Cross-linked gelatin–riboflavin-based film incorporated with essential oils and silver nanoparticle by gamma-irradiation: A novel approach for extending the shelf life of meat

The gamma-irradiation is one of the most acceptable technologies to modify the biopolymer structure by forming a highly energetic electron. The effect of gamma-irradiation for cross-linking of gelatin (G) film in the presence of riboflavin (R) and the physicochemical properties of films were investigated. Different concentrations of R (0.3, 0.75, and 1.2% (w/w) based on the dry weight of G) and 3 doses of gamma-irradiation (5, 10, and 15 kGy) were used. The cross-linked film was incorporated with a mixture of essential oils (EOs) and silver nanoparticles (AgNPs) in order to use as an active packaging for prolonging the shelf life of meat. The results indicated 0.75% R (w/w) and 5 kGy irradiation had a positive effect on the tensile strength, water insolubility, and water barrier properties of the composite G film. Nevertheless, the reduction of film elongation (%), suggests the formation of compact structure and cross-linking through the generation of radicals. The infrared spectroscopy evaluation showed that proper irradiation dosages could produce cross-linking bonds in G film and form a denser network. In vitro and in situ microbial analyses showed that the active film incorporated with EO-AgNPs had antimicrobial activity against most spoilage and pathogenic bacteria and was able to prolong the shelf life of meat by up to 21 days. Therefore, irradiated G-R-EO-AgNP film with good mechanical and antimicrobial properties has the potential to be developed as a biodegradable food packaging material in the food industry.