Proteolysis coupled with membrane separation for the isolation of bioactive peptides from defatted smooth hound byproduct proteins

Abstract

Abstract The defatted viscera from smooth hound were the raw material used to produce four protein hydrolysates using three different microbial proteases (Neutrase, Esperase and Purafect) and the endogenous enzymes, named VPH-N, VPH-E, VPH-P and VPH-EE, respectively. Hydrolysates showed different degrees of hydrolysis (DH) depending on the enzyme used, where the VPH-P had the highest DH (30%). The amino acids (AA) characterization showed that Gly was the prominent AA (≥22%), followed by Ala, Glx, Lys, Asx, and Pro. In addition, the assessment of the antioxidant, ACE-inhibitory and antimicrobial activities revealed the high potentiality of the Purafect-hydrolysate. Therefore, it was selected to be fractionated by ultra-filtration according to their molecular weight (MW). Data showed that FIV (MW˂5 kDa) exhibited the best antioxidant activities. The differences detected in the bio-activities may be attributed, not only to the peptides size, but also to their sequences and hydrophobic AA contents. The antibacterial activity showed that the best inhibition values were recorded with FIV, particularly against S. typhi. Thus, the present results demonstrated the high potential of FIV from the VPH-P to be used a promising natural source of bioactive peptides in functional food formulations.