Optimization of Radiofrequency Assisted Heat Pump Drying of Carrot

The optimization of radiofrequency (RF) assisted heat pump (HP) drying of carrot was studied. Response surface methodology (RSM) was used for optimization of drying process. The input parameters as independent variables were the drying air temperature, drying air velocity and RF power and the output parameters as response variables were drying time and color change index. The multi-factor optimization problem was solved by Stagraphics Centurion 17 software on a computer to determine the optimal drying condition of input parameters. The processing results determined the optimal drying condition as the drying air temperature of 49.5 °C, the drying air velocity of 1.75 m/s and RF power of 1.49 kW. Under these optimal conditions, the yield of output parameters was drying time of 293 min and color change index of 7.57. Besides, the analysis of variance defined the adequacy of the regression models for output parameters and the effect levels of the input parameters on the output parameters in drying process.