Impact of spreading time on flavor quality in Duyun Maojian summer green tea

Duyun Maojian (DYMJ) is a prestigious green tea in China. The summer tea has higher tea polyphenols contents than spring tea, which reduces the green tea flavor quality and limits utilization of summer tea. Spreading is an important technology for optimizing tea quality, but its effect on DYMJ summer green tea is still unclear. In this study, we employed transcriptomics and volatile metabolomics to investigate the effect of spreading times (0, 1, 2, 3, 4, 5, 6, 7 h) on the flavor quality of DYMJ summer green tea. Sensory evaluation showed that the best taste was obtained at 4 h of spreading time. All indexes of main taste compounds reached peaking within 3–5 h (except for catechin). At 3–5 h of spreading time, important aromatic compounds with distinct floral and fruity flavors (such as phenylethanol, geraniol and cis -jasmone) were highest. Correlation analysis showed that there was a significant relationship between the main taste components and the tea aroma. In addition, transcriptomic analysis suggests that pathways related to hormone signaling and flavonoid biosynthesis in tea plants may play a key role in tea spreading. This study provides a theoretical framework for the processing of DYMJ summer green tea. • Explore the effects of spreading times on in DYMJ (Duyun Maojian) green tea made from summer tea. • DYMJ summer green tea has better taste quality and aroma when spread for 3–5 h. • Hormonal signal transduction may play a key role in the spreading time of DYMJ tea.