Molecular sensory basis of the smoky aroma in sesame oil elucidated by combining SAFE-GC-O-MS, σ-τ plot, and...

A moderate smoky aroma effectively balances the aroma of sesame oil; however, its specific molecular basis and the interaction mechanisms underlying its recognition by olfactory receptors (ORs) remain unclear. Herein, this study employed SAFE-GC-O-MS to identify key smoky aroma compounds in sesame oil produced from seeds roasted at 180 °C-260 °C. Based on the molecular basis of the smoky aroma of sesame oil produced from moderately roasted seeds (220 °C for 20 min; SO220), the σ-τ plot was used to evaluate the contribution of smoky aroma compounds, while computational simulations were applied to explore their interactions with human ORs. Guaiacol, 4-ethylguaiacol, 4-vinylguaiacol, and 4-methylphenol were identified as key smoky aroma compounds in SO220. Through reconstructive sensory experiments and a σ-τ plot, the first three compounds were found to significantly contribute to the smoky aroma of sesame oil. In particular, guaiacol and 4-ethylguaiacol were observed to have complete additive effects on the smoky aroma intensity, while 4-vinylguaiacol exhibited a partial additive effect. Molecular docking predicted favorable binding affinities between these three compounds and eight ORs through hydrogen bonding, hydrophobic, and π-π stacking interactions. Molecular dynamics (MD) simulations suggested a dynamic binding process, involving subtle protein structural adjustments and complex conformational changes that appeared to facilitate the formation of stable complexes. This study provides insights into the molecular basis of the smoky aroma in sesame oil and proposes a potential model for its interaction with ORs, thereby generating testable hypotheses for future biological validation.