Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2024
Publication Date: 5/3/2024
Citation: Hwang, H., Kim, S., Moser, J.K. 2024. Unsaturation and polar compounds of vegetable oils affect the properties of sunflower wax oleogels. European Journal of Lipid Science and Technology. https://doi.org/10.1002/ejlt.202300205.
DOI: https://doi.org/10.1002/ejlt.202300205

Interpretive Summary: Oleogels are gels made of vegetable oils or fish oils, which have drawn great interest as replacements of conventional unhealthy fats in foods such as margarines, spreads, and shortenings. Although physical properties such as firmness and melting behaviors are important for the application of oleogels in food products, the effects of the kind of oils and components in them on the physical properties of oleogel were not well understood. A few studies reported contradictory results, presumably, due to different gelling agents, experimental conditions, and different amounts of minor components in oils. Therefore, a systematic study was conducted with twelve vegetable oils and sunflower wax (SW) as a gelator to understand the effects of oils and their components on the properties of SW-oleogels. Minor components, which were presented at the concentrations of 1.87-8.44 % in these oils, were removed from oils, and oleogels were also prepared with these oils to understand the properties of oleogels without the effect of the minor components. Although there were some exceptions and therefore, further studies are needed to understand better, the following general trends were found. Minor components negatively affected the gel strength and lowered the stability of SW crystals. In general, oils with higher unsaturation had lower gel strength. Higher viscosity of oil increased the strength of oleogels, and the melting temperature of oleogel increased with increasing unsaturation of oil. Crytal shape and size of SW were almost identical for all the oleogels in this study and were not the factors affecting gel strength. The information obtained from this study is valuable for fundamental understanding on the factors affecting properties of SW-oleogels and for the development of healthy food products from these oleogels.

Technical Abstract: Previous studies on the effects of unsaturation and polar compounds of oils on the physical properties of oleogels reported inconsistent results. In this study, a systematic study was conducted with twelve vegetable oils with and without polar compounds to understand these effects on the properties of 3 and 7% sunflower wax (SW) oleogels. In general, oils with higher unsaturation produced oleogels with lower gel strength. This relationship may be attributed to the viscosity of oils, which had a negative correlation with unsaturation of oils. Polar compounds in oil negatively affected the gel strength and lowered the melting enthalpy of oleogels indicating that they decreased the crystallinity of SW crystals. The platelet shape of SW crystals was almost identical regardless of the kind of oil. Solid fat content values were similar across the oleogel samples with twelve different oils. This study enlightens several factors affecting the physical properties of SW-oleogels.