Development of low-calorie organogel from sn-2 position-modified coconut oil rich in polyunsaturated fatty acids

Abstract

Coconut oil rich in medium-chain saturated fatty acids was enzymatically modified at the sn-2 position with polyunsaturated fatty acids from fish oil by trans-esterification reaction. The modified coconut oil was combined with gelators (γ-oryzanol and β-sitosterol) to prepare organogels. The effects of different modified coconut oil contents and γ-oryzanol:β-sitosterol ratios on thermodynamic and rheological properties, and microstructures of organogels, as well as their relationships, were studied. The results showed that the addition of gelators increased the hardness, solid fat content, and oil binding capacity of organogels. In addition to its highest melting point and enthalpy change, the organogel containing γ-oryzanol:β-sitosterol (6:4) had the best texture properties that closely resemble the crystalline structure properties. Moreover, the developed organogels had the properties of a pseudoplastic fluid, as described by the power law equation. Gʹ of organogel was found to be significantly higher than Gʹʹ, which indicates that the organogel remains in solid state. The analysis of crystal morphology showed that the crystal of organogels were clusters, consisting of dense three-dimensional network of gel.