Distribution and structural variation of arabinoxylans in common wheat mill streams.
In 19 wheat-milling fractions total pentosan content, calculated as 0.88 x (% L-arabinose + % D-xylose), varied between 1.44 and 30.66% on dry matter (dm). It increased with ash content once the latter exceeded 0.6% (dm basis). Water-extractable arabinoxylans were recovered by saturating water extracts to 65% ethanol. Their contents in the milling fractions varied between 0.35 and 1.38%, and above 0.6% ash content also increased with this parameter. Their L-arabinose-to-D-xylose ratios ranged between 0.65 and 0.39, with the lowest values found for the fractions with highest ash content, indicating that the ash-rich tissues contain more arabinoxylans that are less branched. (1)H NMR spectroscopy revealed that the decrease in L-arabinose-to-D-xylose ratio was accompanied by an increase in unsubstituted xylose residues and a decrease in disubstituted xylose residues, while the contents of monosubstituted xyloses were virtually constant.
Delcour
J A
JA
Laboratory of Food Chemistry and Center for Surface Chemistry and Catalysis, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, B-3001 Heverlee, Belgium. jan.delcour@agr.kuleuven.ac.be
Van Win
H
H
Grobet
P J
PJ
D007221:Industry; D014908:Triticum; D014990:Xylans / Q000737:chemistry*
D014990:Xylans