Algin

Algin is a colloquial term sometimes used to refer to alginic acid or its salts, particularly sodium alginate. Alginic acid is a polysaccharide found in the cell walls of brown algae, a type of seaweed. It is a linear polymer composed of mannuronic acid and guluronic acid residues. Alginic acid itself is insoluble in water, but when reacted with alkaline substances, it forms alginates, which are soluble salts.

The most common alginate is sodium alginate, which is widely used in the food industry as a thickener, stabilizer, and gelling agent. It is a key ingredient in products such as ice cream, yogurt, salad dressings, and jams, helping to create desired textures and prevent separation. Sodium alginate is also utilized in pharmaceuticals as a binder in tablets and as a component in antacids to form a raft that floats on stomach acid. In other applications, alginates are used in textile printing, papermaking, and as a material for wound dressings due to their absorbent properties and ability to form a protective gel. The extraction and processing of alginates typically involve treating the brown algae with alkaline solutions to dissolve the alginic acid, followed by precipitation and purification of the desired salt.