How Do You Keep Guacamole From Turning Brown?
Difficulty of Project
$10-$15 (depending on whether avocados are in season)
Approximate Time Required to Complete the Project
A few days
- To understand how to stop the oxidation process from occurring in guacamole.
- To test different strategies for stopping this process.
Materials and Equipment / Ingredients
- Guacamole (homemade)
- An avocado pit
- Saran Wrap
- Lemon juice
After creating a homemade guacamole, you might discover that the guacamole will quickly turn brown. Why does this occur? When avocados are cut open, it allows the enzyme polyphenole oxidase to react with the oxygen in the air. This creates a melanoidin pigment, which turns the guacamole brown. How does one ensure that the guacamole does not turn brown?
- Does leaving the avocado pit in the guacamole stop it from turning brown?
- Does Saran Wrap stop guacamole from turning brown?
- Does lemon juice stop guacamole from turning brown?
- Which of these methods word the best?
Terms, Concepts and Questions to Start Background Research
- What causes guacamole to turn brown?
- How does oxygen interact with avocados?
- What are some proposed methods of preventing the guacamole from turning brown?
- Create four batches of homemade guacamole.
a. Leave one batch alone. This is your control.
b. In one batch, place an avocado pit on the top.
c. In one batch, squeeze some lemon juice into the mixture.
d. Spread Saran Wrap across the final batch.
- Leave the guacamole out on the counter, exposed to air.
- Observe how long each takes to brown. Once they are brown, feel free to throw them out.
McGee, Harold. The Curious Cook: More Kitchen Science and Lore. Hungry Minds Inc, New York: 1990.
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