Enhancing the Antioxidant Activity of Fish Scale Collagen Hydrolysates Through Plastein Reaction

An important area of focus for developing antioxidant collagen hydrolysates (peptides) involves enhancing the antioxidant properties of collagen hydrolysates. In this study, fish scale collagen hydrolysate (FH) was used as the raw material for plastein reaction. Various enzymes, including papain, alcalase, flavourzyme, and the combination of alcalase and flavourzyme, were employed for this purpose. The plastein reaction significantly improved the thermal stability, chemical antioxidant activity, and capacity to scavenge cellular reactive oxygen species of FH. Notably, the plastein reaction catalyzed by alcalase exhibited the most significant improvement, increasing the hydroxyl radical scavenging rate from 72.3 to 93.4% and restoring the viability of the oxidative stress-induced HepG2 cell model from 50.8 ± 1.7 to 74.9 ± 1.7%. During the plastein reaction, condensation and hydrolysis reactions occurred simultaneously, with condensation being the dominant process. These reactions, along with physical aggregation, facilitated the formation of larger yet more concentrated collagen peptide aggregates, leading to increased exposure of hydrophobic groups. This enhanced the uptake of collagen hydrolysates by the cells and contributed to the enhancement of their antioxidant properties. Thus, the plastein reaction is an effective method for enhancing the antioxidant properties of collagen hydrolysates, with its simplicity of operation and promising application potential.