Real world vitamin c concentration and total acidity in orange juice and grapefruit juice
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Real World: Vitamin C Concentration and Total Acidity in Orange Juice and Grapefruit Juice. By: Kate Steinle , Jess Reese, Richard Janosky and Korvin Mercer. Importance of Vitamin C. Cannot be stored in body, needs to be replenished regularly

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

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Real world vitamin c concentration and total acidity in orange juice and grapefruit juice

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

By: Kate Steinle, Jess Reese, Richard Janosky and Korvin Mercer


Importance of vitamin c

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


Measuring the vitamin c content of foods and fruit juices

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


  • Measuring the vitamin c content of foods and fruit juices cont d

    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


    Calculations

    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


    Results

    Results


    Conclusion

    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


    Iodine titration

    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


    Results1

    Results


    Results continued

    Results Continued


    Conclusion1

    Conclusion

    • Fresh squeezed orange juice has the highest Vitamin C concentration

    • Fresh squeezed juices have a higher vitamin C concentration than juice from concentrate


    Determination of the total acidity in orange juice

    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


    Determination of the total acidity in orange juice cont d

    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


    Comparing experiments

    Comparing Experiments

    • All experiments showed that freshly squeezed juices had more vitamin C

    • Two of three: orange juice had most


    Comparing vitamin c from dcpip and iodine titrations

    Comparing Vitamin C from DCPIP and Iodine Titrations


    Bibliography

    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


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