Edible starch films enhanced using CaCO3 nanoparticles and plasticizers by optimized extrusion-casting process

Edible films (EF) can be produced and developed for preservation of fruits and vegetables. Starch has been considered one of the biopolymers with the greatest potential to produce edible films by different processing techniques such as extrusion-casting. The objetive was to study the effect of calcium carbonate nanoparticles and plasticizers (sorbitol- glycerol (80-20%; w/w)) (by extrusion (EXT)-casting (CT) combination technologies to obtain EF with improved mechanical and barrier properties. Corn starch-plasticizers were processed in a twin screw extruder to produce thermoplastic starch modified followed by the addition of the calcium carbonate nanoparticles (CCNP) in casting to EF formation. A hybrid design (four factors; twenty one treatments) of surface response methodology was used to optimization process. The optimal EF was characterized mechanical and barrier properties and also characterized according to microstructural properties (X-ray diffraction, Scanning Electron Microscopy) to determine the damage caused in the starch during EXT and CT. In conclusion, it is possible to obtain EF with greater both Breaking Strength and Deformation, as well as, lower Water Vapor Permeability and Solubility (mechanical and barrier properties), through the use of CCNP and plasticizers, using EXT-CT combination processes.