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vol. 4, nr. 3 (2004)
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Dependence of qualitative factors of lyophilisate, drying time and energy consum-ption on its humidity
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Tadeusz Lis, Helena Lis, Ewa Kłoczek
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Faculty of Agricultural Engineering, University of Agriculture, ul. Akademicka 13, 20-950 Lublin |
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vol. 4 (2004), nr. 3,
pp. 747-752
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abstract:
If freeze-drying is conducted until achieving as low a humidity as possible, the dried fruit is suitable for long-term storage without significant loss of vitamins but the process is highly energy-consuming. The period of time of freeze-drying, energy consumption and qualitative factors of the dried fruit were studied for three levels of apple dried fruit humidity. In the range of water content decrease in the dried fruit from 0.075 kg kg-1 of dry matter (7%) to 0.02 kg kg-1 of dry matter (2%) energy consumption increased considerably (according to indicator 2) and retention of L-ascorbic acid decreased (by 2%). Along with the decrease of final humidity from 16% to 2%, the process time was lengthened and for this the energy-consumption necessary to achieve 1 kg of dried fruit in a lyophilising cabinet increased over threefold, and (as a result of long-term drying) the retention of L-ascorbic acid was significantly decreased.
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keywords:
freeze-drying, energy consumption, qualitative factors
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original in:
Polish
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