The influence of sugar on the rising of bread.
Bonnie, M. , Geluk, I., & Vlaar, J.
C. Huygens College, The Netherlands.
Received February 2010
Summary.
Bread is a basic product in our diet. In Western society most people eat bread every day. One of the
increasing health problems in western society is that people are gaining too much weight. Bread is
seen as one of the more healthy products, but what a lot of people don’t know is that sometimes
more sugar is used in it than necessary. So we decided to examine the influence of sugar in
combination with yeast in bread. Yeast is an eukaryotic organism which converts sugar into carbon
dioxide and water. This process is called aerobic fermentation. We looked at the rising and the height
of the bread after baking.
Introduction
Experimental procedure and approach
Yeast converts sugar and oxygen into
carbon dioxide and water.
We started with a recipe that we got from the
internet. (bibliography 3 and 4)We made six
different doughs. In each dough we used a
different amount of sugar.
Each dough contained 250 grams of flour, 150
mL of water, 5.0 grams of sunflower oil, 5.0
grams of salt and 7.5 grams of yeast.
C12H22O11 + H2O
C6H12O6 + C6H12O6
Sucrose
glucose
fructose
The fermentation of glucose/fructose
C6H12O6
2 C2H2OH + 2 CO2
The oxidation of glucose/fructose
C6H12O6 + 6 O2
6 CO2 + 6 H2O
We started with sucrose, which converted
with water into glucose and fructose. In
anaerobic environment glucose and fructose
convert into alcohol and carbon dioxide. In our
experiment there is a aerobic environment,
which causes the glucose/fructose to convert
with oxygen into water and carbon dioxide.
The carbon dioxide is trapped within the
dough. This causes the dough to rise.
We expect that the rising of bread
depends on the amount of sugar, but that
there is also a maximum amount. We expect
this because for one reason the yeast won’t
have the time to convert all the sugar.
Preparation:
We mixed the salt and flour in a bowl and we
made a hole in the middle. Then we put the
right amount of sugar in each beaker. After
the sugar was dissolved, we put the yeast in
each beaker at the same time and we stirred
the mixture till the yeast was also dissolved.
Then we poured it into the holes. After that
we put a damp tea towel over the bowls and
put them near a radiator for 45 minutes
(picture 1). We put it near a radiator because
this is a warmer spot and will speed up the
fermentation.
After 45 minutes we put the oil into
the holes filled with the yeast mixture.
We kneaded this with the flour into a ball.
Then we put the damp tea towels back on the
bowls. We let the bowls stay at room
temperature for two hours. (picture 2)
When the two hours were over we
kneaded the dough quickly and separated
each portion of dough into four pieces with
the same weight. Each piece went into a
cupcake form. We labeled the dough with
different colors. We let them rest for one
hour in the cupcake form. (picture 6)
Then we put them in an oven that was preheated to 220⁰C (493 K). We placed a bowl of
cold water at the bottom of the oven. The
doughs stayed there for 30 minutes.
When the buns were done we
weighed them on a scale. Then we measured
the height with a knitting needle. We oiled the
needle with the sunflower oil and pricked the
bread at its highest point. After we pulled the
needle out we measured the height with a
ruler.
Because we only had one cupcake form we
only had room for 3 buns in the oven. So we
decided to start with doughs 1, 2 and 3. One
hour later we started making doughs 4, 5 and
6 which also means we baked them an hour
later .
size of the holes, but we couldn’t see a
difference. (picture 5)
Table 1.
Dough
Amount of
sugar. (gr)
Dough 1
0.00
Dough 2
2.50
Dough 3
5.00
Dough 4
7.50
Dough 5
10.00
Dough 6
20.00
Results
After the first 45 minutes we noticed
that dough 1 had less foam then the other
two. After the 2 hours of rising, dough 1 had
less volume. When we put the dough into the
cupcake form the buns doubled in size after 1
hour. After the baking we noticed a difference
in color. Higher amounts of sugar caused a
darker brown color.
After we had baked the buns we cut
them open and looked at the amounts and
Figure 1.
height of bun
(cm)
1.
2.
3.
4.
1.
2.
3.
4.
1.
2.
3.
4.
1.
2.
3.
4.
1.
2.
3.
4.
1.
2.
3.
4.
7.5
7.2
7.4
7.5
7.5
7.5
7.5
7.6
7.5
7.6
7.7
7.6
8.0
7.7
7.8
7.7
8.2
8.3
8.1
8.5
8.5
8.2
8.6
8.2
Average mass
and maximum
error (cm)
7.4 ± 0.2
7.5 ± 0.1
7.6 ± 0.1
7.8 ± 0.2
8.3 ± 0.2
8.4 ± 0.2
Table 1 presents the height that we measured
of four buns per portion of dough, the average
of those four and the maximum error. Figure 1
shows the results of table 1.
Conclusion
Bibliography.
The buns with more sugar were higher,
because there is more sugar to convert. And
we can see in our experiment that there is a
maximum amount of sugar that helps the
bread rise. In our experiment this is about 10
grams, but in a larger bread this would be
more. Because in a larger bread there will be
more yeast to convert the sugar and there will
be more dough to rise.
We can conclude that sometimes
there is too much sugar in bread then
necessary. This can cause people to think that
they are eating healthy, while this is not
entirely the case.
1. Chemistry network. Center of
Educational Training, Assessment and
Research. Vrije universiteit
Amsterdam. Fermentation.
2. http://www.mijnwoordenboek.nl/vert
alen.php?src=NL&des=EN&woord.
3. http://www.jannekes.nl/index.htm?url
=/brood/index.htm
4. http://www.broodrecepten.nl/recepte
n/Basisrecepten.htm
Discussion
Dough 1 had less foam after 45 minutes,
because there wasn’t any sugar so
fermentation wasn’t possible (picture 1). After
we added the oil we saw that the
fermentation process started. We think that
yeast can also convert oil. Oil seems to be able
to replace sugar in this fermentation process.
This could be an option for another
experiment.
With a higher amount of sugar the
bread gets darker. Sugar is a carbohydrate and
there are proteins in flour. During the baking
these two react. This reaction is called the
Maillard-reaction. The end product is that the
bread turns brown. This is why the bread with
a higher amount of sugar is darker. (picture
3&4)
We don’t know when the Maillardreaction gets the upper hand and if
caramelizing takes place. We were wondering
if these two things happened in our inquiry
which might explain the sudden change in our
graphic. This could be researched in another
experiment.
Picture 1. Doughs 1 and 3. after 45
minutes.
Picture 4. Buns 6 and
1.
Picture 2. Dough 2 before and after 2 hours of
rising.
Picture 5. Bun 2 cut
through.
Picture 3. All the
buns.
Picture 6. The doughs 1, 2 and 3 before and after the last hour of rising