Abstract: The antioxidant effects of delipidized protein hydrolysate from  Martianus dermestoides Chevrolat beetles were studied. The delipidized proteins from the beetles were hydrolyzed by papain and then separated into three parts using two kinds of ultrafiltration membranes, which permit compounds with the molecular weights of 10 kDa and 6 kDa to pass through separately. The antioxidant effects of the three parts to free radicals O₂^-., DPPH·  and ·OH  were assayed by the methods of pyrogallol\|luminol, scavenging DPPH, Fenton and Oyaizu, respectively. The results showed that all the three parts of delipidized protein hydrolysates from the beetles had distinct scavenging effects, and the strongest effects were found in the hydrolysate with the molecular weight less than 6 kDa (P＜0.05). We so concluded that the delipidized protein hydrolysate from the beetle has good antioxidant effects.

Key words: Martianus dermestoides, delipidized protein hydrolysate, antioxidant effect, natural antioxidant, free radicals