Gellan

Form gels, with strenghts depending on type and concentration of cation present, and on the degree of acetylation [1]. Unmodified gellan forms soft and spongy gels while the deacetylated gellan forms hard and brittle gels [4]. At ethylation and propylation >0.17 per gellan unit, gellan is unable to attain a gellan-like ordered state [2]. In the presence of gel-forming cations, firm brittle gels are formed through cation-mediated helix-helix aggregation which show marked thermal hysteresis. The physical properties depend on the type and concentration of the cations. Divalent ions like Ca²⁺ and Mg²⁺ give stronger and more stable gels than monovalent ions like Na⁺ and K⁺ [5]. High levels of co-solute like syrup can reduce the level of cations needed for gelling [5].