Discrimination of Luzhou-flavoured fresh raw liquor distilled from Zaopei fermented in new, trend to-be aged and aged pit mud based on their aroma and flavour compounds

Abstract

Fresh raw liquors distilled from Zaopei fermented in new, trend to-be aged and aged pit mud, labelled as N1 and N2, T1 and T2, and A1 and A2, respectively, were analysed by sensory evaluation, two-dimensional gas chromatography/time-of-flight mass spectrometry with combined principal component analysis, gas chromatography–flame ionization detection, liquid chromatography–mass spectrometry with combined hierarchical cluster analysis, and partial least square–discrimination analysis. Results showed that samples had the same grouping situations by each method: the N-group containing N1 and N2; the T-group containing T1 and T2; and the A-group containing A1 and A2. The specific markers for the N-group liquors were 2-butanol and butanoic acid, and those for the A-group were 1-hexanol, ethyl pentanoate and 2-pentanone. The threshold contents of 1-hexanol, ethyl pentanoate, and 2-pentanone for the A-group liquors were 1207.95 ± 252.59, 469.89 ± 73.08 and 1105.12 ± 141.91 mg L−1, while those of 2-butanol and butanoic acid for the N-group liquors were 215.66 ± 179.50 and 430.65 ± 60.47 mg L−1, respectively. The results from modern chromatographic techniques and chemometric analyses verify the correctness of the traditional sensory evaluation used in controlling the quality of Chinese liquor, contribute to further studies related to the aroma and flavour of Chinese Luzhou-flavour of fresh raw liquors and may provide significantly helpful thresholds in distinguishing Chinese Luzhou-flavour fresh raw liquors distilled from Zaopei fermented in new, trend to-be aged and aged pit muds. Copyright © 2017 The Institute of Brewing & Distilling.