TY - JOUR
T1 - Characterisation of the arabinose-rich carbohydrate composition of immature and mature marama beans (Tylosema esculentum)
AU - Mosele, Minah Mmoni
AU - Hansen, Åse Solvej
AU - Engelsen, Søren Balling
AU - Diaz, Jerome Villarama
AU - Sørensen, Iben
AU - Ulvskov, Peter
AU - Willats, William George Tycho
AU - Blennow, Per Gunnar Andreas
AU - Harholt, Jesper
PY - 2011/8
Y1 - 2011/8
N2 - 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 6 M 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 6 M NaOH. Additionally, a high content of mannose was observed, possibly from mannosylated storage proteins.
AB - 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 6 M 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 6 M NaOH. Additionally, a high content of mannose was observed, possibly from mannosylated storage proteins.
U2 - 10.1016/j.phytochem.2011.03.027
DO - 10.1016/j.phytochem.2011.03.027
M3 - Journal article
C2 - 21543095
SN - 0031-9422
VL - 72
SP - 1466
EP - 1472
JO - Phytochemistry
JF - Phytochemistry
IS - 11-12
ER -