Effect of curcumin incorporation on the structural and functional properties of oleogels structured with rice bran or carnauba wax

Oleogels have been effective in substituting saturated fat and serving as a delivery of bioactive compounds. This study investigates the physicochemical properties of rice bran wax (RBW) and carnauba wax (CNW) oleogels in response to curcumin (CUR) incorporation. A total of 40 oleogel formulations were prepared using 2%, 4%, 6%, and 10% wax (RBW or CNW) loaded with 0%, 0.1%, 0.2%, 0.4%, or 0.8% curcumin. The samples were characterized through visual analysis, polarized light microscopy (PLM), oil binding capacity (OBC), textural properties, differential scanning calorimetry (DSC), and oxidative stability (PV) tests. Significant differences ( p < .05) were observed across formulations in oil retention, textural properties, and oxidative stability. Among all tested formulations, 6% RBW and 10% CNW with 0% (RB6CR0 and CN10CR0) and 0.4% curcumin (RB6CR4 and CN10CR4) exhibited the highest oil binding capacity (∼100%) and oxidative stability. The PV of samples RB6CR0, CN10CR0, RB6CR4, and CN10CR4 were ≤366.33 meq/kg over 28 days of storage. Curcumin showed antioxidant effect in oleogels. For example, the PV of CN10CR1 (0.1% CUR) and CN10CR8 (0.8% CUR) was 151.00±2.64 and 84.33±3.51 meq/kg ( p < .05) at day 14, respectively. Further, visual tests and textural properties analysis showed that those oleogels had great physical stability as saturated fat substitutes. These findings demonstrate that oleogels can function as structurally stable carriers for curcumin while maintaining desirable physical properties for food applications. This study advances the development of healthier lipid alternatives and strengthens the potential of oleogels as effective bioactive delivery systems in functional food formulations. • Rice bran wax oleogels form a stronger network with increasing wax concentration. • Carnauba wax oleogels exhibit a structural shift only at 10% concentration. • Curcumin incorporation reduces physical stability, even at constant wax levels. • Curcumin enhances oxidative stability of wax-based oleogels for food applications.