Effects of Different Food Minerals on the Human Body
Food minerals are required for life and good health. They consist of inorganic (compounds without carbon and hydrogen) salts and are found in the foods you eat.
In this project, you will examine the functions of different food minerals and their effect on the human body. You will learn about the deposition and growth of calcium crystals within the body and demonstrate reverse calcification of a bone. You will also look at the effect of mineral ion concentration inside and outside body cells.
Purpose: To demonstrate the effect of acids on bones.
- steak knife
- uncooked chicken leg
- 1-quart (1-liter) jar with lid
- white vinegar
- Carefully cut as much of the meat away from the chicken leg bone as possible.
- Examine the flexibility of the bone by trying to bend it with your fingers.
- Place the cleaned bone in the jar.
- Cover the bone with vinegar.
- Secure the lid on the jar (see Figure 8.1)
- After 24 hours, remove the bone from the jar and examine it for flexibility.
- Replace the bone in the vinegar.
- Examine the bone for flexibility each day for seven days.
CAUTION: Wash your hands after handling the chicken because uncooked chicken can be contaminated with salmonella bacteria.
The flexibility of the bone increases daily. At the end of the test period, the bone feels very rubbery.
During fetal development, strong fibers of protein called collagen form a matrix (pattern) for bones. The matrix is shaped like the bones but is very flexible. The matrix solidifies by a process called calcification. During this process, calcium phosphate or hydroxyapatite, Ca10(PO4)(OH)2, is deposited in the fibers of collagen and gives the bones strength and rigidity.
In this experiment, soaking the bone in vinegar leaches out the calcium compounds, resulting in reverse calcification. The rubbery bone-shaped form that results is the original collagen "mold" for the bone.
Try New Approaches
Bacteria in your mouth chemically change some of the sugars in food into acid. This acid, like vinegar, reacts with the hydroxyapatite compound in your teeth. Does body temperature speed up the decalcification reaction? Does temperature affect the speed of the reaction between the acid and the calcium compound? Repeat the experiment two times, first storing the jar containing the vinegar and bone in a refrigerator, and then using a thermos bottle of heated vinegar. Heat the vinegar to about 100°F (38°C), pour the hot liquid into the thermos bottle, add the bone, and secure the lid. Reheat the vinegar each day.
CAUTION: Wear heat-resistant oven mitts to protect your hands when pouring the hot liquid.
Make a daily comparison of the flexibility of the bones.
Design Your Own Experiment
- Can a decalcified bone resorb (absorb again) calcium? Soak the rubbery bone in a solution of 1 teaspoon (5 ml) of calcium oxide (pickling lime from the grocery) and 1 quart (1 liter) of water. Test the flexibility of the bone each day for seven days.
- Malcolm Bourne, a food scientist at Cornell University, is working on a process of putting the firmness back into cooked vegetables. He lowers the cooking temperature and adds calcium to the food. Bourne claims that the calcium molecules chemically combine with the pectin (gluey material that binds vegetable fibers together) in the vegetable. This "salt bridge" holds the vegetable molecules together, resulting in a firmer texture.
- Sodium is the major cation (positive chemical particle) in extracellular fluid (fluid outside the cell membrane). It is responsible for keeping water in the blood from entering the cells. Potassium is the major cation inside the cell, and it keeps water from leaving the cell. When the concentration of either of these ions (charged particles in solution) gets out of balance, water moves into or out of cells until a new balance is achieved. The movement of water through the cell membrane is called osmosis.
- To demonstrate the effect of an increase of sodium ions in extracellular fluids, mix 1 tablespoon (15 ml) of salt in 1 cup (250 ml) of water in a small bowl. Cut three potato slices, each about 1/4 inch (6 mm) thick. Check their flexibility by bending the slices back and forth with your fingers. Place the potato slices in the salty water (see Figure 8.2). After 15 minutes, test the flexibility of the potato slices again.
- To demonstrate the effect of an increase in minerals inside a cell, place the same potato slices in a bowl of fresh water. After 15 minutes, test the slices for flexibility as before.
Blanching is the process of cooking vegetables briefly at a high temperature to drive out gases that can cause sour tastes and smells. Blanch 1 quart (1 liter) of fresh string beans by placing them in 2 quarts (2 liters) of boiling water and keeping the water at a boil for five minutes. Remove from the heat, cool, and test their crispness by bending several beans back and forth with your fingers.
Test Bourne's blanching process by adding 1/2 teaspoon (2.5 ml) of calcium oxide (pickling lime) to 2 quarts (2 liters) of water. Heat the water to approximately 150°F (66°C). Place 1 quart (1 liter) of fresh string beans in the water for five minutes. Remove, cool, and test for crispness as before. Compare the crispness of these beans with the crispness of the beans in the first blanching process. You could repeat the Bourne process, changing the amount of calcium oxide added to the water.