Structural features of the cell-wall polysaccharides of Asparagus officinalis seeds.

The fine structure of a beta-)1----4)-linked glucomannan from Asparagus officinalis has been determined by n.m.r. analysis of the oligosaccharides obtained by acidic and enzymic hydrolyses. Cleavage of the glucomannan with beta-D-mannase from Aspergillus niger and purification by h.p.l.c. gave oligosaccharide fractions that contained Man (mannose), GlcMan (beta-glucopyranosylmannose), Man2, Glc2Man, and Glc3Man as the major components. Simulated digestion of a polymer composed of randomly distributed monomers with the same Glc:Man ratio as glucomannan from A. officinalis led to the same polysaccharides. The random distribution of the monomers of glucomannan from A. officinalis was corroborated by the diffraction diagram of the raw flour, which indicated that the "in situ" glucomannan was amorphous, whereas both cellulose and mannans are crystalline.