Acorn flour and sourdough: an innovative combination to improve gluten free bread characteristics

Nowadays, challenges in gluten free breads (GFB) are focused on improving the nutritional and health benefits. Acorn flour is an underexploited sustainable ingredient, naturally gluten free, with many nutritional and technological advantages. The aim of this study was to explore the interaction of acorn flour supplementation (up to 35%) to rice flour and sourdough process to obtain rice based GFB. Different levels of rice flour replacement with acorn flour (0%, 23% and 35%), and sourdough (20%) were tested in a basic GFB recipe, and technological, nutritional, and functional GFB characteristics evaluated. The combination of acorn flour and sourdough was responsible for acidifying dough and bread. Breads containing 35:65 acorn flour: rice flour led to harder breads with lower crumb luminosity and with reddish and brownish tones, besides improved structural features when adding sourdough. That combination of sourdough and acorn flour reduced the rate and the extent of starch hydrolysis, as well as increase the minerals content, total phenolic compounds and antioxidant activity. Therefore, the combination of acorn flour and sourdough process allows obtaining rice based GFB with better nutritional pattern.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Authors acknowledge the financial support of Grant RTI2018-095919-B-C21 funded by MCIN/AEI/1013039/501100011033, “ERDF A way of making Europe”, FCT-Portuguese Foundation for Science and Technology (PD/BD/135332/2017) under the Doctoral Program “Agricultural Production Chains – from fork to farm” (PD/00122/2012) and from the European Social Funds and the Regional Operational Program Norte 2020. This study was also supported by research units: CITAB (UIDB/04033/2020), Centro de Química de Vila Real (UIDB/00616/2020) and LEAF UIDB/04129/2020.Peer reviewe