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 cat...