Optimizing the use of power ultrasound to decrease turbidity in whey protein suspensions

This research employed power ultrasound (US) to decrease the turbidity of whey suspensions. US was applied using a 20 kHz generator and different power levels (3 and 15 W) for different application times (5 and 15 min) at different temperatures (20, 60 °C, and no temperature control [NTC]) to whey suspensions obtained at 4 different steps in a commercial process. The whey suspensions varied from 6.9 to 30.2% solids and 13.5 to 88% protein. This research shows an approximately 90% decrease in turbidity when US was applied to a whey suspension of 28.2% of solids containing 35.6% of protein on a dry basis. The greatest decrease in turbidity was observed when US was applied for 15 min using 15 W of electrical power at 60 °C and NTC conditions. Surprisingly, when US was used in whey suspensions containing 88.0% protein an increase in turbidity of samples was observed.