Rehydration Kinetics of High-Pressure Pretreated and Osmotically Dehydrated Pineapple |
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| Authors: | N.K. Rastogi A. Angersbach K. Niranjan D. Knorr |
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| Affiliation: | Author Rastogi, Angersbach, and Knorr are with Dept. of Food Biotechnology and Food Process Engineering, Berlin University of Technology, Königin-Luise- Strasse 22, D-145195 Berlin, Germany. Author Niranjan is with Dept. of Food Science and Technology, University of Reading, Whiteknights, P.O. Box 226, Reading RG6 6AP, Berkshire, U.K. Author Reastogi is on DAAD fellowship from Dept. of Food Engineering, Central Food Technological Research Institute, Mysore 570 013, India. Direct correspondence to D. Knorr (E-mail: ) |
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| Abstract: | Rehydration kinetics of high‐pressure pretreated (100, 300, and 500 MPa for 10 min) and osmotically dehydrated pineapple (Ananas comsus) cubes (2 × 2 × 1 cm) were studied at different temperatures (5, 25, and 35°C), and compared with ordinary osmotically dehydrated samples. The effective diffusion coefficients for water and solute were determined, assuming the rehydration process to be governed by Fickian diffusion. Diffusion coefficients for water absorption into the tissue as well as for solute diffusion out of the tissue were found to be lower in the samples subjected to high‐pressure treatment. Further, the diffusion coefficients decreased with increase in treatment pressure. A possible explanation for the observed decrease in diffusion coefficients can be attributed to the permeabilization of cell membranes, the release of cellular components, and structural changes of the cell materials. The diffusion coefficients were correlated with rehydration temperature (T) and treatment pressure (P) by an Eq. of the form D = A exp[–(B.P + C/T)], where A, B, and C are constants. |
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| Keywords: | rehydration high pressure osmotic dehydration mass transfer diffusivity pineapple |
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