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Abstract:The hulls and cotyledons from three Western Australian cultivars (Gungurru, Yorrel and Danja) of Lupinus angustfolius, all of low alkaloid content, were analysed separately for their carbohydrate content and composition.Only minor differences in composition between these three cultivars were observed. More notably, the cotyledons of all the cultivars contained levels of non-starch polysaccharides (NSP), ranging from 290 to 310 g kg-' dry weight considerably higher than had been measured previously in cultivars of this species. Galactose, arabinose and uronic acid residues accounted for approximately 67%, 13% and 10 %, respectively, of the cotyledon NSP. Although only a small proportion of the cotyledon NSP is soluble, a much larger proportion could be extracted with hot EDTA treatment. The oligosaccharide content of the cotyledons ranged from 74 to 80 g kg-' dry weight. Cotyledons had very low contents of cellulose, lignin and starch. Hulls consisted predominantly of NSP, with values ranging from 856 to 891 g kg-' dry weight. Glucose, xylose, uronic acids and arabinose were the principal sugar residues present reflecting the compositions of the major constituent polysaccharides, cellulose, hemicelluloses and pectins. Only low levels of lignin were measured in hulls. Cotyledon NSP and hulls from these cultivars may have considerable value as sources of dietary fibre in the human diet.

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The four recombinant glucosyltransferases (GTFs), GtfJ, GtfK, GtfL and GtfM, that had previously been cloned from Streptococcus salivarius ATCC 25975, were individually expressed in Escherichia coli and their glucan products and kinetic properties were analysed. GtfJ was a primer-dependent GTF which synthesized an insoluble glucan composed mainly of a-(1 + 3)-linked glucosyl residues in the presence of dextran 1-10. GtfK was primer-stimulated, and produced a linear soluble dextran without any detectable branch points both in the absence and in the presence of dextran 1-10. GtfL was primerindependent and produced a mixed-linkage insoluble glucan composed of approximately equal proportions of a-(l-+ 3)-and a-(1 + 6)-linked glucosyl residues. GtfL was inhibited by dextran T-10. G t f M was primer-independent and produced a soluble dextran with approximately 5% a-(1 + 3)-linked glucosyl residues. G t f M was essentially unaffected by the presence of dextran T-10. The results confirmed that each enzyme represented one of the four possible combinations of primer-dependency and product solubility and that each possessed unique biosynthetic properties. The soluble dextrans formed by GtfK and GtfM, as well as the mixed-linkage insoluble glucan formed by GtfL, were also capable of acting as primers for the primer-dependent GtfJ and the primer-stimulated GtfK. Unexpectedly, the linear dextran produced by GtfK was by far the least effective either at priming itself or at activating and priming the pr i mer-de pendent GtfJ .

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