Section A: Research

Task:Gluten
formation is essential when making different types of dough. Investigate the
functional and chemical properties of a flour based dough, bread.

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To carry out this food investigation task, I will carry out
background research into the functional and chemical properties of flour based
bread dough and more importantly how gluten formation is essential when making
bread dough. I will use my previous knowledge of bread making to help inform my
research for this investigation.

Prior learning:

Ingredients used in bread making

Functions of ingredients

Strong plain flour

Strong plain flour has a high gluten content which is needed to make
bread and provides the bread with structure, texture and elasticity.

Water

Liquid (lukewarm so you don’t kill the yeast) is needed as it works
to bind ingredients together as well as activating the gluten.

Salt

Salt is used to flavour and strengthen the gluten.(no direct contact
with yeast as will kill it)

Yeast

Yeast is the raising agent which produces carbon dioxide through
fermentation.

Fat

Adds richness to the bread as well as extending its shelf life.

Sugar

Sugar is used to feed the yeast, making fermentation faster.

 

From my previous knowledge I know that in order for bread to
be made, it is essential for gluten to form properly and in order for that to
happen, certain ingredients need to be present.

Research:

Gluten is a protein, they
are large molecules made from amino acids, and formed from two proteins called
glutenin and gliadin. When the liquid is added to the flour, the proteins
combine together creating a gluten network. The gluten stretches to hold the
carbon dioxide bubbles which are produced by the yeast. Gluten is essential as
it gives bread dough plasticity and it allows the dough to be stretched and
shaped when being kneaded. Gluten holds the breads structure when raised and it
gives bread its structure.

The main factors affecting
gluten development are:

·        
Type of flour used

·        
Amount of water used

·        
Amount of salt added

·        
Mixing method

·        
Presence of fats

One
of the main factors affecting gluten development is the type of flour used as
some flours are higher in gluten in comparison to others, strong white flour
having the highest gluten content. In the table shown beside (sourced from Google
images) it shows that bread flour, otherwise known as strong white flour, has
the highest gluten content, making it the ideal flour for bread making as the
high gluten level will give the bread elasticity, texture and structure.

Another factor affecting gluten development is water as it
doesn’t exist until flour has liquid added to it. Water is the ingredient which
combines gliadin and glutenin, forming gluten. By adding more water you are
encouraging the development of gluten and when you add very little water, it
restricts glutens formation. Water is vital for gluten to form, but once the
gluten has become fully hydrated, if you continue to add more water the gluten
structures will weaken.

Another key ingredient used in bread making is salt as it
strengthens the gluten, therefore producing bread with a finer crumb. Salt also
controls the action of the yeast as well as developing the flavour of the
dough. Salt also gives the dough its elasticity, which in needs in order to
form properly. If there is not enough salt, the gluten structure won’t be
strong enough, but if there I too much it will hinder fermentation and absorb
more moisture.

Analysis/planning the investigation: I will test that in order
for gluten formation to occur using the right ingredients and right amount of
each is vital. I will test which flour is ideal for bread making, whether
increasing amounts of salt affect the bread formation and also whether
different amount of water added will affect the bread.

Hypothesis:
In order for gluten formation to happen fully, the use and amount of the right
ingredients is essential.

 

 

 

 

 

 

 

 

 

 

 

Section B:
Investigation

To test my hypothesis I am going to carry out three
investigations, each focusing on different ingredients which affect gluten
formation.

·        
Investigation
1: gluten ball experiment-showing which flour has the most amount of gluten
in each and therefore showing us the ideal flour for bread making.

·        
Investigation
2: amount of salt added to bread- showing how adding salt to dough
strengthens gluten formation.

·        
Investigation
3: amount of water added- showing that gluten needs to absorb the right
amount of water for gluten formation to happen fully.

Controls for each
investigation:

·        
Digital scale to measure all ingredients
accurately

·        
Dough’s kneaded and left to rest for same amount
of time

·        
All bread cooked at 200°c for 15 minutes, on the
same shelf and oven.

·        
Using random codes for each sample to avoid bias

 

Investigation 1:
testing the amount of gluten in different types of flour

Four different gluten balls were made, each with a different
type of flour and starch was extracted from each of the samples by washing the
samples under running water, and squeezing the starch out from each. After
washing away all the starch from each of the gluten balls, only the gluten was
left.

Each of the samples
were made with 50g of different types of flours and 25 ml of water. By weighing the balls at the end I found the percentage of
gluten in each of them by using the equation (x/50)/100

sample

ingredients

 

XXX
 
10% gluten

 This sample was made from strong wholemeal flour and produced
very little gluten and it took a very long time to remove all of the starch
present. The air pockets are very small and dense.

XXY
 
30% gluten

This
sample was made from plain flour
and it had large air pockets showing that there wasn’t much gluten remaining.

XYY
 
36% gluten

This
sample was made from strong white
flour and this flour showed the highest gluten content therefore making
it the most suitable for bread making as it allows it to rise with a good
structure.

YYY
 
0%  gluten

This
sample was made from gluten free flour
and there was nothing left after washing away all the starch, making this an
unsuitable choice for bread making as without gluten, brad wouldn’t be able
to form properly.

 

 

 

 

 

 

 

 

The most suitable sample is XYY as it has the highest
percentage of gluten, 36%,  which is
essential for doughs elastic property and structure.

Investigation 2:
adding different amount of salt to bread

Five samples were made in same way but with a different
amount of salt each time, as shown in the table below, with the other
ingredients remaining the same:

·        
125g strong white flour

·        
2g yeast

·        
½ tsp sugar

·        
75ml lukewarm water

XXX- control with no salt in the bread dough

XXX

XXY

XYX

YXX

YYY

0tsp salt

½tsp salt

1tsp salt

1 1/2tsp salt

2tsp salt

 

 

 

 

 

 

 

 

A testing panel was used to score each of the samples out of
5, by 3 tasters. 5 being the best and 1 being the worst. All bread doughs were
baked for 15 minutes at 200°c and doughs with less salt cooked better than ones
with more salt. Sample XXX had no salt and the taste wasn’t pleasant as shown
by the score of 5/15 for taste. Salt is needed to flavour the dough as well as
strengthening the gluten. Sample XXY was the ideal bread bun and scored the
highest, 30/45 as the bread was aerated.The salt strengthens gluten creating
bread with correct texture and structure as seen in the pictures.

Sample

appearance

total

texture

total

taste

total

Final total

XXX

5

5

4

14

3

2

3

8

2

1

2

5

27/45

XXY

4

4

4

12

3

2

2

8

4

3

3

10

30/45

XYX

4

3

3

10

2

3

2

7

2

3

2

7

24/45

YXX

3

3

2

8

1

1

2

4

1

1

1

3

15/45

YYY

2

2

2

6

1

1

1

3

1

1

1

3

12/45

 

 

sample

Weight(g)

XXX

87

XXY

90

XYX

96

YXX

99

YYY

103

As shown in the table the more salt added, the heavier the
weight becomes and in samples XYX, YXX and YYY you can notice that the doughs
become denser because the increase in salt tightens structure of gluten making
it too strong as well as slowing down enzyme activity and fermentation,
restricting the dough from forming the carbon dioxide it needs in order to rise
and fully develop.

Investigation 3:
adding different amounts of water to bread:

Five samples were made in the same way but with a different
amount of water added each time, as shown in the table below, with the other
ingredients remaining the same:

·        
125g strong white flour

·        
2g yeast

·        
1/2tsp sugar

·        
½ tsp salt

Sample

Amount of water(ml)

 

XXX

45

XXY

60

XYX

75

YXX

90

YYY

105

 

 

 

 

 

As discussed previously in my research, gluten doesn’t form
unless it comes into contact with water and from this experiment we can see
that as sample XXX and XXY are extremely dry and XXX especially had a terrible
texture 3/15 as gluten was not formed, therefore unable to create the
structures in bread. Sample XYX was the best sample, scoring a 33/45 from the
tasters because it had the prime amount of water needed, in this case 75ml. By
using 75ml of water it encouraged the gluten development whereas in samples YXX
and YYY there is too much water, causing the gluten structure to weaken making
the doughs very sticky and unappealing as well as creating more of an open structure.

 

 

Sample

appearance

total

texture

total

taste

total

Final total

XXX

1

2

1

4

1

1

1

3

3

2

2

7

14/45

XXY

2

3

3

8

3

2

2

7

3

2

3

8

23/45

XYX

4

3

3

10

4

4

4

12

4

3

4

11

33/45

YXX

2

1

2

5

2

1

2

5

2

3

2

7

17/45

YYY

1

1

1

3

1

2

1

4

2

1

1

4

11/45

 

 

Analysis and
evaluation:

From these investigations I can prove my hypothesis that the
use of the correct ingredients and amount of them affects gluten development.
When I carried out the gluten ball experiment it showed strong white flour had
the most gluten and the tasters preferred this sample the most, as shown in
sensory table.Although wholemeal flour may have nutritional properties, it
doesn’t have enough gluten like strong white flour does. In future I will know
that when I want to make bread rolls it should be made with strong white flour
in order for gluten to form and the bread be appealing, textured and tasty.

In addition, in experiment 2, I discovered that with too
little salt the bread has no flavour but with too much salt added it prevents
fermentation which causes the bread not to rise as much, making it denser and
heavier. As found from my sensory charts when there is too much salt added, the
taste, appearance and structure deteriorate and become unappealing. In future I
will know to always add the stated amount of salt as even half a tsp of salt
makes a huge difference in taste and structure.

In addition, I found that you must add the correct volume of
water as when there is too little, gluten can’t properly form, as gluten only
forms when liquid is poured on the flour. Also, if you add to much water it
will weaken the gluten structures making the bread less elastic and structured.
It is vital that you add the right amount of water for gluten to be hydrated.

All these investigations prove my hypothesis as without the
strong white flour, 75ml of water and ½ tsp of salt the bread would not be
formed properly and it is evident that gluten, which is essential in bread
making, needs the correct ingredients to form fully.