Differential analysis of stable isotopes and volatile flavor substances in jiangxiangxing baijiu from two different processes

Jiangxiangxing baijiu is one of the most popular baijiu in China because of its unique flavor characteristics. However, the differences in molecular and atomic levels between various processes of Jiangxiangxing baijiu remain unclear. The ethanol δ 13 C of 30 samples of daqu Jiangxiangxing baijiu (DQ-JX) and 25 samples of non-daqu Jiangxiangxing baijiu (NDQ-JX) were determined, and their distribution ranges were (−18.50 ± 0.68)‰ and (−15.64 ± 1.24)‰, respectively ( p  < 0.01) by Gas chromatography–isotope ratio mass spectrometry(GC–IRMS). The gas chromatography–mass spectrometry (GC–MS) analysis revealed that the contents of volatile compounds in DQ-JX were higher than those in NDQ-JX, but the proportions of ester and acid compounds of DQ-JX were lower. Orthogonal partial least squares discriminant analysis revealed that the two processes of Jiangxiangxing baijiu had significant classification effects, and 16 potential differential compounds were identified. The heat map analysis found that methanol, ethyl acetate, 1-propanol, and acetic acid were significantly higher in DQ-JX than in NDQ-JX. The accuracy of flavor compound identification model combined with stable carbon isotope analysis was 94.4%.