Peptidomics & Molecular Simulation-Based Specific Screening of Antifreeze Peptides from Evynnis japonica Scale and the Action Mechanism

This study aims to explore the cryoprotective mechanisms of food-derived hydrolyzed peptides and develop novel cryoprotectants to enhance the quality of frozen foods. Evynnis japonica scale antifreeze peptides (Ej-AFP) were prepared using enzymatic hydrolysis, which had a 4-fold increase in protection efficiency for surimi compared to traditional cryoprotectants. Furthermore, Ej-AFP was able to control 63.60% of the ice crystals to sizes below 600 μm2. Three antifreeze peptide sequences were purified by using ice-affinity techniques and peptidomics. These sequences demonstrated a 21.75% enhancement in antifreeze activity and an increase of 1 °C in thermal hysteresis activity compared to Ej-AFP. Molecular simulation-elucidated ice-binding surface interacts with ice crystals through hydrogen bonds, while the nonice-binding surface disrupts the orderly arrangement of water molecules. This results in a tightly structured hydration layer around the peptide, increasing the curvature of the ice crystal surface and thereby demonstrating significant antifreeze activity in controlling ice crystal growth.