Kinetic study of dehydration and desorption isotherms of red alga Gracilaria

The aim of this research was to study the desorption isotherms at three temperatures (5, 20 and 40 °C), and to model the drying kinetics at four temperatures (40, 50, 60 and 70 °C) of the red alga Gracilaria. Modeling of sorption isotherms was carried out following the BET, Caurie, Halsey and Oswin equations. All the equations showed generally a good fit; however, the Halsey equation was considered the best to predict the experimental data. The Modified Page and Wang–Singh mathematical models were applied in the study and modeling of drying of this alga, as well as two new models proposed in the present research. Modified Page and the proposed Model no 2 obtained the best fits for each drying curve based on the statistical tests employed (r2, SSE, RMSE and χ2). In consequence, both models are excellent tools for estimating the drying time of this product.