Novel Bilayer Emulsions Costabilized by Zein Colloidal Particles and Propylene Glycol Alginate. 2. Influence of Environmental Stresses on Stability and Rheological Properties

Novel bilayer emulsions co-stabilized by zein colloidal particles (ZCPs) and propylene glycol alginate (PGA) were designed to overcome some limitations of conventional emulsions or Pickering emulsions. The bilayer emulsions of various concentrations of PGA (0.01-1.50%, w/v) and different incorporation sequences of ZCPs and PGA (ZCPs/PGA and PGA/ZCPs) were fabricated using the layer by layer (LBL) electrostatic deposition technique. Influence of environmental stresses (pH 2.5-8.5; temperature 60-80 °C ; ionic strength 0-100 mM NaCl) was focused on the stability and rheological properties of the novel bilayer emulsions. In comparison to the Pickering emulsion stabilized by ZCPs alone, bilayer emulsions exhibited improved stability and unique rheological characteristics under environmental stresses. The microstructure of well-defined spheres existing a branchlike network was observed in bilayer emulsions by TEM. A comprehensive evaluation was made of the physical characteristics and stimuli-responsive behavior of bilayer emulsions. The result provided meaningful information for understanding the changing mechanism of rheology of bilayer emulsions under environmental stresses.