Rheological Properties Of CMC Aqueous Solutions And Its Application In The Stabilization On Acidified Milk Drinks

Carboxymethylcellulose, CMC, in aqueous solutions are used in many applications that exploit its rheological properties. If new applications are to be found and existing ones improved, it is necessary to determine the viscoelastic and rheological material functions of the solution system so that they can be employed during processing and in the subsequent use of a product. CMC can be used in acidified milk drinks as stabilizer. It will be useful for this application to study the interaction between CMC and casein micelles at low pH.CMC aqueous solution exhibits pseudoplastic behaviour. Zero-shear viscosity increases with the molar mass and degree of substitution (DS). While increasing the concentration of CMC, the viscosity increases, and it can form gel when the concentration is high enough. The viscosity of CMC solution decreases with the pH. When lower than pKa, the viscosity rises again. The CMC solutions have polyelectrolyte effect. By adding monovalent (Na⁺, K⁺), this polyelectrolyte effect can be increasingly compensated for. Bivalent low-molar-mass electrolytes (Mg²⁺, Ca²⁺) also hinder the volume expension of a polyelectrolyte coil. An increase in the salt concentration first causes a fall in the viscosity. If the salt concentration is further increased, the viscosity rises again. A explanation offered for the viscosity increase is the formation of superstructures via bridging bivalent ions. In high concentrations, large bivalent cation (Ca²⁺) leads to flocculation for CMC with higher DS. By adding sucrose, the viscosity of CMC solution increases.