This study was designed to elucidate the effects of osmotic dehydration of pumpkin slice prior to hot-air drying. Response Surface Methodology (RSM) with Central Composite Design was used to investigate the influence of three variables, namely sucrose concentration (30-60˚Brix), immersion temperature (35-65˚C) and immersion time (90-120 min). These factors increased the solid gains and decreased the water activity (aw) of the sample; while the temperature and sucrose solution concentration increased the water loss (p
Osmotic dehydration kinetics of Terung Asam (Solanum lasiocarpum Dunal) under different process temperature (35-55oC), sucrose concentration (40-60%) and immersion time (30-180 min) were studied. Results obtained indicated that water loss (WL) increased with sucrose concentration and temperature. Similarly, solid gain (SG) also increased with temperature elevation. The effective diffusivities calculated using Fick’s model were in the range of 7.7678 x 10-10 to 11.6519 x 10-10 m2s-1 for WL and 3.5462 x 10-10 to 8.1056 x 10-10 m2s-1 for SG. Meanwhile, the activation energy for moisture diffusion varied from 4.900 to 7.423 kJmol-1 and for solid diffusion from 10.440 to 14.323 kJmol-1.