Ultrasound-Assisted Hydration as an Approach to Improve Amylase Development During the Corn Malting Process

As a consequence of the increasing use of wheat and barley malt in food processes, there is a tendency to study alternative malted cereals. Corn malt is an emerging cereal that can be used as a source of clean-label enzymes for brewery, distilleries, and bakery applications. However, the conventional process of hydrating corn is an obstacle, as it usually takes longer than other cereals, making the development of enzymes slower. In this sense, ultrasound has shown a positive impact on water absorption kinetics. On the other hand, it has not yet been investigated how it affects amylase expression during germination. Thus, this work aimed to study the germination process of maize (Zea mays L.), focusing on changes in its amylase activity. The grains were subjected to ultrasound-assisted hydration (500, 700 and 1000 W) for 12 hours at 20 ºC to increase the moisture content from 9.97 to ~42%. Then, they were placed to germinate at 15 ºC in an incubator chamber for 88 hours, with water replacement every 16 hours. Every 8 hours, the samples were frozen and freeze-dried. The partially germinated corn was ground and had its alpha- and beta-amylase activities determined. It was observed that more significant changes began to appear for both enzymes after 16 hours of germination, with higher values for the samples treated with 700 and 1000 W, followed by 500 W and control. This trend continued until the end, with no significant differences for the two amylases