Development of Brazil Nut Oil-Based Oleogel and Emulsion Gel: A Comparative Study of Structural and Physicochemical Properties.

In this study, Brazil nut oil (BNO) was structured either as oleogels (OG) using carnauba wax (CW) or as emulsion gels (EG) using gelatin at water:oil ratios of 1:1, producing systems intended as models for solid fats. The effects of structuring methods and different gelling agent concentrations were comparatively evaluated in terms of their structural, physicochemical, and thermal properties. Visual analysis demonstrated that BNO can be effectively structured with 6% CW, while 2% gelatin was sufficient to induce the transition from liquid oil to a semi-solid material. Polarized light microscopy (PLM) revealed distinct structural organizations contributing to their respective structural stability, with crystalline structures in OG and emulsion-filled networks in EG. Regarding oil binding capacity (OBC), it increased significantly with higher CW concentrations, rising from 30.63% ± 1.34% (BOG2) to 83.65% ± 1.90% (BOG10) (p < 0.05). Between EG samples, all OBC results were statistically similar, reaching approximately 100% oil retention (p < 0.05). DSC analysis revealed not only a higher melting onset but also greater enthalpy for BEG (491.5-726.8 J/g) compared to BOG (1.5-17.8 J/g), demonstrating superior thermal stability and network organization of gelatin-based gels. Furthermore, rheological tests showed that BEGs exhibited a stable linear viscoelastic region (LVR) (G' > G″ up to >12% strain) and a higher crossover point (∼100%), indicating greater structural strength than BOGs. These findings provide a foundation for future studies exploring their potential use as models for solid fats.