Effect of pH and plasticizer concentration on the properties of faba bean protein isolate based edible film

The objectives of this study were to investigate the potential of faba bean protein isolate (FPI) in preparation of an edible film and to determine the effects of film forming solution pH and plasticizer concentration on film properties. So film samples were prepared in three different pH levels (7, 9 and 12) and plasticizer concentrations (40, 50 & 60% w/w protein isolate). Results showed that increasing of pH improved mechanical properties (tensile strength and elongation) and solubility of films but caused water vapor permeability (WVP) and lightness of films to decrease. Plasticizer concentration did not affect WVP over the studied range. Elongation and solubility of films increased and tensile strength decreased by increasing of plasticizer content of film forming solutions. The lowest WVP and the highest tensile strength was observed at pH 12 and 40% (w/w of FPI) glycerol concentration.