Cryoprotective and antioxidative effects of gelatin hydrolysate from unicorn leatherjacket skin

• Hydrolysate from autolysed non-swollen skin showed high cryoprotective effect.
• Hydrolysate could protect protein denaturation of freeze-thawed washed mince.
• Hydrolysate was able to prevent lipid oxidation of freeze-thawed washed mince.

Cryoprotective properties of gelatin hydrolysates from autolysed non-swollen and swollen unicorn leatherjacket skin using partially purified glycyl endopeptidase (GE) from papaya latex were examined. Gelatin hydrolysates from autolysed non-swollen skin showed higher cryoprotective property in salt solution system than that from autolysed swollen skin as indicated by lower enthalpy for melting of eutectic and ice crystal. The cryoprotective effect of gelatin hydrolysate (0.5 and 1.0%) was in dose-dependent manner. Gelatin hydrolysate retarded physicochemical changes of natural actomyosin from washed mince system, as evidenced by lower changes in Ca2+-ATPase activity, surface hydrophobicity and disulfide bond formation, compared with the control. Based on DSC analysis, the enthalpy of myosin and actin was also higher in the presence of gelatin hydrolysate. Gelatin hydrolysate could prevent lipid oxidation in washed mince system as shown by lower TBARS value and less abundance of hexanal, heptanal and 1-pentene-3-ol.