Development of chitosan/hydroxyethyl cellulose bionanocomposite films enriched with raisin extract and zinc oxide for antimicrobial food packaging applications

Abstract Bionanocomposite films comprising chitosan (CS), hydroxyethyl cellulose (HEC), raisin extract (RE) and different ratios of zinc oxide nanoparticles (ZnO-NPs), namely CS/HEC/RE/ZnO bionanocomposites, were formed via casting method. The structural, morphological, mechanical and physical properties of the produced CS/HEC/RE/ZnO bionanocomposite films were characterized using SEM (Scanning Electron Microscope), EDX (Energy Dispersive X-ray), FT-IR (Fourier Transform-Infrared), and UV-Vis (Ultraviolet-Visible) spectrometry. The anti-microbial activity also was assessed against six different strains. The incorporation of ZnO-NPs improved film thickness and swelling ratio, while decreased water solubility properties of the matrix. Concerning the mechanical properties, 4.0% ZnO-NPs exhibited the best elongation at break and tensile strength. In the SEM micrographs, increasing ZnO-NPs content exhibited higher population of white spots and caused a more even, dense, compact, and homogenous film structure. CS/HEC/RE/8%ZnO revealed the highest UV absorbance with a clear peak at 350 nm indicating the incorporated ZnO-NPs. Concerning the antimicrobial activity, CS/HEC/RE/8%ZnO demonstrated the highest antibacterial activity against S. Typhamirum and E. coli . Additionally, CS/HEC/RE/8%ZnO exerts the best antifungal activity against C. albicans with inhibition zone of 23 mm. In conclusion, the acquired bionanocomposite films have excellent structural, morphological, mechanical, and biological properties nominating them for flexible food packaging materials.