Biomedical Engineering Reference
In-Depth Information
Fig. 3.7
Modern rack oven (Courtesy of Rational AG, Germany)
dough mainly by radiation. Several oven doors are installed, which change the flow
of the fumes towards the upper or bottom area of the chamber to optimize baking
based on the dough characteristics. Systems that provide a better heat yield, with an
energy saving that may reach 30% compared to those from the conventional thermal
cycle ovens, are also available.
In artisanal bakeries, the most common ovens have fixed decks with separate
chambers which are arranged vertically or consist of a cabinet equipped with a
rotating rack carrying trays or frames (Fig.
3.7
). In the former ovens, baked goods
have to be loaded and unloaded by hand using long peels or special loading devices
(Fig.
3.8
)
. This operation requires time and skill. More recent solutions make it pos-
sible to vary baking conditions for each chamber. In the rack ovens, baked goods are
placed on the pans or trays located on the rack (often during the leavening stage)
that is inserted into the oven and is rotated to give a better uniformity during
baking.
In industrial bakeries, baking is a continuous operation performed in a long hori-
zontal tunnel with different sections or zones, each one having its own burner and
where the temperature is variable. Shutters control the evacuation of the water
vapour which accumulates in the chamber towards extraction flues. Baking time is
determined by the speed of the belt that transports baked goods and by the length of
the oven. According to the heating system, ovens are heated by gas, fuel oil or elec-
tricity. Microwave ovens combined with traditional ovens are also proposed, but
their application is suitable only for specific industrial purposes.
