E400 - Alginic acid

Alginic acid, also called algin or alginate, is a polysaccharide distributed widely in the cell walls of brown algae, where through binding with water it forms a viscous gum. It is also a significant component of the biofilms produced by the bacterium Pseudomonas aeruginosa, the major pathogen in cystic fibrosis, that confer it a high resistance to antibiotics and killing by macrophages. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular or powdered forms.