Sodium alginate: an overview

Sodium alginate (NaC6H7O6)n is an anionic straight chain polysaccharide. It is composed of repeating units of L-guluronic acid and D-mannuronic acid residues linked together via 1-4 glycosidic linkage. The source of sodium alginate is the seawater brown algae and is present in the outermost covering, the cell wall of the algae. Sodium alginate can be obtained from different species of algae and each species has a different concentration of it. Sodium alginate has different properties, such as pH-sensitivity, nontoxicity, biodegradability, perishability, safety, nonimmunogenicity, linearity, hydrophilicity, poly-anionicity, cost-effective adhesion, and biocompatibility. Sodium alginate also shows chelating mucoadhesion, ease of gelation, thickening ability, film making ability, low-cost transparency, a gelling negotiator, stabilizing nature, and high viscosity in water. This chapter also discusses various applications of sodium alginate in the food industry, wound dressings, tissue engineering, wastewater and industrial effluent treatment, tissue engineering, gene delivery, and drug delivery.