Gelan

Gelan is a type of exopolysaccharide produced by the bacterium Sphingomonas elodea. It is a high molecular weight polysaccharide composed of repeating units of glucose, glucuronic acid, and rhamnose. Gelan is known for its excellent gelling properties, forming strong, heat-stable gels at very low concentrations. It is also resistant to acid and salt, making it a versatile ingredient in various applications.

The structure of gelan consists of repeating tetrasaccharide units. These units are arranged in a specific sequence, leading to the formation of a helical structure. When ions, particularly divalent cations like calcium, are present, they can interact with the negatively charged carboxyl groups on the glucuronic acid residues. This interaction causes the helices to aggregate, forming a three-dimensional network that traps water and results in gel formation.

Gelan finds widespread use as a gelling agent, stabilizer, and thickener in the food industry. It is employed in dairy products, desserts, sauces, and jams to improve texture and stability. In the pharmaceutical sector, gelan is used in drug delivery systems and as a component in culture media for microorganisms. Its ability to form clear, brittle gels also makes it suitable for cosmetic formulations, such as creams and lotions. The production of gelan typically involves microbial fermentation, followed by purification processes to isolate the polysaccharide. Its biocompatibility and biodegradability are key advantages for its various applications.