THE CARBOHYDRATE-COMPOSITION OF COTYLEDONS AND HULLS OF CULTIVARS OF LUPINUS-ANGUSTIFOLIUS FROM WESTERN-AUSTRALIA

The hulls and cotyledons from three Western Australian cultivars (Gung urru, Yorrel and Danja) of Lupinus angustifolius, all of low alkaloid content, were analysed separately for their carbohydrate content and c omposition. Only minor differences in composition between these three cultivars were observed. More notably, the cotyledons of all the culti vars contained levels of non-starch polysaccharides (NSP), ranging fro m 290 to 310 g kg-1 dry weight considerably higher than had been measu red previously in cultivars of this species. Galactose, arabinose and uronic acid residues accounted for approximately 67%, 13% and 10%, res pectively, of the cotyledon NSP. Although only a small proportion of t he cotyledon NSP is soluble, a much larger proportion could be extract ed with hot EDTA treatment. The oligosaccharide content of the cotyled ons ranged from 74 to 80 g kg-1 dry weight. Cotyledons had very low co ntents of cellulose, lignin and starch. Hulls consisted predominantly of NSP, with values ranging from 856 to 891 g kg-1 dry weight. Glucose , xylose, uronic acids and arabinose were the principal sugar residues present reflecting the compositions of the major constituent polysacc harides, cellulose, hemicelluloses and pectins. Only low levels of lig nin were measured in hulls. Cotyledon NSP and hulls from these cultiva rs may have considerable value as sources of dietary fibre in the huma n diet.