Oxidative stress is recognized as a key pathogenetic factor in chronic non-communicable diseases, which makes the assessment of dietary antioxidant intake particularly relevant clinically. The aim of this study was to evaluate the antioxidant activity (AOA) of freshly squeezed lemon, orange, and apple juices using iodometric titration, as well as to examine the effect of heat treatment on the stability of ascorbic acid. A 1% starch solution was used as the indicator, and titration was performed with Lugol’s solution. The results showed that lemon juice had the highest AOA (28 drops to achieve a stable coloration), while apple juice showed the lowest activity (6 drops). Heating samples to 80°C for 10 minutes reduced AOA by 60–67%, confirming the thermal lability of ascorbic acid. The findings support the use of iodometry as an accessible screening method in food biochemistry and justify the recommendation to consume thermally unprocessed fruits and vegetables for the prevention of oxidative stress.
Assessment of Antioxidant Activity of Food Products by Iodometric Determination of Ascorbic Acid and Its Significance in The Prevention of Oxidative Stress
DOI:
Keywords:
Abstract
References
Jomová K., Raptová R., Alomar S. et al. Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging. Archives of Toxicology. 2023;97:2499–2574. DOI: 10.1007/s00204-023-03562-9
Kaźmierczak-Barańska J. et al. Two Faces of Vitamin C — Antioxidative and Pro-Oxidative Agent. Nutrients. 2020;12(5):1350. DOI: 10.3390/nu12051350
Forman H., Zhang H. Targeting oxidative stress in disease: promise and limitations of antioxidant therapy. Nature Reviews Drug Discovery. 2021;20:689–709. DOI: 10.1038/s41573-021-00233-1
Gęgotek A., Skrzydlewska E. Antioxidative and Anti-Inflammatory Activity of Ascorbic Acid. Antioxidants. 2022;11:1993. DOI: 10.3390/antiox11101993
Wang S.-F., Liu X., Ding M. et al. 2-O-β-d-glucopyranosyl-l-ascorbic acid, a novel vitamin C derivative from Lycium barbarum, prevents oxidative stress. Redox Biology. 2019;24:101173. DOI: 10.1016/j.redox.2019.101173
Meulmeester F., Luo J., Martens L. et al. Antioxidant Supplementation in Oxidative Stress-Related Diseases: What Have We Learned from Studies on Alpha-Tocopherol? Antioxidants. 2022;11:2322. DOI: 10.3390/antiox11122322
Miazek K., Beton K., Śliwińska A., Brożek-Płuska B. The Effect of β-Carotene, Tocopherols and Ascorbic Acid as Anti-Oxidant Molecules on Human and Animal In Vitro/In Vivo Studies: A Review. Biomolecules. 2022;12:1087. DOI: 10.3390/biom12081087
Trifunschi S.I. et al. Determination of the Ascorbic Acid Content and the Antioxidant Activity of Different Varieties of Vegetables Consumed in Romania. Sustainability. 2022;14:13419. DOI: 10.3390/su14201341
Belete A. et al. Ascorbic acid content and the antioxidant activity of common fruits commercially available in Addis Ababa. Bulletin of the Chemical Society of Ethiopia. 2023;37(2). DOI: 10.4314/bcse.v37i2.3
Syafitri N. et al. Determination of Ascorbic Acid Concentration in Myrtaceae Using the Iodometric Titration Method. Journal of Pharmaceutical Sciences. 2023;8. DOI: 10.21107/jps.v8i1
Sharaa I.E., Mussa S.A.B. Determination of Vitamin C (Ascorbic Acid) Contents in Vegetable Samples by UV-Spectrophotometry and Redox Titration Methods. International Journal of Chemistry. 2019.
Munteanu I., Apetrei C. Analytical Methods Used in Determining Antioxidant Activity: A Review. International Journal of Molecular Sciences. 2021;22:3228. DOI: 10.3390/ijms22063228
Christodoulou M.C. et al. Spectrophotometric Methods for Measurement of Antioxidant Activity in Food and Pharmaceuticals. Antioxidants. 2022;11:2161. DOI: 10.3390/antiox11112161
Doseďdel M., Jirkovský E., Macáková K. et al. Vitamin C — Sources, Physiological Role, Kinetics, Deficiency, Use, Toxicity, and Determination. Nutrients. 2021;13:615. DOI: 10.3390/nu13020615
Nibbe P., Schleusener J., Siebert S. et al. Oxidative stress coping capacity (OSC) value: Development and validation of an in vitro measurement method using EPR and vitamin C. Free Radical Biology and Medicine. 2022. DOI: 10.1016/j.freeradbiomed.2022.11.034
Njus D., Kelley P., Tu Y., Schlegel H. Ascorbic Acid: The Chemistry Underlying Its Antioxidant Properties. Free Radical Biology and Medicine. 2020. DOI: 10.1016/j.freeradbiomed.2020.07.013
Nowak D., Gośliński M., Wojtowicz E., Przygoński K. Antioxidant Properties and Phenolic Compounds of Vitamin C-Rich Juices. Journal of Food Science. 2018;83(8):2237–2246. DOI: 10.1111/1750-3841.14284
Timoshnikov V.A. et al. Redox Interactions of Vitamin C and Iron: Inhibition by Deferiprone. Antioxidants. 2020. DOI: 10.3390/antiox9050361
Rasool A., Chidi C., Rigaut S. et al. A novel combinatorial approach integrating experimental and computational analysis of antioxidant activity. PLOS ONE. 2024;20. DOI: 10.1371/journal.pone.0309881
Gulcin I. Antioxidants and antioxidant methods: an updated overview. Archives of Toxicology. 2020;94:651–715. DOI: 10.1007/s00204-020-02689-3