Mathematical Modelling of Thin-Layer Drying of Pale-Fleshed, White-Skinned Spherical Sweet Potato (Ipomoea Batatas)

Abstract

In this study, the mathematical modelling of hot air convective drying of (Ipomoea batatas L.) pale-fleshed, white-skinned spherical sweet potato (a variety newly introduced and grown in Burkina Faso), were investigated at 50°C, 60°C, 70°C and 80°C air temperatures. Sweet potato samples were prepared at 2 and 3 cm diameter and dried using a convective oven dryer. For this purpose, forty-three (43) mathematical models were used to estimate the drying coefficients following nonlinear regression method to find the best fit of the moisture ratio models obtained from experimental database on the following parameters: coefficient of determination (R<sup>2</sup>), Sum of Squared Errors (SSE), and Root Mean Square Error (RMSE). Drying data analysed were obtained in the period of falling drying rate. The modelling results obtained showed that almost all models had R<sup>2</sup> greater than 0.90 which shows their competitive fit to the drying data of sweet potato spherical samples. Based on statistical parameters results obtained, sweet potato spherical samples can be best dried at 70°C with 3 cm diameters. The Haghi and Angiz-I model was the best fit for predicting the moisture ratio of sweet potato spherical samples dried in hot-air oven dryer based on average values from statistical analysis (R<sup>2</sup> =0.999587, RMSE =0.004375 and SSE= 0.002175).