Digestion In The Mouth. Lab Report

Human salivary amylase: calcium ion
visible in pale khaki, chloride ion in green.

Hey there everybody. You are able to understand how your saliva changes your food. Simple experiment will provide you with useful information about the process of sugar digestion in the mouth. Use this scheme to do your work.

LAB WORK REPORT

Title: Digestion In The Mouth

Introduction: The digestion of starch begins in the mouth where it is mixed with saliva containing the enzyme salivary amylase.
Amylase changes starch into sugar.

In this exercise, the effects of amylase activity will be tested by checking for the disappearance of substrate (starch) at the end of the experiment. An easy experiment for a great science is to expose starch to saliva for different amount of time, spit the starch solution into containers, and then test the material for the presence of starch. A colour change indicates a positive test.

Test for Starch

Tincture of iodine (IKI) is used to treat wounds. It can be purchased where first aid supplies are sold. Iodine turns starch a dark blue-black colour.

Purpose: What affect does chewing time have on the amount of starch digested in the mouth? Is the activity of salivary amylase influenced by changes in pH? How?

Hypothesis: If the size and type of starch (bread) remain the same, as the chewing time increases the amount of starch digested increases. If pH changes then amylase activity is going to change too.

Equipment:

Procedure.

1. Place a starch into a cup.

2. Add saliva to expose starch to amylase enzyme for 60 seconds.

3. Add one tablespoon of water, and then add one drop of tincture of iodine.

4. Use a clean craft stick to thoroughly stir the contents of the cup. Place the craft stick in the trash.

5. Take a picture of the contents for a record of the colour of the results.

6. Repeat steps 1 through 5 five times, each time reduce the exposure time 10 seconds.

7. Repeat step 1 through 5, but this time change the pH by adding vinegar to the saliva (it is acidic, that is pH will decrease to 2.5-3).

Control

1. Place a starch in the remaining cup.

2. Add 1 tablespoon of water, and then add one drop of iodine.

3. Using the remaining clean craft stick, thoroughly stir the contents of the cup.

Result:

Conclusion:

1. Which cup(s) contained the most starch following experiment? Which cup(s) contained the most sugar? What conclusions can you draw from these results? 
2. Reviewing your data, predict what would happen to salivary amylase activity once saliva is swallowed? Explain.