LAB 6: CARBOHYDRATES:
Part 1: Structure & Properties: Sweeteners, and Amylose
Purpose and Concepts:

Sweeteners:
o

Solubility:
o

Compare the structures and flavors of common sweeteners.
Compare the solubility of a monosaccharide, disaccharide, and polysaccharide.
Amylose:
o
o
Hydrolyze (break into smaller chains with water) starch (a mix of amylose and
amylopectin) into glucose using the enzyme (a protein that acts as a catalyst)
amylase found in saliva.
Test for the presence of Amylose using iodine (I2)
Reading: From “On Food & Cooking”
Carbohydrates: pp. 803-805
Sugars: pp. 652-656
Sweeteners: pp. 659-663
Starch: pp. 610-614
Supplies needed:
Test tubes with stoppers
Graduated cylinder
Droppers
Sweeteners to taste
Iodine/Potassium Iodide solution (I,KI) w/dropper
Solid Glucose
Sucrose
Corn Starch
Background Information:
Carbohydrates are the major components of plants, comprising 60 to 90% of their dry weight.
They are produced by the process of photosynthesis in green leaves.
The common small, or simple carbohydrates, are made of one (mono) or two (di) units. Glucose,
galactose, and fructose are simple monosaccharides that combine to form disaccharides
such as maltose, lactose, and sucrose.
Examples:
Monosaccharides
Disaccharides:
Glucose
C6H12O6
In fruits,
vegetables,
corn syrup
O
OH
O
H
C
H
H
C
OH
HO
C
H
OH
H
OH
H
H
OH
H
OH
H
C
OH
H
C
OH
H
C
H
Maltose
C12H22O11
CH2
In Malt/grains,
Potatoes
H
OH
C6H12O6
O
C H
H
In dairy,
sugar beets
CH2
OH
H
O
O
H
OH
OH
H
H
H
OH
HO
C
HO
H
OH
H
OH
OH
H
C
H
OH
H
O
O
H
OH
H
C
H
OH
O
H
H
OH
Lactose
OH
C12H22O11
OH
O
H
H
H
H
CH2
H
H
O
OH
Galactose
OH
O
H
O
OH
In Milk
OH
H
OH
H
H
OH
O
H
OH
H
H
H
H
H
H
Fructose
H
C6H12O6
In honey
Sucrose
OH
C H
C
O
C12H22O11
HO
OH
HO
C
H
H
C
OH
H
C
OH
H
C
O
H
OH
H
OH
In sugar cane
and sugar beets
CH117 Lab 6: Carbohydrates (F16)
O
H
HO
H
H
OH
OH
OH
H
OH
H
H
OH
HO
H
H
O
H
HO
O
OH
OH
H
OH
1
Complex Carbohydrates (Polysaccharides):
The complex carbohydrates amylose, and cellulose are long chain polymers of the simple carbohydrate
glucose.
Examples:
Amylose: Polymer of alpha-D-glucose
In Starches:
i.e. Rice, wheat, potatoes, beans
OH
OH
OH
O
H
H
OH
H
OH
H
H
H
OH
O
H
H
H
H
OH
H
H
OH
O
O
O
H
O
H
H
O
OH
n
Cellulose: Polymer of beta-D-glucose
OH
OH
OH
In Plant Fibers:
i.e. Cotton, wood, stems, leaves
H
H
OH
H
H
H
OH
O
H
H
O
H
OH
H
H
H
H
O
O
H
OH
O
H
O
O
H
OH
n
OH
Amylose, and its branched relative, amylopectin, are major components of starches, the energy storage
carbohydrates found in tubers and edible roots. Amylose and amylopectin are polymers of D-glucose in
which the anomeric carbon of each glucose unit is in the alpha () form.
Cellulose is plant structure material like that of wood, stems, and leaves. The major function of cellulose for
us is not as a source of glucose for energy, but rather as fiber to keep our digestive tract clean. Cellulose is a
polymer of D-glucose in which the anomeric carbon of each glucose unit is in the beta () form.
Sweetness:
Simple carbohydrates are called saccharides from the Latin term saccharum (sweet) because of their sweet
taste. Many of the small carbohydrates, mono and disaccharides, are used as sweeteners. They fit into the
taste receptor sites on our tongues and send the signal to our brains that we call sweet.
Artificial sweeteners are not usually carbohydrates and are not metabolized in the same way as natural
sugars. Artificial sweeteners mimic the shape of simple sugars and will fit into the same taste receptor sites
that natural sugars do and so send to our brains a similar “sweet” signal.
Examples of Artificial and Alternative Sweeteners:
OH
Sucralose
Saccharin
Cl
O
Cl
H
OH
“Splenda”
C12H19O11Cl3
H
O
H
H
OH
Aspartame
H
OH
C
NutraSweet®
“Equal”
CH
O
O
Stevia
OH
HO
O
OH
C
HO
O
HO
O
O
OH
OH
OH
CH2 O
H2N
H
S
“Sweet’N Low”
Cl
O
C14H18O5N2
N
HO
O
H
H
O
C7H5NSO3
H
CH2 O
NH
CH
C
H
O
OH
H
H O
CH3
HO
HO
O
H
H
OH
H
H
CH3
O
Using sucrose (common table sugar) as a standard (given a “sweetness value” of 1.00) the following list
shows the relative sweetness of common natural and artificial sweeteners.
Relative Sweetness: (compared to sucrose)
Lactose
Galactose
Maltose
Sorbitol
2
0.16
0.30
0.33
0.60
Glucose
Honey
Sucrose
Invert Sugar
Fructose
0.75
0.97
1.00
1.25
1.75
CH117 Lab 6: Carbohydrates (F16)
Aspartame
Stevia
Saccharin
Sucralose
180
300
450
600
Solubility:
Mono and Disaccharides are soluble in water since they have many exposed OH’s along their surfaces which
can easily hydrogen bond with water. Larger carbohydrates can still be soluble depending on the positioning
of their OH’s. If the OH’s are abundant on the exterior of a carbohydrate (even a large one) then hydrogen
bonding with water can occur and the carbohydrate can be made to dissolve in water. If, however, there is
internal hydrogen bonding within a carbohydrate, or coiling that may prevent water from hydrogen bonding
to the OH’s, then the carbohydrate will not dissolve in water.
Starch granules, tightly coiled strands of amylose and amylopectin, are not soluble in water at ordinary
temperatures and so are convenient forms in which to store the plant’s excess energy supplies. Roots and
seeds are the organs in which starch is usually concentrated. Forms of amylose starch can be made to be
soluble by heating in water so as to disrupt the solid packing of the strands. The coils unravel into long
strands of amylose which have OH’s more exposed to hydrogen bond with water. Not only are the uncoiled
strands more water soluble but they can also tangle with each other to form gels. We often use these
“unraveled” starch strands as thickeners in cooking or for stiffening fabrics.
Although there are some forms of soluble fiber (like in oatmeal), most plant cellulose is not water soluble
even with heating. Cellulose strands have a lot of internal hydrogen bonding with themselves and each other.
They form tight, twisted cables that make very strong structure material that does not unravel even in hot
water.
Chemical Reactivity:
Colorization of Iodine: Test for Polysaccharides:
Amylose, the unbranched chain polymer of -D-glucose in starch, coils
into tight spirals. Elemental iodine, I2, which is normally yellow-brown in
color, will fit inside the amylose coil and complex with the OH’s inside the
spiral. The resulting amylose-iodine complex is a deep blue-black color.
I2
I2
I2
(yellow/brown)
I2
I2
I2
Iodine, I2, is commonly used as a test for the presence of amylose starch.
Legal U.S. dollar bills made from a linen fabric will not react with iodine;
however, the mark of the iodine pen on bills made from starched paper
will show the characteristic dark blue sign of a counterfeit.
Amylose/I2 Complex
(blue/black)
Amylose Helix
Hydrolysis: Each bond connecting monosaccharide units (the glycoside bond) can be broken by
hydrolysis; the reaction with water in the presence of a catalyst. Disaccharides can thus be hydrolyzed into
two monosaccharides. Polysaccharides can be hydrolyzed into shorter chains or further into simple sugars.
In the laboratory we can catalyze sugar hydrolysis reactions with acid, or we can use catalytic enzymes that
are specific for each carbohydrate.
Sucrose is hydrolyzed into a 50:50 mixture of glucose and fructose by catalysis with the enzyme, sucrase.
Maltose hydrolyses into glucose with maltase. Lactose hydrolyses into galactose and glucose with lactase.
OH
OH
O
H
H
OH
H
HO
H
H
O
H
HO
O
OH
OH
H
OH
H
H+, H2O
or
Sucrase
O
H
HO
OH
H
OH
H
H
+
H
OH
OH
Glucose
Sucrose
OH
O
H
OH
HO
H
OH
H
OH
Fructose
Amylose and amylopectin are easily hydrolyzed into shorter chains of glucose called dextrins which are then
further hydrolyzed into the disaccharide maltose and then to glucose (blood sugar) itself. In our bodies the
hydrolysis of starches in digestion is catalyzed by the enzymes amylase and maltase. People vary in the
amount of amylase in their saliva or urine.
Starch
(Amylose, Amylopectin)
H+, H2O
or
Amylase
Dextrins
H+, H2O
or
Amylase
Maltoses
H+, H2O
or
Maltase
D-Glucoses
The hydrolysis of cellulose can be catalyzed in the laboratory with acid or by the enzyme cellulase found in
certain bacteria. The human body does not contain the enzyme cellulase and so cannot convert cellulose into
glucose for use as an energy source. Therefore, the long chain of cellulose stays intact for use as fiber.
CH117 Lab 6: Carbohydrates (F16)
3
Procedures:
Notes:
1There
Actions:
I. Sweetness:
1. Taste a small sample of each sugar or sweetener available and
rank them in order of sweetness.1 (#1 being the sweetest.)
2. On the report sheet, record the predicted order of sweetness
from your textbook. Compare your taste results with the
predicted order and report your observations. 1
II. Solubility:
1. Obtain 5 stoppered test tubes and label them 1-5.
2. Into each tube place about 5 mLs water. 3
3. Place the following in the tubes:
 Into tube #1 put nothing. This will be the control. 7
 Into tube #2 put an unpopped-popcorn-kernel sized scoop2 of


glucose (a monosaccharide).
Into tube #3 put an unpopped popcorn kernel sized scoop of
sucrose (a disaccharide).
Into both tubes #4 and #5 put an unpopped popcorn kernel scoop
of corn starch (a polysaccharide).
4. Stopper and shake each tube to mix. Record the solubility of each
(S = soluble, I = insoluble, and PS = only partially soluble).
5. Carry all of these samples on to use in the next section (Part III).
III. Hydrolysis: Reaction of Amylase with Starch
1. Obtain 1 more clean test tube. Into this tube
 spit enough saliva to measure about 1 inch.
2. Pour the saliva into tube #5 that contains corn starch.
3. Set tubes (#1 through #5) aside for about 20 minutes (longer is OK
so go ahead and work on other parts of the lab then come back to this.).
Colorization of Iodine, I2: Test for Amylose:
4. After at least 20 minutes:
 Into sample tubes #1-5 add 2-3 drops of Iodine, Potassium
Iodide (I2, KI) solution.8 If needed you may swirl or stopper
and shake each to mix.
 Observe and record the color of all samples and note the
presence of amylose. 9
4
CH117 Lab 6: Carbohydrates (F16)
will be a variety of results
here as personal tastes vary. Do
your tastes match the predicted
order
or
are
there
discrepancies?
2Use
the same size sample for
each item so you can compare
solubilities.
3This
measurement does not
need to be exact. Make the first
measurement with a graduated
cylinder and then estimate the
others by comparing the levels
with that of the 1st tube.
6This
experiment could be done
with starch in any form even
crushed crackers or bread
crumbs.
7A
control sample should show
no reaction. We use it as a
reference to which we can
compare the others to tell if a
reaction has taken place.
8Iodine,
I2, turns dark blue if it
complexes with the spiral form
of amylose in starch.
9Not
all people have the same
amount of amylase in their
saliva. Check the samples of
other class members to see how
their amylase reacted.
LAB 6: CARBOHYDRATES:
Part 2: Composition of Flour: Gluten
Purpose and Concepts:

Composition of Flour:
o
o
o
Isolate the gluten protein from various types of wheat flours.
Compare the protein content of common wheat flours.
Make gluten balls or Seitan.
Reading:
Carbohydrates: pp. 803-805
Starch: pp. 610-614
Gluten: “On Food & Cooking” pp. 521-525, 536-538, and 468
Supplies needed:
Gluten Balls (Seitan)
*400 mL Beaker or bowl
*measuring cups
Running Water
Baking tray or cookie sheet
Oven
Optional: Seasoning for seitan such as:
Soy sauce or Garlic powder
(~1/3 c) each of a variety of wheat Flours to test such as:






whole wheat flour
bread flour
all-purpose flour
pastry flour
gluten flour
cake flour
Background Information:
Gluten:
Gluten is a protein complex formed from the proteins glutenin and gliadin found in wheat and related
grains such as barley and rye. It gives elasticity to dough, which helps it rise, keep its shape, and creates a
chewy texture. Without it, there would be nothing to hold the gases that makes bread rise. You might
think of gluten as the rubber of a balloon: The stronger it is, the more gas it can hold.
High-protein flour will make a dough with strong gluten, good for hearty yeast breads. However, for
many baked goods, like pastries and pie crusts, pastry chefs want to avoid gluten development so prefer
low-protein flours that yield delicate, tender doughs.
In baking, gluten is mainly used for the light texture and distinct taste it gives bread. But as a protein it is
also nutritious. When flavored it becomes a vegan “meat” (called seitan) and it is a common chewy
protein addition to vegetarian or vegan stir-fries and stews.
CH117 Lab 6: Carbohydrates (F16)
5
Notes:
Procedures:
1
Actions:
IV. Gluten Content in Flour:
1.
Tare a large beaker or small bowl on your gram
balance.
The amount of flour does not have to be exact but you
do need to know exactly how many grams of flour you
have to the accuracy of your balance so that you can
eventually determine the percent (%) gluten in the
flour.
2
1
2.
Measure into the tared beaker about 1/3 cup of
flour2 to the accuracy of your balance.
3.
Have ready but do not yet add about ¼ cup (60
mL) water.
4.
Add a little of the water to the flour at a time,
mixing as you go to create a dough that can be
worked with your hands (not too dry but also
not too sticky). (You may not need all of the 60 mL of
water or you may need more. If you need more then
adjust with a little more water a little at a time.)
5.
6.
3
Knead the flour/water mixture until it forms a
soft, rubbery ball of dough (usually about 8-10
minutes). Make note of the texture, flexibility,
and elasticity.
Put the kneaded dough into a plastic sandwich
bag and let the dough ball sit for at least 10
minutes. (Longer is OK so feel free to work on
other parts of your experiment while you wait.)
4
7. Hold the dough under a gentle flow of cold
water at a sink faucet while gently squeezing to
allow the starches and other water soluble
components to dissolve and wash away.5 Be
careful not to let the dough disintegrate.
8. Once no more starch appears to wash away6,
press out any extra water and place your gluten
ball on a baking sheet. Note the changes in size
and texture.7
9. Bake8 the gluten balls in an oven at 232oC
(450oF ) for about 15-20 minutes.
A variety of wheat based flours may be used and the
amount of gluten in them compared. Possible flours to
use could be:
Theoretical % Gluten
70-85
 gluten flour
15-16
 spelt
11-15
 whole wheat flour
13
 semolina flour
12-13
 bread flour
11-12
 all-purpose flour
8-9
 pastry flour
7-8
 cake flour
3
Kneading the dough and then letting the dough rest
causes the two proteins in wheat flour, gliadin and
glutenin, to stretch and then combine to form gluten.
4
Try cupping your hands around the ball and squeezing
gently to remove the starch. With low-gluten cake or
pastry flours, you may want to put the dough in
cheesecloth in order to hold it together.
5
You’ll notice the water turning milky as it washes
away the starch.
6
You’ll know the starch is gone when the wash water
no longer becomes milky.
7
Your dough ball will become a gummy, slimy network
of gluten protein strands.
8
Before baking you could flavor the gluten with soy
sauce, ginger, garlic, seaweed, or other spices to make
the vegan “meat” called seitan.
9
A qualitative comparison could be made just by
comparing the sizes of the gluten balls produced. A
quantitative comparison can be made by determining
the percent gluten in each type of flour. To determine
the percent gluten measure the mass of the flour used
and the mass of gluten produced then calculate as
follows:
10. Weigh the dried and baked gluten ball and
determine the % gluten in your flour. 9
11. Compare the amount of gluten in the various
flours tested by the class.
12. Analyze the flavor and texture.
6
CH117 Lab 6: Carbohydrates (F16)
Mass gluten obtained x 100 = % gluten
Mass Flour Used
LAB 6: CARBOHYDRATES:
Part 3: Dehydration; Caramelization
Purpose and Concepts:

Dehydration:
o Dehydrate (remove water) carbohydrates with acid and with heat.
o Apply dehydration and solubility principles to making caramel.
Dehydration and acid/base leavening:
o Apply caramelization and chemical leavening to making peanut brittle.

Reading: From “On Food & Cooking”
Caramelization: pp. 656-657 and 778
Safety:
Concentrated sulfuric acid (18M H2SO4 aka battery acid) will be used to dehydrate sucrose.
Avoid getting sulfuric acid on your skin but if you do then wash immediately with soap and water. Wear
safety goggles at all times when working with concentrated acids or bases.
Supplies needed:
Safety Goggles
Test tubes with stoppers
Beakers (50, 2x250, 2x400 mL)
Measuring equipment
Stirring spoon or stick
Hotplate or Burner
Concentrated Sulfuric acid (18M H2SO4)
Sucrose
Aluminum Foil
Thermometer
Salt
Butter
Peanuts
Baking Soda
Vanilla
Dehydration: When carbohydrates are either heated or reacted with acid, H’s and OH’s combine and leave
as water, HOH. As water molecules begin to escape the carbohydrate begins to turn yellow, then brown, and
then eventually black.
Caramelization
O
O
O
O
C
C
H
C
H
C
H
OH
H+1 or
Heat
C
C
H
C
HO
C
HO
C
C
H
C
OH
H
C
C
C
H
H
C
OH
H
C
OH
H
C
OH
H
C
H
H
C
H
OH
H
H
HO
H
OH
OH
O
H
C
OH
C
C
H
C
OH
H
O
C
C +
complexes
(black)
O
H2O's
O
H
OH
Possible Dehydration Intermediates
(yellow to brown)
O
O
O
As paper (a cellulose product processed with acid) ages it slowly dehydrates and turns yellow. Acid acts as a
catalyst to make the dehydration faster. Scrap-bookers prefer “acid-free” paper that will stay white longer.
Caramelization occurs when carbohydrates (small or large) partially dehydrate and decompose with heat
or acid to give flavorful molecules.
Loss of some of the OH’s from sucrose, glucose, and fructose results in a caramel brown color and also gives
the characteristic taste of browned caramel candy.
CH117 Lab 6: Carbohydrates (F16)
7
Loss of some of the OH’s from amylose in starch also results in browning. The word “roux” is French for
“red” and at some point in history came to mean flour that had been cooked long enough to change color.
Flour undergoes browning reactions when cooked giving flavorful dehydrated molecules in much the same
way as the caramelization process.
A common method for making sauces and gravies uses the formation of a “roux”. Flour or starch (complex
carbohydrate; amylose and amylopectin) is heated in oil until it browns. Water or milk is then added and the
mixture heated to a thick sauce.
If all of the OH’s on a carbohydrate are removed as water then all that remains of the compound is black
carbon charcoal. This phenomenon is observed when food or wood is burned to blackness.
Notes:
Procedures:
10Concentrated
Actions:
V. Dehydration / Caramelization:
A. Dehydration of Sucrose with acid (Instructor Demo)
1. Into a 50 mL beaker (non-food) pour solid sucrose up to about
the 25 mL mark.
2. Move the beaker of sucrose to the fume hood. Pour 10 mLs
concentrated Sulfuric Acid10 onto the sucrose and observe the
color, and chemical changes. Record all observations.
B. Dehydration of Cellulose with acid (Instructor Demo)
3. Place a drop11 of concentrated Sulfuric Acid on a piece of paper
towel. Record your observations.
C. Caramel12: Dehydration of Sucrose with heat
1. Prepare a piece if parchment paper or Al foil for use in step 4.
2. Into a 150 or 250 mL food beaker mix about 20 mLs of solid
sucrose and 10 mLs water.
3. Without stirring observe the color changes, odor, chemical
changes, etc. as you gently heat the sucrose over a hot plate or
laboratory burner. 13 Do not let the sucrose burn. 14
4. Remove from heat when the sugar turns to a golden caramel
liquid15 and quickly and carefully (use a pot holder as the beaker
is hot) pour your hot liquid caramel, making swirls or designs,
onto a piece of parchment paper or aluminum foil.16
5. Record all observations on your report sheet.
6. Clean the beaker by boiling hot tap water in it until the caramel
is dissolved enough to be washed out.
8
CH117 Lab 6: Carbohydrates (F16)
Sulfuric Acid is
dangerous to your skin, eyes, and
clothes.
Do not breathe the
vapors.
Wash with copious
amounts of water if contacted.
11Wiping
the con H2SO4 from a
dripping container would get the
drop of acid you need on the
paper towel.
12Caramel
syrups, sauces and
candies sometimes use brown
sugar and also contain cream,
evaporated milk, or sweetened
condensed milk.
13Microwaving
½ c sugar + ¼ c
water for 3-5 minutes also works.
14Notice
any steam, water vapor,
which may come from the
reaction. The high heat forces the
O’s and H’s to leave the
carbohydrate as water. Once all
of the O’s and H’s have left as
water it is just the C’s, charcoal,
which would be left behind.
15Caramel
can burn very quickly
so remove earlier rather than
later.
16You
could lay a wooden stick on
the foil and make swirls over the
end of the stick to make a caramel
lollipop.
VI. Partial Thermal Degradation of Carbon Dioxide
foamed saccharides with protein inclusions: 17
17Also
known as Peanut Brittle
18Solidified
1. Read through the following procedures and have your Al (aluminum)
foil, pot holder (or folded paper towel) and all ingredients measured,
set aside and ready before you begin combining and heating.
butter
2. Lightly grease a one-foot square of aluminum foil using a pad of
paper towel coated with solidified mixed esters18 and set aside.
20Sucrose
3. Weigh into a 400 mL tared beaker:
 30 g of a commercial glucose/fructose solution19
mixed esters =
19A
Glucose/Fructose solution
= Corn syrup
21H2O
= table sugar
= water
20NaCl
= table salt
21Protein
4. Add to the beaker containing the corn syrup:
 40 g of sucrose20.
 10 mL H2O21.
5. Heat this mixture slowly on a hot plate. Stir constantly until all is
dissolved. Bring to a boil on gentle heat. (Use as little heat as possible
to maintain boiling to avoid burning the saccharides.)
pellets containing
arachin, conarchin and oleiclinoleic glycerides = peanuts
22
NaHCO3 (sodium bicarbonate
= Baking soda
234-hydroxy-3-methoxy-
benzaldehyde = vanilla extract
6. Add:
 5 g of solidified mixed esters18
7. Continue to heat and stir using a wooden spoon or stir stick.
8. When the temperature of the saccharide mixture reaches 138 °C, add:
 0.15 g of NaCl20
 30 g of protein pellets21 contianing arachin, conarchin and oleiclinoleic glycerides
9. Continue to gently heat and stir while monitoring the temperature.
10. When the temperature reaches 154 °C, remove the mixture from the
hot plate and place the beaker on a paper towel near the prepared Al
foil. Remove the thermometer.
11. While one partner holds the beaker and is prepared to stir vigorously,
have the other partner add
 1.8 g of NaHCO3 (sodium bicarbonate)22
 14 drops (about 1 mL) of 4-hydroxy-3-methoxy-benzaldehyde23
12. Stir vigorously until the mixture stops foaming then pour the mixture
on the Al foil and let it spread out.
13. When cool, break up the product and consume.
CH117 Lab 6: Carbohydrates (F16)
9
10
CH117 Lab 6: Carbohydrates (F16)
Lab 6: Carbohydrates Part 1: Properties
Name___________________
Partner_________Date___
Report:
I. Sweetness: Rank in order of sweetness from 1-6 (#1 being the most sweet)
Fructose Glucose Sucrose Aspartame Saccharin Stevia
Sucralose
Order of
Sweetness
(Your Taste)
Order of
Sweetness
(From Text)
Compare
your taste w/
text:
II. Solubility:
1. Glucose
2. Sucrose
3. Starch (Amylose)
Solubility
(cold)
Conclusion/Explanation/Analysis: Discuss pertinent observations.
Why did these results occur? Explain any Anomalies.
4. On the given structure: A) Label any - O’s and + H’s. B) Show (using
how water molecules can
hydrogen bond to glucose. (Show at least 6 waters H-bonding with glucose):
H
H
H
O
……..)
H
C
C
H
H
O
O
H
C
H
C
O
O
C
C
H
O
H
H
H
III. Hydrolysis and Colorization with Iodine, I2:
1. Control
Observation
Color
2. Glucose
Color
3. Sucrose
Color
4. Starch
Color
5. Starch + Saliva
(Amylose)
Amylose?
(Amylose + Amylase)
Color
Amylose?
Yes or No
Yes or No
(circle one)
(circle one)
(> 20 min w/ I2)
Summary/Explanation/Analysis: Why did these results occur? Explain any Anomalies.
___ 1.
Why is there no blue color with Iodine when amylose reacts with saliva?
A. Amylase in saliva causes the amylose chain to uncoil so Iodine is not trapped.
B. Amylase in saliva reacts with iodine causing it to be unable to complex with the amylose coil.
C. Amylase in saliva causes the amylose chain to break into short chains and then into glucose which does not
coil and so does not trap iodine.
D. Amylase in saliva will replace the I2 in the amylose coil and so remove the color.
CH117 Lab 6: Carbohydrates (F16)
11
Lab 6: Carbohydrates Part II; Gluten
Report:
IV.
Name___________________
Partner_________Date___
Gluten from Flour:
Type of flour used:
__________________
Grams of flour used:
__________________
Results:
Observations: Describe what you observed in the process of forming and
isolating gluten.
Mass of Gluten you obtained:______________ X100 =
Mass of flour you used:
% gluten
Comparison of Gluten from Flours: Class Results
Flour
Type
(~1/3 cup)
Students
Theoretical
Rank:
Rank in order of
gluten content
based on textbook
(#1 being highest)
Mass of gluten (g) x 100 = % Gluten
Mass of flour(g)
Experimental
Rank:
Rank in order of gluten
content based on class
results (#1 being
highest)
Description
(Appearance,
size, flavor)
all-purpose
flour
whole
wheat flour
cake flour
Semolina
flour
Spelt
Flour
Conclusions: Compare and Contrast. Evaluate the % Gluten in the various flours. Compare theoretical
to experimental results.
Analysis: Critique the experiment.
What worked well and what might be improved. For example be specific about
what ways you might change the procedures in order to make a better gluten ball.
12
CH117 Lab 6: Carbohydrates (F16)
Lab 6: Carbohydrates Part III; Dehydration
Report:
Name___________________
Partner_________Date___
V. Dehydration: Caramelization with Heat and Acid:
Observations
A. Acid on Sucrose
B. Acid on Cellulose
Conclusion/Explanation/Analysis: Why did these results occur?
C. Heat on Sucrose
Give an explanation that covers all of these results.
VI. Peanut Brittle:
Observations: How did it look? Taste?
Reaction: Complete the reaction of Sodium bicarbonate (NaHCO3 ) with a typical acid (HA) as in the sugars to cause the foaming.
Conclusion/Explanation/Analysis: Describe what was happening chemically in
A) the process of caramelization of your saccharides
B) the formation of foamy peanut brittle.
Post Lab Exercises: More than one answer may be required. Give all correct
answers.
_____1. Which of the following are not carbohydrates?
A. fructose
B. glucose
C. aspartame
D. cellulose
CH117 Lab 6: Carbohydrates (F16)
E. saccharin
F. sucrose
13
_____2. Amylose differs from amylopectin in that _____
A. Amylose is digestible by humans but amylopectin is not.
B. Amylose is branched but amylopectin is a straight chain.
C. Amylopectin is branched but amylose is a straight chain.
-D_____3. The major component of paper is _____
A. amylose
B. cellulose
-D-glucose.
C. glucose
D. cellulite
_____4. Cellulose is essential in human nutrition because _____
A. it is undigestible so remains as long strands that act as fiber.
B. it can be hydrolysed to form glucose which will be used as blood sugar.
C. it is undigestible and so acts as filler in food products so we can avoid calories.
D. it can be digested to form glucose which will be used as blood sugar.
_____5. What is most important in making a carbohydrate water soluble?
A. The ratio of O’s relative to C’s in the structure.
B. The ratio of OH’s relative to C’s in the structure.
C. The ratio of OH’s available to hydrogen bond with water relative to C’s in the structure.
D. Monosaccharides are water soluble but the others are not.
_____6. Why do crackers (high in amylose) have the potential to taste sweet after chewing in your mouth?
A. Amylose is naturally sweet tasting.
B. Amylose reacts with amylase in saliva and produces glucose which tastes sweet.
C. Amylose reacts with sucrase and produces sweet tasting sucrose.
_____7. The gaseous substance that is driven off of sucrose when it is heated is __
A. CO2
B. SO3
C. CH4
D. H2O
_____8. The gaseous substance that is driven off of sucrose when it is reacted with acid is __
A. CO2
B. SO3
C. CH4
D. H2O
_____9. The black residue left over after complete dehydration of a carbohydrate is ___
A. C
B. SO3
C. HSO2
D. H2O
_____10. Why does a solution made of starch get thick when heated in water?
A. Granules of starch uncoil to give long strands that tangle into a gel.
B. Starch granules stack in an organized pattern that makes the mixture solid.
C. Starch is insoluble so just forms complexes of suspended solids which thicken the mixture.
Vocabulary: Match each word with the best phrase to which it relates.
A. None of these
___1. Hydrolysis
B. A polymer of glucose having alpha-1,4 links
___2. Dehydration
C. A polymer of glucose having beta-1,4 links
___3. Roux
D. Removing water
___4. Caramelization
E. A vegan meat substitute made from gluten
___5. Starch
F. An enzyme that breaks starch into glucose units
___6. Gluten
G. Turns blue when coiled around iodine
___7. Amylose
H. Starch that has turned brown by being decomposed and dehydrated with heat.
I. Splitting apart into smaller pieces with water
___8. Amylase
J. The ability to dissolve
___9. Solubility
K. The decomposition and dehydration of sugars
___10. Seitan
L. An elastic protein complex made from gliadin and glutenin.
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CH117 Lab 6: Carbohydrates (F16)