Development and characterization of high-performance macadamia oil-based oleogel emulsions

Macadamia oil is rich in monounsaturated fatty acids and bioactive compounds, making it highly valued in the food industry. However, its high fluidity and susceptibility to oxidation limit its broader applications. This study utilized macadamia oil as a base material to develop highly stable oleogels incorporating a β-sitosterol/γ-oryzanol (BS-GO) composite system. The gelation threshold was identified at 6 %, while oleogels prepared with 7 % -12 % BS-GO exhibited a dense three-dimensional network structure, transitioning the oil into a solid state. The oleogel at the optimized 12 % BS-GO concentration demonstrated a hardness of 6283.96 g, an oil-binding capacity of 99.51 %, and significantly enhanced antioxidant capacity, with DPPH scavenging activity reaching 1922.18 μmol TE/100 g. Emulsions derived from these oleogels revealed that emulsifier type significantly influenced stability. Emulsions stabilized with whey protein isolate achieved the smallest droplet size (256.86 nm) and the highest zeta potential (-32.93 mV). The 7 % BS-GO emulsion exhibited remarkable stability under thermal treatment (30-80 °C), freeze-thaw cycles, and varying ionic strengths (0-100 mmol/L). Furthermore, this emulsion effectively inhibited oxidation, with peroxide values ranging from 7.07 to 12.67 mmol/kg and TBARS values between 2.83 and 4.96 μmol/kg during accelerated storage. This research provides a theoretical foundation and practical guidance for the high-value utilization of macadamia oil and the advancement of oleogel-based emulsions in the food industry.