Water-soluble arabinoxylans from flours of 10 cultivars belonging to f
ive classes of Canadian wheat were isolated and purified. Fractionatio
n of arabinoxylans by a graded (NH4)2SO4 technique gave three fraction
s: F65, F75, and F100. The numbers refer to the saturation level of th
e salt at which precipitation occurred. The yield of F65 was 53.3-85.9
% of the total material recovered; F75 accounted for 10.2-35.7%; and F
100 was only 3.9-11.0%, F65 showed the highest viscosity (3.15-5.24 dl
/g). Viscosity decreased in F75 (2.23-3.60 dl/g) and F100 (0.88-1.21 d
l/g). Ferulic acid was confined mostly to F65. The xylose-to-arabinose
ratio was the highest for F65 (2.23-1.53) and much lower for F75 and
F100 (1.22-1.05 and 1.18-1.03, respectively). F65 was a high molecular
mass arabinoxylan fraction with the highest amount of xyloses carryin
g only one arabinose side chain residue (at C-2 or C-3), but it had th
e lowest content of xylose residues substituted with arabinoses at bot
h C-2 and C-3. F75 and F100, with decreasing molecular mass of arabino
xylan fractions, had a decreased amount of singly substituted xyloses
but an increased amount of doubly branched xyloses. The occurrence of
unsubstituted Xylp residues was much higher in the high molecular mass
arabinoxylan fractions. The short Ara side chains were more commonly
encountered in low molecular mass arabinoxylan fractions.