Drying characteristic and physico-chemical evaluation of tender jackfruit slices during osmo-convective drying

Osmo-dehydration of tender jackfruit pieces were carried out in salt solution concentration of 6, 10, 14% at 30, 40 and 50 °C with 3:1, 4:1 and 5:1 salt solution to sample ratio. The optimum processing parameters for osmosis were found to be salt solution concentration of 10% at 40 °C with 4:1 salt solution to sample ratio for 2 h resulting in 34.0% water loss (maximum) and 6.1% salt gain (acceptable) based on initial weight of sample. Both osmosed (with optimum process parameters) and non-osmosed tender jackfruit pieces were dried at 50, 60 and 70 °C in hot air dryer. The total drying time required for osmosis and air drying of osmosed jackfruit pieces was found to be 14 h as compared to 18 h for air drying of non-osmosed sample at 60 °C. Page model was fitted well to the thin-layer drying data for both osmosed and non-osmosed jackfruit pieces. Osmotic dehydration prior to hot air drying improved the quality of tender jackfruit with good texture and acceptable colour at 60 °C drying air temperature.