Technology of Baked Goods - Sourdough Biotechnology - page 60

concentration of baker's yeast (higher than 2.5-3.0%). Emulsifiers and fats with a
high fusion point are also indispensable for the oxidizing properties and to stabilize
the numerous tiny alveoli that develop from the microscopic air bubbles included
during the mixing stage. Another characteristic of this process is the reduction of the
pressure during mixing to adjust the size of the alveoli.

3.4.2 Continuous Processes

These processes were introduced in the USA during 1950. The two best-known
types are the Do-Maker process, developed in 1954, and the Amflow process, devel-
oped in 1960 by AMF Incorporated [ 46 ]. These technologies took hold in the 1970s,
and were widespread especially in the United States and Great Britain.
Contrarily to the discontinuous process working in batches, the continuous pro-
cess is characterized by a substantial reduction of time, more compact machinery
and better durability of the characteristics of the baked goods [ 47 ] . These processes
are based on the possibility of eliminating the long leavening times by using yeast
cultures or pre-ferments propagated separately without or with small quantities of
flour. The subsequent high-speed mixing, with the simultaneous addition of all the
ingredients, favours volume development even without long leavening times. As for
the Chorleywood process, the intense mechanical stress during the high-speed mix-
ing can be “supported” by the dough only if strong oxidizing improvers are added;
emulsifying lipids are also indispensable.

3.4.3 The Main Stages of the Process

3.4.3.1 Mixing

As shown in Table 3.2 , during mixing ingredients are distributed and blended within
the mass, and gluten is formed. These phenomena are described as dough develop-
ment. Many variables are involved. One of these is the quantity of water added to
the flour, which may be indicated as the “level of absorption” or “hydration”. In
some processes the level of absorption does not correspond to the optimal quantity
as determined by the farinograph but it is mainly related to the handling character-
istics of the dough. Stiff dough with hydration levels between 40 and 45% (dough
humidity: 38-41%) has reduced extensibility; consequently, the baked goods have a
limited porosity with a very fine alveolar structure. Soft or slack doughs have hydra-
tion levels higher than 60% (dough humidity: about 50%). They are difficult to
handle due to their low consistency, which is responsible for the long and irregular
shape such as the Italian Ciabatta [ 2 ]; the crumb presents large alveoli, often long in
shape, which result from the coalescence of smaller bubbles.