Structural changes during air drying of fruits and vegetables

This work aims at reviewing structural changes occurring in convective air drying of fruits and vegetables. These include changes in physical properties, such as volume, porosity and bulk and particle density, which directly affect textural attributes of the products. Models relating with water content physical properties are also summarised. At microscopic level, the phenomena observed by previous authors is described, focusing on shrinkage. In particular, a new approach on modelling kinetics of microstructural modifications is presented. Although the air drying process is relatively well studied, there is a lack of research concerning changes in structural Properties. Modelling mass transfer during drying frequently does not include those effects and, there has not been established a standard methodology for predictive purposes. Correlating microstructure, texture measurements and sensory analysis would be an attractive area to be exploited for drying processes of fruits and vegetables. Although this is a wide working field, much is still to be done.