Preparation of starch/PVA/Cu-NPs bio-nanocomposites in packing as preservation of UF soft cheese.

This study represents the biosynthesis of copper oxide nanoparticles (CuO-NPs) via bacteria and their utilization in the synthesis of a bio-nanocomposite based on starch (St) and polyvinyl alcohol (PVA) to be applied in preserving ultrafiltration (UF) soft cheese. The bio-nanocomposites were synthesized by blending St/PVA with a ratio of 4:1 wt, wt and loaded with various concentrations of CuO-NPs (0, 20, 40, and 80 mg) to obtain bio-nanocomposite coatings S1, S2, S3, and S4, respectively. The coatings' mechanical strength, water and oxygen barrier quality, morphology, and crystallinity were all studied. The chemical composition, microbial load, total solids, and pH changes for uncoated and coated cheese samples that were stored at 5 ± 2 °C for 60 days were evaluated. Results showed that films loaded with CuO-NPs significantly improved the mechanical and barrier properties of the prepared films, in addition to reducing the moisture loss and microbial growth and extending the shelf life of the coated cheese. In addition, the bio-nanocomposite coating loaded with higher CuO-NP concentrations (S3 and S4) showed superior antimicrobial effects, indicating their potential as active edible coatings for cheese preservation.