Production and Characterization of Nanocomposite Film Based on Whey Protein Isolated/Copper Oxide Nanoparticles Containing Coconut Essential Oil and Paprika Extract

This study aimed to produce a whey protein isolate (WPI) based nanocomposite film containing copper oxide nanoparticles (CuONPs) with coconut essential oil (CEO) (0, 0.4, 0.8% w/v) and paprika extract (PE) (0, 0.03, 0.06% w/v) using a central compound design (CCD). Antioxidant capacity, water vapor permeability, mechanical properties, antimicrobial activity, morphological characteristics Fourier transform infrared (FTIR), X-ray diffraction (XRD), and thermal properties of films were investigated. In addition to the properties of CuONPs, CEO, and PE, this effect was due to hydrogen interactions between them and the biopolymer matrix. As confirmed by the FTIR and XRD, the co-application of PE and CEO due to the synergistic effect of pigment on the antimicrobial properties of CEO and increasing the content of antimicrobial compounds in the film showed the highest activity against Staphylococcus aureus and Escherichia coli. The results of the thermal property analysis of the films showed the formation of a complex between the nanocomposite film with CEO and PE. In summary, the results of the present study showed that nanocomposite films containing the combination of PE and the CEO could be useful in food packaging.