Handbook of Meat Processing

226 Chapter 11

Air Circulation

Canals for both blowing air and sucking it

are built into drying rooms. In one - level

rooms, the blowers are along the sides at the

bottom and blow the air horizontally to the

middle of the room; or the blowers are high

on the walls and blow vertically down along

the walls (Fig. 11.8 ). Rooms with more levels

have horizontal blowers placed at the bottom

of all levels, while sucking the air back takes

place higher, mostly in the middle of the

room.

Control of Air Conditions

The only regulating factor in the drying of

meat products is, in fact, the air. The amount

of water vapor, the temperature, and the rate

of circulation must be controlled. The tem-

perature is the most effective regulator; tra-

ditional meat products, especially at the

beginning of drying, need low temperature

(about 10 ° C) to prevent microbial activity.

The product dries more slowly because

control is more diffi cult at this temperature;

however, the danger of case hardening and

other mechanical faults is also lower. The

range of the relative humidity expands from

70% to 95%, according to the product ’ s

drying program.

When working with the starter culture for

manufactured meat products, initial (incuba-

tion) temperature is in general 20 – 24 ° C. (See

Chapter 21 on mold ripened sausages.)

The regulation of air parameters is per-

formed in the device connected to the drying

room. The air sucked from the room is mixed

with outside air from time to time. The super-

fl uous humidity is eliminated by condensa-

tion or by absorption. With condensation, the

temperature of the air is lowered below the

dewpoint temperature, and the water partially

condenses. The dry air is warmed and even-

tually moistened. To absorb water, two

methods are used. One of the methods is by

defects occur too often without this compo-
nent. However, fat softens the product, so
more drying is necessary for the suffi cient
hardness. The fat particles need to stick
to meat particles; otherwise, the product
becomes crumbly. Good adhesion requires a
surface of fat tissue particles without fat fi lm
and a surface of meat covered with solved
proteins, gluing the surfaces together.
Smeared fat slows down the drying rate
by covering the outer surface and by block-
ing inner channels that could otherwise serve
for moisture migration.
As a result of the enzymatic decomposi-
tion of proteins, the meat softens during the
drying - ripening (Toldr á 2006 ). The soft
texture can be controlled by mild thermal
treatment (under 50 ° C) at the end of the
drying (Morales et al. 2008 ).

Preparation

The raw material of dried products has to be
selected following stricter hygienic direc-
tives than that of cooked products because of
the initial, critical period of drying and
because of the rational decisions to be reached
for achieving the proper a w.
Meat pieces will be salted without water
(dry salting). In the preparation of the raw
mass of chopped products, the fat must be
chopped frozen, with a sharp knife, to avoid
the fat fi lm. During stuffi ng, smearing and air
holes have to be avoided. Air holes cannot be
left over in the mass (vacuum chopping,
fi lling).

Drying

Meat products are dried in ventilated rooms,
hung upon suitable (eventually mobile)
frames. The size of the room and the number
of levels depends on the capacity, the timing
of production, and the choice of products.
The frames are mostly mobile, so that they
can be cleaned and loaded more easily.