Ohmic heating-electro-thermal heating where electrical current passes through a food material. Unlike conventional heating using external elements, a volumetrically distributed heat source-the electrical resistivity of the food product-is produced within the food product development. Quality and food safety of products are important, together with minimization of energy and food processing sustainable benefits. New types of thermal processing innovations for foods that can meet the food quality and food safety concerns, as well as food sustainability requirements are sought, and ohmic heating is one promising innovation which could provide quick and uniform heating with minimal damage to food constituents.
Ohmic heating-electro-thermal heating where electrical current passes through a food material. Unlike conventional heating using external elements, a volumetrically distributed heat source-the electrical resistivity of the food product-is produced within the food product development. Quality and food safety of products are important, together with minimization of energy and food processing sustainable benefits. New types of thermal processing innovations for foods that can meet the food quality and food safety concerns, as well as food sustainability requirements are sought, and ohmic heating is one promising innovation which could provide quick and uniform heating with minimal damage to food constituents.
Increased desire for minimally processed food with well-preserved nutritional and sensory quality of foods is driving the application of ohmic heating food processing, covering beverages, dairy products, sauces, ready-to-eat products, plant-based foods and other items. Development of process automation, process control and large-scale equipment could promote the application of ohmic heating technology in food manufacturing as an efficient, high quality and sustainable food manufacturing. [1]
How ohmic heating works process is also known as electrical resistance heating or joule heating food processing. In the process, the food material is put in between two electrodes, and the alternating electric current flows through the food formulation. Because of the intrinsic electrical resistance, the electrical energy is converted directly into heat, and throughout the food it generates uniformly heat.
Instead of the conventional heating process where heat is applied from the outer surfaces to the inner food core, ohmic heating uses a volumetric heating method applies heat throughout the food matrix simultaneously, leading to efficient and rapid heating uniform temperature distribution, improved process efficiency, and reduced thermal damage to sensitive food components.
The performance of ohmic heating process is influenced by the following parameters:
Modern ohmic heating technology consists of sophisticated sensors and process control logic (automation system) to provide stringent control over the heating process to obtain uniform heating and adhere to food regulatory requirements. [2]
Increased use of ohmic heating food processing is attributed to enhanced heating efficiency, food quality and processing consistency. Ohmic heating provides the features to meet today’s food manufacturing needs which cannot be achieved through conventional thermal technologies.
An important advantage of ohmic heating is that it generates heat uniformly throughout the food product. This eliminates temperature gradients and ensures rapid processing because the product does not rely on conductive heat transfer through its external surfaces to the internal layers of the food matrix, resulting in faster and more consistent processing.
The shortened heating times afforded by ohmic heating minimize the degradation of heat sensitive nutrients. This means ohmic heating supports improved nutrient retention processing for vitamins, antioxidants and so on.
Improved ohmic heating food quality is derived from reduced heat treatment. Thus, the technology preserves color, flavor, aroma, texture and nutritional aspects of the food. Also, it provides better food texture preservation for delicate food products.
Ohmic heating can offer highly energy efficient processing because electrical energy is directly converted into heat in the food matrix, resulting in lower energy losses during the processing and can contribute to improved process sustainability.
One of the crucial benefits of ohmic heating technology is that it can support efficient particulate food heating and can process products containing both liquids and solids to give more consistent product.
The rapid heating rates achieved allow manufacturers to reduce processing cycles and enhance the production efficiency with better quality control for the products.
One of the benefits of improved ohmic heating food quality is that reduced thermal treatment obtained from the rapid and uniform heating helps preserve the color, flavor, aroma, texture and nutritional quality compared with many conventional thermal processing methods.
In addition, food texture preservation is enhanced for food products including fruits, vegetables, seafood, dairy products, and particulates; especially with minimization of both overheating of regions in the food and excessive heat treatment, manufacturers can gain good sensory quality and food safety requirements. [3] [4]
The comparison of ohmic heating vs conventional heating explains the reasons behind this technology’s growing importance in modern food manufacturing. Instead of relying on heat to travel to the food product from the outer surfaces as conventional heating processes do, ohmic heating creates heat within the food product development which results in rapid processing and uniform temperatures.
Parameter | Ohmic Heating | Conventional Heating |
Heating Mechanism | Internal heating | Surface-to-center heating |
Processing Speed | Fast | Moderate to slow |
Temperature Uniformity | High | Variable |
Energy Efficiency | High | Moderate |
Nutrient Retention | Better | Moderate |
Product Quality | Improved | May experience thermal degradation |
Particulate Processing | Highly effective | More challenging |
Processing Time | Shorter | Longer |
The ability of ohmic heating technology to provide quick, uniform heating has also led to its examination as a suitable retort processing alternative for some foods that need improved quality retention. [5]
As ohmic heating technology continues to gain industrial acceptance, new applications are emerging throughout various food categories where rapid, uniform heating and quality preservation is desired.
Food Category | Typical Applications | Key Benefits |
Beverages & Fruit Products | Juices, beverages, purees | Rapid heating, quality retention |
Dairy Products | Milk, dairy beverages | Uniform heating, product stability |
Plant-Based Alternatives | Plant-based milk, protein drinks | Improved sensory and nutritional quality |
Soups & Sauces | Soups, gravies, sauces | Consistent processing, better process control |
Ready-to-Eat Meals | Multi-component meals | Uniform heating, improved safety |
Particulate Foods | Foods containing vegetables, meat, grains, or seafood | Effective particulate food heating |
Continuous Flow Pasteurization | Liquid and particulate products | Rapid microbial control, higher throughput |
Functional Foods | Products with bioactive ingredients | Improved retention of sensitive compounds |
Industry Insight: Perhaps the most interesting ohmic heating applications is for processing foods that contain both a liquid and a solid component. By generating heat throughout the product, ohmic heating helps achieve more uniform temperature distribution while maintaining product quality. [6]
The global adoption of ohmic heating technology is growing due to food manufacturers desiring efficient, product quality, and environmentally sustainable food production. Innovations in equipment design, automation and process control have further widened the marketability of ohmic heating food processing. This is across the complete spectrum of food products.
Recent technological improvements have included:
As food processing moves towards sustainable food manufacturing, the ability of ohmic processing systems to provide energy efficient heating while maintaining food quality will lead to wider adoption on a global scale.
While ohmic processing presents many benefits over traditional heating methods, certain ohmic heating limitations must be considered when evaluating technology. For instance, the ability of the technology to heat the food efficiently is contingent upon the electrical conductivity of the food product, and as such, the characteristics of the formulation are crucial. In addition, high initial equipment investment costs for large systems can be greater than for traditional thermal processing technologies. Moreover, proper electrode maintenance, process optimization and thorough food safety validation is essential to ensure consistent process performance and regulatory compliance, although advancements are being made to increase the commercial viability and applicability of the ohmic heating technology across a wider range of food applications.
Food safety is an issue of primary importance in the commercial implementation of ohmic heating. Manufacturers should have rigorous food safety validation plans in place that effectively demonstrate that microbial inactivation is consistent and that the process is reliable.
The key elements of a food safety validation include:
Increasingly, regulatory bodies are beginning to accept ohmic heating technology as a viable thermal processing technology, providing that proper scientific validation has been performed to show effective processing and eliminates microbes. [7]
In a 2024, peer-reviewed article, published in Food Bioscience (RSC Publications), ohmic heating was proven effective in the pasteurization of mandarin juice. Researchers Basak and Thakur (IIT) found optimum conditions to be 200 V/30 s at 85°C.
Key Results at Optimal Condition (200 V/30 s):
Parameter | Result | Advantage |
Microbial Reduction | 5 log reduction | Microbially safe |
Vitamin C Retention | 90% (10% loss) | Nutrient retention processing |
Phenolics Retention | 91.6% (8.4% loss) | Superior ohmic heating food quality |
Shelf Life (4–8°C) | 42 days | Commercial viability |
Heating Rate | 0.545°C/s | Energy efficient heating |
Ohmic heating led to >99% enzyme inactivation with a minimal impact on color. When compared with ohmic heating vs conventional heating process provided 90% vitamin C retention as compared to 65-75% vitamin C retention using conventional thermal pasteurization, proving its advantages of ohmic heating.
The food safety validation was achieved at the commercial level of pasteurization. The use stainless steel electrode design food prevented contamination. This novel thermal processing method showed potential to retort processing alternative at the commercial level at 88-98% system efficiency. [8]
Reference: Basak, S., & Thakur, D. (2025). “Pasteurization of mandarin juice by ohmic heating.” Food Bioscience, 18. DOI: 10.1016/j.fbio.2024.100267.
Ohmic heating is becoming a relevant and useful food thermal processing technology for enabling efficient heating that can be employed to achieve improved product quality, nutrient retention processing, and energy efficient heating. As ohmic processing becomes more widespread throughout the food processing industry it shows great promise for improvements in food safety and efficiency and sustainability in food processing.
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