*Overview of Food Antimicrobial Packaging DOI: http://dx.doi.org/10.5772/intechopen.108666*

matrix. However, high concentration of ZnO-chitosan nanoparticles as fillers affected the barrier and mechanical properties negatively. If we consider all of the properties, like mechanical properties, barrier performance, and the antimicrobial effect of the composite films, 3.0 wt% of ZnO-chitosan nanoparticles was proven to be the optimal concentration of the active compound in the biopolymer matrix. Ascorbic acid blended with various biopolymers, such as whey protein, gelatin, and alginate or CuO nanoparticles, were used to prepare nanocomposite films in food packaging applications. CuO-NPs were loaded with ascorbic acid (CuO@Ascor) and incorporated into two different biopolymers, such as chitosan and xanthan gum to form chitosan-CuO@Ascor (A CA) and xanthan gum CuO@Ascor (X CA) to establish and show the antimicrobial activity of wrapping packaging material [74]. The incorporation of the active compounds into the polymer matrix may be performed using the solution casting method or via the melt blending method (to avoid solvents). The first step of melt blending method is a regranulation, but before this process, active compounds have to be mixed with the selected additives, such as plasticizers or compatibilizers. If nanoparticles are used as active agents, selected additives should also be added to prevent agglomeration of the nanoparticles and to provide their uniform distribution into the polymer/biopolymer matrix. Then, polymer/biopolymer pellets must be mixed with the prepared mixture of active compounds with additives. As next step, material has to be extruded with a twin-screw extruder for incorporating an active agent into the polymer/biopolymer matrix. The thermal profile of the process depends on the polymer matrix and on active compounds. To obtain active packaging material, the final, modified, and active pellets must be extruded through a flat die using chill-roll cast film extrusion line or using a film-blowing machine [50, 67]. **Table 1** shows additional examples of bio-nanocomposite films with an antimicrobial activity which may be used in food packaging.
