Cereal Chem 54:746 - 759.  |  VIEW ARTICLE
Water-Soluble Nonstarchy Polysaccharides of Composite Flours. I. Chemical Nature of Polysaccharides from Yam (Dioscorea) and Cassava Flours.

S. Sefa-Dedeh and V. F. Rasper. Copyright 1977 by the American Association of Cereal Chemists, Inc. 

Gas-liquid chromatographic analysis of derived hydrolysates of water-soluble nonstarchy polysaccharides (W.S.N.P.) extracted from flours milled from dried tubers of three species of yam (Dioscorea rotundata Poir., D. alata L., and D. Cayenensis Lam.) and roots of cassava (Manihot utilissima Pohl., Cv. Ankra) revealed marked differences in their composition. While D-glucose was the major component of material extracted from cassava flour, W.S.N.P. of D. alata L. and D. cayenensis Lam. origin were characterized by a high concentration of D-mannose, which accounted for almost 50% of their total carbohydrate content. Though Pentoses were present in all tested samples, D. rotundata Poir. W.S.N.P. were the only ones in which 5-carbon ring sugars formed the major fraction; they represented 57% of the total carbohydrate content with arabinose being the major component. The uronic acid content in all extracted materials was relatively high, reaching over 24% in W.S.N.P. of D. rotundata Poir. flour. Viscometric measurements on unoxidized and oxidized solutions and uv absorption analysis indicated behavior similar to that characteristic of woater-soluble wheat flour 'pentosans.' Data obtained by uv absorption analysis and thin- layer chromatography provided evidence for the involvement of a phenolic compound in the oxidative gelation of these solutions. The presence of ferulic acid and other phenolic acids in the tested materials was confirmed by thin-layer chromatograpy.