Evaluation of the effect of corn starch film composed of Ag-TiO₂ nanocomposites and <i>Satureja khuzestanica </i>essential oi on the shelf-life of chicken fillet

Abstract

Nowadays it seems necessary to replace synthetic plastics with biodegradable films in food packaging due to their major threats to human health and the environment. In this study corn starch film composed of Ag-TiO₂ nanocomposites and Satureja khuzestanica essential oil (SEO) were prepared and the antimicrobial, morphological, physical, and mechanical characteristics in chicken fillet packaging were assessed. The morphology of the films was investigated by scanning electron microscopy (SEM). The combination of energy-dispersive X-ray spectroscopy (EDX) with SEM analyzed the near-surface elements. The plain film showed higher WVP (2.82×10־⁷ g/m.h.Pa) than other films and the nano/essence film had the lowest moisture content% (21.6%). For determining the film's antimicrobial activity, chicken fillets were inoculated with Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus (separately with four prepared films). Microbial counting of the fillets was performed at three intervals (14 and 7th day) and the results showed a significant difference in reducing the number of microorganisms in nano/essence and essence films compared to the control group (chicken fillets packed in plastic bags) and plain film (at a rate of 1.5-2 log CFU/g). The rate of reduction of S. aureus was higher compared to S. Typhimurium and E. coli in the packing groups respectively. Sensory properties were also evaluated at three- intervals. The bio-polymer film incorporated with SEO and Ag-TiO₂ nanocomposites can be used for packaging foods and is able to delay microbial and physical spoilage in foodstuffs.