Pentosans, a heterogeneous mixture of non-starch polysaccharides, account for a small fraction of wheat flour composition, but are known to affect the physical properties of gluten and doughs and thereby the baking performance of wheat flours. They are characterized by a high water-absorbing capacity and high viscosity, and, therefore, are expected to compete with starch for water. The properties of starch pastes and gels have been shown to be dependent on concentration, size and rigidity of starch granules, swelling degree and amount of amylose and amylopectin leached out during heating, amylose-amylopectin, granule-to-granule, amylose-granule and amylopectin-granule interactions. In addition, water is known to affect gelatinisation, the gelation mechanism and retrogradation of starch. The gelatinisation and retrogradation of starch is also affected by the presence of several hydrocolloids, including pentosans.14'13 The quality of baked products and starch-based ingredients can, thus, be affected by the level and properties of these polysaccharides. The present research assessed the role of wheat water-soluble pentosans on the rheological and thermal behaviour of starch dispersions during gelatinisation and after gel formation. Two different water levels were studied, considered as representative of intermediate and excess hydration, using both rheological and DSC measurements.
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