Impact of the combination of sourdough fermentation and hop extract addition on baking properties, antioxidant capacity and phenolics bioaccessibility of rice bran-enhanced bread

The effect of hop sourdough fermentation combined with rice bran (RB) addition was investigated for improving technological, bioactive and sensory properties of wheat bread by optimizing the quantities of RB, yeast, sourdough and hop extract contents based on response surface methodology. The bread produced according to the optimized formula was compared with control bread, sourdough or RB-enhanced bread with regard to quality attributes, bioaccessible phenolics and antioxidant activity. Sourdough fermentation combined with RB flour increased volume of loaves and consumer acceptance with no significant variations in crumb moisture content and crumb firmness during storage. RB darkened crumb while no effects on colour were observed for sourdough bread. Sourdough technology allowed increasing phenolic content of RB bread with no significant differences in its antioxidant activity. The bioaccessible ferulic and sinapic acids, the main phenolics released in vitro digestion of optimized bread were lower compared to those of control bread.