Study on antibacterial starch/chitosan blend film formed under the action of irradiation

Starch/chitosan blend films were prepared by irradiation of compression-molded starch-based mixture in physical gel state with electron beam (EB) at room temperature. The influence of chitosan and radiation on the properties of the prepared films was investigated. The tensile strength and the flexibility of starch film were improved largely after incorporation of 20% chitosan into starch film. X-ray diffraction and scanning electron microscope analyses of starch/chitosan blend films indicated that there was interaction and microphase separation between starch and chitosan molecules. Furthermore, in order to produce a kind of antibacterial films, the starch/chitosan blend film was irradiated, and the antibacterial activity of the starch/chitosan blend films against Escherichia coli (E. coli) was measured via optical density method. After irradiation, there is no obvious change in the structure of starch/chitosan blend films, but antibacterial activity was induced even when the content of chitosan was only 5% due to the degradation of chitosan in blend films under the action of irradiation.