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Plant Science Today (PST)

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Early Access

Comparative assessment of oxalic acid levels in fresh, dried and fermented forms of water spinach (Ipomoea aquatica Forsk.)

DOI
https://doi.org/10.14719/pst.12440
Submitted
27 October 2025
Published
15-01-2026

Abstract

The current study aimed to comparatively evaluate oxalic acid levels in fresh, dried and fermented forms of water spinach (Ipomoea aquatica Forsk.) (var. Kashi Manu). The field trial was conducted at the Experimental Farm of ICAR-IIVR, Varanasi, India, July, 2024 and estimation of oxalic acid was carried out at the Biochemical Laboratory of same research institute. The oxalic acid content was assessed by titrimetric analysis using standardized potassium permanganate (KMnO₄) solution. The results showed significant differences among treatments (p ≤ 0.01). Fresh samples showed the highest oxalic acid concentration (250.24 ± 3.08 g/100 g) whereas, the lowest value was observed in the fermented sample prepared with salt water (FSW; 22.17 ± 0.68 mg/100 g). Drying reduced oxalic acid levels to 107.66 ± 4.86 mg/100 g whereas, fermentation distinctly reduced the concentration in all treatments with reductions of 83-91 % compared to fresh samples. The decline in oxalic acid concentration during fermentation is attributed to enzymatic degradation and microbial decarboxylation processes. This result revealed that traditional fermentation particularly salt water fermentation, serves as an effective approach for reducing anti-nutritional oxalic acid in water spinach, thereby enhancing its nutritional safety and value for human consumption.

References

  1. 1. Gangopadhyay M, Das AK, Bandyopadhyay S, Das S. Water spinach (Ipomoea aquatica Forsk.) breeding. In: Advances in plant breeding strategies: vegetable crops: leaves, flowerheads, green pods, mushrooms and truffles. Cham: Springer Int Publ; 2021:183-215. https://doi.org/10.1007/978-3-030-66969-0_5
  2. 2. Srivastava R. Sustainable food production through climate resilient crop: a case study of water spinach (Ipomoea aquatica). Clim Change Environ Sustain. 2022;10(2):132-41. https://doi.org/10.5958/2320-642X.2022.00014.X
  3. 3. Austin DF. Water spinach (Ipomoea aquatica, Convolvulaceae): a food gone wild. Ethnobot Res Appl. 2007;5:123-46. https://doi.org/10.17348/era.5.0.123-146
  4. 4. Angelino D, Godos J, Ghelfi F, Tieri M, Titta L, Lafranconi A, et al. Fruit and vegetable consumption and health outcomes: an umbrella review of observational studies. Int J Food Sci Nutr. 2019;70(6):652-67. https://doi.org/10.1080/09637486.2019.1571021
  5. 5. Singh J, Srivastava GK, Kanaujia R, Pal S. Anti-nutritional compounds in vegetables. In: Advances in postharvest technologies of vegetable crops. Apple Academic Press; 2018:269-88.
  6. https://doi.org/10.1201/9781315161020-10
  7. 6. Soetan K, Oyewole O. The need for adequate processing to reduce the anti-nutritional factors in plants used as human foods and animal feeds: a review. Afr J Food Sci. 2009;3(9):223-32.
  8. 7. Siener R, Seidler A, Honow R. Oxalate-rich foods. Food Sci Technol. 2021;41(1):169-73. https://doi.org/10.1590/fst.10620
  9. 8. Zayed A, Adly GM, Farag MA. Management strategies for the anti-nutrient oxalic acid in foods: a comprehensive overview of its dietary sources, roles, metabolism and processing. Food Bioprocess Technol. 2025;18(5):4280-300. https://doi.org/10.1007/s11947-024-03726-0
  10. 9. Libert B, Franceschi VR. Oxalate in crop plants. J Agric Food Chem. 1987;35(6):926-38. https://doi.org/10.1021/jf00078a019
  11. 10. Kristl J, Sem V, Mergedus A, Zavisek M, Ivancic A, Lebot V. Variation in oxalate content among corm parts, harvest time and cultivars of taro (Colocasia esculenta L. Schott). J Food Compos Anal. 2021;102:104001. https://doi.org/10.1016/j.jfca.2021.104001
  12. 11. Moro PA, Assisi F, Cassetti F, Bissoli M, Borghini R, Davanzo F, et al. Toxicological hazards of natural environments: clinical reports from Poison Control Centre of Milan. Urban For Urban Green. 2009;8(3):179-86. https://doi.org/10.1016/j.ufug.2009.02.007
  13. 12. Usman KD, Golan S, Abdin T, Livne PM, Pode D, Duvdevani M, et al. Urinary stone composition in Israel: current status and variation with age and sex-a bicenter study. J Endourol. 2013;27(12):1539-42. https://doi.org/10.1089/end.2013.0236
  14. 13. Massey LK. Food oxalate: factors affecting measurement, biological variation and bioavailability. J Am Diet Assoc. 2007;107(7):1191-4. https://doi.org/10.1016/j.jada.2007.04.007
  15. 14. Holmes RP, Assimos DG. The impact of dietary oxalate on kidney stone formation. Urol Res. 2004;32(5):311-6. https://doi.org/10.1007/s00240-004-0437-3
  16. 15. Tundo G, Vollstedt A, Meeks W, Pais V. Beyond prevalence: annual cumulative incidence of kidney stones in the United States. J Urol. 2021;205(6):1704-9. https://doi.org/10.1097/JU.0000000000001629
  17. 16. Bargagli M, Tio MC, Waikar SS, Ferraro PM. Dietary oxalate intake and kidney outcomes. Nutrients. 2020;12(9):2673. https://doi.org/10.3390/nu12092673
  18. 17. Huynh NK, Nguyen DH, Nguyen HV. Effects of processing on oxalate contents in plant foods: a review. J Food Compos Anal. 2022;112:104685. https://doi.org/10.1016/j.jfca.2022.104685
  19. 18. Gupta PK. Nonmetals and micronutrients. In: Gupta PK, editor. Illustrated toxicology. Academic Press; 2018:225-45. https://doi.org/10.1016/B978-0-12-813213-5.00007-9
  20. 19. Heilberg IP. Update on dietary recommendations and medical treatment of renal stone disease. Nephrol Dial Transpl. 2000;15(1):117-23. https://doi.org/10.1093/ndt/15.1.117
  21. 20. Holmes RP, Goodman HO, Assimos DG. Contribution of dietary oxalate to urinary oxalate excretion. Kidney Int. 2001;59(1):270-6. https://doi.org/10.1046/j.1523-1755.2001.00488.x
  22. 21. Tamang B, Tamang JP. In situ fermentation dynamics during production of gundruk and khalpi, ethnic fermented vegetable products of the Himalayas. Indian J Microbiol. 2010;50(1):93-8.
  23. https://doi.org/10.1007/s12088-010-0058-1
  24. 22. Kamble BS, Salunkhe HJ, Girhe BE, Bankar PR, Raut TV, Nikalje DY, et al. Evaluation of oxalate ions of different fruits in ripen stages. Int J Curr Sci. 2022;12(2):129-35.
  25. 23. Sheoran OP, Tonk DS, Kaushik LS, Hasija RC, Pannu RS. Statistical software package for agricultural research workers. In: Recent advances in information theory, statistics and computer applications. Hisar: CCS HAU; 1998:139-43.
  26. 24. Zayed A, Adly GM, Farag MA. Management strategies for the anti-nutrient oxalic acid in foods: a comprehensive overview of its dietary sources, roles, metabolism and processing. Food Bioprocess Technol. 2025;18(5):4280-300. https://doi.org/10.1007/s11947-024-03726-0
  27. 25. Salgado N, Silva MA, Figueira ME, Costa HS, Albuquerque TG. Oxalate in foods: extraction conditions, analytical methods, occurrence and health implications. Foods. 2023;12(17):3201. https://doi.org/10.3390/foods12173201
  28. 26. Abu Hafsa SH, Hassan AA, Elghandour MM, Barbabosa-Pliego A, Mellado M, Salem AZ, et al. Dietary anti-nutritional factors and their roles in livestock nutrition. In: Sustainable agriculture reviews 57: animal biotechnology for livestock production. Cham: Springer Int Publ; 2022. p. 131-74. https://doi.org/10.1007/978-3-031-07496-7_4
  29. 27. Jagannath A, Kumar M, Raju PS. The recalcitrance of oxalate, nitrate and nitrites during the controlled lactic fermentation of commonly consumed green leafy vegetables. Nutr Food Sci. 2015;45(2):336-46. https://doi.org/10.1108/NFS-08-2014-0078
  30. 28. Al-Kabe SH, Niamah AK. Current trends and technological advancements in the use of oxalate-degrading bacteria as starters in fermented foods: a review. Life. 2024;14(10):1338. https://doi.org/10.3390/life14101338
  31. 29. Tamang JP, Shin DH, Jung SJ, Chae SW. Functional properties of microorganisms in fermented foods. Front Microbiol. 2016;7:578. https://doi.org/10.3389/fmicb.2016.00578
  32. 30. Rizwan D, Sidiq M, Masoodi FA. Glucosinolates in Brassica: impact of pre-harvest and processing factors. Int J Veg Sci. 2024;30(6):732-65. https://doi.org/10.1080/19315260.2024.2435001

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