Ultrafiltration of Whole and Skim Milk

Abstract

Tubular and hollow fiber ultrafiltration membranes have been used to concentrate and fractionate both whole and skim milk. The effects of the process variables (pressure, temperature, feed flow rate, and feed composition) on permeate rate and membrane rejection coefficients were determined. The data indicate the significance of concentration polarization in the ultrafiltration of milk. For the tubular membrane system used in the ultrafiltration of whole milk, a four-parameter model provides a good description of the observed variation of permeate flux with process variables. In these studies, the rejection coefficients for milk proteins, fat, lactose, and ash did not vary significantly with temperature, pressure or fluid velocity. The implications of preconcentration of skim and whole milk prior to cheese manufacture are discussed.