Emulsifying and surface properties of citric acid deamidated wheat gliadin

The properties of citric acid deamidated wheat gliadin (D-gliadin) and D-gliadin emulsions at concentrations of 2% and 0.5% at pH 7 and 3 were investigated. D-gliadin exhibited high solubility at neutral pH and had a different molecular weight distribution compared with control gliadin. Stability of D-gliadin emulsion increased after heat treatment. Heat treatment led to a red shift of the fluorescence emission maxima of emulsions, indicating the rearrangement of D-gliadin molecules and increase of the protein structure flexibility at the oil water interface. The emulsion was sensitive to NaCl up to 150 mM due to electrostatic screening effects. D-gliadin concentration influenced the droplet size and the saturation surface load of emulsion. D-gliadin slowly adsorbed on the oil water interface during the adsorption process. Higher D-gliadin concentration exhibited higher surface pressure. Surface adsorption properties confirmed that D-gliadin was a good emulsifier in oil water emulsions. (C) 2013 Elsevier Ltd. All rights reserved.