Edible wheat gluten films: influence of the main process variables on film properties using Response Surface Methodology

An edible wheat gluten film was developed and effects of gluten concentration, ethanol concentration (ET) and pH of the film-forming solution on various film properties were evaluated using Response Surface Methodology. pH and ethanol concentration had strong interactive effects on film opacity, water solubility and water vapor permeability. A simultaneous variation of ethanol concentration and pH between 32.5% ET, pH 4 and 45% ET, pH2 resulted in homogeneous and transparent film with relatively low water solubility. The lowest water vapor permeability would be expected with 20% ethanol concentration and pH 6. Mechanical properties were mainly affected by gluten concentration and pH. The most resistant film was obtained at high gluten concentration (12.5%) and pH 5