Lysozyme-based composite membranes and their potential application for active packaging

Abstract Barrier packaging materials are significant in protecting the packaged contents from damage caused by oxygen, fogging, fats and oils in the environment. In this study, an active barrier packaging composite based on lysozyme and plastic films including polyethylene (PE) and biaxially oriented polypropylene (BOPP) were designed. The barrier packaging composites were prepared using a layer-by-layer self-assembly process to deposit lysozyme onto the surface of the plastic films. The bulk structure and morphology of the composites were investigated using X-ray photoelectron spectroscopy and atomic force microscopy. The barrier properties of the packaging composites were analyzed by measuring water vapor permeability, oil permeability, oxygen permeability, light transmittance and chromaticity. The results showed that the lysozyme coating greatly reduced the water vapor permeability, oxygen permeability and oil permeability of the packaging without affecting the appearance of the original packaging films. The barrier properties of the packaging composites were strengthened by increasing the number of coated lysozyme layers. The composite films showed effective antibacterial activity against E. coli and S. aureus during a pasteurized milk storage experiment, indicating a promising application prospect.