Alginic acid

Alginic acid (also known as alginate) is a natural polysaccharide that is extracted from the cell walls of brown algae. It is widely used in the food industry, pharmaceuticals, and various industrial applications due to its unique properties such as gel-forming, thickening, and stabilizing.

History

The discovery of alginic acid dates back to the 1880s when it was first isolated by the British chemist E.C.C. Stanford. The commercial production of alginates began in the early 20th century, primarily in the United States and the United Kingdom.

Structure and Properties

Alginic acid is a linear copolymer with homopolymeric blocks of (1-4)-linked β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) residues, covalently linked in different sequences or blocks. The monomers can appear in homopolymeric blocks of consecutive G-residues (G-blocks), consecutive M-residues (M-blocks), alternating M and G-residues (MG-blocks).

The properties of alginic acid, such as its ability to form gels and its viscosity, are largely determined by the ratio and sequence of the M and G blocks. The G-blocks form strong gels, while the M-blocks are responsible for the viscosity of the alginate solutions.

Uses

Alginic acid has a wide range of applications due to its unique properties. In the food industry, it is used as a thickening agent, stabilizer, and to improve the texture of foods. In pharmaceuticals, it is used in the production of controlled-release drugs and as a disintegrant in tablets. In industry, it is used in the production of paper, textiles, and in water treatment processes.

Health Effects

Alginic acid is generally considered safe for consumption. However, excessive consumption can lead to gastrointestinal issues such as bloating and diarrhea. It can also interfere with the absorption of certain nutrients and medications.

See Also

• Brown algae
• Polysaccharide
• Food industry
• Pharmaceutical industry