engleski

Study of the drying kinetics of "Granny Smith" apple in fluid bed dryer

The drying characteristics of "Granny Smith" apple were investigated using a bench-scale fluidised bed drier at different temperatures and using blanching in hot water as pre-treatment. Temperatures of fluidisation for non-treated and treated samples were 50, 60, 70 and 80 ºC and air flow velocity 3.5 m/s. The aim of the experiment was to get apples with approximately 9% water content, with good texture, rehydration capability and colour quality. The eff ect of temperatures and pre-treatment on the quality of dried apple samples was determined on the basis of colour and volume changes and reconstitution characteristics. The kinetic equations were estimated using logarithmic model. The results of the estimation have exhibited correspondence to experimental results. As a result of drying of non-treated apple at higher temperatures, drying time shortens, while rehydration properties improve. On the other hand, with the increase of the drying temperature, overall colour changes (ΔE) of non- treated samples increase. The best results, shorter drying time and better rehydration properties, were obtained when samples were pre- treated by blanching in hot water.

fluid bed dryer ; Granny Smith apple ; drying kinetics ; pre-treatment ; blanching ; rehydration

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