Structural characterization and rheological properties of a galactomannan from Astragalus gombo Bunge seeds harvested in Algerian Sahara

Abstract : A water soluble polysaccharide (WSP) was extracted and purified from Astragalus gombo seeds (Fabaceae) harvested in Septentrional Sahara (Ouargla, Algeria) with a yield of 6.8% (w/w of the dry seed ground). It was characterized by gas chromatography coupled to the mass spectrometry (GC–MS), size exclusion chromatography with Multi-Angle Light Scattering analysis (SEC-MALLS), high–resolution 1H and 13C NMR, and rheological measurements. The structural characterization indicated that this WSP fraction is a galactomannan with a mannose/galactose ratio of 1.7 formed by a backbone of β-(1,4)-d-mannopyranosyl residues (63%) substituted at O-6 position by a single α-galactopyranose residue (37%). SEC-MALLS analysis revealed that this galactomannan has an average molecular mass (Mw) of 1.1 × 106 g/mol, an intrinsic viscosity of 860 mL/g and, a random coil conformation structure. Rheological analysis in semi diluted regimes shown pseudo-plastic and viscoelastic behaviour.
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Carbohydrate Polymers, Elsevier, 2017, 175, pp.387 - 394. 〈10.1016/j.carbpol.2017.08.003〉
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https://hal-clermont-univ.archives-ouvertes.fr/hal-01658277
Contributeur : Guillaume Pierre <>
Soumis le : jeudi 7 décembre 2017 - 14:59:48
Dernière modification le : mardi 5 juin 2018 - 10:14:33

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Toufik Chouana, Guillaume Pierre, Christophe Vial, Christine Gardarin, Anne Wadouachi, et al.. Structural characterization and rheological properties of a galactomannan from Astragalus gombo Bunge seeds harvested in Algerian Sahara. Carbohydrate Polymers, Elsevier, 2017, 175, pp.387 - 394. 〈10.1016/j.carbpol.2017.08.003〉. 〈hal-01658277〉

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