Testing For Non-Reducing Sugars

Method: For this experiment I am going to:

• Measure 5cm of Sucrose Solution into a boiling tube and add 1cm of dilute Hydrochloric Acid (HCl)
• Stand the Tubes in a Boiling Water Bath by using a rack and leave for 5 Minutes. Remove the Rack with all the Test Tubes and leave to cool for a short period of time.
• Carefully add Sodium Hydrogen carbonate to the solution in the tubes, this should cause a reaction to occur where the solution fizzes. Add small amounts of Sodium Hydrogen carbonate until the fizzing eventually stops.
• Now add 3cm of Benedict’s Solution and return the rack with the tubes into the boiling water bath. Leave for 8 minutes, and then remove the rack with the tubes inside. A reaction should have taken place and a Colour Change should be apparent.

Results: After completing the experiment, I took down the colour changes in each of the tubes that contained a specific solution of Glucose and then compared it with a Sample to test the Sucrose Solution.

 From the results we can see that Orange Juice and Apple Juice have the highest amount of Sugar present inside of them, however Apple Juice has the highest, whilst Milk doesn’t react this means that it

Explain: Hydrochloric acid neutralised with Sodium Hydrogen Carbonate. Introduction Benedict's test uses copper (II) sulphate. This reagent is used as a general test for detecting reducing sugars. If the saccharide is a reducing sugar, it will reduce the copper (II) ions to copper (I) oxide, and form a red precipitate. However, some saccharides need to be split and neutralised in order to detect their reducing sugars. Risks Hydrochloric acid is very poisonous and corrosive if spilt wash affected area immediately.

Sucrose is the only common example of a non-reducing sugar. Heating Sucrose with hydrochloric Acid Hydrolyses the Sucrose into its two constituent monosaccharides, Glucose and Fructose, which are both reducing sugars and so react with the Benedict’s Solution