Biomedical Engineering Reference
In-Depth Information
Table 3.4
Physical characteristics of flour, dough and bread according to the bread-making
process
Speci fi c
volume
(mL g
−1
)
Porosity
(%)
Flour
1.5
-
Dough
0.85
-
Proofed dough
0.9-1.0
-
Wheat bread
- Straight
and dough
2.5 ÷ 3.0
20 ÷ 25
- Sponge
and dough
3.0 ÷ 10.0
a
25 ÷ 75
a
- Sourdough
3.2 ÷ 3.7
35 ÷ 40
a
According to the parameters of the technological process
Mixing during traditional processes is carried out at least in two different times
with different speeds. In the first stage (the French
frasage
), the low speed lasts
about 5 min. Water is distributed among ingredients to allow the hydration of the
protein macromolecules and the development of gluten. Air bubbles are entrapped
into the mass and their sizes vary between 30 and 100 m m [
48
] . This phenomenon
is completed during the high-speed stage (the French
malaxage
and
souf fl age
). At
the microscopic level, the sequence of events is associated with significant rheologi-
cal changes and the mass is rather wet and sticky until hydration is completed dur-
ing the cleanup stage (Fig.
3.4
). Development of the dough is completed when the
mass clears away from the walls and blades of the mixer bowl and starts to crackle
in the bowl. Furthermore, stretching deforms the dough without breaking until it
becomes a semi-transparent film [
47
], thanks to the viscoelastic properties of the gluten.
