title: Structural characterization of mesquite (Prosopis velutina) gum and its fractions.
abstract: Structural and physicochemical characteristics of mesquite gum (from Prosopis velutina) were investigated using FT-IR spectroscopic, mass spectrometric and chromatographic methods. Four fractions (F-I, F-IIa, F-IIb and F-III) were isolated by hydrophobic interaction chromatography. The samples were characterized and analyzed for their monosaccharide and oligomers composition by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). L-Arabinose (L-Ara) and D-galactose (D-Gal) were found as the main carbohydrate constituent residues in the polysaccharides from mesquite gum and their ratio (L-Ara/D-Gal) varied within the range 2.54 to 3.06 among the various fractions. Small amounts of D-glucose (D-Glc), D-mannose (D-Man) and D-xylose (D-Xyl) were also detected, particularly in Fractions IIa, IIb and III. Infrared spectroscopy identified polysaccharides and protein in all the samples. Data from mass spectrometry (MALDI-TOF MS) was consistent with the idea that the structure corresponding to the periphereal chains of Fraction I is predominantly a chain of pentoses attached to uronic acid.
authors.affiliation: Laboratory of Biopolymers, Centro de Investigación en Alimentación y Desarrollo, P.O. Box 1735, Hermosillo, Sonora 83000, Mexico.
authors.forename: Yolanda L
authors.initials: YL
authors.lastname: López-Franco
authors.forename: Ana M Calderón
authors.initials: AM
authors.lastname: de la Barca
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Valdez
authors.forename: Martin G
authors.initials: MG
authors.lastname: Peter
authors.forename: Marguerite
authors.initials: M
authors.lastname: Rinaudo
authors.forename: Gérard
authors.initials: G
authors.lastname: Chambat
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Goycoolea
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006601:Hexoses / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods; D053149:Plant Gums / Q000032:analysis*; D029862:Prosopis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D006601:Hexoses; D053149:Plant Gums; C416517:prosopis gum