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

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.