Use of ohmic heating assisted evaporation system in concentrating licorice root sherbet

In this thesis, it was to concentrate licorice root sherbet, a traditional beverage, to 20% water-soluble solids content using different voltage gradients under atmospheric conditions and to investigate the changes in electrical conductivity, performance, and some quality properties (total antioxidant capacity, total flavonoid content, and total phenolic content) of the samples during the concentration process. Licorice root sherbet samples were heated from 20°C to 100°C by ohmic heating under atmospheric conditions, and the evaporation process was continued until a 20% water-soluble solids content was reached at a constant evaporation temperature (100±2°C). For all experiments, 75 ml of licorice root sherbet was added to the test cell, and evaporation was carried out at 11, 13, and 15 V/cm voltage gradients. It was determined that the total processing time (heating and evaporation) for the licorice root sherbet samples varied between 2700 and 6180 s and that the required processing time shortened with increasing the applied voltage gradients value. It was determined that the relationship between electrical conductivity values and temperature increased linearly during the heating period for all voltage gradients. It was determined that the electrical conductivity values of the licorice root sherbet samples during the evaporation period varied between 0.29-2.39, 0.27-2.12 and 0.26-2.56 S/m for 11, 13, and 15 V/cm, respectively. At the end of the concentration process, it was determined that the total phenolic content of the samples varied between 162.47 and 215.54 GAE/mL, and that total phenolic content was negatively affected due to the increase in total processing time. Similarly, it was determined that the highest total flavonoid content was obtained at 15 V/cm voltage gradient. When the antioxidant capacity values of the samples were examined, it was determined that antioxidant capacity values were least affected by the evaporation process applied at a 15 V/cm voltage gradient. It was determined that the maximum energy consumption values were obtained at a voltage gradient of 11 V/cm due to the longest process time. It was determined that total power values varied between 0.049 and 0.092 kW under different process conditions, and the highest power consumption values were obtained at a 15 V/cm voltage gradient. The specific water removal rate increased with increasing voltage gradients. The efficiency of the evaporation process was found to range between 78.74% and 96.49%, and the process efficiency values increased with increasing voltage gradient. It is thought that the results obtained as a result of this thesis will fill the gap in the literature regarding pumping and evaporator systems planned to be installed in industrial sizes.