title: Structural characterisation and rheological properties of a polysaccharide from sesame leaves (Sesamum radiatum Schumach. & Thonn.).
abstract: A polysaccharide from the leaves of Sesamum radiatum was extracted by maceration in deionized water followed by ethanol precipitation then chemically and physically characterised. Monosaccharide composition and linkages were determined by high performance anion exchange chromatography (HPAEC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy respectively. Sesamum gum was composed of glucuronic acid, mannose, galactose, and xylose with trace quantities of glucose, rhamnose and arabinose. Proton and (13)C NMR spectroscopy, and linkage analysis revealed a glucuronomannan based structure comprising a backbone of →4)-β-d-GlcpA-(1→2)-α-d-Manp-(1→ with side-chains of galactose and xylose. Hydrated sesamum gum displayed temperature independent viscoelastic properties with no thermal hysteresis. Intrinsic viscosity was determined to be 3.31 and 4.40dLg(-1) in 0.1M NaCl and deionised water respectively, while the critical concentration was determined to be 0.1% w/v. The characterisation performed in this study will help direct potential applications of this material in foods and pharmaceuticals.
authors: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK; Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, University of Jos, Nigeria.
authors: E I
authors: EI
authors: Nep
authors: The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5040, New Zealand.
authors: S M
authors: SM
authors: Carnachan
authors: Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, University of Jos, Nigeria.
authors: N C
authors: NC
authors: Ngwuluka
authors: Department of Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
authors: V
authors: V
authors: Kontogiorgos
authors: Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
authors: G A
authors: GA
authors: Morris
authors: The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5040, New Zealand. Electronic address: ian.sims@vuw.ac.nz.
authors: I M
authors: IM
authors: Sims
authors: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK. Electronic address: a.m.smith@hud.ac.uk.
authors: A M
authors: AM
authors: Smith
mesh_terms: D002236:Carbohydrate Conformation; D018515:Plant Leaves / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification*; D031685:Sesamum / Q000737:chemistry*
chemical_list: D011134:Polysaccharides
keywords: Neutral sugars; Polysaccharide; Rheology; Sesamum; Sesamum radiatum; Uronic acid