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vol. 16, nr. 2 (2010)


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Some physical properties of pumpkin tissue osmotically dehydrated in sugar solutions
Agata Pękosławska-Garstka, Andrzej Lenart
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Faculty of Food Sciences, Warsaw University of Life Sciences ul. Nowoursynowska 159c, 02-776 Warszawa

vol. 16 (2010), nr. 2, pp. 413-422
abstract: The aim of this study was to analyse changes in selected physical properties of osmodehydrated pumpkin tissue. The impact of the type of osmotic substance on the water content, increase of dry substance in the material and its density, water activity and colour changes were determined. Pumpkin of variety Justynka F1 was used in this study. Pumpkin tissue was cut into cubes of 10 mm. Osmotic solutions were prepared from glucose, sucrose and starch syrup at a concentration of 40%. The process was carried out at a temperature of 40oC for time ranging from 0 to 300 minutes; the weight ratio of raw material to osmotic solution was 1:4. The physical properties of osmotically dehydrated pumpkin tissue differed depending on the osmotic substances. The process of dehydration caused an increase in material density, the largest when a glucose solution was used and the smallest using starch syrup. Pumpkin tissue dehydrated in glucose solution was characterized by the lowest water content and the highest solids gain. Water activity of samples after 300 minutes of dehydration was reduced from 0.988 to 0.981 in the solution of starch syrup, to 0.977 in the sucrose solution, and to 0.961 in the glucose solution.
keywords: osmotic dehydration, physical properties, pumpkin tissue
original in: Polish