Influence of the polarity of the water phase on the mesomorphic behaviour and the α-gel stability of a commercial distilled monoglyceride

The lyotropic mesomorphic behaviour of a commercial distilled monoglyceride based on fully hydrogenated palmstearin at a concentration of 25% was studied as a function of temperature. Differential scanning calorimetry and wide angle X-ray diffraction were used to determine the Krafft temperature. Polarized light microscopy and small angle X-ray scattering were used to analyze the lamellar dispersion to an inverted bicontinuous cubic phase transition. The addition of a polar solvent, namely ethanol, propylene glycol and glycerol shifted the lamellar dispersion region to lower temperatures. The composition of the water phase also played an important role in the stability of the α-gel that was obtained by cooling the lamellar dispersion. In fact, the stability of this metastable phase as expressed by the coagel-index determined by differential scanning calorimetry was negatively influenced by decreasing the water phase polarity.