Use of diffusive and empirical models to predict drying rate of acerola seeds (Malpighia sp.)

The thin layer drying process of acerola seeds was analyzed using a flat plate geometry diffusion model, Page's model, and a two-part model proposed based on the diffusion equation. These models were fitted to experimental drying kinetics data of acerola seeds for an air flow speed of 1.5 m/s, at temperatures of 40, 50, 60 and 70°C, using non-linear regression by Levenberg-Marquardt method. The diffusion model was used to determine the diffusion coefficients and activation energy. The predicted and experimental results were compared using the determination coefficient (R2) and mean square error (MSE) of the estimates as criteria. The results showed that the diffusion model is not suitable for predicting the drying rate of acerola seeds, while Page’s equation and the two-part proposed model can be safely used to predict the drying rates.