Innovation in Cassava Bagasse Valorization: Efficiency of Convective Drying Enhanced with Ultrasound and Pulsed Electric Fields

Abstract

This research proposes an efficient alternative for dehydrating cassava bagasse to address the inherent challenges in the handling, transportation, storage, and preservation of this agro–industrial residue generated in cassava starch production plants. This residue is characterized by high moisture retention, considerable volume, and hydrophilic nature, complicating conventional drying methods. This study evaluates the impact of emerging ultrasound (US) and pulsed electric field (PEF) technologies prior to convective drying to enhance the dehydration efficiency of cassava bagasse, aiming at its valorization and contributing to the sustainability of the cassava starch industry. The findings reveal that pretreatment with ultrasound (US) and pulsed electric fields (PEF) significantly reduces the drying time of cassava bagasse compared to convective drying alone. With probe ultrasound at 26 kHz for 30 min, the drying time is reduced by 72% (3.83 h vs. 14.0 h); with bath ultrasound at 37 kHz for 30 min, it is reduced by 56.0% (6.16 h vs. 14.0 h); and with PEF at 7.5 kV/cm for 30 min, it is reduced by 52.4% (6.66 h vs. 14.0 h). These emerging technologies increased the effective diffusivity and modified the molecular structure of the bagasse, thereby improving mass transfer and drying process efficiency. These results are particularly useful for developing more efficient and sustainable strategies for drying agricultural by-products, with direct implications for the post-industrial treatment of agro–industrial residues with high water content.