Effects of Protein Hydrolysate from Sheep Visceral on Oxidative Stability of Soybean Oil and Chicken Sausage

Sheep visceral protein hydrolysate (SVPH) was added to soybean oil (SBO) in a model system at 250, 400, 550 and 700 ppm and to chicken sausage as a food product at 700, 1,000 and 1,250 ppm. Thiobarbituric acid (TBA) and peroxide values were measured in all samples to evaluate antioxidant effects of the SVPH. SVPH (700 ppm) showed higher antioxidant effect (P < 0.05) in SBO as compared with Butylated hydroxytoluene BHT at concentrations lower than 550 ppm. Also, inclusion of SVPH in the chicken sausages resulted in a significant decrease (P < 0.05) in oxidation rate especially at 1,250 ppm, possibly due to free radical-scavenging ability of SVPH. Also the relatively low molecular weight peptides ranging from 316.80 to 12571.00 Da are mainly associated with their high antioxidant activity. Therefore, SVPH can be used in oils or lipid-containing products like sausage as an enriching additive and as a natural antioxidant. Practical Applications Nowadays, different protein sources have been used to produce protein hydrolysate containing bioactive peptides which are considered as inhibitor for oxidative progress in lipids and provide essential amino acids for human body. Therefore, slaughterhouse byproducts such as skin, blood and viscera are potential resources to produce these bioactive compounds throughout the world. It can be suitable to use these compounds in two systems including edible oil (model system) and food matrix for better evaluating their antioxidant effect.