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Food Science
Mentor Science Olympiad Invitational 07/08
Names: _____________ANSWER KEY___________
School: _______From Mason High School ([email protected])
Team Number: ___________________
Cleaned up well: __________
Followed all safety guidelines: _________
FINAL SCORE: ___________
Rank: ___________
PLEASE READ:
 Be Safe!! Keep your Goggles On or points will be deducted.
 Clean up! Be sure the lab station returns to its original conditions or points will
be deducted.
 You may separated pages and work on experiments in any order. Be sure the
packet gets put back together in the correct order.
 GOOD LUCK!! 
WEAR YOUR GOGGLES AND APRON THROUGH OUT THE DURATION OF THIS EVENT!!!
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Exp #1: The Complete Marshmallow Analysis (45 pts total)
PART 1: Calories in a Marshmallow
DATA TABLE:
1. Record measurements from experiment here. Be sure to record digits to greatest accuracy possible.
(4 points)
Mass of Marshmallows:
1.344 g
Volume of water used:
100.0 mL
Initial Temperature of water:
22.0oC
Final Temperature of water:
41.0oC
CALCULATIONS:
1. In this calorimetry experiment, we are making the assumption that the heat lost by the marshmallows was gained by the water.
What is the formula you should use to calculate the heat released by the marshmallows, q marshmallows. (2 pts)
qmarshm. = - qH2O
qmarshm. = - (mCT) or -(msT)
2. Use the formula above, and calculate the Calories in your marshmallow sample. Assume that the heat capacity of the
calorimeter is negligible. SHOW AND LABEL YOUR WORK VERY CLEARLY. (2 pts)
** Density of water = 1.00 g/mL
** Specific heat of water = 1.00 cal/g.oC
** 1,000 calories (cal) = 1 kilocalorie (kcal) = 1 Calorie (Cal)
qmarchm. = - ( 100.0g x 1.00 cal/g.oC x (41.0oC-22.0oC ) = -1900. cal
-1900. cal x
1Cal
=
1000 cal
- 1.90 Cal
3. Calculate the Calories released per GRAM of marshmallow.
(2 pts)
Mass of marshmallow burned =
qmarshm./g =
- 1.90 Cal
= -1.41 Cal/g
1.344 g
4. Using the Nutrition Facts label from the peanut container, calculate the actual heat release per gram of marshmallow. (2 pts)
Nutrition Facts
q/g =
Serving Size 2/3 cup (30 g)
Servings Per Container 15
5. Calculate your percent error for this experiment. (2 pts)
Amount Per Serving
Calories
Total Fat 10g
Sodium 25mg
Total
Carbohydrate 25g
Sugars 18g
100Cal
 3.33 Cal/g released
30 g
100
% DV
0%
1%
8%
% Error =
3.33  1.41
x 100 = 57.7%
3.33
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6. List THREE possible errors that took place in the experiment that might contribute to your percent error. (3 pts)
1) Lost lots of heat to the environment (not absorbed by can)
2) The water temp was not uniform, not stirred well (hotter at the bottom)
3) The marshmallow did not burn all of the way.
etc
7. In addition to calorimetry, food chemists can also conduct other chemical analysis to determine the composition of a food item.
a. Briefly, what is the purpose of a Kjeldahl analysis?
(2 pts)
Method of estimating protein content in foods by quantifying the amount of nitrogen from the
amino acids. The one problem with this method is that it includes nitrogen from non-protein sources
too!
b. Briefly, what is the purpose of a hexane extraction. (2 pts)
Method of extracting the nonpolar components of food, fats and oils. Then, total fat content can be
quantified in a food item.
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PART 2: Macromolecule Composition of a Marshmallow
Conduct the basic macromolecule tests on a marshmallow to determine its composition.
GENERAL PROCEDURE:
1. Place a marshmallow in about 20 mL of water in a small beaker. Swirl the marshmallow around to get
it to dissolve. It won’t ALL dissolve.
2. Use this solution to conduct the following tests:
TEST 1: Benedict’s Test
1. Add one full squirt of marshmallow solution into a test tube.
2. Add 4 drops of Benedict’s reagent. Tap test tube to mix.
3. Heat the test tube for 3 minutes in the provided boiling water bath. PLEASE BE CAREFUL!!!
4. Remove the tube, handling them from the rim and record the results on the data table.
TEST 2: Iodine Test
1. ½ fill a well on the well plate with marshmallow solution.
2. Add 2 drops of iodine solution to well and mix with toothpick.
3. Record results on data table.
TEST 3: Biuret Test
1. ½ fill a well on the well plate with marshmallow solution.
2. Add 2 drops of Biuret test reagent to well and mix with toothpick.
3. Record results on data table.
PART 2: Macromolecule Composition of a Marshmallow
DATA: (6 pts)
Observations:
What do your observations
tell you about the
composition of a
marshmallow:
Results of Marshmallow solution with
Benedict’s solution:
Yellow, orange
precipitate
Indicates the presence
of reducing sugars
(glucose, fructose…)
Results of Marshmallow solution with
Iodine solution:
Solution turned deep
blue
Indicates the presence
of starch
Results of Marshmallow solution with
Biuret’s solution:
No rxn
Proteins not present at
a measurable level
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ADDITIONAL QUESTIONS: (12 pts) Please answer the questions on the blank on the left. Each blank is
worth 1 pt.
+
________Cu ___ ______Cu2O____
1. In the Benedict’s test, an aldehyde group gets oxidized to a carboxylic acid.
Meanwhile, Cu2+ gets reduced to ____ in the form of _____, which is a reddish
precipitate.
_______Glucose_________
2. The main ingredient in marshmallows, not surprisingly, is corn syrup. Corn syrup
is primarily what sugar?
_High
3. Related to corn syrup, the most common sweetener used in soft drinks has the
acronym, HFCS 55. What does HFCS stand for?? What does the “55” stand for?
Fructose Corn Syrup_
_55 means 55% Fructose and 45% Glucose (classic blend that’s very equivalent to sucrose)___
__Gelatin
(or collagen)___
_25%_75% __Amylose__
4. A strict vegetarian would probably exclude marshmallows from their diet. What
is the specific ingredient in a marshmallow that is extracted from the bones,
connective tissues, organs, and some intestines of animals. This particular
ingredient adds to a marshmallows spongy texture.
5. Corn starch is made up of approximately ____ % amylose and _____%
amylopectin. The I2 in the Lugol’s starch test interacts with the ____ portion.
6. Circle which of the following would NOT contain corn starch? You can circle more than one.
Chicken gravy
____peptide_____
Pizza
Mayonnaise
Honey
Powdered sugar
7. In the Biuret’s test, Cu2+ form a coordinate complex with nitrogen atoms involved
in the ____ bonds of the proteins creating a lovely shade of violet.
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PART 3: % Air in a Marshmallow
Obviously, a good percentage of a marshmallow is nothing more than air. In this part, you will
experimentally determine the % air in a marshmallow.
1. Using the formula, Vcylinder =  r2h, and a ruler to calculate the volume of a marshmallow.
2. Put the marshmallow in the syringe and squeeze the syringe to remove all of the air. Measure the new
volume of the de-aired marshmallow. The units on the syringe are also cm3.
3. Calculate the % Air by volume in a Marshmallow.
PART 3: % Air in a Marshmallow
1. Calculate the radius and height of a puffed marshmallow. (1 pt): ___0.50
cm___
____1.20 cm____
2. Calculate the volume of a puffed marshmallow (2 pts):
V = (3.14)(0.50cm)2(1.20cm)=0.94cm3
3. Measure the volume of a de-aired marshmallow (1 pt): _____0.4
cm3___
4. Calculate the % Air in a marshmallow (2 pts):
% Air =
0 .4
x 100 = 43%
0.94
Exp #2: % Sugar in Beverages
Almost all soft drinks that are not milk-based (Coke, Sprite, Kool-Aid, etc) are essentially sugar solutions with small
amounts of additives for flavoring and color. You will determine the density of different sugar solutions and make a
graph of density vs % sugar. This is called a calibration curve. You will use the calibration curve and the density of
each beverage to determine the % sugar in each beverage you test.
PROCEDURE:
Measure and record the mass and volume of a 0%, 5%, 10%, 15% and 20% sucrose solution. Do the same for the
Coke and Diet Coke samples.
-
Place a 250 mL beaker on the electronic balance. You will add all of your solutions to this beaker to determine
their masses. Push tare in between each measurement.
Use a 10 mL pipet to precisely measure the volume of 10.00 mL of solution. Be sure to extract ALL of the
liquid from the pipet into the beaker. Record the mass.
Dry the outside of the pipet in between each new solution.
Dump the solutions down the drain when you are finished.
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Exp #2: % Sugar in Beverages (27 pts total)
DATA: (10 pts)
Substance:
Mass:
Volume:
Density: (D=m/V)
0% Solution
9.807 g
10.00 mL
0.9807 g/mL
5% Solution
10.04 g
10.00 mL
1.004 g/mL
10% Solution
10.21 g
10.00 mL
1.021 g/mL
15% Solution
10.32 g
10.00mL
1.032 g/mL
20% Solution
10.53 g
10.00 mL
1.053 g/mL
Coke
10.27 g
10.00 mL
1.027 g/mL
Diet Coke
9.839 g
10.00 mL
0.9839 g/mL
CALCULATIONS/ANALYSIS:
1. On the graph below, graph % sugar on the x-axis and density on the y-axis. Draw a best fit line. (4 pts)
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2. Use your graph, to determine the % sugar in the coke and diet coke sample. NOTE: Diet coke and coke zero, of course, don’t
have any sugar in it. It’s percentage off of the graph, therefore, is equivalent to % sweetener. (4 pts)
% Sugar for Coke is ___12.7%
(very flexible!)___
% Sweetener for Diet Coke is ____0.2 %
(very flexible)____
3. Let’s use freezing point depression data and the information above to determine the identity of the artificial sweetener in Diet
Coke.
a. An experiment was conducted where Diet Coke was frozen (Diet Coke-sicles! YUM!!!). Using the data and
formula below, calculate the molality ( m 
moles of solute
) of the Diet Coke. (2 pts)
kg of solvent
Freezing Point Depression Formula: Tf = Kfm
Molal Freezing Point Depression constant, Kf: 1.86oC/m
T (initial): 0.00000oC
T (final): -0.00339oC
** Yeah, I know. The temperature data is a little unrealistic! 
0.00339oC = (1.86oC/m)(m)
m = 0.00182 m (mol/kg)
b. Using the molality above and the actual % by mass of sweetener in diet coke (0.054%), calculate the Molar Mass of the
artificial sweetener. Remember, molar mass is mass per mole of a substance. (3 pts)
0.00182 mol
1 kg solvent
0.054g
0.054g
1000 g
% H2O =
=
x
= 0.540 g/Kg H2O
100 g solution
99.946 g H2O 1 Kg H2O
m=
Molar Mass =
0.540 g
mass
=
= 296 g/mol
mol
0.00182 mol
c. Based on your answer to B, what artificial sweetener is used in Diet Coke??? Circle your answer. (2 pts)
Saccharin, 183.89 g/mol
Acesulfame potassium (Ace-K), molar mass = 201.24 g/mol
Aspartame, molar mass = 294.30 g/mol
Sucralose, molar mass = 397.64 g/mol
4. In a nutshell, why are the diet soda’s so much less dense than regular coke??? (2 pts)
Aspartame is many more times (180-200 x) sweeter than sugar per gram. You
don’t need nearly as much aspartame to accomplish the same level of sweetness.
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Station 3: Match that Label ( 16 pts Total)
TASK: Match the food labels on the next page with the most likely food item that they represent.
Good luck!!! And, Yum!!!
_G__ 1. Starkist Albacore Tuna
_F_
2. Kraft Macaroni and Cheese
_A_
3. Nestle Chocolate Chips
_C_
4. Ruffles Reduced Fat Potato Chips
__B_ 5. Newman’s Corn and Roasted Pepper Salsa
_A_
6. Sturkey’s Creamy Balsamic Vinaigrette Dressing
_D_
7. Dole Pineapple Chunks
_E__ 8. Bush’s Great Northern Beans
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Station 4: Marvelous Macromolecules( 15 pts Total)
TASK: Match the description on the left with the structure on the right!
__J_ 1. Oleic Acid
__K_ 2. Trans fatty acid
I.
A.
__M_ 3. Omega-3 fatty
Acid
_L _ 4. Triglyceride
__C_ 5. Sucrose
B.
_D__ 6. Fructose
J.
__B_ 7. Lactose
__A_ 8. Aspartame
C
.
__P_ 9. Cholesterol
K.
__G_ 10. Amylose
__H_ 11. Amylopectin
D.
__I_ 12. Cellulose
_N_ 13. Tryptophan
L.
_F_ 14. Beta-carotene
E.
_E__ 15. Ascorbic
Acid
(Vit C)
E.
M.
F
.
O.
G. unbranched chains arranged in a helix
N.
15
P
H. branched chains
10
.
Station 6: Exploring Yeast Growth
TASK: Yeast, a very beneficial single-celled organism, has been used in the fermentation of foods for thousands of years - from
causing dough to rise to creating the unique tastes of beer and wine. A yeast population is affected by a number of factors, the
control of which is essential for optimal activity. In this simulated experiment, we will consider the effect of four factors on yeast
growth: pH, temperature, nutrient concentration and nutrient type. The yeast feeds on sugars and since one of the by-products of
the fermentation process is carbon dioxide, the reaction will be monitored by capturing the carbon dioxide in a balloon and
measuring its volume.
Exp 1: TEMPERATURE
5 g of sucrose, 4 g of rapid rise yeast, and 80 mL of tap
water were added to each flask. A balloon was placed over
the neck of each Erlenmeyer. Each flask was maintained at
a different temperature:
Exp 3: pH
5 g of sucrose, 4 g of rapid rise yeast and 80 mL of tap water
were added to each flask. The temperature was maintained
at 40oC. In each flask varying amounts of vinegar and
ammonia were added to change the pH.
Exp 2: SUGAR CONCENTRATION
4 g of rapid rise yeast and 80 mL of tap water were added to
each flask. The temperature was maintained at 40 oC. In
each flask, a different amount of sucrose was added.
Exp 4: NUTRIENT TYPE
4 g of rapid rise yeast and 80 mL of tap water were added to
each flask. The temperature was maintained at 40oC. In
each flask, 5 g of different sugars were added.
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Station 6: Exploring Yeast Growth (11 pts total)
1. Based on the simulated results, what are the optimal temperature, sucrose concentration, pH and nutrient for yeast growth?
(Calculate the “sucrose concentration” in percent by mass, assume that tap water has a density of 1.0 g/mL) (5 pts)
Temperature: ____________40oC______
pH: __________pH=7_______
Sucrose Concentration: _(30g/110g soln) x 100 = 27%___
Mass of soln = 80g + 30 g = 110 g
Nutrient: _________Fructose__________
2. Clearly, from the data, yeast cannot feed on milk sugar or lactose. How would the fourth experiment be different if, in the
lactose flask, some “Lactaid” or “Dairy Ease” was added? Lactaid or Dairy Ease are two commercially available supplements
that lactose intolerant individuals can take. (2 pts)
The lactose would be broken down into its monosaccharides, glucose and galactose, by the Dairy
Ease/Lactaid. The yeast could feed on the glucose for sure (and actually, the galactose too!). So, in the
experiment, a much greater volume of CO2 would be collected.
3. What do you suppose happens to yeast at high temperatures and/or extreme pH’s (high or low)?? (2 pts)
Since yeast is a single celled organism, high temps and/or extreme pH’s would probably kill the yeast
(denature it’s proteins!).
4. The data above does show total amount of CO2 released but does not reveal the reaction rate, how fast the reaction happened.
Based on what you know about sugars, sucrose and glucose illustrated approximately the same reactivity. However, which
sugar, sucrose or glucose, do you think the yeast would digest more quickly? Explain. (2 pts)
The yeast activity would probably be faster with the glucose. Glucose is a monosaccharide whereas
sucrose is a disaccharide. The yeast would have to take the time to break down the disaccharide
before it could feed on it.
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Station 5: General Questions ( pts total)
TASK: Please answer the following questions in the space provided on the left.
_D__ 1.
__A_ 2.
3. 328 or
320 Cal
_B_
4.
5. -Egg
(Lecithin)
- Oil
- Acid
(vinegar,
etc)
_A_ 6.
_C_
7.
__D_ 8.
__E_ 9.
10. See next
page!!
1. Which of the following is not an example of
a dietary fiber?
a. cellulose
c. lignin
b. pectin
d. glycogen
2. Which substance below is a common
thickening agent in jam making.
a. pectin
c. corn starch
b. lethicin
d. gelatin
6. Which of the following amino acids would
be considered NONPOLAR?
a
b.
3. Consider the food label from a Crispy Ranch
snack wrap from McDonalds.
.
c
Nutrition Facts
d.
Serving Size 4.1 oz (115g)
Servings Per Container 1
.
Amount Per Serving
Calories
???
Calories from Fat
Total Fat 16g
Saturated Fat 4.5g
Trans Fat 1g
Cholesterol 30mg
Sodium 780mg
Total
Carbohydrate 32g
Dietary Fiber 2g
Sugars 2g
Proteins 14g
Vitamin A 2%
Calcium 10%
7. What is the major protein in milk?
a. milk clabber
c. casein
b. rennin
d. Beta-lactoglobulin
???
% DV
25%
24%
8. Which of the following represents the
ZWITTERION form of the amino acid,
Alanine.
10%
32%
11%
6%
a. H2N—CH—COOI
Vitamin C 2%
Iron 10%
Calculate the total Calories. Assuming
fats produce 9 Cal/gram and proteins
and carbohydrates produce 4 Cal/gram.
Write the answer on the blank.
.
5. What are the THREE critical ingredients
needed to make mayonnaise? Write them on
the three blanks to the left.
4. A richly browned roast or steak with dark
grill marks tastes delicious due to the
chemical process known as browning.
Which description below would optimize the
browning process (Maillard reaction)?
a. Coat the meat with an oil.
b. Coat the meat with corn syrup and beef
stock.
c. Marinate the meat in pineapple juice.
d. Coat the meat with sugar and beef
stock.
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CH3
c. H3N+--CH—COOH
I
CH3
b. H2N—CH—COOH
d. H3N+--CH—COO-
I
CH3
I
CH3
9. Which statement below is FALSE about
soluble and insoluble fiber.
a. Both insoluble and soluble fiber is
not digestible by humans.
b. Fruit, such as apples and oranges, are a
good source of soluble fiber whereas
vegetables are a good source of insoluble
fiber.
c. Soluble fiber has been found to reduce
LDL cholesterol (the bad cholesterol).
d. Insoluble fiber helps prevent constipation
and colon cancer.
e. There are no false statements.
10. Draw a peptide bond between a
phenylalanine molecule (a) and a
glycine molecule (b). Label the
peptide bond. Draw answer to the
left in the designated box.
11. Many food
12.
a.
b.
c.
d.
e.
(a)
(b)
flavors have to undergo strict regulations and analysis before they are given GRAS status. What does GRAS
stand for??? Write your answer below.
Which statement is FALSE about partially hydrogenated oils. Partially hydrogenated oils…..
are used to extend the shelf life of processed foods.
have a cis-unsaturated structure.
are more dense and have higher melting points that the original veggie oil they came from.
are linked to heart disease in that they increase LDL and decrease HDL.
are produced by heating natural oils in the presence of hydrogen gas and a metal catalyst.
13. Let’s say you are baking homemade blueberry muffins and they keep coming out really chewy and dense. Which of the
following choices could explain what you are doing wrong with your bread recipe.
a. You are mixing too much.
b. You mixed too little.
c. You are using a flour with too low of a percentage of glutin.
d. The blueberries contain an enzyme which interferes with glutin formation.
14. Glutin is a special blend of proteins essential in the baking process. Which of the following statements is FALSE about glutin.
a. Glutin organizes itself into long flexible strands or sheets in kneaded bread.
b. Glutin is made up of two different proteins, glutenin for elasticity and gliadin for softness
c. Due to glutin’s nonpolar character, it repels moisture.
d. Wheat bread would have a higher glutin content than white bread.
15. a) Why is it that fresh pineapple should not be used when making jello but is very commonly used as a marinade for meats
like beef or chicken? Write your answer down below.
b) How would your answer to (a) be different or the same if you used pineapple from a can. Write your answer down below.
c) What is name of the “active ingredient” in pineapple that creates the situations above. There are two possible answers.
Write your answer down below.
Answers to 11 – 15.
11. ___Generally Regarded As Safe____
O
II
O
II
H2—CH—C—N—CH2—C—OH
I
CH2
I
Ring
12. ___B_
13. ___A_
*Answer to #10
I
H
Peptide Bond
14. __C__
15. a) Fresh pineapple has enzymes in it which break down (hydrolyze) proteins. Jello has gelatin
in it (collagen) which is a protein that gives jello its “jiggly” texture. The enzymes would break the
gelatin down and make it more watery (unable to set). With meat, on the other hand, breaking
down the proteins a little allows the meat to be more tender.
b) In the preparation of can pineapple, it is heated to very high temperatures. The heat
would likely denature the enzymes so they would not be effective. The jello would be able to set
just fine and the meat would not have that increased tenderness.
c) bromelin or papain
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