Title: Effect of nonthermal pretreatment on food production and its quality

Date: 9th December 2022, Friday

Time: 1:00 pm (Central European Time)

Host: dr Bartosz Trzaskowski

The seminar will be on zoom platform with the following link:

https://uw-edu-pl.zoom.us/j/92267433515

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Abstract:

In recent years, there has been observed a growing interest in the use of nonthermal processes, which can replace traditional high-temperature food processing. Nonthermal processes as a pulsed electric field (PEF) and/or ultrasounds (US) are promising technologies, which can be used to improve the efficacy of the processes in food technology and the quality of the final product. Non-thermal processes have especially a positive effect on processes based on mass and heat transfer, which affect the acceleration of the food processing and thus result in obtaining better food quality.

Pulsed electric field (PEF) is a non-thermal technology, which mechanism is based on electroporation. During PEF treatment the formation of pores in the cell’s membrane or a disruption of the cell membrane continuity occurs. According to this effect the enhancement of the processes based on heat and/or mass transfer such as drying, osmotic dehydration, freezing, extraction, etc., is observed. Ultrasounds are a form of energy generated by sound waves with a frequency in the range of 18 kHz-100 MHz. As a result of ultrasound propagation in the plant tissue is damage of the material’s structure and activation of various chemical reactions due to several phenomena such as “sponge effect”, cavitation and effects accompanying cavitation as well as absorption of acoustic energy. These effects result in changes in the structure of plant tissue and this is used to intensify different processes like extraction, osmotic dehydration, drying, etc. Both processes are used in different food applications. Pulsed electric fields and ultrasounds, applied alone or together, are usually used as the pretreatment methods used before conventional processing. Furthermore, it can be applied during conventional processes to enhance the process as well as coupled with other techniques (conventional or unconventional) to achieve a certain purpose. Even though the mechanisms of these non-thermal processes are different, they have been used generally to acceleration the processes based on heat and/or mass transfer. Nevertheless, the nonthermal processes cause physical, chemical, and biological changes in plant tissue, which influences the quality of food product. The final effect strongly depends on matrix type, used parameters of treatment and process, and target which is planned to obtain. Thus, this indicates the need for research in this field and optimization of processing parameters for each individual raw material. The aim of the application of ultrasound and the pulsed electric field is to obtain high-quality products with minimal degradation of nutrients, preserving at the same time their thermolabile compounds, flavor, taste, texture, and overall quality.