WA °“@ XNV

=
a
os
<a

 

AMY B, VAUGHN

i me 7
i d dy

 

ieee ces eee ee a ti as as STS a

 
THESIS
 

 

 

__—e

—-~

—~ec,
-- T-~-H-E-S-I- S:-
on

~B-R-E-A-D-

.
Amy B. Vaughn.

quests gy,

Summer 1897.

Michigan Agricultural College.
(1)

BREAD
22-0...

Bread is the most important food that has be:.n adopted
by mankind. Nothine in the range of domestic life so affects
the health of people as does their daily bread. Good vréad
is the product of hign art, a proof of advanced civilization.
A weil-baked aeratcd loaf of bread is the pride of the house-
wife, while heavy sour bread is a cause of humiliation. But
it is an actual fact that rood wholesome bread is the excenr-
tion in many homes. Why should it be? Bread-making is one
of the easiest branches of culinary science, if only a little
thournt and attention be given to it.

It wou.d be presumptuous for me to attempt to give a
scientific treatise on the pasis Of mv own experiments; for
the science of bread-making has not yet been satisfactorily
worked out. I shall merely state what knowledge I have gained
from this interesting study and the experiments which I have
performed in regard to it.

For the making of good bread we require only yeast, flour
and some liquid. Saccharomycetes or yeast fungi are one
celled plants of the lowest form of vegetablc life. They
multiply by budding. They liWe isolated or in colonies. The

cells are rlobular, oval, or elliptical in shape. For the

0)

1O20L17
(2)

Purpose of multiplying the cell pushes out a small rounded
protuberance which becomes filled with some of the contents
and gradually assumes the form and shape of the mother cell.
The best condition for the ecrowth of the yeast plant is a warm
moist sweet nitrogenous soil. The yeast plant is kilied at
a tomperature Of 212 F, while freezing does not destroy it,
if it is slowly thawed so that the cells are not broken. I
used Fleischmann's Veast for all my experiments. It is very
essential that this yeast be fresh.

The next important ingredient for bread making is the
fiour. It is not essential to have extremely white flour
but ve must have flour which contains considerablo gluten.
Gluten is a nitrogenous flesh-forming element of a dark grey-
ish color. If of good quality it will be very elastic and not
sticky wnen separated from the flour. To obtain the gluten
from the flour I took two parts of flour to one Part of water
and formed a stiff dough. I then allowed water to run over
the dough, vashing out the starch and lcaving only the gluten.
We obtained the same material when we chew rheat. The more
rluten flour conkains, the better it will be. Good flour
should leave an impression of the fingers when squeezed in the

hand. It should be elastic, easily handled, a littie gritty
(3)

in texture, and vhen made into dough should take up consider-—
able vater.

As to the liquid in bread-making one can use either water
or milk or a mixture of the two. Bread which is made vith
milk dries outmore quickly than when made with water. I find
no difference in taste.

Salt is also added to the bread to season it. A little
surar and butter too may be added, but merely as a matter of
taste.

In making bread for one loaf I used:

1/4 caxe yeast,dissolved in warm water.

1/2 cup of warm water.

1/2 tsp. Salt.

1 " sugar.

1/2 " Butter.

21/4 to 2 1/2 cups Flour.
These I mixed in the order given. Then I very thoroughly
Kneaded this dough, and kept it at an even tempertature by
Placing it in warm water untii it had doubled its bulk. I
then kneaded it thorouchly again, kept it at an even temper-
ature, and when it had again reached double its bulk, placed

it in a hot oven.
 

 
Now so back to what takes place in the dough when first
mixed. The flour contains some glucose, this glucose is
broken un by the action of the yeast. It is not Known in just
what way this takes place, but as a result, instead of glucose
we have carpondioxide gas and alcohol.

Cc Ha Oc + Yeast = 204 He O + 200% One part of glucose
= 8 parts of alcohol + 8 parts of Carbondioxide gas. The
fluten in the douch, being elastic, expands and nolds the
C O71 gas, thus causing to be formed little gas bubbles through
out the douch.

Kneading of bread is the process of thoroughly working
the douph, the first time for the purpose Of thoroughly mix-
ing the ingredients and the second time to make the gas
bubbles of equal size. The bread should be taken from the
bowl, and placed on a slightly floured molding board. Then
with the tips of the fingers pring the parts of the dough
which are the farthest away up tovard the center, next push
the dough back with the base of the hand. Continue to do this
until the dough when pressed with the finger will spring
quickly back in place. One must be careful as to the amount
of flour used while kneading the oread. Themis danger of
retting too much and thus making the bread tough. In the

first kneading use only what is essential for the handling of
(5)

the dough. In the second kneading, if possible, no flour
should be used.

The temperature at which bread should be raised is a wery
important consideration. Host people who have studied this
subject give no exact temperature, but agree that it should be
between a temperature of 70°F and 80 F. I have experimented
with the following temperatures:

time to raise

1g0°F . .. . .55 min.

90°F . . .lhr.43 "

85 *.. .thr.10 *

80°F . . .lhr.g0 "

777. . .lhr.45 *

75 F.. .lhr.50 *

GBF... .@hr.40 "

50°F . . .4nr.35 "

40°F .°-. .9hr.20 *
I found that bread kept at a temperature of 120 F was entirely
too lignt and had no sweet nutty flavor. This same fault is
found with pread kept at a temperature of 90°F or 85 F, while
there appeared very little difference in the bread Kept at

75 F or 8b F. The pread kept at CBF or 50° F was rather neavy.
 

 
(6S)

At the temperature of 40 F. the acetic fermentation haa set in
rendering the pread unfit for use. From my experiments I have
obtained the pest results from a temrerature of 77 ~*F.

In baking the oven should be at a temperature Of about
360° F or hot cnouzh to brown to a rich color a teaspoonful of
flour in five mimuites.

In baking when the crust is formed the starch has been
changed into dextrin which pives the brown color to the crust
and the darker prown which is often obtained is carmel or

i TTT
melted surar. And as alleugad moet be changed into. starch

“. ate —- _ +

before veiling digested this is why the crust is more easily
digestcd. The temperature on the outside of the loaf is 400°
F and in the inside only 21¢ F as the water can only reach
that temperature.
When the oread is thoroughly baked it comes easily from
the pan and the pottom of the loaf will not burn the hana.
When taken from the oven the bread should be placed on
a bread rack so as to allow the free circulation of air around
it, but cover the top so that that no hard crust wiii be
formed. When cold the bread should be placed in an air tight

tin box so as to prevent its drying out.
(7)

The pread has been oaked for the purpose of cookingthe
starch driving off the alcohol and the C O gas. ‘When the bread
becomes dry if placed in the oven for sometime it will regain
its freshness and taste almost like a fresh loaf.

The aim in bread-making is to secure a loaf which is
sveet and nutty in flavor, is of uniform, fine texture and

has a light brown crust. But the essential point is that it

be wholesome.
 

ge
ere,
s

 

 

 
 

rw 74
bo

 

 
TH