Effect of bread-making process on the quality of acorn flour-enriched bread

Acorn flour has been recently proposed as an innovative and sustainable ingredient in bread production with potential nutritional and health benefits. This work aims to evaluate the inclusion of acorn flour in bread and to optimize acorn bread production process by optimizing acorn flour and dough hydration levels as well as production method (direct, sourdough, gel, and pre-hydration methods). The optimized breads were characterized in terms of specific volume, texture, bioactive compounds, acrylamide, and volatile organic compounds. The results show that increasing acorn flour levels (0-50%) in wheat sourdough bread progressively reduced loaf volume and hardened crumb texture. These undesired effects were significantly minimized by modulating dough hydration level and pre-hydrating acorn flour during dough preparation, allowing for obtaining bread with acceptable specific volume and texture up to 40% acorn flour inclusion. Acorn flour inclusion and sourdough fermentation significantly increased total polyphenol content and antioxidant activity, decreased acrylamide levels and improved aroma complexity, compared to the wheat control. This study provides a systematic investigation to identify the best production process to obtain acorn-enriched wheat sourdough bread, with an insight into physico-chemical profiles of the optimized products, offering an important reference for future studies on sustainable food development.