Molecular insights into the antifreeze mechanism of collagen peptides based on their interaction with ice crystals.

This study explores the molecular-level cryoprotective effect of cod collagen peptide-1 (CCP-1) on surimi during freeze-thaw cycles, examining its interaction with ice crystals and its role in maintaining the structural integrity of surimi. Results indicated that CCP-1 exhibited the most effective cryoprotection on catalase, preserving 83.4 % of its residual enzyme activity, and prevented myofibrillar protein (MP) from freeze denaturation by sustaining the activity of Ca-ATPase and maintaining structural integrity. The antifreeze effect of CCP-1 (1.0 % and 3.0 %, /w) is comparable to that of commercial antifreeze containing 0.5 % compound phosphate (/w). Moreover, CCP-1's ability to interact with ice crystals is closely tied to its primary structure, where hydrophilic and hydrophobic amino acids work in tandem. Specifically, alkaline and acidic amino acids are capable of forming stronger hydrogen bonds, thereby enhancing their interaction with ice crystals. This work offers a theoretical basis for analyzing the binding behavior of antifreeze peptides with varying amino acid compositions.