Browsing by Author "Figueiredo, Margarida"
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- Modelling and simulation of pear dryingPublication . Guiné, Raquel; Rodrigues, Alírio; Figueiredo, MargaridaIn the present work a diffusion based model was adopted to represent the drying behaviour of pears in a continuous convective drier, taking into consideration the variation of the properties of the pears along drying. The program developed simulated a significant number of situations resultant from the variation of some of the oper- ating conditions. The temperatures tested were 30, 40 and 50 C, the air velocities were 0.5, 1.0 and 1.5 m/s, and the relative humidity of the drying air was 40%, 50% and 60%. From the situations analyzed, and considering the specifications required for the final product, it was concluded that the drying should be carried out at 40 C, with a drying air velocity of 1.5 m/s and containing 60% RH. 2007 Elsevier Inc. All rights reserved.
- Modelling and simulation of pear drying.Publication . Guiné, Raquel; Rodrigues, Alírio; Castro, José; Figueiredo, MargaridaIn the present work a diffusion based model was adopted to represent the drying behaviour of pears, in a continuous convective drier, taking into consideration the variation of the properties of the pears along drying. The program developed was simulated for a significant number of situations, varying the process variables. The temperatures tested were 30, 40 and 50 ºC, the air velocities were 0.5, 1.0 and 1.5 m/s, and the relative humidity of the drying air was 40, 50 and 60 %. From the cases analyzed and taking into account the specifications of the product that is to be obtained it was concluded that the drying should be carried out at 40 ºC, with the drying air at 1.5 m/s, and containing 60 % RH.
- Shrinkage characteristics and porosity of pears during drying.Publication . Guiné, Raquel; Ramos, António; Figueiredo, MargaridaThe high moisture content of pears (about 80 %) results in a high degree of shrinkage when drying takes place which strongly affects the fruit structure and quality. The aim of the present work was to study the shrinkage characteristics of pears during air drying, by evaluating their dimensions and volume along the drying process and by predicting particle and bulk densities as well as porosity as a function of material moisture content. The latter properties were estimated using a mathematical model available from literature whose parameters were either directly measured or determined by fitting some of the equations of the proposed model to the experimental data. The results predicted were subsequently validated by independent measurements.