Cereal Chem 59:430 - 435. | VIEW
Carbohydrates of Field Bean (Dolichos lablab).
P. V. Salimath and R. N. Tharanathan. Copyright 1982 by the American Association of Cereal Chemists, Inc.
Field bean endosperm sugars soluble in 70% ethanol were d-glucose, D-galactose, D-fructose, sucrose, raffinose, stachyose, and verbascose. The endosperm was composed principally of starch, whereas the hulls were rich in dietary fiber components. In vitro digestion of the native starch granule by glucoamylase and salivary alpha-amylase revealed characteristic enzyme degradation patterns in scanning electron microscopy. Glucoamylase digestion of a granule resulted in typical onion-type layering, unlike alpha- amylase digestion, which resulted in depressions and selective opening of the granule. Hot water soluble gum from the endosperm was a noncellulosic beta-D-glucan. A cold water soluble fraction from the hulls was identified as a mixture of arabinogalactans; a hot water soluble fraction was found to be a composite aggregate of water-soluble gums and pectic fractions. Pectic fractions from the hulls had gelling characteristics that were superior to those from the endosperm. Hemicellulose A from the hulls was an amyloid-type polysaccharide, and hemicellulose B was either a glucomannan-type polysaccharide or a mixture of a glucomannan and a cellulosic beta-D-glucan. Glucose was the predominant sugar in hemicelluloses A and B of the endosperm. Alkali-insoluble residue from the endosperm was a macromolecular aggregate of pentosans and cellulose, whereas that from the hulls was composed of cellulose.