The thermal, rheological, and structural characterization of grapeseed oil oleogels structured with binary blends of oleogelator

Authors: CHOI, KYEONG-OK - Sejong University; Hwang, Hong-Sik; JEONG, SUNGMIN - Sejong University; Kim, Sanghoon; LEE, SUYONG - Sejong University

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2020
Publication Date: 9/12/2020
Citation: Choi, K., Hwang, H., Jeong, S., Kim, S., Lee, S. 2020. The thermal, rheological, and structural characterization of grapeseed oil oleogels structured with binary blends of oleogelator. Journal of Food Science. 85(10):3432-3441. https://doi.org/10.1111/1750-3841.15442.
DOI: https://doi.org/10.1111/1750-3841.15442

Interpretive Summary: Oleogels are very promising alternatives to solid fats containing high levels of saturated fats. Oleogels consist of vegetable oil containing high contents of mono- and polyunsaturated fatty acids that are much more desirable than saturated fatty acids for human health. In an oleogel system, vegetable oil turns into a gel when it is mixed with a small amount of oleogelator with heat and cooled to room temperature. Natural waxes are of great interest as an oleogelator because they are typically inexpensive, widely available, and safe as a food additive. However, one of the problems with natural wax-based oleogels is higher melting point than conventional fats. In this study, we found that the melting point of oleogel was significantly lowered when candelilla wax was mixed with another oleogelator, glyceryl monostearate. It is also desirable to have greater hardness because this means that a smaller amount of gelator can be used to achieve the same physical properties without significantly affecting the sensory properties of foods. Oleogels with these two oleogelators formed stronger gels. Investigation using microscopy showed that when these two oleogelators were mixed, unique crystals were formed to increase the strength of oleogels. From the detailed composition study of commercial glyceryl monostearate, we found that another ingredient, glyceryl distearate, was also played a critical role in the property enhancement. Therefore, our next study will focus on the properties of oleogels with three components to further improve the properties of plant-wax based oleogels.

Technical Abstract: A new eutectic system was established in grapeseed oil oleogel prepared with candelilla wax (CDW) and glyceryl monostearate (GMS) blends at varying mass ratios, and its physicochemical characteristics were characterized in terms of thermal, rheological and microstructural properties. The oleogel with CDW and GMS at a blending ratio of 75 and 25 (CDW-75:GMS-25) exhibited the lowest melting point, implying a eutectic behavior. The CDW-75:GMS-25 oleogel also had a harder texture, greater viscoelasticity, and lower oiling-off characteristics that were highly attributed to its small crystals and dense structural network observed from phase-contrast microscopic images. When GMS from different vendors were examined for melting behavior and hardness of oleogels, it was found that the oleogel properties were highly dependent on the detailed composition of GMS. NMR study showed that the ternary system of CDW, glyceryl 1-monostearate, and glyceryl 1,3-distearate was responsible for the eutectic behavior of the CDW-75:GMS-25 oleogel.