Investigation of Antioxidant and Antimicrobial Properties of Nanocomposite Films Containing Synthesis of Silver Nanoparticles with Mentha extract

Today, due to its environmental problems and importance, the use of biodegradable nanocomposite films is of particular importance. In this study, silver nanoparticles were synthesized by means of aqueous extract of Mentha and the adsorption capacity of 1,1-diphenyl- 2-picrylhydrazyl radicals and their antimicrobial activity should investigated by the method of determination of minimum inhibitory concentration. The uniformity and shape were structure of these nanoparticles was determined by scanning electron microscopy. The antimicrobial effect of starch-based nanocomposite films, together with these nanoparticles, was investigated by disk diffusion test and determination of minimum inhibitory concentration of nanoparticles by threeEscherichia coli, Staphylococcus aureus and Listeria monocytogenes. The results showed that silver nanoparticles showed the highest absorption at 430 nm and had a spherical shape and their average size was between 15-37 nm. The silver nanoparticles produced acted as DPPH radical inhibitors (IC50 = 170 μ M). The minimum growth inhibitory concentration and the minimum lethal concentration on Staphylococcus aureus showed 3.1 and 6.2 showed the highest minimum inhibitory concentration. Also, by measuring the diameter of the bright area by the disk penetration test, pure starch does not have antimicrobial properties, but by adding 250 ppm silver nanoparticles to the starch film in the presence of bacteria, a halo with a diameter of 2.55 cm is formed and in fact by adding nanoparticles antimicrobial properties Starch is formed in the film and again increases the diameter of the halo to 2.35 cm in the film by bringing the amount of silver nanoparticles to 500 ppm, which indicates an increase in antimicrobial properties. Starch- based biodegradable films with biosynthesized silver nanoparticles showed antimicrobial effect against all tested microbes (p <0.05).