Preparation And Antioxidative Stability Of The Potato Protease Inhibitors (Ppis) From Potato Starch Waste-Water

Potato protease inhibitors (PPIs) isolate, a major recovery protein from starch waste-water, possesses promising bio-activity and attracts growing attention. In this study, PPIs was extracted with a simple and cost-saving procedure, coupling salting out precipitation and isoelectric point precipitation. Antioxidant activity of PPIs isolate was evaluated by different methods. It displayed the good capacity for scavenging toward ARTS radicals (IC50 = 0.02 mg/mL) and inhibition of lipid pemxidation (IC50 = 0.30 mg/mL), especially, the IC50 was lower than that of ascorbic acid (V-E, IC50 = 0.44 mg/mL) and tocopherol (V-E, IC50 = 0.34 mg/mL). Moreover, the ARTS radicals scavenging ability remained high level at 50 degrees C and a pH range of 6-11; the inhibition of lipid peroxidation was stable at 25 degrees C and a pH range of 2-8. And all the antioxidant activities possessed satisfactory stability under ultrahigh-pressure condition. The results present great potential of PPIs as a high-quality protein with antioxidant function and to be used in functional foods.