Optimisation of vacuum pulse osmotic dehydration of blanched pumpkin

Pulsed vacuum osmotic dehydration (PVOD) is an efficient process for obtaining semi-dehydrated food. The effects of temperature (30-50 degrees C), solute concentration (NaCl 0-15 kg per 100 kg solution, sucrose, 15-35 kg per 100 kg solution) and vacuum pulse application (50-150 mbar and 5-15 min) on water loss (WL), solid gain (SG), water activity (a(w)) and total colour difference (Delta E) of previously blanched pumpkin slices were assessed through Plackett-Burman experimental design. Temperature was not statistically significant in the process. Later, with the aid of a central composite design (CCD), it was found that concentration of sucrose and NaCl was influent on the WL, SG, a(w) and Delta E, and the pressure and time of application of vacuum were influent on WL and SG. The optimal conditions of process were stabilised with the desirable function, and the simulated data were similar from the experimental ones.