Application of metabolic fingerprinting in tea quality evaluation

Traditional tea grading depends on subjective sensory assessment, lacking objectivity. This study employed comprehensive metabolomic analysis and sensory evaluation on 161 tea samples to identify potential gradingrelated metabolites. Amino acids, lipids and organic acids predominantly determined the superior quality of green, yellow, and white teas, respectively, while flavonoids adversely affected their quality. The identified metabolic markers were effectively utilized for predicting tea sensory scores. Specifically, methionine derivatives and glutamate dictated green tea's sweet and umami taste. Glycerophospholipids (PCs and PEs) were positively correlated with appearance, aroma, and taste in yellow tea, while glycerolipids (MGDGs, SQDGs, and DGDGs) had negative visual associations. Fumaric acid and succinic acid bolstered fresh and umami flavor white tea. These findings suggest metabolomics holds promise for precise tea grading, using identified compounds as potential quality markers. Moreover, the health benefits of premium teas were emphasized by key metabolites like NAD, pantothenic acid, and fumaric acid.