Physicochemical and functional aspects of composite wheat-roasted chickpea flours in relation to dough rheology, bread quality and staling phenomena

Abstract

Wheat flour was substituted by flour from roasted chickpeas at 10–20% (flour basis) and a multi-instrumental analytical approach was employed to explore the dough rheological behavior of the composite starch-proteins hydrated networks, the quality attributes of the resultant breads, as well as the staling process. Fortifications with roasted chickpea flour at 15 and 20% level significantly increased dough viscosity and elasticity as showed by oscillatory and creep-recovery rheological tests, implying higher dough resistance to flow and deformation that resulted in breads with significantly lower specific volumes and harder crumb than the control (bread without chickpea flour). Moreover, at 20% substitution level, the staling kinetics of composite breads, as monitored by texture profile analysis, indicated a greater extent of crumb hardening at the end of storage, whereas the level of retrograded amylopectin in the crumb as assessed by calorimetry (DSC) did not differ among samples. Nevertheless, for bread with 20% chickpea flour, FTIR spectroscopy revealed a large increase in protein β-sheets and a further increment of such conformational change in the stored crumb, suggesting dehydration of gluten and its involvement in the staling process. Instead, formulations with 10% roasted chickpea flour did not exhibit any major influence on dough rheological behavior, as well as on textural attributes and bread staling. Furthermore, at 10% substitution of wheat flour by roasted chickpea flour, there was complete masking of the “grass-like” and reduced “beany" and "earthy” off-flavor notes in breads, as assessed by a trained panel, pointing to a product with high overall acceptability.