======Action of Salivary Amylase on Starch======


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**Alternative titles:** Saliva Breaking Down Starch
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====Summary====                   
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====Procedure====  
  - Cook some white rice until soft and allow it to cool slightly.  
  - Place a small portion of rice into two test tubes, or just use starch power.  
  - Add a few milliliters of water to each tube and mash the rice into a suspension.  
  - To one test tube, add a small amount of fresh saliva and mix. Leave the other tube as a control without saliva.  
  - Incubate both tubes at room temperature for several minutes.  
  - Test samples from both tubes with iodine solution to check for the presence of starch (a blue-black color indicates starch).  
  - Test samples with Benedict’s solution and heat in a water bath to check for reducing sugars (a green to red color indicates the presence of glucose or maltose).  
  - Compare results from the saliva-treated sample with the control sample.



====Links==== 
Action of saliva on starch | Digestion | Biology - KClassScienceChannel: 
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The starch & amylase experiment - Paul Scott: 
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📄 Salivary amylase and starch - Science Learning Hub: [[https://www.sciencelearn.org.nz/resources/1846-salivary-amylase-and-starch]]\\

====Variations====
  * Repeat the experiment using cooked potato or bread instead of rice.  
  * Compare results when saliva is boiled first to demonstrate enzyme denaturation.  
  * Test the effect of different incubation temperatures (e.g., chilled, room temperature, and warm water bath).



====Safety Precautions====
  * Safety glasses should be worn when handling iodine and Benedict’s solution.  
  * Use caution with hot water baths to prevent burns.  
  * Use only your own saliva and do not share samples to avoid cross-contamination.  The use of saliva may not be allowed at your site.
  * Dispose of biological material safely after the experiment.




====Questions to Consider====
  * What happens to the starch in the saliva-treated sample compared with the control? (The starch breaks down into sugars in the saliva-treated sample, while starch remains in the control.)  
  * Why does iodine change color in the presence of starch? (It forms a complex with the helical structure of starch molecules.)  
  * What does the color change in Benedict’s solution indicate? (The presence of reducing sugars like maltose or glucose.)  
  * Why is temperature important for enzyme activity? (Enzymes work best at their optimal temperature; high heat can denature them, while low temperatures slow their activity.)  
  * Why is it important to control variables in this experiment? (To ensure changes in results are due to enzyme activity and not other factors.)