Antioxidative activity of protein hydrolysate produced by alcalase hydrolysis from shrimp waste (Penaeus monodon and Penaeus indicus)

Protein hydrolysates prepared by hydrolysis of shrimp waste (Penaeus monodon and Penaeus indicus) for 90 min. using Alcalase enzyme following pH-stat method. Antioxidative activities of SWPH were assessed determining FRAP, ABTS and DPPH radical scavenging activities, which increased linearly with increasing concentration of protein hydrolysate upto 5 mg/ml maintaining good correlation. SWPH showed high stability over wide ranges of pH (2-11) and temperature (up to 100 °C for 150 min), in which the activity of more than 80% was retained. Protein hydrolysate solution with a concentration of 5 mg/ml significantly lowered TBA values of Croaker fish fillet and maintained yellowishness of skin colour compared to untreated control sample during 10 days of refrigerated storage at 4 °C. SWPH also restricted the increase of PV and FFA values in Croaker fish fillet within acceptable limit.