Air-drying characteristics of plantain (Musa AAB)

The drying behaviour; shrinkage and moisture distribution within cylindrical pieces of plantain, of varying thickness, and with different air temperatures, were studied in an experimental hot-air drier By means of response surface methodology the influence of air temperature and thickness of the pieces on the drying rates was established. Air temperature had the greatest influence on drying behaviour The activation energy for air-drying of plantain was estimated as 38.81 kJ (g.mol)(-1). Shrinkage during drying was followed by changes in volume and dimensions of the pieces. Change in volume could be well described by a core drying model, while change in dimensions was related linearly with moisture content. A simulation, based on Fick's diffusion equation, was used to predict the distribution of moisture within the plantain pieces during drying. The predicted values related well to those obtained experimentally at moisture contents less than 1.20 kg (kg d.s.)(-1). This type of model could be used to determine local moisture contents rather than average moisture contents in food pieces, thus predicting more accurately the susceptibility of the food to spoilage. (C) 1998 Elsevier Science Limited. All rights reserved.