Fish skin gelatin and chickpea protein isolated (G-CP) edible blend films incorporated with 0.25 and 0.5% copper sulfide nanoparticle (CuSNP) and microencapsulated Nigella sativa essential oil (MNEO) (0.015 and 0.03%, w/w of protein) were prepared and optimized by the response surface methodology based on the central composite design (RSM-CCD). Antimicrobial activity, infrared spectroscopy (FTIR), x-ray diffraction (XRD), morphological characteristics and thermal attributes of composite films were examined. In general, the effect of CuSNPs and MNEO on the properties of blended films, besides their inherent nature, is related to their interactions with the protein matrix and the synergistic effect on each other. As authenticated by the FTIR and XRD, the simultaneous use of CuSNPs and MNEO because of the synergistic effect of CuSNPs on the antibacterial attributes of MNEO and raising the content of antimicrobial components in the blend film expressed the highest antimicrobial functionality against E. coli. and S. aureus. Also, the results of microbiological and chemical tests of packaged minced meat revealed that the simultaneous use of MNEO and CuSNP in the film has a positive synergistic effect in increasing the storage life of minced meat, as compared to the other samples.
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