P ROBLEM Which kind of orange juice, frozen, bottled, or freshly squeezed, contains the most amount of vitamin C?
B ACKGROUND INFORMATION Orange juice is a good source of vitamin C and potassium Vitamin C is necessary for normal growth and development The process of concentrating OJ results in a slight loss of vitamin C Frozen orange juice is about 3x more concentrated than regular orange juice The original amount of oxygen and carbon dioxide in a can of orange juice changes over time. Some bottled juice may be fresher than others, and therefore may contain different amounts of vitamin C. Redox titration is a common method of determining the amount of vitamin C in a substance, represented by the formula: I 2 + starch (C 6 H 10 O 5 ) = starch-iodine complex.
H YPOTHESIS If the amount of vitamin C in different samples of orange juice (bottled, frozen, and freshly squeezed) was measured by using a starch-iodine indicator, then the frozen orange juice would contain the most amount of vitamin C.
M ATERIALS freshly squeezed orange juice bottled orange juice frozen orange juice three 50.0 mL beakers one 300. mL beaker one 1.00 L beaker medicine dropper stirring rod one 500. mg vitamin C tablet mortar and pestle goggles apron gloves 2.00 grams of corn starch distilled water bunsen burner wired gauze tripod 1.00 mL of tincture of iodine lighter paper pencil
P ROCEDURE Make the starch-iodine solution by filling a 300. mL beaker with 200. mL of cold distilled water Add 2.00 grams of corn starch to the 200. mL of distilled water Bring mixture to a full boil using a bunsen burner (making the starch solution) Fill a liter beaker with water Add 8.00 mL of the starch solution and 1 mL of tincture of iodine to the 1 liter beaker of water, which completes the making of the vitamin C indicator (will become a dark blue color) Stir gently Pour 15.0 mL of this indicator into a 50.0 mL beaker Use a medicine dropper to obtain a sample of the freshly squeezed orange juice Add this sample drop by drop to the beaker of the vitamin C indicator Gently swirl Continue to add the freshly squeezed orange juice, drop by drop, to the vitamin C indicator until the indicator turns from blue to colorless *make sure to swirl gently after each drop*
CONTINUED … Record the amount of drops it took to for the freshly squeezed orange juice to turn the vitamin C indicator colorless Repeat steps 6-12 for four more trials with the freshly squeezed orange juice Repeat steps 6-13 with the frozen orange juice and then the bottled orange juice Record Results (number of drops) Repeat steps 6-12 for the distilled water (note: only one trial is done with this control) Obtain a mortar and pestle Completely crush a 500. mg vitamin C tablet using the mortar and pestle Mix this crushed tablet with 100. mL of distilled water Fill a 50.0 mL beaker with 15.0 mL of the vitamin C indicator Add the tablet and water mixture to the indicator drop by drop until the indicator turns from blue to colorless Record Results (number of drops)
V ARIABLES independent variable : type of orange juice (freshly squeezed, frozen, and bottled) dependent variable : amount of vitamin C in each sample of orange juice, expressed by the amount of drops it takes to titrate the vitamin C indicator (shown by a color change) controls positive: vitamin C tablet negative: distilled water constants : procedural technique, amount of orange juice tested for each trial, same vitamin C indicator, place where the project was conducted
D ATA /R ESULTS ( IN NUMBER OF DROPS ) Trial 1Trial 2Trial 3Trial 4Trial 5AVGStddevCI bottled orange juice50.048.054.055.053.052.02.922.56 frozen orange juice12.010.012.011.012.011.40.8940.784 freshly squeezed orange juice14.015.013.015.013.014.01.000.877 Trial 1Trial 2Trial 3Trial 4Trial 5 500mg tablet with 100ml water44400 distilled water 100 drops and nothing happened Controls
TT EST R ESULTS fresh sqbottled 14 50 15 48 13 54 15 55 13 53 3.2E-09 bottledfrozen 50 12 48 10 54 12 55 11 53 12 1.8E-09 frozenfresh sq 12 14 10 15 12 13 11 15 12 13 0.0025 All results are under.05, meaning there is a significant difference between all three of the samples of orange juice
C ONCLUSION The purpose of this experiment was to test whether there were varying amounts of vitamin C in different kinds of orange juice. The experiment concluded that frozen orange juice contained the most vitamin C (1.67 mg/mL), with freshly squeezed orange juice close behind, but with bottled orange juice trailing by a significant amount. These results supported the hypothesis of the experiment. Frozen and freshly squeezed orange juices are more beneficial to humans than bottled orange juice is because those juices actually satisfy the daily requirement of vitamin C per day, which is 60 mg.
I F THIS EXPERIMENT WAS TO BE DONE AGAIN … Changes to be Made Using more kinds of orange juice other than just frozen, bottled, and freshly squeezed and more brands of each. Conducting more trials to ensure accuracy and having all testing done on the same day in the same environment. Use a more accurate method, other than a dropper, to obtain the correct amount of orange juice for each trial. Sources of Error The different orange juice samples were stored and handled before being used for this experiment and the age and conditions of the products before coming into possession for the experiment are not known.
W ORKS C ITED Boyd, J., & Peterson, G. (2010). Quality of Canned Orange Juice. Industrial and Engineering Chemistry, 37 (4), 370-373. Dolson, L. (2010). What You Need to Know about Complex Carbohydrates. Retrieved October 6, 2010, from About.com website: http://lowcarbdiets.about.com/ od/ nutrition/ a/ starch.htm http://lowcarbdiets.about.com/ od/ nutrition/ a/ starch.htm Helmenstine, A. M. (2010). Vitamin C Determination by Iodine Titration. Retrieved October 7, 2010, from About.com website: http://chemistry.about.com/ od/ demonstrationsexperiments/ ss/ vitctitration.htmhttp://chemistry.about.com/ od/ demonstrationsexperiments/ ss/ vitctitration.htm Medline Plus. (2009). Vitamin C. Retrieved October 6, 2010, from U.S. Department of Health and Human Services website: http://www.nlm.nih.gov/ medlineplus/ ency/ article/ 002404.htmhttp://www.nlm.nih.gov/ medlineplus/ ency/ article/ 002404.htm Obikoya, D. G. (2010). Iodine Information. Retrieved October 21, 2010, from Seacra Enterprises, Inc website: http://www.vitamins-nutrition.org/ vitamins/ iodine.html http://www.vitamins-nutrition.org/ vitamins/ iodine.html Practically Edible. (2010). Frozen Orange Juice Concentrate. Retrieved October 21, 2010, from http://www.practicallyedible.com/ edible.nsf/ pages/ frozenorangejuiceconcentrate http://www.practicallyedible.com/ edible.nsf/ pages/ frozenorangejuiceconcentrate Rushin, W. (2008). Chemical Analysis by Redox Titration. Retrieved October 19, 2010, from Cary Academy website: http://chem.lapeer.org/ Chem2Docs/ RedoxTitration.htmlhttp://chem.lapeer.org/ Chem2Docs/ RedoxTitration.html Shilton, N., & Nally, P. (2001, October 6). The Last Word. New Scientist, (2311). Retrieved from http://www.newscientist.com/ article/ mg17223116.600-the-last-word.html http://www.newscientist.com/ article/ mg17223116.600-the-last-word.html University of Canterbury. (2007). Determination of Vitamin C by Redox Titration with Iodine. Retrieved October 20, 2010, from http://www.outreach.canterbury.ac.nz/ chemistry/ vitamin_C_iodine.shtmlhttp://www.outreach.canterbury.ac.nz/ chemistry/ vitamin_C_iodine.shtml Clark, N. (1999, June 26). Vitamin C, Supplements and Simple Foods. Rowing News, 6 (10), 6. Retrieved from http://books.google.com/ books?id=SU0EAAAAMBAJ&pg=PT5&dq=vitamin+c+in+orange+juice&hl=en&ei=- WeuTMGlPML98Aa4s6zTBA&sa=X&oi=book_result&ct=result&resnum=3&ved=0CEEQ6AEwAg#v=onepage &q=vitamin%20c%20in%20orange%20juice&f=false http://books.google.com/ books?id=SU0EAAAAMBAJ&pg=PT5&dq=vitamin+c+in+orange+juice&hl=en&ei=- WeuTMGlPML98Aa4s6zTBA&sa=X&oi=book_result&ct=result&resnum=3&ved=0CEEQ6AEwAg#v=onepage &q=vitamin%20c%20in%20orange%20juice&f=false Ronzio, R. A. (2003). Orange Juice. In Nutrition and Good Health (2nd ed., p. 478). Retrieved from http://books.google.com/ books?id=1bzCYeHoJ8sC&pg=PA478&dq=orange+juice+vitamin+c&hl=en&ei=UlSuT JhAoL78Aa2mMmaCw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CEUQ6AEwAg#v=onepage&q=or ange%20juice%20vitamin%20c&f=false http://books.google.com/ books?id=1bzCYeHoJ8sC&pg=PA478&dq=orange+juice+vitamin+c&hl=en&ei=UlSuT JhAoL78Aa2mMmaCw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CEUQ6AEwAg#v=onepage&q=or ange%20juice%20vitamin%20c&f=false