• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14

Analysing the vitamin C content in different fruit juices

Extracts from this document...

Introduction

Title : The Vitamin C Content in Fruit Juices Name : Yii Seng Ong Date : 28 August 2011 Class : 12M15 Student ID : 2011200378 Name of lecturer : Madam Ida Muryany binti Md. Yasin Objective 1. To determine and compare the concentration of vitamin C in different kind of fruit juices 2. To determine and compare the concentration of vitamin C in freshly prepared fruit juices and carton fruit juices Introduction 1. Vitamin C Vitamin C or also can be known as ascorbic acid is the elonic form of 3-oxo-L-gulofuranolactone. It can be synthesized from glucose or extracted from other plant sources such as blackcurrants, rose hips or citrus fruits. The empirical formula for vitamin C is C6H8O6. Other than that, the molecular weight for ascorbic acid is 176.1. Its melting point is about 190°C( with decomposition). The appearance is white to slightly yellowish crystalline powder. It is practically odourless, with a strong acidic property and a sour taste. Figure 1 : 2D structure of vitamin C Figure 2 : 3D structure of vitamin C Generally, vitamins are a group of complex organic compounds which play an essential role in animal metabolic process but which the animal cannot synthesis. Vitamins do not provide energy however, in their absence the animal develops certain deficiency diseases or other abnormal conditions. Vitamins together with proteins, carbohydrates, fats and mineral salts are essential components of the food of animals. Certain animals can synthesis certain vitamins. All animals which need vitamin D can synthesis it from ergosterol in the presence of UV light. With the exception of vitamin D, human body cannot make its own vitamins and some cannot be stored. Therefore, one must obtain vitamins from a food on a daily basis. A person’s diet must provide all the necessary vitamins. Vitamin C is a water-soluble vitamin, meaning human’s body does not store it. We get what we need, instead, from food. ...read more.

Middle

8. The results are tabulated in Table 1. 9. A graph (Graph 1) of volume of vitamin C solution needed to decolourise DCPIP solution against concentration of vitamin C solution used( standard curve graph of vitamin C) is plotted. 1. To determine vitamin C content of freshly prepared fruit juices and carton fruit juices 1. Oranges, limes and lemons are cut and squeezed into 3 separate beakers which are labeled correctly. 2. 0.5ml of DCPIP solution is placed into a boiling tube using a syringe. 3. 3ml of freshly prepared lime juice is sucked into another syringe and added drop by drop into the DCPIP solution. 4. The mixture is shaked gently while lime juice is added continuously until the blue DCPIP solution is decolourised. The volume of lime juice used is recorded. 5. Steps 1 to 4 are repeated to obtain an average volume of lime juice used. 6. Steps 1 to 5 are then repeated using freshly prepared orange juice, freshly prepared lemon juice, carton lime juice, carton orange juice and carton lemon juice. 7. The results are tabulated in Table 2 for fresh fruit juices and in Table 3 for carton fruit juices. 8. The concentration of vitamin C in each sample of fruit juice ( 6 samples) are calculated using the formula below. Volume of fruit juice required to = k decolourise DCPIP solution concentration of vitamin C in fruit juice while k = constant 1. The concentration of vitamin C in each sample that is calculated are also tabulated in the same table. Results A) Concentration of vitamin C solution (g/100ml) Volume of vitamin C solution used to decolourise DCPIP solution (ml) Trial 1 Trial 2 Trial 3 Average 1.000 0.4 0.3 0.2 0.3 0.750 0.6 0.5 0.7 0.6 0.500 0.8 0.8 0.8 0.8 0.250 0.9 1.1 1.0 1.0 0.125 1.1 1.2 1.0 1.1 Table 1 Graph 1: Graph of volume of vitamin C solution needed to decolourise DCPIP solution against concentration of vitamin C solution used V = ...read more.

Conclusion

To ensure the reliability of results, each experiment should be repeated at least twice. The average value of volume of each fruit juice or vitamin C solution is calculated by dividing the sum of all the reading for that particular fruit juice with the number of readings taken. By repeating the same procedure, random errors such as parallax error can be minimized and at the same time, the vitamin C content of each fruit juice can be determined more accurately and may be closer to the theoretical value. Safety precautions 1. Care should be taken while cutting the fresh fruits. During the extraction of juices from the fruits, fruits should not be pounded to hard. It is because the heat produced will destroy part of the vitamin C in the juices. 2. The fruit juices should not be prepared a day earlier before the experiment or exposed to the air for a day because the vitamin C in fruits is easily destroyed by oxidation. 3. Care should be taken not to shake the tube vigorously while the vitamin C and fruit juices are added. This is because the oxygen from the atmosphere will oxidize the DCPIP solution to become blue again. If this happens, more fruit juice is needed to reduce the DCPIP solution. Therefore, the actual vitamin C content in fruit juice cannot be determined accurately. 4. In order to prevent confusion, all the beakers used should be labeled with the name of fruit juice contained. This is due to the fact that colour and smell of the lime juice and lemon juice are quite similar. Conclusion The lower the volume of fruit juice used to decolourise the DCPIP solution, the higher the concentration of vitamin C in the fruit juice. 1. The fresh orange juice has the highest concentration of vitamin C among the fruit juices tested. 2. Freshly prepared fruit juice has higher concentration of vitamin C compared to carton fruit juice. Hypothesis is accepted. Reference 1. http://www.umm.edu/altmed/articles/vitamin-c-000339.htm 2. http://www.beta-glucan-info.com/vitaminchistory.htm, Beta Force The Only Answer, Unknown author. 3. http://www.coursework.info/ ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

5 star(s)

*****
A very detailed account of the investigation written in a concise style. A clear understanding of background theory demonstrated with A level terminology used throughout. Data presentation and analysis is of a high standard.

Marked by teacher Adam Roberts 17/09/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Aim: To investigate the effect of cooking on vitamin C content in orange

    3. Use the same dropper throughout the experiment. 4. The dropper should be washed thoroughly. 5. The boiled orange juice should be cooled down. 6. The boiling of orange juice should be carefully monitored to avoid too much evaporation of water. Results: The table showing the results of the DCPIP test for the orange juice with different treatments: Sample No.

  2. To investigate how temperature affects the concentration of vitamin C in orange juice (specifically ...

    I heated solutions of orange juice to 41, 51 and 61 degrees centigrade. Then with two repeats for a higher accuracy, I measured the amount of DCPIP needed to make each solution react and turn purply brown. The real deal (Actual Experiment): As the preliminary results had taken too much

  1. Qualitative tests for carbohydrates

    It went blue under the Benedict's test which is negative, and no visual change under the Bial's test and the iodine test. Sucrose is a non- reducing sugar so these results would be expected, especially under the Benedict's which is a test for reducing sugars.

  2. Explain transcription and translation in protein synthesis.

    (Picture Source:- http://meyerbio1b.wikispaces.com/Transcription+and+Translation). The translation stage of protein synthesis. Protein synthesis is a continuous and vital operation within a cell. The synthesis of proteins for certain functions is fundamental to the continued health of a cell and an organism as a whole.

  1. Does ethanol causes greater inhibition of pig liver catalase than of yeast catalase

    chances of collisions occurring randomly between the catalase molecules and the inhibitor. Anomalous Results I had one anomaly in my data which I highlighted in my table 4 I removed this to process it as if I had used them they would have made my mean rates unreliable.

  2. Type - 1 Hypersensitivity Reaction

    was noted, however when the 0.4 of 10-4 M was added a greater contraction was measured, than the 0.2ml of 10-4 M of histamine. This response was a naturally elicited response via the histamine binding onto the h1 receptors on the surface of the tissue.

  1. The Effect Of Copper Sulphate On Pepsin Activity.

    As a result, the rate of reaction decreases as the concentration of copper sulphate increases which is demonstrated in graph 2. Due to this it is evident my hypothesis that as the concentration of copper sulphate increases the time taken for trypsin to catalyse the hydrolysis of casein will increase.

  2. Experiment 3 : Identification Of Food Constituents In Milk

    K2 A milky solution was formed. A milky solution was formed and red spots can be seen. Conclusion: Milk K1 is fat free whereas milk K2 contains a little amount of fat. Experiment 3(C) Objective: To compare the concentration of reducing sugar and protein in milk K1 and K2.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work