Alginic acid

Alginic acid, also called algin or alginate, is an anionic polysaccharide distributed widely in the cell walls of brown algae, where through binding with water it forms a viscous gum. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular or powdered forms.

Structure

Alginic acid is a linear copolymer with homopolymeric blocks of (1-4)-linked β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) residues, respectively, covalently linked together in different sequences or blocks. The monomers can appear in homopolymeric blocks of consecutive G-residues (G-blocks), consecutive M-residues (M-blocks) or alternating M and G-residues (MG-blocks).

Forms

Alginates are refined from brown seaweeds. A wide variety of brown seaweeds of the phylum Phaeophyceae are harvested throughout the world to be converted into the raw material commonly known as sodium alginate. Sodium alginate has a wide use across a wide variety of industries including food, textile printing and pharmaceutical. Dental impression material utilizes alginate as its means of gelling. Alginate is both food and skin safe.