Optimisation of osmotic preconcentration and fluidised bed drying to produce dehydrated quick-cooking potato cubes

Osmotic preconcentration followed by fluidised bed drying of potato pieces to produce dehydrated quick-cooking potato was studied. Process parameters of both operations were optimised using response surface methodology. Since solid gain affects taste of the product, the process was optimised for maximum water loss and minimum solid gain. A solution of 50% sugar and 10% salt at 47 degrees C for 4 h was found to be optimum for osmotic preconcentration of potato cubes. Moisture content was reduced from 84% to 60% moisture content (w.b.). Minimisation of final moisture content and bulk density with acceptable colour was the basis for optimising the fluidised bed drying conditions. Drying at 140 degrees C for 10 min at 5.3 mis followed by thin layer air drying at 50-60 degrees C and 0.75 m/s for about 7 h was found to be optimal. Time to rehydrate/cook the processed-potato was only half that for fresh-potato. Organoleptic overall acceptability of the cooked processed-potato was almost same as that of cooked fresh-potato. (C) 2000 Elsevier Science Ltd. All rights reserved.