Determination of optimum conditions for production of antioxidant Peptides derived from hydrolysis of orange seed protein with alkalase enzyme

The use of enzymes for hydrolysis of protein sources is one of the common methods in the food processing. A hydrolysed protein is a complex mixture of peptides and amino acids that are obtained from hydrolysis by various enzymes, acids or alkali. These peptides play important biological role in the body. The orange seed is largely available from the orange juice industries wastes, and its defatted flour contains about 26% protein and can be used as a rich and cost-effective source for production of proteins and peptides of plant sources. In the present study, a protein isolate with high purity was extracted from defatted orange seed flour and then the protein was hydrolysed by using Alcalase enzyme in concentrations of 1, 1.5 and 3% and the hydrolysis time of 2-5 hours at temperature of 45-55 ° C at suitable pH for enzyme activity. Then the optimal conditions for the production of hydrolysed proteins with the highest antioxidant properties (DPPH radical scavenging activity, radical OH scavenging activity, ferric reducing activity and total antioxidant) were determined. Optimum treatment at determined conditions (temperature 54.8 °C, time 3.35 hr and ration of the enzyme to the substrate 1.7 % v/w) with antioxidant properties (DPPH radical scavenging activity (45.85%), radical OH scavenging activity (91.82%), ferric reducing activity (89.35%) and total antioxidant (39.68%) was obtained and antioxidant tests were performed on the optimal treatment for confirmation of the proposed values by software. The results showed that the hydrolysed protein derived from orange seed could be used in the foods formulation as a natural additive and also it can be used as a nutraceutical with high antioxidant ability.