Abstract: In order to improve the dispersibility of nano-SiO2 in potato starch films and consequently to enhance the packaging and preservation properties, potato starch nanocomposite films were prepared by two cycles of ultrasonication. The optimization of the concentrations of nano-SiO2, potato starch and glycerin was conducted using the orthogonal array method. The prepared films were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and ultraviolet-visible (UV-vis) spectroscopy. The effect of packaging with the films on reactive oxygen metabolism in the white button mushroom Agaricus bisporus during storage at (4 ± 1) ℃ was determined. The results showed that ultrasonication resulted in uniform dispersion of nano-SiO2 in the films. The films with exhibited the optimal properties at a potato starch concentration of 3.5 g/100 mL, a glycerin concentration of 3 g/100 mL and a nano-SiO2 concentration of 0.3 g/100 mL. The XRD and FTIR analyses confirmed that the ultrasonic in-situ synthesis method could result in the formation of strong hydrogen bonding between nano-SiO2 and starch molecules. The composite films had outstanding anti-UV property. The properties of films were enhanced by ultrasonic in-situ synthesis compared to the routine method, as indicated by a reduction in water vapor transmission rate, oxygen permeability and water solubility of 30.22%, 71.16% and 39.61%, respectively, and an increase in tensile strength of 17.82%. The films prepared in this study could control reactive oxygen metabolism, thereby extending the shelf-life of Agaricus bisporus.

Key words: ultrasonic, potato starch nanocomposite films, dispersity