Effect of ultrasonic treatment on soybean okara to be used as a gluten-free bread improver

The production of soybean protein isolates generates an insoluble residue called okara that is rich in proteins and dietary fibre. These macromolecules have functional properties that can be modified and improved by emerging technologies, such as high-intensity ultrasound. The objectives of this work were to analyse the ability of soybean okara (UOK) to act as a gluten-free bread improver and to evaluate the effect of a sonication process on this property (OKS). Both okaras were assayed at two percentages (2% and 3%) leading to a reinforcement of interactions in the matrix of batters, producing bread of better technological and sensorial quality. The addition of OKS 3%, improved specific volume (20%), reduced the hardness (30%) and increased the cohesiveness of the crumb and improved the air inclusion. These results demonstrated the efficiency of the sonication process to obtain a gluten-free bread improver from a bulky by-product of the soybean industry.