Investigation of the fruity and fermented off-flavors in peanut oil via molecular sensory science, S-curve method, and molecular docking

1) Freeze-thaw cycles induced potent fruity-fermented off-flavors in peanut oil 2) Ethyl 3-methylbutanoate and butanoic acid were identified as key drivers 3) A significant synergistic interaction between these fruity and fermented off-flavors 4) Hydrophobic interactions drive ethyl 3-methylbutanoate binding to olfactory receptor 5) A key hydrogen bond anchors butanoic acid binding within olfactory receptor The occurrence of fruity and fermented off-flavors significantly diminishes the quality and consumer acceptance of cold-pressed peanut oil (CPO). This study investigated the effects of freeze-thaw stress (0, 3, and 6 cycles) on the flavor of cold-pressed peanut oil and found that fruity and fermented off-flavors were significantly increased. Quantitative analysis and odor activity value (OAV) calculations confirmed ethyl 3-methylbutanoate (OAV=248) and ethyl 2-methylbutanoate (OAV=195) for fruity off-flavors, while butanoic acid (OAV=93) and 3-methylbutanoic acid (OAV=81) were key drivers of the fermented off-flavors. Crucially, the S-curve method revealed a synergistic interaction between ethyl 3-methylbutanoate and butanoic acid. Molecular docking revealed a preferential binding of ethyl 3-methylbutanoate to olfactory receptor OR11G2 (-7.2 kcal mol −1 ) driven by hydrophobic interactions. Butanoic acid was preferentially anchored in OR52E1 (-6.5 kcal mol −1 ), stabilized by a hydrogen bond to the receptor backbone and complementary hydrophobic interactions. These findings provide a scientific basis for improving the quality of cold-pressed peanut oil and preventing off-flavors.