Effect of intrinsic and extrinsic factors on the stability of the α-gel phase of a glyceryl monostearate-water system

Glyceryl monostearate-water systems (MG-gels) undergo a polymorphic transition from the alpha-gel phase to the coagel phase. This phase transition results in destabilization and loss of water in monoglyceridestructured systems, commonly found in personal care and food products. In this study, we examined the effect of intrinsic factors (type and concentration of co-emulsifiers) and extrinsic factors (cooling rate and applied shear) on the stability of the alpha-gel phase. The methods used to study the polymorphic transition were differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results suggested that the transition from the alpha-gel phase to the coagel phase caused a change in the gel's physical appearance. More specifically, opaque regions developed in the semi-translucent alpha-gel upon aging. The stability of the alpha-gel phase can be increased by using an alpha-tending co-emulsifier, such as sodium stearyol lactylate (SSL), and by increasing the concentration of the co-emulsifier. Slow cooling rates without shear could also increase the stability of the alpha-gel phase. In this work, we developed a sub alpha Coagel Index that can be used together with the Coagel Index to characterize the degree of polymorphic transformation of MG-gels.