Effect of different oleogelation mechanisms on physical properties and oxidative stability of macadamia oil-based oleogels and its application

Abstract

In this study, macadamia oil-based oleogels were prepared with four low molecular weight oleogelators: beeswax (BW), monoglyceride stearate (MG), rice bran wax (RBW), and a mixture of γ-oryzanol and β-sitosterol (SO). The physicochemical properties of these oleogels were evaluated by polarized light microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, texture and rheological analysis. Results indicated that the van der Waals force and hydrogen bond interaction existed mainly in MG- and SO-based oleogels, while only van der Waals force interaction observed in RBW- and BW-based oleogels. SO-based oleogels presented superior hardness, oil binding ability and oxidative stability, attributed to the formation of strong polymer network structure. Additionally, all four oleogels demonstrated stable crystal structures and solid-state shear-thinning fluid behavior, with SO-based oleogels displaying higher viscosity. Meanwhile, the feasibility of oleogel as a substitute for cocoa butter (CB) was explored, found that all of oleogels proved effective substitutes for CB in chocolate preparation. The rheological parameters of the oleogel-based chocolates, except for 50%BW oleogel, fell within the range of Casson plastic viscosity and yield stress for chocolate, and exhibited excellent heat tolerance. The results provide a novel strategy for utilization of macadamia oil and the development of heat-resistant chocolate.