Abstract:This study investigated the effect of enzymatic hydrolysis on antioxidative activity of freshwater clam, followed by comparing the differences in activity and chemical nature between the extracts prepared by different extraction conditions and fractionated by ion-exchange columns. Three commercial enzymes, flavourzyme, alcalase and protamex, were used respectively to hydrolyze the dry meat at 50℃ for up to 12 hours. With the exception of an increase in reducing power, the inhibition of linoleic acid peroxidation and scavenging α, α-diphenyl-β-picrylhydrazyl (DPPH) radical effect did not increase or even decreased in all hydrolysates. Hot water (HW), HW-80% ethanol (HW-EtOH), and EtOH extracts were then prepared from dry meat and determined at various concentrations. Results revealed that the antioxidative capacity of freshwater clam was contributed by low-molecule-weight components. The IC50 values measured for EtOH extract decreased to 5-8% of that for HW extract. Somewhat differences in the kinds of constituents and chemical natures between HW-EtOH and EtOH extracts were also obser.