I "Can" Not Eat My Vegetables
by Lauren T.
1st Place - Chemistry

Question: Will canned, fresh, or frozen vegetables have the most acidity and therefore create the most gas?

Research: First, I did research on the two most common methods of preserving vegetables which are freezing and canning. All vegetables have enzymes that need to be destroyed or slowed in order to preserve the vegetables. You must heat them hot enough to kill the enzymes or freeze them to make the enzyme inactive. The quality and nutritional value go down in canned food after processing and sometimes chemicals are added. I also found out that vegetables chosen for freezing and canning can be picked at peak ripeness and fresh vegetables are often picked early because of shipping and trucking.

I also did research on vegetables to learn which types are more acidic than others. I learned that most vegetables are low in acidity. I did learn that white (ex: cauliflower) and green (ex: beans) vegetables are more acidic, especially dark green, leafy vegetables (ex: spinach)

Hypothesis: Canned food will have the most acidity and therefore produce the most gas.

Procedures:
1. I will use 4 vegetables (corn, spinach, carrots, and green beans) in frozen, canned, and fresh forms.
2. I will blend the vegetables into a liquid by adding distilled water.
3. I will put 1 cup of the liquid in a bottle.
4. I will add 3 tablespoons of vinegar.
5. The bottle will sit for 30 minutes to blend.
6. I will then put a balloon filled with baking soda in it and put  it on top of the bottle.
7. When the baking soda is added and I shake the bottle, the gas begins to fill the balloon.
8. I will measure the circumference of the balloon.
9. I will record the measurements on a data sheet.

Materials: 1 package frozen green beans, 1 package frozen carrots, 1 package frozen corn, 1 package frozen spinach, 1 can of green beans, 1 can of carrots, 1 can of corn, 1 can of spinach, fresh green beans, fresh corn, fresh carrots, fresh spinach, 12 plastic bottles, 12 balloons, blender, note pad, camera, funnel, measuring cups, distilled water, white vinegar, baking soda, measuring tape

Analysis: My experiment was to find out if processed vegetables had more acidity and therefore created more gas. The results of my experiment showed that canned vegetables created the most carbon dioxide gas. The average circumference for the canned vegetables I used was 12.03. The results of fresh vegetables and frozen vegetables were very similar with circumferences of 10.00 and 10.44. The small amount of salt that is used in the canning process produced more gas in my experiment. Salt is a form of sodium and baking soda is sodium bicarbonate. The two chemicals combined produced the bigger reaction. I found that green, leafy vegetables (spinach in my experiment) have a higher acidity level that most vegetables. In performing my experiment, I learned that my hypothesis was correct , that canned vegetables would create more gas.

Discovery: In this experiment, I learned that adding baking soda to the vegetable/vinegar mixture is creating a chemical reaction that produces salt, water and carbon dioxide. The salt that is produced is called sodium acetate. The carbon dioxide is the gas that is produced and small bubbles form.

I learned that most vegetables have low acidity and are called alkalizing. Of the vegetables I used, carrots and corn are considered alkalizing and green beans and spinach have a higher acidity. I also learned in my experiment that vegetables that have enzymes that are killed have a higher acidity level. When foods are canned, it kills the enzymes, while frozen foods freeze the enzymes. Lastly, I learned that spinach is the worst smelling and looking vegetable in the world when liquefied and when vinegar is added.

Bibliography:
Canning vegetables - http://msucares.com/pubs/publications/p1540.html
Eating well - http://www.eatingwell.com/health/qanda/fresh_vs_frozen.html
What you need to know about gas - http://digestive.niddk.nih.gov/ddiseases/pubs/gas.ez
Classifying the acidification potential of foods -
http://www.ph-ion.com/index.asp?PageAction=Custom&ID=15