Biomedical Engineering Reference
In-Depth Information
4.3.4
Sponge Dough
The sponge dough is aimed at acclimatizing baker's yeast (
S. cerevisiae
) and
improving swelling of the flour components, loaf volume, taste and flavour of the
bread and its shelf life. It is an indirect process which, from a technological and
microbiological point of view, could be considered as an intermediate procedure
between straight-dough (or a direct process in which just baker's yeast is used to
start the fermentation) and sourdough (an indirect process in which fermentation
starts without the addition of baker's yeast). Sponge dough is obtained in two steps:
in the first dough (pre-dough) the baker's yeast is mixed with a part of the flour and
water of the recipe, while the second dough is obtained by adding the rest of the
flour, water and possibly other ingredients to the fully fermented pre-dough.
Depending on the type of bread, the length of pre-dough fermentation can vary from
3 to 20 h and as a consequence, various percentages of flour and yeast, besides dif-
ferent combinations of DY and temperature can be applied in this step (
16,
17
) . As
in the case of longer fermentations lactic acid bacteria present as contaminants from
either baker's yeast or flour grow in the dough reaching typically more than 10
8
cfu/g
and contribute to the overall quality of baked goods (
4
), the sponge dough can be
included in the category of sourdoughs.
4.4
Examples of Sourdough Applications
Once produced, the sourdough is generally submitted to various refreshments either
to activate the microbial metabolism or to increase the dough mass (Fig.
4.1
).
Different types of sourdough (e.g. type I, II or III) are used for the manufacture
of various leavened baked products, which range from traditional Italian or French
wheat bread, white pan bread, rye bread, San Francisco bread to traditional cakes
famous throughout the world such as Panettone. Examples of those sourdough
applications are given below.
4.4.1
A Traditional Italian Sourdough Bread:
The Altamura Bread
The Altamura bread is the first European bread that received the PDO (Protected
Denomination of Origin) status. It is manufactured in the Apulia region (Italy) using
specific cultivars of durum wheat (
Triticum durum
) flour and the technology is
based on type I sourdough. The full sour is obtained by a three-stage procedure in
order to gradually increase the amount of leavened dough. At each step, water and
durum wheat flour are mixed with a previously fermented dough, which is added at
the proportion of ca. 20% based on flour weight. On the basis of the ratio between
