(NaC6H7O6) is the sodium salt of alginic acid. Sodium alginate is a gum. Potassium alginate (KC6H7O6) is the potassium salt of alginic acid. Calcium alginate (CaC12H14O12), is made from sodium alginate from which the sodium ion has been removed and replaced with calcium (ion exchange). Production The manufacturing process used to extract sodium alginates from brown seaweed fall into two categories: 1) calcium alginate method and, 2) alginic acid method. Chemically the process is simple, but difficulties arise from the physical separations required between the slimy residues from viscous solutions and the separation of gelatinous precipitates that hold large amounts of liquid within their structure, so they resist filtration and centrifugation. Uses Alginate absorbs water quickly, which makes it useful as an additive in dehydrated products such as slimming aids, and in the manufacture of paper and textiles. It is also used for waterproofing and fireproofing fabrics, in the food industry as a thickening agent for drinks, ice cream, cosmetics, and as a gelling agent for jellies, known by the code E401. Sodium alginate is mixed with soybean flour to make meat analogue. Alginate is used as an ingredient in various pharmaceutical preparations, such as Gaviscon, in which it combines with bicarbonate to inhibit gastroesophageal reflux. Sodium alginate is used as an impression-making material in dentistry, prosthetics, lifecasting, and for creating positives for small-scale casting. Sodium alginate is used in reactive dye printing and as a thickener for reactive dyes in textile screen-printing. Alginates do not react with these dyes and wash out easily, unlike starch-based thickeners. It also serves as a material for micro-encapsulation. Calcium alginate is used in different types of medical products, including skin wound dressings to promote healing, and may be removed with less pain than conventional dressings. Alginate hydrogels Alginate may be used in a hydrogel consisting of microparticles or bulk gels combined with nerve growth factor in bioengineering research to stimulate brain tissue for possible regeneration. In research on bone reconstruction, alginate composites have favorable properties encouraging regeneration, such as improved porosity, cell proliferation, and mechanical strength, among other characteristics. Alginate hydrogel is a common biomaterial for bio-fabrication of scaffolds and tissue regeneration. See also Hyaluronic acid: a polysaccharide in animals. Agar References External links Alginate seaweed sources Alginate properties Polysaccharides Natural gums Edible thickening agents Copolymers Dental materials Excipients Algal food ingredients Brown algae Food stabilizers E-number additives