(1.北京工商大学 食品质量与安全北京实验室/中国轻工业酒类品质与安全重点实验室, 北京 100048;2. 中粮生化能源(肇东)有限公司, 黑龙江 绥化 152001;3. 吉林中粮生化有限公司 玉米深加工国家工程研究中心, 吉林 长春 130033)
(1. Beijing Laboratory of Food Quality and Safety / Key Laboratory of Alcoholic Quality and Safety of China Light Industry, Beijing Technology and Business University, Beijing 100048, China;2. COFCO Biochemical and Bioenergy (Zhaodong) Co Ltd, Suihua 152001, China;3. National Engineer Research Center of Corn Deep Processing, COFCO(Jilin)Bio-Chemical Technology Co Ltd, Changchun 130033, China)
The content of volatile components in edible alcohol is extremely low. However, these low volatile components directly affect the taste and grading of edible alcohol. Therefore, the superior and super grade edible alcohol were used as the research objects. The qualitative and quantitative analysis of the volatile components in the two grades of edible alcohol were performed by headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography/time of flight mass spectrometry (GC×GC/TOF MS). The volatile compounds identified in different grades of edible alcohol were used as variables, and multivariate statistical methods such as principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to establish a discriminant model for edible alcohol grading, and identified the main differential compounds between the two grades of edible alcohol. The results showed that a total of 60 volatile compounds were identified in edible alcohol of the superior and super grade. The discriminative model could effectively distinguish the edible alcohol of the super grade from superior grade. The contribution rate of the first two principal components of the PCA discrimination model was 51.3%, indicating that the model had good ability to differentiate edible alcohol grades. The fit index of the dependent variable of the PLS-DA discrimination model was 0.966, and the prediction accuracy of the model was 0.934, indicating that the model had good stability and prediction ability. Based on the analysis of the projection importance of the variables, 23 marker compounds were discriminated to distinguish between superior and super grade edible alcohol. Among them, the contents of ethyl decanoate, n-octane and cis-β-methylstyrene were significantly higher in super grade edible alcohol than those in superior grade edible alcohol. The contents of acetal, ethyl butyrate, 2,6-di-tert-butyl-p-methylphenol, ethyl valerate, styrene, ethyl heptanoate, ethyl acetate, ethyl hexanoate, acetic acid, ethyl benzoate, propanol, 1-methylnaphthalene, nonanal, n-hexane, benzaldehyde, 1,2,3,4-tetrahydronaphthalene, n-propylbenzene, (-)-limonene, γ-butyrolactone and hexanal were significantly higher in superior grade edible alcohol than those in super grade edible alcohol. The largest differences in the relative content of volatile components between the two grades of edible alcohol were acetal, ethyl butyrate, 2,6-di-tert-butyl-p-cresol and ethyl pentanoate. The results of the study were hoped to provide data reference and theoretical support for the objective discrimination of different grades of edible alcohol.