Hostname: page-component-745bb68f8f-g4j75 Total loading time: 0 Render date: 2025-01-14T19:53:50.505Z Has data issue: false hasContentIssue false
  • English
  • Français

Molecular weight, tertiary structure, water binding and colon behaviour of ispaghula husk fibre

Published online by Cambridge University Press:  05 March 2007

Saphwan Al-Assaf ,
Glyn O. Phillips ,
Peter A. Williams ,
Shoji Takigami ,
Peter Dettmar  and
Michael Havler
Saphwan Al-Assaf
Affiliation:
The North East Wales Institute, Plus Coch, Mold Road, Wrexham, LL1 2AW, UK
Glyn O. Phillips*
Affiliation:
The North East Wales Institute, Plus Coch, Mold Road, Wrexham, LL1 2AW, UK
Peter A. Williams
Affiliation:
The North East Wales Institute, Plus Coch, Mold Road, Wrexham, LL1 2AW, UK
Shoji Takigami
Affiliation:
University of Gunma, Kiryu, Gunma-ken, Japan
Peter Dettmar
Affiliation:
University of Gunma, Kiryu, Gunma-ken, Japan
Michael Havler
Affiliation:
Reckitt Benckiser pic, Dansom Lane, Kingston upon Hull, HU8 7DS, UK
*
*Corresponding author: Professor Glyn O. Phillips, Present address: Research Transfer Ltd, 2 Plymouth Drive, Radyr, CardiffCF15 8BL, fax +44 29 20 843145, phillipsglyn@aol.com
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Molecular variables, using aqueous and alkaline extracts, of the polysaccharide from ispaghula husk (IH) were examined using gel-permeation chromatography linked to multi-angle laser light scattering. Progressive extraction can yield a component with a molecular weight (MW) value up to about 7×106 Da, and gels, which accompany the extraction, have MW ranging from 10–20× 106 Da. To mimic the polysaccharide degradation, particularly in the colon, the solid IH was degraded progressively using ionising radiation. A chain break occurs every 7.5 kGy in NaOH and every 15 kGy in water. The solid-state matrix is opened by the radiation to yield increased visco-elasticity of the aqueous extracts at critical radiation doses, before further degradation occurs after about 12 kGy. Differential scanning calorimetry is used to study the mechanism of interaction of water with IH. The first water to be taken up is non-freezing water and represents about twelve water molecules/disaccharide unit of the polysaccharide. As the water content is increased, the water becomes bound to the polysaccharide and freezes and melts at a temperature different from free water. This water is thermodynamically distinguishable from free water. It forms amorphous ice on cooling which crystallises exothermically and subsequently melts endothermically. Saturation occurs at a water content of 2–3 g water/g polymer, showing that about 60% of the water in the system is ‘bound’. The most surprising conclusion is that despite the fact that the IH swells in water to form a solid and stiff gel, the greater part of that water in the gel is still free and behaves like liquid water.

Keywords

Non-starch polysaccharidesIspaghula huskColonGel permeation chromatographyMulti-angle laser light scattering
Type
Session: Physiological aspects of fibre
Information
Proceedings of the Nutrition Society , Volume 62 , Issue 1 , February 2003 , pp. 211 - 216
Copyright
Copyright © The Nutrition Society 2003

References

Al-Assaf, S, Williams, PA & Phillips, GO (2002) The molecular characterisation of hyaluronan and hylan. In Hyaluronan 2000. Vol. 1, Chemical, Biochemical and Biological Aspects, pp.55–74. [Kennedy, JF, Phillips, GO, Williams, PA, Hascall, VC, editors]. Cambridge: Woodhead Publishing.CrossRefGoogle Scholar
Marteau, P, Flourie, B, Cherbut, C, Correze, JL, Pellier, P, Seyklaz, J, Rabbaud, JC (1994) Digestibility and bulking effect of ispaghula husks in healthy humans. Gut 25, 1747–1752.CrossRefGoogle Scholar
Milas, M, Rinaudo, M, Rours, R, Al-Assaf, S, Phillips, GO, Williams, PA (2001) Comparative behaviour of hyaluronan from bacterial and animal sources with cross-linked hyaluronan (Hy lan) in aqueous solution. Biopolymers 59, 191–204.3.0.CO;2-M>CrossRefGoogle Scholar
Takigami, S, Takigami, M, Phillips, GO (1995) Effect of preparation method on the hydration characteristics of hylan and comparison with another highly cross-linked polysaccharide, gum arabic. Carbohydrate Polymers 26, 11–18.Google Scholar
Viebke, C, Williams, PA (2000) Determination of molecular mass distribution of k-carrageenan and xanthan using asymmetrical flow field-flow fractionation. Food Hydrocolloids 14, 265–270.CrossRefGoogle Scholar
Wahlund, K-G, Gustavsson, M, MacRitchie, F, Nylander, T, Wannerberger, L (1996) Size characterisation of wheat proteins, particularly glutenin, by asymmetrical flow field flow fraction- ation. Journal of Cereal Science 23, 113–119.CrossRefGoogle Scholar
Wittgren, B, Wahlund, K-G, Derand, H, Wesslen, B (1996) Size characterisation of a charged amphiphilic copolymer in solutions of different salts and salt concentrations using flow field-flow fractionation. Langmuir 12, 5999–6005.Google Scholar