Benedict's Test (Reducing Sugars)
- A wide range of biological molecules can be tested for using simple chemical tests
- This allows the biological molecules within a sample (such as a food substance) to be determined
- Reducing sugars include simple sugars like glucose that are just made from one unit (monomer), and some sugars made from two units joined together like maltose
- The presence of reducing sugars can be tested for with a Benedict's test
Test for a reducing sugar
- Add Benedict's reagent (which is blue) to the sample solution in a test tube
- Heat in a water bath that has been set at 75•C for 5 minutes
- Take the test tube out of the water bath and observe the colour
- A positive test will show a colour change from blue to orange/dark red
- An orange/dark red precipitate (solid particles suspended in the solution) will form
- A negative test will remain blue
- The amount of colour change is an indication of the amount of reducing sugar present
- From: blue → green → yellow → orange → red
The Benedict's test for glucose