Examination of the impact of using lactose or permeate for protein standardisation of skimmed milk on viscosity characteristics during evaporation

The effect of permeate and lactose for protein standardisation of skim milk concentrate, was investigated during evaporation. Analysis of the viscosity–total solids (TS) profiles of each treatment demonstrated that the unstandardised protein sample had the greatest increase in viscosity, followed by permeate and finally lactose-standardised samples. Heat stability and acid buffering capacity of the permeate standardised skim milk samples were higher when compared to the lactose-standardised samples. This work identifies how standardisation media can impact the viscosity of concentrated skim milk, enabling higher TS at the evaporator outlet in some circumstances which could have the potential to improve overall process efficiency. Furthermore this work demonstrates that, evaporating to a target viscosity rather than target TS would offer greater control and consistency during processing.