Film-forming mechanism and heat denaturation effects on the physical and chemical properties of pea-protein-isolate edible films

Pea-protein isolate solutions were heat-denatured and dried to form stand-alone edible films. Heat treatment at 90 degreesC over 5 min increased tensile strength and elongation-at-break, and decreased the elastic modulus. No significant differences were found in the initial contact angle of water and surface energies of heat-denatured films from those of nonheated films except for the 20 min heat-treated film. Additionally, heat denaturation reduced the water absorption rate of the films to 19 to 40% of the nonheated film. FTIR spectroscopy showed that more water existed in the nonheated films as compared to the heat-denatured films. Electrophoresis studies suggested that intermolecular disulfide bonds were created during heat denaturation, which resulted in increased film integrity.