Preparation of a multilayer antibacterial film and its application for controlling postharvest disease in temperate fruit (including apple, pear, and peach) under ambient storage

The objective of this study was to provide formulation of a new multilayer antibacterial film and to investigate the optimal use concentration of chitosan and carboxymethyl cellulose in the range from 0.5% to 2%, as well as its application for controlling postharvest disease in temperate fruit (apple, pear, and peach). The multilayer antibacterial film used chitosan (CS) and carboxymethyl cellulose (CMC) as polysaccharide macromolecule, lemon essential oil (LEO) as active agent, and ε‐polylysine (ε‐PL) as the main antibacterial ingredient. The results showed that the physical properties of the self‐assembled film were adjusted by the electrostatic layer‐by‐layer (LbL) deposition. Fourier transform infrared (FT‐IR) analysis and thermogravimetric (TGA) revealed that hydrogen bonds were generated during the self‐assembly of CS‐LEO/CMC‐ε‐PL film, resulting in changes in intermolecular interactions and thermal stability. Furthermore, compared with CS‐LEO single‐layer film, the multilayer film exhibited higher retention rate of LEO. In vivo test, the self‐assembled film significantly inhibited the infection of postharvest pathogenic fungi including Penicillium expansum (P. expansum) and Alternaria alternata (A. alternata) on fruit. To summarize, the CS‐LEO/CMC‐ε‐PL LbL self‐assembly coating notably controlled postharvest pathogen rot on fruit, and reduced the loss of fruit during storage and transportation. Our results suggest that the polysaccharide‐based edible coating prepared in this work may offer an alternative to synthetic waxes.