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    Apple Browning Experiment

    Uploaded by

    Raul Herrera
    This document provides instructions for an experiment to explore why apples turn brown when cut or sliced. Students will slice an apple into quarters and coat each slice with a different liquid - lemon juice, vinegar, or pineapple juice - to see which is most effective at preventing browning. The document explains that apples brown due to a chemical reaction between oxygen in the air and an enzyme in apples. Certain liquids can slow this reaction by creating an oxygen-free environment.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Apple Browning Experiment

    Uploaded by

    Raul Herrera
    17 views2 pages
    This document provides instructions for an experiment to explore why apples turn brown when cut or sliced. Students will slice an apple into quarters and coat each slice with a different liquid - lemon juice, vinegar, or pineapple juice - to see which is most effective at preventing browning. The document explains that apples brown due to a chemical reaction between oxygen in the air and an enzyme in apples. Certain liquids can slow this reaction by creating an oxygen-free environment.

    Original Description:

    Testing browning of apples

    Original Title

    Apple-Browning-Experiment (1)

    Copyright

    © © All Rights Reserved

    Available Formats

    PDF, TXT or read online from Scribd

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    This document provides instructions for an experiment to explore why apples turn brown when cut or sliced. Students will slice an apple into quarters and coat each slice with a different liquid - lemon juice, vinegar, or pineapple juice - to see which is most effective at preventing browning. The document explains that apples brown due to a chemical reaction between oxygen in the air and an enzyme in apples. Certain liquids can slow this reaction by creating an oxygen-free environment.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    17 views2 pages

    Apple Browning Experiment

    Uploaded by

    Raul Herrera
    This document provides instructions for an experiment to explore why apples turn brown when cut or sliced. Students will slice an apple into quarters and coat each slice with a different liquid - lemon juice, vinegar, or pineapple juice - to see which is most effective at preventing browning. The document explains that apples brown due to a chemical reaction between oxygen in the air and an enzyme in apples. Certain liquids can slow this reaction by creating an oxygen-free environment.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 2

    Description: Explore the chemical reaction behind apple browning.

    Conduct your own experiment!

    Grades: 2+
    Ability Level: Easy
    Time: 6 hours

    Tools:
    o 1 apple, sliced into quarters
    o 3 small bowls or cups
    o Lemon juice
    o Vinegar
    o Pineapple juice
    o 3 cotton balls
    o Clock or timer

    Experiment Instructions:
    Before you start the experiment, discuss with your family: What happens when you cut or bite
    into an apple and leave it out? Why do you think it turns brown? How can we prevent the apple from
    turning brown?

    1. Set one piece of the apple off to the side. This slice will be left alone and will serve as the
    “control” for the experiment.
    2. Measure out each type of liquid into a separate bowl or cup.
    3. Dip a cotton ball into the lemon juice and dab the juice all over the surface of one of the apple
    slices. If you don’t have cotton balls, you can also dip the apple slice into the liquid for about 30
    seconds.
    4. Repeat this process with a fresh cotton ball for vinegar and one for pineapple juice. Apply one
    to each an individual slice.
    5. Place the four apple slices on a plate and let sit out for a day. Make sure you remember which
    apples were coated with specific liquids – it might help to label them (see image above).

    Discuss with your family: Which liquid do you think will be best for keeping the apple slice from
    browning? Why do you think that?

    6. Throughout the day, check on the apple slices and record your observations on the other side
    of this sheet. Take pictures if you want. Compare the slices to each other: Which slice is the
    brownest? Which slice is the least brown? Do you notice a change in the smell or texture of the
    apples?
    7. After about 6 hours, observe your final results! Which method would you use to preserve sliced
    fruit before eating it? Why?
    Record Your Observations!
    Scientists make observations to help answer questions about the world around them. Use this
    chart to help keep track of your own observations during the apple browning experiment!

    Time of Notes (e.g., what does each slice look,


    Apple slice with:
    Observation smell,feel)

    No Liquid (Control)

    Lemon Juice

    Vinegar

    Pineapple Juice

    The Chemistry Behind Apple Browning


    Why do apples turn brown when you leave them out?
    When you slice or bite into an apple, you are exposing it to oxygen in the air. Oxygen activates
    an enzyme in the apple called polyphenol oxidase. Enzymes speed up chemical reactions – in
    this case, speeding up the browning of the apple by releasing melanin. This chemical reaction,
    called “enzymatic browning,” can be simplified to:

    Polyphenol Oxidase (enzyme in the apple) + Oxygen (in the air) → Melanin (brown color)

    Different apples will brown at different rates because their chemical contents vary. This reaction
    is not unique to apples! Pears, bananas, and eggplants have this reaction and the result is a
    similarly unappealing brown mush. You can try this experiment with different types of apples or
    even different types of fruit!

    How can we prevent apples from turning brown?


    To slow the chemical reaction, you can isolate the fruit in an anaerobic – or oxygen-free –
    environment. This is possible by placing lemon juice or pineapple juice on the apple. These
    liquids carry antioxidants which eliminate oxygen. Oxygen in the air reacts to ascorbic acid in the
    lemon and pineapple juice before it reacts with the enzyme in the apple.

    Share your experience! Scan the code on the left with


    your smart phone’s camera to take a brief survey that will
    help us improve this experiment for families like yours!
    https://kent.qualtrics.com/jfe/form/SV_401gFT0z9eogZox

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