title: Characterization of a water soluble, hyperbranched arabinogalactan from yacon (Smallanthus sonchifolius) roots.
abstract: Yacon (Smallanthus sonchifolius Poepp. & Endl.) roots are largely grown in Andean countries and have attracted recent interest due to their antioxidant and prebiotic effects. Yacon is typically consumed as a fruit due to its sweet taste and juiciness. The macromolecular properties of an aqueous extract of yacon are investigated using asymmetric flow field-flow fractionation (AF4) coupled to UV, multiangle light scattering (MALS) and differential refractive index (dRI) detection. The method allows for determination of molar mass and size over the size distribution. Three major populations were found of which one strongly dominates in concentration. Through collection of fractions from AF4, carbohydrate composition and glycosidic linkage analysis for the dominating population was performed. The results show that the dominating population consists of a highly branched arabinogalactan (type 2) with a molar mass of approximately 1-2·105g/mol, a hydrodynamic radius of approximately 6-10nm and a relatively high apparent density (approx. 70-150kg/m3).
authors.affiliation: Department of Food Technology, Engineering and Nutrition, Lund University, P.O. Box 124, SE-222 01 Lund, Sweden; Center for Food and Natural Products, San Simón University, Cochabamba, Bolivia.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Castro
authors.affiliation: Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Centre, SE-106 91 Stockholm, Sweden.
authors.forename: Francisco
authors.initials: F
authors.lastname: Vilaplana
authors.affiliation: Department of Food Technology, Engineering and Nutrition, Lund University, P.O. Box 124, SE-222 01 Lund, Sweden. Electronic address: lars.nilsson@food.lth.se.
authors.forename: Lars
authors.initials: L
authors.lastname: Nilsson
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000737:chemistry; D019659:Asteraceae; D031521:Fractionation, Field Flow / Q000379:methods; D005685:Galactans / Q000032:analysis* / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*; D056692:Prebiotics / Q000032:analysis; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005685:Galactans; D010936:Plant Extracts; D056692:Prebiotics; D014867:Water; C005653:arabinogalactan
keywords: AF4; Arabinogalactan; Asymmetric flow field-flow fractionation; Smallanthus sonchifolius; Yacon