Effect of dielectric properties of lipid matrices on the structure of organogels made with saturated monoglycerides

An emerging strategy to design healthier fatty foods is the substitution of the plastic structure made of saturated fats with unsaturated oils solidified thanks to molecules forming self-assembly networks. These novel fats have been called organogels that are self-standing, thermoreversible, anhydrous, viscoelastic materials structured by a three dimensional supramolecolar network of self-assembled molecules. Literature data highlighted that the structuring properties of these molecules could be affected by the polar characteristics of both oils and structuring agents. However, few data are available on the effect of the dielectric properties of oils and their mixtures on organogel structure. The aim of this research was to study the effect of the dielectric properties of different vegetable oils on the structure of organogels containing saturated monoglycerides (MG). The latter were used as structuring agents. To this purpose, different oils (i.e castor oil, cod liver oil, corn oil, extra virgin olive oil, flax-seed oil, peanuts oil and sunflower oil) were considered. The dielectric constant, dielectric loss and conductivity of oils, oils added with monoglycerides and organogels containing different oils as a function of frequency were determined. At the same time, hardness, microstructure and thermal properties of the organogels were measured. Results highlighted that the self-assembly properties of the structuring molecules resulted affected by the lipid source dielectric properties. These results could have interesting practical applications in the light to design organogels with different mechanical properties by changing the lipid type.