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vol. 19, nr. 1 (2012)
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Effect of osmotic pretreatment on selected rehydration properties of dried apples
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Hanna Kowalska, Agata Marzec, Katarzyna Omen
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Department of Food Engineering and Process Management, Faculty of Food Technology Warsaw University of Life Sciences, SGGW ul. Nowoursynowska159c, 02-776 Warszawa |
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vol. 19 (2012), nr. 1,
pp. 65-76
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abstract:
The aim of this study was to present the effect of osmotic dehydration pretreatment of apples cv. Idared on their rehydration properties. Osmotic dehydration of apples in sucrose solution with a concentration of 30 and 60% at 30 and 50˚C for 0.5, 1.0 and 1.5 h was used before drying. The thickness of the samples in the shape of plate with dimensions of 25 x 25 mm was 0.5 and 1.5 cm. Rehydration properties of dried apples, analysed on the basis of the relative mass gain and loss of dry matter, depended on the concentration of osmotic solution and the initial thickness of the samples. The lower concentration of sucrose solution and smaller thickness of samples influenced the increase of relative mass gain in dried apples, but the differences were less apparent in the case of rehydration carried out for 4 h compared with 1-hour rehydration. Changes in solids gain and water loss during the initial osmotic dehydration of apples before convection drying partly correlated with the relative increase in the mass loss of dry matter in rehydration dried apples. Analysed indicators of rehydration were more depended on the degree of samples dehydration expressed as water loss from apples than the increase in weight of solids gain.
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keywords:
dried apple, osmotic pretreatment, rehydration
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original in:
Polish
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