FLOW PROPERTIES OF FREEZE-CONCENTRATED SKIM MILK

The flow properties of freeze-concentrated skim milk, determined with a concentric cylinder viscometer; were well described by the simple po wer-law rheological model over the temperature range from -3.4 to +20 degrees C. High-total-solids freeze-concentrated skim milk (35-40% tot al solids) exhibited non-Newtonian behaviour while lower concentration s gave Newtonian flow properties. The magnitude of the flow behaviour inner was between 0.8 and 1.0. The Arrhenius model described well the effect of temperature on apparent viscosity in this temperature range. Statistical analysis showed that there was no difference in viscosity between condensed thermally evaporated skim milk and freeze-concentra ted skim milk. However the viscosities of reconstituted skim milks wer e different: the reconstituted product made from evaporated milk had a slightly higher viscosity than that of freeze-concentrated milk. (C) 1997 Elsevier Science Limited.