Changes of Metal Element Contents in Base Liquor for Maotai-Flavor Baijiu during Storage and Their Effects on Flavor Compounds

Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the contents of 25 metal elements in base liquor of different ages for Maotai-flavor Baijiu from three companies. A discriminant model was constructed using chemometrics to identify key differential metal elements. The results showed that the contents of metal elements in base liquor were positively correlated with age for each brand. Principal component analysis (PCA), hierarchical cluster analysis (HCA) and partial least squares discriminant analysis (PLS-DA) could effectively distinguish among six age groups; among them, PLS-DA had the best degree of discrimination, and the results of the PLS-DA model were consistent with those of the PCA model. Five key differential metal elements, namely Al, Ca, K, Na and Fe, were determined in the base liquor stored for 0–10 years by PLS-DA and one-way analysis of variance (ANOVA). The differential metal elements were found to play a positive role in the storage of base liquor through gas chromatography triple quadrupole mass spectrometry (GC-TQ-MS) detection. The discriminant model could discriminate base liquor of different ages from other companies. In summary, ICP-MS combined with chemometric analysis can effectively classify and identify base liquor of different ages for Maotai-flavor Baijiu, and determine the changes of metal element contents in base liquor for Maotai-flavor Baijiu during storage more accurately and efficiently