Rolling temperature affects green tea quality and non-volatile metabolites: Insights from integrated metabolomics and...

Rolling shapes green tea and affects its quality; however, the effect of rolling temperature on non-volatile metabolite (NVM) transformation remains unclear. In this study, we examined the effects of rolling temperature (15, 25, and 35 °C) on green tea quality using an integrated metabolomics and proteomics approach. In total, 168 NVMs and 11,111 proteins were identified. Multivariate statistical analysis revealed 22 key differential NVMs and 9 key differentially expressed proteins. Low-temperature rolling upregulated flavonoid 3-hydroxylase and dihydrolipoamide dehydrogenase expression while downregulating that of shikimate O-hydroxycinnamoyltransferase, Phosphofructokinase B domain-containing kinase, and β-glucosidase. These regulatory shifts promoted the accumulation of catechin and procyanidins B1/B4 (1.11-1.16-fold) while decreasing that of L-isoleucine (1.05-1.07-fold), hypoxanthine (approximately 0.74-fold), and xanthine (approximately 0.85-fold). Overall, low-temperature rolling effectively enhanced the refreshing and brisk taste of the tea liquor while reducing its bitterness. This study provides a theoretical foundation for the precision processing of high-quality green tea.