Energy consumption and thermal properties of drying banana (musa ssp) under varied relative humidity

Abstract

The drying of banana slices was investigated under different relative humidity (RH) in a convective hot-air dryer. The experiments were conducted using 10, 20, 30 and 40% RH, 75oC and 2.0 m/s air velocity drying conditions. Drying kinetics, energy consumption and thermal properties were investigated. Eight mathematical models describing thin layer drying were employed and results were compared to their goodness of fit in terms of coefficient of correlation (R2), the root mean square error (RMSE) and the reduced chi square (χ2). The Midilli–Kucuk model could satisfactorily describe RH-convective drying of banana slices with R2, RMSE and χ2 in the ranges of 0.99947-0.99986, 0.00002-0.00008, and 0.0142-0.01618 respectively. For energy consumption, RH condition increased the energy consumption such that at every 10% increase in RH, a range of 17.9-41.0% increase in energy consumption was observed. In the case of thermal properties, endothermic peak revealed precise composition, fine particle size, and dispersion in a matrix of banana slices thus altering the transition in solid state. In effect, RH drying present new drying concept with prospecting thermodynamics absorbing properties. However, energy consumption issue needs to be addressed in further research.