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vol. 16, nr. 1 (2010)

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Selected properties of infrared-convective dried carrot and potato
Małgorzata Nowacka, Wioleta Strachota, Dorota Witrowa-Rajchert,, Ewa Sobczak
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Department of Food Engineering and Process Management, Faculty of Food Sciences, Warsaw University of Live Sciences ul. Nowoursynowska 159 C, 02-776 Warszawa

vol. 16 (2010), nr. 1, pp. 127-136
abstract: The aim of this study was investigation of selected properties of infrared-convective dried carrots and potatoes, i.e. dry matter content, shrinkage, density, water activity, hygroscopic properties, colour, vitamin C (potato) and carotenoids content (carrots). The results were compared with those obtained for convective-dried material. It was observed that the infrared-convective drying caused large tissue shrinkage for both potato and carrot material What is more, the mentioned deformation caused an increase of the density of the final dried product. It was compared with the density of the raw material measured just before starting the infrared-convective drying process. Water activity of infrared-convective dried potatoes and carrots was lower than the water activity of convective dried material by 5.8 and 13%, respectively. Brightness of potatoes decreased in both drying processes applied. The infrared-convective method helped to produce dried material with much better ability to absorb water and also with lower shrinkage and density than those derived with the convective drying method. Vitamin C content in infrared-convective dried potato was significantly higher (by 15%) than that observed in the material dried by convection. A different situation was observed for the carotenoids content – 19% decrease in comparison with convective dried material.
keywords: infrared-convective drying, convective drying, shrinkage, density, hygroscopic properties, colour, carotenoids, vitamin C, carrot, potato
original in: Polish