Professor Toronto Metropolitan University Toronto, Canada
Abstract: There is continued interest in the oleogelation of vegetable oils in response to the shift in consumer demand for processed foods with a lower saturated fat content. While most strategies to date have focused on strategies to gel bulk oils, foods often contain a dispersed particulate phase that must also be immobilized in a continuous oil phase. The present work investigated the structuring of model dispersions of hollow glass beads (30-60 wt%) in sunflower oil using protein aggregates based on whey protein isolate prepared via a solvent exchange procedure. Structuring of the oil dispersion was contingent on promoting particle-particle interactions between the protein oleogelator and the dispersed particles, which was achieved by addition of 2 wt% water to the protein-dispersion mixture. Modulating the ratio of glass beads to lyophilized solvent-modified proteins (1:10, 1:4) increased gel strength and resistance to oil separation compared to the oleogel controls. Microstructure analysis showed that apart from capillary bridges, protein hydration and swelling were also responsible for stabilization. The conclusion of this study was that addition of water could structure oil dispersions of glass beads via capillary forces, despite the tendency for particles to hydrate with water. The work presented outlines a protocol for the oleogelation of particle dispersions in oil using whey protein isolate.
