Osmotic dehydration kinetic of potato

P. DELLA ROCCA; R.H. MASCHERONI

Foz de Iguazu

Congreso; IUFOST World Congress of Food Science and Technology; 2012

IUFOST

The osmotic dehydration (DO) is one of the fruit preservation technologies with potential application in developing countries due to the low power consumption, the simplicity of the process and the low cost of its osmotic agents. The DO consists of immersing the product in aqueous solution of high osmotic pressure. The objective was the study of the DO kinetic in sucrose solutions at different concentration in the rank of (10- 50% m/m) and the same salt concentration (10% m/m). The potatoes were cut into 1 cm cubes and the solution was stayed at 30ºC and was shaken at 120-130 rpm with a solution mass to potatoes mass ratio of 4. In order to model the kinetic, empirical models like those of Azuara and Raoult Wack were applied. The experimental values of water loss after 4 hours of treatment were compared with the obtained with these models at infinite time. These results were very similar in spite of not to have reached the equilibrium at 4 hours. The values of water loss at infinite time obtained with the model of Azuara and the Raoult-Wack were very similar and they fit the experimental data very satisfactorily. Also a phenomenological model was used, Crank model, that represents the diffusional mechanism based on the second Fick ‘s law. The effective diffusion coefficient of water in the product for the different sucrose concentrations was calculated. The values were in the rank of (5.7 ± 0.35 - 17.4 ± 1.80) 10 10 m2/sec).