Photo-producible and photo-degradable starch/TiO2 bionanocomposite as a food packaging material: Development and characterization.

In current study, starch/TiO2 bionanocomposites were produced by photochemical reactions as a biodegradable food packaging material. Physical, mechanical, thermal and water-vapor permeability properties were investigated. Then, the photo-degradation properties of nanocomposite films were studied. This is the first report of the photo-producible and photo-degradable bionanocomposite as a food packaging material. Film-forming solutions were exposed to ultraviolet A (UV-A) for different times. Our results showed that UV-A irradiation increased the hydrophobicity of starch films. With increasing UV-A exposure time, tensile strength and Young's modulus of the specimens were decreased. On the other hand, elongation at break of the films was increased with increasing UV-A irradiation. The glass transition temperature and melting point of the films were increased by increasing UV-A exposure time. Nevertheless, the results showed that photo-degradation properties of photo-produced starch/TiO2 nanocomposite were significantly higher than virgin starch and virgin starch/TiO2 films. According to obtain results and bibliography a schema was developed to describe the mechanism of photo-production and photo-degradation of starch/TiO2 by UV-A ray. It can be concluded, the modification of starch based biopolymer by UV-A and nano-TiO2, is an easy and accessible process to improve the packaging properties and photo-degradability of biopolymer based films.