and Pepsin at 37 °C for 30, 60 and 90 min. Degree of hydrolysis, angiotensin-I-converting enzyme (ACE) inhibitory activity and antimicrobial activity of each hydrolysate against Gram-negative (Escherichia coli, Salmonella enteritidis) and Grampositive (Staphylococcus aureus, Listeria innocua) bacteria were studied. Results showed that the degree of hydrolysis for all enzymes was in the range of 2.63–3.36%. Electrophoresis profiles of the Kilka protein hydrolysates showed that most of produced peptides were in the range of 30 D but Alcalase and Neutrase had a better performance in the production of low molecular weight peptides in the range of 10 D. This led to increase the antimicrobial activity against the examined bacteria at the concentration of 200 μg/mL peptide solution. The Neutrase enzyme produced hydrolysate with the highest ACE inhibitory activity (53% ± 1.8 at 500 μg/mL). Antimicrobial activity of Kilka protein hydrolysates using Protamex and Pepsin was lower than the others due to lack of considerable amount of small peptides. The current research has demonstrated that the peptides derived from the enzymatic hydrolysis of Kilka fish protein in optimum conditions are capable of being converted to antimicrobial and antihypertensive agents to be used in functional foods.

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