Wax‐Based Oleogels—Properties in Medium Chain Triglycerides and Canola Oil

The non‐triglyceride structuring of liquid oils, so‐called oleogelation, enables new and more beneficial product designs. Natural waxes have proven to be excellent oleogelators due to their wide availability and low inclusion levels. However, waxes vary greatly in their compositions and contain different proportions of major components: wax esters (WE), fatty acids (FA), fatty alcohols (FaOH), and hydrocarbons (HC). In this study six waxes (bees (BW)‐, sunflower (SFW)‐, ricebran(RBW), carnauba (CRW)‐, candelilla (CLW)‐, and sugarcane wax(SCW)) are selected to develop a pairwise assessment regarding the major components. Commercial canola oil, rich in minor and polar components, and medium‐chain triglycerides (MCT), as a “clean” saturated solvent, are used to elucidate the effect of solvent type on the gel forming behavior of 10% w/w oleogels. The gels are analyzed rheologically, penetronomically, microscopycally, and by calorimetry. It can be shown that the solubility and presence of polar minor components are crucial factors in oleogelation. Practical applications: Useful areas of application can be found in products with high proportions of saturated and trans fatty acids, a high potential of substitution, and can for instance include bakery‐, meat‐, culinary‐ and confectionary products

An Attempt to Relate Oleogel Properties to Wax Ester Chemical Structures

Wax esters are considered to have a dominant contribution in the gelling properties of wax-based oleogels. To understand their gelling behavior, oleogels of seven different wax esters (total carbon number from 30 to 46; c = 10% [m/m]) in medium-chain triglycerides oil were characterized. Scanning electron microscopy revealed that wax esters crystallize in rhombic platelets with a thickness of 80 to 115 monomolecular layers. Bright field microscopy showed that the regularity and face length of the crystals increased with the total carbon number and molecular symmetry of the respective wax ester. Oscillatory rheology was used to characterize the gel rigidity (Gmax*). Here, wax ester oleogels with smaller total carbon numbers yielded higher Gmax* values than those of wax esters with higher total carbon numbers. The gel rigidity (Gmax*) inversely correlated with the crystal face length. Smaller and optically less well-defined platelets promoted higher gel rigidities. In the case of the microstructure of a specific oleogel composition being manipulated by a variation in the cooling rates (0.8; 5; 10 K/min), this relationship persisted. The information compiled in this manuscript further elucidates the crystallization behavior of wax esters in oleogels. This contributes to the understanding of the composition–structure–functionality relationship of wax-based oleogels supporting future food applications