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vol. 11, nr. 1 (2008)
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Rehydration of carrot dried using various methods
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Bogdan Stępień
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Agricultural Engineering Institute, Wroclaw University of Environmental and Life Sciences, ul. Chełmońskiego 37/41, 51-630 Wrocław |
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vol. 11 (2008), nr. 1,
pp. 239-251
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abstract:
Raw carrot, blanched and osmotically dehydrated, was dried using three methods: convection, freeze-drying and vacuum-microwave drying. The rehydration was achieved by weighing carrot slices and inundating them with a fixed amount of water at 20ºC. Values of the gain in the mass of the sample, of the relative gain in the water mass, and changes in the relative contents of dry matter were calculated. After five hours of rehydration process only the freeze-dried carrot was characterized by a mass close to the equilibrium mass. At the same time of rehydration, 60% to 80% of the initial water mass infiltrate the carrot tissues. Blanching, and in particular osmotic dewatering, substantially reduce the water absorption rate. No essential impact of the drying method on the value of losses in the dry matter during carrot rehydration was found, for material not subjected to preliminary treatment before drying.
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keywords:
rehydration, drying methods, blanching, osmotic dehydration
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original in:
English
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