In the food industry, different heating processes are used to condense and then prevent the corruption of food. Ohmic heating is one of the new methods in which food materials act as electrical resistances. In the method, two electrodes are used to be in contact with food materials, and electricity is transmitted through them. Curd is one of those products that is obtained from heating doogh. The novelty of the present research is producing crud using Ohmic heating. An experimental system system was implemented to do this. Then the effects of voltage and electrode on the final temperature and time duration of the crud production process were investigated. The applied voltages were 60, 70, 80, and 90 V, and two electrode types, stainless steel and brass, were tested. The results showed a significant relationship between time duration process and voltage at a 1% probability level, but not for electrode type. The minimum time duration and energy consumption were obtained by steel electrode with 80 V as 57.83 s and 18.97 kJ, respectively.

Ohmic heating has an advantage over conventional indirect heating methods because heater (electrode) surfaces temperatures are comparatively lower as heat is generated within bulk fluid. This process could develop the electrodes decay or corrosion.Food preparation and safety are major issues in this modern world.in this study we focus on migration of Ohmic heating electrode components into a liquid-solid food and comparison migration in this method with conventional heating method. Concentrations of Fe, Cr, Ni, Mn, and Mo from the stainless steel electrode migrated into Ohmically and conventionally treated soup were measured. Migration of the major key metal ions from stainless steel measured by Atomic Absorbtion shows that overall Ohmic treatment yielded reduced migration residues of all metal ions, compared to the conventional retorting with similar electrodes.Concentrations of all metal ions migrated into food samples after Ohmic treatment were far lower than dietary exposure levels so that this technique can ensure the safety and quality of food supplies.

Ohmic heating is defined as a process which alternating electric current is passed through food with the primary purpose of heating it due to the electrical resistance and can be specially applied as an alternative heating method. In this research, Aloe vera gel concentrates having 0. 5-2% soluble solids were Ohmically heated up to 60° C by using four different voltage gradients (30– 60 V/cm). The dependence of electrical conductivity on temperature, voltage gradient, and concentration were obtained. Results indicated that there was a linear relationship between temperature and electrical conductivity. The range of the electrical conductivity was 0. 45 to1. 20 S/m, which was dependent on the concentration and voltage gradient, although the effect of concentration was very higher than voltage gradient. The Ohmic heating System Performance Coefficients (SPCs) were calculated by using the energies given to the system and taken by the Aloe vera gel samples and were in the range of 0. 67-0. 89 and the highest SPC (0. 89) was observed at 0. 5 % and 30 V/cm.

The present work was undertaken with an objective to study the design, development and construction and performance evaluation of a batch Ohmic heating system. Direct Ohmic heating (Joule’s heating) is a technology to warm up the food using an electric energy where electric current is passed through a material which gets heated by virtue of its electrical resistance. In this study, firstly new batch Ohmic heating containing a static cell (200-mm-long Teflon cylinder with 94 mm diameter at a constant voltage gradient of 15 V/cm) was developed and constructed. To evaluate the performance of this heating unit various food systems was used, i.e. sodium chloride solutions (concentrations: 0.2 and 0.6% w/v), starch solutions (2 and 5% w/v) and 0.5% w/v NaCl, a two-phase food systems (5% starch, 0.5% w/v NaCl and oil (1% and 10% w/v). heating rates for previously named food systems were determined by tracking and recording the temperature profiles for a given time intervals. The data indicates the heating up rate increases with increasing concentrations of starch and salt but decreases with increasing oil in food.

Due to the increasing population growth today, the need for new technologies for better food processing is felt more and more. New thermal and non-thermal technologies based on physical techniques for food preservation have the ability to meet consumer demands and deliver processed foods with high quality and long shelf life, without additives. Among these heating and food processing methods are Pushed Electric Fields (PDE), High Voltage Electric Fields (HVED), Moderate Electric Fields (MEF), Ohmic heating (OH), Pulsed Ohmic heating (POH). Meanwhile, one of the great alternative methods for heating is Ohmic heating. The Ohmic heating process is an alternative method that uses electrodes to convert electrical energy into heat. Electrical conductivity of heating materials is one of the factors that determine the effectiveness of Ohmic heating system. Ohmic heat can be produced effectively and efficiently from materials with electrical conductivity between 0. 01 and 10 S/m. Currently, there is a wide use of Ohmic heating potential in the food industry. Ohmic heating is most widely used in the food industry, including the inactivation of pathogens, enzymes, and the removal of some inappropriate compounds in food.

The moisture content of the beans and the pods of the green beans were determined and the samples were then subjected to Ohmic pretreatment at the specified levels. For this purpose, force-deformation device was used. Static loading was performed to determine the mechanical properties of the pretreated specimens. Experiments were carried out in a completely randomized design with factorial experiment. The effect of Ohmic heating parameters at three time levels of 3, 6 and 9 minutes and three voltage levels of 30, 50, 70 V and for vertical loading at one surface was investigated. The results showed that both factors (Ohmic heating time and voltage value) had a significant effect on fracture force and other mechanical properties, so that with increasing Ohmic heat duration the amount of fracture force and other mechanical properties decreased. The result of the loading was that in the fracture force section of the grain the maximum value of 3 minutes was 30 V with a value of 19. 193 N and the lowest value was 9 minutes with a voltage of 70 grain equal to 5. 58 and in the discussion of grain failure energy the highest and The lowest values were 21. 622 N and 5. 77 N respectively, which were 30 V and 3 min for maximum and 70 V and 6 min for minimum. In the discussion of the fracture force of green bean pod with grain the highest value was 30 V and 3 min time equal to 578. 13 N and 72. 35 N 35 min which was 70 V and 3 min time and also the highest and lowest energy The fracturelike fracture force of this sample at the same time and voltage were 656. 49 and 187. 38, respectively.

Carrot juice color changes from orange to brown immediately after production. Blanching is a suitable way to preserve and commercialize this product. In this study, an Ohmic device was used as a heating source, and polyphenol oxidase enzyme was selected as an indicator of enzyme inactivation sufficiency to color change of carrot juice. Fresh carrot juice was subjected to thermal processing under 3 temperature levels of 70, 80, and 90 degrees of Celsius and 4 time levels of 0, 20, 40 and 60 seconds with a constant voltage of 100 volts and the enzyme inactivation, Brix, pH and color indexes L* , a* and b* were checked. Constant values of reaction rate, activation energy, D-value and Q10   were investigated. The kinetics of inactivation of polyphenol oxidase of carrot juice samples were calculated at 70, 80 and 90 degrees of Celsius. The changes of enzyme inactivation, Brix, pH and a* parameter with increasing temperature and time were significant at 1% probability level by completely random design. The level of enzyme inactivation was also measured by the conventional water bath method and compared with the Ohmic method, and the results indicated the greater efficiency of the Ohmic method. As the temperature increased, the Brix level increased and the color of carrot juice changed from orange-yellow to orange-red (p≤0.05).

Carrot juice has a very short shelf-life after production. Pasteurization is a suitable way to preserve and commercialize this product. In this study, an Ohmic device was used as a heat source and Escherichia coli was chosen as an indicator of the effectiveness of bacterial inactivation for pasteurization. Fresh carrot juice was subjected to 3 temperature levels of 48, 55, and 62℃ and 6 time levels of 0, 30, 60, 90, 120, and 150 seconds at a constant voltage of 100 volts under thermal processing and the number of surviving bacteria was investigated. . Conventional hot water bath pasteurization was also performed and compared with the Ohmic method, which proved the greater efficiency of the Ohmic method. Ohmic pasteurization not only prevents waste of time and energy but also leads to the inactivation of bacterial vegetative forms in a very short time at high speed. The changes in surviving bacteria with increasing temperature and time were significant at the 1% probability level using a completely randomized method.  At 62℃, the best result for Escherichia coli was obtained.

Introduction: Food is composed of various compounds, and when the food quality expires, it becomes inappropriate for consumption and the end of life leads to some pathogenic microorganisms in food. So food processing is essential. In recent years, various heat treatments have been considered that have various disadvantages, so researchers are looking for alternative technologies in industrial processing to overcome these problems. Electric treatments play an important role in food heating technology and one of the methods of electric thermal processing is Ohmic processing, that Ohmic heat is based on the flow of electricity through a product. The purpose of this study was to investigate the effect of voltage and weight loss on the amount of energy and exergy during this process in order to obtain the best amount of energy consumed during the heating process, since the most common way to heal the heating is by heating. In addition to maintaining the product's qualitative characteristics, the product has to carefully monitor its own system parameters. Materials and Methods: The sour oranges were purchased from a garden located in the city of Gorgan, Golestan province. The prepared oranges were washed and divided into two halves in the middle and immediately after purchase, all samples of juice were taken manually in the same conditions and the samples were prepared to conduct the test during the Ohmic process with voltage gradients and the percentages of different weight loss to investigate the amount of energy efficiency, exergy efficiency, exergy loss, and improvement potential during the process. For the heating process, three voltage gradients of 8. 33, 10. 83 and 13. 33 V cm-1 and three percentage values of weight loss of 10% (from 90 g to 81 g), 20% (from 90 g to 72 g), and 30% (from 90 g to 63 g) were selected. Then, the energy and exergy consumed during the process were calculated and analyzed using a factorial experiment in a completely randomized design with SAS statistical software. Results and Discussion: Based on the results, it can be concluded that the voltage gradient and weight loss percentages are significant for energy efficiency, exergy efficiency, exergy, and potential improvement at 1% level. Increasing the voltage gradient increases the efficiency of energy and exergy and reduces the potential for recovery and exergy is wasted. The highest energy efficiency was 91. 6% in the 13. 83 V cm-1 voltage gradient and the weight loss percentages 10% and the lowest value was 51. 51% in the voltage gradient of 8. 33 V cm-1 and the weight loss percentages 30%. The maximum improvement potential was 8. 33 V cm-1 and the weight reduction was 30% and the lowest value was at 13. 33 V cm-1 voltage gradient and 10% weight loss percentages. The highest exergy efficiency of 59. 51% was found in the 13. 83 V cm-1 voltage gradient and the weight loss percentage was 30% and the lowest value was 31. 88% on a voltage gradient of 8. 33 V cm-1 and a weight percentage of 10%. Conclusions:-By increasing the voltage gradient, the energy efficiency had increased and there was a significant difference between all the volatility gradients.-For exergy efficiency, when the voltage gradient increased, the exergy efficiency amount increased, and in all percentages weight loss was a significant difference between the voltage gradient.-By increasing the voltage gradient, the amount of exergy loss decreased significantly and with increasing percentage weight loss, this amount was significantly increased.-The improvement potential was reduced by increasing the voltage gradient and there was a significant difference between the voltage gradients for the improvement potential.