Fabrication and characterization of chitosan-titanium dioxide nanocomposite film as ethylene scavenging and antimicrobial active food packaging

Active packaging from nanocomposite of chitosan and nanosized titanium dioxide (TiO2) to be used as an ethylene scavenging and antimicrobial film was developed. Chitosan films containing different TiO2 concentrations (0, 0.25, 0.5, 1 and 2% w/w) were fabricated and characterized for structural, mechanical, optical and barrier properties. The scanning electron microscope images showed that TiO2 nanoparticles evenly distributed in the chitosan film matrix. However, the spontaneous agglomeration of the TiO2 was observed at high TiO2 concentrations. The X–Ray diffraction patterns presented that crystallinity of TiO2 in the nanocomposite films increased with TiO2 concentration. The Fourier transform infrared spectra indicated that there were hydrogen bonding and O-Ti-O bonding between TiO2 and chitosan, which affected the tensile strength, elongation at break, and water vapor barrier properties of the films. The chitosan-TiO2 nanocomposites exhibited ethylene photodegradation which increased with increasing TiO2 concentration. Based on tensile strength, water barrier and ethylene photocatalytic degradation properties, chitosan film containing 1% TiO2 (CT1) was found to be optimal and hence was selected for antimicrobial evaluation. The results suggested that the CT1 exhibited antimicrobial activity against Gram-positive (Staphylococus aureus) and Gram-negative (Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa) bacteria and fungi (Aspergillus and Penicillium).