title: Characterisation of the arabinose-rich carbohydrate composition of immature and mature marama beans (Tylosema esculentum).
abstract: Marama bean (Tylosema esculentum) is an important component of the diet around the Kalahari Desert in Southern Africa where this drought resistant plant can grow. The marama bean contains roughly 1/3 proteins, 1/3 lipids and 1/3 carbohydrates, but despite its potential as dietary supplement little is known about the carbohydrate fraction. In this study the carbohydrate fraction of "immature" and "mature" marama seeds are characterised. The study shows that the marama bean contains negligible amounts of starch and soluble sugars, both far less than 1%. The cell wall is characterised by a high arabinose content and a high resistance to extraction as even a 6M NaOH extraction was insufficient to extract considerable amounts of the arabinose. The arabinose fraction was characterised by arabinan-like linkages and recognised by the arabinan antibody LM6 and LM13 indicating that it is pectic arabinan. Two pools of pectin could be detected; a regular CDTA (1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid) or enzymatically extractable pectin fraction and a recalcitrant pectin fraction containing the majority of the arabinans, of which about 40% was unextractable using 6M NaOH. Additionally, a high content of mannose was observed, possibly from mannosylated storage proteins.
authors.affiliation: Quality and Technology, Department of Food Science, Faculty of Life Sciences, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C, Denmark.
authors.forename: Minah M
authors.initials: MM
authors.lastname: Mosele
authors.forename: Ase S
authors.initials: AS
authors.lastname: Hansen
authors.forename: Søren B
authors.initials: SB
authors.lastname: Engelsen
authors.forename: Jerome
authors.initials: J
authors.lastname: Diaz
authors.forename: Iben
authors.initials: I
authors.lastname: Sørensen
authors.forename: Peter
authors.initials: P
authors.lastname: Ulvskov
authors.forename: William G T
authors.initials: WG
authors.lastname: Willats
authors.forename: Andreas
authors.initials: A
authors.lastname: Blennow
authors.forename: Jesper
authors.initials: J
authors.lastname: Harholt
mesh_terms: D001089:Arabinose / Q000737:chemistry*; D002473:Cell Wall / Q000737:chemistry; D005591:Chemical Fractionation; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D007887:Fabaceae / Q000737:chemistry* / Q000254:growth & development; D006031:Glycosylation; D006868:Hydrolysis; D010368:Pectins / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry; D012639:Seeds / Q000737:chemistry* / Q000254:growth & development; D012995:Solubility
chemical_list: D010940:Plant Proteins; C005390:CDTA; D010368:Pectins; D004492:Edetic Acid; D001089:Arabinose