Pre-harvest cold treatment enhances the flavor quality of green tea: Insights from metabolomics, volatilomics, and sensory analysis during processing.

Pre-harvest cold treatment enhances tea flavor, yet the chemical mechanisms during processing remain elusive. This study investigated the impact of cold treatment on green tea quality using metabolomics, volatilomics, and sensory evaluation. Cold treatment significantly reduced astringency and enhanced umami, chemically attributed to a reprogrammed "high-amino acid, low-ester catechin" profile. Crucially, GC × GC-O-Q-TOF-MS revealed a dramatic enrichment of floral and fruity volatiles in the cold-treated group. Odor activity value (OAV) analysis identified trans-β-ionone as the critical impact odorant, exhibiting an over 1800-fold increase compared to the control. Integrated analysis suggested this aroma surge was closely associated with the priming of jasmonic acid (JA) and abscisic acid (ABA) signaling pathways, which upregulated key structural enzyme genes particularly during the spreading stage. These findings demonstrate that cold treatment effectively primes metabolic precursors for superior aroma formation, offering a novel strategy for high-quality green tea production.