title: Structural features of pectic polysaccharides from the skin of Opuntia ficus-indica prickly pear fruits.
abstract: After removal of the mucilage with water at room temperature, pectic polysaccharides were solubilized from Opuntia ficus-indica fruit skin, by sequential extraction with water at 60 degrees C (WSP) and EDTA solution at 60 degrees C (CSP). Polysaccharides with neutral sugar content of 0.48 and 0.36 mol/mol galacturonic acid residue were obtained, respectively, in the WSP and CSP extracts. These pectic polysaccharides were de-esterified and fractionated by anion-exchange chromatography, yielding for each extract five fractions, which were thereafter purified by size-exclusion chromatography. Two of these purified fractions were characterized by sugar analysis combined with methylation and reduction-methylation analysis. The study was then supported by (1)H and (13)C NMR spectroscopy. The results showed that the water-soluble fraction WSP3 and the EDTA soluble fraction CSP3, consisted of a disaccharide repeating unit -->2)-alpha-l-Rhap-(1-->4)-alpha-d-GalpA-(1--> backbone, with side chains attached to O-4 of the rhamnosyl residues. The side chains contained highly branched alpha-(1-->5)-linked arabinan and short linear beta-(1-->4)-linked galactan.
authors.affiliation: Centre de Recherches sur les Macromolécules Végétales, C.N.R.S., and Université Joseph Fourier, BP 53, 38041 Grenoble cedex 9, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Habibi
authors.forename: A
authors.initials: A
authors.lastname: Heyraud
authors.forename: M
authors.initials: M
authors.lastname: Mahrouz
authors.forename: M R
authors.initials: MR
authors.lastname: Vignon
mesh_terms: D000838:Anions; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000378:metabolism; D002845:Chromatography; D002852:Chromatography, Ion Exchange; D004492:Edetic Acid / Q000737:chemistry; D005685:Galactans / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D029747:Opuntia; D010368:Pectins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014574:Uronic Acids / Q000737:chemistry
chemical_list: D000838:Anions; D005685:Galactans; D006603:Hexuronic Acids; D011134:Polysaccharides; D014574:Uronic Acids; C030080:araban; C007819:galacturonic acid; D010368:Pectins; D004492:Edetic Acid