Impact of high-intensity ultrasound on the development of phytosterol-based oleogels

Abstract

Oil structuration offers an alternative to high saturated fats and has gained significant attention over the past decade. Phytosterols present a promising option as oleogelators due to their low saturated fat content and health benefits. However, they struggle to effectively structure liquid oils at low concentrations. High-Intensity Ultrasound (HIU) has shown potential to enhance oleogels physical properties through cavitation. This study aims to use phytosterols to create oleogels in rapeseed oil, both with and without HIU, and assess their physical properties. Commercial sterols (10 %w/w) were mixed with rapeseed oil. One sample served as a control without HIU, while others were treated with HIU at various amplitudes and durations. After 24 hours at 20°C, samples were analyzed for microscopy, oil binding capacity, melting behavior, polymorphism, hardness, viscosity, and viscoelasticity. HIU produced a single melting peak, reduced crystal size, and decreased oil loss. It also enhanced hardness, viscosity, and viscoelasticity, with significant improvements observed primarily in samples sonicated for longer durations (10 s), regardless of amplitude. The most notable results were from a 10 s pulse treatment (5 s ON/5sOFF/5sON) at 50 % amplitude, which maintained the oleogel stability for 30 days without phase separation. Thus, HIU is a viable, eco-friendly method to enhance phytosterol oleogels physical properties, allowing for effective oil structuration.