Du är här

Characterization of acetylated 4-O-methylglucuronoxylan isolated from aspen employing 1H and 13C NMR spectroscopy

Författare:
Publiceringsår: 2000
Språk: Engelska
Sidor: 807-815
Publikation/Tidskrift/Serie: Carbohydrate Research
Volym: 329
Nummer: 4
Dokumenttyp: Artikel
Förlag: Elsevier

Sammanfattning

Water-soluble hemicelluloses were extracted from milled aspen wood (Populus tremula) employing microwave oven treatment at 180oC for 10 min. The final pH of this extract was 3.5. From this extract oligo- and polysaccharides were isolated and subsequently fractionated by size-exclusion chromatography. The structures of the saccharides in three of the fractions obtained were determined by 1H and 13C NMR spectroscopy, using homonuclear and heteronuclear two-dimensional techniques. The polysaccharides present in the two fractions eluted first were O-acetyl-(4-O-methylglucurono)xylans. The average degree of acetylation of the xylose residues in these compounds was 0.6. The structural element ->4)4-O-Me-α-d-GlcpA-(1->2)3-O-Ac-β-d-Xylp-(1-> could also be identified. On the average, these two xylans were composed of the following (1->4)-linked β-d-xylopyranosyl structural elements: unsubstituted (50 mol%), 2-O-acetylated (13 mol%), 3-O-acetylated (21 mol%), 2,3-di-O-acetylated (6 mol%) and MeGlcA α-(1->2)3-O-acetylated (10 mol%). Most of the 4-O-methylglucuronyl and acetyl substituents in the isolated polysaccharides survived the microwave oven treatment. The third fraction, eluted last, contained acetylated xylo-oligosaccharides, with minor contamination by an acetylated mannan. In the case of these xylo-oligosaccharides, the average degree of acetylation was 0.3.

Disputation

Nyckelord

  • Chemistry
  • Aspen wood (Populus tremula)
  • Hemicellulose
  • Xylan
  • extraction
  • structure
  • O-Acetylation
  • fractionation
  • Microwave oven

Övrigt

Published
Yes
  • ISSN: 0008-6215

Box 117, 221 00 LUND
Telefon 046-222 00 00 (växel)
Telefax 046-222 47 20
lu [at] lu [dot] se

Fakturaadress: Box 188, 221 00 LUND
Organisationsnummer: 202100-3211
Om webbplatsen

LERU logo U21 logo