Concentration-dependent modulation of the aroma profile of Jiang-flavor Baijiu by isoamyl alcohol through noncovalent interactions with key aroma compounds

Isoamyl alcohol (IAA), a key higher alcohol in Baijiu, is capable of both enhancing and disrupting aroma balance depending on its concentration. This study investigates its concentration-dependent role using recombination models with quantitative descriptive analysis, molecular dynamics simulations and 1 H NMR spectroscopy. At 200–400 mg/L, IAA enhanced floral and fruity aromas while suppressing acidic and roasted aroma, consistent with reduced compound volatility. Above 600 mg/L, the inhibitory effect on aroma release weakened. These concentration-dependent effects on aroma are driven by changes in compound volatility mediated by hydrogen bond, with van der Waals and Coulomb interactions contributing. 1 H NMR confirmed hydrogen bonding between IAA and aroma compounds via 0.05–0.09 ppm downfield shifts. Notably, the 400–650 mg/L range represents a pivotal transition window for sensory traits, compound volatility and hydrogen bond formation with IAA. However, a limitation remains in fully bridging the nonlinear gap between microscopic molecular interactions and human olfactory perception, as in vivo sensory integration involves complex perceptual mechanisms beyond physical volatility modulation. Download: Download high-res image (252KB) Download: Download full-size image