Conventional extraction methods come with various shortcomings, such as low yields and efficiency, large solvent consumption, or long processing times. Novel, more refined extraction methods are being developed to address those issues. Pulsed electric field extraction (PEF) is one such method that is garnering attention in the scientific community.
What is PEF?
PEF is a nonthermal technology that sends very quick—between nanoseconds and microseconds—high-voltage pulses through the sample, placed between two conducting electrodes. [1] This causes the cell membrane of the sample to become more conductive, porous, and permeable. This helps compounds within the cell membrane to pass through and be released into the surrounding solution, from where they can be extracted.
Thulasidas et al [1] explain that “Exposing cells to electric field separates molecules according to their charge under the dipole nature of cell membrane molecules. Pulsed electric field temporarily undermines the lipid bilayer and the proteins of cell membranes.” This method is generally most effective with liquid foods, as the electric current flows more seamlessly through them.
Potential PEF Benefits & Limitations
PEF has been found to be an efficient extraction method on all counts—cost, energy, and time, in addition to being sparing to the environment. [1]
Moreover, PEF is nonthermal, meaning it helps preserve the targeted molecules’ chemical properties by avoiding the degenerative effects of heating. [2] Instead, PEF generates minimal ohmic heat and mostly relies on electric pulses causing poration to improve extraction performance. [3] In a study on hop pellets, PEF boosted concentrations of alpha- and beta-acids as well as sesquiterpenes; the hops also maintained (or increased) antiradical activity upon extraction. [4] With white button mushrooms, PEF significantly boosted extraction of polysaccharides, polyphenols, and proteins compared to conventional extraction. [3]
PEF also tends to be employed for pre-treatment of the sample, a preliminary step to improve extraction results, especially in terms of selective extraction of different intracellular components (for example, certain proteins from microalgae). [5] The method can also be used to deactivate certain harmful pathogens and bacteria. [6]
Final Word
PEF seems like a novel method, but the research already provides a solid body of promising evidence regarding its potential and advantages on all fronts.
References:
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- Thulasidas JS, et al. Pulsed electric field for enhanced extraction of intracellular bioactive compounds from plant products: An overview. Novel Approaches in Drug Designing & Development. 2019;5(2):26-31. [Impact Factor: 0.578, Times Cited: 1 (Semantic Scholar)]
- Martínez JM, et al. Pulsed electric field‐assisted extraction of valuable compounds from microorganisms. Comprehensive Reviews in Food Science and Food Safety. 2020;19:530-552. [Impact Factor = 9.912, Times Cited = 9 (Semantic Scholar)]
- Xue D, Farid M. Pulsed electric field extraction of valuable compounds from white button mushroom (Agaricus bisporus). Innovative Food Science & Emerging Technologies. 2015;29:178-186. Impact Factor = 4.477; Times Cited = 31 (Semantic Scholar)
- Ntourtoglou G, et al. Pulsed electric field extraction of α and β-acids from pellets of Humulus lupulus (Hop). Front Bioeng Biotechnol. 2020;8(297). Impact Factor = 3.644; Times Cited = 2 (Semantic Scholar)
- Parniakov O, et al. Pulsed electric field and pH assisted selective extraction of intracellular components from microalgae Nannochloropsis. Algal Research. 2015(8):128-134. Impact Factor = 4.008; Times Cited = 95 (Semantic Scholar)
- Mosqueda-Melgar J, Elez-Martínez P, Raybaudi-Massilia RM, Martín-Belloso O. Effects of pulsed electric fields on pathogenic microorganisms of major concern in fluid foods: a review. Crit Rev Food Sci Nutr. 2008;48(8):747-759. doi:10.1080/10408390701691000. Impact Factor = 7.862; Times Cited = 91 (Semantic Scholar)
Image Credits: Joshualudwig, CC BY-SA 4.0
