Characterization and Comparison of Aroma Profiles and Aroma-Active Compounds between Traditional and Modern Sichuan Vinegars by Molecular Sensory Science

Aroma profiles and aroma-active compounds of Sichuan vinegar, which is one of the four famous vinegars in China, were systemically analyzed by solvent-assisted flavor evaporation-gas chromatography-mass spectrometry (SAFE-GC-MS) and gas chromatography-olfactometry (GC-O). In addition, descriptive profile analysis, aroma reconstitution, and omission test were used to evaluate and compare the Sichuan modern vinegar (SMV) and Sichuan traditional vinegar (STV). A total of 99 volatile compounds were tentatively identified from the neutral and acidic fractions of both samples. Among them, 77 compounds were positively identified after comparison with their corresponding standards. Forty-two aroma-active compounds were characterized with flavor dilution (FD) factors from 1 to 6561 by aroma extract dilution assay (AEDA)-GC-O, with the highest for 2-hydroxy-3-butanone, butyrolactone, furan-2-carbaldehyde, acetic acid, and 3-oxobutan-2-yl acetate in both STV and SMV samples. Among them, 10 were identified for the first time in vinegar. Moreover, 40 aroma-active compounds were quantitatively determined, and 26 compounds exhibited their odor activity values (OAVs) larger than 1. The reconstituted solutions showed similar aroma profiles to the original samples in their characteristic aromas in terms of fruity, sweet, roasty, spicy, and woody notes but had slight differences in nutty and herbal notes.