Production of Hydrolysate with Antioxidative Activity and Functional Properties by Enzymatic Hydrolysis of Defatted Sesame (Sesamum indicum L.)

Abstract

Sesame protein isolate is produced from dehulled, defatted sesame seed and used as a starting material to produce protein hydrolysate by trypsin and bromelain. The degree of hy- drolysis (DH), molecular weight distribution, DPPH radical-scavenging activity, and fibrinolytic activity of the hydrolysates were investigated. Within 120 and 240 min of hydrolysis, the maxi- mum cleavage of peptide bonds occurred was found for trypsin and bromelain, respectively, as observed from the DH (~ 20% DH). The antioxidant of enzymatically hydrolyzed sesame protein was also studied. For trypsin treatment, the hydroxyl radical-scavenging activity of hydrolysates appeared to reach a maximum level for 120 min of hydrolysis. The molecular weight of the hy- drolysates was also reduced significantly during hydrolysis. The hydrolysates treated by trypsin for 30 min (hydrolysis time) showed that more than 95% of < 50 kDa fraction was degraded. The molecular weight of the major band of the hydrolysates by trypsin was centred at 28 kDa. No significant changed were observed when treating with bromelain. The results suggested that the antioxidant activity of defatted sesame protein hydrolysates were related to its DH, hydrolysis time and molecular weight. Furthermore, fibrinolytic activity test demonstrated that the trypsin hydrolysate produced a lysed zone on the thrombin-clotted enzyme-induced fibrin plates. This indicates that trypsin hydrolysate function as a plasmin-like protease which can directly degrade the fibrin, thereby dissolving the thrombi rapidly and completely.