Preparation, characterization, and antibacterial properties of biofilms comprising chitosan and ε-polylysine

Of late, the demand for food-packaging materials, in particular, multifunction packaging materials that are biodegradable; antibacterial; have good mechanical and barrier properties; and are edible and transparent, has increased considerably. In this study, we prepared chitosan (CS)/ε-polylysine (PL) biofilms with different CS-to-PL ratios. We studied the preparation, mechanical properties, microstructures, thermal stability, transparency, water-vapor permeability, oil permeability, and antibacterial properties of the composite CS/PL biofilms. The results demonstrate that CS/PL biofilms are mechanically strong, have good thermal stability, high transparency, low water-vapor and oil permeability, and extensive antibacterial properties that act against Escherichia coli, Bacillus subtilis, and yeast. Therefore, we therefore conclude that CS/PL biofilms are promising food-packaging materials. •Properties of biofilms comprising ε-polylysine (PL) and chitosan (CS) were investigated.•We found that those biofilms for which the weight ratio of PL to CS was 1:2 had good mechanical and barrier properties.•The CS/PL biofilms have broad antibacterial properties against Escherichia coli, Bacillus subtilis, and yeast.