Explain Viscosity of proteins

Viscosity reflects resistance to flow. The  main  single factor influencing the viscosity  behavior  of protein  fluids  is   the  apparent  diameter  of  the  dispersed molecule, which is dependent on the following parameters :

a.   Intrinsic character of protein molecule (molar mass, size, volume, structure and asymmetry, electric charges and ease of deformation), environmental factors such as pH, ionic strength and   temperature, can  modify  these  characteristics    
through  unfolding;

b. Protein  solvent interaction  which  influence swelling, solubility and hydrodynamic sphere surrounding the molecule, and

c. Protein-protein   interactions which determine the aggregates. Protein ingredients are generally used at a high concentration at which protein-protein interactions predominate.