Characterization of odor-active compounds in Dahongpao Wuyi Rock Tea (Camellia sinensis) by sensory-directed flavor analysis

Different methods for extraction and analysis of odor-active compounds in Dahongpao (DHP) Wuyi Rock Tea (WRT) were compared. The results showed that two-dimensional gas chromatography–olfactometry–mass spectrometry (GC×GC–O–MS) is a better method than GC–O–MS, stir bar sorptive extraction (SBSE) can extract more odor-active compounds. Aroma extraction dilution analysis (AEDA) and odor activity value (OAV) further indicated that 15 compounds were the most important odor-active compounds in DHP: phenethyl alcohol, (E)-β-ionone, nonanal, linalool, hexanal, geraniol, benzaldehyde, α-ionone, methyl salicylate, 6-methyl-5-hepten-2-one, geranylacetone, benzyl alcohol, tea pyrrole and hexyl hexanoate. The roasting process affected the overall odor characteristics of DHP, and appropriate roasting would enhance the sensory quality of DHP. As the roasting temperature increases, the contribution of compounds such as tea pyrrole, 2-ethyl-6-methylpyrazine, and 2,6-dimethylpyrazine to the roasted and burnt odor of the samples gradually increase, and the concentration of typical floral compounds such as phenethyl alcohol, (E)-β-ionone, α-ionone and linalool increase decidedly under light fire roasting, which was consistent with the sensory evaluation results. This study is helpful to further guide the production process of DHP.