Differences in Aroma Components of Black Tea Processed from Different Tea Cultivars in Huangshan by Using Headspace-Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry and Odor Activity Value

In order to investigate the differences in the aroma composition of black tea samples made from different tea cultivars in the region of Huangshan, fresh leaves of nine tea cultivars widely planted in that region were selected to process black tea, including ‘Keemun Zhuyezhong’, the major cultivar for Keemun black tea processing, and eight clones, namely ‘Cuilv No.1’, ‘Fuzao No.2’, ‘Wancha No.4’, ‘Shuchazao’, ‘Wancha 91’, ‘Zhongcha 108’, ‘Zhenong 117’, and ‘Zhenong 139’. The sensory evaluation results showed that all nine black tea samples had a sweet aroma, and ‘Keemun Zhuyezhong’ black tea also possessed a strong floral scent. ‘Wancha No.4’ black tea also had a lightly floral aroma. The floral aroma of ‘Keemun Zhuyezhong’ and ‘Wancha No.4’ black tea was significantly stronger than that of the other cultivars. Forty-six major volatile compounds were identified by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and 21 volatile components with OAVs greater than one were found. Principal component analysis (PCA) showed that the aroma composition of ‘Zhuyezhong’ and ‘Wancha No.4’ black tea was clearly different from that of the others. Subsequently, seven differential components including (E)-β-ionone, linalool, β-myrcene, geraniol, hexanal, nonanal, and heptanal were identified by orthogonal partial least squares-discriminant analysis (OPLS-DA), with variable importance projection (VIP) values greater than one among all samples. These volatile components may be the dominant factors causing the aroma difference among the nine black tea samples. These results provide insights into the differential aroma compounds among black tea samples manufactured from different cultivars and the ‘Keemun aroma’.