Name:
NFS 3321
Lab 6: Flour
Date:
Lab 6: Flour Study Questions
Results:
Show all recorded data collected during lab 6 in the appropriate charts below. (4 points)
Table 1. Physical and sensory characteristics of rapid rise bread.
Height
before
rising
(cm)
Height after
rising (cm)
Height after
baking (cm)
Crumb size*
(hole size)
Gumminess**
Crust
Color***
All Purpose
flour
Cake Flour
Bread Flour
Gluten Free
Flour
100% Whole
Wheat Flour
100% Whole
Wheat Flour + 2
Tsp. Vital Wheat
Gluten
*Crumb size (Scale: 1 = 1-2mm, very small; 3 = 0.5cm, medium; 5 = 1cm, very large)
**Gumminess (Scale: 1 = dry, not slick; 3 = semi slick, chewy; 5 = slick, slimy; sticky)
***Crust color (Scale: 1 = pale golden/tan; 3 = golden brown; 5 = dark brown)
Table 2: Determination of Gluten content of various flours
Variation
Flour
Initial Weight
Weight after
(g)
Rinsing (g)
1
All purpose
2
Cake flour
3
Bread flour
4
Gluten free
5
Whole wheat
6
Whole wheat
+ vital wheat
NFS 3321
Fall 2019
Weight after
Baking (g)
Lab 6 Study Questions
Name:
NFS 3321
Lab 6: Flour
Date:
1. Define the following terms as they relate to food science and bread baking chemistry (worth 1
point each):
A. Leavening agent
B. Gluten
C. Aluerone
D. Refined, enriched flour
E. Soft wheat
2. Which bread did you score highest in overall liking? Why did you give this bread this score?
Explain which sensory attributes score influenced your overall liking score (3 points).
3. Explain how the protein content of your assigned flour affected the volume of bread before
baking and after baking and how this affects its ability to produce a loaf of bread with welldeveloped texture, color and flavor (3 points).
4. What are the two major proteins that comprise gluten? How is gluten developed in dough?
What are the major ingredients involved in making bread, and what are their structural/chemical
purposes in bread? (5 points)
5. What substance in the washings creates the purple/black color when iodine is added? (2 points)
6. What is vital wheat gluten? What is it used for? (3 points)
NFS 3321
Fall 2019
Lab 6 Study Questions
Data Manager: Lab 6 (Flour)
(Document due to GA within 48 hours from lab section completion)
Table 1. Physical and sensory characteristics of rapid rise bread
Height
before
rising
(cm)
Height after
rising (cm)
Height after
baking (cm)
Crumb size*
(hole size)
Gumminess**
3
3
Crust Color***
All Purpose
Flour
3.5 cm
Cake Flour
3 cm
5 cm
6 cm
1
3
1
Bread Flour
4 cm
7 cm
9.5 cm
3
3
3
Gluten Free Flour
3 cm
3.5 cm
4 cm
3
3
3
1.5 cm
7 cm
9.5 cm
3
3
5
100% Whole
Wheat Flour
6.5 cm
11 cm
3
100% Whole
5.5 cm
1
3
Wheat Flour + 2 2 cm
6.5 cm
Tsp. Vital Wheat
Gluten
*Crumb size (Scale: 1 = 1-2mm, very small; 3 = 0.5cm, medium; 5 = 1cm, very large)
5
**Gumminess (Scale: 1 = dry, not slick; 3 = semi slick, chewy; 5 = slick, slimy;
sticky) ***Crust color (Scale: 1 = pale golden/tan; 3 = golden brown; 5 = dark
brown)
Table 2: Gluten Balls
Variation
Flour
Initial Weight (g)
1
All purpose
74 g
Weight after Rinsing
(g)
11 g
2
Cake flour
60 g
2g
0.66g
3
Bread flour
72 g
14 g
6g
4
Gluten free
76 g
62 g
53 g
5
Whole wheat
81 g
24 g
6
Whole wheat +
vital wheat
91 g
Weight after Baking
(g)
5g
17 g
38 g
27 g
Lab 5: Flour
Introduction
The study of Paleolithic refuse heaps has found cereal grains preserved through time. Many of
man’s earliest tools were developed for the removal of the husk of cereals to facilitate their
digestions. When the hunters settled down for good in areas rich in Graminaeae, or cereal
grains, they hollowed out mills and mortars in their caves in which to crush the grain from
around the surrounding countryside. The Phoenicians devised the notion of separating the grain
kernel from the rest of the plant and the Athenians developed methods for grinding cereal grains
into flour and baking bread. For six thousand years, the strength of nations depended on their
stocks of wheat, therefore; the significance of the slang term “bread” for money is obvious.
Gluten
Several thousand wheat varieties are grown in the US, with their most important distinguishing
characteristic being the content and quality of gluten protein they contain. Because gluten
proteins form the continuous phase in dough, they determine the dough properties. The gluten
protein is composed of two main groups of protein: gliadin and glutenin. When wheat flour is
mixed with water, gliadin and glutenin join together during kneading of the dough, creating the
gluten complex. Gliadin is extensible and sticky, while glutenin contributes elasticity and
cohesiveness as well as extensibility of the dough forming the cohesive, viscoelastic dough that
is a characteristic of wheat flour. It is the balance of these rheological properties that determines
bread making quality of a particular wheat. No other cereal flour forms a dough with a similar
viscoelastic character.
Gluten proteins are easy to isolate in a relatively
pure form because they are insoluble in water. By
working dough under a small stream of water, the
starch and proteins can be removed leaving a
rubbery ball of gluten. Gluten proteins are not
only responsible for this cohesive, viscoelastic
property of wheat flour dough, but also for the
dough’s ability to retain gas during fermentation
and for setting of the dough’s final structure
during baking.
http://www.perten.com/Products/Glutomatic/About-
Wheat flours are classified by their protein
gluten/
content, with hard wheat containing a higher
percentage of gluten protein and soft wheat containing less protein. Hard wheat typically has a
protein content of 11- 15% and is preferred for bread making in the US. Differences in protein
content and quality among different wheat varieties affect loaf volume and the firmness,
uniformity and soft wheat has a protein content of 8.5 – 9.5% and is preferred when baking
cakes, pastries, biscuits and cookies. Wheat is either white or red, with red wheat varieties
having more polyphenolics in the aluerone layer of the bran.
Lab 6: Flour
NFS 3321: FALL 2021
Page 1 of 9
Percent Protein (Gluten) of Various Wheat Flours
Flour
Protein %
Whole wheat flour
14
Bread flour
11
All purpose flour
10
Pastry flour
9
Cake flour
8
Gluten free flour
0
Milling
The milling process of breaks the wheat kernel down into the desired particle size to make a flour
of desired qualities. After tempering the wheat, where the moisture content of the wheat kernel is
raised, wheat undergoes several “breaks” or grinding and sieving steps to remove the protein and
starch rich endosperm from the bran and germ layer. Refined flour has been sieved to remove the
bran and germ layers from the endosperm during milling. This type of flour is then enriched or
fortified with B vitamins (folic acid, riboflavin, niacin, and thiamine) and iron prior to being
sold. Whole grain or whole wheat flour has had a percentage of the bran and germ layer put
back into the refined flour following grinding of these layers to a specific particle size according
to its end use by industry. To be labeled 100% whole wheat or whole grain flour 100% of the
bran, germ and endosperm has to be present in the flour.
Types of wheat flour
All Purpose, or AP flour is a blended wheat flour
consisting of hard and soft wheat containing an
intermediate gluten level which is marketed as an
acceptable compromise for most household
baking needs. AP flours can be sold as
unbleached, when peroxides are not used to
lighten the color of the flour. 100% whole wheat
flour contains 100% of the original kernel (bran,
germ endosperm). There are two different types
of whole wheat flours available: red whole wheat
and white whole wheat, differ according to the
color of their kernels. Soft flours are usually used
for making cake flour (the lowest in gluten) and
pastry flour (slightly more gluten than cake
flour). http://agcj.tamu.edu/407/sites/Sarvarian2/definition.htm
With the interest in consuming more whole foods such as
whole grains, some whole wheat breads
Lab 6: Flour
NFS 3321: FALL 2021
Page 2 of 9
may contain vital wheat gluten. Isolated from the protein rich endosperm, vital wheat gluten is
70 – 80% gluten and is used by commercial bakers to improve the texture and elasticity of whole
wheat and whole grain doughs. This is achieved by helping retain the gas and steam from baking
breads giving more volume to the baked bread.
Baking chemistry
Bread is typically made from flour, water, a fat or oil, leavening agent, sugar and salt. Other
ingredients may be added, but these are the main ones used. Water helps form the gluten
structure by bringing gliadin and glutenin together doing kneading of the dough. Sugar, either as
sucrose, dextrose or high fructose syrup is added to aid in the fermentation of the yeast to give
off carbon dioxide and ethyl alcohol. Sugar also helps in the development of flavors, retention of
water and browning of the crust. Fats or oils are added to soften the dough by coating the gluten
strands. Salt is added to help make the dough more elastic. Charged amino acids in the flour are
going to interact with the ions in the salt, helping the gluten strands line up, aiding in the
development of the bread’s texture.
Leavening agents creates a foaming action, incorporating air into the bread dough. Gluten
strands trap the carbon dioxide bubbles that are created and hold it so the dough will expand
during rising. Yeast is the most common used leavening agent in gluten containing breads.
Fresh yeast, or cake yeast, is a powerful leavener with a soft crumbly texture. It has a short shelf
life, lasting about two weeks in the refrigerator. Active dry yeast has been 95% dehydrated into
tiny granules. This intense process damages some of the cells while others become dormant, so
this yeast is “proofed” in warm water before adding it to the rest of the ingredients. This yeast
will start to bubble when it activates. Instant, or rapid rise yeast, is dehydrated to the same
concentration as active dry yeast, but by a gentler, less-damaging method. As a result, rapid-rise
yeast can be mixed directly into other ingredients without having to “proof” your dough.
References:
Brown A. 2011.Understanding Food: Principles and Preparation, 4th edition. Wadsworth
Cengage Learning. Belmont, CA.
Hoseney, R.C. Principles of Cereal Science and Technology. 1998. 2nd edition. Association of
Cereal Chemists, Inc. Minneapolis, MN.
Smith, J.S., Hui, Y.H. 2004. Food Processing Principles and Applications. 2004. Blackwell
Publishing. Ames, IA.
Toussaint-Samat, M. The History of Food. 2003. English Translation. Blackwell Publishers,
Oxford, England, UK.
Lab 6: Flour
NFS 3321: FALL 2021
Page 3 of 9
Lab 6: Flour
NFS 3321: FALL 2021
Page 4 of 9
Lab 6: Flour
NFS 3321: FALL 2021
Page 5 of 9
Experiment 1: Effects of flour type on dough formation
Each lab station will use a different type of flour using the same bread recipe. Prepare your
bread using the recipe below and then evaluate your bread type for loaf height before rising, after
rising, and the loaf height after baking. Also evaluate your bread for the characteristics listed
below.
Group 1: All Purpose flour
Group 2: Cake flour
Group 3: Bread flour
Group 4: Gluten free flour
Group 5: 100% Whole Wheat flour
Group 6: 100% Whole wheat flour + 2 Tsp. vital wheat gluten
Rapid rise bread Ingredients:
1 ½ C flour (your assigned flour)
3 Tbsp sugar
2 tsp salt
3 packages rapid rise yeast
2.5 C very hot tap water
3 Tbsp melted butter
3-4 C flour (your assigned flour) for dough development and kneading
1. Turn on the oven to preheat it to 300°F.
2. Mix together in a large bowl: 1 ½ C flour (your assigned flour); 3 Tbsp sugar; 2 tsp salt,
and 3 packages rapid rise yeast
3. Slowly add, stirring out any lumps: 2.5 C very hot tap water; 3 Tbsp melted butter
4. Add: 3-4 C flour (your assigned flour) for dough development and kneading on floured
board.
5. Knead for 10 minutes until dough is elastic, add extra flour if needed.
6. Cut dough into 2 even sections and shape dough into 2 loaves
7. Coat all sides of 2 loaf pans well with non-stick spray and place loaves into the coated
loaf pans. Measure the “height before rising” and note below in Table 1.
8. Place dampened towel over pans and let dough rise for 45 minutes on top of preheated
stove. Measure the “height after rising” following the 45 minutes.
9. After 45 minutes has passed, gently punch the dough in the middle of the pan once to
spread the carbon dioxide gas evenly.
10. Bake at 400°F for 45 minutes or until done. Check bread in oven around 30 minutes so
bread isn’t over-cooked. Measure the “height after baking”.
11. Allow bread loaves to cool 10-15 minutes and then evaluate ALL six different breads
using Table 1 below.
Lab 6: Flour
NFS 3321: FALL 2021
Page 6 of 9
Table 1. Physical and sensory characteristics of rapid rise bread
Height
before
rising
(cm)
Height after
rising (cm)
Height after
baking (cm)
Crumb size*
(hole size)
Gumminess**
Crust
Color***
All Purpose
Flour
Cake Flour
Bread Flour
Gluten Free
Flour
100% Whole
Wheat Flour
100% Whole
Wheat Flour + 2
Tsp. Vital Wheat
Gluten
*Crumb size (Scale: 1 = 1-2mm, very small; 3 = 0.5cm, medium; 5 = 1cm, very large)
**Gumminess (Scale: 1 = dry, not slick; 3 = semi slick, chewy; 5 = slick, slimy; sticky) ***Crust color
(Scale: 1 = pale golden/tan; 3 = golden brown; 5 = dark brown)
Be able to discuss which flour type has the greatest increase in volume and which has the least
increase in volume and why this has occurred. Which flour type has the best overall texture?
Experiment 2: GLUTEN BALLS – Determination of Gluten content of various flours
1.
2.
Variation
1
Flour (50g)
All purpose flour
Water (ml)
30
2
3
4
5
6
Cake flour
Bread flour
Gluten free flour
100% Whole wheat flour
30
30
30
30
30
100% White whole wheat + ½ tsp. vital wheat gluten
Mix the flour and water thoroughly in a small bowl with your hand.
Knead the dough for 10-15 minutes until gluten is well developed. WEIGH the dough ball
and record as the “initial weight” in the table below.
Lab 6: Flour
NFS 3321: FALL 2021
Page 7 of 9
3.
4.
Wrap the dough in a bag made of a several layers of cheesecloth.
Then wash the bag of dough in the sink under a slow stream of cool running water until the
water runs completely clear. Squeeze while rinsing/washing the dough to physically agitate
and remove the starch and protein.
5. Check for clarity by squeezing water out of the ball and into a beaker. Add 2-3 drops of
KI/I2. If a deep purple/black color appears with KI/I2, there is still starch present. Place KI
washing into waste container on back counter. Continue washing the dough ball until the
KI/I2 remains an orange/red color and does not change to purple/black. Do not start
checking until 15 minutes has passed.
6. Combine the leftover dough material in the dough bag. This is gluten. Notice the elasticity
of the product.
9. Remove the dough from the cheesecloth and roll into a ball. WEIGH the dough ball and
record as the “weight after rinsing” in the table below.
10. Bake at 450ºF at 15 minutes; lower oven to 300ºF and bake 20 minutes longer or until dry.
The oven should not be opened during baking.
11. Place all gluten balls from the class should be placed on a cookie sheet at least 6 inches apart
and placed in the same oven at the same time.
12. Observe the relative sizes of gluten balls. WEIGH the cooked gluten ball and record as the
“weight after baking” in the table below.
***Additional information for whole wheat variations only: When water runs over whole
wheat flour for about 20 minutes, the bran comes out in the cheesecloth. Wash the bran out of
the whole wheat dough by opening the cheesecloth and setting the dough ball aside. Rise all
of the bran flakes out of cheesecloth and off the surface of the dough ball. Once bran is
washed out of cheesecloth, close the cheesecloth around the dough ball again and continue
rinsing.
Table 2: Gluten Balls
Variation
Flour
1
All purpose
2
Cake flour
3
Bread flour
4
Gluten free
5
Whole wheat
Lab 6: Flour
NFS 3321: FALL 2021
Initial Weight
(g)
Weight after
Rinsing (g)
Weight after
Baking (g)
Page 8 of 9
6
Whole wheat +
vital wheat
Observations to Note:
What flour component is being washed out during rinsing? Which flours had the largest loss in
weight after rinsing and after baking? Why do you believe those flours lost more weight than
others?
Lab 6: Flour
NFS 3321: FALL 2021
Page 9 of 9

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