Ethylcellulose has been recently shown to be an excellent organogelator for vegetable oils. The resulting gels maintain the fatty acid profile of the vegetable oil used, but posses a solid-like structure that can be useful for the replacement of saturated fats in food products. Texture profile analysis and the back extrusion technique were used to assess the mechanical properties of canola, soybean, and flaxseed oil oleogels consisting of 10% ethylcellulose and 90% vegetable oil. Oils with a higher degree of unsaturation were shown to produce harder gels. Oleogels containing ethylcellulose of three molecular weights and reduced polymer concentrations from 4–10% ethylcellulose were also tested using the back extrusion technique, resulting in an increase in gel strength as polymer concentration and molecular weight increased. Therefore, oleogel strength was shown to be dependant on polymer molecular weight, concentration, and the fatty acid composition of the vegetable oil. Scanning electron microscopy was also used to provide a greater understanding of the gel's microstructure. In addition, frankfurters were made using canola oil oleogels to assess the possibility for replacement of the more highly saturated animal fat in such a product. Cooked frankfurters made with oleogels showed no significant differences in chewiness or hardness compared to the control products made with beef fat. These results provide the first in-depth characterization of ethylcellulose oleogels, and could potentially aid in the design/manufacture of ethylcellulose oleogels with specific textural properties to replace saturated fat in a variety of food products.

Fat-structured food materials are an important component of our diet. The role that fat plays in material functionality, flavor perception, texture and health characteristics is due in large part to its physical properties. An understanding of these physical properties is relevant from scientific, technological and medical perspectives. The physical properties of fat materials, are, in turn, governed by a complex confluence of the various structural levels in a fat material beginning with triglyceride molecules. The formation of nanoscale structural elements by these molecules is the first step in the formation of a fat material as we know it. This review shows how these microstructural elements can be imaged and characterized. It is also shown that the formation of these nanocrystals is affected by the attendant crystallization parameters. Through simulation and a discussion of van der Waals forces, it is shown that these nanoscale elements assemble into colloidal aggregates with fractal character. The influence of microstructure on the mechanical properties of a fat material is explained using a variety of mechanical models. Lastly, this review examines methods by which the properties and characteristics of the various structural levels can be engineered. Shear has been shown to affect the polymorphism and phase transition kinetics of triglyceride crystals. As well, shear has been shown to modify the aggregation of nanocrystals, with consequences for the porosity and diffusivity of oil through the fat crystal network.

We have successfully gelled ethyl cellulose (EC) in different vegetable oils. This work investigated the molecular interactions responsible for such gelation process. Rheological measurements show that flaxseed oil gels need a larger yield force than soybean and canola analogues. We have used both Raman and IR spectroscopy to elucidate which functional groups are involved in the gelation process. We have found that the glycerol group of the triglycerides behaves in the same way in the free oil as in the gel. This is an indication that the specificity seen by using different oils is not due to electrostatic interactions involving this functional group. Our results show that the conformation of the lipid chains is mainly responsible for solvent–solvent interaction. However, the difference seen in the rheological properties is explained in terms of polymer–solvent interactions. These are influenced by the molar volume of the solvent, which is dependent on the amount of unsaturations, such that the larger volume leads to an increased separation of the polymer strands and a decrease in the number of tie points in the polymer network.