Sodium alginate is a neutral salt in which the carboxyl groups of alginate are bonded with a sodium ion. Alginic acid is not soluble in water but sodium alginate is soluble in both cold and hot water to produce a smooth viscous solution.
When calcium ions are added to a sodium alginate solution, calcium ions react instantly with alginate to form a gel.
The time taken to form a gel can be controlled by controlling the calcium ions.
These unique properties result in sodium alginate being used as a thickener, gelling agent and stabilizer in a wide range of industries.