Drying of yam starch (Discorea ssp.) and glycerol filmogenic solutions at different temperatures

The objective of the present study was to obtain and model drying curves of filmogenic solutions at the temperatures of 25, 30, 35, 40 and 45 °C, consisting of different concentrations of starch and glycerol. The percentage of yam starch influenced the initial moisture content, while the critical moisture content varied as a function of the concentration of starch and temperature applied during drying of the filmogenic solutions. Glycerol concentration did not influence any of the parameters analyzed. Models for the two distinct phases (constant and decreasing drying periods) fit well for all drying temperatures and compositions, with average relative error values less than 10%. The interaction between starch content and temperature influenced the drying rate parameters during the constant period and the diffusion coefficients.

► The drying curves of the solutions obtained filmogenic two distinct periods. ► The first period was the longest linear due to high humidity of the material. ► In the period decreasing the higher the starch content lower the rate of drying. ► Higher values of starch and temperature reduces the cost of drying the film.