Drying of Curcuma longa L. in different shapes

The process currently used by most agricultural producers for drying Curcuma longa L. consists in the exposure of the product to atmospheric conditions, on a plastic film on the ground, using solar radiation as energy source for drying, without the use of any kind of apparatus for protection against the weather or animals. Under these drying conditions, in an ambient with practically no temperature and moisture control, various problems can arise, such as an excessively long time to reach desired moisture content, with the concomitant growth of microorganisms harmful to health and high product deterioration. Prediction of drying time is also an information difficult to obtain for this process, because there is no control of drying conditions. The mean time necessary to dry the product can reach twenty five days, which is not industrially interesting. This paper presents Curcuma longa L. drying curves, resultant from experimental drying in a convection oven under different temperature, air velocity and type of cut conditions. It is possible to identify the influence of the peel, type of cut, temperature and air velocity on drying time, important parameters in the development of new drying equipments and processes.