Sodium alginate (C6H7O6Na)n, also called Algin, is primarily composed of the sodium salt of alginic acid, which is a polysaccharide consisting of a-L-mannuronic acid (M unit) and b-D-glucuronic acid (G unit) linked by 1,4-sugar glycosidic bonds and composed of different proportions of GM, MM, and GG fragments. It's usually used in food industry as stabilizer, emulsifier and thickener.