How do different cooking alternatives affect the Vitamin C content in vegetables?
For this experiment, you will need:
- 12 carrots
- Stainless steel pot
- Steaming Basket
- 1 liter of water
- Distilled Water
- 6 Vacuum Packing Bags
- Vacuum electrical packer
- 2 Pipettes
- 750 milliliter Beaker
- 30 milliliters of 10% H2SO4
- 30 milliliters of 1% Starch Solution
- 100 milliliters of iodine solution
- 1 Marker
1. Wash and prepare the carrots for cooking.
2. Cut the carrots into 3cm cubes.
3. Rinse the chopped carrots in cold water thoroughly.
4. Pour 1 liter of water into the stainless steel pot, add 100 cubes of carrots into the pot of water.
5. Turn on the stove to boil the pot of carrots. Start the stopwatch once you turn on the stove.
6. Take out 30 cubes of carrots after the first 15 minutes. Leave the rest to cook in the pot. Cool the 30 cubes of carrots in the colander for 10 minutes. Seal this batch in a vacuum pack and label it as “15 Minutes Boil”
|Sample||Weight of Sample (g)||Amount of Iodine Used (ml)|
|15 Minutes Boil|
|30 Minutes Boil|
|45 Minutes Boil|
|15 Minutes Steam|
|30 Minutes Steam|
|45 Minutes Steam|
7. Another 15 minutes later, take out another 30 cubes of carrot and leave the rest in the pot. Cool the 30 cubes of carrots in the colander for 10 minutes. Seal this batch in a vacuum pack and label it as “30 Minutes Boil”
8. At the 45 minute interval, turn off the stove and remove 30 carrot cubes. Cool the 30 cubes of carrots in the colander for 10 minutes. Seal this batch in a vacuum pack and label it as “45 Minutes Boil”
9. Remove all remaining carrots from the pot.
10. Place the steaming basket over the water. Add 45 cubes of carrots into the steaming basket.
11. Repeat step 5 to 8, labeling the bags:
a. 15 Minutes Steam
b. 30 Minutes Steam
c. 45 Minutes Steam
12. Leave the bags in the refrigerator overnight.
Preparing the Vitamin C indicator
1. Place the 750 milliliter beaker onto the electronic balance and tare to set the scale to 0. Add the carrot cubes from “15 Minutes Boil”.
2. Add 400 milliliters of distilled water to the beaker.
3. Add 5 milliliters of 10% H2SO4 (sulfuric acid) using a pipette
4. Add 5 milliliters 1% starch solution to mixture using another pipette.
5. Titrate the mixture with iodine solution to a blue-black end point that lasts for at least 25 seconds
6. Record the amount of iodine solution used in the table below