Investigation of Changes in the Qualitative Properties of Sour Orange Juice during the Ohmic Heating Process

Electrical treatments play an important role in conventional methods of food technology. Ohmic processing is an electrical and thermal method based on the passage of electricity through a product that acts as an electrical resistor. In ohmic heating, the temperature rises without the need for heat transfer from the solid-liquid surface. In this research, an ohmic heating device was constructed, and for the heating process, three input voltage gradients (5, 7.5, and 10 V/cm) and three process temperatures (60, 75, and 90 °C) were selected. During the thermal process, the content of total phenol, total flavonoids, and soluble solids (Brix and PH) was examined. All experiments were performed in three replications using a factorial experiment in a completely randomized design. The results were analyzed using SAS software. According to the obtained results, the voltage and temperature gradients of the process on the total phenol content, the amount of flavonoids, pH, and total soluble solids were significant at the level of 1%. The highest amount of total phenol and flavonoid content was at the voltage gradient of 5 V/cm and process temperature of 60 ° C and the lowest value was at the voltage gradient of 10 V/cm and process temperature of 90 °C. The maximum pH was observed at a voltage gradient of 5 V/cm and a process temperature of 90 ° C and the lowest value was observed at a voltage gradient of 10 V/ cm and a process temperature of 60 °C. The highest output was at a voltage gradient of 10 V/cm and the process temperature was 90 °C; the lowest value was at a voltage gradient of 5 V/cm and the process temperature was 60 °C.