Influence of sodium soap and ionic strength on the mesomorphic behavior and the α-gel stability of a commercial distilled monoglyceride

The lyotropic mesomorphic behavior of a commercial distilled monoglyceride based on fully hydrogenated palmstearin at a concentration of 25% was studied as a function of temperature. Polarized light microscopy and small angle X-ray scattering were used to determine the lamellar dispersion to bicontinuous cubic Im3m phase transition. The addition of sodium soap based on palm oil shifted this transition to higher temperatures. In contrast, by increasing the ionic strength of the water phase the formation of the cubic structure was promoted. Electrostatic interactions also played an important role in the stability of the α-gel that was obtained by cooling the lamellar dispersion. The stability of this metastable phase as expressed by the coagel-index determined by differential scanning calorimetry was positively and negatively influenced by increasing sodium soap concentration and ionic strength, respectively.