Drying of bananas using microwave and air ovens

Abstract

Drying tests for ripe and green banana ( M u m cv. Giant Cavendish AAA) slices and for a foam made from ripe banana puree were performed in a household microwave oven and in a laboratory forced draft warm air oven. Weight change of the banana slices as a function of time in both ovens, and temperature and relative humidity (RH) of air leaving the microwave oven were recorded. Drying rates were calculated and the data fitted to a variable diffusion model. Drying time in the microwave oven was seventeen to twenty times less than in the forced draft oven. The drying energy efficiency in the microwave oven was about 30%.

Air-drying of banana: Influence of experimental parameters, slab thickness, banana maturity and harvesting season

“…Commercially, banana is dried to less than 20 % final moisture content, (Bowrey et al 1980;Robinson 1980) or down to 14-15 % final moisture content (on dry basis) (Garcia 1988). This corresponded to 69.7% mass loss (20% final moisture content) or to 71.2 % mass loss (14 % final moisture content) in this work.…”

“…The removal of water in a foodstuff during drying occurs via two mechanisms: migration of water within the foodstuff and evaporation of moisture from the foodstuff into the air. The former is considered as the most common moisture migration during drying, and has been used to explain the drying kinetics of banana (Mowlah et al 1983;Garcia 1988;Sankat et al 1996).…”

“…Their results showed that the most intensive heat and mass transfer occur in the transition region, where capillary flow and vapour diffusion play an important role. A variable diffusion model was proposed by Garcia (1988). In this work, banana slices and foam were dried using microwave and air ovens.…”

“…Fick's law of diffusion has been used to describe the drying kinetics of fruit during the falling rate period. Modelling the drying of banana has been reported by several authors using Fick's law of diffusion (Mowlah et al 1983;Garcia 1988;Sankat et al 1996).…”

“…Most studies (Mowlah et al 1983;Garcia 1988;Mulet et al 1989) of dehydration of banana have focused on the validation of a particular model, under a limited range of drying conditions. The effect of temperature on the drying kinetics was of most interest in these studies.…”