How do green-leaf and yellow-leaf tea cultivars influence oolong tea flavor? Insights from metabolomic analysis with two Fujian traditional processing technologies

To elucidate the metabolic mechanisms underlying oolong tea flavor formation driven by cultivar genotype and processing technology, two cultivars, the green-leaf Mingke No. 1 and the yellow-leaf Jinguancha , were processed using traditional Fujian methods ( Minnan and Minbei ). Targeted GC–MS and untargeted LC–MS metabolomics, combined with sensory evaluation, identified 4578 metabolites, revealing distinct flavor profiles shaped by both cultivar and processing. Multivariate analysis (PCA and ASCA+) identified cultivar genotype and processing stage as the primary sources of metabolic variation. During withering and turning-over, enzymatic oxidation and degradation of lipids and amino acids generated aroma precursors, which were later transformed into complex aroma compounds through non-enzymatic thermal reactions. Mingke No. 1 excelled with the Minnan method, emphasizing clean floral notes and a brighter liquor, while Jinguancha thrived with the Minbei method, yielding a richer sweet–floral profile with nutty undertones and a reddish liquor. Cultivar primarily influenced bitterness, while processing method modulated floral, fruity, nutty, sweet, and off-flavors. Metabolic enrichment analysis revealed cultivar-specific differences in fatty acids, terpenoids, heterocycles, and flavonoids, aligning with sensory profiles. These findings provide a metabolic basis for optimizing oolong tea processing and quality control. • Oolong tea flavor is influenced by cultivar genotype and processing method. • Minnan processing preserves floral-fresh notes; Minbei enhances sweet-floral complexity. • ASCA + analysis identifies cultivar and processing stage as key metabolic drivers. • Metabolomics links cultivar traits with processing strategies for flavor optimization.