title: Determination of the uronic acid composition of seaweed dietary fibre by HPLC.
abstract: A high-performance liquid chromatographic (HPLC) method is described for determination of the ratio of beta-d-mannuronic acid to alpha-l-guluronic acid (M/G ratio) in dietary fibre of edible seaweeds. Total dietary fibre (TDF) content was determined gravimetrically. The TDF fraction was hydrolysed with 12 m and 1 m H(2)SO(4), then neutralized with AG 4 x 4 resin. The uronic acids were separated in a Tracer Extrasil SAX 5 micro m column (25 cm x 4 mm) at 35 degrees C, with 2 mm KH(2)PO(4) containing 5% methanol as mobile phase at a fl ow rate of 1.5 mL/min. The detection wavelength was UV 210 nm. The chromatographic identifications of beta-d-mannuronic acid and alpha-l-guluronic acid were confirmed by liquid chromatography-mass spectrometry (LC-MS). The method precision was 1.4% for beta-d-mannuronic acid and 3.5% for alpha-l-guluronic acid. The method was used to determine M/G ratio in canned seaweeds (Saccorhiza polyschides and Himanthalia elongata) and in dried seaweeds (H. elongata, Laminaria ochroleuca, Undaria pinnatifida, Palmaria sp. and Porphyra sp.).
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, La Coruña, Spain.
authors.forename: D I
authors.initials: DI
authors.lastname: Sánchez-Machado
authors.forename: J
authors.initials: J
authors.lastname: López-Cervantes
authors.forename: J
authors.initials: J
authors.lastname: López-Hernández
authors.forename: P
authors.initials: P
authors.lastname: Paseiro-Losada
authors.forename: J
authors.initials: J
authors.lastname: Simal-Lozano
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004043:Dietary Fiber / Q000032:analysis*; D013058:Mass Spectrometry; D012624:Seaweed / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014574:Uronic Acids / Q000032:analysis*
chemical_list: D004043:Dietary Fiber; D014574:Uronic Acids