Pulsed Electric Field Processing to Reduce Oxalate Content in Walur Tuber: Effects of Electric Field Strength, Soaking Time, and Sequential Treatments

Rani Anggraeni, Eko Hari Purnomo, Purwiyatno Hariyadi, Feri Kusnandar, Anto Tri Sugiarto

Abstract

Walur tubers contain high levels of oxalates, which raise nutritional concerns and necessitate their reduction. Pulsed Electric Field (PEF) treatment is a non-thermal technology that applies high-voltage pulses to enhance mass transfer in plant tissues, thereby facilitating the release of oxalates from intracellular matrices. This study aimed to determine the optimal PEF conditions for reducing oxalate levels by evaluating the effect of electric field intensity, soaking time, and sequential treatments. Tuber samples were subjected to various PEF treatments, after which total oxalate content was quantified using HPLC, while structural changes were examined using SEM and TEM. The results showed that an electric field of 3.32 kV/cm effectively reduced oxalate content, while a 5-minute soaking significantly enhanced oxalate diffusion. Two consecutive PEF treatments also resulted in a reduction of oxalate levels, although this decrease was not as significant as that achieved through the combination of PEF and soaking. SEM analysis revealed fractures in calcium oxalate crystals and the formation of debris, while TEM analysis showed the cellular damage after PEF treatment at 1.08 kV/cm, indicating irreversible electroporation. The optimal conditions for oxalate reduction in walur tubers were achieved through a PEF treatment at 1.08 kV/cm combined with a 5-minute soaking. This condition yielded the lowest oxalate levels, recognized as the most energy-efficient option, resulting in statistically similar reduction of oxalate (p-value > 0.05) to that achieved with higher field strengths. These findings suggest that PEF is a promising and sustainable method to enhance the quality and safety of walur tubers.

Keywords

References

[1] E. Santosa and N. Sugiyama, “Amorphophallus species in East Nusa Tenggara Islands, Indonesia,” Tropical Agriculture and Development, vol. 60, no. 1, pp. 53–57, 2016.

[2] A. Z. Mutaqin, D. Kurniadie, J. Iskandar, M. Nurzaman, and R. Partasasmita, “Ethnobotany of suweg, amorphophallus paeoniifolius: Utilization and cultivation in West Java, Indonesia,” Biodiversitas, vol. 21, no. 4, pp. 1635–1644, 2020, doi: 10.13057/biodiv/d210444.

[3] R. Anggraeni, “Penurunan kadar oksalat umbi walur (Amorphophallus campanulatus var. sylvestris) dan karakterisasi serta aplikasi pati walur pada cookies dan mie,” M.S. thesis, Department of Food Science and Technology, Institut Pertanian Bogor, Bogor, Indonesia, 2011.

[4] G. P. Savage and L. Mårtensson, “Comparison of the estimates of the oxalate content of taro leaves and corms and a selection of Indian vegetables following hot water, hot acid and in vitro extraction methods,” Journal of Food Composition and Analysis, vol. 23, no. 1, pp. 113–117, 2010, doi: 10.1016/j.jfca.2009.07.001.

[5] X. Zheng, W. Zhu, and G. Zeng, “A case-based review of dietary management of calcium oxalate stones,” World Journal of Urology, vol. 41, no. 5, pp. 1269–1274, 2023, doi: 10.1007/s00345-023-04324-z.

[6] N. K. Huynh, D. H. M. Nguyen, and H. V. H. Nguyen, “Effects of processing on oxalate contents in plant foods: A review,” Journal of Food Composition and Analysis, vol. 112, p. 104685, 2022, doi: 10.1016/j.jfca.2022.104685.

[7] A. H. Mansoor et al., “Physicochemical, nutritional and oxalate concentration of taro tubers grown in North Sumatera, Indonesia: Effect of blanching and cooking treatments,” International Journal of Agricultural Technology, vol. 21, no. 5, pp. 1847–1862, 2025, doi: 10.63369/ijat.2025.21.5.1847-1862.

[8] S. U. Marzuki, K. Desideria, P. Yolanda, S. Rezeki, and S. Khairi, “Kinetika reduksi kalsium oksalat dan pengeringan umbi talas (Colocasia esculenta L.) pada perlakuan perendaman dengan larutan NaCl,” Agrointek, vol. 18, no. 3, pp. 638–646, 2024, doi: 10.21107/agrointek. v18i3.20208.

[9] A. Zayed, G. M. Adly, and M. A. Farag, “Management strategies for the anti-nutrient oxalic acid in foods: A comprehensive overview of its dietary sources, roles, metabolism, and processing,” Food Bioprocess Technolology, vol. 18, no. 5, pp. 4280–4300, 2025, doi: 10.1007/s11947-024-03726-0.

[10] S. Srivastava, V. K. Pandey, A. Tripathi, R. Singh, and K. K. Dash, “Ultrasound-assisted oxalate reduction vs. conventional methods: A comparative study in elephant foot yam (Amorphophallus paeoniifolius) and process optimization using response surface methodology,” Food and Humanity, vol. 2, p. 100217, 2024, doi: 10.1016/j.foohum.2023. 100217.

[11] T. Liu, D. J. Burritt, G. T. Eyres, and I. Oey, “Pulsed electric field processing reduces the oxalate content of oca (Oxalis tuberosa) tubers while retaining starch grains and the general structural integrity of tubers,” Food Chemistry, vol. 245, pp. 890–898, 2018, doi: 10.1016/j.foodchem.2017.11.085.

[12] S. H. Lee, H. M. Shahbaz, S. H. Jeong, S. Y. Hong, and D. U. Lee, “Effect of pulsed electric field treatment on cell-membrane permeabilization of potato tissue and the quality of french fries,” Italian Journal of Food Science, vol. 34, no. 3, pp. 13–24, 2022, doi: 10.15586/ijfs.v34i3.2180.

[13] K. Grzelka et al., “Pulsed Electric Field (PEF) treatment results in growth promotion, main flavonoids extraction, and phytochemical profile modulation of Scutellaria baicalensis Georgi roots,” International Journal of Molecular Science, vol. 26, no. 1, 2025, doi: 10.3390/ijms26010100.

[14] T. Kotnik, L. Rems, M. Tarek, and D. Miklavcic, “Membrane electroporation and electropermeabilization: Mechanisms and models,” Annual Review of Biophysics, vol. 48, pp. 63–91, 2019, doi: 10.1146/annurev-biophys-052118-115451.

[15] T. Kotnik, W. Frey, M. Sack, S. H. Meglič, M. Peterka, and D. Miklavčič, “Electroporation-based applications in biotechnology,” Trends in Biotechnology, vol. 33, no. 8, pp. 480–488, 2015, doi: 10.1016/j.tibtech.2015.06.002.

[16] M. L. Yarmush, A. Golberg, G. Serša, T. Kotnik, and D. Miklavčič, “Electroporation-based technologies for medicine: Principles, applications, and challenges,” Annual Review of Biomedical Engineering, vol. 16, pp. 295–320, 2014, doi: 10.1146/annurev-bioeng-071813-104622.

[17] S. Asavasanti, W. Ristenpart, P. Stroeve, and D. M. Barrett, “Permeabilization of plant tissues by monopolar pulsed electric fields: Effect of frequency,” Journal of Food Science, vol. 76, no. 1, pp. E98–E111, 2011, doi: 10.1111/j.1750-3841.2010.01940.x.

[18] G. Pataro, D. Carullo, M. A. Bakar Siddique, M. Falcone, F. Donsì, and G. Ferrari, “Improved extractability of carotenoids from tomato peels as side benefits of PEF treatment of tomato fruit for more energy-efficient steam-assisted peeling,” Journal of Food Engineering, vol. 233, pp. 65–73, 2018, doi: 10.1016/j.jfoodeng.2018. 03.029.

[19] D. Frontuto et al., “Optimization of pulsed electric fields-assisted extraction of polyphenols from potato peels using response surface methodology,” Food Bioprocess Technology, vol. 12, no. 10, pp. 1708–1720, 2019, doi: 10.1007/s11947-019-02320-z.

[20] A. T. Esser, K. C. Smith, T. R. Gowrishankar, Z. Vasilkoski, and J. C. Weaver, “Mechanisms for the intracellular manipulation of organelles by conventional electroporation,” Biophysics Journal, vol. 98, no. 11, pp. 2506–2514, 2010, doi: 10.1016/j.bpj.2010.02.035.

[21] V. R. Franceschi and P. A. Nakata, “Calcium oxalate in plants: Formation and function,” Annual Review of Plant Biology, vol. 56, pp. 41–71, 2005, doi: 10.1146/annurev.arplant.56. 032604.144106.

[22] A. E.-D. A. Bekhit, V. Suwandy, A. Carne, R. van de Ven, and D. L. Hopkins, “Effect of repeated pulsed electric field treatment on the quality of hot-boned beef loins and topsides,” Meat Science, vol. 111, pp. 139–146, 2016, doi: 10.1016/j.meatsci.2015.09.001.

[23] C. Sangketkit, G. P. Savage, R. J. Martin, and S. L. Mason, “Oxalate content of raw and cooked Oca (Oxalis tuberosa),” Journal of Food Composition and Analysis, vol. 14, no. 4, pp. 389–397, 2001, doi: 10.1006/jfca.2000.0982.

[24] M. Kandušer and D. Miklavčič, “Electroporation in biological cell and tissue: An overview,” in Electroporation and Electrofusion in Cell Biology, New York: Springer, 2008, doi: 10.1007/978-0-387-79374-0_1.

[25] E. B. Sözer, C. F. Pocetti, and P. T. Vernier, “Transport of charged small molecules after electropermeabilization: Drift and diffusion,” BMC Biophysics, vol. 11, no. 1, pp. 1–11, 2018, doi: 10.1186/s13628-018-0044-2.

[26] I. Laaz, M. Kameche, and C. Innocent, “Set up of a microbial fuel cell for the treatment of a garden compost Leachate: Impact of the external polarizing electric resistance upon the chemical oxygen demand removal,” Applied Science and Engineering Progress, vol. 16, no. 4, 2023, doi: 10.14416/j.asep.2023.05.005.

[27] H. Hanna, A. Denzi, M. Liberti, F. M. André, and L. M. Mir, “Electropermeabilization of inner and outer cell membranes with microsecond pulsed electric fields: Quantitative study with calcium ions,” Scientific Reports, vol. 7, no. 1, pp. 1–14, 2017, doi: 10.1038/s41598-017-12960-w.

[28] Y. Zhang, Z. Luo, and F. Guo, “Simulation of electroporation threshold based on the evolution of transmembrane potential and pore density,” PeerJ, vol. 13, no. 4, pp. 1–16, 2025, doi: 10.7717/peerj.19356.

[29] F. Ibis, P. Dhand, S. Suleymanli, A. E. D. M. Van Der Heijden, H. J. M. Kramer, and H. B. Eral, “A combined experimental and modelling study on solubility of calcium oxalate monohydrate at physiologically relevant Ph and temperatures,” Crystals, vol. 10, p. 1094, 2020, doi: 10.3390/ cryst10100924.

[30] M. A. Karageorgou, K. Tsakmakidis, and D. Stamopoulos, “Ferroelectric/piezoelectric materials in energy harvesting: Physical properties and current status of applications,” Crystals, vol. 14, no. 9, p. 806, 2024, doi: 10.3390/cryst14090806.

[31] A. Taha et al., “Effects of pulsed electric field on the physicochemical and structural properties of micellar casein,” Polymers, vol. 15, no. 15, p. 3311, 2023, doi: 10.3390/polym15153311.

[32] H. S. Kim, M. J. Ko, C. H. Park, and M. S. Chung, “Application of pulsed electric field as a pretreatment for subcritical water extraction of quercetin from onion skin,” Foods, vol. 11, no. 8, p. 1069, 2022, doi: 10.3390/foods11081069.

[33] F. Pillet, C. Formosa-Dague, H. Baaziz, E. Dague, and M. P. Rols, “Cell wall as a target for bacteria inactivation by pulsed electric fields,” Scientific Reports, vol. 6, p. 19778, 2016, doi: 10.1038/srep19778.

[34] S. H. Kim, J. M. Kang, Y. Park, Y. Kim, B. Lim, and J. H. Park, “Effects of bipolar irreversible electroporation with different pulse durations in a prostate cancer mouse model,” Scientific Reports, vol. 14, p. 9902, 2024, doi: 10.1038/s41598-024-60413-y.

[35] M. Niedermeier, S. J. Antreich, and N. Gierlinger, “Correlative microscopy for in-depth analysis of calcium oxalate crystals in plant tissues,” Plant Methods, vol. 21, p. 136, 2025, doi: 10.1186/s13007-025-01463-9.

[36] A. Robin, M. Sack, A. Israel, W. Frey, G. Müller, and A. Golberg, “Deashing macroalgae biomass by pulsed electric field treatment,” Bioresource Technology, vol. 255, pp. 131–139, 2018, doi: 10.1016/j.biortech.2018.01.089.

[37] A. Burnett et al., “Effect of pulsed electric fields on the lipidomic profile of lipid extracted from hoki fish male gonad,” Foods, vol. 11, p. 610, 2022, doi: 10.3390/foods11040610.

[38] M. Calleja-Gómez, J. M. Castagnini, E. Carbó, E. Ferrer, H. Berrada, and F. J. Barba, “Evaluation of pulsed electric field assisted extraction on the microstructure and recovery of nutrients and bioactive compounds from mushroom (Agaricus bisporus),” Separations, vol. 9, no. 10, p. 302, 2022, doi: 10.3390/separations9100302.

[39] B. Kumari et al., “Impact of pulsed electric field pre-treatment on nutritional and polyphenolic contents and bioactivities of light and dark brewer’s spent grains,” Innovative Food Science and Emerging Technologies, vol. 54, pp. 200–210, 2019, doi: 10.1016/j.ifset.2019.04.012.

[40] X. Rao et al., “Pulse width and intensity effects of pulsed electric fields on cancerous and normal skin cells,” Scientific Reports, vol. 12, no. 1, pp. 1–15, 2022, doi: 10.1038/s41598-022-22874-x.

[41] K. Nowosad, M. Sujka, U. Pankiewicz, and R. Kowalski, “The application of PEF technology in food processing and human nutrition,” Journal of Food Science and Technology, vol. 58, no. 2. pp. 397–411, 2021. doi: 10.1007/s13197-020-04512-4.

[42] A. G. Pakhomov, S. Grigoryev, L. Semenov, M. Casciola, C. Iang, and S. Xiao, “The second phase of bipolar, nanosecond range electric pulses determines the electroporation efficiency,” Bioelectrochemistry, vol. 176, no. 1, pp. 100–106, 2018, doi: 10.1016/j.bioelechem. 2018.03.014.

[43] J. C. Weaver and Y. A. Chizmadzhev, “Theory of electroporation: A review,” Bioelectrochemistry and Bioenergetics, vol. 41, no. 2, pp. 135–160, 1996, doi: 10.1016/S0302-4598(96)05062-3.

[44] S. Carpentieri, A. Režek Jambrak, G. Ferrari, and G. Pataro, “Pulsed electric field assisted extraction of aroma and bioactive compounds from aromatic plants and food by products,” Frontiers on Nutrition, vol. 8, p. 792203, 2022, doi: 10.3389/fnut.2021.792203.

[45] S. M. Delbaere et al., “Cell membrane permeabilization by pulsed electric field treatment impacts biochemical conversions and the volatile profile of broccoli stalks,” LWT-Food Science and Technology, vol. 187, p. 115307, 2023, doi: 10.1016/j.lwt.2023.115307.

[46] A. Wiktor et al., “The impact of pulsed electric field treatment on selected bioactive compound content and color of plant tissue,” Innovative Food Science and Emerging Technologies, vol. 30, pp. 69–78, 2015, doi: 10.1016/j.ifset.2015. 04.004.

[47] S. Brianceau, M. Turk, X. Vitrac, and E. Vorobiev, “Combined densification and pulsed electric field treatment for selective polyphenols recovery from fermented grape pomace,” Innovative Food Science and Emerging Technologies, vol. 29, pp. 2–8, 2015, doi: 10.1016/j.ifset.2014.07.010.

Full Text: PDF

Refbacks

There are currently no refbacks.

Username
Password
Remember me