ABSTRACT
Polysaccharides having multiple monomer units are called heteropolysaccharides. Some polysaccharides may also have branches, as in the case of amylopectin. As a result of the availability of a large variety of monosaccharides and of different types of linkages, polysaccharides found in nature are innumerable. Since the linkage between monosaccharides is actually a full acetal, polysaccharides necessarily involve the closed ring form of sugars, usually in the pyranoside form. Mannans are widely distributed in plant and microbial worlds both as homo- and hetero-polysaccharides. The nature of the molecule depends upon the source from which it is obtained. Similarities in the solid state structures of glucans and mannans support the belief that polysaccharide chain conformation is governed mostly by its type of linkage rather than the residue. The freely rotating polysaccharide is a hypothetical model that results when the rotation of the sugar residues about the interunit glycosidic bonds adjoining the bridge oxygen atom is completely free.
