A Novel System-the Simultaneous Use of Ohmic Heating with Convective Drying: Sensitivity Analysis of Product Quality Against Process Variables

The experimental sensitivity analysis of the novel ohmic assisted drying system (OAD: simultaneous use of ohmic heating and convectional air drying), which was developed as an alternative to the traditional method, was carried out for the first time. Within the scope of the study, changes in drying time, drying characteristics and some quality parameters were examined by changing the controlled parameters (applied voltage, temperature and air velocity) of the new OAD system. For this purpose, potato, which is an important commercial food in the European continent, was used as raw material. The optimum levels of OAD were calculated as approximately 60 degrees C for drying temperature, 112 V for applied voltage and any value between 1.07 and 1.98 m/s for air velocity to minimise drying time, browning index and to maximise effective diffusivity corresponding to accelerated drying period, b* colour value. According to the results, a 32-38% improvement was achieved in drying time compared to the traditional method. In addition, no negative effect was observed on the quality properties of potato slices dried under optimum conditions compared to the control samples. Moreover, it appears as an advantage that the new method provides partial pre-gelatinisation of starch molecules, which is important for the food industry. OAD will also save both time and economy by removing the need for the blanching stage in drying processes due to the obtained significant enzyme inactivation. Considering the results, it is seen that the newly developed technique has a promising potential both for the food industry and the literature.