Production of antibacterial fraction from Atlantic mackerel (Scomber scombrus) and its processing by-products using commercial enzymes

• Atlantic mackerel and its by-products were hydrolyzed using 4 commercial proteases.
• Hydrolysates were rich in essential amino acids as K, L and F (3.44–7.81 mg g−1).
• Protamex, neutrase or papain generated a high number of small peptides (300–700 Da).
• Crude samples (1 mg mL−1) inhibited at least 40% of L. innocua and E. coli growth.
• By-products hydrolysates by papain and neutrase were highly antilisterial (69 and 65%).

Atlantic mackerel and its processing wastes were hydrolyzed separately using four commercial proteases, namely: Protamex, Neutrase, papain, and Flavourzyme. Mackerel and its by-products hydrolysates were rich in essential amino acids such as lysine, leucine and phenylalanine (3.44–7.81 mg g−1). Hydrolysis using protamex, neutrase or papain generated a high number of small peptides (300–700 Da). Both crude hydrolysates of mackerel and its by-products (1 mg mL−1) inhibited at least 40% of Listeria innocua HPB13 and Escherichia coli MC4100 growth, with crude by-products hydrolysate obtained by papain and neutrase being the most antilisterial with 69.7% and 65.2% of inhibition, respectively. Dose-dependent inhibition curves were obtained and complete inhibition of both L. innocua and E. coli was obtained after acetone fractionation of whole mackerel and its by-products hydrolyzed with protamex at 20 mg mL−1. Due to its high nutritional value, coupled with excellent functional properties mackerel by-products are of interest as functional foods.