Cell wall composition of 1B/1R translocation wheat grains

The cell wall composition and total dietary fibre content of 12 different winter wheat cultivars both without and with 1B/1R gene were analysed. Translocation wheat (with 1B/1R gene) had higher contents of extractable xylose and unextractable mannose residues than standard wheat (without 1B/1R gene). Three sieved flours of standard wheat, translocation wheat and rye respectively were used for further detailed studies. Water-extractable arabinoxylan was isolated and fractionated on a DEAE-cellulose column. The water-eluted fraction of translocation wheat had a higher proportion of monosubstituted xylose residues than the same fraction of standard wheat, which is a typical feature of rye arabinoxylan. Molecular weight determination showed that rye water-eluted arabinoxylans were larger than those of wheat. The molecular weight of translocation wheat arabinoxylan was lower than that of standard wheat and had a high polydispersity. Xylanase-resistant arabinoxylan was extracted from all three flours, and NMR studies showed that wheat xylanase-resistant arabinoxylan had a lower amount of monosubstituted xylose residues, while the rye fraction was rich in consecutive disubstituted xylose residues. Translocation wheat xylanase-resistant arabinoxylan resembled that of standard wheat.