Chem Project Rough Draft - Amal, Akash and Aaqib 12C

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CERTIFICATE
ACKNOWLEDGEMENT
We would like to take the chance to thank everyone who

has supported us in completing this project.
A special thank you to our Principal, Mrs. Ambika Gulati,
and Headmistress, Mrs. Lini Shivaprasad, for their
unwavering support and inspiration.
My sincerest appreciation to Mrs. Shiji Hasan, our
Chemistry Teacher, whose assistance, direction, and
technical counsel allowed me to finish my project.
INDEX
Sr. No Topic Page

No.
1) Purpose 5
2) Introduction 6
3) Theory 7,8
4) Aim 9
5) Materials Required 9
6) Procedure 10
7) Observation 11
8) Result 11
9) Conclusion 12
10) Bibliography 13
1 PURPOSE
The purpose of this experiment is to explore the different

ways to reduce the browning of apples and the various
factors which affect the rate of browning.
We became interested in this topic when we were all
eating apples and they became brown. We realized that
this a phenomenon that we had all been casually ignoring
even though it happens quite frequently with all fruits.
We also wanted to find different ways on how to prevent
the browning of these apples and were fascinated by the
science behind it.
2 INTRODUCTION
Foods can turn brown due to an oxidation process called

"enzymatic browning," which primarily affects fruit and
vegetables. Enzymes are among the many distinct
chemicals that make up food. Special proteins called
enzymes can hasten chemical reactions and serve as
biological catalysts. They can make fruit ripen and become
overripe, turning the fruit dark.
Enzymes are typically retained in the tissues of fresh

produce. However, the enzymes come into contact with
oxygen in the air when the fruit is cut or squished, or when
the fruit or vegetable starts to deteriorate with age. The
fruit becomes brown as a result of this.
Enzymatic browning can be a serious issue, reducing the

shelf life of numerous fruits and vegetables that have
undergone minimal heat processing. Enzymatic browning
isn't always a problem, though. The browning reaction
helps raisins, prunes, coffee, tea, and cocoa maintain their
appealing color and flavor.
3 THEORY
When the apple is cut or peeled, an enzyme known as

“polyphenol oxidase” (often called phenolase) is released.
This enzyme when exposed to oxygen catalyses the
reaction which leads to the formation of a brown pigment
known as melanin. This reaction is called enzymatic
browning and it occurs at warms temperatures when pH is
between 5.0 and 7.0.
Enzymatic browning can be reduced by treated the slices
with different substances, for example, acids. The degree
to which the reaction is reduced depends on various
factors like concentration and type of substance.
Presence of Iron and copper can increase the rate of this

reaction. This phenomenon can be observed when an
apple is cut with a rusty iron knife.
When apples and other fruits gets bruised, the
arrangement of chemicals within the cell is disturbed and
these chemicals are exposed to oxygen. This could lead to
enzymatic browning.
4 AIM
To analyze the factors behind the browning of apples and

to find the best methods to prevent the browning
5 MATERIALS REQUIRED
• Apples
• pH paper
• Glasses/cups
• Tongs
• Knife
• Laboratory gloves
• Timer
• Pens
• Lemon juice
• Orange juice
• Soda
• Mineral water
• Baking soda
6 PROCEDURE
• 1 Test the pH of all the substances by using the pH

strips.
• Cut apples into slices and line them up on a table
• Place an apple slice on a paper towel. Label the
paper towel as “No Solution”.
• Dip one apple slice into each of the substances with
the help of tongs, for 30 seconds. Place the slices on
towels and label the towels with the name of the
solution.
• Do the same with an apple slice but soak the slice
with water and label the towel. “Water”.
• Then record the time taken for each apple slice to
brown (dark brown colour) with the help of a timer.
• Note the time and temperature in a table.
7 OBSERVATION
Time Taken For Apple to Brown
Water 1…
Black Cofee 0
Milk 21
Tomato Juice 8
Orange Juice 24
Lemon juice 27
0 5 10 15 20 25 30
Time Taken For Apple to Brown

8 RESULT
From the above observations, we can infer that out of all

the substances, lemon was the best preservative to
prevent browning of apples whereas baking soda was the
worst.
In the increasing order, the effective of the substances as
preservatives is:
Baking soda<orange juice<no solution<water<mineral
water<soda<lemon juice
We also observed, on repeating the experiment that apple
slices are best preserved at warm temperatures around 30
C and worst preserved at cold temperatures around 0 C.
9 CONCLUSION
From this project we have learnt about how and why

apples turn brown in colour, we learnt about enzymatic
browning. We have learned the real-life importance of
understanding enzymatic browning. We hope, that if you
are reading this project, that you now have a better
understanding of this topic. We hope this project was
interesting to go through and lastly, thank you for taking
the time to read through this project which we have
worked on.
10 BIBLIOGRAPHY
• https://www.ifst.org/lovefoodlovescience/resources/f
ruit-and-vegetables-enzymic-
browning#:~:text=Enzymic%20browning%20is%20an
%20oxidation,oxidation%20in%20order%20to%20oc
cur.
• https://letstalkscience.ca/educational-
resources/stem-in-context/why-do-apples-turn-
brown-after-you-cut-them
• https://news.wisc.edu/curiosities-why-do-apple-
slices-turn-brown/
• https://www.sciencefocus.com/nature/why-do-
apples-turn-brown-so-fast/
• https://www.sciencedirect.com/topics/food-
science/enzymatic-browning
• https://journals.ashs.org/hortsci/view/journals/hortsc
i/45/8/article-p1150.xml

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[Grab your reader’s attention with

We would like to take the chance to thank everyone who

Sr. No Topic Page

The purpose of this experiment is to explore the different

Foods can turn brown due to an oxidation process called

Enzymes are typically retained in the tissues of fresh

Enzymatic browning can be a serious issue, reducing the

When the apple is cut or peeled, an enzyme known as

Presence of Iron and copper can increase the rate of this

To analyze the factors behind the browning of apples and

• 1 Test the pH of all the substances by using the pH

Time Taken For Apple to Brown

Time Taken For Apple to Brown

From the above observations, we can infer that out of all

From this project we have learnt about how and why

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