Fabrication and Characterization of Plant Sterol-plant Wax-based Binary Oleogels: Impact of Composite Gelator Composition on Nonlinear Viscoelasticity and Crystallization Behavior

• Multi-scale analysis reveals synergistic gelation mechanism in sterol-wax systems. • Optimized composites form stable β and β′ coexisting crystal polymorphs. • LAOS demonstrates structural destructibility and shear-thinning for fat replacement. • Plant-based strategy integrates nutritional benefits with tailored textural properties. To overcome the mechanical deficiencies of single-component plant sterol-based oleogels, binary composite systems using β-sitosterol (SS) and stigmasterol (STG) with rice bran wax (RW) or candelilla wax (CW) were developed. The effects of component type and ratio on oleogel structures, rheology, and crystallization were systematically evaluated. Results indicated that plant waxes primarily drive gel network formation, whereas optimal plant sterol incorporation induces synergistic enhancements. Specific mass ratios improved oil-binding capacity, hardness, and linear viscoelasticity. Fourier-transform infrared spectroscopy and X-ray diffraction analyses revealed that the optimized STG-wax oleogels formed a stable three-dimensional network characterized by hydrogen bonding and interwoven alkyl chains, with a crystal structure comprising coexisting β and β′ polymorphs. Differential scanning calorimetry thermal analysis further confirmed the synergistic stabilizing effect of the composite systems from a thermodynamic perspective. The large-amplitude oscillatory shear measurements revealed that oleogels possess the necessary structural destructibility and shear-thinning behavior for use as fat substitutes. Specifically, the 4STG:6CW system exhibited a prominent elastic response, whereas the 2SS:8RW system exhibited the highest structural stability. This study demonstrated the synergistic gelation mechanism of sterol-wax systems across molecular to macroscopic scales. By establishing correlations between microstructure and macroscopic rheological properties, it provided essential theoretical support for the rational design of fat substitutes that integrate nutritional benefits with tailored textural properties.