A biodegradable bi-layer nano fibrous membrane fabricated by centrifugal spinning for active food packaging

To solve the problem of cytotoxicity for most antimicrobial agents loaded in packaging materials, we developed a novel bi-layer fibrous membrane by using centrifugal spinning, which of the outer layer was submicron native potato starch/polyvinyl alcohol (ST/PVA) composite fibers loaded with ZnO nanoparticles (ZnO NPs) for providing high antibacterial activity. The inner layer was nano-based calcium alginate/polyethylene oxide (CA/PEO) fiber for providing excellent biocompatibility. The addition of ZnO caused the semicrystalline structures of ST/PVA fibers, while the CA/PEO fibers were shown semicrystalline structures due to the PEO. Fourier transform infrared indicated that posttreatment had not effect on the structures of ST/PVA/ZnO fiber, but the structure of CA/PEO fibers were affected by interaction between COO  groups of alginate and Ca 2+ ions. The results of mechanical property demonstrated that CA/PEO fibers showed highest stress of 3.83 ± 0.25 MPa and helpful for improving the stress of bi-layer fibrous membrane. The obtained fibrous membrane had excellent antibacterial property with diameters of bacteriostatic zone against E. coli and S. aureus of 20.5 and 21.5 mm, respectively. On this basis, the shelf life of strawberry was improved up to 6th day by inhibit the growth of microorganisms, which indicated that the obtained fibrous membrane showed great potential for food packaging.