Salts of alginic acid found in many seaweeds as calcium salts or the free acid. Chemically, alginic acid is a non-starch polysaccharide of mannuronic acid. Iron, magnesium and ammonium salts of alginic acid form viscous solutions and hold large amounts of water.
Used as thickeners, stabilisers and gelling, binding and emulsifying agents in food manufacture, especially ice cream and synthetic cream. Trade name Manucol.
Used in combination with magnesium and aluminium hydroxides in antacids; alginate-containing antacids form a ‘raft’ floating on the gastric contents, so reducing oesophageal reflux.