SEASONAL DYNAMICS OF VITAMIN C CONTENT IN SOME PLANTS

12 Danish Scientific Journal No101, 2025 BIOLOGICAL SCIENCES SEASONAL DYNAMICS OF VITAMIN C CONTENT IN SOME PLANTS Zarkua M. Sokhumi State University Tbilisi https://doi.org/10.5281/zenodo.17493450 This work presents the seasonal dynamics of vitamin C content in certain plants. The plants selected for research were radish (Raphanus sativus, var. Major), onion (Allium cepa L.) and spinach (Spinacia oleracea). According to our results, the vitamin C content in the selected plants changes depending on the seasons. Seasonal variation affects the vitamin content in the plants. The vegetation is primary source of vitamins. Vitamin C (ascorbic acid) is produced in the leaves of all highest plants, less in fruit, roots and stem. Natural vitamin C is better absorbed by the body. Natural vitamin C has the same antioxidant effect as synthetic vitamin C in almost a hundredfold greater amount. In addition, natural vitamin C is excreted from the body more slowly than synthetic vitamin C. Fruits or vegetables containing this vitamin also supply other essential substances to the body and flavonoids enhance its absorption. Therefore, it is important to determine accurately its content in any food as both insufficient and excessive amounts of this vitamins can trigger irreversible pathological processes in the organism. The vitamin content in food products is highly variable and depends on many factors. Therefore, it is crucial to determine accurately its content in any food as both small and large amounts of this vitamin can cause irreversible pathological processes in the body. In the selected plants, an experiment was conducted to determine the vitamin C content and observe its seasonal dynamics. Quantitative determination of vitamin C is carried out using a redox reaction between iodine and ascorbic acid according to the following scheme [1]: Ascorbic acid is oxidized to dehydroascorbic acid while iodine is reduced to iodide ions. Starch is used as an indicator which produces a blue color with free iodine. We took three plants: radish, onion and spinach. All three were grown in the same soil and harvested in different seasons, accordingly we conducted a seasonal experiment to observe how the vitamin C content would change in both raw and dried leaves. The leaves were dried in thermostat at 100 ºC for 15-20 minutes. The first experiment was conducted in autumn, the second in winter, the third in spring and the fourth in summer. 6 g. of radish, onion and spinach leaves (the experiment was conducted separately) were finely chopped with scissors, the veins were removed from the leaves, they were crushed and ground in a porcelain mortar for 10 minutes with 20 ml of 1% hydrochloric acid. The resulting mass was transferred to a 100ml flask where it was filtered through filter paper. The oxalic acid was added to the filtrate mass to make its volume of 100ml and left it in the flask for 10 minutes. After 10 minutes 20 ml of starch was added and titrated with iodine solution. The experiment was repeated over 4 seasons; each attempt was verified three times. We took: 1% iodine solution 1% oxalic acid 2g. starch 1% hydrochloric acid The procedure of experiment: Preparation of standard iodine solution: 5% iodine solution was diluted with distilled water in a ratio of 1:20 to prepare standard iodine solution. We took 10ml beaker poured there 5% iodine solution, transferred it to a 200ml volumetric flask and filled with distilled water up to 100ml. The prepared solution was transferred to the dark bottle because the iodine is light-sensitive. Preparation of starch solution: We weighed 0.5 g. of starch in a small beaker and mixed it with 10-15ml of distilled water. 80ml boiled water was added to the resulting suspension and boiled 1-2 minutes. The prepared indicator solution was cooled. Preparation of vitamin C (ascorbic acid) solution: The powdered mass without loss was transferred to a 250 ml chemical beaker and 100ml of distilled water was added. We stirred it with a stirring rod then we transferred the resulting solution to 250 ml volumetric flask. The flask was filled with distilled water to the mark. The concentration of ascorbic acid in the resulting solution was 1mg/ml. Calculation of vitamin C content: 1ml of 0.05 molar iodine corresponds to 8.806 mg of ascorbic acid. Therefore, we calculated its content in the entire solution and then converted it to 1g. of raw material. Danish Scientific Journal No101, 2025 13 The experiment was also conducted on the dried leaves. Results: Spinach onion radish Autumn Raw spinach 6g 7.2-5ml 1ml=8.806 5ml->8.806X5=44,03 44,03:7,2=6,115. Dried spinach 1.7 – 28,3% 6,115-100% X-28,3% 100X=173,05 X=1,73 Raw onion 6g 7,2-1,7ml 1ml=8,806 1,7-> 8,806X1,7=14,97 14,97:7,2=2,079 Dried onion 2,3-38,3% 2,079-100% X-38,3% 100x=79,62 X=0,796 Raw radish 6g 7,2-7,5ml 1=8,806mg 7,5–>8.806X7.5=66.045 88,045:7,2=9,172 Dried radish. 2.8 – 46,6% 9,172-100% X=46,6% 100x=427,41 X=4,274 Winter Raw spinach 6g 7,2-6.8ml 1ml=8,806 6.8–> 8,806X6,8=59,881 59.881:7.2=8,316 Dried spinach 1.9 – 31,6% 8,316-100% X-31,6% 100x=262,78 X=2,627 Raw onion 6g 7,2-2.9ml 1ml=8.806 2.9–> 8,806X2,9=25,53 25,53:7,2=3,545 Dried onion 3,1 – 51,6% 3,545-100% X-51,6% 100x=182,92 X=1,829 Raw radish 6g 7,2-2,8ml 1ml=8.806 2.8–>8.806X2.8=24,657 24,657:7.2=3,424 Dried radish 0,739 – 12,316% 3,424-100% X-12,316% 100x=42,169 X=0,421 Spring Raw spinach 6g 7.2-5ml 1ml=8.806 5ml->8,806X5=44,03 44,03:7,2=6,115 Dried spinach 2,198 – 36,6% 6,115-100% X-36,6% 100x=223,809 X=2,238 Raw onion 6g 7,2-2ml 1ml=8,806 2ml-> 8,806X2=17,612 17,612:7,2=2,446 Dried onion 0.750 – 12,5% 2,446-100% X-12,5% 100x=30,575 X=0,305 Raw radish 6g 7,2-5ml 1ml-8,806 5->8.806X5=44,03 44,03:7,2=6,115 Dried radish 2,820 – 47% 6,115-100% X-47% 100x=287,405 X=2,874 Summer Raw spinach 6g 7,2-2ml 1ml=8.806 2ml—> 8.806X2=17,612 17,612:7,2=2.446 Dried spinach 1,400 – 23,3% 2,446-100% X-23,3% 100x=56,991 X=0,569 Raw onion 6g 7,2-3ml 1ml=8,806 3–> 8,806X3=26,418 26,418:7,2=3,669 Dried onion 1,730 – 28,83% 3,669-100% X-28,83% 100x=105,77 X=1,057 Raw radish 6g 7,2-7,7ml 1ml=8.806 7,7–> 8,806X7,7=67,806 67,806:7,2= 9,417 Dried radish 1,033 – 17,21% 9,417-100% X-17,21% 100x=162,06 X=1,62 14 Danish Scientific Journal No101, 2025 We had different results in each season. Accordingly, we concluded that seasonal changes affect the vitamin content of the plant. References: 1. Science Buddies Staff. "Which Orange Juice Has the Most Vitamin C?" Science Buddies,1Apr. 2022,https://www.sciencebuddies.org/science-fairprojects/Project ideas/Chem_p044/chemistry/whichorange-juice-has-the-most-vitamin-c. Accessed 8 Sep. 2023. 2. Li Y. Schellhorn HE. New developments and novel therapeutic perspectives for vitamin C. J Nutr; 2007; 137; 2171-84 3. G.G. Filiptsova, I.I. Smolich. Plant Biochemistry: Methodological Guidelines for Laboratory Work. Mn. BSU, 2004-60p 4. https://www.chemistry.ge/stem/view.php?id= 4 0 1 2 3 4 5 6 7 8 9 10 Autumn Winter Spring Summer Raw Vegetables Spinach Onion Radish 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 Autumn Winter Spring Summer Dried Vegetables Spinach Onion Radish