β-Sitosterol-Enhanced Walnut Oil Liposomes: Optimization, Stability, and Applications

Abstract

Cholesterol has limitations in food and nutraceutical applications due to health concerns. β-Sitosterol (βS) has become an alternative to cholesterol due to its nutritional characteristics and stability. We optimized βS-stabilized iron walnut oil (IWO) liposomes using a hybrid experimental design (Plackett–Burman and Box–Behnken methodologies), addressing emulsion stability and scalability gaps. Key parameters, including soy lecithin concentration (9 mg/mL), βS/lecithin ratio (1:6), IWO/lecithin ratio (1:4), and ultrasonication conditions (21% Tween-80, 30 min, 425 W), were optimized. The resulting nanoliposomes achieved metrics: 92.51% encapsulation efficiency, 133.9 nm particle size (polydispersity Index [PDI] = 0.25), and −39.93 mV zeta potential, outperforming in thermal, centrifugal, and storage tests. βS synergizes with IWO's antioxidants, acting in dual roles as stabilizer and oxidation barrier, which is unachievable with conventional sterols. This innovation offers a safer and more effective option for food and nutraceutical applications.

Practical Applications: This work delivers scalable strategies for food, nutraceutical applications, and pharmaceutical sectors. β-Sitosterol enables plant-based liposomes to encapsulate bioactive compounds (e.g., iron walnut oil's PUFAs), combining stabilization and oxidation resistance for shelf-life extension without synthetic additives. Optimized parameters ensure reproducible production of stable nanocarriers (133.9 nm, 92.5% efficiency). Cholesterol replacement with phytosterols aligns with clean-label trends, whereas valorizing underutilized IWO fosters economic growth in Southwest China. The technology bridges lab-to-industry gaps, offering cost-effective encapsulation that addresses health priorities (heart-healthy formulations) and environmental sustainability through resource-efficient lipid protection.