基于电子鼻与HS-SPME-GC-MS技术对不同产地黄观音乌龙茶香气差异分析

Differential Analysis of Aroma Components of Huangguanyin Oolong Tea from Different Geographical Origins Using Electronic Nose and Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry

为探究不同产地黄观音乌龙茶品质的差异,采用电子鼻结合顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)联用仪,对云霄和武夷山生产的黄观音乌龙茶香气成分进行分析。电子鼻实验结果表明,正交偏最小二乘判别分析能较好地区分两地黄观音乌龙茶。HS-SPME-GC-MS实验结果显示,两地黄观音乌龙茶共测出79个香气成分,其中17个差异香气物质可用于黄观音乌龙茶产地区分。香气活性值(odor activity value,OAV)分析结果表明,具有花香特征的茉莉酸甲酯、吲哚、茉莉酮、反式-橙花叔醇和茉莉内酯等香气成分在云霄黄观音中OAV较为突出,而具有花果香气特征的芳樟醇、癸醛、月桂烯、异戊醛和己醛等香气成分在武夷黄观音中OAV较为突出;产地判别结果表明,基于17个差异香气物质构建的支持向量机(support vector machine,SVM)模型判别率达到83.33%,其中5个重要香气成分(芳樟醇、反式-橙花叔醇、茉莉内酯、茉莉酸甲酯和吲哚)构建的SVM模型判别率为100%。本研究利用HS-SPMEGC-MS技术,筛选出与云霄黄观音和武夷黄观音乌龙茶品质相关的差异香气物质,并构建产地判别模型,为阐明两地黄观音乌龙茶的香气特征提供参考。

To investigate the differences in the quality of Huangguanyin oolong tea from different geographical origins, the aroma composition of Huangguanyin oolong tea produced in Yunxiao and Wuyishan was analyzed by using electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS). The electronic nose data showed that orthogonal partial least squares-discriminant analysis(OPLS-DA) could distinguish Huangguanyin oolong tea from different geographical origins. By HS-SPME-GC-MS, a total of 79 aroma components were identified,of which 17 aroma components were found to be significantly different between the two production regions and therefore could be used to distinguish the geographical origin of Huangguanyin oolong tea. According to odor activity values(OAV),methyl jasmonate, indole, jasmonone, E-nerolidol and jasmonolacton contributed greatly to the floral aroma of Yunxiao Huangguanyin tea, while linalool, decanal, laurelene, isovaleraldehyde and hexanal contributed greatly to the floral and fruit aroma of Wuyi Huangguanyin tea. The results of geographical origin authentication showed that the discrimination accuracy of the support vector machine(SVM) model based on the 17 differential aroma compounds was only 83.33%, compared to 100% based on five important aroma components(linalool, E-lactone, jasmonolactone, methyl jasmonate and indole). Our results will provide useful information for elucidating the quality characteristics of Huangguanyin oolong tea from Yunxiao and Wuyishan.