PROTEIN PROFILES AND IN VITRO ANTIOXIDANT PROPERTIES OF MODIFIED SOY PROTEIN ISOLATES

Soy protein isolate was exposed to three different proteases, Alcalase, Papain and Flavourzyme for 30, 60 and 90 minutes. Hydrolysis was monitored by native and SDS-PAGE. The antioxidant properties of the hydrolisates were evaluated by free radical scavenging activity, reducing power and iron(II) chelating ability. The enzymes used affected the antioxidant properties of the soy protein isolate differently. Only Alcalase improved the free radical scavenging activity of the original isolate, while Alcalase and Papain improved the ability of the isolate to chelate ferrous ions. This suggests that the right choice of enzyme and conditions for modificationcan lead to isolates with improved functionality.