Modulation of in vitro digestibility and physical characteristics of protein enriched gluten free breads by defining hydration

The association of diabetes on celiac disease together with the high glycemic index of gluten-free breads makes necessary the pursuit of a solution to reduce this glycemic response. Protein enrichment and changes on hydration level may be tools to get it. Thus, the aim of this study was to analyze the effect of two proteins (pea and egg white) on the digestibility and physical characteristics of gluten-free breads, with either the same hydration or specific volume. Protein enriched breads were made blending starch and proteins (70:30). Breads prepared at constant hydration presented lower specific volume and weight loss during baking, and higher hardness than control. However, when the specific volume was matched, the breads with egg white protein presented lower weight loss and higher hardness, while the ones with pea protein were the less hard. Protein enriched breads showed higher SDS and lower RDS values than control with constant hydration, but lower SDS values and glucose release with constant specific volume. Therefore, the bread volume influenced not only the physical properties but also the bread digestibility.Financial support of the Spanish Ministry of Science, Innovation and Universities (AGL2014-52928-C2, RTI2018-095919-B-C21), the European Regional Development Fund (FEDER) and Generalitat Valenciana (Project Prometeo 2017/189). M. Sahagún and Y. Benavent-Gil would like to thank predoctoral fellowships from of University of Valladolid and Ministry of Science, Innovation and Universities, respectively.Peer reviewe