Effect of exposure - data

9. How to show that the experimentation was carried out as reported? (Evidence) Use of photograph, audio or video recording.

10. How to organize and present the data collected? (Results)

1^st experiment

Initial pH level of orange juice samples: 3.42

Constant temperature: 8°C (inside fridge)

Elapsed Time (hours)	pH Level of Orange Juice Sample (Covered)	pH Level of Orange Juice Sample (Exposed)
0	3.42	3.42
¼	3.43	3.50
½	3.45	3.56
¾	3.49	3.61
1	3.51	3.65
1¼	3.54	3.68
1½	3.56	3.71
1¾	3.58	3.72
2	3.59	3.72
2¼	3.60	3.75
2½	3.60	3.76
2¾	3.61	3.78
3	3.63	3.82

	Initial pH level	pH level at the end of 3h	Change in pH level	Percentage of change in pH (%)
Covered sample of orange juice	3.42	3.63	+0.21	+6.14
Exposed sample of orange juice	3.42	3.82	+0.40	+11.7

2^nd experiment

Initial pH level of orange juice samples: 3.29

Constant temperature: 8°C (inside fridge)

Elapsed Time (hours)	pH Level of Orange Juice Sample (Covered)	pH Level of Orange Juice Sample (Exposed)
0	3.29	3.29
¼	3.31	3.37
½	3.35	3.42
¾	3.38	3.47
1	3.40	3.51
1¼	3.42	3.54
1½	3.45	3.58
1¾	3.46	3.61
2	3.50	3.65
2¼	3.51	3.68
2½	3.53	3.72
2¾	3.56	3.73
3	3.58	3.75

	Initial pH level	pH level at the end of 3h	Change in pH level	Percentage of change in pH (%)
Covered sample of orange juice	3.29	3.58	+0.29	+8.81
Exposed sample of orange juice	3.29	3.75	+0.46	+14.0

11. What do the data mean? (Data Analysis)

From both experiments, we can see that the pH of both samples of orange juice increase over time. However, the pH of the exposed samples of orange juice increase at a faster rate than the covered samples of orange juice. There is also a greater change (increase) in pH levels of the exposed samples of orange juice at the end of 3h compared to the covered samples. In the first experiment, the exposed sample of orange juice experienced 5.56% more increase in pH compared to the covered sample. In the second experiment, the exposed sample had 5.19% more increase in pH than the covered sample.

This increase in pH level shows the rate at which the vitamin C content in the orange juice is degrading. This shows that vitamin C degrades faster in orange juice when the juice is exposed to air. Also, since there were no other affecting factors to the change in pH level of the orange juice aside from exposure to air, and the experiment was repeated and achieved similar results, it is safe to say that it is fairly accurate.

12. What can you deduce from the discussion of your data analysis? (Conclusion)

With this set of data, I can deduce that exposure to air affects the degradation of vitamin C in orange juice. The more the exposure to air, the faster the rate of degradation of vitamin C in orange juice. This also means that the lesser the orange juice is exposed to air, the better the retention of vitamin C, therefore proving my hypothesis right.

Effect of exposure - 2nd experimental plan

I made some changes to the experimental procedure as I felt there were some things that could have been improved on.

New procedure:
Step 1: Squeeze fresh orange juice, enough to fill one whole cup.
Step 2: Take initial pH level of orange juice and record it down.
Step 3: Pour orange juice equally into 2 plastic cups.
Step 4: Immediately cover the top of 1 cup with aluminum foil and cling wrap, and leave the other cup uncovered.
Step 5: Put both cups of orange juice in the fridge.
Step 6: Leave setups inside fridge for 3 hours and record the pH level of the juice every 15 minutes with the help of the data logger and pH probe.
Step 7: Construct a table for each set of data and then plot separate graphs of pH level against time.
Step 8: Repeat entire experiment once more.

Firstly, I decided to do both setups concurrently so that the initial pH levels of both setups would be the same. Using different oranges for both setups could have resulted in different pH levels for both samples of juice. Having same initial pH level will allow the data collected to be easier to analyse, easier to observe the difference in changes in pH level of both setups.

Secondly, I decided to record the pH level every 15 minutes instead of every 30 minutes so that there will be more data recorded, allowing us to observe in more detail on how the pH level changes.

Thirdly, I decided to repeat the entire experiment once more to ensure the accuracy of my results.

Effect of exposure - 1st experimental plan

1. What do you want to find out? (Aim/Purpose/Research question)
The effect of exposure to air on the retention of vitamin C in orange juice.

2. What is the tentative explanation of your research question? (Hypothesis)
The lesser the orange juice is exposed to air, the better the retention of vitamin C.

3. In an investigation, there is only one variable to be changed. Which variable will you change in this investigation? (Independent variable)
Exposure of the orange juice.

4. All the other variables must be kept constant. What are a few important variables that will affect the results greatly? (Constant variables)
- Type of orange juice
- Amount of orange juice
- Time taken (for experiment)
- Temperature
- Material of container
- Size of container

5. What results will you measure? (Dependant variable)
The pH level of the orange juice.

6. What are the materials and apparatus that you will need to carry out the investigation? (Materials and apparatus)
- Freshly squeezed orange juice
- 2 plastic cups
- Aluminum foil
- Cling wrap
- Data logger with pH probe

7. What are the steps that you will take to carry out the investigation? (Procedure)
Step 1: Squeeze fresh orange juice, enough to fill half a cup.
Step 2: Take initial pH level of orange juice and record it down.
Step 3: Pour orange juice into a plastic cup and immediately cover the top of the cup with aluminum foil and cling wrap.
Step 4: Put the cup of orange juice in the fridge.
Step 5: Leave setup inside fridge for 3 hours and record the pH level of the juice every ½ hour with the help of the data logger and pH probe.
Step 6: Construct a table for the data and then plot a graph of pH level against time.
Step 7: Repeat step 1 and 2.
Step 8: Pour orange juice into cup and leave the top uncovered.
Step 9: Repeat steps 4-6.

8. How are data collected? (Data collection)
Data is collected with the data logger and pH probe. This device records the pH level of the orange juice at my chosen time and allows me to see the change in pH of the orange juice samples. By observing the pH change in the juice, I am then able to determine which condition best allows the retention of vitamin C, as vitamin C is ascorbic acid. The increase in pH level of the juice – both covered and not covered over time will show me how fast the vitamin C in each sample of orange juice is degrading. The orange juice sample that is covered will have less exposure to air while the sample that is not covered is constantly exposed to air throughout the entire duration of my experiment. This will then allow me to prove or disprove my hypothesis that the lesser the exposure to air, the better the retention of vitamin C in the orange juice.

Full experimental rough plan.

1st experiment: Effect of exposure to air on retention of vitamin C in orange juice.
2nd experiment: Effect of temperature on retention of vitamin C in orange juice.
3rd experiment: Effect of material of container on retention of vitamin C in orange juice.
Final concluding experiment: Best way to store orange juice for the retention of the vitamin C content.

For the 1st to the 3rd experiments, they will be individual experiments where all other factors that may affect the pH level of orange juice will be kept constant in all setups. For example, for the 1st experiment, I will make sure that both setups are kept in the same, constant temperature and only test how the exposure to air affects the degradation of vitamin C / ascorbic acid in the orange juice samples.

In the final concluding experiment, I will make use of all the data that I have collated from the first 3 experiments to form a setup that has the best potential (eg. low temp, very little exposure, glass container) to retain as much of the vitamin C content in the orange juice. I will then be able to conclude my entire Science Investigative Experiment after finding out what is the best way to store orange juice to minimise the degradation of the vitamin C content. These findings, combined, will then be useful and helpful information to people who like to drink orange juice, or drink orange juice for its nutritional content (vitamin C).

Proposal.

APPENDIX D
Science Investigative Project
Project Proposal Form
Name: Nicole Pua Kai Qian ( 24 )
Secondary: 2/10

Topic of investigation: Retention of Ascorbic Acid (Vitamin C) in Orange Juice

Observations made
I noticed that freshly squeezed orange juice left in the fridge tastes slightly more sour than the juice placed outside in room temperature for the same amount of time.
I also realised that when I left freshly squeezed orange juice uncovered and exposed in the open, it turns darker shades of orange faster as compared to the juice kept in a capped bottle or in the fridge. The orange juice that was left exposed also lost a great deal of its flavour and taste. The juice in the bottle took a longer time to change colour, and only started to turn brown after six months, losing much of its original flavour. Whereas, the juice in the fridge kept its fresh look and flavour for a much longer time.

Research Question
Does temperature affect the retention of vitamin C (ascorbic acid) in orange juice?
Does exposure [to air] affect the retention of vitamin C (ascorbic acid) in orange juice?
What is the best way to store orange juice so as to minimize the degradation of vitamin C?

Hypothesis statement
The lower the temperature, the better the retention of vitamin C.
The less exposed the orange juice is, the better the retention of vitamin C.
It is best to store orange juice without exposure to the surrounding air and in cold temperatures to minimize the degradation of vitamin C.

A short summary of research done on the area of investigation
Vitamin C, ascorbic acid, is one of the most important vitamins found in citrus juices, including orange juice. This ascorbic acid can be measured by seeing the pH level of the juice, determining how much vitamin C the juice possesses. The lower the pH level, the higher the amount of ascorbic acid/vitamin C. There are many factors that affect the vitamin C contents of citrus fruits such as oranges. Five main affecting factors are climate conditions (especially temperature), maturity state and position on tree, type of citrus fruit, type of container, and handling and storage.
As for temperature, research has shown that total available heat affects vitamin C levels. Areas with cool nights produce citrus fruits with higher vitamin C levels while hot tropical areas produce fruit with lower levels of vitamin C. Environmental conditions that increase the acidity of citrus fruits also increase vitamin C levels. Other experiments have also shown that there is a better retention of ascorbic acid in orange juice in colder temperatures. 

Oxygen in the air is the most destructive ingredient in juice causing degradation of vitamin C. One of the major sugars found in orange juice, fructose, can also cause vitamin C breakdown. The higher the fructose content, the greater the loss of vitamin C. Conversely, higher acid levels of citric and malic acids stabilize vitamin C. Orange juice must be stored at proper cool temperatures with oxygen barriers for best retention of vitamin C levels. 

Orange juice changes in colour due to oxidation, with nothing whatsoever to do with bacteria cultures. The juice is perfectly safe to drink due to the pasteurization process, but after it changes colour, it loses much of its flavour. This is due to the depletion of vitamin C/ascorbic acid in the juice, also causing a decrease in nutritional value.

Bibliography
Townsend, C. (2006, February 1). Vitamin c and citrus juices. Retrieved from http://www.ultimatecitrus.com/vitaminc.html
Chu, M. (2004, October 2). Orange juice shelf life. Retrieved from http://www.cookingforengineers.com/article/7/Orange-Juice-Shelf-Life
Abbasi, A., & Niakousari, M. (2008). Kinetics of ascorbic acid degradation in un-pasteurized Iranian lemon juice during regular storage conditions. Pakistan Journal of Biological Sciences, 11 (1028-8880). Retrieved from https://docs.google.com/viewer?a=v&q=cache:EebKuFZGuDwJ:scialert.net/pdfs/pjbs/2008/1365-1369.pdf+%22effect+of+storage+temperature%22%2BpH%2Bjuice&hl=de&gl=de&pid=bl&srcid=ADGEESgQcpIKg_bokFdpuGgv27P1beUpZ77hLsc1QQvIBaydoeJQPP7sxfQVI3AN0liSQGWNIKt5u34OhQAbLJiTGary__ybpZ9ekr45r2k7HVotBqE1l_vDXS3b0-FRJZQhpkWPrLhv&sig=AHIEtbRLEfJPZ2V9nDZNwEi_nh2EVwlaWw&pli=1
Kohler, J. (1998). The best way to store freshly made juice. Retrieved from http://www.discountjuicers.com/storingjuices.html

Brainstorming.

Possible SIP ideas

1. Does storage temperature affect the pH of juice?
--> Does temperature affect the pH level of orange juice?

• Observation: freshly squeezed cold orange juice tastes more sour than orange juice at room temperature
• Research: there is better retention of ascorbic acid in orange juice samples stored in colder temperatures (https://docs.google.com/viewer?a=v&q=cache:EebKuFZGuDwJ:scialert.net/pdfs/pjbs/2008/1365-1369.pdf+%22effect+of+storage+temperature%22%2BpH%2Bjuice&hl=de&gl=de&pid=bl&srcid=ADGEESgQcpIKg_bokFdpuGgv27P1beUpZ77hLsc1QQvIBaydoeJQPP7sxfQVI3AN0liSQGWNIKt5u34OhQAbLJiTGary__ybpZ9ekr45r2k7HVotBqE1l_vDXS3b0-FRJZQhpkWPrLhv&sig=AHIEtbRLEfJPZ2V9nDZNwEi_nh2EVwlaWw&pli=1)
• Research: colder temperatures produce citrus fruit with higher vitamin C levels = more ascorbic acid (http://www.ultimatecitrus.com/vitaminc.html)

2. Does pH level affect the germination of seeds?

• Research: seeds germinate faster and the more seeds germinate in solutions with closer to neutral pH levels

3. Which solvent is most effective in removing stains? (water, alcohol, vinegar, detergent, etc.)

4. Does light affect the rate at which foods spoil?

Narrowing down my ideas

1. I am rather interested in this topic as me and my family members enjoy drinking orange juice. The experiment can also be further expanded upon by testing other factors that affect the orange juice. It will also benefit others by informing them how to best store their orange juice.

2. It is too simple an experiment to conduct and has very little to expand on.

3. It is too simple and the complexity level is very low. It is a standard general experiment.

4. It may be too costly to carry out such an experiment as I need to use a lot of electricity and different light sources and materials.

Final choice

Does temperature affect the pH level of orange juice?

Modification of idea

What affects the pH level of orange juice is the amount of vitamin C, also known as ascorbic acid, in the juice. So, it will be temperature affecting the amount of vitamin C remaining in the orange juice. Instead of only testing the effect of temperature, I can also test the effect of exposure to air on the degradation of vitamin C in the orange juice. Other than that, the material of the container used to store the orange juice can also be tested on how it affects the retention of vitamin C in the juice. After conducting all of these three experiments on temperature, exposure and material of container, I can then do a concluding experiment with all the results of these sub-experiments to see what is the best way to store orange juice to minimize the degradation of the vitamin C content.