Pulsed electric fields (PEF) applications in food processing - process and equipment design and cost analysis

Abstract

The impact of pulsed electric fields (PEF) on plant and animal as well as microbial cell membranes was investigated. Electric field strength, energy input and treatment temperature were identified as key processing parameters. A critical field strength of 0.3 to 0.5 kV/cm for plant and animal and 10 to 15 kV!cm for microbial cells was observed.It was shown that extractability of fruit and vegetable juices and intracellular compounds can be enhanced after a PEF treatment. An increase of up to 7 % of apple juice yield was found in comparison to untreated samples, juice quality was equivalent. A PEF -treatment of meat pieces resulted in enhanced mass transfer during drying as well as brining of products, an improvement of water binding during cooking was found due to improved micro-diffusion of water binding agents. Inactivation ofE. sakazakii, L. monocytogenes and other pathogens was investigated in different heat sensitive liquid media, by variation of processing parameters optimum treatment conditions for a gentle and energy efficient increase of shelf life have been identified for raw milk, nutrient or vitamin solutions. To separate thermal and PEF effects kinetic studies have been performed. A combined application of PEF and mild heat showed highly synergetic effects and improved energy efficiency. Technical and industrial scale equipmenthas been developed at DIL and will be presented along with a discussion of costs of investment and operation. 1.Toepfl, S., V. Heinz, and D. Knorr, Applications of pulsed electric field technology for the food industry, in Pulsed electric field technology for the food industry, 1.

Harnessing the Structure Modifying Potential of Pulsed Electric Fields (PEF) – Food Processing Examples in Product Stabilization, Process Acceleration and Compound Extraction

“…Changes in tissue integrity were also indirectly supported by Töpfl [5] who noted that PEF had an impact on sample conductivity and weight loss.…”

“…Several microscopic studies have demonstrated physical changes in meat structure caused by PEF [1][2][3][4][5]. Changes in tissue integrity were also indirectly supported by Töpfl [5] who noted that PEF had an impact on sample conductivity and weight loss.…”

Study on a Solid-State Pulse Generator Based on Magnetic Switch for Food Treatments by Pulsed Electric Field (PEF)

“…Varity of foods have been treated by PEF for increasing the production, prolonging the quality guarantee period and saving energy [12][13][14][15][16][17]. Part of the recent research is summarized in table 1.…”

Mass Transport Improvement by PEF - Applications in the Area of Extraction and Distillation

“…An increased juice yield plays an important role in juice industry. In general mechanical, enzymatic or temperature based methods were used to rupture the apple cells for a facilitated extracting, but mostly they lead to a degradation of important juice components as well as a high energy consumption (Toepfl 2006). A PEF treatment of the apples increases the yield from 1,7 to 7,7 % in comparison to an enzymatic treatment (4,2 %) (Schilling et al, 2007) and reduces the energy consumption.…”

“…For the treatment of sliced apples, the energy consumption is 12,5 ±0,5 kJ/kg and for whole apples 7,9±0,4 kJ/kg (Grimi et al, 2011). The typical energy requirement is in a range of 60-100 kJ/kg; heating, freezing/thawing: >100 kJ/kg) the energy consumption is very low (Toepfl 2006). For tissue softening, where a lower extent of cell disintegration is required, the typical specific energy input for a PEF treatment is in a range of 1 kJ/kg.…”