Modeling and Optimization of Sheanut (Vitellaria Paradoxa) Kernel Drying in a Tray Dryer Using the Response Surface Approach in Comparison With Other Thinlayer Drying Models

Purpose The study aimed to investigate the drying characteristics of shea nut kernels (Vitellaria paradoxa) at different temperatures and to optimize the drying process for improved economic viability and sustainability of shea nut production. Methods Drying experiments were conducted at temperatures of 50, 60, 70, and 80°C using a Cole model dryer. Data obtained were tested against 14 commonly applied drying models. The drying process was modeled and optimized using a Response Surface Methodology (RSM) approach to determine the best conditions. Results Higher temperatures significantly reduced drying time and moisture content (p < 0.05), with drying occurring exclusively in the falling rate phase. The models generated via RSM best described the drying behavior, with the highest R² values at all studied temperatures; the Modified Hii model was most suitable at 50 and 60°C, while the Midilli and Kucuk model fit best at 70 and 80°C. Interaction between temperature and time affected moisture reduction and drying rate in a non-linear manner. The optimal conditions identified were a moisture content of 0.1766, moisture ratio of 0.23454, and drying rate of 3.955×10⁻⁴ at 65°C for 350 minutes. Conclusion The findings enhance the understanding of shea nut drying behavior and support the optimization of drying parameters, contributing to the economic viability and sustainability of shea nut processing. Future research should focus on energy efficiency of drying techniques and assess the nutritional quality and shelf life of dried shea nut kernels.