Water-soluble pentosans form very viscous solutions because of their much higher
intrinsic viscosity compared to soluble proteins. A unique property of water-soluble pentosans
is their ability to form gels in the presence of oxidizing agents. This process of oxidative
gelation was monitored by Kundig et al. (1961b), who noted the disappearance of a peak at
320 nm in the UV spectrum of pentosans following the addition of oxidizing agents. The loss
of this peak was attributed to involvement of ferulic acid in the gelation process. A
mechanism was subsequently proposed by Neukom and Markwalder (1978) in which a dimer
of ferulic acid formed a cross-linked between pentosans (Fig.5). Two active centers in ferulic
acid were thought to account for the increase in viscosity via cross-linking. One was the
aromatic nucleus while the other was the activated double bond. Only the activated double
bond in ferulic acid was involved in the gelation process. The formation of such cross-links
through covalent binding of protein and polysaccharide chains could affect the rheology of
the dough. Kim and D′Appolonia (1977) suggested that pentosans decreased the rate of bread
staling by decreasing the amount of starch components available for crystallization