• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

AIM: To determine the concentration of ascorbic acid in orange juices

Extracts from this document...

Introduction

´╗┐Title: Ascorbic Acid Test Aim: To determine the concentration of ascorbic acid in orange juices Introduction: Ascorbic acid is a reductone sugar acid with antioxidant properties, i.e., it is capable of inhibiting the oxidation of other molecules. It is one form of vitamin C and is therefore an essential nutrient for human species and certain other animal species. In animals, it plays a role in wound-healing and in preventing bleeding from capillaries and in humans, it is essential to a healthy diet and to the maintenance of connective tissue. The major food sources of ascorbic acid are green vegetables and citrus foods. Materials/ Apparatus: 0.1% DCPIP 4.0mg/ml of ascorbic acid 2.0 mg/ml of ascorbic acid 1.0mg/ml of ascorbic acid 0.5mg/ml of ascorbic acid Orange juice Sour orange juice Lemon juice Test-tubes Test-tube rack Procedure: 1. ...read more.

Middle

4. The procedure was repeated using fresh samples of DCPIP each time, with the four solutions of ascorbic acid, orange juice, sour orange and lime juice. 5. The results were provided in a table then a graph was plotted of the number of drops of ascorbic acid solution use to decolorized DCPIP against concentration of ascorbic acid solution. Results: Table 1. Ascorbic acid concentration and drops of DCPIP. Concentration of Ascorbic acid No. of drops used to decolorize DCPIP solution 4.0 mg/ml of ascorbic acid 8 2.0mg/ml of ascorbic acid 19 1.0mg/ml of ascorbic acid 25 0.5 mg/ml of ascorbic acid 60 Orange juice 25 Sour orange juice 37 Lime juice 50 Guava 11 Grapefruit 45 Table 2. ...read more.

Conclusion

Oxidized DCPIP is blue, reduced DCPIP is colorless. If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic acid. It required 8 drops of 4.0 mg/ml of ascorbic to decolorize the DCPIP. Then, to decolorize 2.0 mg/ml of ascorbic, it took 19 drops. Hence, an increase in the number of drops for the experiment suggests that the concentration of the ascorbic acids were high. Sources of Error: The ascorbic acid was not always dropped directly to the DCPIP solution. It fell to the side of the test tube which made the number of counts inaccurate. Processed juices may have been used which could alter the results because of the chemicals found in the juices. Conclusion: The concentration of ascorbic acid in orange juices are high. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

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

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