Impact of Bean-Flour Sourdough on Technological Quality, Colour and Antioxidant Properties of Wheat-Based Bread

Introduction: Sourdough fermentation is a useful biotechnological approach for improving the technological and functional potential of bakery products enriched with legume ingredients. Bean flour may provide additional functionality, but its influence on bread quality depends on fermentation behaviour and formulation. This study investigated the effect of bean-flour sourdough and wheat-bean flour formulations on wheat-based bread properties.

Methods: Bean flour sourdoughs were incorporated into wheat-based formulations. Doughs were fermented at 35 °C for 2 h and baked at 220 °C for 15 min. Breads were assessed for pH, baking loss, water activity, colour, aroma profile, total phenolics, reducing sugars and antioxidant properties.

Results and Discussion: The soaked-bean sourdough showed stronger acidification than the boiled-bean sourdough, with pH values of 4.59 and 5.28, respectively. Baking loss ranged from 12.36% in the control bread to 18.80% in bread prepared with the wheat–boiled bean flour blend and boiled-bean sourdough, while water activity remained high and stable (0.977-0.984). Bean-flour formulation and sourdough addition affected bread colour, especially crust lightness, which decreased to 35.51 and 34.48 in breads with wheat-boiled bean and wheat-soaked bean flour blends, respectively, compared with 50.53 in the control. Electronic-nose analysis showed that bean-flour formulation influenced the volatile profile of the breads, with the clearest differences related to sensor responses associated with nitrogen-containing compounds and sulfur- and terpene-related volatiles. Antioxidant properties were modified; in the crumb of bread prepared with the wheat-boiled bean flour blend and boiled-bean sourdough, total phenolic content reached 0.922 mg GAE/g DM in water extract and 1.387 mg GAE/g DM in ethanol extract.

Conclusions: Bean-flour sourdoughs and wheat–bean flour formulations influenced baking performance, colour, aroma profile and antioxidant properties, supporting their potential for functional wheat-based bread.