Influence of epichlorohydrin modification on structure and properties of wheat gliadin films

The present study was to examine influence of epichlorohydrin (ECH) modification on structure and properties of glycerol-plasticized wheat gliadin films casting from ethanol/water (70/30 v/v) solution. The modified films were characterized using proton nuclear magnetic resonance ((1)H NMR), Fourier transformation infrared (FTIR) spectra, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Water resistance (moisture absorption MA, water vapor permeability WVP, and weight loss in water WLW), tensile mechanical properties (Young's modulus E, tensile strength sigma(b), and elongation at break epsilon(b)), and thermal decomposition behavior were evaluated in relation to ECH content. Experimental results revealed that ECH modification gave rise to marked reduction in WLW and significant improvements in E and sigma(b), which were accompanied by slight variations in MA, WVP, and thermal decomposition temperature. The improvements of E and sigma(b) were related to the formation of a partially cross-linked protein network even though the modification led to reductions in percentages of the hydrogen bonded NH groups and the beta-sheet structure.