Plasmin-digest of β-lactoglobulin with antibacterial properties

The objective of the present study was to identify the antibacterial properties of plasmin digest of β-lactoglobulin (PDβ). After enzymatic treatment, PDβ was fractionated using reversed-phase high-performance liquid chromatography. The antibacterial activity of plasmin, β-lactoglobulin, PDβ, fractionated peptides and nisin as a control was tested against pathogenic (Escherichia coli and Staphylococcus aureus) and probiotic (Lactobacillus casei and Lactobacillus acidophilus) bacteria. Four antibacterial peptides, βL1, βL2, βL3 and βL5, PDβ and nisin as a control revealed antibacterial activity against pathogenic and probiotic bacteria tested. Finally, the identification of the antibacterial peptides was carried out using LC-Mass. Four antibacterial peptides showed molecular masses of 673.116, 819.320, 916.407 and 2410.515 Da, respectively. Two identified antibacterial peptides were βL1 and βL3, which corresponded to residues 78–83 and 83–91 of bovine β-lactoglobulin. The results showed that PDβ as a source of antibacterial peptides can be considered for controlling bacterial contamination.