Design and manufacture of a device for pasteurizing orange juice and its effects on the qualitative characteristics of fresh orange juice

Abstract

The research project was conducted on the Batch Ohmic Heater, which was designed and manufactured in the laboratories of the Department of Food Sciences/College of Agriculture and Forestry/University of Mosul, to be used in sterilization of orange juice. The study included the effect of Ohmic heating at voltages of 80, 110 and 220 volts on the chemical, physical and sensory properties and compared them with samples of orange juice treated by the conventional heating method (95 Cº/15 s). Ohmic heating with the applied voltage gradients (9.2, 12.64 and 25.28 V/cm) significantly (p≤0.05) preserved the total phenols content of the orange juice samples compared with the samples treated with conventional heating immediately after treatment, however, voltage gradient ( 12.64) acquired significantly (p≤0.05) higher in average total soluble solids (TSS) over other treatments for average refrigeration period (14 days) Using a voltage gradient of 12.64 V/cm for orange juice samples showed a significant decrease (p≤0.05) in the pH values compared with the other used voltage gradients. There was the highest significant increase (p≤0.05) in the concentration of vitamin C for orange juice samples treated by Ohmic heating at voltage gradient 9.2 V/cm compared with the other samples. In the study of sensory evaluation of orange juice treated by Ohmic heating at a voltage of 12.64 V/cm, which obtained the highest degree of sensory evaluation with two grades of excellent and very good within the evaluation scores used for that (1 unacceptable - 8 excellent) by the arbitrators compared with the rest of the orange juice samples.