Using Dehydration to Preserve Food

When planning for a long mission to the Marsville colony, scientists will have to consider methods of taking enough food for the long journey. Room for storage on the spacecraft will be limited. Also, the trip to Mars will last for many months and it will not be possible to carry fresh food. Methods of preparing food for this mission must be examined. Dehydrated food takes up very little space and lasts for a long period of time.

Purpose

• To demonstrate that dehydrated food takes up less space than fresh food.
• To examine methods of dehydrating foods to take on a long space mission.

Materials and Equipment

• 2 apples (per group)
• Sharp knife
• Cutting board
• Thin string or heavy thread
• Needle
• Scissors
• Hanger
• Balance scale
• Food dehydrator (optional)
• Other types of fruit (optional activity)
• Paper towel (optional activity)
• Pie plate (optional activity)
• Cheesecloth (optional activity)

Method #1

1. Work with a small team for this activity. Bring the apples from home if possible. You can use apples that are not suitable for eating anymore.
2. Weigh one apple and record the results. Leave this apple in a cool place during the experiment.
3. Peel and cut another apple into 6 sections.
4. Thread a needle with a piece of thin string or heavy thread about 20 centimetres long. Pierce an apple piece with the threaded needle and attach the string to the apple. Attach the other end of the string to the hanger. Repeat for all the apple pieces.
5. Make sure there is enough room around the apple pieces for good air circulation. Place the hanger in a well ventilated area to allow the apple pieces to dry.
6. Check the experiment every day for 3-4 days.
7. After this time, place the whole apple beside the dried apple slices and compare the two "apples".
8. Weigh the whole apple and apple slices after several days and record the data.
9. Compare the data in a graphical format.

Method #2 - Conduct on a sunny day!

1. Wash, core and slice apples, pears, bananas or peaches.
2. Pat each piece of fruit dry with a paper towel and lay the pieces on the pan so they do not touch.
3. Cover the pan with a layer of cheesecloth and leave in a location that receives sunshine for most of the day. Move the pan during the day if necessary.
4. Check the fruit every few hours. They should be ready in eight hours. The sun will have killed the bacteria in the fruit and removed the moisture. The fruit will keep indefinitely.
5. Try the same activity but use a microwave oven. Taste test the results and record the findings of the group.
6. Compare the data in a graphical format.

Observations/Results

• Record your observations.
• Post your results in your Team Blog.

Questions

• Why is there a difference in the mass of the apples?
• How long will the dried apples from Method #1 last without going bad?
• How can this information be used for the design of the colony?

Other Activities

• If someone has a food dehydrator, repeat the experiment but place the apple or fruit slices in the machine instead of leaving them to dry in the air. Note the difference in the consistency of the fruit preserved in this manner. Survey the class to determine which method gives the best results.
• Challenge other participants in the Canadian National Marsville programme to come up with alternate methods of preserving food for the Mars colony.