ABSTRACT
Gums are long chain polysaccharides widely used in the food and many other industries as thickeners, stabilizers, and texture modifiers. Gums and related polysaccharides are produced in nature as storage materials, cell wall components, exudates, extracellular substances from plants or microorganisms, and in some cases from exoskeletons of shellfish such as lobsters, shrimps and crabs (e.g., chitosan). Some polysaccharides are simple in sugar composition, such as cellulose and β-D-glucans, which contain only one type of monosaccharide (e.g., β-D-glucose), while others are rather complex and may contain up to six types of monosaccharides plus one or two types of uronic acids. Common monosaccharides and uronic acids present in natural polysaccharides include D-glucose, D-galactose, D-mannose, D-xylose, L-arabinose, L-rhamnose, L-fucose, D-galacturonic acid, D-gulucuronic acid, D-mannuronic acid, and L-guluronic acid. The primary structure of a polysaccharide, i.e., monosaccharide composition, linkage patterns, and molecular weight, defines the solubility and conformation of the polymer chains in aqueous solutions, which in turn dictate the functional properties of the gums exhibited in food and other systems.
