Note: Descriptions are shown in the official language in which they were submitted.
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_ WO 95/16367 P~CT/US94/14D27
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The present invention relates to a process for preparing
a retort-stable, shaped food piece which is cohesive and
maintains its shape when retorted. . The present invention
further -relates to the retort-stable, shaped food piece
IS prepared by the process of the present invention.
LACK ~ O 'InTn O Tnmr~~mTnTT
Pet owners typically have a great deal of affection for
their pets. Many, in fact, consider their pets to be members
of theirfamilies, and treat them accordingly by indulging
20 them to a great degree. One of the ways owners indulge their
pets is by the food they purchase for' them. In this context,
many owners derive pleasure from feeding their pets foods
which contain shaped food pieces which the owner identifies
with the particular type of pet. An example of this would be
25 a bone-shaped food piece in a dog food.
Of course, these shaped food pieces must also contribute
to satisfying the nutritional requirements for the particular
pet. To. accomplish this, the shaped pieces are preferably
prepared from proteinaceous and farinaceous material. The
30 term proteinaceous material refers to glutens such as wheat
' gluten. Pro~einaceous material obtained from other sources
such as defatted oil seed protein material; and other known
proteinaceous sources (e.g., meat, fish, etc.) are not of use
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in the present invention. The term farinaceous material
refers to cereal-flours such as wheat flour.
One problem in preparing- such shaped pieces is--that many '
pet foods have to undergo the extreme processing conditions of
a retort sterilization procedure. For - certain shaped
proteinaceous materials, such as-meat analogs, this is not a
concern. These meat analogs retain their analog properties
even when subjected t.oa retort operation. However, these
meat analogs are structurally different than the shaped pieces
of the present invention in that they are typically prepared
from texturized vegetable- protein (TVP) and may have a -
striated texture. By 'striated texture~~ it is meant that the
shaped piece tends- to have a texture analogous to muscle
striations. This striated texture allows the shaped piece to
be easily torn apart along the striations, and as -such the
piece does not haveto maintain a distinct and definite shape
when subjected to a;retort operation.
The shaped pieces of the present invention do= not have
such a striated -texture, however, but instead are; for the
most part, cohesive. Until now; shaped pieces having a
cohesive texture like those of the present invention could not
withstand the extreme conditions of a retort operation, but
would typically dissolve when retorted. This would be
undesirable since the -shapedpiece would not maintain its ,
original shape and form, but would be unrecognizable.
Thus, shaped food pieces: having the cohesive consistency
of the shaped pieces of the present ixivention-are useful only
when they are -retort-stable, i.e., do not dissolve - upon
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hydrationand/or retorting, but maintain their desired shape.
The present invention provides such a piece, as well as a
' process for its preparation.
There are numerous processes known in the- art for
producing shaped, extruded, edible proteinaceous products.
U.S. Patent 3,968,268, issued July 6, 1976 to Sair et
al., discloses a process for producing hydratable, translucent
to glassy, proteinaceous products, and the resulting products
themselves. In the claimed process a water-moistened, edible
proteinaceous material having at least about 40% by weight
protein, on a dry weight basis, and an effective amount of
water, within the range of about IO to SOa, is subjected to
working under effective mechanical pressure with added heat
IS sufficient to convert it to a hot, moist, plastic extrudable
mass. This hot, plastic mass is extruded through and from a
length of a temperature controlled, elongated die under non-
puffing conditions. The extruded product is unpuffed,
substantially homogeneous, translucent to glassy, and
characterized by having texture and retaining its structural
integrity under retorting conditions. This product is alleged
to be pleasing in the mouth and have protein cell bodies with
the pleasing feel, firmness, structure, texture, coarseness,
. or bite characteristics found in, uncooked or cooked food
products.
Sair et al. also- teach that in their process the
proteinaceous material must be heated to a sufficiently high
temperature to retain retort stability. Specifically, they
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teach that extruded proteinaceous materials which are extruded
at temperatures of .180°F., 210°F., and 230°F.,
completely
disintegrate when subjected to retorting. This is contrary to '
what has been found in the present invention, where the
products are shaped and formed at low dough .temperatures and
maintain their shape when retorted.
U.S. Patent 3,965,268, issued June 22, 1976 to Stocker et.
al., refers to an expanded protein product comprising a
sulfur--containing organic compound. Stocker-.et al. claim a
method of preparingr an expanded edible protein product having
an open, cellular structure, the method comprising forming an
admixture of proteinaceous material having a protein content
of at least about 30% by weight, from about 0.05% to about
2.0% by weight of..aaid proteinaceous material of a sulfur-
containing organic compound selected from the group-consisting
of cysteine-- hydrochloride, D,L-methionine, -- sodium
lignosulfonate, thiamine mono~itrate, calcium thioglycollate,
and mixtures thereof, and water in an amount sufficient to
result in a moisture content of 15% to about 50% by weight of
said admixture; heating the mix to a temperature above about
220°F; mechanically working the heated mix at a pressure
substantially above atmospheric pressure; and expanding the
mix by suddenly releasing thepressure. The expanded product
has a crisp, crunchy texture -which lends itself to use in a
large number of foodstuffs, for example snack items.
As can be seen, the product of the process taught by
Stocker et al. has a different texture than the shap-ed edible
piece ofthe present invention. Furthermore, the prooess
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taught by Stocker-et a1. includes a heating step which is not
required in the process of the present invention.
As already stated herein, it is also known to make a
striated, texturized shaped meat analog. This technology uses
a vegetable protein, or extract, along with a sulfur
containing compound, typically a sulfur-containing amino acid
or pure sulfur itself, to make the striated, texturized piece.
An extrusion process operated under high shear a.nd temperature
conditions is typically used to manufacture this meat analog.
The -high shear and temperature conditions facilitate the
cross-linking of the vegetable proteins.
The resulting extruded meat analog is typically very
porous, and upon hydration expands to several times its dry
weight and size. . The-hydrated meat analog is also porous and
is spongy to the touch and chew. After retorting, the
hydrated and retorted meat analog is spongy and soft. The
meat analog is easily torn apart following retorting, due to
its striated structure.
As can be seen, there is-nothing in the, art which teaches
the -shaped piece grepared by the process of the present
invention. It is. therefore an object of the present invention
to provide a process for preparing such a shaped food piece
which is cohesive anal maintains a definite and distinct shape
~ and integrity when hydrated and/or retorted.
It is another object of .the present invention to provide
an edible, shapezi food--piece which is cohesive and maintains a
definite and distinct shape and integrity when hydrated and/or
retorted.
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These objects are accomplished by the invention described
herein. ::_. . ...
Unless otheruiise specified, the weight percentages
provided herein for the components of the premixture are on a
wet basis.
S 1MMARV Q TH TMTS1F7T't'T~7N -
The present invention relates to a process forpreparing
a cohesive, retort=stable, shaped food piece, safe process
comprising:
(a) preparing a premixture comprising
(1) from about 20% to about 80% by weight gluten,
(2) from about 20% to about 80% by weight flour,
(3) from -0% to about 50% by weight meat and bone
meal,
(4) from b% to about 9% by weight fat,
(5) from D% to about 0.7% by weight added sulfur,
(6) from - 0% to about 2% by weight - dicalcium
phosphate, wherein the weight percentage of the
premixture- -components are expressed as a
percentage of the premixture;
(b) combining the premixture with water to_form a
secondary mixture, wherein the ratio of premixture
to water is in the. range of from about _1.6:1 to
about 4:1;. ,
(c) mixing the- secondary mixture for a period- of time
sufficient to obtain a substantially uniformly mixed
dough and under--conditions such that the temperature
of the secpndary mixture and uniformly mixed dough
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in the mixing operation are maintained in the range
of from about 15°C to-about 45°C; and
(d) forming the uniformly mixed dough into a desired
shaped piece, wherein the forming operation is
carried out in -conjunction with low specific
mechanical energy and high pressure conditions, and
under conditions such that the temperature of the
uniformly mixed dough in the forming operation is in
the range of- from about 40°C to -about 100°C, and
wherein said shaped piece is cohesive and maintains
its shape when retorted.
The present invention further relates to a piece prepared
by the above-described process.
~~TATT FD nE~CRTPTTON OF THE IN~1FN't'TON
The present invention comprises a process for preparing a
retort-stable, shaped food piece. The piece maintains its
shape when hydrated and retorted, e.g., if the piece is
originally formed in a-bone shape, the hydrated piece will
maintain the bone shape and the retorted piece will maintain
the bone shape.
In the process-of the present invention a premixture is
initially prepared. The premixture comprises from about 20%
to about 80%, preferably from 20% to about 40%, more
preferably from-about 25% to about 35% by weight gluten; from
0% to about 50%, -preferably from about 1% to about 30%, more
preferably from-2% to about 15% by weight meat and bone meal;
from -about 2.0% to about 80%, preferably from about 30% to
about 75%, more- preferably from about 35% to about 65% by
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weight flour; from 0% to about 9%, preferably from about 1% to
about 8%, more preferably from about 3% to about 6% by weight
fat; from D% to about 0.7%, preferably from about 0.01% to
about0.5%, more-preferably from about 0.1% to about 0.2% by
weight added sulfur; and from 0% to about 2%, preferably from
about 0.1% to about 1% by weight dicalcium phosphate.
The gluten of the present invention is preferably wheat
gluten. It is believed that other glutens, such as corn
gluten, may work -in the present invention as well. These
IO other glutens may also be combined with wheat gluten in the
premixture.
Wheat gluten is a concentrated natural protein in the
form ofa light tan powder having a bland taste and aroma.
Wheat gluten is known to consist mainly of gliadin (prolamine)
and glutenin (glutelin), which are the principle cereal
proteins; together with other components of the endosperm
cell. Wheat gluten;is separated from wheat flour by a washing -
method known to those skilled in the art.
The precise amount of gluten contained in the premixture
of the present invention, while within the range of from about
20% to about 80 % by weight, is dependent upon the particular
type of gluten being utilized. The preferred wheat gluten
comprises from about 2D% to about 80%, preferably from about.
20% to about 40%, more preferably from about 25% to -about 35%.
by weight of -the premixture. -:The gluten may be provided to
the premixture in the form of isolated gluten added to the
premixture, gluten :inherent in the .flour present in the
premixture, and mixtures thereof.
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The flour used in the present invention can be any type
of flour obta'i.ned from known grains. Examples of flours
. useful in the present invention include, but are not limited
to, wheat flour, corn flour, oat flour, and mixtures- thereof,
with wheat flour being preferred.
As with the gluten, the precise amount of flour used in
preparing the premixture of the present invention, while
within the range of from about 20% to about 80% by weight, is
dependent upon the particular type of flour being utilized.
For example, when wheat flour is used the premixture comprises
from about 20% to about 80%, preferably from about 30% to
about 70%, more preferably from about 50% to about 65% by
weight wheat flour; when corn flour is used the premixture
comprises from about 35% to about 7D%, preferably from about
35% to about 60%, more preferably from about 35% to about 50%
by weight corn flour.
Other types of cereal flours known to those skilled in
the art can be used in the present invention. The precise
amounts of these cereal flours-useful herein will fall within
the range of from about 20% to about BD% by weight, and can be
determined by one skilled in the art.
The fat which may be added to the premixture of the
present inventian may be obtained from any fat source known to
those skilled in the art. Examples of fat sources useful in
the present invention include, but are not limited to, choice
' white grease, beef tallow, soy oil, corn oil, vegetable oil,
and mixtures thereof, with choice white grease being the
preferred fat source.
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The amount of :a particular fat source that must be used
in the premixture is that amount necessary to provide-a total
fat content in the premixture-in the range of from D% to about -
9%, preferably from about 1% to about 8%, more preferably from
about 3% to about.6% by weight. Of course, the required-
amount of a particular fat source necessary to achieve this
will vary- for differing fat sources. However,- this is
something one skilled in the art can determine. When the
preferred choice white grease is used as the fat source, the
premixture -comprises from 0% to about 9%, preferably from
about 1 % - to about 8% , more preferably from about 3 % to about
6% by weight choice white grease.
When fat is included- in the premixture--of the present -
invention it facilities the process of the present invention
IS by lubricating --the material flow through the forming
operation, thereby lowering shear and energy transfer to-the
product.
The sulfur which may be -added to the premixture of the
present invention may be in the form of pure sulfur-flr either
as an organic or inorganic sulfur-containing compound.
This sulfur is considered "added sulfur~~ and is added to
the premixture separately from- the- other pz'emixture
ingredients and in a manner- sufficient to contribute the =..
specified amount of sulfur to the premixture. -Sulfur- may also
be present in the other premixture ingredients (e. g., gluten,
flour, etc.), but any such amounts are typically not '
significant and are not considered when determining the amount
of sulfur added to tile premixture. -
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WO 95116367 ~," ~;l c. '..: ~ , ~ .
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Any type of_ sulfur-containing compound useful in the
preparation of edible foodstuffs may be used in preparing the
premixture of the present invention. Examples of useful
sulfur-containing organic compounds include, but are not
limited to, sulfur-containing amino acids, lower alkyl
mercaptans, lower alkyl sulfides, lower alkyl disulfides,
thioacids, and other compounds, for example thiamine, may be
employed. Among these, compounds such as cysteine, cystine,
methionine, thiodipropionic - acid, thioglycollin, thiamine,
lignosulfonic acid, -and their salts are preferred, with
methionine being most preferred.
The amount-of a particular sulfur source that must be
used in the premixture is that amount sufficient to provide a
total added sulfur content in the premixture in the range of
from 0% to about 0.7%, preferably from about 0.01% to about
0.5%, more preferably from about O.i% to about 0.2% by weight
of the premixture. Of_ course, the required amount of a
particular sulfur source necessary to achieve this will vary
for differing sulfur sources, although falling within the
broad range specified above, and will be apprECiated by one
skilled in the art. When the preferred methionine is used as
the sulfur source, it comprises from 0% to about 2%,
preferably from about O.I% to about -1%, more preferably from
0.2% to 0.5% by weight of the premixture_
The dicalcium phosphate, when added to.the premixture of
' the present invention, comprises from 0% to about 2'%,
preferably from -about 0~1% to about to by weight of the
premixture.
WO 95/16367 ~ ~ ~ ~ ~ PCTIU594114027
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The meat and bone meal, when added to the premixture of
the present invention, is a' source of protein and flavor.
When used, the meat. and bone comprises from 0 % to about 50%,
preferably from about 1% to about 30%, more. preferably from
about 2% to about 15% by weight of the premixture. There is
no known preferred Source of meat and bone meal, and as such
the meat and bone meal can be obtained from any commercial
source known to one skilled in-the art.
Other optional ingredients which may be added to the
premixture of the -present invention include, but are not
limited to, edible fiber sources,--nutritional supplements, soy
grits, coloring agents, and flavoring agents.
When such optional ingredients are added ' to the
premixture, the leuels at which they are added will vary
depending upon the particular optional ingredient. - When soy
grits are- included in the premixture they typically comprise
from 0% to -about 30%, preferably from 1% to about 15%, more
preferably from about 2% ta= about 7% by weight- of the
premixture.
When adding the meat and bone meal, fat, sulfur,
dicalcium phosphate, and other optional ingredients, care must
be taken to avoid adding amounts of such ingredients which may
disrupt the formation of a gluten matrix. If such disruption
occurs, then retort stability may be adversely affected.
Coloring agents: and-flavoring agents are added- to the
premixture at levels- necessary to impart the desired flavor
and color to the fiiialproduct, which will be dependent upon
the preferences of the particu7_ar formulator. Such coloring
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~R'O 95116367 P(.'TIUS94114027
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and flavoring agents are typically added to the premixture at
levels of less than le by weight.
The premixture i~ next combined- with water to form a
secondary mixture. The ratio of the premixture-to water is in
the range of about 1.6:1 to-.about 4:1, preferably from about
1.65:1 to about 2_51, more preferably from about 1.65:1 to
about 1.85:1.
Any type of--water may be used to form the secondary
mixture of the .present invention, -i.e, deionized water,
purified water, distilled water, tap water, etc. Of course,
care should be taken to ensure that the water does not contain
any impurities that may have an adverse effect on the final
shaped piece produced in the present invention, i.e.,
particulate matter- that might- interrupt the gluten structure
and adversely affect retort stability.
After the secondary mixture is prepared, it is mixed for
a period of time sufficient to obtain a substantially
uniformly mixed dough. Care must be taken to avoid mixing the
secondary mixture -past the .point of minimum mobility or the
dough (gluten structure) breaks down, and the resulting piece
will not be retort stable.. The. minimum mobility of the
secondary mixture can be determined by one skilled in the art.
The secondary mixture may be mixed by any method and/or
apparatus known to those skilled in the art. Examples of
mixing methods and/or apparatus useful in the present
invention include, but are not limited to, a paddle mixer, a
ribbon mixer, and a Hobart mixer (auger mixer), with a ribbon
mixer being preferred.
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The secondary mixtureismixed under conditions such that
its temperature and the temperature of the resulting uniformly
mixed dough are maintained in the range of from about 15°C to
about 45°C, preferably from about 20°C to about 30°C,
more
preferably from about 20°C to about 25°C.
The length of-time necessary for mixing the secondary
mixture to obtain the substantially uniformly mixed dough will
depend upon the method of.mixing used. When a ribbon mixer is
used, the secondary mixture is typically mixed for a period of
time in the range' of from about 2 to about 1D minutes,
preferably from about 3-to about 8 minutes, more preferably
from about 4 to about 6 minutes.
After the substantially uniformly mixed dough is
prepared, it is formed into the desired shaped piece. It is
important that this forming operation or tep take place in
conjunction with low specific mechanical energy and under high
pressure conditions. The lowspecific mechanical energy and
high pressuxe conditions act in combination to provide the
structural bonding necessary to have a retort-stable, final
shaped piece.
The forming operation is carried out in conjunction with
specific -mechanical energy in the range of from -about 6
watt~hr./kg:to about 70 watt~hr./kg., preferably from about 6
watt~hr./kg. to about 50 watt~hr./kg., more preferably from
about 6 watt~hr./kg. to -about 35. watt~hr./kg., and under a -
pressure of at least'about 400 psig, preferably at least about
500 psig, more preferably atleast..about 600 psig. - If the
pressure under which the forming takes place is too low, a
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WO 95!16367 PCT/US94114027
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final cohesive shaped piece will not be produced, butinstead
discreet separate individual particles will result from the
forming operation.- Furthermore, even if the pressure is
sufficient to provide- a uniform, solid, discreet, shaped
piece, it still must be high enough to allow for some
expansion of the uriiformly mixed dough after the forming
pressure is released. By this it is meant that there must be
sufficient pressure in the forming operation that when the
pressure_.is- released, the shaped dough product will have a
slight expansion due to r-elease of the pressure.alone. The
expansion is not due to any gas evolved after the pressure
release or amy other internal forces, other than the plastic
reformation of the shaped product material.
It is also important. that the forming operation take
place under conditions such that the temperature of the
uniformly mixed dough remains in the.range offrom about 40°C
to about 100°C, preferably from about 40°C to about 90°C,
more
preferably from about 45°C to about 90°C, still more
preferably from about 60°C to about 80°C. The specific
mechanical energy and pressure will contribute to the increase
in temperature ofthe substantially uniformly mixed dough as
it is being formed into the desired shaped piece. However,
care should be taken tominimize the temperature rise during
the forming of the dough in order to-minimize gelatinization
of -the dough and keep the dough temperatures within the ranges
' specified herein. -
Although gelatinization of the starch is minimized, some
gelatinization is necessary to form thedesired shaped piece.
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However, if them is too much gelatinization the formed piece
becomes highly hydrophilic and is not retort stable. The
correct degree of geiatinization will provide a product which
is neutral to hydrophobic. It is also possible that an overly
gelatinized piece will form an expanded cell structure, which
can cause the shaped piece to lack retort integrity as well.
The temperature - of the- substantially uniformly mixed
dough is also kept low to avoid -generating steam during the
forming operation. and causing the piece--to have an expanded
cell structure. If any steam is generated, then _when the
pressure-.is released during the forming operation it is
possible that the steam will expand the shaped piece; causing
the shaped piece to have an undesirable texture --and lack
retort integrity. All of these problems can be avoided by
maintaining the temperature of- the dough below its
gelatinization point:
In a preferred..;embodiment of the present invention, the
forming operation takes place-in -a low shear extruder. The
low shear extruder in- essence. is an extruder-which-operates
under low specific mechanical-energy conditions and produces a
product having a low dough temperature: Cooling of the low
shear extruder maybe necessary to control the dough
temperature if the .specific =mechanical energy causes the
temperature to--rise toa high. However, this is unlikely under
25, the low specific mechanical energy conditions under which the
forming operation is Carried out. -
In this preferred embodiment, the low shear extruder is
operated at a speed -in a range of from about 40 to:60 RPM,
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preferably from about 45 to about 60 RPM, more preferably from
about 50 -to about 60 RPM; the temperature of the dough as it
- exits- the low shear extruder is in the range of from about
40°C to about 85°C, preferably from about 45°C to about
65°C,
S more preferably from about 50°C to about 60°C; the pressure
at
the exit of the low shear extruder is at least about 400 psig,
preferably at least about 500 psig, more preferably at least
600 psig; and the dough is extruded at a rate of 100 to 300
kg. dough per hr., preferably from about 100 to about 275 kg.
dough per hr., more preferably from about 100 to about 250 kg.
dough per hr:
In the -present invention it has been found that a 4"
diameter Bonnot 5-zone extruder is a preferred low shear
extruder. While the reason for this preference is not exactly
known, it is believed that the Bonnot extruder has a
particularly desirable screw profile for use in the process of
the present invention. This extruder is available from The
Bonnot Company, located in Uniontown, Ohio.
Another-way of forming the uniformly mixed dough into the
desired shaped piece is to charge the uniformly mixed dough
into -a cylinder having a die head and a punch mechanism. When
the cylinder is used, the punch mechanism is pressed into the
dough-containing cylinder to cause the dough to be extruded
through the die head, thereby forming the dough into an
extruded rope having the desired cross-sectional shape. This
extruded rope is then cut cross-sectionally along its length
to obtain a discrete piece having thedesired shape.
While not intending to be bound by theory, it is
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surprising and unexpected chat the gluten and flour, and
especially wheat gluten and wheat flour, when processed under
the low specific mechanical energy, low dough temperature, and
high pressure conditions of the process of the present
invention produces a cohesive-shaped piece which maintains its
distinctive definitive shape upon hydration and retort. This
is especially unexpected when it is considered that the
product of the present invention is prepared using a low
specific -mechanical energy, low temperature, high pressure -
forming process. As already stated herein, the prior art
teaches that high temperature extrusion (i.e., forming) is
necessary to obtaina retort-stable piece. The art teaches
that temperatures of at least about 250°F are necessary for
preparing a retort-stable product, and that retorted,
proteinaceous extruded products which are extruded at
temperatures of 180°F, 210°F; and 230°F dissolve when
retorted.
A preferred process of the present invention comprises:
(a) preparing 3 premixture comprising
(1) from about 25% to about 35% by weight wheat
gluten,
(2) from about SOe to about 65% by weight wheat
flour,-
(3) from 2°s to about 15°s by weight meat and bone
meal,
(4) from 3% to about 6°s by weight choice white
grease;
(5) from 0.2o to about 0.5% by weight methionine,
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~WO 95116367 PCT/US94/14027
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(6) from 0.1% to- about 1% by weight dicalcium
phosphate;
(b) combining the premixture with water to form a
secondary mixture, wherein the ratio of premixture
to water is in the range of from about 1.65:1 to
about 1.fl5:1;
(c) mixing the secondary mixture -in a ribbon mixer for a
period of time in the range of from about 4 to about
6 minutes, thereby obtaining a substantially
uniformly mixed dough, wherein said mixing is
carried out under conditians such that the
temperature of the secondary mixture and uniformly
mixed dough in the mixing operation are maintained
in the range of from about 20C to about 25C; and
(d) forming the uniformly mixed dough into a desired
shaped piece in a low shear extruder, wherein
extruder is operated at a speed in the range of from
about 50 to 60 RPM, the dough exit temperature is in
the range of from about 50C to about 60C, the exit
pressure is at least 600 _psig, and the specific
mechanical energy provided by the extruder is in the
range of from about 6 watt-hr./kg. to about 35
watt-hr./kg.
The present invention also relates to a cohesive; retort-
stable, shaped food piece prepared by the method comprising:
(a) preparing a premixture comprising
(1) from about 2D% to about 80% by weight gluten,
(2) from about 20% to about 80% by weight flour,
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(3) from- 0% to about 50% by weight meat and -bone
meal,
(4) from 0°s to about 9°s by weight fat,
(5) from-0s to about 0.7s by weight added sulfur,
(6) from 0s to about 2% by weight dicalcium
phosphate, wherein the weight percentage of the
premixture components are expressed as a
percentage of the premixture;
(b) combining the premixture with water toform a
secondarymixture, wherein the ratio -of premixture
to water :is in the range of from about 1.6:1 to
about 4.1;
(c) mixing the secondary mixture for a period of time
sufficient: to-obtaizi a substantially uniformly-mixed
dough andunder conditions such that the temperature
of the secondary mixture and uniformly mixed dough
in the mixing operation are maintained in -the range
of from about 15C to about 45C; and
(d) forming the uniformly mixed dough into a desired
shaped piece, wherein the -forming operation is
carried out in conjunction with low specific
mechanical. energy and high pressure conditions, and
under conditions such that the temperature of the
uniformly mixed dough in the forming operation is in
the range=of from about 40C to about 100C, and
wherein said shaped piece is cohesive and maintains
its shape when retorted.
The present invention is further illustrated,- but not
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limited by, the following examples.
FXAMPT~F~
Example 1-
A premixture containing 25 lb. wheat gluten, 65 lb. wheat
flour; 6 lb. choice- white grease, 2 lb. of methionine, 2 lb.
dicalcium phosphate, and 0_5 lb. of titanium dioxide is
initially prepared and blended for 2 minutes in a Buffalo
Mixer (which-is a ribbon blender). Water is added to this
blended preinixture at a weight ratio of 2:1 (blended
premixture:water) to prepare a wet mixture. The wet mixture
is blended in the Buffalo Mixer for-another 10 minutes to form
a dough.
The dough is removed from the mixer fed to a 4 inch
diameter, 5 zone Bonnot extruder using a "Bonnot #5"
(designated by Bohnot) screw shaft. The exit of the extruder
is fitted with a die having a single opening capable of making
a product in the shape of a bone.
The extruder is operated at 60 RPM (screw rotation speed)
and the body of the barrels is jacketed with cold water in the
first two zones (numerating the zanes starting from the feed
inletto the exit of the extruder) with nothing jacketing the
last 3 zones. The dough is fed into the extruder at a rate as
fast as the rotating screw can convey it away from the feed
inlet -(this is known as "choke-fed").
After-operating for about 5 minutes the process reaches a
state of equilibrium. The dough is being fed at about 2D0
kg./hr. The exit temperature of the product is 170°F (62°C)
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and the pressure, as measurecT at an outlet. immediately before
the die-assembly; is approximately 600 psig.
As the extrudate emerges from the die it is cut .in pieces
having a thickness of approximately 1/8 to 3/B inch. The cut
pieces are conveyed away from the pelletizer by a cool air
stream which facilitates transfer-and prevents the cut pieces
from adhering to each other. The collected cut pieces are
dried in a Proctor and Schwartz dryer for 2 hours until their
overall moisture content is less than 12°s w/w basis. =
The dried cut pieces are-placed in cans of pet food along
with other components, such as meat pieces and gravy. The
amount of cut pieces' in each can is 3a and the gravy (which is
essentially 95% water) comprises 50 wt. % of the can contents.
The overall moisturecontent- of the .canned -ingredients is
approximately 80%. The cans are sealed and retorted at 250°F
for 65 minutes. The resulting retorted canned contents
include the ~~bone-shaped~~ extruded pieces- The bone-shape of
the extruded pieces- is essentially the same shape as the
opening in the die. The ~~bone-piece" can be handled without
losing its integrity.
Fxamnle 2-
A dry mixture consisting of 283 lb. wheat gluten, 318 Ib.
meat and bone meal, 353 lb. wheat flour, 60 lb. choice white
grease, 21 Ib. methionine, 21 lb. dicalcium phosphate, and 4
lb. of titanium dioxide is blended for 2 minutes in a Buffalo
Mixer (which is a ribbon blender). To 250 lb. -of this
mixture, 125 1b. of water is added. The ~~wet mixture~~is then
blended in the Buffalo Mixer for another 10 minutes.
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The wet mixture (!'the dough") is now removed from the
mixer and ready to be fed to the extruder. - The extruder used
is a ~1 inch diameter 5 zone Bonnot extruder using a "Bonnot
#S" (designated by Bonnot) screw shaft. The exit of the
extruder is fitted with a die consisting of a single
rectangular opening (a '!slit" shape) with the dimension of 1/8
inch width by 5/8" inch length.
The -extruder is operating at 40 RPM (screw rotation
speed) and the body of the barrels is jacketed with cold water
in the first two zones (numerating thezones starting from the
feed inletto the exit of the extruder) and saturated steam at
psi-g jacketing the last 3 zones. The dough is fed into the
extruder at a rate-as fast as the rotating screw can convey it
away from the feed inlet (this is also known as "choke-fed").
15 After operating for about 5- minutes at a rotating speed
of 40 RPM and dough fed in continuously, the entire process
has reached a state of equilibrium. The .dough is being fed at
about 300 kg./hr. The exit temperature of the product is
180°F (68°C) and the pressure, as measured at an outlet
immediately before the die-assembly, is approximately 390
psig
As the extrudate emerges from the die, it is pelletized-
by an attached multi-knife cutter. The cutting speed is set
sufficiently fast to produce cut pieces of thickness of-
approximately 1/2 to 1-inch long, resulting in rectangular-
pieces-. The kibble thus produced is then conveyed away from
the pelletizer by a cool stream of auto facilitate transfer
and toprevent the kibbles from adhering to each other. The
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collected -kibbles are then dried in a Proctor and Schwartz
dryer for 2 hours-until the kibbles has reached an overall
moisture of 8% w/w basis.
The dry kibble is now put into cans of pet foods along
with other.componerits, such as meat pieces and gravy. The
amount of kibbles in each can is 3% and the gravy (which is
essentially 95% water) is 50%; the overall moisture :of the can
content is 80%. The cans are-sealed and retorted at 250~F for
65 minutes. The resulting canned contents include '~flat-
shaped' extruded pieces. The cross sectional shape of the
extruded pieces is essentially the same shape as the opening
in the die. - The "flat-piece° can be .handled without losing
its integrity.
F~xam
A dry mixture ctnsisting of I90 lb. wheat gluten, 118 lb.
wheat flour, 20 lb. choice white grease, 7 lb. dicalcium
phosphate, 2 lb. of ;titanium dioxide, and 1 lb. of a aluminum
lake color (yellow #6), is blended for 2 minutes in- a Buffalo
Mixer (which is a ribbon blender). To 250 1b. of this
mixture, 125 1b. of water.is added. The 'wet mixture'! is then
blended in the Buffalo Mixer for.another 10 minutes.
The wet mixture ('the. dough") is now removed =from the
mixer and ready to be fed to the extruder. The extruder used
is a 4 inch diameter 5 zone.gonnot extruder using a "Bonnot
a #5~~ (designated by Bonnot) screw shaft. The exit of the
extruder .is fitted -with a die consisting of 9. circular
openings and each opening has a-diameter of 1/8 inch.
The extruder is 'operating at 57 RPM (screw rotation
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speed) and the body of the barrels is jacketed with cold water
jacketing all 5 zones. The dough is fed into the extruder at
a rate as fast as the rotating screw can convey it away from
the feed inlet (this is also known as "choke-fed").
After -operating for about 5 minutes at a rotating speed
of 57 RPM and dough fed in continuously, the entire process
has reached a state of equilibrium. The dough is being fed at
about 250 kg./hr. The exit temperature of the product is
155°F (54°C) and the pressure, as measured at an outlet
immediately before the die-assembly, is approximately 800
prig.
As the extrudate emerges from the die, it is pelletized
by an attached multi-knife cutter. The cutting speed is set
sufficiently fast to produce cut pieces of thickness of
IS approximately 1 to 1 1/2 inch long.- The "strand" kibble thus
produced is then conveyed away from the pelletizer by a cool
stream of air to facilitate transfer and to prevent the
kibbles from adhering to each other.- The collected kibbles
are then dried in a Proctor and Schwartz dryer for 2 hours
until the kibbles has reached an overall_ moisture of10% w/w
basis.
The dry kibble is now put into cans of pet foods along
with other components, such as meat pieces and gravy. The
amount of kibbles in each can is 3~ and the gravy (which is
essentially 95% water) is 50°s; the overall moisture of the can
contends 80°s. The cans are sealed and retorted at 250°F for
65 minutes. The resulting canned contents include "strand-
shaped" extruded pieces. The shape of the extruded pieces is
-,
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essentially circular in diameter and slightly longer than the
original extruded piece.. The ~~strand-piece~~ can be handled
without losing its integrity.
Exatn
A premixture containing 97 lb. wheat gluten meal, 128.25
lb. wheat feed flour, 4.75 lb. methionine, and -4.75 lb.
dicalcium phosphate:is initially hand dumped and blended in a
ribbon mixer for 3 minutes. To the initial mixture, 14.25 1b.
choice white grease -is added and blended for 5 minutes to form
the blended premixture. Water is added to the.- blended
premixture at a weight ratio of 2.37:1 (blended
premixture:water) ,toprepare a iaet mixture. The wet mixture
is blended in the ribbon mixer for an additional 5 minutes to
develop a uniform dough.
IS The dough is manually removed from the mixer and manually
fed to a 4~~ diameter; S-zone Bonnot extruder using a Bonnot #5
screw (the extruder is fitted with a 15 HP motor) . .The exit
of the extruder is -fitted with a die insertwith a single
opening capable of making a definitively shaped product (e_g_~
bone, fish, wedge). For optimum conditions, the extruder is
operated empty for at Least 10 minutes prior to the
introduction of the wet dough. This operating time serves as
a warm-up and facilitates achieving steady-state conditions
within five minutes of manufacturing.
The extruder is operated at 59 RPM (screw rotation speed)
and the body of the barrel is jacketed with cold water in the
first two zones (the numbering starts with the feed inlet and
ends at the exit of the extruder). The third and fifth zones
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of the extruder are left at ambient conditions and the fourth
zone is steam jacketed. The dough is choke-fed into the
extruder. By "choke-fed~~ it is meant that there is more
material in the extruder hopper than the screw can convey
through the barrel instantly.
Within five minutes the process achieves steady state
conditions. The -dough is fed at about 225 kg./hr and exits
the extruder at a temperature between 65-70°C under a pressure
between 400-600 psig. Both the temperature and pressure are
measured immediately before the extruder outlet.
As the extrudate exits the die assembly, it is face-cut
to form pieces having a thickness of approximately 1/8 to 3/8
inch. The cut pieces are conveyed via an air-cooled conveyor
with a wire.mesh belt. The cool air reduces stickiness due to
evaporative flashing. The air-coaled pieces are collected in
wire mesh trays and dried in a Proctor & Schwartz batch oven
for 2_5 hours at 93°C or until the moisture content is less
than -1D% on a wet basis. The product is dried for stability
during storage but can be used in a canned product without the
preliminary drying.
The dried, shaped pieces are included as a component in
canned-dog food with other dog food components, including meat
and gravy. The shaped, extruded piece is included as 3% of
the final can weight, including gravy. The ratio of gravy to
component is generally about 48.52 (gravy:components). The
' canned components and gravy are sealed and retorted for 65
minutes at 120°C. The final product includes the retort
stable shaped pieces in a chunk and gravy matrix. The shaped
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pieces, upon hydration, weigh about 3 times their original
weight and have increased in -size by at least 25%. By "retort.
stable" it is meant that the -shaped piece can be easily
handled without changing shape, breaking apart, or losing the
identity of the original shape.
