EFFECT OF CONCENTRATION AND TEMPERATURE ON THE DENSITY AND VISCOSITY OF SKIM MILK RETENTATES

Density and viscosity were determined for skim milk and skim milk retentates using a pycnometer and Haake viscometer, respectively. Determinations were made at 20, 30, 40, and 50-degrees-C and over a protein range of 3.00% to 19.21%. A regression model was developed to describe the effect of temperature and protein level on the density of the retentate. The power law equation was used to determine flow behavior indices (n) and consistency indices (K) for the samples. The n values decreased and K values increased with increased protein concentration of retentates. Protein, temperature, and their interaction affected the n and K values.