Tecno-Nutritional Improvement of Gluten-Free Breads Using Spontaneous Sourdough of Quinoa and Buckwheat Flours

The aim of this study was to evaluate the effect of spontaneous sourdoughs on the quality of gluten-free breads formulated with quinoa (Q) and buckwheat (BW) flours, in order to improve their nutritional, technological, and sensory attributes. The microbiota of the sourdoughs was dominated by Pediococcus pentosaceus and P. acidilactici. Total polyphenols, antioxidant capacity, phytic acid, and free amino acids were determined in sourdoughs (before and after fermentation), and breads. Breads were prepared with three levels of sourdough, 10%, 15%, and 20%. Bread specific volume, crumb firmness, staling rate, crumb structure, and consumer acceptability were evaluated. Sourdoughs showed higher phenolic compound contents compared to the unfermented control, and breads with sourdough contained on average 67% more phenolics than control breads. Antioxidant activity also increased, particularly in BW sourdough samples. Phytic acid decreased in both sourdoughs and breads, while free amino acids increased. Breads with Q and BW sourdoughs exhibited 40% and 25% higher specific volume, respectively, than the control, along with lower firmness and slower staling. BW sourdough breads reached the highest overall consumer acceptance. Incorporation of Q and BW spontaneous sourdoughs, especially at 20% substitution, significantly improved the nutritional, technological, and sensory quality of gluten-free breads.