Effects of different leaf colors on the quality of hawk black tea: sensory evaluation and metabolomics

Leaf color, a vital phenotypic trait, influences the flavor quality of tea. This study investigated the flavor and metabolite profiles of hawk black tea (HBT) processed from leaves of different colors. Sensory evaluation revealed that purple-leaf HBT (PHBT) exhibited prominent floral-fruity notes, green-leaf HBT (GHBT) showed fresh camphoraceous characteristics, while mixed-leaf HBT (MHBT) demonstrated optimal flavor with the highest overall acceptability. A total of 145 volatile compounds were identified, with 34 key odorants including linalool and trans- β -ocimene contributing to aroma perception. Notably, ten of these volatiles, including undecanal and hexanal, were identified as key differential aroma-active compounds. UHPLC-Q-Exactive/MS detected 258 identified differential metabolites, primarily flavonoids, terpenoids, amino acids, and organic acids. Flavonoid and phenylpropanoid biosynthesis metabolism, and amino acid pathways contributed to flavor differentiation. These findings elucidate the flavor and metabolic differences among HBT processed from different leaf colors, providing insights for targeted quality enhancement and optimization of processing suitability.