Differences in Volatile Compounds in Maotai-Flavored Baijiu Produced by Different Processes

Gas chromatography (GC) and gas chromatography-mass spectrography (GC-MS) were used to identify and quantitate the volatile substances in Maotai-flavoured baijiu produced by two different processes. A discriminant model was established based on odor activity value (OAV) by chemometrics and the key differential substances were identified. The results showed that the contents of volatile compounds in baijiu made from ground sorghum were lower than those in baijiu made from whole sorghum, but the proportions of esters, acids and aromatic compounds were higher, indicating that baijiu quality may be related to the proportion of each compound. Baijiu blends at different ratios were prepared to validate the applicability of the proposed model, four-fifths of which were used as training set, and the remaining one-fifth were used as testing set. The overall accuracy rate was 93.33%, indicating that the model could discriminate the two baijiu samples. The distribution of 9 different proportions of mixed samples in the model showed that it could also be used for preliminary identification of mixed samples, which verified the applicability of the model. In addition, 14 potential differential compounds were identified, and their effectiveness in discriminating the two processes was confirmed by the clustering heatmap. Among these compounds, the variable importance in the projection (VIP) value of furfural was the highest, and the OAV of furfural differed greatly between the two baijiu samples, indicating that furfural may be an important substance causing the difference between the baijiu samples.