基于GC-QTOF MS结合化学计量学的三种香型白酒鉴别方法研究

Identification methods of three kinds of flavor-type Baijiu based on GC-QTOF MS and chemometrics

为快速鉴别不同香型的白酒,以3种香型(浓香、酱香、小曲清香)白酒的24个酒样为研究对象,采用气相色谱-四极杆飞行时间质谱(GC-QTOF MS)法检测其40种挥发性风味物质含量。对结果进行Z-score标准化后,结合层次聚类分析(HCA)、主成分分析(PCA)及偏最小二乘法-判别分析(PLS-DA)3种化学计量法,对酒样香型进行鉴别。结果表明,不同香型白酒间挥发性风味物质含量差异明显,且3种化学计量法能根据香型将3个香型的24个酒样进行有效区分,其中,PLS-DA的区分效果最好。利用PLS-DA结合变量重要性投影(VIP)值建立验证模型,确定己酸乙酯、乳酸乙酯等9种物质是导致不同香型白酒风味差异的主要物质(VIP≥1),建立的模型也能很好地将验证酒样按香型分类,可为白酒香型的快速鉴别分类提供科学有效的技术手段。

In order to quickly identify different flavor Baijiu,using 24 Baijiu samples with 3 flavor types(strong-flavor(Nongxiangxing),sauce-flavor(Jiangxiangxing)and Xiaoqu light-flavor)as the research objects,the contents of 40 volatile flavor compounds were detected by gas chromatography-quadrupole time of flight mass spectrometry(GC-QTOF MS).After the results were standardized by Z-score,the flavor types of Baijiu samples were identified by hierarchical cluster analysis(HCA),principal component analysis(PCA),and partial least squares-discriminant analysis(PLS-DA).The results showed that the contents of volatile flavor compounds in different flavor Baijiu were significantly different,and the 3 chemometric methods could effectively distinguish 24 Baijiu samples according to 3 flavor types,among them,PLS-DA had the optimal distinguishing effect.The validation model was established by PLS-DA combined with variable importance projection(VIP)value,9 substances such as ethyl caproate and ethyl lactate were identified as the main substances leading to the flavor differences of Baijiu with different flavor types(VIP≥1).The established model could also well classify the validated Baijiu samples according to flavor types,and provide a scientific and effective technical means for the rapid identification and classification of Baijiu flavor types.