Unlocking the potential of solar thermal technology: Pretreatment-driven enhancement in cassava flour production

This study explored the integration of pretreatment techniques into solar drying technology to enhance drying efficiency and product quality of cassava flour. Fresh cassava tubers were sliced and subjected to two pretreatment methods: chemical-thermal treatment (DB1; citric acid and sodium metabisulfite with blanching) and prolonged water soaking (S3D). Utilizing a solar dryer designed for optimal solar energy capture, thin-layer drying experiments revealed distinct kinetic behaviors, best modeled by the Wang and Singh equation for DB1 and the Page model for S3D samples. DB1 pretreatment significantly improved drying performance, demonstrating more efficient solar energy utilization (increasing moisture diffusivity by 43 % and reducing activation energy from 33.23 to 30.70 kJ/mol, equivalent to a 7.6 % decrease). Physicochemical analyses showed that hydrogen cyanide content was reduced by 61 % (DB1) to 96 % (S3D) and the whiteness index improved from 89.90 (control) to 91.40 (pretreated samples). Sensory evaluation enhanced texture, appearance, and overall acceptability for DB1-treated flour. The findings highlight the viability of combining targeted pretreatment methods with solar drying technology to sustainably produce high-quality cassava flour suitable for rural and energy-limited settings.