CASE-STUDIES OF PHYSICAL AND CHEMICAL GELS BASED ON MICROBIAL POLYSACCHARIDES

Microbial anionic polysaccharides, although structurally closely relat ed, exhibit strikingly different gelling properties in aqueous media ( physical gels formation). Experimental observations are traced to diff erences, minor differences in some instances, in primary structures. C hemical gels have been prepared using deacylated gellan by means of an interchain partial esterification procedure, and a sample subjected t o preliminary characterization in terms of swelling properties. NMR wa ter proton relaxation data show that such amples display a remarkable water retention capability.