Hydrolysis and Fermentation by Rat Gut Microorganisms of 2-O-β-D-Xylopyranosyl (5-O-Feruloyl)-L-Arabinose Derived from Grass Cell Wall Arabinoxylan
✍ Scribed by Wende, Gundolf; Buchanan, Callum J; Fry, Stephen C
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 295 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
It has been shown that a common side-chain of grass cell wall arabinoxylans is 2-O-b-D-xylopyranosyl-(5-O-feruloyl)-L-arabinose [X(F)A]. The stability of X(F)A was determined by incubation of ( feruloyl-U-14C)-labelled X(F)A and (pentosyl-1-3H)-labelled X(F)A anaerobically with rat caecal contents and chromatographic analysis of the radioactive products. The ester linkage was hydrolysed very rapidly to form ferulic acid (which was stable) and the disaccharide (XA). The 3H-XA was further metabolised, but 3H-monosaccharides did not accumulate. In the end-products of fermentation of (pentosyl-3H)-labelled X(F)A, 67% of the 3H was present in bacterial polymers. In contrast, when free [1-3H] arabinose was incubated with rat caecal contents, 74% of the 3H quickly became volatile, probably as It is concluded that X(F)A is highly susceptible to 3H 2 O. (feruloyl)esterase activity produced by bacteria present in the rat caecum, and that the disaccharide produced is further fermented, but not via the production of extracellular arabinose and xylose.