Drying kinetics of enriched pineapple residue

Brazil is the largest producer of pineapple (Ananas comosus L.) in South America and one of the largest in the world. The fruit is the marketable part of the plant, while the rest formed by stem, leaves, peel, crowns and shafts is considered as agricultural residue and is not properly used, resulting in economic loss. The aim of this study was to characterize and to evaluate the drying kinetics of enriched pineapple residue (peel) using Saccharomyces cerevisiae yeast in static bed in fine layer, using of experimental factorial planning. The temperature (40 to 60 degrees C) and the wind speed (0.8 to 1.3 m s(-1)) were the process variables. The characterized enriched residue exhibited a high dry matter content (90.27%) and a high protein content (20.21%) in relation to fresh residue (7.61%). The drying kinetics occurred in falling rate period. The Page, Henderson & Lewis and Pabis models adjusted satisfactorily to experimental data, being the Page model slightly superior to the others. Influence of the temperature variable was verified only for the moisture response variable, while no significant influence of the wind speed of drying was observed.