What is bakers yeast [621170]

What is baker’s yeast?
Baker's yeast:
is of the species Saccharomyces cerevisiae
is a single -cell microorganism found on and around the human body
it converts the fermentable sugar present in the dough intocarbon
dioxide andethanol

Types of yeast used in panification
LIQUID YEAST
COMPRESSED YEAST -is the most used
DRY YEAST

History
The first yeast definite records come from Ancient Egypt.
Researchers speculate that a mixture of flour meal and water was left
longer than usual on a warm day and the yeasts that occur in natural
contaminants of the flour caused it to ferment before baking. In the
19th century, bread bakers obtained their yeast from beer brewers.
The slurry yeast made by small bakers and grocery shops became
cream yeast, a suspension of live yeast cells in growth medium, and
then compressed yeast, the fresh cake yeast that became the
standard leaven for bread bakers in much of the Westernized world
during the early 20th century.

Experimental part
Research purposes : Thedensity dough changes by the power of
yeast growth is depending on expiration date.

Materials and methods
It was used compressed yeast produced by ROMPAK.
Determination of power growth through method Ostrovschi
The technological determination of potential through baking sample

The determination of power growth
through method Ostrovschi
The principle of the method consists in the determination of growth by
placing a ball of dough in an amount of water which has a temperature
of 32 °C and the time is measured in which the ball of dough rises to the
water surface.

The time
Yeast Fresh Outdated
Increasing
power (min)9 13
Fresh yeast Outdated yeast

The technological determination of
potential through baking sample
Bread recipe:
-500 g flour
-15 g yeast
-10 g salt
-260 g water

Conclusions
After the determinations, it was found that as time goes and
closeness to expire, the power of yeast decreases.

References
1.Banu C. și colab. –Manualul inginerului de industrie
alimentară ,vol.II , Editura Tehnică București, p.1097,1999.
2.Bordei Despina -Tehnologia modernă a panificației , Editura
Agir, București, p.160 -161, 2004.
3.Carlson T.G. –Law and Order in the Wheat Flour Dough –
Colloidal aspects of the wheat flour dough and its lipid and
protein constituents in aqueus media. Dissertation, University
of Lund, p.85, 1981.
4.Dan Valentina –Microbiologia alimentelor , Editura Alma,
Galați, p.150 -162, 2001.
5.Giurea A.M. -Referat nr. 1 –doctorat -Universitatea „Lucian
Blaga” -Sibiu, p. 5, 1996.

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