Characterization and antibacterial activity of edible films based on carboxymethyl cellulose, Dioscorea opposita mucilage, glycerol and ZnO nanoparticles.

The edible films composed ofcarboxymethyl cellulose (CMC), glycerol, mucilage from Chinese yam (DOM)and ZnO nanoparticles (ZnO-NPs), were prepared by a casting method. To evaluate the applicability for food packaging, prepared films were characterised morphological, physical, rheological, mechanical and barrier properties, performed FT-IR, thermal analysis, and finally investigated the antibacterial activity and acute oral toxicity of films. The surface of films presented irregular arrangement with nanoparticles combined in the networks, suggesting the best "CMC to DOM weight ratio" of approximately 1:1 could provide a smooth surface. The films with 2.0 g ZnO-NPs presented antibacterial effects against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. With the increase of DOM, the antibacterial rate dropped at 400 and 450 μL/mL. The film-forming solutions with higher ZnO-NPs content display shear-thinning properties and liquid-like behaviour. The edible films have a great potential to be used in application in food packaging.