Rehydration and shrinkage behaviour of dried pineapple
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Data
2001-01-01
Autores
Nicoleti, J. F.
Telis-Romero, J.
Telis, VRN
Título da Revista
ISSN da Revista
Título de Volume
Editor
Isnt Tecnologico Veracruz
Resumo
The shrinking behavior, apparent densities and rehydration indexes of fresh and osmotically pre-treated pineapple slices during air-drying were obtained. The air drying velocity varied from 1.5 to 2.5 m/s and the air temperature from 40 to 70 degreesC. By means of automatic control, it was possible to obtain drying curves under conditions of constant product temperature. Volumetric shrinkage of fresh samples was temperature independent for drying at high air velocities but, at lower velocities, increased with decreasing drying temperature. Osmotically pre-treating the material resulted in reduced shrinkage, as well as drying with product temperature controlled, due to lower drying times needed that led to shorter high temperature exposition. Moisture dependence of apparent density was highly non-linear and could be fitted by an empirical model. Fresh sample rehydration indexes were higher than osmosed ones and increased with increasing temperature, except for pre-treated samples dried at 70 degreesC, probably due to superficial sugar caramelization, which reduced surface water permeability.
Descrição
Palavras-chave
volumetric shrinkage, apparent density, osmotic drying, air-drying
Como citar
Proceedings of the Second Inter-american Drying Conference. Veracruz 91860: Isnt Tecnologico Veracruz, p. 253-262, 2001.