ASPECTS REGARDING THE PRESERVATION OF FOOD PRODUCTS USING

ASPECTS REGARDING THE PRESERVATION OF FOOD PRODUCTS USING HIGH VOLTAGE PULSED ELECTRIC FIELD SORICA E. 1), VINTILĂ M. 2), SORICA C. 1), GRIGORE A. I. 1), CRISTEA M. 1), VLĂDUŢOIU L. 11) INMA Bucharest / Romania; 2) ICDIMPH Horting / Romania E-mail: postelnicu. elena@yahoo. com RESULTS AND DISCUSSIONS INTRODUCTION Foods are biological substances from agriculture which, in order to be consumed for a long time, must be subjected to operations designed to increase their shelf life unaltered. This is possible by applying primary conditioning or industrialization methods, in which case finished consumer products are obtained and whose shelf life is often longer than conditioning. Increasing the shelf life of food in healthy conditions can be achieved by various methods which, in general, can be classified as follows: - separation of microorganisms by physical processes; - reducing to stopping the development of microorganisms; - destruction of microorganisms by various means; - combined methods. MATERIAL AND METHODS The category of modern preservation methods includes thermal and athermal methods. The most important modern athermal preservation methods are: - preservation with the help of high pressures; - preservation by means of the magnetic field; - preservation by means of ultra-short light pulses; - conservation with the help of the high voltage pulsed electric field. The pulsed electric field (PEF) treatment method is a non-thermal food preservation method that uses electricity for microbial inactivation with minimal negative effects on food quality, electric pulses destroying microbial cell membranes. PEF can be used for pasteurizing liquid foods and pasta products, but also for extracting fruit and vegetable juices. The membrane of plant cells can be permeabilized by electrical pulses and thus liquids are released easily and completely. Preserving food with PEF provides products with very good taste and superior nutritional value. Foods treated in this way keep fresh their aroma, taste and appearance. High voltage electrical pulses (PEF or pulsed electric field) have the highest antimicrobial potential compared to classical techniques, such as cold treatment and pasteurization, thus being able to successfully replace, in whole or in part, classical thermal preservation processes During this treatment, the lysis of microbial cells is caused by irreversible structural changes within the membranes, by the formation of pores and the destruction of the semipermeable barrier of the membrane. There are various companies that produce equipment based on pulsed electric fields, both for the food and beverage industry and for the scientific sector. The Elea company (Germany), produces a wide range of equipment (Elea Cool. Juice 10, 100, 1000; Elea Smooth. Cut ONE; Elea PEFPilot) for the treatment of liquids, viscous products and horticultural products, in pulsed electric field. The Cool. Juice system (fig. 1) is intended for the treatment within pulsed electric field (PEF) of liquid or viscous products: juice, smoothies, milk, wine and other liquid consumables, at a much lower temperature than traditional thermal pasteurization. The Smooth. Cut system (fig. 2), with the treatment belt, is ideal for the treatment of tubers, roots, vegetables and fruits. The treatment of vegetables with PEF at low temperatures, replaces the need to bleach potatoes and other products before cutting. Fig. 1. Cool. Juice system Fig. 2. Smooth. Cut system Pulsemaster (USA) provides pulsed electric field (PEF) based systems for both the food and beverage industry and the science sector. The industrial solution for the treatment of PEFs of solids, semi-solids and liquids is known as Conditioner. Under the brand name Solidus (fig. 3) there is the pilot plant, with discontinuous operation, which treats solids and semi-solids for research purposes and can be used for micro production. Under the brand name Liquidus (fig. 4), there is a pilot plant, with continuous operation, which treats liquids for research purposes and can be used for small production turnovers. Fig. 3. Solidus system Fig. 4. Liquidus system CONCLUSIONS The pulsed electric field (PEF) treatment method is a non-thermal food preservation method that uses electricity for microbial inactivation with minimal negative effects on food quality. One of the advantages of using a pulsed electric field over thermal processing methods, which ensures artificial sterilization of food, is the low amount of heat produced. As a result of the small increase in temperature during processing, foods retain their "fresh" physical, chemical and nutritional characteristics and have a satisfactory shelf life when stored in the environment. Preserving food with the help of PEF offers products with very good taste and superior nutritional value. Foods treated in this way keep their aroma, taste and appearance fresh. Acknowledgements: This work was supported by a grant of the Ministry of Agriculture and Rural Development on the Sectoral Plan for Research and Development in the field of Agriculture and Rural Development – ADER 2022, contract no. 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