Variation in the degree of D-xylose substitution in water-extractable European durum wheat (Triticum durum desf.) semolina arabinoxylans

J Agric Food Chem. 1999 May;47(5):1813-6. doi: 10.1021/jf981130i.

Abstract

Durum wheat (Triticum durum Desf.) semolina water-extractable arabinoxylan (TWEAX) (yield 0.28%, arabinose-to-xylose ratio (A/X) 0. 62) was fractionated by a stepwise increase in ethanol concentration (up to 65%). The A/X ratios of the resulting fractions varied between 0.42 and 0.80. With increasing ethanol concentrations, increasing A/X ratios went hand in hand with a relative increase of low molecular weight compounds, indicating that high molecular weight compounds with a low A/X ratio are preferentially precipitated from alcohol/water mixtures. (1)H NMR showed that, whereas in TWEAX the levels of unsubstituted xyloses (X(0)), monosubstituted (X(1)), and disubstituted (X(2)) xyloses were 63.1%, 11.8%, and 25.1%, respectively, fractions that precipitated with increasing ethanol concentrations had decreasing levels of X(0). Simultaneously, the level of X(1) decreased equally until it leveled of at ca. 10%. Concomitantly, the level of X(2) increased. The levels of X(0), X(1), and X(2) varied between 69.7% and 53.4%, 18.2% and 10.7%, and 12.2% and 35.9%, respectively.

MeSH terms

  • Arabinose / analysis
  • Chromatography, Gel
  • Europe
  • Flour / analysis
  • Triticum / chemistry*
  • Xylans / chemistry*
  • Xylose / analysis*

Substances

  • Xylans
  • arabinoxylan
  • Xylose
  • Arabinose