Considerable interest has recently been generated on dietary fibers (DF), and soluble fibers have emerged both as a subject for research and therapeutic applications. The 'fiber hypothesis', put forward by Denis Bukitt and Hugh Trowel (1-4), suggests that consumption of unrefined carbohydrate food protects against many western ailments including colon cancer, diverticular disease, appendicitis, constipation, haemorrhoids, diabetes, heart disease, gall stones, and obesity among others. In the line of this hypothesis, many basic laboratory and clinical works have been done. The term 'dietary fiber' has been used to denote plant polysaccharides and lignin that are resistant to hydrolysis by human digestive enzymes (5,6). The detailed chemistry and metabolism of DF have also been studied (7-10). The classification of fiber is based on their chemical structures (11), and they can be divided into non-polysaccharides and non-starch polysaccharides. Lignin is the only non-polysaccharide fiber, which is a polymer of phenolic alcohol that is water insoluble. The non-starch polysaccharide can be divided into cellulose and non-cellulose fiber. Cellulose consists of un-branched D-glucose chains in 1,4-ß linkage and is water insoluble. Non-cellulose polysaccharides include hemicelluloses, mucillages, gums and pectins, and they consists of various ß linkages of wide variety of hexose and pentose sugars. The polysaccharide chains are heteroglycans (chains with more than one type of monosaccharide). The hemicellulosic materials are polymers of xylose, mannose and glucose with side chains of galactose and arabinose. The pectic substances are polymers of galacturonic acids. Likewise, the gums and mucillages are branched carbohydrate polymers (e.g. gum, which is a linear mannan with galactose side chains). Non-cellulose polysaccharides vary in degree of their water solubilities (7,9,10).