Unsaturation and polar compounds of vegetable oils affect the properties of sunflower wax-oleogels

Although it is important to understand the factors affecting the physical properties of oleogels for their application in food products, the effects of the kind of oils and components in them are not well understood. Previous studies on the effects of unsaturation and polar compounds of oils on the properties of oleogels reported inconsistent results, presumably, due to different gelling agents, experimental conditions, and different amounts of minor components in oils. In this study, a systematic study was conducted with 12 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. Polar compounds in oil negatively affected the gel strength. Melting and crystallization temperatures increased with increasing unsaturation of oil. The platelet shape of SW crystals was almost identical, regardless of the kind of oil. Solid wax content values were similar across the oleogel samples with 12 different oils. This study enlightens several factors affecting the physical properties of SW-oleogels.

Practical Application: This study provides information about the effects of unsaturation of oil and polar compounds in oil on firmness and melting properties of sunflower wax (SW)-based oleogels. It was found that the firmness of SW-oleogel can be significantly different (up to 65%) depending on vegetable oils used, and it decreased with increasing unsaturation of oil. It was also found that the firmness of the oleogel can be increased by up to 36% by removing polar compounds in oil. Solid wax content (SWC) of oleogels did show meaningful correlations with the firmness of SW-oleogels. All the oleogels examined in this study had very similar shapes and sizes of SW crystals. For practical application, the unsaturation of oil and the polar compound content have to be considered when designing oleogels with desired textural properties.