Design of active packaging based on chitosan/polyvinyl alcohol containing carbon nanoparticles produced from onion peel to increase the shelf life of red meat

Abstract

Abstract Background: Food, especially meat products, are exposed to physical, chemical and microbial hazards during storage. Active films containing antimicrobial and antioxidant compounds are used to improve quality, increase shelf life and control pathogens. In the present study, active packaging based on chitosan/polyvinyl alcohol containing carbon nanoparticles produced from onion peel was investigated to increase the shelf life of red meat during 20 days of storage. Material and Methods: To confirm and ensure the performance of the synthesized carbon dot films and nanoparticles, light absorption and fluorescence responses and particle size tests were performed with UV-vis spectrophotometer, fluorescence spectrophotometer, and DLS device for nanoparticles. Chitosan/polyvinyl alcohol films containing carbon dot were prepared by casting method. The properties of transparency, solubility, water vapor permeability, and tensile strength and elongation to elongation of the films were evaluated. In addition, the effects of the films on physical, mechanical properties and microbial tests using E. coli and S. aureus bacteria on red meat were performed at 4°C for 0, 4, 8, 12, 16, and 20 days. Results: The results of mechanical and chemical tests of the films showed that carbon nanoparticles with a size of 3 mm and appropriate uniformity were synthesized and by adding them to the film matrix at concentrations of 0.5-4.5%, they exhibited significant compatibility with the synthesized films based on chitosan and improved important physical and mechanical properties by 2% and 6.3%, respectively. Also, the obtained chitosan/polyvinyl alcohol/carbon dot film exhibited significant antibacterial activity (inhibition zone of 17.3 mm for E. coli and 18.3 mm for S. aureus) and high antioxidant properties (free radical inhibition of 56.5% in the DPPH method and 58.9% in the ABTS method). The optimal concentration of carbon dot was also obtained as 2% after conducting the

necessary tests for use in film production. Conclusion: This study showed that the film containing carbon nanoparticles obtained from onion peel as a new compound can be used as a suitable option for active food packaging and to increase the shelf life of red meat by inhibiting bacterial growth and improving some physical-mechanical and chemical properties of chitosan/polyvinyl alcohol film. Keywords: Active packaging, chitosan, polyvinyl alcohol, carbon nanoparticles, onion peel extract.