基于香气指纹图谱和多元化学计量法对黄金茶2号等级的判别分析

Grade Identification of Huangjincha Tea 2 by Aroma Fingerprinting Combined with Multivariate Chemometric Analysis

以黄金茶2号为研究对象,采用顶空固相微萃取-气相色谱-质谱联用技术建立不同等级黄金茶香气成分气相色谱-质谱指纹图谱,并通过化学计量法对两个等级的黄金茶进行判别分析。研究表明,2个等级的黄金茶中鉴定出81种香气组分,其中41种为共有香气组分。基于共有香气组分的正交偏最小二乘判别分析可以区分2个等级黄金茶,并筛选出9种差异香气组分,分别是庚醛、柠檬烯、反式-β-罗勒烯、1-辛醇、反式-4,8-二甲基-1,3,7-壬三烯、反-橙花叔醇、1,10-diepicubenol、epicubenol、十六酸甲酯。以9种差异香气组分为变量建立的线性判别方程对2个等级的黄金茶进行等级判别,自身验证和交叉验证正确率为100%。本实验结果可为黄金茶的分级提供客观量化的参考依据。

The aroma components of two grades of Huangjincha tea 2 were investigated by using headspace solid-phase microextraction(HS-SPME) coupled with gas chromatography-mass spectrometry(GC-MS) to establish their aroma fingerprints. The results were analyzed using chemometrics. Totally 81 aroma components were identified, 41 of which were common to both. Based on these common aroma components, the two grades could be discriminated by orthogonal partial least squares-discrimination analysis(OPLS-DA), and nine differential aroma components between them were identified including heptanal, limonene, trans-β-ocimene, 1-octanol,(E)-4,8-dimethylnona-1,3,7-triene, trans-nerolidol,1,10-diepicubenol, epicubenol, and methyl hexadecanoate. A linear discriminant model to distinguish the two grades was established using the differential aroma components as independent variables. The self-validation and cross-validation accuracy of this model were 100%. These results may provide an objective and quantitative reference for the classification of Huangjincha 2.