Drying Kinetic and Bioactive Compounds of Okara Dried in Microwave-Assisted Rotating-Pulsed Fluidized Bed Dryer

This manuscript studied the effectiveness of microwave-assisted rotating-pulsed fluidized bed to dry okara and its effect on bioactive compounds. The microwave (MW) power (100-400 W) and application time (throughout the drying process and only the first 10 min of drying) were evaluated. The MW application accelerated the moisture losses of okara and the equilibrium moisture content was achieved earlier. Moreover, MW was effective in partially inactivating trypsin inhibitors present in okara due to the higher temperature inside the drying chamber. Such higher temperatures (> 75 degrees C) resulted in higher isoflavone losses without affecting the interconversion of isoflavones forms. We successfully applied a microwave-assisted rotating-pulsed fluidized bed to dry okara with a significantly high drying rate. Nevertheless, more studies are required to adjust the process parameters aiming to preserve isoflavone and to favor the interconversion of conjugated isoflavones to aglycones that present high bioavailability.

Automated summary

This study investigated the effectiveness of microwave-assisted rotating-pulsed fluidized bed for drying okara and its impact on bioactive compounds. The results showed that microwave radiation can accelerate the moisture loss in okara and achieve equilibrium moisture content earlier. In addition, microwave radiation was able to partially inactivate trypsin inhibitors in okara due to the higher temperatures inside the drying chamber. However, the higher temperatures also led to increased losses of isoflavones, necessitating further research to optimize the process parameters for preserving isoflavones and promoting their interconversion.