Effect of modified quinoa flour addition on quality attributes of gluten-free rice bread

To improve the rice-based bread (control) quality, the effects of partial substitution of rice flour with modified quinoa flour (10%-30%) on technological and sensorial bread attributes were investigated. An online survey revealed consumer interest in the proposed bread. Protein and fiber contents in breads exceeded the control values up to 22% and 125%, respectively. All of breads overcame control specific volume (1.46 ± 0.05 ml/g) by 6%-10%. Due to the quinoa fiber, breads presented a softer cell structure than control with greater cell area fraction (28.9%-37%) and cell density (52-69 cell/cm²). With increasing percentage of quinoa, color difference (Δ<i>E</i>) increased linearly (9-22.8), lightness (<i>L</i>*) decreased (73.3-62.8) and <i>a</i>* values increased denoting a higher proportion of red in the crumb. Breads with 10% and 25% quinoa had better texture, they obtained more positive evaluations than the control for taste (70%-86% "vs" 66%), odor (63%-75% "vs" 66%), color (74%-83% "vs" 78%) and texture (69%-70% "vs" 44%). The close relationship between sensory and instrumental measurements was evidenced by correlation analysis. Quinoa addition enhanced the nutritional and sensorial bread profiles as well as affected its technological quality, providing a distinctive crumb color and acceptable bread volume and crumb cell structure.