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

Vitamin C content of fruit juices

Extracts from this document...


Title : The vitamin C content of fruit juice Objective : To investigate and compare the vitamin C content in various fruit juice Introduction: Vitamins are a group of complex organic compounds which play an essential role in animal metabolic processes but which the animal cannot synthesise. 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 constituents of the food of animals. Certain animals can synthesise certain vitamins. All animals which require vitamin D can synthesise it from ergosterol1 in the presence of U.V light. With the exception of vitamin D, the 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 or Ascorbic acid is a water-soluble vitamin. Vitamin C cannot be stored by the body as it is not a fat-soluble vitamin. Excess vitamin C leaves the body through the urine. Thus, we need a constant supply of vitamin C in our diet. The chemical compound of vitamin C is C6H8O6 while its IUPAC name is 2-oxo-L-threo-hexono-1,4-lactone-2,3-enediol. Image 1: 3D structure of vitamin C 2 Image 2: 2D structure of vitamin C 3 Vitamin C is essential for the growth and repair of tissues. ...read more.


10. The volume of 0.125g/100ml vitamin C solution required to decolourise the DCPIP solution is observed and recorded in a table (Table 1). 11. Steps 7 to 10 are repeated two times for each concentration of vitamin C solution and the average of the result is obtained. 12. Steps 7 to 11 are repeated by using vitamin C solution of concentration 0.250g/100ml, 0.500g/100ml, 0.750g/100ml and 1.000g/100ml. 13. The results are tabulated and a graph of vitamin C required to decolourise DCPIP solution against concentration of vitamin C solution is plotted (Graph 1). B) DETERMINATION OF VITAMIN C CONTENT OF FRUIT JUICE 1. Fresh orange is squeezed to prepare fresh orange juice. 2. This procedure is repeated with the fresh lime and fresh star fruit to prepare fresh lime and fresh star fruit juice. 3. 0.5ml of 1% DCPIP is measured by using a 3ml syringe and placed in a test tube. 4. 3ml of the prepared fresh orange juice is measured using a clean 3ml syringe. 5. The fresh orange juice is added drop by drop into the test tube containing the DCPIP solution until the DCPIP solution has been decolourised. 6. The volume of fresh orange juice required to decolourise the DCPIP solution is observed and recorded in a table. ( Table 2) 7. Steps 3 to 6 are repeated two times for each type of fruit juice and the average of the result is obtained. ...read more.


Each experiment carried out is also repeated twice or thrice to ensure the reliability of the result. The average value for each type of fruit juice is determined by dividing the sum of all the reading for that particular fruit juice by the number of readings taken. By repeating the same procedure, random errors such as parallax error can be minimized. The content of vitamin C of each type of fruit juice can be determined more accurately and may be closer to the theoretical value. A syringe with a needle or a smaller scale such as a 1ml syringe may also be used to improve the accuracy of the volume of vitamin C solution or fruit juice used. This is because an instrument with a smaller scale is more precise than an instrument with a bigger scale. Safety Precautions: The experiment must be carried out in a careful manner. A lab coat should be worn to prevent clothes from being stained dark blue by the DCPIP solution. Closed shoes should be worn in the lab to provide adequate protection in case of any mishaps. When cutting the tablet into smaller parts, the knife should be handled with care. Conclusion: The lower the volume fruit juice used to decolourise the DCPIP solution, the higher the concentration of vitamin C in the fruit juices. Orange juice contains the highest amount of vitamin C when compared with lime juice and star fruit juice. The hypothesis is accepted. ...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

3 star(s)

The writer has produced a clear and well-written account of an investigation into relative vitamin C concentrations in fresh and commercial fruit juices. While much of the report reflects good scientific practice, there were, however, a number of shortcomings that need to be addressed before this can be considered A-grade standard work. [1] The choice of juices to be tested needed to be justified. Furthermore, data from manufacturers together with researched values for vit. C concentrations in these juices should have been discussed prior to testing. [2] The hypothesis was not fully supported by research. [3] Controlled variables were not fully identified and dealt with. [4] The method used to construct a standard curve was very inaccurate - although this was commented on in the evaluation. [5] Anomalies were not identified. [6] The discussion of results was rather brief and did not really address the difficulties of comparing fresh and commercial juice. These are common weaknesses in investigation reports and students aiming for the higher grades need to address all these issues in their work. In this particular case, it would take a relatively small effort on the writer's part to rectify the shortcomings and turn this into a high quality piece of A'Level work.

Marked by teacher Ross Robertson 10/04/2013

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. Marked by a teacher

    Analysing the vitamin C content in different fruit juices

    5 star(s)

    Besides, vitamin C also is needed for the growth and repair of tissues in all parts of the body. It helps the body makes collagen which is an essential protein for making skin, cartilage, tendons, ligaments and vessels. Vitamin C is an antioxidant, like vitamin E, beta-carotene and many other plant-based nutrients.

  2. Marked by a teacher

    effect of concentration of copper sulphate on the action of amylase to break down ...

    4 star(s)

    Then I will only start pressing the measure button when the time gets close to the end point, so this will minimize the effect on the temperature of solution. Temperature of solutions- It is difficult to control the temperature of the solution throughout the whole experiment because I cannot put

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

    A beaker of boiling water was prepared. 5. Juice collected was heated in the water bath for 10 minutes. 6. The boiling tube was allowed to cool down. 7. 1 ml DCPIP solution was transferred to a test tube by a pipette.

  2. Free essay

    Food Group tables lipids proteins carbohydrates

    Protein may be found in a variety of food sources. Proteins from animal sources (meat, poultry, milk, fish) are considered to be of high biological value because they contain all of the essential amino acids. Proteins from plant sources (wheat, corn, rice, and beans)

  1. Explain transcription and translation in protein synthesis.

    uncoiled sections of a strand are re-formed allowing the strands to reunite into its double helical structure once again, this happen with the assistance of the enzyme DNA Polymerase. One newly transcribed mRNA molecule will possess a sequence of coded bases which possess an identical sequence to that of the

  2. An experiment to find of the isotonic point of root vegetables cells in contents ...

    30 30 0 1.5 1.3 -13.3 0.55 30 30 0 1.5 1.3 -13.3 0.6 30 29 -3.3 1.5 1.3 -13.3 Potato: Concentration Length before (mm) Length after (mm) % difference Mass before (g) Mass after (g) % difference 0.4 30 28 -6.67 1.6 1.1 -31.25 0.45 30 28 -6.67 1.6

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

    Knowing the amount of DCPIP needed to react with the orange juice at room temperature gave me an idea of the amount of vitamin C in the solution compared to the amount in heated solutions of orange juice. The more vitamin C in the solution, the more DCPIP needed to react with it.

  2. Molecules and cells - Edexcel GCE Biology Revision Notes

    that contains nutrients and growth hormones. This medium is sterile, so microorganisms can?t grown and compete with the plant cells. - Plant cells will grow and divide into a mass of unspecialized cells. If conditions are suitable (i.e. correct hormones) the unspecialized cells will then differentiate into specialized cells.

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