GC-IMS and GC/Q-TOFMS analysis of Maotai-flavor baijiu at different aging times

There's a Chinese saying that the older the baijiu, the better it is. This study is an exploration of why baijiu are getting better during storaging. The aging mechanism of baijiu is still in the exploratory stage; therefore, this study used gas chromatography-ion mobility spectroscopy (GC-IMS) coupled with chemometrics and gas chromatography-quadrupole time-of-flight mass spectrometry (GC/Q-TOF MS) to analyze the volatile components of Maotai-flavor baijiu (MFB) at different aging times. Moreover, GC/Q-TOF MS was combined with a machine learning model to analyze the volatile components of MFB with different aging times to gain a deeper understanding of its aging mechanism. Nine major basal volatile organic compounds (VOCs) and 14 differential VOCs of MFB during the aging process were obtained using GC-IMS combined with visual mapping and differential analyses, and data refinement was performed using the GC/Q-TOF MS assay. With aging time, the total esters, except long-chain esters, decreased, and the total acid content increased. Based on these results, 21 characteristics were identified by combining random forest, support vector machine, and logistic regression models. These models were used to discriminate MFB with different aging times, which demonstrated the successful combination of multivariate analysis using multiple detection methods.