Insights into the Role of 2-Methyl-3-furanthiol and 2-Furfurylthiol as Markers for the Differentiation of Chinese Light, Strong, and Soy Sauce Aroma Types of Baijiu

The sensory impacts of two thiols, 2-methyl-3-furanthiol (MFT) and 2-furfurylthiol (FFT), in Chinese soy sauce aroma-type Baijiu (SSB), strong aroma-type Baijiu (STB), and light aroma-type Baijiu (LTB) (liquor) were evaluated and combined with partial least squares discriminant analysis (PLS-DA) to differentiate Chinese Baijiu. The flavor dilution factors of these two thiols ranged from 81 to 6561, and quantitative results showed that MFT and FFT were significantly more abundant (p < 0.001) in SSB than in STB and LTB. The determined odor activity values (OAVs) suggest that MFT (OAV: 34–121) and FFT (OAV: 11–103) contribute significantly to the overall aroma profiles of LTB and STB. Interestingly, the OAVs of these two thiols were high (256–263) and did not significantly differ (p > 0.05) in SSB. Notably, hierarchical cluster analysis and PLS-DA results revealed that these compounds can be used to differentiate Chinese LTB, STB, and SSB. According to their prominent organoleptic and distinguishing roles, these two thiols can be regarded as flavor markers for SSB.