Inhibition of protein denaturation and oxidation of prepared shrimp paste by sturgeon skin collagen peptide

This study investigated the cryoprotective effect of different concentrations (0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) of sturgeon skin collagen peptides (CPs) on the changes in protein denaturation, oxidation, and overall quality of prepared shrimp paste during 180 d cryopreservation. Compared with phosphates and sorbitol, higher concentrations (>1.5%) of CPs minimized the denaturation and oxidation of protein with higher protein solubility, thermal transition enthalpy, and less carbonyl formation. Meanwhile, the decrease of hydrogen and ionic bonding was inhibited accompanied by less thawing loss and cooking loss. Compared with sorbitol, CPs at all concentrations contributed to less antioxidant effect in retarding the lipid oxidation after 180 d, however still exhibited lower thiobarbituric acid values than the control. The freshness of the 2.5% CPs group and sorbitol group was well maintained with the total volatile basic nitrogen value kept under 20 mg/100 g. Furthermore, a compact and less-aggregated gel matrix was observed during frozen storage. These findings indicate that CPs posed dose-dependent cryoprotective effects on shrimp paste, representing it as a comparable alternative to polyphosphates or sorbitol for seafood cryopreservation.