Evaluation of marine peptides antioxidant activity by DPPH assay

Oxidation is the loss of electrons or an increase in the oxidation state. Antioxidants are compounds that caninhibit oxidation, a chemical reaction that can produce free radical, a hazardous substance which increasingly causesDNA mutation, carcinogenesis, atherosclerosis and aging. Natural extracts such as vitamin E, C , and A are thesources of many antioxidant substances. They have proven to be useful as supplements preventing diseases causedby oxidative stress. Peptides can exert antioxidant activity by the same mechanisms as those observed for otherantioxidants. In all reviews, meat, fish, and milk proteins were shown as important sources of bioactive peptides.Marine by-products, as potential bioactive sources of antioxidant peptides have shown to have significant biologicalactivities such as, anti-hypertensive, anti-proliferative, anti-obesity and anti-diabetic. Marine bioactive peptidesbased on their structural properties, amino acid composition and sequences have been shown to display a wide rangeof biological functions. To find a new antioxidant source, protein extracts from a fresh Persian Gulf shrimp weresubjected to enzymatic hydrolysis using alkaline proteases. Molecular weight separation was done by ultrafiltrationmethod. The various separated hydrolysates were then tested for antioxidant properties. Antioxidant capacity wasdetected by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Results showed that proteinhydrolysates of all molecular weights exhibited strong antioxidant properties. In particular, protein hydrolysates withhigher than 30 kilo Dalton were found as a strongest hydrolysate with the highest free radical inhibition in DPPHassay. These results revealed the potential of bioactive peptides from Persian Gulf shrimp for use as food additivesor supplements.

Evaluation of marine peptides antioxidant activity by DPPH assay Keywords:

Antioxidant , Marine peptides , DPPH