Organogelation of extra virgin olive oil with fatty alcohols, glyceryl stearate and their mixture

The final properties of organogels based on a mixture of gelators can be tuned by taking advantage of interactions between gelators. In this work, extra virgin olive oil was structured using glyceryl stearate (GS), policosanol (P) and their mixtures aiming at investigating their effects on the rheological properties and microstructure of obtained gels. Rheological tests evidenced that P yields a more consistent material with higher crystallization and gelation temperatures with respect to GS. Gels based on a mixture of gelators exhibit intermediate properties between those of “pure” gels, even though closer to those of P organogels. The crystallization and gelation phenomena in mixed gels seem to be dependent only on policosanol fraction, whereas dynamic moduli are affected by both gelators. Intermolecular interactions were investigated with FT-IR finding that GS is able to give hydrogen bonding whereas P works mainly through the formation of van der Waals interactions. Mixed gels exhibit a behavior close to that of P gels, even though van der Waals interactions seem less evident than in pure P gels. As a consequence, from a macroscopic point of view, the use of the mixture yields a weaker gel than that obtained with the same concentration of pure P.