The thickening properties of native gellan gum are due to freeze drying–induced aggregation

The gelation of native gellan gum was investigated. Native gellan was found to dissolve in water at 90 °C as a polydisperse mixture of aggregates with an average aggregate number of ≈10. Extensive heating (>10 h) at 90 °C broke down the aggregates into individual chains. Solutions of these aggregates formed permanent gels without added salt. In contrast, solutions of individual chains formed weak gels under the same conditions. The results indicate the role that soluble aggregates, probably formed on drying, have in imparting gelling and stabilizing capacities to food preparations of native gellan gum. [Display omitted] •Native gellan forms oligomers in solution following freeze drying.•Native gellan is solubilized as monomers following extensive (>10h) heating at 90°C.•1% oligomeric native gellan solutions form self-supporting gels at room temperature.