Effects of quinoa flour addition on composite gluten-free bread: a comprehensive study of microstructural, oscillatory rheology and baking properties of bread dough

Abstract

The goal of this research was to conduct a microstructural study of gluten-free bread dough by incorporating nutrient rich quinoa flour (QF). Three levels of QF (40%, 50% and 60%) were used to prepare dough composites by replacing the dry blend of rice and maize flour (at a 1 : 1 ratio) while maintaining a hydration level of 90%, based on a 100 g flour basis. Fundamental rheological experiments were performed to access the viscoelastic behaviour of dough. The results indicated that quinoa addition modified the dough behaviour, evidenced by an increment in levels of G′ and G″ from 4.629 Pa and 3.870 Pa to 4.880 Pa and 4.333 Pa, respectively, and early onset of gelatinisation revealed in the temperature sweep experiment (+7.8 °C) due to changes in starch–protein interactions with water. This study employed a power law model to evaluate its applicability to the rheological data of dough composites across various concentrations. DSC baked dough samples revealed a reduction in ΔH_G from 2.88 J g⁻¹ to 1.85 J g⁻¹ and ΔH_R from 5.21 J g⁻¹ to 2.62 J g⁻¹, which correlated well with XRD analysis as RC values increased from 23.28% to 34.68%. Furthermore, an increment in short-range orderliness (i.e. DO and DD values from 1.06 to 1.25 and 1.06 to 1.38, respectively) indicated establishment of a stable structure and well-organized structure. After breadmaking, specific volume and cell density improved significantly which further coincided with the sensory analysis results. To sum up, the composite dough that included 50% QF displayed optimal rheological characteristics and baking quality in any instance. The results of the present study would provide necessary guidance for further improvements in making breads using gluten-free multi grain flours.