Molecular mechanisms of antifreeze natural deep eutectic solvents in frozen food systems: Hydrogen-bond network and ice regulation.

Controlling ice recrystallization and water dynamics is critical for frozen food quality, while conventional cryoprotectants primarily rely on colligative effects and provide limited molecular-level regulation of ice formation. Amino acid-based antifreeze natural deep eutectic solvents (AF-NADES) composed of glycerol, L-proline, and L-arginine were developed to modulate water and ice behavior through multivalent hydrogen-bond interactions. Among the formulations, the ternary glycerol-proline-arginine system (GPR) exhibited the strongest antifreeze performance, maintaining ice crystal areas below 1000 μm2 and effectively suppressing ice nucleation, recrystallization, and frost growth. GPR also showed the highest glass transition temperature (-59.3 °C) and flow activation energy (50.59 kJ·mol-1), indicating the formation of a highly interconnected and kinetically constrained network. Spectroscopic analyses and density functional theory suggested the presence of a heterogeneous hydrogen-bond network that may influence water organization and bulk water dynamics while preserving localized dynamic interactions. Application in surimi further confirmed its cryoprotective efficacy. Supplementation with 8% GPR reduced thawing loss to 1.02% and maintained water-holding capacity at 91.51% after 14 freeze-thaw cycles. AF-NADES may regulate ice formation through synergistic effects associated with vitrification-induced kinetic confinement and potential interfacial contributions to ice-growth inhibition. These findings highlight AF-NADES as a promising food-grade cryoprotectant for frozen food preservation.