Characterisation of the arabinose-rich carbohydrate composition of immature and mature marama beans (Tylosema esculentum)
In alcohol insoluble material of marama beans 40% of the arabinan was recalcitrant to severe alkaline extraction. Mannose from protein glycosylation was also observed. [Display omitted] ► Marama bean has less than 1% starch and soluble sugars. ► Arabinose from arabinan is the main non-cellulosic sug...
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Published in | Phytochemistry (Oxford) Vol. 72; no. 11-12; pp. 1466 - 1472 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier Ltd
01.08.2011
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | In alcohol insoluble material of marama beans 40% of the arabinan was recalcitrant to severe alkaline extraction. Mannose from protein glycosylation was also observed. [Display omitted]
► Marama bean has less than 1% starch and soluble sugars. ► Arabinose from arabinan is the main non-cellulosic sugar in the mature marama bean cell wall. ► Two fractions of pectin was identified, a low and a high recalcitrant fraction.
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. |
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Bibliography: | http://dx.doi.org/10.1016/j.phytochem.2011.03.027 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0031-9422 1873-3700 |
DOI: | 10.1016/j.phytochem.2011.03.027 |