Preparation and characterisation of chitosan/silver nanoparticles nanocomposite films with orange peel extract as active food packaging

The primary purpose of active food packaging is to maintain packaged food's quality, shelf life, and safety. In this study, chitosan (CH)-based nanocomposite films were prepared using the simple solution casting method by incorporating different concentrations of silver nanoparticles (AgNPs) to develop active food packaging. Silver nanoparticles were synthesised biologically using orange peel extract as the reducing agent. The silver nanoparticles were characterised using UV-visible spectrophotometry at 300 nm to 600 nm, which peaked at 400 nm, indicating the formation of nanoparticulate materials. The functional and morphological characterisation of the films was conducted using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The films' organoleptic properties, moisture content, water solubility, absorption, and biodegradability tests were also evaluated. Next, the antibacterial activity of the films was examined against the gram-negative and gram-positive bacteria, Escherichia coli and Staphylococcus aureus, respectively, using the disc diffusion assay. It was found that increasing the AgNPs concentration increased the water solubility but decreased the moisture content and water absorption of the nanocomposite films. The nanocomposite films also showed good biodegradability properties after decomposition for 14 days. The CH/AgNPs nanocomposite film exhibited greater antibacterial characteristics at the highest concentration at the maximum zone of inhibition against E. coli (28.00±1.5 mm) and S. aureus (21.33±1.5 mm). Therefore, the prepared nanocomposite films possess the requisite material characteristics for utilisation as active food packaging to extend the shelf life of foods.