How does heating foods affect the amounts of Vitamin C they contain

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Laura Wetherill 10FJWa _                                18th May 2001

How does heating foods affect the amounts of Vitamin C they contain?


The aim of the experiment is to investigate how much Vitamin C / Ascorbic Acid is destroyed when Orange juice is heated at 80°C for different lengths of time.



Certain foods contain high concentrations of Vitamin C. When these foods are heated their ascorbic acid content decreases, this is a non-reversible reaction.

During the sterilisation process foods are heated and Vitamin C is destroyed. In order to maintain the initial concentration, Ascorbic Acid is added.                         

DCPIP (dichlorophenol-indophenol solution) is a dark blue indicator that turns colourless when a certain amount of Ascorbic Acid is detected.

The experiment is to determine the concentration of ascorbic acid present in five different solutions of orange juice, each of which has been pre-treated in a different manor as specified in table 1:

Table 1
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Fair Testing

  • The temperature of a substance affects the rate at which it reacts with another. This is because the molecules have more kinetic energy making them react faster. Therefore each test-tube of orange juice must be cooled to the same temperature (probably room temperature) before they are tested for their ascorbic acid content, otherwise the results will be inaccurate.
  • Using the same carton of orange juice should ensure that the Molar strength of each test solution is the same.
  • If a stopwatch is used instead of a standard watch to time the 1 – 5 minutes ...

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