Comparative Metabolomic Analysis Reveals the Differences in Nonvolatile and Volatile Metabolites and Their Quality Characteristics in Beauty Tea with Different Extents of Punctured Leaves by Tea Green Leafhopper

The fresh leaves were processed into beauty tea from the Camellia sinensis "Jinxuan" cultivar, which were punctured by tea green leafhoppers to different extents. Low-puncturing dry tea (LPDT) exhibited a superior quality. Altogether, 101 and 129 differential metabolites, including tea polyphenols, lipids, and saccharides, were identified from the fresh leaves and dry beauty tea, respectively. Most metabolite levels increased in the fresh leaves punctured by leafhoppers, but the opposite was observed for the dry beauty tea. According to relative odor activity values (rOAVs) and partial least-squares discriminant analysis (PLS-DA), four characteristic volatiles, including linalool, geraniol, benzeneacetaldehyde, and dihydrolinalool, were selected. Mechanical injury to leaves caused by leafhoppers, watery saliva secreted by the leafhopper, and different water contents of the fresh leaves in different puncturing degrees are the possible reasons for the difference in the quality of the beauty tea with different levels of puncturing. Overall, this study identified a wide range of chemicals that are affected by the degrees of leafhopper puncturing.