Objective of Effects of Heat on Vitamin C in Tomatoes Science Fair Project: Determine if tomatoes maintain their levels of vitamin C after being exposed to heat.
Student: Bogdan Maxim
The project will be done using the titration reaction between tomatoes juice (the titrant), distilled water and cornstarch solution plus iodine tincture as the titration solution. My expected result is that Vitamin C in tomatoes will decrease when heated because Vitamin C is water soluble and is affected by heat.
Information on Vitamin C
Vitamin C is found in fresh fruits, berries and vegetables. It is one of the water-soluble vitamins. It is important in wound healing. Without enough vitamin C, a person can get a sickness called scurvy. Lack of vitamin C was a serious health problem on long ocean trips where supplies of fresh fruit were quickly used up. Many people died from scurvy on such trips. Vitamin C was first discovered in 1928. In 1932, it was proved to stop the sickness called scurvy.
- A solution containing tomato juice and 200 ml distilled water was made
- The solution was filtered to remove seeds
- A 30ml sample was set aside as the control (unmodified solution)
- The remaining solution was heated on a gas stove for 1 minute and half
- The solution was let to cool
- The heated solution was separated in two 30 ml glasses one containing filter solution and one unfiltered solution
- 1ml of a starch solution containing 1 teaspoon cornstarch and 200ml distilled water was added to all the other tomato juice solutions
- Iodine tincture is then added to each of the solutions drop by drop to observer when they each change color to blue/black
When recreating the experiment in different conditions I have observed that the time the solution is affected by heat and the intensity of the heat change the amount of tincture iodine needed for the substance to change color. Also it takes less drops for the substance to change color if the tested quantity is smaller.
This experiment has clearly shown that the levels of the vitamin c in tomatoes decrease after being affected by heat. My recommendation is that if you want to eat tomatoes you should eat fresh not cooked.