Biodegradable nano composite film based on modified starch-albumin/MgO; antibacterial, antioxidant and structural properties

Abstract In this study, an antibacterial/antioxidant film based on modified starch and albumin was prepared in which magnesium oxide nanoparticles (MgO) at concentrations of 0 to 5 w/w% were used to improve the physicochemical properties of biopolymers. For this purpose, various modified starch/albumin films containing magnesium oxide nanoparticles (S-A-MgO) were synthesized based on the D-Optimal experimental design. Thickness, moisture content, water solubility, water vapor permeability (WVP) and antioxidant properties were analyzed for 19 films prepared according to the statistical design. Then, the antimicrobial properties and structure of films was evaluated using FTIR, SEM, XRD, and TGA techniques. The results of the tests showed that with the addition of magnesium oxide nanoparticles, the thickness of the produced films increased, moisture content, water solubility and water vapor permeability decreased. The use of magnesium oxide nanoparticles in nanobiocomposite films increased antioxidant activity. Morphological images (SEM) of the produced films showed a rough and heterogeneous surface in films containing magnesium oxide nanoparticles compared to films without nanoparticles. The results of FT-IR indicated that there was no new bond between the starch-albumin functional groups and MgO and the physical presence of MgO nanoparticles in the polymer matrix was confirmed. XRD results showed that in films containing MgO nanoparticles, a wide peak of about 2θ=16.5 ° formed, indicating their relative amorphous structure. In investigating the antibacterial effect of films containing nanoparticles, halos with a diameter of about 4-6 mm against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was formed, which showed the antimicrobial properties of the prepared films.