Oxidative and physical stability of vegetable oil oleogels with a binary mixture of beeswax and candelilla wax

Authors: Hwang, Hong-Sik; Kim, Sanghoon

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2025
Publication Date: 6/24/2025
Citation: Hwang, H., Kim, S. 2025. Oxidative and physical stability of vegetable oil oleogels with a binary mixture of beeswax and candelilla wax. Journal of the American Oil Chemists' Society. https://doi.org/10.1002/aocs.12965.
DOI: https://doi.org/10.1002/aocs.12965

Interpretive Summary: Solid fats are needed to provide desired textural properties to food products such as margarine, spread, shortening, frosting, and other related products. However, due to their high contents of saturated fats, these fats are associated with health problems including raised LDL cholesterol concentrations, hypertension, and cardiovascular disease. Therefore, increasing efforts are being made to find alternatives to conventional solid fats. So far, one of the most promising candidates is oleogels (or organogels), which are prepared with a small amount of gelator added in vegetable oil or fish oil. These oleogels contain more unsaturated fatty acids than conventional solid fats, which are beneficial to human health. Several oleogels having physical properties similar to conventional solid fats have been developed. Especially, our research group has recently developed oleogels with binary wax systems (mixtures of beeswax and candelilla wax) that have higher gel strength and melting point closer to conventional solid fats than those with one wax. However, their oxidative and physical stability during storage has not been studied. In this study, the binary wax oleogels were prepared with olive oil, soybean oil, and flaxseed oil, and their oxidative and physical stability was evaluated during storage at 4°C for 180 days and at 25°C for 90 days. These oleogels had comparable oxidative stability to a conventional sold fat sample (margarine fat) during storage. Gel strength of oleogels and the margarine fat gradually decreased during storage. The decrease in gel strength of these oleogels was slower than that of the margarine fat sample at 25°C while it was faster at 4°C. Melting properties did not significantly change during storage. Overall results indicated that the binary wax oleogels had oxidative and physical stability comparable to margarine fat while some adjustments may be required for more stringent requirements or harsher storage conditions.

Technical Abstract: Oxidative and physical stability of 3 and 7% beeswax-candelilla wax (BW-CDW, 1:1) oleogels prepared with flaxseed (FSO), soybean (SBO), and olive oils (OO) were evaluated during storage at 25 and 4°C. Peroxide values (PV) and conjugated diene values (CDV) of BW-CDW oleogels were lower than bulk oils after storage at 4°C for 180 days, and those of 7% wax oleogels were lower than 3% wax oleogels indicating the protection effect by oleogelation. In contrast, these oleogels had lower oxidative stability than bulk oils at 25°C indicating the prooxidant activity of waxes. PV of 7% BW-CDW SBO oleogel increased slower than commercial margarine fat (CMF) at both storage temperatures while its CDV increased faster at 25°C. Gel strength (firmness and cohesiveness) of oleogels decreased at both temperatures. Gel strength of CMF decreased faster than oleogels at 25°C while it was steady at 4°C. Gel strength of OO oleogels dramatically decreased during storage at 4°C, which was likely due to large oil crystals formed that broke the wax crystal network at 4 °C. Solid wax content and melting enthalpy of oleogels increased indicating that new crystals formed during storage, which, however, did not provide higher gel strength. New spherulite crystals appeared during storage at 4°C, which might be the reason for decreased gel strength. Overall results indicated that BW-CDW oleogels had the oxidative and physical stability comparable to CMF except for OO oleogels stored at 4°C.