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