Preparation of Active Nanocomposite Film Consisting of Sodium Caseinate, ZnO Nanoparticles and Rosemary Essential Oil for Food Packaging Applications

Active films based on sodium caseinate (SC) were fabricated via the casting method; these films were reinforced with zinc oxide nanoparticles (ZnO NPs) and rosemary essential oil (REO). The films' optical, mechanical, and barrier and antimicrobial properties were evaluated. Further characterization was done using SEM, XRD, and FTIR spectroscopy. The results disclosed that the incorporation of ZnO NPs and REO into the SC matrix significantly improved the mechanical and barrier properties as well as moisture resistance of the SC film. The simultaneous incorporation of ZnO NPs and REO considerably reduced the water vapor permeability (WVP) of the films but increased their flexibility and strength. The microscopic and spectroscopic characterization revealed that the additives were highly compatible with the SC film matrix given the formation of uniform and homogeneous composite films. The nanocomposite films also exhibited noteworthy antimicrobial activity against the tested bacteria. In summary, this type of biopolymer-based active film can be considered as a promising material for food packaging applications.

Automated summary

The incorporation of zinc oxide nanoparticles and rosemary essential oil into sodium caseinate matrix significantly improved the mechanical and barrier properties of the films, reduced water vapor permeability, and increased flexibility and strength. Microscopic and spectroscopic characterization revealed high compatibility of additives with the film matrix, forming uniform and homogeneous composite films with noteworthy antimicrobial activity. These biopolymer-based active films show promise for food packaging applications.