Molecular mechanism of aroma compounds affecting the flavor of Dixu green tea and their interaction with olfactory receptors

To investigate the dynamic changes in volatile organic compounds (VOCs) and their aroma contributions during the processing of Guangnan Dixu green tea, fresh leaves (XY), baked leaves (HQ), rolled leaves (RN), and dried tea (GC) were analyzed by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), combined with multivariate statistical analysis, odor activity value (OAV) evaluation, molecular docking, and molecular dynamics simulation. A total of 64 VOCs were identified across the processing stages, including alcohols, aldehydes, esters, ketones, alkanes, alkenes, and other compounds. Among them, 23 compounds showed OAV values > 1, indicating important contributions to the overall aroma profile. Multivariate analysis further identified four key differential aroma compounds in the dried tea, namely β-ionone, linalool, nonanal, and decanal. During processing, marked quantitative changes were observed in representative VOCs. For example, the relative content of Nonanal decreased from 210.69 µg/kg in XY to 53.61 µg/kg in RN, corresponding to a reduction of approximately 74.6%, while the proportion of aldehydes changed from 16.39% (XY) to 9.44% (HQ), then increased to 12.28% (RN) and 13.39% (GC). Molecular docking showed that the key VOCs exhibited favorable binding affinities toward olfactory receptors, with average binding energies ranging from − 4.95 to − 6.65 kcal/mol. Molecular dynamics simulations further demonstrated that the ligand–receptor complexes remained relatively stable over 100 ns, supporting the stability of these interactions. Overall, the results indicate that β-Ionone, linalool, nonanal, and decanal are key contributors to the characteristic aroma of Guangnan Dixu green tea, and that their dynamic changes during processing are closely associated with olfactory receptor interactions.