ABSTRACT
Alginates, or algin, is a generic term for the salts and derivatives of alginic acid. This acidic polysaccharide or gum occurs as the insoluble mixed calcium, sodium, potassium, and magnesium salt in the Phaeophyceae, brown seaweeds. Brown seaweed has been used as a food for centuries but the discovery of algin did not occur until about 1880. The process disclosed by Green consists of washing the brown seaweed with dilute acid to reduce the inorganic content of the weed. Flow properties of sodium alginate solutions and propylene glycol alginate solutions are concentration dependent. Alginate gels produced by interaction with calcium ions are dynamic systems; i.e., gel strength usually increases with time. Alginate molecules are in the fully hydrated state before formation of insoluble polymers. Insoluble polymers result from extensive interaction with calcium ions, beyond that required to achieve increased viscosity or gelation. Alginates possess good film forming properties which make them particularly useful in certain paper manufacturing applications.
