Properties of oleogels formed with high-stearic soybean oils and sunflower wax

Authors: Hwang, Hong-Sik; Gillman, Jason; Moser, Jill; Kim, Sanghoon; Singh, Mukti; Byars, Jeffrey; Evangelista, Roque

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2018
Publication Date: 5/2/2018
Citation: Hwang, H.-S., Gillman, J.D., Winkler-Moser, J.K., Kim, S., Singh, M., Byars, J.A., Evangelista, R.L. 2018. Properties of oleogels formed with high-stearic soybean oils and sunflower wax. Journal of the American Oil Chemists' Society. 95(5):557-569. https://doi.org/10.1002/aocs.12060.
DOI: https://doi.org/10.1002/aocs.12060

Interpretive Summary: Hydrogenated vegetable oils, which are semi-solid at room temperature, have been widely used to provide desired texture to food products such as margarine, spread and shortening. However, the hydrogenation process generates trans fats, which have negative effects on several diseases such as diabetes, some types of cancers, and cardiovascular disease. Therefore, the FDA declared that trans fats are not “generally recognized as safe” (GRAS) in 2013 and mandated food companies to eliminate partially hydrogenated oils by 2018. Due to this regulation, food manufacturers have switched to plant-based highly saturated oils such as palm oil. However, consumption of tropical oils with short chain fatty acids has the similar health issues. In contrast, unlike saturated fats in tropical oils, stearic acid does not negatively affect human health. For this reason, high stearic oils are much more desirable than oils containing other short chain saturated fats. Organogels have also drawn increasing interest as alternatives to trans fats and short chain saturated fats in margarine and spread products. In this study, we made oleogels from two different high stearic soybean oils to examine the feasibility of applying these oleogels in food products. Sunflower wax was used as oleogelator because we found that it showed the strongest gelation ability among other oleogelators tested in our previous study. Firmness, melting behavior, solid fat content, crystal formation, and rheology of these oleogels revealed their great potential as alternatives to unhealthy fats in foods.

Technical Abstract: In an effort to develop alternatives for harmful trans fats produced by hydrogenation of vegetable oils, oleogels of high stearic soybean (A6 and MM106) oils were prepared with sunflower wax as oleogelator. Oleogels of high stearic oils did not have greater firmness than that of regular soybean oil at room temperature. However, the firmness of high stearic oil oleogels at 4 °C sharply increased due to the high content of stearic acid. High stearic acid soybean oils had more polar compounds than regular soybean oil and polar compounds in oil negatively affected the firmness of oleogels. Differential scanning calorimetry (DSC) showed that wax crystals facilitated nucleation of solid fats of high stearic oils during cooling. Polar compounds did not affect the melting and crystallization behavior of wax. Solid fat content (SFC) showed that polar compounds in oil and wax interfered with crystallization of solid fats. Linear viscoelastic properties of 7% SW oleogels of three oils reflected well the SFC values while they did not correlate well with the firmnesses of oleogels. Phase-contrast microscopy showed that the wax crystal morphology was slightly influenced by solid fats in A6.