MASS TRANSFER KINETICS MODEL OF OSMOTIC DEHYDRATION OF CARROTS

摘要

A model based on mass balance was developed and validated to predict the mass transfer kinetics during osmotic dehydration of carrot slices. Carrot slices, 5 mm thick, were dipped in solutions of salt (three different concentrations: 5%, 10%, and 15%) along with 50°B sugar and 0.1% sodium metabisulphite at 30℃ temperature for 10, 20, 30, 40, 50, 60, 90, 120, 150, and 180 min. A sample to solution ratio of 1:5 and a constant agitation of 150 rpm were used. The moisture loss from and solids gain by carrots increased non-linearly with the duration of osmosis at all salt concentrations, and both were higher in the initial period of osmosis than the later period. Further, both increased with increasing salt concentration. The proposed model was able to predict osmosis mass transfer data up to the equilibrium point using data for relatively short period of osmosis.