What is alginate?
“Alginate”, also known as alginate, is the term usually used for the salts of alginic acid. However, this word also usually refers to all the derivatives of alginc acid and alginic acid itself. Alginate is a kind of natural polysaccharide existing in the cell walls of brown seaweed as the calcium, magnesium and sodium salts of alginic acid. Alginic acid is a mix-polysaccharide composed of D-mannuronic acid (M) and L-guluronic acid (G), showed as following. The calcium salt of alginate does not dissolve in water while the sodium salt does. Because of that, the basic method behind the extraction of alginate from the seaweed is to concert all the alginate salts to the sodium salt, dissolve this in water and remove the seaweed residue by filtration.
Chemical Structure of M Acid and G Acid