Non-starch polysaccharides and bound phenolic acids from native and maltedfinger millet (Ragi, Eleusine coracana, Indaf-15)

Nature of non-starch polysaccharides (NSP) and bound phenolic acids from na tive and malted ragi were studied using a recently-released hybrid variety of ragi, (Indaf-15). Yields of water-soluble NSP, hemicellulose-B and cellu lose polysaccharides increased upon malting whereas a substantial decrease in the yield of hemicellulose-A was observed. Hemicellulose-B is the most v iscogenic and its relative viscosity decreased from 3.04 to 1.98 upon 96 h of malting, whereas the solubility and viscosities of the rest of the NSP i ncreased upon malting. The major sugars identified in all the NSP fractions were arabinose, xylose, galactose and glucose. A one- to two-fold decrease in arabinose was observed in all the NSP upon malting except for the alkal i-insoluble residue wherein a decrease of glucose was observed. A progressi ve decrease in the pentose to hexose ratio was observed, indicating mainly pentosan degradation during malting, whereas an increase in the pentose to hexose ratio was observed in the alkaline-insoluble residue (AIR). Ferulic, caffeic and coumaric acids were identified as the major bound phenolic aci ds in native ragi and one- to two-fold decrease was observed in their conte nts after 4 days of malting. (C) 2001 Elsevier Science Ltd. All rights rese rved.