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Advisor(s)
Abstract(s)
In the present work a convective drier was used to dehydrate apple slices up to a moisture
content of less than 2 % (wet basis), so as to obtain a crunchy apple snack. Two commercial
varieties were tested, namely Golden and Smith. The drier was operated at different
temperatures, 30, 40 50 and 60 ºC, and the moisture content of the product was calculated
based on the mass, which was registered by means of a data logger, throughout the whole
trial. The kinetic data was then treated and fitted to different thin layer models frequently cited
in literature, which were: Page, Henderson and Pabis, Logarithmic and Vega-Lemus. Others
were also tested, but convergence was not achieved. For the fitting software SigmaPlot V8.0
(SPSS, Inc.) was used, and to evaluate the quality of the estimations the correlation
coefficient (R) and the standard error of the estimate (SEE) were determined
From the models tested it was possible to see that the Vega-Lemus was the worst to
describe the drying kinetic in the present case, on the other hand, the best model was the
Page. Also the Fick’s equation for diffusion was used to estimate the diffusivities at different
temperatures, and from those to estimate the activation energy for moisture diffusion, which
was found to be 35 kJ/mol for the drying of apples from Golden variety and 33 kJ/mol for the
Smith variety.
Description
Keywords
apple drying kinetics thin layer model
Citation
Cruz AC, Guiné RPF, Gonçalves JC, Correia AC. (2012) Study of the drying kinetics for apples in a convective drier. Proceedings (Electronic) da International Conference of Agricultural Engineering CIGR-AgEng2012, 6 pp.