2. EXPERIMENTS Important source of knowledge at education of scientific subjects

3. ESTIMATION OF VITAMIN C IN FRUIT AND VEGETABLE JUICES The aim of experiment is checking the relative amount of vitamin C in different juices.

4. WHAT IS VITAMIN C? Vitamin C, ascorbic acid, a water soluble vitamin, which plays a major role in the cellular oxidation, especially in the tyrosine oxidation and reduction processes. Vitamin C increases body resistance, what is essential to maintain correct condition of the connective tissue. It facilitates the absorption of iron. Its deficiency causes scurvy.

5. MATERIALS

7. A beaker is a simple container for stirring, mixing and heating liquids. Pasteur pipettes, also known as droppers,are used to transfer small quantities of liquids

8. TESTING JUICES 1)Orange 2)Pomagranate 3)Lemon 4)Carrot 5)Celery 6)Tomato 7)Parsley 8)Cherry 9)Grapefruit 10) Apple

9. PROCEDURE Preparing the solution of starch including iodine Pour starch to the bowl or beaker. Next, pour hot water from kettle to the bowl. Then, put the bowl into cold water and blend the solution quickly. When the solution looks like a jelly you must add drops of iodine and blend it. The solution is ready when it stained blue.

10. START OF THE EXPERIMENT

11. PROCESS OF THE EXPERIMENT Note the number of iodine solution drops which are being put into each juice Add the iodine solution to the test tube drop by drop until it changes the colour into violet-blue Add the iodine solution drops to the test tube

12. RESULTS ExtractNumber of drops of iodine solution orange6 pomagranate5 lemon2 carrot8 celery7 tomato9 parsley6 cherry3 grapefruit2 apple3 Lemon and grapefruit juice were the ones that changed colour in the shortest time. Tomato juice required the biggest amount of iodine solution to change its colour.

13. THE RELATIVE LEVEL OF VITAMIN C IN DIFFERENT JUICES

14. CONCLUSIONS All of the examined juices contain vitamin C, however its content is different. The biggest amount of vitamin C in examined extracts was found in the fresh lemon juice prepared in the lab as well as in the juice of red grapefruit which was bought in the shop. The least content of vitamin C was reported in the essence of vegetables such as parsley, carrot and tomato. Vitamin C was also detected in apple and grapefruit juices containing preservatives.

15. EXPERIMENT CONDUCTED BY Marika Karasek student PhD Anna Gruszczyńska biology teacher