Hot-air ultrasound-assisted drying of green wheat and barley malts to enhance process kinetics, amylase activity and their application in bread formulation

Malting produces techno-functional cereal ingredients but it is considered a time-consuming process. The assistance of ultrasound (US) appears to enhance the drying step of the green malts. In this sense, partially germinated wheat and barley were convectively dried with and without US. The obtained malts were analyzed regarding amylolytic capacity and their performance as ingredient in bread formulations. Compared to oven drying, hot air convective US-assisted system decreased drying time by intensifying drying velocity up to 56 % and 129 %, respectively. Similarly, α- and β-amylase activities were intensified by up to 88 % and 10.5 %, respectively, when drying occurred with US. Breads formulated with US-dried malts resulted in better bread-making properties, mainly peak torque and setback values. Specific volume, crust color and pore distribution in real bread were also improved together with hardness of degassed crumb samples. Therefore, US can be used not only to intensify the conventional malting process but also to produce more efficient ingredients.