In edible fats such as margarine, there is a growing need to develop products that do not contain fatty acids that pose a health risk, such as trans-fatty acids and saturated fatty acids. Therefore, the use of plant wax oleogel has come into the spotlight. Although the study of oleogels for edible use is extremely active, there is still no example for commercial use as foods in all over the world due to poor taste and texture, and also insufficient information on metabolic safety and physical stability.
By the way, the U.S. Food and Drug Administration (FDA) has approved the use of candelilla wax (hereinafter abbreviated as “CLX”) as an edible gelling agent as GRAS (generically recognized as safe). In addition, several vegetable waxes have been submitted for use as gelling agents in edible oleogel products. Based on the above, the development of food products including margarines and shortenings using oleogel is expected to progress even more markedly in the future. Furthermore, emulsifiers are expected for controlling the crystallization of gelling agent. The purpose of this study is to clarify the addition effect of emulsifiers for oleogel crystallization behavior. The samples were prepared with 5% of CLX as a gelling agent, canola oil as a liquid oil, and sucrose fatty acid esters as an emulsifier. It has also been GRAS certified by FDA. A total of five samples were prepared by adding 0%, 1%, and 20% emulsifiers into the gelling agent. The required amount of ingredients was placed in a centrifuge tube, heated and stirred in a hot water bath at 80-100°C for 20 minutes, and then cooled in an incubator set at 20°C, and stored for 24 hours. As for experiments, polarized light microscopic observation, DSC measurement, and needle penetration measurement were performed on these samples.
Polarized light microscopy showed that samples with 20% emulsifier (hereinafter referred to as “the emulsifier (20%)”) was observed to crystallize fine crystals. Furthermore, DSC measurements showed that the emulsifier (20%) increased the crystallization temperature compared to the case of no emulsifier (0%), indicating an accelerated nucleation tendency. Generally, the formation of microcrystals results in the formation of a strong oleogel, but needle penetration measurements showed that the emulsifier (20%) increased the needle penetration value, i.e., decreased the hardness, resulting in a softer texture. In DSC measurements, the exothermic peak was decreasing gradually with a long tail in the sample with the emulsifier (20%), which would indicate that crystal growth occurred slowly, which was a tendency to inhibit crystal growth. According to the three results introduced above, in conclusion, the emulsifier (20%) promoted nucleation, on the other hand, retarded the crystal growth.