Colloidal stabilisation of β-casein enriched whey protein concentrate

The aim of this study was to produce a colloidally stable whey protein concentrate enriched in β-casein. Microfiltration (MF) of skim milk was completed at ∼7 °C (pore size 0.1 μm) followed by ultrafiltration of the MF permeate at ∼9 °C to concentrate the β-casein-whey protein fraction (BWPC). The casein:whey protein ratio of the BWPC system was ∼25:75. Skim milk was then added to ultrafiltration retentate at a level supplying 0, 0.1, 0.3 and 0.5% (w/w) of the total protein, followed by evaporation and spray drying. During evaporation of the BWPC stream without skim milk addition, there was significant precipitation of β-casein, resulting in an increase in particle size due to uncontrolled aggregation. Addition of low amounts of skim milk was effective at reducing the precipitation of β-casein during evaporation at 50 °C, indicating that the addition of micellar casein to the BWPC stream was able to prevent uncontrolled β-casein aggregation.