Discrimination of different kinds of Luzhou-flavor raw liquors based on their volatile features

The volatile constitutions of 36 raw liquors from three distilling stages (head, heart and tail) of two typical Luzhou-flavor liquors (Fenggu-FG and Jiannanchun-JNC) were identified and semi quantified by gas chromatography-mass spectrometry (GC-MS). A total of 63 compounds were identified in all liquors. These two typical liquors had similar volatile constitutions, in which, 3-methylbutanol, hexanoic acid, ethyl hexanoate, ethyl butanoate, ethyl lactate, ethyl pentanoate, 1,1-dimethoxythane and 1,1-diethoxy-3-methylbutane were considered to be main compounds due to their high concentrations. Multivariate analyses including principal component analysis (PCA) and partial least square-discrimination analysis (PLS-DA) were conducted to reveal the detailed distinctions of liquors with different origins and reveal the volatile markers of several kinds of liquors. PCA explanation plane primary revealed the main differentiation between FG and JNC based on their loading plot values on axis PC1. Results of PLS-DA showed the detailed distinctions of liquors, suggesting that 2-methylpropanoic acid, butanoic acid, pentanoic acid, nonanoic acid, 2,3-butanediol, 1-hexanol, and ethyl nonanoate strongly correlated with FG liquors, while n-butylformate, isopentyl butanoate, isoamyl caproate, and p-cresol contributed to the specificity of JNC liquors. Furthermore, differences amongst the heart distilling stage liquors from different enterprises were also visualized in the two-dimensional PLS-DA discrimination plane. To our knowledge, this is the first article using the GC-MS paired with multivariate analysis to discriminate different kinds of Luzhou-flavor raw liquors.