The influence of ethanol on the convective drying of unripe, ripe, and overripe bananas

Abstract

In this work, the influence of ethanol on convective drying of unripe, ripe, and overripe bananas was investigated. The experiments were performed at 60°C with air velocity at 0.84 m s−1 under the following conditions: normal atmosphere, atmosphere modified with ethanol (0.5% v/v), and ethanol brushed on the surface of the samples. Among the ripeness degree, the unripe was correlated with higher diffusivity, followed by the ripe and the overripe conditions, in this order. With respect to the treatments, the higher diffusivity was obtained with the surface use of ethanol, followed by the modified atmosphere and the normal atmosphere, in this order. Shrinkage and color were also investigated. The longitudinal shrinkage was always greater than the radial shrinkage and there was no influence of ethanol treatment on shrinkage. It was observed that there was higher total color difference (ΔE) for unripe and overripe bananas at normal atmosphere and higher ratio of luminosity ( ) when ethanol was used.