Use of High-Intensity Ultrasound to Change the Physical Properties of Oleogels and Emulsion Gels

The objective of this work was to evaluate the effect of high-intensity ultrasound (HIU) on the physical properties of a soft oleogel (2% of candelilla wax, 2% of monoacylglycerol, and 2% of hardfat) and of water-in-oil (W/O) emulsion gels (EG) with various amounts of water (0%, 5%, and 25%). Physical properties of these systems such as thermoresistance, microstructure, melting profile, hardness, rheology, and oil loss were measured. When HIU was applied to the oleogel for 3 min using a 3.2 mm-diameter tip at an amplitude of vibration of 216 μm, a reduction in crystal size and crystal area (P < 0.05) was observed with an increase in hardness and no change in G′ nor in oil loss compared to the nonsonicated oleogel. Other sonication conditions (lower power levels, shorter durations, and bigger tips) tested in this study reduced the hardness and elasticity of the sample and increased oil loss. When HIU (3.2 mm-diameter tip, 216 μm, 3 min) was used in emulsions, harder and more elastic (P < 0.05) samples were obtained only in the samples with 25% water. This study shows that the texture of oleogels and EG with 25% of water can be improved by using HIU. The impact of these results is that the fat content of an EG can be reduced by 25% by adding water and HIU can be used to recover the structure lost due to water addition.