Salting, drying and fermentation were among some of the first processing techniques used by early prehistoric communities for food preservation. With the advancement in science and technology more efficient and effective ways for transforming inedible or perishable raw materials into stable, safe, wholesome, nutritious and appealing food products were developed. Certain factors have played an important role in designing and development of various food processing techniques including safety and quality improvement, consumer convenience and acceptance, nutritional value, product and process cost reduction. Conventional thermal processing of food has been effective in inactivating microorganism and enzymes, but they have a negative impact on nutritional value and organoleptic properties of food. The limitations of conventional thermal processing has led to extensive research and development of alternate non-thermal processing techniques such as Pulsed Electric Field (PEF), High Pressure Processing (HPP), Ultrasound, and Supercritical fluid technology.
Food industry constantly requires innovation and reshaping for fulfilling the social, environmental and financial requirements of the 21stcentury. Pulsed electric field (PEF) is an innovative and promising non-thermal food processing technique based on the application of high voltage pulses for very short time (milliseconds to microseconds) between two electrodes that induces the electroporation phenomena in food and enables a non-invasive modification of the tissue’s structure. PEF has the ability of preserving food quality (nutritional and sensory) and extending shelf life significantly by inactivating pathogenic and spoilage microorganisms while reducing processing time, eliminating waste, valorization of by-products, reducing energy use and unit operations for processing.
The main application of PEF focuses on inactivating microorganism and enzymes in liquid or semi-solid foods such as juices, beverages (smoothies), milk products (liquid yogurt), liquid egg and other dairy products. PEF technique has also shown improvement in extraction of valuable compounds (antioxidants, oils, proteins) from plant and animal tissues through disruption of cell membrane and for intensification of food drying and dehydration. Use of PEF in meat processing has shown to improve drying, tenderization and aging of meat products. Pasteurization of food products with minimal effects on its quality can be achieved at relatively low temperature. PEF processing provides the opportunity of operation continuity, retention of vitamins and nutrients and preserving the sensory properties of food. It can be used for processing heat sensitive foods for better retention of flavors, colors and nutrients. Likewise, it has some challenges including high initial capital requirement, inability to inactivate spores and non-uniform treatment and operational problems in the presence of bubbles in products being treated. Nonetheless, PEF can be combined with other processing techniques such as high-pressure processing, ultrasound and effective temperature control technologies for improving its efficiency.
Reference:
Gómez, B., Munekata, P.E.S., Gavahian, M., Barba, F.J., Martí-Quijal, F.J., Bolumar, T., Campagnol, P.C.B., Tomasevic, I. & Lorenzo, J.M. (2019). Application of pulsed electric fields in meat and fish processing industries: An overview. Food Research International, 123, 95–105.