Osmotic dehydration of pineapple (Ananas comosus) pieces in cubical shape described by diffusion models

To prolong the post-harvest life of agricultural products, one alternative is water removal. Pineapples, for instance, can be peeled, cut into pieces and dried. Conventional drying is an expensive operation due to the phase change of the water from liquid to vapor. Thus, a pretreatment such as osmotic dehydration is normally used. The main objective of this article is to describe the osmotic dehydration of pineapples cut in a cubical configuration, using the three-dimensional analytical solution of the diffusion equation and an algorithm optimization. Three models were proposed to describe the experiments with two concentrations of the solution of water and sucrose: 40 and 70 °Brix. One model that used several terms of the series that represents the analytical solution with boundary condition of the third kind well described the kinetics of water and solid migration, and enabled to predict the mass distributions at any given time.