256 Chapter 10
The plasticized curd is then molded into
desired shapes and passed through a salt
brine. The mild shearing action of the twin
screws coupled with the high temperature
provides the stretching action to the curd,
consequently producing the desired texture.Post Hoop Curd Handling
Non - uniform cooling affects the fi nal cheese
quality, especially in cheeses that are pack-
aged in barrels and large blocks. The majority
of cheese (mainly cheddar) is now packaged
in 500 - lb barrels and/or 640 - lb blocks instead
of the traditional 40 - lb blocks due to the ease
involved in the post - hoop handling of cheese
and therefore enhanced production effi cien-
cies. These barrels and 640 - lb blocks cool
slower and are therefore associated with non -
uniform cooling (Reinbold and Ernstrom,
1988 ; Barbano, 2001 ). Non - uniform cooling
causes variations in the moisture, salt, and
pH within the cheese block (Reinbold and
Ernstrom 1988 ; Reinbold et al., 1992 ;
Barbano, 2001 ; Carunchia Whetstine et al.,
2007 ).
When these large blocks are cooled from
the hooping temperature of approximately
32 ° C to 35 ° C (90 ° F to 95 ° F) to the ripening
temperature below 5 ° C (41 ° F), the center of
the block cools slower than the surface,
leading to higher moisture content on the
surface of the block than in the center. The
water - holding capacity of caseins depends on
temperature. Caseins interact with and hold
the water better at lower temperatures.
Therefore, during the cooling of large blocks,
the water migrates from the center of the
block (which is warmer) to the surface of the
block (which is colder) (Reinbold and
Ernstrom, 1988 ; Barbano, 2001 ). In various
controlled studies, moisture differentials
ranging from 1% to 5.7% have been reported
between the surface and the center of a 640 -
lb block (Reinbold and Ernstrom, 1988 ;
Reinbold et al., 1992 ; Barbano, 2001 ;
Carunchia Whetstine et al., 2007 ).unique body), various specialized pieces of
equipment have been designed and are now
used in the industry.
Cheddaring, Draining, and Salting
The two basic principles of cheddaring
involve stretching and matting of the curd.
Once again, mechanized equipment has been
designed to complete these steps. One method
is endless fl exible conveyer belts in which
curd (after whey drainage) travels on moving
conveyers and is consequently stretched and
matted by the conveyers running at different
speeds.
The most common method of cheddaring
uses Cheddaring Towers (Cheddar Master ® ,
APV, Getzville, NY). Cheddar Towers
employ a vertical column approximately
11 m in height that has a cylindrical region at
the top end (1.37 m diameter and 5 m long)
followed by a region with a rectangular cross
section that tapers toward the bottom. The
cheese curds are fed into the top of the tower,
where they are compacted, leading to addi-
tional drainage of the whey. Curd compaction
is achieved by the combination of vacuum
and/or pressure. The cheddared cheese
obtained from the towers is then milled and
salted. The salted curds are fed into block -
forming towers, which have effectively elim-
inated the hooping and pressing steps in
cheese manufacture. These towers are
approximately 6 m high and approximately
28 × 35.5 cm in cross section. The salted
curd is further vacuum pressed (and addi-
tional whey is drained). The blocks are then
cut from the towers and vacuum packaged
appropriately.
In addition to the above technologies, the
manufacture of pasta fi lata type cheeses such
as mozzarella and provolone involves mech-
anized equipment in which the cheese curds
are transferred to a cooker - stretcher equipped
with a twin screw that plasticizes the product
at high temperatures (typically achieved with
hot water at 82 ° C [179.6 ° F] to 85 ° C [185 ° F]).