Volatile metabolomics highlights tea trichome's positive contribution to aroma and quality of white tea

Abstract

Tea trichomes, rich in secondary metabolites, are hypothesized to significantly influence white tea aroma, yet their biochemical contributions remain unclear. This study investigated the volatile profiles of tea trichome and tea body across six white tea samples using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and multivariate statistical analysis. Comparative analysis revealed significant differences in the volatile profile between tea trichome and tea body in all tested samples, with major differences lying in the content of volatile components. Sixteen potential key aroma components with relative odor activity value (ROAV) ≥ 1 and 39 aroma modifiers (0.1<ROAV<1) were identified in both tea trichome and tea body, predominantly associated with green, fruity, sweet, floral, woody and herbal aroma. In brief, trans-β-ionone, β-damascone, linalool, non-8-enal and (E,Z)-2,6-nonadienal were identified as key aroma components in both tea trichome and tea body, determining the basic aroma characteristic of white tea. Aroma modifiers were also affirmed, including β-myrcene, 2-ethyl-3,5-dimethyl-pyrazine, (E)-2-hexenal, dehydro-β-ionone, (Z)-6-nonenal, (E,E)-2,4-decadienal and benzeneacetaldehyde, which were shared by all samples in tea trichome and tea body. Notably, most of these key and modified aroma components showed higher relative contents and ROAVs in tea trichome than those in tea body. These data reveals that tea trichome positively enhance white tea's aroma quality, notably intensifying fruity, floral, sweet, green, and woody notes. This study systematically clarifies the biochemical specificity of tea trichome and their positive impact on white tea aroma, highlighting their critical role in aroma formation through differential accumulation of aroma contributors.