IV) Other polysaccharides

Other polysaccharides

    • Many other polysaccharides are present in varying amounts in various plant foods. These include i) cellulose ii) fructosans iii) galactans iv) pentosans v) pectins and vi) Hemicellulose.
    • All these are not acted upon by the digestive juices in the human intestinal tract. They help to increase faecal bulk and prevent constipation.
    • Cellulose is a polysaccharide made up of glucose.
    • Its chemical structure differs from starch in the mode of linkage of glucose molecules.
    • Fructosans are polysaccharides formed by the combination of large no of fructose molecules.
    • Fructosans are present in onions and Jerusalem artichoke.
    • Galactans are polysaccharides composed of galactose molecules.
    • They occur in large amounts in sea weeds.
    • The well known polygalactan is agar-agar.
    • Pentosans are polysaccharides formed by the combination of a large number of pentoses.
    • They occur in grass and straw.
    • Pectins are formed by the combination of large number of galacturonic acid molecules.
    • In the presence of sucrose and citric acid, pectin forms a gel.
    • Hemicelluloses are polysaccharides containing pentoses, hexoses and uronic acids.
    • They are present in all vegetables, bran of cereals and hull of legumes.

Last modified: Saturday, 28 April 2012, 7:26 AM