Professor Toronto Metropolitan University Toronto, Canada
Abstract: Oleogelation is a common method to structure oil that relies on the formation of self-assembled crystalline or fibrillar networks that entrap liquid oil, forming a thickened liquid or self-supporting semi-solid. One key impediment to their uptake by the food industry is their stability against breakdown following incorporation of food powders such as sweeteners or proteins. The particle surfaces may deplete oleogelator concentration in solution through adsorption, potentially disrupting the formation of the percolated network necessary for structure development, or alter crystal morphology, making them less suitable to bind oil. An alternative means of oil structuring is via the formation of capillary bridges between particles dispersed in oil using small amounts of water forming a 3D percolated particle network that immobilizes particles, effectively gelling, liquid oil. We propose the development of a hybrid method of oil structuring that exploits particle surface properties to control network microstructure and rheology. Our aim is to sequester the particles in an aggregated capillary network and gelation of the resulting oil domain. Our model system combines oleogels made with a model wax as oleogelator (hexatriacontane) and capillary suspensions of surface-modified glass beads with with either hydrophilic or hydrophobic surface character. The compositions herein tested consist of 33 wt% particles, up to 9 vol% water, 2 wt% wax with the remainder being canola oil. We demonstrate that surface molecular interactions dictate capillary network formation, microstructure, and oleogelation. We show that nonpolar particles form weaker networks, resulting in a pourable gel. Polar particles form stronger self supporting networks with G′ independent of microstructure. Both particle types disrupt wax oleogel network formation. The elasticity and firmness of the hybrid material varies depending on the composition, allowing access of materials with a library of textures that range from pourable materials to self-supporting gels.
