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

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