Stage-specific accumulation of characteristic aroma compounds in Lichuan black tea manufactured from 'Echa 10'

This study systematically investigated aroma dynamics across five consecutive processing stages (fresh leaves, withering, rolling, fermentation, drying) of Lichuan black tea (LCBT), a geographically indicated specialty tea from Enshi, China. Using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and multivariate statistical analysis, 81 volatile compounds were identified across all samples, with alcohols (25) and terpenoids (21) representing the two most abundant classes. Free volatiles peaked during rolling and fermentation, with stage-specific markers in fresh leaves and drying. Bound volatiles showed distinct accumulation patterns, with alcohols and aldehydes enriched at withering and rolling, ketones at rolling and drying, and acids declining continuously. Key aroma-active compounds followed stage-dependent patterns coupled with enzymatic and thermal reactions. Fermentation and drying selectively modulated volatile biosynthesis and release, ultimately shaping LCBT's signature floral and fruity aroma. The new fundamental insights into the process-aroma correlation mechanism were proposed during its manufacturing.