In vitro antioxidant properties of chicken skin enzymatic protein hydrolysates and membrane fractions

•Chicken skin protein hydrolysates scavenged various free radicals.•Antioxidant activity of the hydrolysates was dependent on enzyme type.•Membrane fractionation improved hydrolysate scavenging of superoxide radical.•Antioxidant activity was inversely related to peptide size. Chicken thigh and breast skin proteins were hydrolysed using alcalase or a combination of pepsin and pancreatin (PP), each at concentrations of 1–4%. The chicken skin protein hydrolysates (CSPHs) were then fractionated by membrane ultrafiltration into different molecular weight peptides (