Effect of soluble dietary fibre from barley on the rheology, water mobility and baking quality of wheat flour dough

Abstract

Incorporation of dietary fibre in a bread recipe is a technological challenge. Therefore, the aim was evaluating the impact of substitution of wheat flour with extracted soluble dietary fibre from barley (BDF) at two levels (4.0% and 8.0%) on dough and bread characteristics. The percent water absorption and mixograph peak mixing time increased for both BDF substitution levels, while T22 relaxation time reduced significantly. In addition, 4.0 and 8.0% BDF substitution levels resulted in a 20.6% and 33.4% reduction in freezable water (FW) content, respectively, and increased G′ and G″ values. In creep tests, BDF dough showed reduced creep compliance values and recoverable strain percentages. BDF limits the water availability in dough for the other biopolymers as reflected in more β-sheet structures, reduced water mobility and lower FW content. The reduction in water availability results in impaired development of an elastic gluten network and an increased resistance to deformation, eventually translating in higher crumb hardness and lower loaf volume. These insights can serve as basis for targeted interventions to recipes and processing to counteract the adverse effects of BDF on bread properties. This study also revealed that 4.0% BDF substitution of wheat flour does not adversely affect bread quality.