Sodium alginate (E401) - an organic chemical compound, sodium alginic acid. It is obtained from seaweed (brown algae) thrown to the shores of the Atlantic. It is colorless and tasteless. Sodium alginate is used as a thickening agent, gelling agent or stabilizer, it swells easily and binds water well. It inhibits the absorption of strontium. It has gelling properties, after adding cold water, it gets off like gelatin. Sodium alginate in conjunction with calcium chloride is used for spherulizing.
Sodium alginate is a natural decoction of seaweed, which at lower temperatures has gelling properties, so adding it to cold water will make it similar to gelatin. Alginate reacts with calcium chloride, which makes the gel structure more strong and hard.