Chemical structures of green coffee beans polysaccharides
The chemical structures of green coffee bean polysaccharides have been determined by methylation analysis of whole beans and of extracted polymer-rich fractions. Ground beans were completely solubilized in 4-methylmorpholine N-oxide, and the Hakomori methylation procedure was applied directly. The polysaccharide fraction in Robusta beans constitutes 48 percent of the dry weight and is principally composed of three polymers: arabinogalactan, mannan, cellulose. The arabinogalactan has a Beta 1 -> 3-linked galactan main chain with frequent arabinose and galactose residue containing side chains, whereas the mannan resembles cellulose in that it has a linear Beta 1 -> 4-linked structure. Only occasional single-residue galactose side chains are present in the mannan fraction. Polysaccharide compositions of Robusta and Arabica beans are similar; the only significant difference is the higher content (approximately 3 percent) of arabinogalactan in the former type
| Main Authors: | , |
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| Format: | biblioteca |
| Published: |
Feb
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| Subjects: | COFFEA ARABICA, COFFEA CANEPHORA, CAFE VERDE, POLISACARIDOS, ESTRUCTURA QUIMICA, COMPOSICION, |
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