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Claims  |
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What is claimed is:
1. A process for preparing a cohesive, retort-stable, shaped food piece,
which process comprises:
(a) preparing a premixture comprising
(1) from about 15% to about 65% by weight protein,
(2) from about 15% to about 65% by weight starch,
(3) from 0% to about 9% by weight fat,
(4) from 0% to about 0.7% by weight added sulfur,
(5) 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 secondary mixture and uniformly mixed dough in the
mixing operation are maintained in the range of from about 15.degree. C.
to about 45.degree. C.; and
(d) extruding the uniformly mixed dough into a desired shaped piece,
wherein the extrusion is carried out at a specific mechanical energy in
the range of from about 6 watt.multidot.hr./kg. to about 70
watt.multidot.hr./kg. and under a pressure of at least about 400 psig.,
and under conditions such that the temperature of the uniformly mixed
dough in the extrusion operation is in the range of from about 40.degree.
C. to about 100.degree. C., and wherein said shaped piece is cohesive and
maintains its shape when retorted.
2. A process according to claim 1 wherein the fat is in the form of choice
white grease, the sulfur is in the form of methionine, and wherein the
premixture comprises from about 15% to about 35% by weight protein, from
about 25% to about 60% by weight starch, from about 1% to about 8% by
weight choice white grease, from about 0.1% to about 1% by weight
methionine, and from about 0.1% to about 1% by weight dicalcium phosphate.
3. A process according to claim 2 wherein the premixture comprises from
about 20% to about 40% by weight of a wheat gluten protein source and from
about 30% to 75% by weight of a corn flour starch source.
4. A process according to claim 2 wherein the ratio of premixture to water
is in the range of from about 1.65:1 to about 2.5:1.
5. A process according to claim 4 wherein the secondary mixture is mixed in
a paddle mixer for a period of time in the range of from about 3 minutes
to about 8 minutes.
6. A process according to claim 5 wherein the premixture further comprises
from about 1% to about 30% by weight meat and bone meal.
7. A process according to claim 6 wherein the extruder is operated at a
pressure of at least about 500 psig.
8. A process according to claim 7 wherein the specific mechanical energy of
the extruder is in the range of from about 6 watt.multidot.hr./kg. to
about 50 watt.multidot.hr./kg., wherein the extruder is operated at a
speed in the range of from about 45 to about 60 RPM, and wherein the
temperature of the dough exiting the extruder is in the range of from
about 45.degree. C. to about 90.degree. C.
9. A process for preparing a retort-stable, shaped food piece, which
process comprises:
(a) preparing a premixture comprising
(1) from about 25% to about 35% by weight wheat gluten,
(2) from about 35% to about 65% by weight corn flour,
(3) from about 3% to about 6% by weight choice white grease,
(4) from about 0.2% to about 0.5% by weight methionine,
(5) from about 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 1.85:1;
(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 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 20.degree. C. to about 25.degree. C.; and
(d) extruding the uniformly mixed dough into a desired shaped piece,
wherein the 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
60.degree. C. to about 80.degree. C., 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.multidot.hr./kg. to about 35
watt.multidot.hr./kg.
10. A cohesive, retort-stable, shaped food piece prepared by the process
comprising:
(a) preparing a premixture comprising
(1) from about 15% to about 65% by weight protein,
(2) from about 15% to about 65% by weight starch,
(3) from 0% to about 9% by weight fat,
(4) from 0% to about 0.7% by weight added sulfur,
(5) 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 secondary mixture and uniformly mixed dough in the
mixing operation are maintained in the range of from about 15.degree. C.
to about 45.degree. C.;
(d) extruding the uniformly mixed dough into a desired shaped piece,
wherein the extrusion is carried out at a specific mechanical energy in
the range of from about 6 watt.multidot.hr./kg. to about 70
watt.multidot.hr./kg. and under a pressure of at least about 400 psig.,
and under conditions such that the temperature of the uniformly mixed
dough in the extrusion operation is in the range of from about 40.degree.
C. to about 100.degree. C., and wherein said shaped piece is cohesive and
maintains its shape when retorted.
11. A retort-stable, shaped food piece prepared by the method comprising:
(a) preparing a premixture comprising
(1) from about 25% to about 35% by weight wheat gluten,
(2) from about 35% to about 65% by weight corn flour,
(3) from about 3% to about 6% by weight choice white grease,
(4) from about 0.2% to about 0.5% by weight methionine,
(5) from about 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 1.85:1;
(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 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 20.degree. C. to about 25.degree. C.; and
(d) extruding the uniformly mixed dough into a desired shaped piece,
wherein the 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
60.degree. C. to about 80.degree. C., 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.multidot.hr./kg. to about 35
watt.multidot.hr./kg. |
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Claims |
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Description |
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FIELD OF INVENTION
The present invention relates to a process for preparing a retort-stable,
extruded, shaped food piece which is cohesive and maintains its shape when
retorted. The present invention further relates to the retort-stable,
extruded, shaped food piece prepared by the process of the present
invention.
BACKGROUND OF INVENTION
Pet owners typically have a great deal of affection for their pets. Many,
in fact, consider their pets to be members of their families, and treat
them accordingly by indulging 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 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 term proteinaceous material refers to glutens such as wheat
gluten, corn gluten, rice gluten, and other types of cereal grain glutens
known to those skilled in the art; proteinaceous material obtained from
other sources such as defatted oil seed protein material; dried eggs;
whole corn; wheat germ meal; dehulled soy meal; meat and bone meal; and
other known proteinaceous sources. The term farinaceous material refers to
cereal flours such as wheat flour, corn flour, rice flour, oat flour, and
other types of cereal flours known to those skilled in the art; ground
hard wheat; ground whole corn; and other types of ground cereal-based
grain material.
One problem in preparing such extruded, 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 to a 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 have to maintain a distinct and definite shape when subjected to
a retort operation.
The extruded shaped pieces of the present invention do not have such a
striated texture, however, but instead are, for the most part, cohesive.
Until now, extruded 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 shaped piece 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 invention are useful only when they are
retort-stable, i.e., do not dissolve upon hydration and/or retorting, but
maintain their desired shape. The present invention provides such a piece,
as well as a process for its preparation.
BACKGROUND ART
There are numerous processes known in the art for producing shaped,
extruded, edible proteinaceous products.
U.S. Pat. No. 3,968,268, issued Jul. 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 10 to 50%, is subjected to working under
effective mechanical pressure with added heat 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 teach that extruded proteinaceous materials
which are extruded at temperatures of 180.degree. F., 210.degree. F., and
230.degree. 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. Pat. No. 3,965,268, issued Jun. 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 preparing 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
said proteinaceous material of a sulfur-containing organic compound
selected from the group consisting of cysteine hydrochloride,
D,L-methionine, sodium lignosulfonate, thiamine mononitrate, 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.degree. F.;
mechanically working the heated mix at a pressure substantially above
atmospheric pressure; and expanding the mix by suddenly releasing the
pressure. 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 shaped edible piece of the present invention.
Furthermore, the process taught by Stocker et al. 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 and 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
prepared 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 and 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, shaped
food piece which is cohesive and maintains a definite and distinct shape
and integrity when hydrated and/or retorted.
These objects are accomplished by the invention described herein.
Unless otherwise specified, the weight percentages provided herein for the
components of the premixture are on a wet basis.
SUMMARY OF THE INVENTION
The present invention relates to a process for preparing a cohesive,
retort-stable, shaped food piece, said process comprising:
(a) preparing a premixture comprising
(1) from about 15% to about 65% by weight protein,
(2) from about 15% to about 65% by weight starch,
(3) from 0% to about 9% by weight fat,
(4) from 0% to about 0.7% by weight added sulfur,
(5) 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 secondary mixture and uniformly mixed dough in the
mixing operation are maintained in the range of from about 15.degree. C.
to about 45 .degree. C.; and
(d) extruding the uniformly mixed dough into a desired shaped piece,
wherein the extrusion 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 extrusion
operation is in the range of from about 40.degree. C. to about 100.degree.
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.
DETAILED DESCRIPTION OF THE INVENTION
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 15% to about 65%, preferably from
about 15% to about 35%, more preferably from about 20% to about 30% by
weight protein; from about 15% to about 65%, preferably from about 25% to
about 60%, more preferably from about 30% to about 55% by weight starch;
from 0% to about 9%, preferably from about 1% to about 8%, more preferably
from about 3% to about 6% by weight fat; from 0% to about 0.7%, preferably
from about 0.01% to about 0.5%, 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% dicalcium phosphate.
The protein present in the premixture of the present invention may be
derived from any source known to those skilled in the art, and is
preferably derived from wheat gluten. It is believed that other protein
sources, such as corn gluten, may work in the present invention as well.
Examples of other protein sources believed to be useful in the present
invention include, but are not limited to, those protein sources listed in
Table I below. Table I also includes an approximate description of the
amount of protein, starch (also stated as "carbohydrate"), fat, and
moisture each protein source can contribute to the premixture. These
protein sources may also be combined with each other in the premixture.
TABLE I
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Sources of Protein and Starch that may be used in premixrure:
MOISTUR PROT FAT CORBOH
INGREDIENT % % % %
______________________________________
CRACKD PEARLED
11.194 12.584 1.724
70.987
BARLEY
CORN FLOUR 9.438 7.339 2.111
79.202
CORN GERM MEAL
10.631 12.077 0.919
60.732
CORN STARCH 9.850 2.517 0.195
87.125
CORN YELLOW 14.201 8.692 3.600
69.807
CORN 14.500 8.110 3.600
70.290
OAT FLOUR 8.650 15.300 6.100
66.876
FEEDING OATMEAL
7.507 14.427 7.700
66.416
CORN GLUTEN 10.841 61.694 5.272
19.619
MEAL
BREWERS RICE 11.559 9.027 0.610
76.704
RICE HULLS 9.162 3.405 8.600
22.966
CORN 12.431 8.727 4.730
70.642
GROUND SOYBEAN
9.962 13.476 1.200
36.817
HULLS
SOYBEAN MEAL 11.652 45.290 2.575
30.626
DEHULL SOY MEAL
10.954 48.818 2.820
28.339
SOY FLOUR 5.251 53.650 2.551
34.328
SOY FLOUR 5.505 53.357 1.397
29.583
SOY PROTEIN 6.534 66.261 0.568
17.908
CONC.
SOYBEAN GRITS -
7.945 52.901 1.100
28.647
50%
SOY FLOUR 5.799 52.693 2.469
30.186
TEX SYBN FL 7.850 50.000 1.000
31.950
TVP 8.980 51.400 1.680
29.080
WHEAT 12.168 11.394 1.600
72.506
WHEAT FEED FL 12.684 14.349 2.420
68.010
WHEAT FEED FL 11.677 11.823 1.865
72.623
WHEAT FEED FL 5.881 13.709 2.757
75.756
WHEAT BRAN 13.802 17.473 3.274
49.159
WHEAT GERM 12.786 27.136 7.669
44.935
MEAL
WHEAT MIDDLINGS
12.576 16.337 3.591
54.452
WHEAT 10.195 13.856 2.960
68.526
PELLETED WHEAT
12.042 15.975 3.591
55.348
MIDDS
WHEAT FEED FL 10.990 15.030 3.390
67.733
WHEAT FEED FL 11.984 17.306 3.390
64.716
WHEAT GLUTEN 9.100 78.990 0.818
9.819
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Wheat gluten is the preferred source of protein in the premixture of the
present invention. This is because wheat gluten has a relatively high
protein concentration (79%) and is therefore a good protein source.
Wheat gluten is a concentrated natural protein in the form of a 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 any particular protein source used to prepare the
premixture of the present invention will be that amount necessary to
provide a protein content in the premixture in the range of from about 15%
to about 65% by weight, and will be dependent upon the particular protein
source utilized and the protein content of the particular source. The
preferred wheat gluten, which has a protein content of 79% by weight, will
comprise from about 20% 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 protein source may be provided to the premixture in the form of
isolated gluten added to the premixture, gluten inherent in the starch
source present in the premixture, and mixtures thereof.
The starch source used in the present invention may be derived from any
starch source known to those skilled in the art, including, but not
limited to, cereal flours obtained from known grains; ground hard wheat;
ground whole corn; and other types of ground cereal-based grain material.
Examples of flours useful in the present invention include, but are not
limited to, wheat flour, corn flour, oat flour, along with other types of
cereal flours known to those skilled in the art, and mixtures thereof,
with corn flour being preferred.
As with the protein source, the precise amount of any particular starch
source used in preparing the premixture of the present invention will be
that amount necessary to provide a total starch content in the premixture
in the range of from about 15% to about 65% by weight, and is dependent
upon the particular type of starch source being utilized and the starch
content of the starch source. For example, the preferred corn flour has a
starch content of about 79% by weight. When this preferred corn flour is
used, the premixture comprises from about 20% to about 80%, preferably
from about 30% to about 75%, more preferably from about 35% to about 65%
by weight corn flour.
The exact amounts of any particular protein and/or starch source required
to prepare the premixture of the present invention can be calculated by
using the approximate concentrations of protein and starch contained in
the specific type of ingredient, as stated in Table I, and determining the
amount of ingredient needed to achieve a total premixture concentration in
the above specified ranges.
The fat which may be added to the premixture of the present invention 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.
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 0% 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 by lubricating the
material flow through the extrusion 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 or 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 premixture
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 the premixture.
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 0.1%
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 0.1% 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 1% by weight of the premixture.
Other optional ingredients which may be added to the premixture of the
present invention include, but are not limited to, meat and bone meal,
edible fiber sources, nutritional supplements, coloring agents, and
flavoring agents.
When such optional ingredients are added to the premixture, the levels at
which they are added will vary depending upon the particular optional
ingredient. When meat and bone meal is included in the premixture it
typically comprises from 0% to about 50%, preferably from 1% to about 30%,
more preferably from about 2% to about 15% by weight of the premixture.
When adding the 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 final product,
which will be dependent upon the preferences of the particular formulator.
Such coloring and flavoring agents are typically added to the premixture
at levels of less than 1% by weight.
The premixture is next combined with water to form a secondary mixture. The
ratio of the premixture to water i | | |
