Effect of plasticizer and antimicrobial agents on functional properties of bionanocomposite films based on corn starch-chitosan for food packaging applications.

The aim of this study was to evaluate the influence plasticizer (glycerol (GLY)/sorbitol (SOR)) and antimicrobial (potassium sorbate (KS)/grapefruit seed extract (GFSE)) agents on crystallinity, water barrier, mechanical, thermal and anti-fungal properties of prepared with corn starch (CS)-chitosan (CH) nanoclay (Na-MMT) bionanocomposite films. Results showed that CS/CH/nanoclay/SOR/GFSE films exhibit a higher crystallinity than any other bionanocomposite films. Molecular miscibility among corn starch, chitosan (COOH, NH) and nanoclay (AlOH, SiOSi) was exhibited in XRD. Films plasticized with SOR showed the highest tensile strength, lowest film solubility, lowest water vapor permeability and thermal stability. Fourier transform infrared spectroscopy (FTIR) confirmed that the main interactions among the components in a bionanocomposite film are due to hydrogen bonding. Bionanocomposite films containing GFSE showed a maximum zone of inhibition against Aspergillus niger. Synthetic plastic films exhibited fungal growth on 6th day whereas CS/CH/nanoclay/SOR/GFSE films did not show the same up to 20 days when bread samples were packed at 25 °C and 59% RH. CS/CH/nanoclay/SOR/GFSE film could potentially be useful for active packaging in extend the shelf life; maintain its quality and safety of food products thus substituting synthetic plastic packaging materials.