For your prelab
do all of the sections and instruction printed in red!
What’s In a Big Mac?
INTRODUCTION
(take Notes)
You
may think you can tell what a food is by looking at it. Maybe so, but it isn't that easy to tell what
nutrients it contains. We have chemical
tests to show if certain food contains fat, starch, glucose (the kind of sugar
the body uses) or protein.
Today
you will practice using these tests. In
most cases, the chemical you test with will show a color change when it is mixed with a particular nutrient.
You are going to
determine what nutrients are in the two
all beef patties, special sauce, cheese and bun of a Big Mac.
4
test tubes beaker
Big
Mac Solutions Reagents
Beef
patties Benedict's
solution
Special
Sauce Biuret
solution
Cheese iodine
Bun paper
bag
PART ONE
Observe the demonstration reactions of the known nutrients with the reagents. Use DATA TABLE #1 to record your observations. And then answer the following questions.
Brown bag test
A. Which nutrient left a spot that didn't seem
to dry?
B. Which nutrient can be identified with a brown paper bag?
Biuret Test
A. Which test tube shows a color change other
than blue?
B.
What color is it?
C.
Do the other test tubes show any change other than blue?
D. Which nutrient can be identified by
adding Biuret solution?
Iodine Test
A. Which test tube shows a color change other
than brown?
B.
What color is it?
C.
Do the other test tubes show any change other than brown?
D.
Which nutrient can be identified by adding iodine?
Benedict’s Test
A. Which test tube shows a color change other
than blue?
B.
What color is it?
C.
Do the other test tubes show any change other than blue?
D.
Which nutrient can be identified by adding Benedict's solution and
heating?
PART TWO (Flow chart all portions of the procedure
form this point to the end of the procedure)
Fill a large
beaker half full of water and
heat it on the hot plate at a
setting of 5.
Get four
pieces of paper bag. Write the name of one of the Big Mac parts on
a piece of paper. Place one drop of
solution on the bag with its name. Set the pieces to the side while you do the
other tests. After completing Parts
three through five, hold the pieces of paper up toward the light and look at
the spots to see which are translucent and which are not translucent.
RECORD YOUR OBSERVATIONS IN A DATA
TABLE.
Follow these steps for the next three tests:
Get four test tubes. Use a PENCIL to number the test tubes
1,2,3,4.
In test tube 1, put 10 drops of beef
patty solution.
In test tube 2, put 10 drops of
special sauce solution.
In test tube 3, put 10 drops of
cheese solution.
In test tube 4, put 10 drops of bun.
Add four
drops of Biuret solution
to each test tube.
RECORD YOUR RESULTS IN THE DATA
TABLE.
PART FOUR
Wash out the test tubes very
carefully. Set them up again with the
four nutrients as you did for Part Two.
Then add four drops of
iodine to each test tube.
RECORD YOUR RESULTS IN THE DATA
TABLE.
PART FIVE
Wash out the test tubes very
carefully. Set them up again with the
four nutrients as you did for Part Two.
Then add ten drops of Benedict's solution to each test
tube. Place the test tubes in hot water. Watch them until you see a color change.
RECORD YOUR RESULTS IN THE DATA
TABLE. .
DATA
Make the following Data table:
TABLE # 1 – Reactions of Nutrient with
Reagents.
|
|
glucose |
starch |
protein |
fat |
|
Brown paper bag |
|
|
|
|
|
Biuret solution |
|
|
|
|
|
Iodine |
|
|
|
|
|
Benedict's solution |
|
|
|
|
Make
a table for the Big Mac results.
ANALYSIS
Prepare an organized table indicating
which tests showed positive results for the different nutrients.
CONCLUSION
Write a paragraph explaining which
nutrients were found in each of the parts of the Big Mac.
EVALUATION
How accurate was your work? What types of problems did you have?