Different distillation stages Baijiu classification by temperature-programmed headspace-gas chromatography-ion mobility spectrometry and gas chromatography-olfactometry-mass spectrometry combined with chemometric strategies

Liquid–liquid microextraction (LLME) combined with gas chromatography–olfactometry–mass spectrometry (GC–O–MS) was used to detect the variations in volatile compounds during the distillation process (head, heart, and tail) of raw Baijiu produced by different layers of fermented grains; 47 aroma compounds were sniffed and identified. Moreover, temperature-programmed headspace gas chromatography–ion mobility spectrometry (TP-HS–GC–IMS) was applied to characterize the Baijiu distillation process for the first time. The 3D fingerprint spectrum clearly showed a variation in volatile compounds from different distillation stages, and most compounds showed a downward trend. In addition, multivariate statistical analysis, including principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), etc., confirmed ten aroma active markers related to classification, indicating that these markers had a great influence on the flavor of raw Baijiu.