What experiment do you perform to understand action of saliva on flour? Explain it’s procedure and apparatus that you followed.
A. Experiment to understand action of saliva on flour.
Aim : To demonstrate the action of saliva on flour.
Apparatus : Test tubes (2), flour, watch glass, dilute tincture iodine, saliva (1 teaspoonful)
1) Take a test tube half-filled with water and add a pinch of flour to it.
2) Shake the test tube well till the flour gets mixed.
3) Take a few drops of this mixture in a watch glass and test for the presence of starch by putting a drop of dilute tincture iodine in it.
4) A blue-black colour confirms the presence of starch.
5) Now again dissolve a pinch of flour into half-filled water in a test tube.
6) Now divide the mixture into two equal halves by transferring it to another test tube.
7) Note that both the test tubes have the same amount of solution.
8) Add a teaspoon of saliva to one of the test tube and mark it.
9) Do not add anything in the other test tube.
10) After sometime (45 minutes) add a drop of dilute tincture iodine solution to test tubes containing the solution.
1) The solution of the test tube to which saliva is added shows colour change as starch is converted to sugar.
2) There is no colour change in the other test tube to which saliva is not added. Inference
The enzyme amylase in the saliva breaks down the starch molecules into smaller subunits usually into sugars.