New Developments in Water-Soluble Polysaccharides

Abstract

Natural water-soluble polysaccharides usually occur as food reserves, as components of plant fluids, as exudate gums or, infrequently, as components of hemicelluloses (1,2). A great many naturally occurring polysaccharides are dispersible in water and some dispersions produce gels, either directly or indirectly. Often these gels fulfill a significant function in their biological source. For example, polysaccharide gels are important in ocular fluids, in synovial fluids, in protecting microorganisms or injured plant surfaces from desiccation and, as mucilaginous gels, in acting as emollients on membrane surfaces of animals. A lesser number, but the bulk of polysaccharides, are water insoluble and are not dispersible. The principal one of these is cellulose, but the most abundant group are the plant hemicelluloses. The water-soluble and water-dispersible polysaccharides are used in various food and nonfood products. Because of the growing industrial need for water-soluble and water-dispersible polysaccharides, their number and variety are increased by chemically modifying natural polysaccharides that are less soluble or even insoluble; or, water-soluble polysaccharides are created through the biosynthetic use of microorganisms or enzymes. A new group of water-soluble molecules which may find application in the future are manmade glycoproteins.