Transport Mechanisms in Osmotic Dehydration: The Role of the Structure

• Autores: P. Fito, Amparo Chiralt Boix
• Localización: Food science and technology international = Ciencia y tecnología de alimentos internacional, ISSN-e 1532-1738, ISSN 1082-0132, Vol. 9, Nº 3, 2003 (Ejemplar dedicado a: International Conference Iberdesh 2002: Process, Structure and Functionality Editorial), págs. 179-186
• Idioma: inglés
• Títulos paralelos:
  • Mecanismos de transporte en la deshidratación osmótica: papel de la estructura
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• Dialnet Métricas: 2 Citas
• Resumen

  • Osmotic dehydration promotes water release from a cellular material immersed in a concentrated solution, while a simultaneous external solute uptake happens. Mass transfer occurs during this operation through different mechanisms to a different extent depending on process variables. The action of the different mechanisms, balanced by controlling those variables, makes possible to achieve a specific dewatering-solute uptake ratio in the final product. Mechanisms involved in mass transfer during osmodehydration of cellular tissues depend on the structural level of the tissue. The external broken cells can be easily impregnated by the external solution, and in the intercellular spaces, bulk flow of solution, water and solute diffusion occur. The bulk flow is promoted due to capillary pressure in processes carried out at atmospheric pressure. Nevertheless, when vacuum is applied to the system, capillary impregnation is promoted and when the atmospheric pressure is restored, pores are extensively flooded with the external solution and depending on the applied compression ratio. Mass transport in the intercellular spaces is mainly responsible for solute gain. At cellular level, cell wall and membranes act as non-selective and selective barriers respectively to mass transport and the transmembrane flux is responsible for most of the cell-to-cell water transport during osmotic dehydration of tissues. (A)