Soybean by-products and modified cassava starch for improving alveolar structure and quality characteristics of gluten-free bread

There is a global trend towards assuring more sustainable application of ingredients in food development, with emphasis in the nutrients recovering from agro-industrial by-products. Soybean extruded–expelled meal (SF) was explored to take an advantage from its nutrients; and its behaviour with pregelatinised cassava starch (PGS) and hydration levels (WC) as a contribution to technological improvement in gluten-free (GF) bread-making. The aim of this work was to study the effects of different levels of SF, PGS and WC on alveolar structure and final quality characteristics of GF bread formulation. A Box–Behnken experimental design and surface response methodology were applied. The final quality of GF breads was significantly affected by the addition of SF, PGS and WC, being the SF and WC the components with major impact. Lower levels of PGS and SF showed higher specific loaf volume with a softer crumb, faster recuperation of resilience and springiness, and less susceptibility to being disintegrated. The colour intensity and the uniformity of the alveolar crumb structure were enhanced by SF addition. Optimisation carried out to improve the physical and textural characteristics of bread, rendered a formulation with PGS 15.0 g × 100 g −1 , SF 6.0 g × 100 g −1 and WC 160 g × 100 g −1 . A size portion of GF bread (50 g) would increase 1.4- and 3.7-fold the protein and fibre intake, respectively. The addition SF and PGS with the adequate hydration level is promising for producing GF bread with an improved technological and nutritional profile, and could be useful to add value to an industrial by-product and reduce manufacturing cost.