Cereal Chem 72:648-651 |
Nonstarchy Polysaccharide Analysis of Cotyledon and Hull of Lupinus albus.
A. A. Mohamed and P. Rayas-Duarte. Copyright 1995 by the American Association of Cereal Chemists, Inc.
The cotyledon and hull of a lupin cultivar sample (Lupinus albus L.2043N) were analyzed for polysaccharide composition. Nonstarchy polysaccharides (NSP) were obtained from the whole grain, hull, and cotyledon fractions after defatting and pronase/alpha-amylase hydrolysis. Cotyledon polysaccharides of the water-insoluble fraction (11.7%) contained galactose greater than arabinose greater than mannose. Cotyledon's water-soluble fraction (88.3%) contained galactose greater than mannose greater than arabinose. The presence of galactose and mannose suggested the presence of galactomannan. As expected, a high ratio of galactose to arabinose (3.3) in L. albus L2043N cotyledon indicated a high content of cell wall material. Fractions of cellulose, hemicellulose A and B, and oxalate-soluble material were separated by solubility properties. Arabinose was the dominant sugar in the hull and galactose in the cotyledon. The hull contained 56% NSP, most of which was hemicellulose, which represented 65% of the total NSP in the whole grain. The oxalate- soluble and cellulose fractions were not completely separated from hemicellulose, as indicated by the presence of arabinose and xylose in the former and arabinose in the latter.