3. Test For Reducing Sugars

Introduction

This method determines if the fruit/vegetable juices contain reducing sugars (meaning glucose) and if they contain a small amount or a large amount. For this test slight heating is required and benedict’s solution is used as the indicator. One can only get a qualitative result for this experiment.

 

Apparatus and Materials:

• Juice extractor

• Juice samples

• Test tubes

• Test tube rack

• Pipettes

• Bunsen burner

• Benedict’s solution  

 

Method:                                                                                                                                                                                           

1.    A sample of the juices was each placed into 4 different test tubes.

2.    A few drops of benedict’s solution were added to each test tube and stirred well so it can be incorporated in the juice.

3.    The test tubes were placed in a water bath and heated gently.

4.    Observations were taken. If the solution turned brick-red then there was a large amount of sugars, if it turned brownish-orange        then there was a small amount and if it remained blue (the colour of the benedict’s solution) then there weren’t any sugars              present.

 

(Note: some of the solutions may have not turned to brick red because they contained Non-reducing sugars, e.g: sucrose)