Ultrafiltration and Diafiltration's Effect on Casein Micelles

PASTEURIZED skim milk was ultrafiltered to a 6X volume concentration ratio (VCR) using hollow-fiber membranes with a mol wt cutoff of 50,000 daltons. The milk was then diluted to IX with distilled water and diafiltered to a 6X VCR. This removed 99% of the lactose, 36% of the calcium and 42% of the phosphorus. No changes were observed in the size distribution of casein micelles, the equilibrium between micellar and serum casein, the calcium or phosphorus content of micellar casein, or the hydration of the casein as a result of ultrafiltration or diafiltration.