Region-specific aroma profiles of dark tea: Differences in key odorants are driven by solid-state fermentation with three Aspergillus cristatus strains

To investigate the impact of geographically distinct strains of the same fungal species on the aroma of fermented tea, three Aspergillus cristatus strains were isolated from Fu brick teas produced in Shaanxi, Hunan, and Sichuan Provinces, China. These strains were subsequently used as inoculants to produce three distinct loose-leaf dark teas, designated SXFT, HNFT, and SCFT, respectively. Sensory analysis demonstrated that SXFT exhibited stronger flowery, sweet, woody, and minty aroma attributes than HNFT and SCFT. GC–MS analysis identified 89 volatile compounds and showed that total volatile levels increased significantly after fermentation, with SXFT showing the highest concentration (666.07 μg/L). Aroma recombination and omission assays revealed several distinct odorants: methyl salicylate, nonanal, linalool, and 6-methyl-5-hepten-2-one in the SXFT; linalool, β -ionone, and 6-methyl-5-hepten-2-one in the SCFT; and linalool, 6-methyl-5-hepten-2-one, and 1-octen-3-ol in the HNFT. These results provide a chemical basis for targeted starter selection in fermented tea production. • Three distinct LDTs were prepared using A. cristatum from different regions in China. • Sensory attributes and key odorants were differentiated significantly among the LDTs. • LDT sample named as SXFT showed both high aroma complexity and high volatile abundance.