Separation of aggregated β-lactoglobulin with optimised yield in a decanter centrifuge

The interest in individual whey protein fractions, especially the main proteins α-lactalbumin and β-lactoglobulin, has been growing due to their unique nutritional value and their exceptional technofunctional properties. Various fractionation and purification methods have been published. However, none of them achieved highest purity, maximal recovery, and transferability to industrial scale. This study used thermal treatment for selective aggregation of β-lactoglobulin, which was subsequently separated in a pilot-scale decanter centrifuge from the α-lactalbumin-enriched centrate. The aim was to investigate if the centrifugal separation can be improved by pH-induced flocculation of the aggregates compared with non-flocculated suspensions at pH 7.0. With various analytical methods, it was demonstrated that the strongest flocculation occurred at pH 4.4 and facilitated separation of aggregate fragments sized below 20 μm. Finally, separation efficiencies of more than 99% were achieved by aggregate flocculation in the pilot-scale decanter even at low centrifugal forces.