Antioxidant Activity of Faba Bean (Vicia Faba) Proteins Hydrolysates Produced by Alcalase and Trypsin

Enzymetic modification of proteins in order to break down specific peptide bonds and protein modification is widely used in the food industry. In this research, protein of faba bean seeds was hydrolyzed using alcalase and trypsin enzymes at three concentrations (1, 2 and 3%) and reaction times of 1-6 h at optimal temperature and pH of enzymes (50 and 37 °C, pH 8.5 and 7, respectively). Hydrolysis degree, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and iron chelating activity of hydrolyzed proteins were investigated. The results showed that the degree of hydrolysis increased with increasing reaction time and concentration of alcalase and trypsin enzymes. The time of hydrolysis and type of enzyme has a significant effect on the degree of hydrolysis, the antioxidant and chelating activity of the faba bean protein hydrolysates (P<0.05). The proteins hydrolyzed by alcalase at concentration of 3% and reaction time of 3 h had the highest antioxidant (75.41%) and metal chelating activity (55.95%). At the 1 and 2% concentration of trypsin, the highest DPPH radical scavenging activity was observed at 4 h which was 42.38 and 53.7 %, respectively. The most metal chelating activity in trypsin hydrolyzed treatments was observed in a reaction time of 2 h, after which the activity decreased. DPPH radical scavenging and metal chelating activity increased with increasing enzyme concentration. The results showed that alcalase have more efficiency in the production of anti-oxidant peptides compared to the trypsin.