Mass transfer during osmotic dehydration of pineapple.

摘要

Osmotic dehydration is a mild dehydration method for fruits and vegetables, which causes minimal changes in flavour and texture. It can also be used to incorporate additives into the dried product simultaneously. Knowledge of the effects of process variables on osmotic dehydration of fruits may help to optimise process control settings. The determination of the equilibrium water and sucrose contents, and the volume variation that occurred during osmotic dehydration of pineapple slices in a stirred sucrose solution (60% w/w) at 30, 40, and 50 C was undertaken. A mathematical model, which included shrinkage effects, based on Fick's law was developed to predict dehydration kinetics. The equilibrium water content was between 34% and 36%, and was practically independent of temperature. Equilibrium sugar content increased from 45% to 54% when the temperature was raised from 30 to 50 C. Thickness variation was independent of temperature, but was dependent on water content.