Xanthan Gum

Xanthan gum is produced by fermenting corn sugar. Xanthan Gum is made by the fermentation of corn sugar with a microbe called Xanthomonas campestris, from which the name is derived. It is most commonly used as a stabilizer, emulsifier and thickener in dairy foods such as yogurt and sour cream and salad dressings. It is a thickenier and emulsifier used to thicken and stabilize salad dressings, sour cream, etc.

Xanthan gum is a long chain polysacharide composed of the sugars glucose, mannose, and glucuronic acid. The backbone is similar to cellulose, with added sidechains of trisacharides (three sugars in a chain). It is a slimy gel produced by the bacterium Xanthomonas campestris, which causes black rot on cruciferous vegetables such as cauliflower and broccoli. The slime protects the bacterium from attach by viruses, and prevents it from drying out.

The backbone of Xanthan gum is similar to cellulose, but the trisacharide side chains of mannose and glucuronic acid make the molecule rigid, and allow it to form a right-handed helix. These features make it interact with itself and with other long chain molecules to form thick mixtures and gels in water.

Xanthan is a kind of biopolymer made from corn starch through biological process,by a strain named Xanthomonas Campestris. Xanthan is a kind of bio-polysaccharide composed of glucose, mannose,glucuronic acid, acetic acid and pyruvic acid.

A complete xanthan molecule has a linear cellulose-like backbone with many side chains.Because of acidic groups present in the side chains, xanthan displays poly-anionics in water solution.In water the electrically-charged side chains wind on the cellulose main chain, to form a rod-like rigid structure.This is the primary structure of xanthan molecule.Through hydrogen bond the biopolymer molecules exist as a dual-helix, which is regarded as the secondary structure. Through non-covalent bond many dual-helixs arrange in good order to form helix aggregates. This is the tertiary stereo structure of xanthan molecule. The molecular structure of xanthan gives it unique features over other polymers:

- high viscosity yield at low concentration
- good thixotropy and pseudo-plasticity
- tolerant to acid, alkaline and salt; tolerant to oxidant and enzymatic degradation
- toerant to elevated temperature; keep stable through several freeze/melt cycles
- good compatibility with acid, alkaline, salt, reducing agent, surfactant, biocide, natural or synthetic thickener when in the same system
- good dispersing ability, emulsifying ability,and solids/oil-drops suspending ability The unique features of xanthan render it wide application in many industries.