Preparation and properties of chitosan–soybean trypsin inhibitor blend film with anti-Aspergillus flavus activity

The chitosan-based blend films were prepared from chitosan, soybean trypsin inhibitor extract (STI)/wild soybean trypsin inhibitor extract (WTI) and glycerol (Gly) solutions, the properties of which were also investigated, including thickness, mechanical property, water vapor transmission, optical transmittance, and solubility. In addition, the resulting films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The result of SEM images showed the surface and cross-section of chitosan–STI/WTI–Gly blend film had more smooth and dense morphology than pure chitosan film, which suggested there was a better compatibility among the three components. XRD and FTIR spectra indicated that the possible interaction force among the components might be the hydrogen bonds of NH⋯OC and OH⋯OC. Furthermore, the antifungal activity against A. flavus by the prepared blend films had been investigated. The facts that the germination and growth of A. flavus were strongly inhibited by chitosan–STI/WTI–Gly film indicated the blend films might be useful as potential bio-control packaging against A. flavus during the peanuts and other cereals storage.