Identification of novel antifreeze peptides from yak skin gelatin ultrasound-assisted enzymatic hydrolysate.

In this paper, a new type of antifreeze peptide was identified from the ultrasonic-assisted enzymolysis product of yak skin. First, the antifreeze peptides were obtained by ultrasonic-assisted enzymolysis of yak skin gelatin. The obtained peptides with 150 W ultrasound treatment could increase the survival rate of Lactobacillus plantarum from 16 % to 60 % after four freeze-thaw cycles. Then, the component with the highest antifreeze activity in the peptides' ultrafiltration product was analyzed by LC-MS/MS to obtain 961 peptides. After screening of antifreeze activity and physical properties, three antifreeze peptide sequences were obtained (S1: GERGGPGGPGPQ, S2: PGGAEGPGRDAQQP, S3: VAPPGAPKKEH). DSC analysis, Lactobacillus plantarum cryoprotection experiments and molecular docking showed that the S1 sequence had the best antifreeze activity. This study provides a new idea for the high-value utilization of yak by-products and a potential candidate for food antifreeze agents.