Edible wheat gluten (WG) protein films

Commercial wheat gluten (WG) films, hard wheat gluten films and soft wheat gluten films, plasticized with glycerol have been cast from water–ethanol solutions. The effect of aging on various film properties has been investigated. The films were aged for about 6 months at 50% relative humidity and ~25 °C, and the mechanical (tensile strength and the percentage of elongation at break (E _b)), thermal (TG and DSC) and Attenuated Total Reflectance (ATR)-FTIR spectral properties have been studied. Changes in the protein structure were determined by ATR-FTIR spectroscopy. Films from soft WG exhibited the highest E _b (508%) and the highest TS (6.33 MPa). The TG analysis results show that the moisture content in all three kinds of WG protein films is about 5%. The absence of the glycerol phase transition in DSC curves implies that there is no separate phase containing glycerol in the WG protein-glycerol films with 40% glycerol.