Functional and antioxidant properties of protein hydrolysates obtained from white shrimp (Litopenaeus vannamei)

Protein hydrolysates from white shrimp (Litopenaeus vannamei) with different degrees of hydrolysis (DH-10 and 20%) were prepared using the enzymes Alcalase 2.4 L and Protamex. The hydrolysates were evaluated for amino acid composition, solubility, foaming properties, emulsifying and antioxidant activity. All the hydrolysates showed high concentrations of Glutamic Acid, Aspartic acid, Arginine, Glycine, Lysine, Proline. It was found that the increase in the production of negatively charged amino acids was related to increase in DH. The hydrophobic amino acids were higher for hydrolysates obtained with Alcalase (10% DH) and Protamex (20% DH). The results indicated that higher degree of hydrolysis showed positive relation with the protein solubility of the hydrolysates, while negatively influenced foam and emulsification properties. The antioxidant properties presented by the white shrimp protein hydrolysates were influenced by the composition and peptides size. Hydrolysates with higher peptide chain showed the highest antioxidant power for the 2,2-Diphenyl-1-picrylhydrazyl radical scavenging and reducing power, while hydrolysates with lower peptide chain showed higher antioxidant power for 2,2'-azinobis (3-ethylbenzothiazoline sulfonic acid) radical scavenging. All hydrolysates showed dose-dependent antioxidant activities. Therefore, the results of the present study suggest that white shrimp is a potential source of protein hydrolysates as bioactive ingredients for the use in the formulation of functional foods as well as natural antioxidants in lipid food systems.