Effect of β-sitosterol and palmitic acid mass ratio on structural, physicochemical, and rheological properties of rice bran oil-based oleogel

Edible oil-based oleogels provide a viable and healthier alternative to traditional saturated fats. This study aimed to develop oleogels using rice bran oil combined with β-Sitosterol (Sit) and Palmitic Acid (PA). Structural, physicochemical, and rheological properties of the prepared oleogels were investigated. The results showed that Sit alone was insufficient to create a stable oleogel. However, when Sit was combined with PA, a firm and stable oleogel was obtained. The gel network was formed and stabilized through physical non-covalent interactions such as hydrogen bonding. Additionally, x-ray diffraction analysis indicated that the oleogel molecules rearranged and underwent a homogeneous polycrystalline transition due to the different gelator combinations, revealing the coexistence of β and β′ crystal types in the oleogels. Moreover, the firmness and oil binding capacity of the oleogels increased with higher PA content in the gelator mixture. Furthermore, the storage modulus (G′) and loss modulus (G″) were frequency-independent, with G′ significantly higher than G". The results suggest that fat-like oleogel can be produced using a combination of Sit and PA at mass ratios of Sit2:PA3 or Sit1:PA4 (w/w). • Combining β-sitosterol and palmitic acid in rice bran oil produced a stable oleogel. • Stable gel network formation relied on physical interactions, not covalent bonds. • Oleogels with Sit and PA showed β and β′ crystal type coexistence. • Increasing the PA content enhanced the oleogel's firmness and oil-binding capacity. • Oleogels exhibited frequency-independent rheological properties.