The Effect of High Power Ultrasound on the Milk Homogenization Efficiency and Milk Fat Globule Size Compared to Conventional Homogenization

Abstract

Milk fat globule size significantly affects the quality of dairy products, especially sensorial and rheological properties. For this reason, homogenization process is applied in the production of many dairy products to reduce milk fat globule size. In this study, the effect of ultrasonic homogenization application at 4 different power (90W, 180W, 300W and 400W) for 15 minutes on milk fat globule size and homogenization efficiency compared to conventional single stage homogenization at 150 bar pressure and two stage homogenization at 150/50 bar pressure was examined. Dv 0.99, Dv 0.90 and Dv 0.50 volumetric diameter values in micrometer (µm) and milk fat globule sizes in nanometer (nm) by laser diffraction devices and homogenization efficiency values in percent of the milk samples homogenized by different methods were determined. Microscopic imaging of milk fat globules was also performed in all milk samples. The ultrasound process was found more effective in reducing milk fat globule diameters than both single stage and two stage conventional homogenization. The efficiency in the reduction of milk fat globule diameters increased with the increase in the power of the ultrasound process and the maximum reduction in fat globule size was determined at 400W ultrasound application for 15 minutes.