Sujin Shin Orange Juice Lab Report Introduction Orange has lots of Vitamin C but when it is processed into commercial juice the amount of vitamin C decreases while sugar and other contents are added for sweet favor. If you want to intake lots of vitamin C as much as possible from orange juice, you should make fresh homemade orange juice. However, if you cannot make orange juice at home then which commercial juice is the most efficient one to buy? We know that some nutrition information includes untruth, then how to know which orange juice in the supermarket has the most vitamin C? The solution is titration. Titration is to find out the unknown concentration of one solution by reacting it with a solution of known concentration. Macid x Vacid = Mbase x Vbase is the formula for titration. Macid is the molarity of the acid, Vacid is the volume of the acid, Mbase is molarity of the base, and Vbase = volume of the base. Question Which orange juice has the most vitamin C? And how much is the difference between vitamin C of commercial orange juice and fresh homemade orange juice? Does amount of vitamin C determine the taste? Hypothesis Fresh homemade orange juice will absolutely have the most vitamin C in it. The amount of vitamin C will makes juice taste more sour. And there will be only a little difference between amount of vitamin C in commercial juice and homemade juice. Materials 2% Lugol s iodine solution, water, funnel, 50mL cylinder, 400mL beaker, stirrer, big amber glass bottle, permanent marker, masking tape, hot plate, spoon, light plastic tray, scale, 1000mL beaker, glass jar, mortar, pestle, 50mL buret, ring stand, buret clamp, 50mL Erlenmeyer flask, three oranges, gauze swabs, five different kinds of commercial orange juice Procedure 1. Pour 30mL of Lugol s solution into 500mL cylinder. 2. Measure 300mL of water in 400mL beaker and pour it in the cylinder. 3. Carefully pour the solution into an amber glass bottle using funnel. 4. Label the bottle with permanent marker and masking tape. 5. Heat 200mL water in a beaker on hot plate. 6. Measure 1.00g of starch using scale. 7. Add measured starch when the water is near boiling. 8. Stir and dissolve starch in the water while the water boiling. 9. Pour about 150mL of cold water in 1L beaker.
10. Turn off the hotplate and put the beaker that has starch solution in 1L. Be careful that the two fluids are not mixed. 11. When the starch solution is cool, pour it into glass jar and label it. 12. Crush a vitamin C tablet with a mortar and a pestle. 13. Pour 250mL of water into 500mL graduated cylinder and add 250mg of vitamin C tablet in it.
14. Set up the 50mL buret on the ring stand. 15. Measure 20mL of vitamin C standard solution with 50mL cylinder and pour it in the 50mL Erlenmeyer flask. 16. Add 10 drops of starch solution to the fluid in the Erlenmeyer flask. 17. Place the Erlenmeyer flask right under the buret. 18. Make sure the bottom of the buret is closed and fill the buret with iodine solution using funnel. Fill somewhere between the 5mL and 35mL marks on the buret. 19. Record the initial level of the iodine solution in the buret. 20. Turn the red stopper of the buret slowly until one drop of the iodine solution comes out. Then close the buret again. 21. Swirl the flask and mix the iodine solution after each drop is added. 22. Continue doing 19-21 until a blue-black color shows up on the vitamin C standard solution. Titration is finished at this point. 23. Record the final level of the iodine solution remaining in the buret. 24. Do titration again at least twice. 25. Use the juicer and extract orange from at least three oranges. 26. Titrate the fresh-squeezed orange juice in the same way above but do not add starch indicator solution. Use gauze swab when you measure 20mL of it. Don t forget to record initial and final level of iodine solution on the buret. 27. Titrate the other five kinds of orange juice as well. 28. Calculate the average amount of iodine needed to titrate 20mL for each juice. 29. Calculate the amount of vitamin c in the samples using following equation: VitaminC2=Iodine2 VitaminC1/ Iodine1 30. Show commercial orange juice and ask which one might tastes the best they expect in order to 10 people 31. Blind test them giving the five different kinds of orange See titration process here
juice and ask which tasted the best, second best least best. Results Titration results Sample Initial level (ml) Final level (ml) Amount of iodine used (ml) Vitamin C tablet 18.6 18.8 0.2 18.8 19.05 0.25 19.05 19.3 0.25 Home-made Orange Juice 26.0 29.6 3.6 29.6 31.9 2.3 31.9 35.6 3.6 35.6 39.3 3.7 Sunkist Gold 23.2 25.3 2.1 19.3 21.4 2.1 21.4 23.2 1.8 Nong Fu Guo Tian 25.8 27.1 1.3 27.1 28.8 1.7 30.9 32.5 1.6 17.5 Orange 20.8 22.2 1.4 17.9 19.3 1.4 19.3 20.8 1.4 Mr. Juicy 27.0 27.8 0.8 27.8 28.7 0.9 28.8 29.8 1.0 Wei Quan Mei Ri 20.9 22.4 1.9 22.4 24.2 1.8 24.2 26.0 1.8 Calculation Result Sample Average amount of iodine used (ml) Amount of vitamin C (mg) Homemade Fresh Orange Juice 3.30 0.003036
Sunkist Gold 2.00 0.00184 Nong Fu Guo Tian 1.53 0.0014076 17.5 Orange 1.43 0.0013156 Mr. Juicy 0.90 0.000828 Wei Quan Mei Ri 1.83 0.0016836 Which orange juice will taste the best you expect 1st best 2nd best 3rd best 4th best 5th best 17.5 Orange 2 3 0 3 2 Mr. Juicy 1 2 4 3 0 NongFuGuoTian 0 1 1 2 6 Sunkist Gold 7 1 1 0 1 WeiQuanMeiRi 0 3 4 2 1 Which orange juice tasted the best 1st best 2nd best 3rd best 4th best 5th best 17.5 Orange 1 1 3 3 2 Mr. Juicy 3 3 2 1 1 NongFuGuoTian 1 2 1 2 3 Sunkist Gold 3 1 1 2 3 WeiQuanMeiRi 1 3 5 1 0 Analysis According to the tables above, obviously, fresh orange juice has the most vitamin C. It has 0.003036 mg of vitamin C which is triple each amounts of the other juice. Sunkist Gold has the second most vitamin C, 0.00184 mg. Wei Quan Mei Ri has the third most, 17.5 Orange has the fourth most, and Mr. Juicy had the least amount of vitamin C between these five. Majority of people agreed that Sunkist Gold will taste the best. Pretty many people told Sunkist Gold tasted bad because it was bitter. Otherwise there were some people that told Sunkist Gold tasted the best. Those people who thought Sunkist Gold is best already recognized that it is Sunkist Gold. Mr. Juicy had many good comments from people, however, it contained the least vitamin C between the six orange juice. It is almost 1/4 of vitamin C in homemade orange juice. The other three orange juice got less expectation than these two commercial juice but in blind testing people seemed to have better taste than their expectations. Nevertheless it can't be determined as well because it seems to depends on personally a lot.
Conclusion Drinking fresh squeezed homemade orange juice is the best way to intake the most vitamin C from orange juice. It contains twice more vitamin C of other commercial orange juice. Sometimes even triple more. However if you just want to buy the orange juice that has the most vitamin C from supermarket, Sunkist Gold is the best one. It tastes little bitter at the end people say but it still contains lots of vitamin. Mr. Juicy tastes sweet but it has the least vitamin C and more sugar than others. Therefore amounts of vitamin C do determine the taste of orange juice. More vitamin C, more sour and stronger. Less vitamin C, blander and more water-like(because it's in low concentration). And lastly, determining the taste with only the cover or the colors of orange juice is no good. There could be good tasted one that might look not tastable in looking. Reference Science buddy- which orange juice has the most vitamin C? (http://www.sciencebuddies.org/science-fair-projects/project_ideas/chem_p044.shtml) Determination of Vitamin C Concentration by Titration- University of Canterbury Wikipedia- Titration