Preservation of Foods with Pulsed Electric Fields – innovative research at SGGW
The use of a pulsed electric field for food production turns out to be much more beneficial compared to methods used for years. It is not so energy-intensive and enables the preservation of the health-promoting properties of products, which cannot be achieved using traditional methods. The research is conducted by one of the youngest scientists in Poland; dr hab. Artur Wiktor, prof. SGGW is only 35 years old.
It is estimated that over the next 30 years, the population of our planet will increase from 7.9 billion (as of December 2021) to 9.7 billion. By the end of the 21st century, it will reach 11 billion. The growth of the Earth’s population is just one of the challenges of food production.
Climate change and the growing awareness of consumers are significant factors affecting not only the direction of research but the market trends in general. That is why scientists look for new technological solutions that would reduce energy consumption and improve the quality of food.
Pulsed electric field (PEF) technology is a non-thermal food preservation method that has the major advantage to provide high-quality foods. It involves the use of short electricity pulses for microbial inactivation while imposing minimal detrimental influence on food quality. PEF technology involves the use of pulses having higher electric fields for only a few micro to milliseconds with intensity in the range of 10-80kV/cm. it leads to Electroporation, i.e., the process of pore formation in cell membranes as a result of the presence of an electric field. The electrical breakdown of cell membranes (electroporation) can be either reversible or irreversible, having applications in food preservation technology.
Pasteurization or sterilization are defined as traditional methods of food preservation. The food is heated up to a specific temperature to destroy microorganisms and enzymes. Due to the use of high temperatures, these methods are characterized by high energy consumption and lead to the destruction of nutritionally valuable substances and may affect the taste and smell.
PEF is called a nonthermal technology; due to its short processing times and low temperatures, foods keep their original sensorial and nutritional characteristics after processing. Duality parameters of orange juice regarding public health such as vitamin C were unaffected by the processing related to adverse quality losses in terms of juice pasteurization, says Dr Wiktor, Department of Food Engineering and Process Management, Institute of Food Sciences, SGGW.
The PEF technique is very versatile and can have many uses. Application of pulsed Electric Fields to carrots or apples helps obtain products with increased phenolic and carotenoid bioaccessibility.
Reducing the energy consumption of food production is an important task. It is estimated that the food sector consumes approx. 200 EJ of energy annually, of which nearly half is related to the production and distribution of food products.
Energy efficiency saves energy and helps reduce greenhouse gas emissions.
A number of research studies have demonstrated that the application of pulsed electric fields (PEF) as pre-treatment will shorten the duration of the freeze-drying process significantly. Drying temperature may also affect the degradation of many bioactive compounds.
Within the FOX project, financed by the European program Horizon 2020, our department may conduct research on how PEF affects the quality of drying of the selected fruits, vegetables, and mushrooms, says Dr Wiktor.
The next step will be the work focused on the development of a prototype of a mobile dryer, which will enable the expansion of some producers’ portfolios with dried fruit or vegetables. As the COVID-19 pandemic has proved, more and more consumers look for authentic food with transparent history and origin. The advantage of such a solution is its flexibility; the device can be moved depending on the needs. Drying is also a good method of managing surplus raw materials or those whose quality is insufficient to be marketed according to trading standards, e.g., dessert fruit.
Pulsed Electric Field (PEF) processing systems
The pulsed electric field is perceived as a new method, although its origins date back to the last century. Currently, it is often used to support the potato processing industry – French fries or potato chips. The PEF application equipment is becoming the standard device used in the potato industry. The PEF treatment can reduce frying oil absorption and fat content. The potatoes are also softer, which makes them easier to cut. The method can also reduce the content of acrylamide, a toxic substance that is classified as a potential cancer-causing agent.
The PEF treatment is still not widely used in the food industry. Some limitations may be caused by the costs of purchasing the appropriate equipment. Despite the fact of using PEF in medicine for years, e.g. to support cancer treatment, its use in the food industry may raise some concerns among consumers. Nevertheless, the research shows that the pulsed electric field is safe, said Prof. Artur Wiktor.