The influence of the type of oil phase on the self‐assembly process of γ‐oryzanol + β‐sitosterol tubules in organogel systems. Issue 3 (1st February 2013)

• Record Type: Journal Article
• Authors: Sawalha, Hassan; Margry, Giel; den Adel, Ruud; Venema, Paul; Bot, Arjen; Flöter, Eckhard; van der Linden, Erik
• Is Part Of: European journal of lipid science and technology. Volume 115:Issue 3(2013:Mar.)
• Page Start: 295
• Page End: 300
• Publication Date: 2013-02-01
• Subjects: Oils and fats, Edible -- Periodicals; Lipids -- Periodicals; 660.63
• DOI: 10.1002/ejlt.201100395
• Languages: English
• ISSNs: 1438-7697

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Mixtures of γ‐oryzanol and β‐sitosterol were used to structure different oils (decane, limonene, sunflower oil, castor oil, and eugenol). The γ‐oryzanol and β‐sitosterol mixtures self‐assemble into double‐walled hollow tubules (∼10 nm in diameter) in the oil phase, which aggregate to form a network resulting in firm organogels. The self‐assembly of the sterol molecules into tubules was studied using light scattering and rheology. By using different oils, the influence of the polarity of the oil on the self‐assembly was studied. The effects of temperature and structurant concentration on the tubuler formation process were determined and the thermodynamic theory of self‐assembly was applied to calculate the change in Gibbs free energy (Δ<italic>G</italic>⁰), enthalpy (Δ<italic>H</italic>⁰), and entropy (Δ<italic>S</italic>⁰) resulting from the aggregation of the structurants was determined. The self‐assembly was found to be enthalpy‐driven as characterized by a negative Δ<italic>H</italic>⁰ and Δ<italic>S</italic>⁰. A decreasing polarity of the oil promotes the self‐assembly leading to formation of tubules at higher temperatures and lower structurant concentrations.</p> </abstract>