Five commercially available food-grade microbial protease preparations were evaluated for their ability to hydrolyse meat myofibrillar and connective tissue protein extracts to produce bioactive peptides. A bacterial-derived protease (HT) extensively hydrolysed both meat protein extracts, producing peptide hydrolysates with significant in vitro antioxidant and ACE inhibitor activities. The hydrolysates retained bioactivity after simulated gastrointestinal hydrolysis challenge. Gel permeation chromatography sub-fractionation of the crude protein hydrolysates showed that the smaller peptide fractions exhibited the highest antioxidant and ACE inhibitor activities. OFFGEL electrophoresis of the small peptides of both hydrolysates showed that low isoelectric point peptides had antioxidant activity; however, no consistent relationship was observed between isoelectric point and ACE inhibition. Cell-based assays indicated that the hydrolysates present no significant cytotoxicity towards Vero cells. The results indicate that HT protease hydrolysis of meat myofibrillar and connective tissue protein extracts produces bioactive peptides that are non-cytotoxic, should be stable in the gastrointestinal tract and may contain novel bioactive peptide sequences.
Keywords: 2,2′-Azobis(2-amidinopropane) dihydrochloride (AAPH) (PubChem CID: 1969); ACE inhibitor; Antioxidant; Bioactive peptides; Bovine; Captopril (PubChem CID: 44093); Fluorescein (PubChem CID: 16850); Hippuric acid (PubChem CID: 464); Hippuryl-l-histidyl-l-leucine (PubChem CID 94418); Meat hydrolysates; Trolox (PubChem CID: 40634).
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