Alginát

Alginate, or alginát in Hungarian, is a naturally occurring polysaccharide obtained mainly from brown seaweeds (Phaeophyceae). It consists of two uronic acid residues, β-D-mannuronic acid (M) and α-L-guluronic acid (G), arranged in blocks. The ratio and arrangement of M and G units determine its viscosity and gelling behavior. Industrially, alginate is extracted as alginic acid and converted into salts such as sodium alginate, which are widely used in food, pharmaceuticals, and industry.

Gelling and thickening properties arise when alginate solutions come into contact with multivalent cations, most commonly calcium (Ca2+). The calcium ions crosslink G-blocks in the polymer, forming a three-dimensional network often described by the egg-box model. Gel strength and porosity depend on the M/G ratio, molecular weight, and concentration. Alginate is soluble and stable at neutral pH and is typically non-toxic and biocompatible.

Common uses include as a thickener and stabilizer in foods such as dairy products, sauces, and jams, and in molecular gastronomy for spherification. In medicine and dentistry, alginates are used in wound dressings and as impression materials. They also serve as pharmaceutical excipients for controlled release and viscosity modification. Environmental and supply considerations center on sustainable harvest of brown seaweeds and purity standards to avoid contaminants.

Safety and regulation: Alginate is generally regarded as safe for many food and medical applications, with regulatory approval in numerous countries. Purity specifications and testing for impurities, including heavy metals, are standard parts of commercial alginate products.