Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~ his invention relates to the manu~acture of a
~ood product of constant cross section with a rela-
tivel~ solid main body or core and a thinner outer
layer of less solid, relativel~ mobile materialv
One exe~plary product with which the inven-tion is
specially concerned comprises a core of turkey or
o~her meat and a relatively thin outer layer of fat
within which the meat is cookedO
Thi~; application i~ a division of application
Serial No~ 354, 832, filed June 26, 1980 .
The mass-production of a food product of the
kind set forth above presents a problem owing to
the physical dissimilarity between the core and
outer layer. ~he technique of rendering the core
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and outer layer physically homogenous hy, for example
heating, is not appropriate to the food industry.
According to the present invention, a method
of manufacturing a food product is provided by co-
extruding forwardly a core and an outer annular layer,
in their desired dimensions, into a flexible fitting
casing from respective concentric orifices and in an
extrusion head of an extrusion ma~ndrel, wherein the core
is a relatively solid meat and the outer layer is a
relatively fluid fatty material~ The casing gives the
capability of producing elongate billets~ ~he casing
materlal is stored on a body portion of the extrusion
mandrel behind the extrusion head. The cross-sectional
area of the meat core is increased, and the cross-
sectional area of the fatty outer layer is reduced in a
laterally enlarged extrusion head.
The invention also includes a method of manu-
f~cturing a food product with a relatively solid core
and a more mobile outer layer comprises co-extruding
~0 the core and outer layer into a casing dispensed from
the extrusion head. The casing has a closed end
i~mediately in front of the head before extrusion
con~ences and as the extruded food product advances
from the head, the casing is carried with it. The
casing is a sufficiently close fit on the outer layer
to preserve the coherent and even extruded form ~o
provide a product such as would be obtained by the
concentric co-extrusion of two physically similar
extrudable substances.
~ hen the desired length of product has been
extruded, the product is cut and the casing closed
around the rear end, the means effecting the closure
preferably also closes the front end of the casing
of the product behind at a position immediately in
front of the extrusion head.
I'hus the essence of the invention is the dis~
pensing of the casing from the extrusion head to
contain the mobile outer layer and this can conveniently
be contrived by extruding from an elongate mandrel
with the ~asing stock stored around the outer peri-
phery of the mandrel.
The invention also includes an apparatus for
carrying out the method, comprising an extrusion head,
an extrusion mandrel through which a relatively rigid
core material can be fed from a container and the
la~er material co-extruded thereover also being fed
from a second container, and means for forming and
securing the end of a casing over the so-formed billet
as it advances from the extrusion head, and track means
for receiving the elongate extruded and cased billet
extruded from the mandrel.
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The invention will now be described by way
of example and with reference to the accompanying
drawings wherein:
Figure 1 is a partially schematic elevation
view of an apparatus for putting the present invention
into effect,
Figure 2 is a side view partly in section of
the extrusion mandrel of the apparatus of Figure 1,
Figures 3, 4 and 5 are sections on the lines
III - III, IV -~ IV and V - V of Figure 2,
Figure 6 is an elevation of the extrusion
head of the mandrel,
Figure 7 is a view of the extrusion head
with a casing prior to closure and e~erging extruded
food product,
Figure 8 is a view similar to Figure 7
showing the meat product having advanced a short
distance wit~ the casing closed,
8~ii63
~i~ure 9 is a section of the food proàuct on
the line IX - IX of Fi~ure 8; and
~igures 10, 11 and 12 are schematic plan views
illustrating ho~- a ~ood proauct in the form of an
elongate billet lea~es the n~nàrel and is discharged
into a freezing tank~
Referring initially to Figure 1 of the draw~ngs
the appara~us illustrated comprises an ext~usion
mandrel 1 fed ~Jith turkey or other meat A f~om a first
hopper 2 b~ a vane pump in housing 3 and -~ith liquified
fat material B from a second hoppe~ 4 by a vane pump
in housing 5O ~he meat is raw and deboned and prefer-
ably mechanically massaged with salt to produce salt-
soluble proteins which enhance the bending properties
f the meat~ Pipes 6 and 7 extend from the hoppers
2 and 3 respectively to the central passage and the
surrounding annulus of mandrel 1 as will be described
with reference to Figures 2 to 5. ~ipe 6 is sup-
ported by stand 8. A cutting, closing a~d clipping
apparatus 9 is positioned over the extrusion head 10
of mandrel 1 and has a reel 11 dispensing clipping
stock 120 Thin, approximatel~ 20 microns, tubular
casing stock 13 of non-toxic transparent plastics
is threaded on to the mandrel 1.
~ tiltable track 15 supported on legs 16 receives
the elongate cased billet 14 e~ruded fro~ nandrel 1~
.. , _ . ... .
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When finally discharged billet 14 is tipped sideways
through flaps 17 into a freezing tank 18~ This tipping
and the necessary starting ~nd stopping of the ex-
trusion process 7 as will be described subse~uently
with reference to Figuxes 10 to 12, is effected b~
microswitches 19 and 20~
~ he detailed construction of the extrusion
mandrel 1 will no~J be descri.bed with reference to
Figures 2 to 5 of the dra~ingsO
~ he elongate extrusion mandrel 1 has inner
and outer concentric sections 20 and 21 of circular
cross section~ The lnner section 20 provides the
totally unobstructed passage necessary for the
passage of turkey meat A which is solid in consis-
tency ofte~ comprising large natural pieces~ An
axial i.nlet 25 at the rear end of the inner sectio~
2 allows the entry of this meat from pipe 6 (see
Figure 1). ~he mandrel outer section or casing
21 defines with the inner section 20 an annular space
22 through which the mcbile fluid fat B forming the
outer layer of ~e food product flows~ A radially
extending pipe 23 at the rear end of the mandrel 1
provides an inlet for the fat from pipe 7 (see
Figuxe 1). ~s can well be seen from the sectional
views vanes 24 connec.t the inner and outer sections
20 and 21u
The extrusion head 10 is formed b~ the laterall~
enlarged front end part of the mandrel and is seen
in section in Figure 2~ ~he space 22 is constricted
here to define an annular frontwardly facing
extrusion orifice 26. ~he main length of the space
22 through which the fat flows is relatively wide to
allow free flow of the fat which, though fluid, may
be quive viscous especially in the cool ambient
conditions usual in the food industry~ ~he front-
wardly facing extrusion orifice 27 of passage 20 is
by contrast o~ enlarged area to allow the meat some
degree of physical relaxation before it enters its
casing.,
~he operation of the apparatus will now be
described ~iith reference to ~igures 6 to 12 of the
drawings.
The extrusion head 10 o~ the m~ndrel 1 is shown
empt~ in Fi~ure 6. On activation o~ the extrusivn
pumps the extrusion product comprising the core o~
meat A and annular outer la~er of fat B advances to
the front end of the mandrel 1 into the extrusion
head 10~ This can be seen in ~igure 70 The tubular
casing 13 is pulle~ forwz~d a short distance by
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g
hand from the front end of the man~rel and the
apparatus 9 operated to draw the casin~ 13 around the
front of the emerging billet 14 and to secure the
casing with a front clip 280 This pocition is
illustrated in FiguLre 8 ~d it will be noted that
with the advance under extrusion pressure of the
meat and fat the billet end part 29 becomes r~unded.
It shoulc be noted that the dimensions of the ex~rusion
head~ i,e. the diameters of cen~ral orifice 27 and
the width of annular passage 26 are those of the
billet 14 and the ultimate food product, this be~ng
a true extruslon. The casing 13 preserves this
extruded configuration. ~igure 9 shows the cross
section of the billet and the food productO
Referring now to ~igure 10 the extruded billet
14 with the closed and rounded ~ront end part 29
leaves the extrusion head 10 and apparatus 9 and
travels along the track 15 in the direction x to-
wards the microswitches 1j and 20. When the front
end part of the billet 14 contacts and closes the
first microswitch 19 extrusion ceases and the
apparatus 9 operates to form, close and clip the
rear end of the billet 14 and the front end ol the
billet i~ediately behind. The billet then resumes
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its advance driven by mean~ on track 15 to close the
second microswitch 20 which operates to tilt the
track sideways in the direction of arrows y thereby
tipping the billet through flap 17 into freezlng
tanX 1~. The billets move transversel~ of their
length through tal~ 18 and are retrieved frozen
for cuttin5 to the àesired length and an~ packaging
re~uired.
It should be appreciated that the billet 15
as discharged from the extruder is, in principle,
a food produc~ in itself suitable for slicing a~à
cooking. The casin~ 14 remains on the product right
through storage, sale and cooking to the plate~ The
freezing operation envisaged above could thus be
'15 supplemented or replaced by a cooking, smoking or
other preparation.
It should be re-emphasised that although the
invention has been described b~ way of example with
reference to turkey meat it is applicable to an~ kind
of solid raw meat~
The transparent non-toxic casing stock ma~
be of any suitable "skin" material typicâlly of
cellulose, polyamide or polyester. One suitable poly-
ester casing material is sold under the Trade Mark
l~LOPHI~.
