Abstract

Availability of micronutrients remains a major global concern. Fortified foods are inherently rich in vitamins and minerals; for instance, folic acid, or vitamin B₉, is essential for preventing such health issues as neural tube defects in newborns. However, the efficacy of functional food depends on the bioavailability and solubility of the fortifying nutrients.
This study focused on the solubility folic acid in aqueous solutions with citric, ascorbic, and succinic acids at various concentrations (3, 5, and 10%). The methods of UV spectroscopy and high-performance liquid chromatography (HPLC) were employed to analyze the solubility of folic acid, with the resulting data processed using standard statistical methods.
The dissolution medium had a reliable impact on the solubility of folic acid. Selecting an appropriate dissolution medium proved crucial for enhancing the bioavailability of folic acid in food fortification. The 10% aqueous solution of aminoacetic acid (glycine) demonstrated the greatest potential under standard conditions. This solution achieved the highest levels of folic acid absorption and release, surpassing those for the aqueous solution of folic acid. The absorption curves suggested a uniform molecular distribution within the solution, as well as the stability of the dissolved form.
The results can be used to optimize existing food fortification technologies, thereby helping to prevent folic acid deficiency.

Keywords

Folic acid, micronutrients, aqueous acid solution, glycine, solubility, UV spectroscopy

References

1. Unnevehr LJ, Pray C, Paarlberg R. Addressing micronutrient deficiencies: Alternative interventions and technologies. AgBioForum. 2007;10(3):124–134.
2. Ashraf SF. Food fortification as a sustainable global strategy to mitigate micronutrient deficiencies and improve public health. Discover Food. 2025;(5):201. https://doi.org/10.1007/s44187-025-00512-5
3. Stevens GA, Beal T, Mbuya MNN, Luo H, Neufeld LM. Micronutrient deficiencies among preschool-aged children and women of reproductive age worldwide: a pooled analysis of individual-level data from population-representative surveys. The Lancet. Global Health. 2022;10(11):e1590-e1599. https://doi.org/10.1016/S2214-109X(22)00367-9
4. Biswal VL. Yashwanth BS, Murthy PS. Dietary enhancement of coffee with folic acid: A nutritional approach. Food Chemistry. 2025;(488):144881. https://doi.org/10.1016/j.foodchem.2025.144881
5. Kiani AK, Donato K, Aquilanti B, Velluti V, Matera G, et al. Main nutritional deficiencies. Journal of Preventive Medicine and Hygiene/ 2022;63(2):e93-e101 https://doi.org/10.15167/2421-4248/jpmh2022.63.2S3.2752
6. Zimmermann MB, Jooste PL, Pandav CS. Iodine-deficiency disorders. Lancet. 2008;372:1251–1262. https://doi.org/10.1016/S0140-6736(08)61005-3
7. Blencowe H, Kancherla V, Moorthie S, Darlison MW, Modell B. Estimates of global and regional prevalence of neural tube defects for 2015: a systematic analysis. Of the New York Academy of Sciences. 2018;1414(1):31–46. https://doi.org/10.1111/nyas.13548
8. Jääskeläinen T, Itkonen ST, Lundqvist A, Erkkola M, Koskela T, et al. The positive impact of general vitamin D food fortification policy on vitamin D status in a representative adult Finnish population: evidence from an 11-y follow-up based on standardized 25-hydroxyvitamin D data. American journal of clinical nutrition. 2017;105(6):1512–1520. https://doi.org/10.3945/ajcn.116.151415
9. Mannar MV, Hurrell RF. Food fortification in a globalized world. New York: Academic Press; 2018. 395 p. https://doi.org/10.1016/C2014-0-03835-X
10. Mathur PK, Dave P, Fuller SI, Cuero K, Chiu A, et al. Beneficial effects of folic acid fortification in the prevention of Spina Bifida and reducing the orthopaedic procedures: A narrative review of the current literature. Journal of Orthopaedic Reports. 2023;2(3):100175. https://doi.org/10.1016/j.jorep.2023.100175
11. Perry J, Refsum H. Prospective study of serum total homocysteine concentrations and risk of stroke in middle aged British men. The Lancet. 1995;346(8987):1395–1398.
12. Petri M, Roubenhoff R. Plasma homocysteine as a risk factor for atherothrombotic events in systematic lupus erythematosus. The Lancet. 1996;348(9035):1120–1124.
13. Lucock M. Folic acid: Nutritional biochemistry, molecular biology, and role in disease processes. Molecular Genetics and Metabolism. 2000;71:121-138. https://doi.org/10.1006/mgme.2000.3027
14. Mills JL, Kirke PN, Molloy AM, Burke H, Conley MR, et al. Methylenetetrahydrofolate reductase thermolabile variant and oral clefts. American Journal of Medical Genetics. 1999;86:71–74.
15. Slattery ML, Potter JD, Samowitz WD, Schaffer M. Leppert Methylenetetrahydrofolate reductase, diet, and risk of colon cancer. Cancer Epidemiol Biomarkers Prevention. 1999;8:513–518.
16. Clarke R, Smith AD, Jobst KA, Refsum H, Sutton L, Ueland PM. Folate, vitamin B12 and serum total homocysteine levels in confirmed alzheimers disease. Archives of Neurology. 1998;55:1449–1455. https://doi.org/10.1001/archneur.55.11.1449
17. James SJ, Pogribna M, Pogribny IP, Melnyk S, et al. Abnormal folate metabolism and mutation in the methylenetetrahydrofolate reductase gene may be maternal risk factors for Down’s syndrome. American Journal of Clinical Nutrition. 1999;70:495–501.
18. Kancherla V, Botto LD, Rowe LA, Shlobin NA, Caceres A, et al. Preventing birth defects, saving lives, and promoting health equity: an urgent call to action for universal mandatory food fortification with folic acid. The Lancet. Global Health. 2022;10:e1053-e1057. https://doi.org/10.1016/s2214-109x(22)00213-3
19. Toivonen KI, Lacroix E, Flynn M, Ronksley PE, Oinonen KA, et al. Folic acid supplementation during the preconception period: a systematic review and meta-analysis. Preventive Medicine. 2018;114:1-17. https://doi.org/10.1016/j.ypmed.2018.05.023
20. Rodrigues VB, Silva EN, Santos MLP. Cost-effectiveness of mandatory folic acid fortification of flours in prevention of neural tube defects: A systematic review. PLoS One. 202;16:e0258488. https://doi.org/10.1371/journal.pone.0258488
21. Ismail S, Eljazzar S, Ganji V. Intended and unintended benefits of folic acid fortification – A narrative review. Foods. 2023;12(8):12081612. https://doi.org/10.3390/foods12081612
22. Chadare FJ, Idohou R, Nago E, Affonfere M, Agossadou J, et al. Conventional and food-to-food fortification: An appraisal of past practices and lessons learned. Food Science and Nutrition. 2019;7(9):2781–2795. https://doi.org/10.1002/fsn3.1133
23. Babich O, Larina V, Ivanova S, Tarasov A, Povydysh M, et al. Phytotherapeutic approaches to the prevention of age-related changes and the extension of active longevity.Molecules. 2022;27:2276. https://doi.org/10.3390/molecules27072276
24. Ivanova S, Prosekov A. Study of the antioxidant potential of uv-treated vegetables. Nutraceuticals. 2022;27:289–299. https://doi.org/10.3390/nutraceuticals2040022
25. Ponasenko A, Sinitsky M, Minina V, Vesnina A, Khutornaya M, et al. Response and lipid metabolism gene polymorphisms are associated with the risk of obesity in middle-aged and elderly patients. Journal of Personalized Medicine. 2022;12(2):238. https://doi.org/10.3390/jpm12020238
26. Martins ICB, Forte A, Diogo HP, Raposo LR, Baptista PV, et al. Solvent-free strategy to prepare amorphous salts of folic acid with enhanced solubility and cell permeability. Chemistry–Methods. 2022;2(6):e202100104. https://doi.org/10.1002/cmtd.202100104
27. Avdeef A. Predicting solubility of new drugs. London: CRC Press; 2024. 1730 p. https://doi.org/10.1201/9781032625256
28. Vyshkovsky G. L. Register of Medicines of Russia. Encyclopedia of Medicines. Moscow: RLS; 2001. 1518 p. (In Russ.)
29. Pharmacopoeial monograph. Folic acid. [cited 2025 Oct 10]. (In Russ.) Available from: https://pharmacopoeia.regmed.ru/pharmacopoeia/izdanie-15/2/2-1/folievaya-kislota/
30. General pharmacopoeial monograph: Ultraviolet and visible spectrophotometry. [cited 2025 Oct 10]. (In Russ.) Available from: https://pharmacopoeia.regmed.ru/pharmacopoeia/izdanie-15/1/1-2/1-2-1/1-2-1-1-metody-spektralnogo-analiza/spektrofotometriya-v-ultrafioletovoy-i-vidimoy-oblastyakh/
31. Method for determining folic acid in fortified foods. [cited 2025 Oct 10]. (In Russ.) Available from: https://meganorm.ru/Index2/1/4293736/4293736986.htm
32. Edwards AA, Alexander BD. Organic applications of UV-visible absorption spectroscopy. Encyclopedia of Spectroscopy and Spectrometry (Second Edition). 2010;2030-2039. https://doi.org/10.1016/B978-0-12-374413-5.00013-0
33. Skorik NA, Vostretsova EN. Solubilities of Folic Acid and Selected Synthesized Metal Folates. Russian Journal of Inorganic Chemistry. 2019;64(2):1319–1325. (In Russ.) https://doi.org/10.1134/S0044457X19120171
34. Magri VR, Rocha MA, Matos CS, Petersen PAD, Leroux F, et al. Folic acid and sodium folate salts: Thermal behavior and spectroscopic (IR, Raman, and solid-state 13C NMR) characterization. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2022;273:120981. https://doi.org/10.1016/j.saa.2022.120981
35. Younis IR, Stamatakis MK, Callery PS, Meyer-Stout PJo. Influence of pH on the dissolution of folic acid supplements. International Journal of Pharmaceutics. 2009;367(1–2):97–102. https://doi.org/10.1016/j.ijpharm.2008.09.028
36. Đuriš J, Čalija B, Vidović B, Dobričić V, Milić J, et al. Comparative analysis of mechanical and dissolution properties of single- and multicomponent folic acid supplements. Journal of Food Composition and Analysis. 2017;60:17–24. https://doi.org/10.1016/j.jfca.2017.03.005
37. Wu KZ, Li X, Hou C, Qian Y. Solubility of folic acid in water at pH values between 0 and 7 at temperatures (298.15, 303.15, and 313.15) K. Journal of Chemical & Engineering Data. 2010;55(9):3958–3961. https://doi.org/10.1021/je1000268
38. Bottari E, D'Ambrosio A, De Tommaso G, Festa MR, Iuliano M. Solubility of folic acid and protonation of folate in NaCl at different concentrations, even in physiological solution. Analyst. 2021;146(7):2339–2347. https://doi.org/10.1039/d1an00013f
39. Pérez-Carreón K, Martínez LM, Videa M, Cruz-Angeles J, Gómez J, et al. Effect of basic amino acids on folic acid solubility. Pharmaceutics. 2023;15:2544. https://doi.org/10.3390/pharmaceutics15112544
40. Kasten G, Lobo L, Dengale S, Grohganz H, Rades T, et al. In vitro and in vivo comparison between crystalline and co-amorphous salts of naproxen-arginine. European Journal of Pharmaceutics and Biopharmaceutics. 2018;132:192–199. https://doi.org/10.1016/j.ejpb.2018.09.024
41. LysenkoAA, Zhirkova EV, Platov YuT, Martirosyan VV, Chernykh VYa, et al. Classificationof wheat flour by rheological properties using an alveograph and multidimensionalanalysis methods. Food Industry. 2025;(6):66–70. (In Russ.) https://doi.org/10.52653/PPI.2025.6.6.014