Antimicrobial film based on polylactic acid coated with gelatin/chitosan nanofibers containing nisin extends the shelf life of Asian seabass slices

Abstract

Mixed gelatin/chitosan solutions incorporated with nisin at varying levels were electrospun on polylactic acid (PLA) films. Electrospinning of gelatin/chitosan solution performed at a constant voltage of 20 kV with a feed rate of 0.5 mL/h resulted in the formation of nanofibers (GC-NF) with diverse morphologies as indicated by the SEM images. Bead formation was visible in the nanofiber network as nisin concentration in the electrospinning solution augmented. PLA films coated with GC-NF exhibited antibacterial activity, particularly against gram-positive bacteria. When GC-NF coated PLA film containing nisin at the selected level (0.4 %), which had the highest antibacterial activity, was characterized, it had decreased water vapor permeability but enhanced mechanical properties (p < 0.05). Characteristic peaks of functional groups in gelatin, chitosan, nisin, and PLA films coated with nanofibers were confirmed using Fourier transform infrared (FTIR) spectroscopy. Storage bags prepared from PLA films coated with GC-NF and 0.4 % nisin retarded the microbial and chemical deterioration of Asian seabass slices over the refrigerated storage of 12 days at 4 ℃. Overall, PLA film coated with GC-NF incorporated with nisin could be a potential active packaging alternative for food applications.