Rheological Behavior of Interfacial Layers Stabilized by Gelatin with Lecithin

The effect of lecithin (natural surfactant) addition to gelatin on the surface rheological properties of the water/heptane interfacial layer and emulsion films formed by these liquids was studied. It was found that the gelatin/lecithin mixtures form complexes in the aqueous phase. Self-assembly of these complexes leads to the formation of viscoelastic interfacial adsorption layers characterized by a yield stress and elastic modules that provide stability of the emulsion films and emulsion systems. The above mentioned parameters evolve in time, though the formation of equilibriuminterfacial layers proceeds during several hours; emulsion bilayer films require only several minutes.