Sweet Cracker

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Catalysts, Enzymes and Digestion, Food Science and Nutrition

Alternative titles: The Science of Spit, Amylase in Action

Summary

The enzyme amylase in saliva breaks down starch into sugar. A cracker initially tastes bland, but the longer it is chewed, the sweeter it becomes as starch is converted to glucose.

Procedure

Take a plain saltine cracker (or a piece of bread) and rub off any salt.
Place the cracker in your mouth and begin chewing, paying attention to the flavor.
Do not swallow; continue chewing for one to two minutes.
Notice the change in taste as the cracker becomes slightly sweet.

Links

Amazing Enzymes - Operation Ouch:

Description or Video title2 - Author2: demonstrations

📄 Part A: Sweet cracker - National Science Week: https://www.scienceweek.net.au/wp-content/uploads/2023/06/Enzymes-in-Action.pdf

Variations

Compare how long it takes different people to notice the sweet taste.

Safety Precautions

Use your own saliva only; do not share food with others.
Dispose of any food used in the saliva test—do not eat it afterwards.
Be cautious with food allergies (bread and crackers may contain gluten).

Questions to Consider

Why does a cracker taste sweeter after chewing for a while? (Because amylase in saliva breaks starch into glucose, which tastes sweet.)
Why can’t your body directly use starch molecules? (They are too large to pass through cell membranes.)
How does glucose benefit the body once it is produced from starch? (It is small enough to enter cells and provide energy.)