title: Structure and solution properties of tamarind-seed polysaccharide.
abstract: The major polysaccharide in tamarind seed is a galactoxyloglucan for which the ratios galactose:xylose:glucose are 1:2:25:2.8. A minor polysaccharide (2-3%) contains branched (1----5)-alpha-L-arabinofuranan and unbranched (1----4)-beta-D-galactopyranan features. Small-angle X-ray scattering experiments gave values for the cross-sectional radius of the polymer in aqueous solution that were typical of single-stranded molecules. Marked stiffness of the chain (C infinity 110) was deduced from static light-scattering studies and is ascribed partially to the restriction of the motion of the (1----4)-beta-D-glucan backbone by its extensive (approximately 80%) glycosylation. The rigidity of the polymer caused significant draining effects which heavily influenced the hydrodynamic behaviour. The dependence of "zero-shear" viscosity on concentration was used to characterise "dilute" and "semi-dilute" concentration regimes. The marked dependence on concentration in the "semi-dilute" region was similar to that for other stiff neutral polysaccharide systems, ascribed to "hyper-entanglements", and it is suggested that these may have arisen through a tenuous alignment of stiffened chains.
authors.affiliation: Unilever Research Laboratory, Great Britain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gidley
authors.forename: P J
authors.initials: PJ
authors.lastname: Lillford
authors.forename: D W
authors.initials: DW
authors.lastname: Rowlands
authors.forename: P
authors.initials: P
authors.lastname: Lang
authors.forename: M
authors.initials: M
authors.lastname: Dentini
authors.forename: V
authors.initials: V
authors.lastname: Crescenzi
authors.forename: M
authors.initials: M
authors.lastname: Edwards
authors.forename: C
authors.initials: C
authors.lastname: Fanutti
authors.forename: J S
authors.initials: JS
authors.lastname: Reid
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010944:Plants / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D014783:Viscosity; D014990:Xylans
chemical_list: D005936:Glucans; D011134:Polysaccharides; D014990:Xylans; C029353:xyloglucan