This presentation will provide an overview of the use of high intensity ultrasound (HIU) to change physical properties of lipids. HIU of 20 kHz frequency was used at different power levels (6-100 W) for short periods of time (2.5-10 sec) in edible fats such as anhydrous milk fat, palm kernel oil, and commercial shortenings. In general, HIU was applied during the isothermal crystallization of the lipid and the crystallization behavior and physical properties of the crystalline network formed was measured using polarized light microscopy, rheology, texture profile analyzer, and differential scanning calorimetry. Results show that HIU can be used to induce lipid crystallization with reduction of induction times from 35 min to 20 min for anhydrous milk fat crystallized at 28 �C. The induction in crystallization resulted in the formation of a crystalline network with small crystals.  In addition, harder and more elastic materials (increases in the order of 200-2,000%) with sharper melting profiles were obtained with the use of HIU. In general no significant effect on the amount of crystalline material obtained after 90 min of crystallization was observed as a consequence of sonication suggesting that smaller crystals obtained by HIU are responsible for generating a harder and more elastic material.  The application of HIU to lipid samples did not change their triacylglycerol composition or their oxidative stability measured using peroxide value. The effect of HIU to change the physical properties of lipids was more significant when low supercoolings (or highertemperatures) and higher power levels were used and when the sonication was applied close to the onset of crystallization. These results demonstrate that HIU can be used as an additional processing tool to modify the crystallization behavior of lipids and to tailor the functional properties of the material.

High intensity ultrasound as a novel technology to change the physical properties of lipids

248th National Meeting (2014)

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