Apple Browning Experiment

How do you keep apples from turning brown? Do all apples turn brown at the same rate? Let’s try to answer these burning apple science questions with an apple oxidation experiment that is pretty quick and easy to set up at home or in the classroom. We paired this with more fun apple science experiments!

WHY DO APPLES TURN BROWN?

HOW TO KEEP APPLES FROM TURNING BROWN

Ever found a bad spot on an apple or opened a container in a lunch box filled with apple slices that were once pearly white and now look a bit on the used up side. The bad spot is definitely not tasty but the slightly browned apples aren’t all that bad!

Is it safe to eat brown apples? My son tasted the brown slices of his favorite apple, the honey crisp, and declared them still ok. Not all apples are similar in their rate of browning!

How do you keep apples from turning brown? Lemon juice is often suggested as a solution for keeping apples from turning brown. Does lemon juice really work and how does it stop or slow the browning process?

Let’s try a simple apple experiment and find out how to stop apples from browning!

WHY DO APPLES TURN BROWN?

There’s great science behind the process of why an apple turns brown or why rotten spots are brown.

The simple science is that when an apple is damaged, or even cut into slices, the enzymes in the apple react with the oxygen in the air, which is a process called oxidation. The apple produces melanin to protect the apple which is the browning you see.

We watched this short video on Why do Apples Turn Brown? which digs deeper into the exact science of polyphenol oxidase (PPO) enzymes. It’s a mouthful!

HOW DOES LEMON JUICE STOP APPLES FROM BROWNING?

Lemon juice helps keep the apple from turning brown because it is full of ascorbic acid (Vitamin C) and it has a low (acidic) pH level.

Ascorbic acid works because oxygen will react with it before it reacts with the polyphenol oxidase enzyme in the fruit. What else might prevent apples browning in a similar way?

VARIATIONS

We investigated whether lemon juice on apples stops them from turning brown in the experiment below.  Why not extend the learning and compare different ways to prevent cut apples from browning!

You could test…

• Ginger Ale
• Salt Water
• Ascorbic Acid Powder
• Plain Water

This apple experiment would make for a fun apples science project!

APPLE OXIDATION EXPERIMENT

This is a great experiment to set up using the scientific method for kids. Use our printable apple browning experiment worksheet below to record your observations.

The independent variable will be the type of apple, and the dependent variable will the amount of lemon juice you add to each apple. Can you think of any other dependent variables?

YOU WILL NEED:

• Apples! (We used 5 varieties of apples since we had just completed our apple 5 senses science activity beforehand.)
• Lemon Juice {or real lemon}
• Paper Plates, Knife, Small Cups {optional}
• Printable Journal Page

Click here to get your printable apple experiment worksheets!

APPLE EXPERIMENT SET UP

STEP 1: Label the paper plates with the name of each type of apple you are using.

STEP 2: Then cut two wedges of the same size out of each apple.

STEP 3: Place one wedge in a small dish and the other on the plate alongside the rest of the whole apple.

STEP 4: Squeeze a little lemon juice over each slice in the dishes and mix to coat evenly. Dump out excess juice. Do this for each apple.

STEP 5: Now wait and be patient. Record your observations.

If you want, set out a timer to get an accurate measurement of the time it takes for each apple to turn brown. This way you can record results in number of minutes for drawing conclusions later.

APPLE EXPERIMENT RESULTS

• Which apple turned first?
• Did they all turn equal shades of brown?
• Does the apple slice coated in lemon juice taste different than the plain apple slice?
• Does the brown apple slice really taste all that bad?
• Did the lemon juice really work?

BELOW WAS OUR QUICKEST TURNING AND DARKEST BROWN APPLE SLICE.

He went on to happily eat both slices of cut apple and found them tasty. Fall is a great time of year for exploring apples!

MORE FUN APPLE ACTIVITIES TO TRY

Learn about the parts of an apple.

Use our printable life cycle of an apple worksheets to explore how an apple grows.

Develop your observation skills with an apple 5 senses activity.

Enjoy apple crafts and art activities with simple supplies.

SIMPLE APPLE OXIDATION EXPERIMENT FOR KIDS

Check out more fun and easy fall STEM activities for kids.