Characteristics of Convective Drying of White-Skinned Sweet Potato Spheres (Ipomoea batatas [L.] Lam)

Abstract

White-skinned sweet potatoes are a highly sought-after food product in Burkina Faso. However, there are times when this product is very scarce or even unavailable in the country. It is therefore necessary to find a way to preserve it. Despite the drying method already used for preservation, we encounter dried products of poor quality that do not last long. It is in this context that our study aims to understand and optimise the best method for preserving white-skinned sweet potatoes through drying. To carry out this study, we first cut them into spherical shapes with diameters of 2 cm and 3 cm, which we then placed in an oven at fixed temperatures of 80°C, 70°C, 60°C, and 50°C. The behaviour of each size was studied for 6, 8, 10 and 12 hours respectively at different temperatures. The results showed that for a residual water content of approximately 5%, the drying time for potatoes with a diameter of 2 cm was 500, 800, 1040 and 1900 minutes, while potatoes with a diameter of 3 cm took 780, 890, 940 and 2400 minutes respectively, depending on the temperatures studied. These results allowed us to conclude that the drying time is proportional to the shape of the white-skinned sweet potato. Added to this is the evolution of the water velocity of the two different diameters. The results show that the 2 cm potato dries faster than the 3 cm potato.