Odorant capture-and-release in polymer cavities: Implications for red wine aroma from simulations on model wine solutions

The intricate interplay of volatile odour-active compounds with the complex matrix in red wine results in diverse aroma profiles. However, understanding how dynamic changes in odorant-polymer interactions influence odorant volatility and human sensory perception remains incomplete. This study combines classical all-atom molecular dynamics simulations with the all-electron perspective from electronic structure calculations to probe odorant binding dynamics to a high molecular weight polymer in model solutions. It delineates odorant migration mechanisms near polymers, unveiling a cooperative multi-segment aroma-binding effect with polymers exhibiting manifold binding sites and adaptable cavities for non-selective odorant attraction, capture, and release. The interplay of hydrogen bonding, polar, and non-covalent interactions governs aroma retention strength. In particular, this phenomenon explains long-term sensory perception, including the modulation of odour intensity changes in red wines' earthy notes, exemplified by 3-isobutyl-2-methoxypyrazine. These findings suggest the potential of customised polymers in fine-tuning red wine aroma perception. Abbreviations: 3-AFC: Three-alternative forced choice; Al: Aroma compound with index l; CHELPG: CHarges from ELectrostatic Potentials using a Grid-based method; COM: Centre of mass; DFT: Density functional theory; EtOH: Ethanol; ESP: Electrostatic potential; GAFF: General Amber Force Field; H ₂O: Water; HMW: High molecular weight; HPLC-MS/MS: High-Performance Liquid Chromatography-tandem Mass Spectrometry; HPLC-UV/Vis: High-Performance Liquid Chromatography with Ultraviolet/Visible Detection; HPPCs: High-molecular-mass polymeric polyphenols; MD: Molecular dynamics; NMR: Nuclear magnetic resonance spectroscopy; PBE0-D3BJ/6-31G(d): Density functional with dispersion correction / Gaussian basisset; PCM: Polarizable continuum model; PHPPCs: Purified high-molecular-mass polymeric polyphenols; PME: Particle-mesh Ewald method; PM3: Parametric method 3; PkRW: Polymer segment in red wine with index k; SI: Supporting Information; WH: Red wine polymer structure proposed by Wollmann and Hofmann.