Characterization of key aroma-active sulfur-containing compounds in Chinese Laobaigan Baijiu by gas chromatography-olfactometry and comprehensive two-dimensional gas chromatography coupled with sulfur chemiluminescence detection

Volatile sulfur-containing compounds (VSCs) often exist at extremely low concentrations, making them difficult to be determined. The VSCs in Laobaigan (LBG) Baijiu were analyzed by headspace solid-phase microextraction (HS–SPME) coupled with GC × GC–SCD, by which 12 VSCs were identified. Among the 65 odor-active compounds that were determined by GC–O with the aid of aroma extract dilution analysis (AEDA), benzenemethanethiol and 2-methyl-3-furanthiol were found to possess the highest FD values of 6561. The limits of detection (LODs) of the identified VSCs determined by GC × GC–SCD were found to be extremely low at 0.05–1.53 ng/L, with their analytical recoveries from 85% to 116%. The VSCs in the LBG samples were determined in a range of concentrations from 0.77 ± 0.02 µg/L to 60.04 ± 2.32 µg/L. Benzenemethanethiol, dimethyl trisulfide, 2-methyl-3-furanthiol and 2-furfurylthiol exhibited odor activity values (OAVs) > 100 and significantly contributed to the overall aroma of LBG Baijiu.