Ultrasonic separation of milk to select for fat globule size distribution

Abstract Text: The size of fat globules is important in manufacturing dairy products such as cheese and butter.   Smaller fat globules result in a smooth texture and mouthfeel in cheese, while butter production better utilizes larger globule sizes.  Although the cream separator is most commonly used in dairy processing operations to separate cream from milk, centrifugal technology is not commonly used for selecting for a specific fat globule size distribution. This is due to the complexity and nearly-perfect timing needed to control g-forces.  Some artisan cheese producers have opted to utilize gravity separation to isolate smaller fat globules, but this process can take many hours while imposing a food safety risk.  A new technology, ultrasonic separation, promises faster separation of fat globule fractions than gravity separation. This method utilizes sound waves that can rapidly separate the fat components of milk with a high specificity in globule sizes. In a recent Australian study, ultrasonic separation by dual transducers operating at 2 MHz achieved appreciable fractionation after 20 minutes and resulted in a 0.9 µm decrease in fat globule size. 

Keywords: ultrasonic separation, dairy processing, fat globule fractionation