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Old 12-18-2005, 12:41 PM
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For vball girl

PURPOSE

The purpose of this experiment was to determine if controlled atmosphere apple storage would affect the amount of malic acid and starch levels in apples.
I became interested in this idea when one day I bit into an apple and it was crisp, mild, smooth and tart, while a week later the same batch was grainy and had a not-so-good taste.
The information gained from this experiment may be useful for consumers and people in the apple industries.



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HYPOTHESIS
My 1st hypothesis was that the malic acid content would decrease as the storage temperature increased.
I based my 1st hypothesis on the fact that apples ripen faster in warmer temperatures and malic acid content decreases after ripening.

My 2nd hypothesis was that the starch content would decrease as the storage temperature increased.
I based my 2nd hypothesis on a quote from a fruit storage article that said controlled temperature storage “slowed the ripening process.”

My 3rd hypothesis was that the longer the apples were stored the greater the malic acid content.
I based my 3rd hypothesis on the quote “The malic acid is pure in the apple just before it is ripe, but is less afterwards.”

My 4th hypothesis was that the longer the apples were stored the greater the affect on the starch content.
I based my 4th hypothesis on storage articles about temperature and its affect on ripening and sugar/starch content.



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EXPERIMENT DESIGN
The constants in this study were:
§ Number of apples juiced
§ Amount of juice used for each test
§ Amount of water used for each test
§ Temperature of the 4º C room
§ Temperature of the 21º C room
§ Temperature of the 32º C room
§ Type of apple and harvest week
§ Number of apples used for starch test
§ Type of automatic titrater

The manipulated variables were the temperature the apples were stored at and the amount of time they were stored.
The responding variable was the amount of malic acid and starch in apples.
To measure the responding variable I used a titrater to measure the amount of malic acid and an iodine solution to measure the starch.



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MATERIALS

QUANTITY ITEM DESCRIPTION

36 Red delicious apples
3 30x46x13cm cardboard box
1 clean paring knife
1 15x46x5cm cardboard box
1 5ml. Pipetteman pipette
13 sml.pipette tips
1 250mL. Beaker
3 400mL. pipette
1 Omega Fruit & Vegetable Juicer
100mL. Iodine spray (0.5% I2)
1 0.4732 Spray bottle
1 clean plastic cutting board
1 Schotts automatic titrater
1 stir bar
1 safety glasses
1 fume hood
1 100mL. Graduated cylinder
1300mL. Distilled water
1 4º C storage room
1 21º C storage room
1 32º C storage room
1 Adult supervisor



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PROCEDURES

Time Zero
1. Set 3 apples aside for later use.
2. Put 12 apples in each of 3 smaller boxes.
3. Label one A, one B, and one C.
4. Put box A in 4º C storage room.
5. Put box B in the 21º C storage room.
6. Put box C in the 32º C storage room.
7. Cut the three apples you set aside in half horizontally.
8. Put the bottom half in the shallow cardboard box and place under fume hood. Label box in thirds A, B, and C.
9. Spray the tops of the bottom half with iodine solution.
10. Cut the top half in 1/8’s.
11. Put a beaker under spout of the juicer and push two pieces of apple into juicer.
12. Discard juice made from the pieces and put the beaker labeled A under the spout.
13. Push one piece of apple into the juicer at a time until all pieces are juiced. Empty contents inside juicer (pulp) into garbage can.
14. Take juice and using the pipette, put 10 mL of juice into a beaker and add 100 mL of distilled water.
15. Put stir bar in and put under electrode of the titrator. Insert sodium hydroxide ejector; turn the titrator and the stir bar on according to the supervisor.
16. Record malic acid and starch levels.
17. Clean juicer and supplies.
Procedures
1. Collect three apples from each room in buckets labeled A, B, and C.
2. Cut all the apples in the A bucket in half horizontally on the plastic cutting boards.
3. Put the bottom half in the shallow cardboard box and place under fume hood.
4. Spray the tops of the bottom half with iodine solution.
5. Cut the top half in 1/8’s.
6. Put a beaker under spout of the juicer and push two pieces of apple into juicer.
7. Discard juice made from the pieces and put the beaker labeled A under the spout.
8. Push one piece of apple into the juicer at a time until all pieces are juiced. Empty contents inside juicer (pulp) into garbage can.
9. Set aside for later use.
10. Repeat steps 2-10 for apple buckets B and C.
11. Take juice and using the pipette, put 10 mL of juice into a beaker and add 100 mL of distilled water.
12. Put stir bar in and put under electrode of the titrator. Insert sodium hydroxide ejector; turn the titrator and the stir bar on according to the supervisor.
13. Record malic acid and starch levels.
14. Clean juicer and supplies.




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RESULTS
The original purpose of this experiment was to determine if controlled atmosphere apple storage affects the amount of malic acid and starch in apples.

The results of the experiment were that the malic acid content decreased as the storage temperature increased and that the starch content decreased as the storage temperature increased. The malic acid and starch content both decreased over time in storage.



See my table and graph.




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CONCLUSION

My 1st hypothesis was that the malic acid content would decrease as the storage
temperature increased.

My 2nd hypothesis was that the starch content would decrease as the storage temperature increased.

My 3rd hypothesis was that the longer the apples were stored the greater the affect on the malic acid content.

My 4th hypothesis was that the longer the apples were stored the greater the affect on the starch content.

The results indicate that all hypothesizes should be accepted.
Because of the results of this experiment, I wonder if the apple the apple dehydrates in warmer climate and makes a higher concentration of sugar and malic acid.
If I were to conduct this project again I would have had more apples to test. I also would have more frequent tests like every two days instead of once a week, also I would have replicated my entire experiment.
__________________
In the begining God made heaven and the earth.And the earth was without form,and void;and the darkness was upon the face of the deep.And the spirit of God moved upon the face of the waters.And God said,"let there be light":and there was light .And God saw the light was good :and God divided the light from darkness.And God called the light day and the darkness night.And the evening and the morning were the first day.

Genesis chapter 1 verses 1-5
T_BOC

Last edited by Mad Scientist; 12-22-2005 at 06:10 AM..
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