Cinética da secagem e difusão efetiva das sementes de melancia

Abstract

In Brazil the watermelon production (Citrullus lanatus) extends throughout the year, being that the species most produced have a significant number of seeds. As well as the fruit, the watermelon seeds contain essential nutrients to the human, highlighting the lycopene presence, substance on which interrupts the appearance of cancerous cells. However, the watermelon seed has low water content, being that one of the processes of post harvest that keeps the quality of the product to the storage it is the drying. The seeds presented water content of approcimately 48%. Furthermore, in order to better process performance, the study of drying kinetics is necessary for the development of the mathematical modeling. As a result, with this work aimed to adjust nine mathematical modeling, in order to select the one that best represented the behavior of the drying of watermelon seeds. In addition to determining the diffusion coefficient and the activation energy at different temperatures. Seeds were dried in an experimental dryer at temperatures of 60, 55, 50, 45 and 40 °C, with a steady stream of 0,8 m/s. Four replications were made at each temperature. For the adjustments of the models made linear regress analysis, by Gauss-Newton method. According to the data, concludingfor the temperatures of 60, 55 and 50 °C the model that adjusted the drying was the one of Page. And for the 50, 45 and 40 °C in temperatures of the Diffusion Approximation model. Andrying rate influenced by water rate. The diffusion coefficients with a magnitude of 7.69684x10-10 and 1.27585x10-09 for the range of 40 to 60 °C. Activation energy was 12.2641 kJ.mol-1.