Salt-induced thermal gelation of xyloglucan in aqueous media.

The influence of NaSO as a kosmotropic salt on the thermogelation of xyloglucan (XG) solutions was measured by rheology. The gelation occurred at lower temperatures and shorter times when the salt concentration was increased above 0.5 mol.L. For NaSO concentrations equal to 1 mol.L, a not thermoreversible elastic hydrogel was obtained. Salts containing various types of anions were used, and it was observed that SO, HPO and HPO promoted the formation of a gelled network. The gel structure was observed using confocal laser scanning microscopy and scanning electron microscopy. In XG containing SO at 1 mol.Laggregates and gels were formed by interconnected sub-micrometer XG particles. Increasing the concentration of SO led to conformation changes in the XG, from a twisted/helical to an extended/flat conformation, as observed using circular dichroism. The naturally occurring hydrophobic sequences promoted an economically feasible XG gelling that may produce thermo and kosmo-sensitive hydrogels.