5. Functional properties

5.1 Solubility

All carrageenans are soluble in water and hot milk (75°C). Solubility is limited by the solution's viscosity.

Carrageenan kappa and iota in the form of sodium salts are soluble in cold water, while salts of other cations such as potassium and calcium do not dissolve completely, exhibiting only partial hydration. Lambda carrageenan is totally soluble in cold water, irrespective of the cations present in the medium.

In cold milk, lambda carrageenan is the most dispersive and viscous, with no need for solubilizing salts. Its insensitivity to calcium and potassium ions, and the large number of sulfate groups may explain this behavior.

Although practically insoluble in cold milk, kappa and iota carrageenans...