The objective of this study was to investigate the synergistic effect of nano titanium dioxide (TiO2-N) and Mentha piperita essential oil (MEO) on the equilibrum moisture sorption isotherm and microbial growth rate of Staphylococcus aureus of cassava starch film. For this purpose, cassava starch biocomposite film with the addition of 1, 3 and 5% TiO2-N and 1, 2 and 3% MEO, and glycerol as a plasticizer were obtained by the casting method. The equilibrium moisture absorption isotherm and antibacterial activity of prepared nanobiocomposite films against Staphylococcus aureus were examined. The obtained results demonstrated that by addition of nanoparticles and essential oil to the starch biocomposites, the equilibrium moisture absorption isotherm curve was shifted to lower moisture content. The microbial tests stated that the pure cassava starch film (control) showed no antibacterial activity against the Staphylococcus aureus and the antibacterial activity significantly increased with increasing concentration of both TiO2-N and MEO in the starch films (p<0.05). However, the antibacterial activity of TiO2-N nanoparticles was higher than MEO. Addition of TiO2-N and MEO increased lag phase and decreased log phase in microbial growth curve. Finally, according to the obtained results in this study, it can be concluded that incorporation of TiO2-N and MEO combination improved the antibacterial activity of cassava starch biocomposites against Staphylococcus aureus and these bionanocomposite films can be used for packaging and extending the shelf life of food products.

Keywords: Bionanocomposite, Cassava starch, TiO2 nanoparticles, Peppermint

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