Gellan gum

What is the similarity between Kelcogel, Gelrite, Phytagel and Gel-Gro? All of these are the trade names of the same substance: Gellan gum!

Gellan gum is a microbial exopolysaccharide produced by the bacterium Pseudomonas elodea. Industrial production of gellan gum is carried out using Sphingomonas paucimobilis. Gellan is a high molecular weight polysaccharide composed of repeating units of beta d glucose (60%), L-rhamnose (20%), and glucuronic acid(20%)

There exist three types of gellan gums: Native, deacetylated and clarified. Native gellan gum has two acyl groups in its backbone which are removed by alkaline treatment in deacytylated gellan gum.  Hot deacytylated gellan gum when filtered to remove the protein components yields clarified gellan gum. This is widely used to make agar substitute.

Gellan gum is widely used in the food industry. It is basically used as a substitute for gelatin.  Use of gellan gums in starch jellies helps reduce the setting time of jellies by almost half while maintaining the texture and structure of the end product. It helps prevent moisture fluctuations in sugary foods, icings and toppings. It can also effectively act as a bulking agent for icecreams. Gellan gum when added during cheese making was found to enhance water retention and reduce the losses of protein. Gellan gum also has a probable use in fried foods wherein due to its hydrophilic character, it may reduce the oil-uptake by the food being fried.

The potential of gellan gum in controlled drug release has also been widely studied. Phytagel™ and Gelrite™ are being used as bacterial growth media and medium for plant tissue culture in place of agar. Gellan gum also has potential to replace agarose as the electrophoresis substrate provided it is used in conjunction with a second polymer such as hydroxymethylcellulose to reduce electroosmosis. 

Reference:

Bajaj et al, Gellan Gum: Fermentative production, downstream processing and applications, Food Technol. Biotechnol, 45(4), 341-354, (2007)