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Identification of the acidic degradation products of hexenuronic acid and characterisation of hexenuronic acid-substituted xylooligosaccharides by NMR spectroscopy

✍ Scribed by Anita Teleman; Tiina Hausalo; Maija Tenkanen; Tapani Vuorinen

Publisher: Elsevier Science
Year: 1996
Tongue: English
Weight: 548 KB
Volume: 280
Category: Article
ISSN: 0008-6215
DOI: 10.1016/0008-6215(95)00309-6

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✦ Synopsis

A 4-O-methylglucuronoxylan was converted into a hexenuronoxylan at high temperature and alkalinity similar to the conditions used during kraft pulping. The hexenuronoxylan was hydrolysed with enzymes, and acidic xylooligosaccharides were separated from the hydrolysate by anion-exchange and size-exclusion chromatography. The primary structure of the two main hexenuronic acid-substituted xylooligosaccharides (a tetramer and a pentamer) was determined by two-dimensional 1H and 13C NMR spectroscopy. The 4-deoxy-hexenuronic acid is not stable under the acid hydrolysis step of conventional carbohydrate analysis. Here, we have identified the acidic degradation products of 4-deoxy-hexenuronic acid by NMR spectroscopy. Two degradation pathways were observed, both resulting in a furan derivative.

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