Gellan gum

Gellan gum is an extracellular polysaccharide secreted by the microorganism Sphingomonas elodea (ATCC 31461) previously referred to as Pseudomonas elodea. Commercially it is manufactured by a fermentation process. It is available in two forms, high acyl (HA) and low acyl (LA). Gellan gum forms gels at low concentrations when hot solutions are cooled in the presence of gel-promoting cations. An overview of the manufacturing process and chemical structure of gellan gum is given. The functional differences between the two forms of gellan gum are reviewed in detail with regard to hydration, gelation, stability, and texture. Methods for the effective preparation of gellan gum solutions and gels are described for the HA and LA forms. The effects of food ingredients such as salts, sugars, and acids on gel properties are discussed in relation to the main applications. Finally, the main applications of gellan gum in food are described with example formulations.