Improved mechanical and antimicrobial properties of zein/chitosan films by adding highly dispersed nano-TiO2

Highly dispersible TiO 2 nanoparticles were prepared through the hydrolysis of titanium alcohol, and a series of TiO 2 -modified zein/chitosan (CS) films were prepared through a process involving blending, solution casting and evaporation. The mechanical properties and the antibacterial capacity of the zein/CS/TiO 2 films were characterized to explore the effects of different TiO 2 nanoparticle contents. Results showed that the addition of nanoscale TiO 2 remarkably improved the mechanical properties and thermal stability of the zein/CS/TiO 2 film. The tensile strength of the zein/CS/TiO 2 films significantly increased (p<0.05) with the increasing TiO 2 loadings in films, reaching a maximum of 28.33 ± 1.53 MPa at 0.15 wt % TiO 2 nanoparticles. The antibacterial effect of the composite films on Gram-positive bacteria ( S. aureus ) was more significant than that of Gram-negative bacteria ( E. coli and S. enteritidis ), and the antibacterial effect of UV light was better than that of dark conditions. In particular, the inhibition zones of zein/CS/TiO 2 (0.15%) film against E. coli , S. enteritidis and S. aureus under UV light condition increased by 21.78%, 21.45%, and 26.44%, respectively, compared with the control. This study suggested that adding highly dispersible TiO 2 nanoparticles is an effective method for improving the mechanical and antimicrobial properties of zein/CS films for various applications, such as medical and food packaging.