Solution and gelling properties of gellan benzyl esters

Gellan benzyl esters of different degrees of esterification were prepared, and their gelation behavior was examined. Native gellan and gellan benzyl ester aqueous solutions and the ensuing aqueous gels obtained by cooling their solutions with added salt were studied by means of rheological and small-angle X-ray scattering experiments. Although esterification causes no fundamental changes in the gellan ordered structure, the introduction of bulky benzyl ester groups reduces the backbone propensity of double-helix formation and subsequent helix-helix association (gelation). In consequence, gellan-based gels become less stable both mechanically and thermally with esterification

Applications of biopolymers to processes of environmental control

Two new methods of insolubilizing in cellulose triacetate membranes, natural or synthetic polyelectrolytes, able to bind heavy metal ions, were experimented and discussed. The efficiency of the obtained membranes was tested by monitoring the cupric ion adsorption with a copper ion selective electrode (ISE

Solution Conformations of Gellan Polysaccharide

This symposium communication deals with the influence exerted by guanidinium hydrochloride, urea, and sucrose, resp., on the stability of the ordered chain conformation that can be assumed by gellan chains in dil. aq. soln. Guanidinium hydrochloride and sucrose stabilize the ordered chain state of gellan, though with different mechanisms, and eventually lead to gel formation. In contrast, urea acts ad a typical denaturing agent favoring the randomly coiled state of gellan. Much less pronounced appears the influence of the same cosolutes on the soln. properties of branched polysaccharides structurally related to gellan. Indexin