Antioxidant activity of protein hydrolysates derived from threadfin bream surimi byproducts

► Threadfin bream surimi byproducts are a potential source for production of protein hydrolysate. ► Pepsin-hydrolysed FBS showed the highest antioxidant activity based on free radical assays. ► FBS and RD hydrolysates protected HepG2 cells against oxidative damage. ► Virgibacillus sp. SK33 proteinase is a promising processing-aid for functional protein hydrolysate production.