Galacturonic acid, galactose and arabinose were also found in
significant amounts in the pseudocereal SDF fractions and are
indicative of the presence of pectic polysaccharides. Homogalacturonans,
indicated by the significant amounts of galacturonic acid
and lack of rhamnosyl residues, are the important constituent of
the pectic polysaccharides. The low xylose content and high
amount of galacturonic acid found in QUSDF suggests that this fibre
sample is mainly composed of pectic polysaccharides, namely,
homogalacturonan and arabinan. Based on the sum of terminal,
(1?3)-, (1?3,5)- and (1?5)-linked arabinose plus the mol.%
value for galacturonic acid, pectic polysaccharides were estimated
to constitute 55% QUSDF and 34% AMSDF of the SDF fractions. As in
the case of estimated xyloglucan content, the exact amount of pectic
polysaccharides cannot be determined here. Although not as
significant as the other monosaccharides, mannose was found in
the SDF fractions in considerable amounts. Galactomannan content
was measured in pseudocereal SDF fractions and both contained
low amounts (0.5 g/100 g QUSDF; 0.3 g/100 g AMSDF).