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The Influence of Milk Protein Content on the Surface Tension and Viscosity

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Acta Veterinaria Scandinavica200344 (Suppl 1) :P86

  • Published:


  • Surface Tension
  • Protein Content
  • Lactose
  • Dynamic Viscosity
  • Milk Sample

From the organic milk components the proteins influence mostly the surface tension (σ) and the dynamic viscosity (h). The physical properties of milk are influenced by the dispersion degree of the components. Casein (diameter 0.1–0.005 μ) and albumin (diameter 0.015–0.005 μ) form colloid dispersions. Lactose (diameter 0.00067 μ) is molecular dispersed. Therefore is the viscosity and surface tension influenced by protein and not by lactose.

Milk samples from 16 dairy cows, with ages between 3–10 years, in different physiological states were analysed. The experiment was repeated at an interval of two weeks, four times.

For the measuring of s the dynamic stalagmometric method was used (stalagmometer Traube). The dynamic viscosity was determined with the Ostwald viscometer [1]. A positive correlation between the protein content and the two biophysical parameters was observed.

The highest viscosity is 2,2639 cP (230% higher than h of water. Casein reduces s to 75% from the value for water σ.

We concluded that the viscosity is a biophysical parameter that can be used in appreciation the protein content of milk. Milk with high protein content (>3 g%) has a h round 2 cP. Milk with low protein content (<3 g%) has a η round 1.5 cP and below.
Figure 1
Figure 1

The positive correlation between protein (g%) and η (cP).

Figure 2
Figure 2

The negative correlation between protein (g%)and σ (10-1 dyn/cm.

Authors’ Affiliations

University of Agricultural Sciences Timisoara, Calea Aradului, 119, RO-1900 Timisoara, ROMANIA


  1. Caprita Rodica, Cretescu Iuliana: Methods in biophysics. Edited by: Mirton, Timisoara. 2000Google Scholar


© The Author(s); licensee BioMed Central Ltd. 2003

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.