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SCI125LabExercise2Browning.docxScience 125 The Science of Cooking
Lab Exercise 2 Browning in Apples and Potatoes
This experiment will allow you to observe the browning of apples and potatoes after treatment with solutions of varying pH.
1. Preparation of solutions for browning experiment.
A. Obtain and label 5 disposable plastic cups. i. Vinegar
ii. Lemon Juice iii. Baking soda
iv. Milk of Magnesia v. Water
B. Prepare the appropriate solution in each cup.
i. ¼ cup of vinegar in the first cup.
ii. ¼ cup of lemon juice in the second cup.
iii. Add ½ teaspoon of baking soda to the third cup, then add ¼ cup water. Swirl to dissolve the baking soda.
iv. Add ¼ cup of Milk of Magnesia and then add ¼ cup of water to the fourth cup. Swirl to mix well. You may need a spoon to get this solution to mix evenly.
v. Add ¼ cup of water to the fifth cup.
2. Preparation and treatment of apple slices.
A. Prepare a container to hold your apple slices. A plate or plastic storage container will work for this.
B. Place labels on the container. C for control or untreated and then labels i to v for the different solutions.
C. Prepare 6 apple wedge samples of approximately the same size. i. The exact size of the samples is not important.
ii. Cut the wedges so that they will easily fit into the solution cups
D. Treat the apple wedges as follows (You’re just going to dip the apple wedge into the
solution. Don’t leave it in the solution :
c. Control no treatment. Place on your container by the c i. Vinegar treatment
ii. Lemon juice treatment iii. Baking soda treatment
iv. Milk of Magnesia treatment v. Water treatment
E. Immediately after each treatment observe the apple slices and record your observations in the Data Table 4.1.1. It is usually helpful to take a photo of apple slices for comparison.
F. When making observations include: i. Color / extent of browning
white, lightly brown, very brown, pink/reddish ii. Moisture level
damp, dry, slimy iii. Texture
smooth, wrinkled
G. Make a minimum of two additional observations over the next 24 hour period.
i. The exact time of the observations is not important, but the approximate spacing is.
ii. Make the first observation 2 to 3 hours after preparation of the apples.
iii. Make the second observation 20 to 24 hours after preparation of the apples iv. Record the time of observation in the Data Table 2.1.1.
3. Preparation and treatment of potato slices.
A. Repeat steps A through G above this time using potato slices.
B. You can use the same solutions for the potato slices that you did for the apple slices. C. Record the data for the potato slices in Data Table 2.1.2.
Data Table 2.1.1. Apple Browning Observation
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0 Hours |
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______ Hours |
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Color |
Moist |
Texture |
Color |
Moist |
Texture |
Color |
Moist |
Texture |
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Data Table 4.1.2. Potato Browning Observations
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0 Hours |
_______Hours |
______ Hours |
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Color |
Moist |
Texture |
Color |
Moist |
Texture |
Color |
Moist |
Texture |
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Answer the following questions for the browning observations with both the apples and potatoes.
1. How does the color change in the samples dipped in solution compare to the color change in the control samples?
2. Which of the five experimental samples of the apple and potato had the greatest change in color? The least change in color?
3. Rank the color change from least to greatest for the five different solutions.
4. Did the acidic or basic solutions impact color change the greatest?
Science 125 The Science of Cooking
Lab Exercise 2 Browning in Apples and Potatoes
This experiment will allow you to observe the browning of apples and potatoes after treatment with
solutions of varying pH.
1.
Preparation of sol
u
tions for browning experiment.
A.
Obtain and la
b
el 5 disposable plastic c
u
ps.
i.
V
inegar
ii.
Lemon
Juice
iii.
Baking soda
iv.
M
i
lk of Magnesia
v.
Water
B.
Prepare the appropriate soluti
o
n in each cup.
i.
¼ cup of vinegar in the first cup.
ii.
¼ cup of lemon ju
i
ce in the second cup.
iii.
Add ½ teaspoon of baki
n
g soda to the third cup,
then add
¼ cup water.
Swirl to dissolve the baking so
d
a.
iv.
Add ¼
cup of Milk of Magnesia and then add
¼ cup of water to the fourth
cup.
Swirl to mix wel
l
.
You may need a spoon to get this solution to mix
evenly.
v.
Add ¼ cup
of water to the fifth cup.
2.
Preparation and treatment of apple s
l
ices.
A.
Prepare a container to hold you
r
apple s
l
ices.
A plate or plastic storage container
will work for this.
B.
Place labels on
the container.
C for control
o
r untreated and then labels i to v for
the different solutions.
C.
Prepare 6 apple wedge samples of approximately the same size.
i.
T
he exact size of the samples is not important.
ii.
Cut the wedges so that they will easily fit into t
h
e solution cups
D.
Treat the apple wedges as foll
o
ws
(You’re just going to dip the apple wedge into the
solution. Don’t leave it in the solution
:
c. Control no treatment.
Place on your conta
i
ner by the c
i.
V
inegar treatment
ii.
Lemon juice
treatment
iii.
Baking sod
a treatment
iv.
M
i
lk of Magnesia treatment
v.
Water treatment
Science 125 The Science of Cooking
Lab Exercise 2 Browning in Apples and Potatoes
This experiment will allow you to observe the browning of apples and potatoes after treatment with
solutions of varying pH.
1. Preparation of solutions for browning experiment.
A. Obtain and label 5 disposable plastic cups.
i. Vinegar
ii. Lemon Juice
iii. Baking soda
iv. Milk of Magnesia
v. Water
B. Prepare the appropriate solution in each cup.
i. ¼ cup of vinegar in the first cup.
ii. ¼ cup of lemon juice in the second cup.
iii. Add ½ teaspoon of baking soda to the third cup, then add ¼ cup water.
Swirl to dissolve the baking soda.
iv. Add ¼ cup of Milk of Magnesia and then add ¼ cup of water to the fourth
cup. Swirl to mix well. You may need a spoon to get this solution to mix
evenly.
v. Add ¼ cup of water to the fifth cup.
2. Preparation and treatment of apple slices.
A. Prepare a container to hold your apple slices. A plate or plastic storage container
will work for this.
B. Place labels on the container. C for control or untreated and then labels i to v for
the different solutions.
C. Prepare 6 apple wedge samples of approximately the same size.
i. The exact size of the samples is not important.
ii. Cut the wedges so that they will easily fit into the solution cups
D. Treat the apple wedges as follows (You’re just going to dip the apple wedge into the
solution. Don’t leave it in the solution :
c. Control no treatment. Place on your container by the c
i. Vinegar treatment
ii. Lemon juice treatment
iii. Baking soda treatment
iv. Milk of Magnesia treatment
v. Water treatment
