Gellan Gum and Its Applications – A Review

For decades microbial exopolysaccharides have been invaluable ingredients in the food industry, as well as having many attractive pharmaceutical and chemical applications. The biopolymer gellan is a more recent addition to the family of microbial polysaccharides that is gaining much importance due to its novel property of forming thermo-reversible gels when heated and cooled. It has applications in diverse fields in the food, pharmaceutical and many other industries.1Gellan gum is an anionic, high molecular weight, deacetylated exocellular polysaccharide gum produced as a fermentation product by a pure culture of Pseudomonas elodea2, with a tetrasaccharide repeating unit of one α-L-rhamnose, one β- D-glucuronic acid and two β-D-glucose residues3,4. The production organism is an aerobic, gram-negative bacterium, which has been very well characterized and demonstrated to be non-pathogenic5. This organism was found during an extensive screening programme seeking naturally occurring hydrocolloids with useful properties.