Drying kinetics and quality attributes of low-fat banana slices dried at high temperature

High temperature drying may give rise to hydrostatic pressure gradients of moisture inside the dried sample and subsequently leads to large voids, resulting in crispy product. In this study, the drying characteristics as well as various quality attributes, namely, colors, shrinkage and textural property of banana slices dried at high temperatures (110–140 °C) in a tray dryer were explored. Banana slices were dried from the initial moisture content of 250–300% dry basis to the required final moisture content of 4% dry basis. The analysis of the drying rate evolution revealed three drying regimes, i.e., warming-up and two falling rate periods. The effective diffusion coefficient of banana was found to increase with a decrease of the moisture content until a certain moisture content after which the diffusivity decreased. In terms of quality, the large pore assembly was produced at higher temperature of 120 °C as observed from SEM micrographs. The drying temperature also significantly affected the colors, shrinkage and texture of bananas.