Congou black tea has garnered significant interest among customers because of its distinctive floral-fruity aroma. To determine the differences in characteristic volatile compounds among various varieties, a total of 147 volatile compounds were identified across 25 samples via gas chromatography–mass spectrometry (GC-MS). Through hierarchical clustering analysis (HCA), 25 samples were classified into two clusters, in which the Fuding variety, Jinguanyin variety, Huangguanyin variety, and Meizhan variety were clustered into one category, whereas the Sichuan population variety was clustered into the other. These two categories were further analyzed via orthogonal partial least squares discriminant analysis (OPLS-DA), and 48 differential compounds were identified. The Sichuan population variety was found to contain a higher concentration of floral and fruity aroma compounds while exhibiting fewer green or grassy odor compounds. To explore the floral-fruity aroma components of Sichuan Congou black tea (SCBT), forty-nine aroma-active compounds were identified through multidimensional GC–MS/olfactometry (MDGC-MS/O). Among them, six components with odor activity values (OAVs) ≥1 were regarded as key floral-fruity aroma components. Recombination and omission tests ranked the contributions of these compounds as follows: geraniol, linalool, methyl salicylate, benzeneacetaldehyde, beta-myrcene and benzaldehyde. Addition experiments confirmed for the first time that linalool, beta-myrcene and methyl salicylate are the key citrus-like compounds, offering valuable insights for the exploration of germplasm resources and quality control of black tea with special aromas.
Xianxiu Zhou,Jiajing Hu,Hongchun Cui,Jiahao Tang,Yongwen Jiang,Haibo Yuan,Jiahua Li,Yanqin Yang
Floral–fruity aroma Pu-erh tea (FFAPET) is highly valued by consumers for its distinctive and appealing fragrance. This study conducted a comprehensive investigation into the volatile components of FFAPET using advanced analytical techniques, including GC-O-MS, GC-MS/MS, aroma recombination, and omission tests. Compared with traditional stale aroma Pu-erh tea, FFAPET exhibited higher levels of alcohols and alkenes. Through GC-O-MS combined with OAV analysis, 10 key active-aroma compounds were identified in representative FFAPET samples. These compounds included (E, E)-2,4-heptadienal, phenylethyl alcohol, geraniol, (E,Z)-2,6-nonadienal, (Z)-4-heptenal, 2-phenethyl acetate, 2,2,6-trimethylcyclohexanone,D-limonene,β-ionone, and linalool, all of which made significant contributions to the development of the characteristic floral–fruity aroma profile. Tests involving aroma recombination and omission further confirmed that seven of these odorants played essential roles in defining the overall aroma of FFAPET. These findings offer valuable theoretical insights for the enhancement and regulation of Pu-erh tea flavor, particularly for the optimization of the floral–fruity aroma characteristics.