Chitosan-based film incorporated with silver-loaded organo-bentonite or organo-bentonite: Synthesis and characterization for potential food packaging material

Biopolymer-clay composite films were synthesized and characterized for food packaging material. The synthesis was conducted in two stages. Cetrimonium bromide-modified bentonite (CTAB-bentonite) was first exchanged with Ag ions to obtain Ag-CTAB-bentonite. Biopolymer-clay composite films were then performed by a solution-casting method between chitosan (biopolymer) and Ag-CTAB-bentonite or between chitosan and CTAB-bentonite. Different weights of CTAB-bentonite (3% and 5% wt.) and Ag-CTAB-bentonite (3% and 5% wt.) were used during the second stage. The resultant films were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscope coupled with energy dispersive X-ray spectroscopy, atomic force microscopes, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, optical measurement, and others (moisture content, swelling behavior, water solubility, antibacterial, shredded carrot preservation, and biodegradability). Results indicated that the properties (thermal stability, thermomechanical ability, UV-visible light barrier, shredded carrot preservation) of the chitosan-based film incorporated with the synthesized composites were enhanced compared to those of the CS film. The CS/(CTAB-bentonite)-3% and CS/(Ag-CTAB-bentonite)-3% films exhibited antibacterial properties against Escherichia coli, Salmonella enterica subp. enterica, Staphylococcus aureus, and Listeria monocytogenes. The chitosan-based film reinforced with the two prepared composites can be potential for food preservation and packaging.