes regulating amino acid metabolism. Notably, the phenylpropanoid pathway was identified as a pivotal metabolic hub that mechanistically links amino acid metabolism with aroma formation, thereby promoting the biosynthesis of key aroma-related compounds, including ferulic acid, coniferyl-aldehyde, and methyleugenol. These findings elucidate the coordinated metabolic and regulatory networks shaping flavor formation during withering, thereby providing a mechanistic basis for the targeted regulation of flavor in high-amino-acid black tea processing. • Multi-omics analysis revealed flavor formation mechanisms in Huangjincha black tea. • Amino acids, phenolic acids and terpenoids accumulate during withering. • Amino acid and phenylpropanoid pathways were key to flavor development. • Ferulic acid, coniferyl-aldehyde, methyleugenol, and phenylalanine increased significantly. • Co-regulation of genes and metabolites shapes umami-sweet and floral flavor formation.