MOLECULAR ARCHITECTURES AND FUNCTIONAL-PROPERTIES OF GELLAN GUM AND RELATED POLYSACCHARIDES

Certain linear and branched polysaccharides produced by unrelated spec ies of bacteria are grouped in the gellan gum family because of their conserved backbone structures. All have excellent rheological properti es and, thus, are useful in industrial applications. Physicochemical i nvestigations of these polysaccharides in solution and structural stud ies of them in the solid state using X-ray diffraction have provided m utually complementary results. The sturdy double-helix morphology that is characteristic of gellan gum prevails in other members of the gum family in spite of the presence of substituents and side chains. Assoc iation between double helices is facilitated by ions and water molecul es. The observed physical properties of solutions and gels made with m embers of the gellan gum family can be directly rationalized at the mo lecular level in terms of the interactions taking place between the po lymer helices.