Portal de Periódicos da CAPES

The Viscosity of Natural and Remade Milk

1924; Elsevier BV; Volume: 7; Issue: 2 Linguagem: Inglês

10.3168/jds.s0022-0302(24)94009-4

1529-9066

O. L. Evenson, L W Ferris,

Granular flow and fluidized beds

Summary The relation of viscosity to the total solids is shown by means of the expression V − 1 T . S . in which V = Time of flow of milk × specific gravity of milk Time of flow of water × specific gravity of water and T.S. = total solids expressed as parts by weight of milk solids per gram of fluid milk. For a given number of samples the values for V − 1 T . S . for natural pasteurized milk varied from 5.68 to 7.18 and for remade milk from 6.26 to 12.60 at 25°C. The figures for mixtures containing 15 to 30 per cent of remade milk varied from 5.96 to 8.37. When the viscosity was determined at 15°C. the figures varied from 7.20 to 7.67 for natural pasteurized milk, from 6.70 to 8.06 for market milk and from 7.13 to 16.63 for remade milk. The viscosity of milk as determined is, to a certain extent, dependent upon the temperature at which the milk has been held. The viscosity is decreased slightly by pasteurization at 62−65°C. for 30 minutes, but considerably increased by heating at 75−80°C. for the same length of time. Homogenization at a high pressure has considerable effect on the viscosity, while the emulsor has little or no effect. By means of a high speed centrifuge it was found possible to throw out milk solids from both natural and remade milk to such an extent as to lower the values for V − 1 T . S . as compared with the values for the original milk. The sediment obtained from remade milk differed in quantity and character from that of natural milk.