Real World: Vitamin C Concentration and Total Acidity in Orange Juice and Grapefruit Juice

1. Real World:Vitamin C Concentration and Total Acidity in Orange Juice and Grapefruit Juice By: Kate Steinle, Jess Reese, Richard Janosky and Korvin Mercer

2. Importance of Vitamin C Cannot be stored in body, needs to be replenished regularly Promotes healthy cell development, normal tissue growth and repair, and helps in absorption of calcium. Vitamin C is lost in foods easily, so it is best to eat fruits and vegetables in raw form Scurvy -disease caused by lack of vitamin C It�s an antioxidant, helps protect body against contaminants

3. Measuring the Vitamin C content of foods and fruit juices DCPIP(2,6 � dichlorophenol-indophenol) can be used as an indicator for ascorbic acid. DCPIP turns clear when it is oxidized by the orange juice. When there is excess DCPIP, it no longer turns clear and dyes the sample purple. 1% DCPIP solution added to juice until color change occurred The amount of DCPIP added was recorded Taking into account the amount of vitamin C there should be in the juice based on daily value, the theoretical and actual values of Vitamin C were calculated

4. Measuring the Vitamin C content of foods and fruit juices (cont�d) Theoretical Total volume of container Amount of servings 100% daily value Volume of juice used Experimental 1% DCPIP solution mL of DCPIP added, gives grams of DCPIP 1:1 mol ratio

5. Calculations Theoretical: Theoretical grams of Vitamin C X Servings= grams vitamin C per bottle Fresh Squeezed Orange Juice: 0.124g X 2 servings=0.248g vitamin C per bottle Experimental: Total volume in bottle/volume added=theoretical grams vitamin C/grams vitamin C in sample Fresh Squeezed Orange Juice: 473mL/10.31mL=0.248g/x X=0.0055g

6. Results

7. Conclusion In all juices, there was almost double the theoretical amount of vitamin C Reason? Companies want to make sure that they have at least the amount of vitamin C in their juice that they claim Too much is not a bad thing

8. Iodine Titration 25mL of juice samples were titrated with an iodine solution until the endpoint was reached. A 1% starch indicator was used as the indicator The amount of vitamin C was calculated and compared based on daily values for each juice

9. Results

10. Results Continued

11. Conclusion Fresh squeezed orange juice has the highest Vitamin C concentration Fresh squeezed juices have a higher vitamin C concentration than juice from concentrate

12. Determination of the Total Acidity in Orange Juice 3 samples of each juice were titrated with standardized NaOH pH level were measured each addition of NaOH Calibration curve were made pH calculated for each juice Used the curve to estimate equivalence point Another way: change in volume vs. pH

18. Determination of the Total Acidity in Orange Juice (cont�d) Freshly squeezed juices had a higher pH than the juices from concentrate Grapefruit juice more exaggerated relationship Freshly squeezed juices are more acidic

19. Comparing Experiments All experiments showed that freshly squeezed juices had more vitamin C Two of three: orange juice had most

20. Comparing Vitamin C from DCPIP and Iodine Titrations

21. Bibliography http://www.fitnesshealthzone.com/vitamins-supplements/importance-of-vitamin-c/ http://www.practicalbiology.org/areas/advanced/health-and-disease/whats-in-our-food/measuring-the-vitamin-c-content-of-foods-and-fruit-juices,53,EXP.html http://en.wikipedia.org/wiki/Dichlorophenolindophenol http://www.google.com/#sclient=psy&hl=en&q=Determination+of+the+Total+Acidity+in+Orange+Juice&aq=f&aqi=&aql=&oq=&gs_rfai=&pbx=1&fp=fae64975a117d0cd