Temperature increase
of dough is an old problem and much
has been done to resolve it. A short
analysis of the main disadvantages
arising from these dough temperature
increases may explain how gas injection
for dough cooling as recommended
by Sancassiano can be useful under
certain circumstances.
Quick Fermentation
When mixing action causes dough
temperature to rise above 24-25°C,
fermentation begins with a subsequent
loss of sugar content. As a direct
consequence, during deliberate fermentation,
the sugar content available for the
action of yeast is too low. The final
product will be unacceptable in terms
of softness and volume.
Poor Sheeting
If the dough temperature is too
high (22-24°C when using butter;
24-26°C when using margarine),
fat will start to melt with two problems
resulting:-
Lack
of uniformity in the impermeable
function of fat with improper softness
and volume.
Dough leakage, soiling
of lamination cylinders and an increase
in downtime.
Poor General Machinability
After mixing is completed, the
dough may be machined in several
ways; rolling, cutting, pressing
and sheeting etc. High dough temperatures
cause the dough to stick to lamination
cylinders and poor cutting as warm
sheet dough shrinks after cutting.
Other Problems
Further problems may arise for
from high temperatures in processing
plants. For example:
Certain products which contain
solids with a tendency to melt (such
as chocolate) must be controlled
with a low dough temperature.
In the case of biscuits, where
thickness after baking needs to be
constant, there may be problems in
the packing line.
In the past, CO2 cooling methods
generally relied on dropping CO2
(artificial snow) onto the dough
surface. Disadvantages to this are
that the surface is excessively cooled
and therefore dehydrated, but the
cooling does not penetrate to the
interior of the dough. Large quantities
of CO2 are required, increasing processing
costs.
The system developed by Sancassiano
is designed to distribute CO2 evenly
through the mixing tool controlling
the thermal range much more accurately.
The Method
Based on the injection of CO2,
a flow of the gas in liquid form,
reaches the bowl scraper. The liquid
CO2 runs through the scraper where
a hole has been specially drilled.
When the gas reaches the foot of
the scraper, carbonic snow is formed
and then forced into the dough. A
timer and electrovalve control the
quantity of CO2 delivered. The bowl
cover is sealed on with extruded,
synthetic antifriction material and
gas is transferred from the bowl
to the discharge system by means
of a centrifugal aspirator. |
