Gum tragacanth gel: formationand applications

Gum tragacanth (GT) does not readily form a true gel using conventional methodsowing to its specificstructure and thus chemical cross-linkers e.g. glutaraldehydehave often to be used.The residue of these chemicals and their derivatives have to be removed/extracted from the final gel not only due to their toxicity but also because of the possible interactions they may have with the bioactive compounds carried and/or delivered by the network. These drawbacks limit their application if food industry and tissue engineering. This review article deals with the structural characteristics and physicochemical properties of GT as one of the most widely used polysaccharide in food and pharmaceutical industry and discusses the various methods commonly employed for gelation including physical and chemical approaches. Moreover, a novel green approach which is based on the authors' recent studies as well as other safe and cross-linker free techniques such as irradiation that can be used for making GT gel will be introduced.