Preparation of soluble starch/zinc oxide nanocomposites by solid-phase reaction and study of their antibacterial properties

Soluble starch/zinc oxide nanocomposites could be promising candidates for eco-friendly antimicrobial, food packaging, and a wide range of other utilization. In order to find a new way for the preparation of this kind of nanocomposites, an efficient and energy-saving reaction for the synthesis of soluble starch/zinc oxide nanocomposites has been investigated. The reaction was implemented in a solid state at room temperature without post-reaction calcination. In this process, the starting materials were ZnSO₄·7H₂O and KOH, while KCl served as the matrix and soluble starch was used as the surfactant. The prepared nanocomposites were characterized by Fourier infrared spectroscopy, X-ray diffraction spectrum, transmission electron microscope, scanning electron microscope, dynamic light scattering, and ultraviolet-visible absorbance spectroscopy. In addition, the UV-blocking effect and antimicrobial capability of the prepared nanocomposites were determined. The results showed that the nanocomposites were composed of soluble starch and ZnO nanoparticles. The mean diameter of ZnO nanoparticles was 12 nm. The results also showed that the suspension composed of nanocomposites were superior to that composed of simple zinc oxide nanoparticles in stability and inhibition of Escherichia coli and Staphylococcus aureus.