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Novel arabinan and galactan oligosaccharides from dicotyledonous plants.

Wefers D, Tyl CE, Bunzel M - Front Chem (2014)

Bottom Line: To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment.Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized.The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology Karlsruhe, Germany.

ABSTRACT
Arabinans and galactans are neutral pectic side chains and an important part of the cell walls of dicotyledonous plants. To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment. LC-MS(2) and one- and two-dimensional NMR spectroscopy were used for unambiguous structural characterization. It was demonstrated that arabinans contain β-(1→3)-linked arabinobiose as a side chain in quinoa seeds, while potato galactan was comprised of β-(1→4)-linked galactopyranoses which are interspersed with α-(1→4)-linked arabinopyranoses. Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized. The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

No MeSH data available.


CID MS2 mass spectrum of lithium cationized compound 1 (m/z 685).
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Figure 1: CID MS2 mass spectrum of lithium cationized compound 1 (m/z 685).

Mentions: Quinoa insoluble fiber was hydrolyzed with endo-arabinanase, and the hydrolyzate was fractionated using Bio-Gel P2 chomatography. Semipreparative HPLC purification of the corresponding fractions yielded compound 1 in sufficient amounts and purity for further analysis. Monosaccharide analysis showed that l-arabinose was the only monosaccharide present. LC-PGC-MS of the lithium-cationized oligosaccharide showed a quasimolecular ion with m/z 685, indicating an arabinose pentamer. Since endo-arabinanase should be able to cleave a linear pentamer, the isolated pentamer was hypothesized to be branched. This hypothesis was supported by the MS2 spectrum (Figure 1). Westphal et al. (2010b) showed that cross ring cleavages are the source of the main fragments of linear arabinooligosaccharides, while MS2 spectra of branched oligosaccharides show higher intensities from interglycosidic cleavages. The dominating fragment ion is m/z 553 (mass loss of 132 Da), which corresponds to the loss of an anhydro-arabinose. The 60 Da (m/z 625) and 90 Da (m/z 595) mass losses result from cross ring cleavage through the reducing unit. Because these fragments are of a much lower intensity than the interglycosidic cleavage fragment, compound 1 seems to be a branched arabinan pentamer.


Novel arabinan and galactan oligosaccharides from dicotyledonous plants.

Wefers D, Tyl CE, Bunzel M - Front Chem (2014)

CID MS2 mass spectrum of lithium cationized compound 1 (m/z 685).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4226231&req=5

Figure 1: CID MS2 mass spectrum of lithium cationized compound 1 (m/z 685).
Mentions: Quinoa insoluble fiber was hydrolyzed with endo-arabinanase, and the hydrolyzate was fractionated using Bio-Gel P2 chomatography. Semipreparative HPLC purification of the corresponding fractions yielded compound 1 in sufficient amounts and purity for further analysis. Monosaccharide analysis showed that l-arabinose was the only monosaccharide present. LC-PGC-MS of the lithium-cationized oligosaccharide showed a quasimolecular ion with m/z 685, indicating an arabinose pentamer. Since endo-arabinanase should be able to cleave a linear pentamer, the isolated pentamer was hypothesized to be branched. This hypothesis was supported by the MS2 spectrum (Figure 1). Westphal et al. (2010b) showed that cross ring cleavages are the source of the main fragments of linear arabinooligosaccharides, while MS2 spectra of branched oligosaccharides show higher intensities from interglycosidic cleavages. The dominating fragment ion is m/z 553 (mass loss of 132 Da), which corresponds to the loss of an anhydro-arabinose. The 60 Da (m/z 625) and 90 Da (m/z 595) mass losses result from cross ring cleavage through the reducing unit. Because these fragments are of a much lower intensity than the interglycosidic cleavage fragment, compound 1 seems to be a branched arabinan pentamer.

Bottom Line: To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment.Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized.The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology Karlsruhe, Germany.

ABSTRACT
Arabinans and galactans are neutral pectic side chains and an important part of the cell walls of dicotyledonous plants. To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment. LC-MS(2) and one- and two-dimensional NMR spectroscopy were used for unambiguous structural characterization. It was demonstrated that arabinans contain β-(1→3)-linked arabinobiose as a side chain in quinoa seeds, while potato galactan was comprised of β-(1→4)-linked galactopyranoses which are interspersed with α-(1→4)-linked arabinopyranoses. Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized. The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

No MeSH data available.