Biomedical Engineering Reference
In-Depth Information
sourdough procedure. The first step consists of the mixing of a part of the mother
sponge (
levain chef
) with flour and water to achieve around four times the initial
mass. This dough (DY 160) ferments for 1.5-2 h at ca. 25°C and is named
levain de
première
(fresh sour). It is used as a starter to obtain a dough with a DY of ca. 185,
which ferments for 7-8 h at a temperature slightly higher than the previous one.
Those parameters, including the long mixing time to oxygenate the dough, stimu-
late the growth of yeasts and the leavening capability of the
levain de seconde
(basic
sour). By using this dough as the starter for the third refreshment, the last dough or
levain tout point
(full sour) is obtained after a short fermentation time (ca. 2 h) with
the aim of controlling the hydrolytic activities of the dough and of preserving the
gas-retaining and bread-making capabilities. The
levain tout point
is used at the
proportion of 25% with respect to the mass of the final dough and the dough is ready
for baking after 30 min of leavening (
2
) .
4.4.3
Rye Sourdough Bread
As reported for French bread, the rye or wheat/rye flour sourdough bread is obtained
using single or multi-step protocols, depending on the type of bread making and
product. The “three-stage sourdough process, basic-sour overnight” requires ca.
15-20 h and, as described by Spicher and Pomeranz (
17
), represents a good refer-
ence model for type I sourdough application in rye-flour-based bread making. The
first stage leads to the
anfrischsauer
(fresh sour), which, in turn, is started by the
anstellgut
(mother sponge), a commercial starter or a part (ca. 10-15% of the total
dough weight) of a full sour (
vollsauer
) from a previous bread making. The
anfrischsauer
has a DY of 200-250 and ferments for ca. 6 h at 25-26°C. Afterwards,
it contains a high number of yeasts and it is used to start a new dough based on rye
flour and water (DY of about 160-180). After 5-8 h of overnight fermentation at
26-30°C, lactic acid bacteria grow and the
grundsauer
(basic sour) is obtained.
A further refreshment (3 h at 30-33°C), using the basic sour as the starter for a mix
of rye flour and water (DY 180-200), leads to the
vollsauer
(full sour), which has
values of pH and TTA of 4.0 and 10.5 ml NaOH 0.1 N/10 g of dough, respectively.
A part (40%) of this sourdough represents the natural starter for the final dough (DY
170), which contains rye flour and an equivalent amount of wheat flour in the case
of a rye/wheat flour bread preparation. The dough is baked after dough resting of
10 min at 28°C, followed by proofing.
4.4.4
White Pan Bread
The white pan bread is one of the most diffused breads in the United States and
represents a good example of bread that is manufactured using type II sourdough.
As reported by Kulp (
8
), the manufacture of this bread relies on a “one-stage system”
