Continuous Flow Ultrasonic Skimming of Whole Milk in a Liter-Scale Vessel

Ultrasonic separation is a promising chemical processing technology suitable for a range of separation applications. Previously, the ultrasonic separation and fractionation of milk fat from natural whole milk had only been demonstrated in batches of up to 3 L. This study demonstrated the continuous ultrasonic separation of milk fat using a 1.8 L flow reactor at volumetric flow rates scaled up to 33 L/h by using simultaneous 1 MHz/2 MHz sonication near 30 degrees C. Single pass separation was compared with fat separation cycles consisting of passing the obtained partially skimmed or fat enriched milk multiple times through the reactor for further fat skimming or concentration, respectively. This work demonstrated continuous milk fat globule size fractionation into fat enriched and skimmed streams assisted by ultrasound with collected product volumes significantly larger (between 0.2 and 5 L) than previously achievable in batch processing (between 0.02 and 0.2 L).