Headspace solid-phase microextraction (HS-SPME) coupled with comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry (GC × GC-Q-TOF-MS), sensory evaluation, and odor activity value (OAV) analysis were employed to systematically identify and trace the key aroma compounds of jasmine yellow tea. The findings indicated that the scenting process significantly enhanced the aroma quality of yellow tea, with tea scented with 90%–120% jasmine flowers showing the best overall aroma profile. Thirteen key aroma compounds were identified in jasmine yellow tea, including linalool, benzyl acetate, α-farnesene, methyl benzoate, cis-3-hexenol benzoate, indole, and methyl salicylate. Among these, eight compounds were found to be more abundant in jasmine flowers, suggesting that the release of major aroma constituents from jasmine flowers during scenting is closely associated with the aroma characteristics of jasmine yellow tea. Correlation analysis revealed that these eight compounds were significantly positively correlated with both the aroma intensity and overall sensory score of jasmine yellow tea (P < 0.05). Notably, cubaene (woody and resinous notes) and cis-3-hexen-1-ol (grassy aroma) may contribute synergistically to the layered aroma of jasmine yellow tea. This research provides a theoretical foundation for the quality control and processing optimization of jasmine yellow tea. However, further studies are warranted to determine the optimal processing parameters.

To explore the differences in aroma between compressed dark tea and raw dark tea, headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and sensory evaluation were used to analyze and compare the flavor quality and aroma composition of four kinds of Hunan compressed dark tea and raw dark tea stored under the same condition. The results showed that compared with the raw tea, the pine smoke-like aroma and the crude, green, sour and other miscellaneous off-odors of the compressed tea were weaker, the concentration of aroma was higher and more long-lasting, and the stable flavor was more prominent. Furthermore, the contents of 15 unpleasant aroma components such as (E,Z)-2,4-heptadienal, 2,3,5,6-tetramethylpyrazine, and acetic acid in the compressed tea decreased, while the contents of 11 pleasant aroma components such as (E,E)-2,4-heptadienal, saffron aldehyde and butylated hydroxytoluene increased. Through principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), 10 characteristic aroma components which could potentially be used to discriminate between compressed dark tea and raw dark tea were identified including acetic acid, 2-butyl-1-octanol, 1,2,3-trimethylbenzene, (Z)-2-decylenaldehyde, linalool, octanol, α-terpineol, 3-tridecanone, (E,Z)-2,6-nonadienol and phenylethanol. These results can provide a reference for further research on the quality formation mechanism of Hunan dark tea and the development of dark tea products.