Moisture diffusivity in pears: Experimental determination and derivation of a mathematical prediction model.
2006
Guiné, Raquel
In the present work the dependence of moisture diffusivity on pear composition (in particular, water and sugar concentrations) was examined from the drying rate data measured experimentally. A model for predicting diffusivity that accounts for the effects of three variables (temperature, moisture content and sugar concentration) was then developed, and compared with the model presented by Zogzas and Maroulis (Drying Technology 1996;14:1543), which accounts only for the influence of temperature and moisture concentration. It was observed that the value for the activation energy predicted by the model that includes the influence of the sugar concentration is higher, showing that the amount of sugar present influences the diffusion of moisture through the pear. From the results obtained it was possible to conclude that at constant temperature the diffusivity is increased for higher water contents and lower sugar concentrations. Furthermore, it was possible to observe that higher temperatures have a much more pronounced influence on the diffusivity, compared with lower temperatures.
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