Pulsed electric field

After the pulsed electric field has been applied, a pulse of ions travels along a TOF analyzer placed at a right angle to the original ion beam. When the pulse is off, the ions have only their original velocities and continue into a different ion collector. 

L. Avrami et al, Preliminary Studies on Pulsed Electric Field Breakdown of Lead Azide , PATR 4991 (1976) 128) D.P. Tetz, Teledyne... 

Advances in the application of pulsed electric fields for the separation and analysis of large macromolecules use of multidimensional electric fields for enhanced separation of nucleic acids... 

In the interdisciplinary field of biophysics and biotechnology, the bioeffects of electric field have received considerable interest for both fundamental studies on these interaction mechanisms and potential application. However, the effects of pulsed electric field (PEF) on secondary metabolism in plant cell cultures and fermentation processes have been unknown. Therefore, it would be very interesting to find out whether PEF could be used as a new tool for stimulating secondary metabolism in plant cell cultures for potential application to the value-added plant-specific secondary metabolite production. Furthermore, if the PEF permeabilization and elicitation are discovered in a cell culture system, the combination of... 

Chalermchat, Y, Fincan, M., and Dejmek, P, Pulsed electric field treatment for solid-hquid extraction of red beetroot pigment mathematical modelling of mass transfer, J. Food Eng., 64, 229, 2004. 

Bendicho, S., Barbosa-Canovas, G. V., and Martin, O. (2002). Milk processing by high intensity pulsed electric fields. Trends Food Sci. Technol. 13,195-204. 

Evrendilek, G. A., Dantzer, W. R., Streaker, C. B., Ratanatriwong, P., and Zhang, Q. H. (2001). Shelf-life evaluations of liquid foods treated by pilot plant pulsed electric field system. J. Food Process. Preserv. 25, 283-297. 

Sepulveda, D. R., Gongora-Nieto, M. M., Guerro, J. A., and Barbosa-Canovas, G. V. (2005). Production of extended-shelf-life milk by processing pasteurized milk with pulsed electric fields. /. Food Eng. 9, 217-223. 

Soliva-Fortuny, R. C., Balasa, A., Knorr, D., and Martin-Belloso, O. (2009). Effects of pulsed electric fields on bioactives compounds in foods A review. Trends Food Sci. Technol. 20, 544-556. 

Toepfl, S., Mathys, A., Heinz, V., and Knorr, D. (2006). Review Potential of high hydrostatic pressure and pulsed electric fields for energy efficient and environmentally friendly food processing. Food Rev. Int. 22, 405-423. 

Heiger, D. N., Cohen, A. S., Aharon, S., and Karger, B. L., Separation of DNA restriction fragments by high performance capillary electrophoresis with low and zero cross-linked polyacrylamide using continuous and pulsed electric fields,. Chromatogr., 516, 33, 1990. 

The ECAP incorporates an electrostatic lens in the time-of-flight spectrometer in order to improve the mass resolution by compensating for small spreads in the energies of the ions evaporated from the specimen under the pulsed electric field. A lens design by Poschenrieder or a reflectron type of electrostatic lens is used for this purpose, and is standard equipment for metallurgical or materials applications of APFIM. These typically improve the mass resolution at full width half maximum (FWHM) from m/Am 250 to better than 2000. 

One of the key components in the system is the mass spectrometer. Fragments are ionized by a VUV laser pulse between a pair of plane parallel-plate electrodes (6 x 14 cm). One of the plane electrodes has a slit of 1 x 10 cm, which is covered by a metal mesh. The slit is parallel to the VUV laser beam and is the entrance of the mass spectrometer. Ions are accelerated by a pulsed electric field present between the plane parallel-plate electrodes, and then pass through the slit before they enter the mass spectrometer. 

Non-thermal processes other than ionizing irradiation are processes such as ultrasound, high hydrostatic pressure (HHP) and pulsed electric fields (PEFs) (Raso and Barbosa-Canovas, 2003 Ross el al., 2003). 

High hydrostatic pressure (HHP) and pulsed electric fields (PEFs) are rather novel technologies where relatively little research has been carried out. These methods have mostly been tested in combination with other decontamination methods and also mostly on either microorganisms in vitro or on foods of animal origin (e.g. milk, eggs and meat) (Raso and Barbosa-Canovas, 2003 Ross et al., 2003). More research is needed in order to find out if such methods are applicable to the fresh produce industry. 

Cortes C, Esteve MJ, Rodrigo D, Torregrosa F and Frrgola A. 2006. Changes of colour and carotenoid contents during high intensity pulsed electric field treatment in orange juices. Food Chem Toxicol 44 1932-1939. 

Odriozola-Serrano I, Soliva-Fortuny R, Hernandez-Jover T and Martfn-Belloso O. 2009. Carotenoid and phenolic profile of tomato juices processed by high intensity pulsed electric fields compared with conventional thermal treatments. Food Chem 112 258-266. 

Pulsed electric field is another alternative to conventional methods of extraction. PEF enhances mass transfer rates using an external electrical field, which results in an electric potential across the membranes of matrix cells that minimizes thermal degradation and changes textural properties. PEF has been considered as a nonthermal pretreatment stage used to increase the extraction efficiency, increasing also permeability throughout the cell membranes. 

Corrales M, Toepfl S, Butz P, Knorr D and Tauscher B. 2008. Extraction of anthocyanins from grape byproducts assisted by ultrasonics, high hydrostatic pressure or pulsed electric fields a comparison. Innov Food Sci Emerg Technol 9(1) 85-91. 

Fincan M, DeVito F and Dejmek P 2004. Pulsed electric field treatment for solid—liquid extraction of red beetroot pigment. J Food Eng 64(3) 381—388. 

Elez-Martinez P and Martin-Belloso O. 2007. Effects of high intensity pulsed electric field processing conditions on vitamin C and antioxidant capacity of orange juice and gazpacho, a cold vegetable soup. Food Chem 102(l) 201-209. 

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