Gel Phase Nano Formulation: The Effect of Triglycerides

Abstract Gel phase formation is commonplace for surfactants, lipids and oils. The most frequently encountered states are the α-gel phase for non-polar lipids such as triglycerides and the L β phase for surfactants and polar lipids. It is well known that both the L β phase and the α-gel phase consist of surfactant layers where the alkyl chains are mostly in an all-trans conformation with no translational mobility. These are packed in a two dimensional hexagonal lattice with rotational disorder (high angle X-ray peak at 4.2 A). However, in the case of the α-gel phase for unsaturated monglycerides, the alkyl chains cannot be in the all-trans state. The high angle X-ray pattern shows a broad peak at 4.1 A plus at ca. 4.5 A. Clearly, this cannot pack in the same hexagonal structure as the α-gel phase of the saturated lipids, but the cis double bond can be accommodated. Limited information is available regarding the effect of saturated and unsaturated triglyceride on stability of the gel phase in aqueous system We have examined the phase behaviour of mixed saturated and unsaturated monoglycerides [glycerol monostearate (GMS) and glycerol monooleate (GMO) (1:1)] in palm oila and olive oil with water. Optical microscopy was used to study the mesomorphic behaviour as function of temperature. We also employed differential scanning calorimetry (DSC) to determine the transition enthalpies between mesophases. In parallel we use small angle X-ray diffraction to characterize the different mesomorphic phases at different temperatures. The finding of this work cast light on the phase behaviour of saturated and unsaturated monoglycerides in oil with water system, Our results suggest that saturated triglycerides promotes the stability of gel phase while unsaturated triglycerides promotes the forming of the cubic phase at room temperature From an industrial point of view, both the cubic phase and gel phase could be attractive systems for making stable products with low fat content.