In our complex world, food products have to be shipped for long distances and/or stored for periods of time. It would be difficult to transport and store most kinds of food without using preservative additives.
In this project, you will have the opportunity to test the effectiveness of calcium propionate, a food additive that inhibits mold growth in bread. The effect of this additive in different types of bread as well as the effect of temperature on the preservative will be determined. You will also analyze other methods of preserving food.
Purpose: To determine how effective the food additive calcium propionate is in inhibiting the molding of bread.
- Paper towels
- 6 plastic 1-gallon (4-liter) size resealable bags
- 6 slices of white bread with calcium propionate
- 6 slices of white bread without calcium propionate or any other preservatives
- Marking pen
- Masking tape
- Magnifying lens (handheld type)
CAUTION: Do not do this project if you are allergic to mold.
- Moisten one paper towel with water and lay it inside one plastic bag.
- Place one slice of bread with calcium propionate and one without side by side on top of the moistened paper towel inside the bag.
- Zip the plastic bag closed.
- Use the marking pen and masking tape to label the slices of bread with and without calcium propionate. Place the label on the outside of the bag above the indicated slice of bread.
- Repeat the procedure (steps 1 through 4) preparing five additional bags with two slices of bread, one slice of bread with calcium propionate and one without, inside each bag. Note: Six bags is not a significant number, but it does provide enough samples to verify your results.
- Keep the six bags of bread closed and at room temperature.
- Examine the slices each day with the magnifying lens.
- Continue observing the bread for two weeks or until every slice has become moldy. Record the length of time required for each slice to mold. Discard the unopened bags.
- Given enough time, all of the bread slices become moldy. However, the slices with calcium propionate mold more slowly (see Figure 23.1).
Food additives are natural and synthetic chemicals added to food to supply nutrients, to enhance color, flavor, or texture, and/or to prevent or delay spoilage. Spoilage is the ruining of food as a result of chemical changes often owing to the presence of organisms such as fungi and microbes. A food preservative is a food additive, such as calcium propionate, used to maintain freshness and extend the shelf life of package food. Organisms that spoil food are fussy about their diet, and different species (group of similar organisms) can be found on specific foods.
Calcium propionate is one of the food additives on the U. S. Food and Drug Administration's GRAS ("Generally Recognized As Safe") list. At low concentrations, it is considered harmless to humans but inhibits the reproduction and growth of mold. The addition of calcium propionate to bread allows the product to be stored for longer periods of time.
Calcium propionate is a preferred preservative for bread because it retards the rapid growth of bread mold, increases the content of calcium, and avoids the possibility of decreasing gas formation during baking, thus allowing the bread to rise normally.