Microstructure and rheology of cellulose bead-filled whey protein isolate oleogels

This study investigated the oleogelation of cellulose bead dispersions in a sunflower oil oleogel made with solvent-transferred whey protein isolate. The microstructure and rheology of the mixed gels depended on the ratio of hydrated cellulose beads to proteins (9:1, 8:2, 7:3, and 1:1). Two gel stabilization mechanisms were identified. In gels dominated by cellulose beads, capillary bridging and the avoidance of the continuous oil phase dominated network formation. With increasing protein content, the cellulose beads became covered by a layer of aggregated protein, leading to a protein-dominated network. All mixed gels displayed similar elastic behaviour. Oil release was greater in the gels at the highest cellulose bead to protein ratio, which aligned with the presence of void spaces in the network visible under the microscope. These findings serve as the foundation to explore other particle-filled oleogels for use in food-related applications.