Granulation behaviour of high lactose dairy superconcentrates

Granulation of whey permeate (WP) and demineralised whey (DW) superconcentrates was evaluated by addition of powder using a high-shear mixer during which consumption of electrical current was monitored. Granulation of DW required 50% more energy than that of WP and the resulting DW granules were larger (∼2×) indicating greater resistance to fragmentation. Furthermore, addition of whey protein isolate (WPI) into the back-mix powder resulted in more efficient granulation (reduced energy, finer granules etc.) of superconcentrated WP. This was linked to the higher water-holding capacity of WPI and a simple model based on protein content was proposed to predict occurrence of granulation. This study sheds light on granulation behaviour under these conditions. Interestingly, while high cohesiveness of superconcentrates, which is related to protein content, has been previously shown to negatively impact granulation, increasing the protein content of the granulating powder was shown here to have positive effects, which offers great potential for design of formulated products.