Note: Descriptions are shown in the official language in which they were submitted.
~07373~
BACKGROUND AND PRIOR ART
During recent years, -food scientists have devoted much
of their time to developing methods for preparing acceptable
meat-like food products from a wide variety o~ secondary
plant and animal sources. To be acceptable, a food product
must be both bland and have a meat-like texture. One such
method involves e~trusion of a moist proteinaceous material
in the form of a plastic mass, under elevated conditions of
temperature and pressure, through an orifice into a region
of lower pressure to form an expanded porous protein-containing
product. This general method is exemplified by the processes
of U.S. Patent Nos. 3,102,031; 3,480,442~ 3,488,770 and
3,812,267. Protein extrudate produc~s thus obtained are
characterized by their tough, resiliellt, expanded, open-
cellular, rope-like structure made up of interlaced, inter-
connected pores and channels of varying width and thickness
having a bulk density of about 220 to 1500 grams per liter
,j _
on a weight basis when dried to less than 10 percent moisture.
When these protein extrudates are pro~erly hydra~ed, for ~ .
instance in boiling water, they will absorb several times
their dry weight in liquid and develop a chewy texture
somewhat similar to cooked lean meat. ~uch hydrated products
have been used extensively as a partial meat replacement in
such food products as chili, stew, meatloaf and the like.
Although these extrusion products represent a slgnifi-
cant advance in the art, they do possess several inherent
qualities, such as uneven texture and undesirable organoleptic
properties, which have limited their general use as a total
replacemen~ ~or real meat proteins. For example, it is
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` known in the extrusion art that ~esirable mea~-like texture
is dependent upon the degree of ~rotein expansion and the
; amount of water absorbed by the extrudate during hydration.
Protein extrudates which are overly expanded, ie., those
having a bulk density much below a~out 220 grams per liter
on a dry weight basis, are generally regarded as having,
when hydrated, a spongy or very porous structure which is
too soft to resemble meat. Conversely, a product which has
not been sufficiently expanded is too hard and dense to
resemble meat. Due to the porous expanded structure of the
extrudates, they have the ability to absorb large amounts o
water and this creates a problem of moisture control. A
protein extrudate which contains too much water is normally
too mushy, and a protein extrudate which contains too little
water is normally too tough to resemble meat. Unfortunately,
i~ is difficult tO control the moisture content of the
hydrated extrudates, and the produçts which result are not ~
totally satisfactory in their meat-like texture. - ~;
In addition to the above textural defects, the protein
extrudates prepared from crude proteinaceous ma*erials
inherently contain undesirable water soluble constituents,
such as carbohydrates, salts, flavor and odor components,
which are not normally associated with cooked meat produc~s.
One means of eliminating these objectionable materials is to
extensively purify the proteinaceous starting materials
prior to the preparation of the protein extrudates. This
prior processing, however, is costly, time consuming and
results in loss of valuable proteins.
Some of these flavor problems can be obviated by the
water extraction procedures described in U S. Patent Nos.
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3,142,571 and 3,870,805. These procedures take advantage of
the fact that the protein, following a cooking step such as
by pressure cooking or by extrusion, is denatured and
relatively water insoluble. Thus, the objectionable water
soluble materials mentioned above, which are trapped within
the extrudates' interstitial spaces or pores, can be partially
removed there~rom by aqueous extraction without serious loss
of the protein. Removing water soluble materials desirably
increases the extrudates' relative protein content to at
least about 70 percent on a dry weight basis and allows the
extracted protein extrudate to be classi~ied as a textured
protein concentrate. However, due to the relatively dense
nature of the porous protein extrudates which has been
essential to development of meat-like texture, it has not
previously been possible to completely remove all undesirable
water soluble components, and the resulting products have
therefore not been completely bland. In additîon, the water
; content of these hydrated, water extracted protein extruda~es
is difficult to control without costly and time consuming
mechanical water adjusting means and the texture thereo is
usually either too tough or too soft to closely resemble
real meat.
- SUMMARY OF THE INVENTION
... ...
It is thereore considered highly desirable to employ a
low cost efficient process to provide an accep~able textured
protein product without the inherent disadvantages of the
~ prior art processes described above
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In accordanee wi~h the presen~ in~ention, a novel
process is provided for the preparation of a textured protein
concentrate product which has improved meat-like texture and
bland flavor. The basic process utilized includes aqueous
solvent extraction of water soluble constituents from protein
extrudate containing such constituents and the present
invention provides an improvement in said basic process
; which comprises utilizing a protein extrudate having a
density of about 85 to 150 grams per liter on a dry weight
basis and extraction at a pH between about 5.5 and 6Ø
DESCRIPTION OF THE II~VENTION
' ~'"
The protein extrudate useful in this invention may be `
in the form of pieces or chunks whieh are generally regarded
as overly expanded products having a bulk density of between
about 85 and 150 grams per liter on a dry weight basis after
drying to less than 8 percent moisture. Preferably the
density will be between about 90 and 115 grams per liter on
a dry weight basis. Much above about 150 grams per liter,
the hydrated aqueous extracted protein extrudates are inherently
too dense, and water soluble constituents cannot be effec-
tively removed. Below about 85 grams per liter, the extru-
date products possess little, if any, meat-like texture.
Useful protein extrudate may be prepared from crude
proteinaceous materials containing on a weight basis about
35 to 80 percent protein and about 15 to 50 percent of other
water soluble constituents, such as carbohydrates, salts,
flavor and odor components. The proteinaceous materials may
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` 1073734
be obtained from both plant and animal sources including
oleaginous seeds, microbial and yeast ~ermen~s, cereal
grains, mixtures thereof and the like. Solvent extracted
leguminous seed materials such as hexane defatted soybean
materials are particularly satisfactory.
The proteinaceous material is admixed with about 9 to
18 percent of added water on a weight basis to form a moist
proteinaceous mixture. Preferably, the added water will
amount to about 11 to 16 percent on a weight basis. The
moist mixture is then passed through a cooker-extruder
equipped with a 50 horsepower motor, a~ a feedrate of about ~ .
200 to 400 pounds of proteinaceous material per hour and
preferably from 250 to 350 pounds af pro~einaceous material
per hour, while being subjected to elevated conditions of
temperature and pressure in the extruder, and is forced out
of the extruder through a die orifice into a substantially
atmospheric temperature and pressure environment. Feedrates
may be correspondingly adjusted for extruders equipped with
different horsepower ratings, as is well known by those
skilled in the art. The temperature in the extruder will
usually vary between about 100C. to 165C. at the die.
Preferably, the temperature will be between about 115C. and
140C. at the die. Pressures that may be employed at thç
die are in the range of 100 p.s.i, to 300 p.s.i. As the
; 25 extrudate emerges from the extruder's die orifice into the
environment o-f lower pressure, the water therein becomes
highly volatile and ~lashes of, causing the extrudate, as
measured in cross section, to expand by 20 to 300 percent
; and to partially dehydrate. The extrudate is then cut into
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pieces or chunks o-f about 1 to 2.5 inches in length, by a
rotating cutter located adjacent the extruder's die orifice.
To remove a major portion of the water soluble con-
stituents from the protein extrudate pieces produced as
described above, they are contacted with an aqueous solvent
; having a pH between about 5.5 and 6Ø Preferably, the pH
is about 5.7. Using these pH extraction conditions, the
aqueous solvent-contacted protein extrudate emerges after
the aqueous solvent extraction step containing about 85 to
87 percent moisture and at least about 70 percent protein on
a dry weight basis to provide a textured protein concentrate
product with improved meat-like texture and a bland flavor.
A protein concentrate is defined in the art as a protein
product containing at least about 60 to 70 percent protein.
At a pH much above about pH 6.0, the protein extrudate of
this invention develops a soft mushy texture and an excess
moisture content o-f about 88 to 91 percent. At a pH much
below about pH 5.5, the protein extrudate develops an
undesirable tough, chewy texture with a dry woody mouthfeel.
The acid pH of the aqueous solvent is maintained by the
addition of any suitable acid SUC]I as citric, hydrochloric,
phosphoric, sulfuric and the like. Suitable acid buffers or
acid salts may also be used as long as they do not adversely
affect the taste or texture of the protein product.
In order to effectively remove particularly troublesome
` water soluble constituents such as carbohydrates and flavors,
; the temperature of the aqueous solvent used to contact the
protein extrudate pieces should be above about 65C. Pre-
ferably the te~nperature will be above about 85C.
.
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lt will be appreciated by those skilled in the art that
the above extraction step can be practiced as a batch or as
a continuous process. The concentration of materials and
contact times will be dependent upon the mode selected.
Thus 3 for example, in a batch process, a concentration ratio
of about 20 parts of aqueous solvent to one part o protein
extrudate, on a weight basis, has been used successfully. .-
Preferably the protein extrudate will be contacted, in a
batch process, with fresh aqueous solvent ln at least two
stages with one stage of at least about 8 to 1 parts of
aqueous solvent to protein extrudate solids, and a second
stage of at least about 15 to 1 parts of aqueous sol~ent to
protein extrudate solids on a weight basis. In a continuous
process, such as in a continuous counteTcurrent multistage
extraction process~ it is possible to reduce the ratio of
aqueous solvent to protein extrudate to at least about 8 to
1 on a weight basis and still achieve good extraction
efficiency.
Using the above described temperature and concentration
conditions, contact times as low as 20 minutes have been
used successfully in a batch process. Longer contact times
may be desirable to improve the extraction of particularly
troublesome water soluble constituents. In either the batch
process or the continuous process, the contact time in each
stage can be reduced by increasing the number o~ contact
stages.
It has been consistently observed with the relatively
dense prior art protein extrudates that it is necessary to
contact the extrudates with an aqueous solvent at a pH above
6.0 to produce products with somewha~ acceptable texture. At
~07~3~34
a pH below 6.0, these ex~rudates develop unacceptable ~ough,
- chewy textures and dry mouthfeel qualities. However, even
at a pH above 6.0, it is difficult to control the moisture
content of these products without costly and time consuming
water adjusting means. From what is known of the prior art
and experience with relatively dense protein extrudates, it
was indeed surprising to find that products could be prepared
which have improved meat-like texture and extremely bland
flavor using the overly expanded, relatively light, protein
extrudate of this invention. When the protein extrudate of
this invention is contacted with an aqueous solvent at a pH
above 6.0, the products are too soft and mushy to resemble
meat. In the pH range from about 5.5 to 6.0, however, the
products of this invention have desirable decreased water
retention properties and can be conveniently maintained by
this process at about 85 to 87 percent moisture by weight,
without costly mechanical water adjusting means. As a
result, these novel products can be combined, as-is, with
various flavoring ingredients, binders, colors and other 20 additives to completely replace meat in many types of meat
analogs. Due to the stress conditions applied to the
products during normal mixing, the textured protein concen-
trate products of the present invention are inherently
shredded or ruptured to provide a plurality of fibrous-like
masses which possess a desirable texture similar to real
meat. Such products are useful in preparing hamburger-like
meat patties, sausages, meatloafs and the like.
In order to further illustrate the novel aspecks of the
present invention, khe following examples are presented. It
should be recogni~ed that these examples are provided by way
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10'7;~'734
of illustration only and are not intended to limit in any
way the invention disclosed herein.
.
EXAMPLE 1
This example illustrates a typical ~reparation of
protein extrudate from soybean materials and the preparation
of textured protein concentrate therefrom using the instant
extraction process.
Commercially available defatted soybean flour from
which the oil had been hexane extracted and which contained
about 50 percent by weight protein and about 35 percent of
water soluble components was mixed witn about 16 percent by
weight of added water to form a moist proteinaceous mixture.
This moist mixture was then continously, at a rate ~f about
290 pounds of defatted soybean flour per hour, passed through I
a Wenger X-25 cooker-extruder equipped with a 50 h.p. motor
and a three hole die, each opening having an orifice diameter
of about 3/8 inch with a length to diameter ratio of 4Ø
As the material passed through the cooker-extruder, it was
subjected, near the discharge die end, to a temperature of ¦;
about 115C. and to a pressure of about 180 to 250 p.s.i.
and was discharged from the extruder's die orifices into a ~-
substantially atmospheric environment. The extrudate
emerged as a continuous expanded rope of proteinaceous
material having a very porous, open-cellular texture. The
expanded extrudate was then cut into about 1.5 inch pieces
or chunks by a rotating cutter located adjacent to the
extruder's discharge end~ The extrudate pieces were about
0.6 to 0.7 inch in diameter and had a bulk density of
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73~734
between about 104 to 123 grams per liter at a moisture
content of less than 8 percent by weight.
About 15 pounds of the protein extrudate pieces,
prepared as described above, were placed in a large open
kettle and were then contacted with an aqueous solven~ by
adding to the protein extrudate about 120 pounds of water
(which corresponds to an aqueous sol~ent to solids ratio of
about 8 to 1 on a weight basis) and about 550 ml. of 10
percent by weight phosphoric acid. The pH of the mixture
was about 5.7. The mixture was gently agitated for 20
minutes at 85C. and the water was drained from the extrudate.
About 170 pounds of fresh water was then added to the drained
extrudate (which corresponds to an aqueous solvent to solids
ratio of about 15 to 1 on a weight basis) and maintained at
85C. for 45 minutes at pH 5.7, by the addition of a suitable !
acid if necessary, under gentle stirring conditions and the
water was drained from the extrudate pieces. To reduce the
temperature of the extrudate an additional 170 pounds of
cold tap water at 18C. was added to the extrudate and
20 drained away after about 5 minutes to provide a textured ;~
protein product which contained about 85 to 86 percent `~ -
moisture and about 70 percent protein on a dry weight basis.
The textured protein concentrate so prepared was str~cturally
similar, in size and shape, to the protein extrudate starting
25 material, before the aqueous extraction step, but had a ~ ;
resilient, pliable, more open-cellula~, fibrous texture.
When placed in the mouth and masticated, the textured protein
concentrate of this example had an excellent che~y, meat- ~ -
like texture and a bland flavor.
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~073~73~1L
A hamburger analog patty mix was prepared from the
above textured protein concentrate by combining the fol-
lowing ingredients:
1000 grams textured protein concentrate
60 grams proteinaceous binder (such as
egg albumin)
180 grams flavors, seasoning, fats and color
These ingredients were mixed well and made into patties and
fried at about 176C. until cooked. These products were
then compared with natural hamburger and cubed steak fried
in a similar fashion. The products of this invention had a
texture which was closely similar to natural hamburger.
EXAMPLE 2
This example illustrates the preparation of protein
extrudates of different bulk densities and the effect of
bulk density on the moisture content, shear streng~h and `
mouthfeel of the textured protein concentrate.
Protein extrudates of varying bulk density were prepared
from defatted soy;bean flour containing by weight about 50
percent undenatured protein, about 20 percent water soluble
constituents and about 7 percent moisture in a manner
similar to Example 1 using the following extrusion condi-
tions.
Sample Feed rate % Moisture TDemp. Die Bulk Density
lbs./hr. added C. p.s.i. grms./liter
_ _,
1 250 15.4 119 160 114
2 250 12,~ 11~ 130 110
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3 310 12.~ 1~0 200 9
4 310 12.4 116 190 92
350 11.8 1~8 270 112
6 350 9.1 135 150 102
lAll extrudates were dried to less than 8% moisture.
~ One half pound of each of the above samples was then
contacted with 15 pounds of water containing lS ml. of 10
percent phosphoric acid at 85C. for 25 minutes and the
excess water was drained therefrom. The pH of this mixture
was about 5.8 to 5.9. Each of these samples was then com-
pared with commercially available protein extrudates which
were contacted with the aqueous solvent in the same manner.
The effects of bulk density are shown in the following Table
I.
Table I
Sample Bulk Density % Moisture Shearl Mouthfeel
grms./liter drained wt. lbs. -
1 114 83.8 319 ~ all samples 1 6 ~ `
2 110 85.9 304 \ have an exc~llent
3 96 85.6 310 ¦fibrous, chewy,
4 92 87.4 240 juicy mouthfeel
112 87.4 343 wi~h good bit~ $
6 102 84.7 310 elasticity ;
A 249 82.8 470 very coarse, dry.
B 269 80.6 S30 tough, 1aky, dry.
C 367 76.2 530 tough, flaky, dry.
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~1()>7373~
Shear strength was measured on ~he Allo-Kramer Shear
Tes~er as a measure of the maximum stress the material can
develop under the shearing force.
Supro 50A, a commercially available soy protein extrudate
from Ralston Purina Co.
B Vita Pro A-6, a commercially available soy protein extru-
date from Lauhoff Co.
~ ADM U-llO, a commercially available soy protein extrudate
from Archer Daniels Midland Co.
The data illustrated in the above table clearly shows
that, by increasing the bulk density of the protein extrudate
to much above about 200 grams per liter, a product is
produced which has undesirable texture and dry mouthfeel as
shown by the subjective mouthfeel qualities and supported by
the increased shear strength and decreased moistures. lt
should be noted that the impartial sensory panel which
~ evaluated mouthfeel qualities observed an undesirable soy
;~ note in all the commercial extrudate products treated in
this example. Within the preferred range of about 90 to 115
grams per liter, the products had an excellent fibrous
quality and a juicy meat-like mouthfeel and a bland flavor.
EXAMPLE 3
This example illustrates the effect of pH during
aqueous solvent contact of the protein extrudate on mouth~
feel qualities and shear strength of the protein extrudakes.
Five separate 10 pound batches of protein extrudate
were prepared and contacted with the aqueous solvent in a
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1C~73~34
similar manner as described in Example 1. To each batch of
protein extrudate and aqueous solvent there was added suffi-
cient 10 percent by weight phosphoric acid to adjust the
aqueous mixture to a selected pH value between 4.7 and 6.4.
After aqueous solvent contact, the protein extrudates were
merely drained without squeezing, mouthfeel was evaluated by
an impartial sensory panel, and shear strengths were measured.
The results obtained are found in the following Table II.
Table II
10 pH of Aqueous Shear* Mouthfeel
mixture lbs.
_~
4.7 460 tough, chewy, too dry
5.5 440 r all products have an excellent
5.7 - 5 8 335 ~ fibrous~ chewy, juicy mouthfeel
; 15 6.0 350 ~ with good bit ~ elasticity.
6.4 180 mushy, too soft, too wet
* Shear strength was measured on the Allo-Kramer Shear
Tester as a measure of the maximum stress the material can
develop under the shearing force.
From the results shown in the above table, it will be
observed that above a pH of about 6.0 the hydrated protein
extrudate of this in~ention develops shear strengths which
are markedly decreased and which decrease in a dramatic
nonlinear fashion with respect to pH change. Above pH 6.0 `
the texture of the protein extrudates was consistently too
soft and mushy to resemble meat. At a pH much below about
5.5, the protein extrudates were too dry and the texture was
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1073t7;~4 -
too tough and chewy to resemble meat. Within the pH range
from about 5.5 to 6.0, the products had de~irable mouthfeel
qualities and the texture was very similar to real meat.
The most desirable balance between mouthfeel and shear
strength was observed at pH 5.7-5.8.
EXAMPLE 4
This example illustrates the e-fect of temperature on
the extraction of particularly troublesome water soluble
constituents such as flavoring components from the protein
extrudate.
Three separate batches of protein extrudate were
prepared and contacted with an aqueous solvent as d,escribed
in Example 1. Each batch was extracted at a different
temperature from 20C. to 85C. The results are found in
the following Table III.
,~ ~
Table III
Temperature Flavor Evaluation
20C. Strong soy flavor
65C. Mild soy note
85C. Bland flavor
The results in the above table illustrate that a tempera-
ture of above about 65C. is required to produce an acceptable
product. Optimum extraction is achieved a~ a temperature
above about 85C.
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EXAMPLE 5
This example illustrates a counter~cur~ent extraction of
water soluble constituents from the protein extrudate.
Four batches of soy protein extrudate as prepared in
Example l were subjected to a s~lulated counter-current ex-
t~action usin~ an aqueous solvent to solids ratio of lO to l. .
Each batch was solvent contacted four times with an aqueous
solvent llaving a p~I of about 5~6 to S.7 for about 20 minutes
at 85C. To simulate counter-current extra tion, the extract- :
ing liquid from a preceding batch was used to contact each
next succeeding batch of extrudate and so on until each batch
had been contact~d four times. ~resh wa~er adjusted to pH 5.6
to 5.7 was used in the last contact stage of each batch. A ~.
true counter-current extraction was achieved in the last batch
to be solvent contacted. The protein extrudate pieces which ~.
emerged from the last batch were vexy bland in flavor and con~
tained about 70 percent protsin on a dry weight basis and about
86 percent moisture..~on a drained.w~ight basis.
This example clearly shows that undesirable flavor com-
ponents can be removed from protein extrudate using a counter-
current extraction at a low aqueous solvent to solids ratio. ~
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SUPPI.EMENT~RS~ DISCLOSURE
In the foregoing disclosure, there is described a novel
process for the preparation of a textured protein concentrate
product which has improved meat-like texture and a bland
flavour. The product may be obtained from a protein extrudate
containing water soluble constiuents by the aqueous solvent
extraction of such water soluble constituents from the extrudate.
An improved step in such an extraction process comprises the use
of a protein extrudate having a density of between about 85 to
150 grams per liter on a dry weight basis and the extraction is
carried out at a pH between about 5.5 and 6Ø
It has now been found that by using protein extrudates
having a density of between about 85 to 150 grams per liter
on a dry weight basis and carrying out the extraction at a pH
between about 4.4 and 6.0, there is obtained a variety of
textures. Thus, textures resembling tender lean portions of
beef, pork, poultry or shellfish can be preferentially obtained
by extracting the extrudates at a pH between about 5.0 and 6.0
while textures resembling fish can be preferentiallyobtained by
extracting an extrudate at a pH between about 4.4 and 5Ø
To remove a major portion of the water soluble
constituents from the protein extrudate pieces produced as
described hereinbefore, they are contacted with an aqueous
solvent having a pH between about 4.4 and 6Ø Using these pH
extraction conditions, the aqueous solvent-contacted protein
extrudate emerges after the aqueous solvent extraction step
containing about 80 to 87 percent moisture and at least about
70 percent protein on a dry weight basi~ to provide a textured ,
protein concentrate product with improved meat-like texture and
a bland flavor. A protein concentrate is defined in the art as
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a pxotein pxoduct con-taininy at least about 60 to 70 percent
protein. At a pll much ~ov~ about pH 6~0, the prot~in extru-
date of this invention develops a soft mushy texture and an
excess moisture content of about 88 to 90 percent. At a pH
between about 5.0 and 6.0, preferably a p~I between 5.4 and 5.9,
the protein extrudate develops a desirable texture similar to
the lean portions of beef, pork, poul~ry or shellfish. At a
pH between about 4.4 and 5.0, preferably a pH between about
4.4 and 4.8 the protein extrudate develops a desirable texture ;~
sLmilar to fish. At a pH much below about pH ~.4, the protein
extrudate develops an undesirable rubbery, tough, chewy texture
with an extremely dry woody mouthfeel. In the pH range fxom
about 5.0 to 6.0, the products of this invention have desirable
decreased water xetention properties, desirable ~exture resem- ;
bling beef, pork, poultry or shellfish and can be conveniently -
maintained by this process at about 85 to 87 percent moisture
by weight, without costly mechanical water adjusting means. In ;
the pH range from about 4.4 to 5.0, the products of this in-
.. :
; vention have desirable texture resembling fish/ especially tuna,
20 and can be conveniently maintained by this process at about 82 ~ ~
to 86 percent moisture by weight, without costly mechanical ~ -
:.. ..~ -
water adjusting means. ~; `
When placed in the mouth and masticated, the textured ;~
protein concentrate products of this invention have a chewy meat-
like texture resembling the texture of tender, lean cuts of beef,
pork, poultry or shellfish, and a bland flavour. Such products
are useful in preparing hamburger-like meat patties, sausages,
mea~-loafs~ lean sirloin, chicken loaf, lean pork, tuna-fish
cakes, shellfish-cakes and the like.
The invention is further illustrated by the following
examples which are provided by way of illustration only and are
not intended to limit in any way the invention disclosed herein.
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IS~M~IS 6
This example illustrates the effect of p~l ~uring aqueous
solvent contact Of the protein extrudate on mouthfeel qualities
and toughness values of the protein extrudates.
Eleven separate 10 pound batches of protein extrudate
were prepared and contacted with the aqueous solvent in a
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similar manner as described in Example 1. To each bateh of
protein extrudate and aqueous solvent there was added suficient
10 percent by weight phosphoric acid to adjust the aqueous
mixture to a selected pH value between 3.7 and 6.4. After
aqueous solvent contact, the protein extrudates were merely
drained without squeezing, mouthfeel and toughness values were
evaluated by an impartial sensory panel. The results obtained
are found in the following Table IV.
TABLE IV
pH of ~queous Toughness* Mouthfeel
Mixture Values
3.7 9.0 All samples at pH 3.7 to 4.2:
hard, dry, rough surface;
4.0 8.5 very dry and astringent;
very cohesive, compacts
4.2 8.5 when chewed; very tough and
rubbery; very high bite
resistance.
4.4 6.5 All samples at pH 4.4 to 4.8:
dry rough surface, drying
4.6 6.5 mouthfeel; cohesive; compacts
when chewed; tough; high bite
4.8 6.0 resistance.
5.0 6.0 Slightly rough surface; drying
mouthfeel; cohesive; compacts
when chewed; tough; spongy,
good bite resistance.
5.2 5.0 Slightly rough surface; drying
mouthfeel; cohesive; compacts
slightly when chewed; slightly
tough; grainy; good bite
resistance.
5.4 3.0 Slightly rough surface; slightly
juicy; good cohesiveness; good
bite resistance; fibrous.
5.7 2.5 Very slight rough surface; juicy;
good cohesiveness, tender, firm
chew; good bite resistance;
fibrous.
5.9 2.0 Soft surface; juicy; slight
cohesiveness; spongy; good bi~e
resistance, fibrous.
6.1 0.5 Samples at pH 6.1 and 6.3: soft
slippery surface; mushy; no
6.3 0.5 cohesiveness; very soft; very
low bite resistance.
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:
*Toughness values were determined by the impartial
sensory panel in the following manner. Panel members were
asked to rank the samples in ~heir amount of increasing
- toughness. This was done by assigning a number 9 to a sample
having the most toughness and a number 0 to a sample having
the least toughness and no bite resistance. Numbers between 0
and 9 were assigned to samples according to their relative
amounts of toughness.
From the results shown in the above table, it will be
observed that above a pH of about 6.0 the hydrated protein
extrudate of this invention develops toughness values which
- are markedlydecreased and which decrease in a dramaticnonlinear
fashion with respect to pH change. Above about pH 6.0 the
texture of the protein extrudates was consistently too soft
and mushy to resemble meat. At a pH much below about 4.4 the
protein extrudates were too dry and the texture was too tough,
rubbery and chewy to resembly meat. Within the pH range from
about 4.4 to 6.0, the products had desirable mouthfeel
qualities and the texture was ver~ similar to real meat. The
most desirable balance between moughfeel and toughness for
texture similar to beef, pork, poultry or shellfish was observed
at about pH 5.4 to 5.9. The most desirable balance between
mouthfeel and toughness for texture similar to fish was observed ;~
at about pH 4.4 to 4.8.
A tuna fish analog was prepared from the above textured
protein concentrate extracted at pH 4.4 to 4.8 by combining the
following ingredients:
1700 grams textured protein concentrate; and
250 grams fiavor, seasoning and fats.
These ingredients were mixed well, placed in a can and pasteurized
at 185F for 60 minutes. These products were then compared with
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canned tuna. ~he products of this invention had a texture
which was closely similar to natural canned tuna.
EXAMPLE 7
This example illustrates a comparison between the
products produced by this invention and the prior art products
produced by the processes described in United States Patents
Nos. 3,1~2,571 and 3,870,805 hereinafter respectively referred
to as McAnelly and Hayes.
A protein product was prepared substantially in
accordance with McAnelly in the following manner. Soybean flour
(550 g of 65 mesh) was mixed ~or three minutes in a mixer with ;-
450 g of water. The resulting dough was passed through a food ~
, .. .
grinder equipped with a 1/4 in. plate to form strands. The
resulting strands were placed on a screen in an autoclave. The
temperature in the autoclave was raised to 121C with live
steam. This temperature was maintained for 5 minutes. At the
end of this time the pressure was released within 1.0 to 1.5
minutes. The thus cooked strands were chopped in a food chopper
to obtain smaller pieces. About 100 g of the cooked, chopped ~-
strands were placed in a beaker containing 900 g of water
heated to 82C. The contents of the beaker were then stirred
occasionally for 15 minutes and the water was poured off and
replaced with an equal volume of fresh water at 82C. Again
the contents of the beaker were occasionally stirred for 15
minutes at which time the water was poured off and replaced
with an equal volume of fresh water at ~2C. This water was
allowed to remain in contact with the cooked pieces of product
for 3 minutes. At the end of this time, the water was poured
off and the product was drained without squeezing.
A second protein product was prepared substantially in
accordance with Hayes using a sinyle die extruder in the following
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~073'73'~
manner. Defatted soy flour (200 pounds) of protein
;concentration of about 50 percent and 60 pounds of water were
added to a blender. Sodium chloride (290 g), sodium hydroxide
(830 g) and calcium chloride (830 g) were dissolved in one
gallon of water and added to the blender. The material was
heated to 120F and blended for 20 minutes. The resultant
material was then introduced to a barrel-type extruder (a
"Wenger X-25 model"). The heat assembly section of the extruder
was designed as follows. One die was used having six 7/16 inch
circular orifices located around the periphery of the die, each
orifice having a length/diameter ratio equal to about 1.
The mixed material was fed to the extruder at a rate of
about 350 pounds per hour. Additional water at the rate of about
60 pounds per hour was added to the mixed material in the
extruder barrel. The retention time in the barrel of the
extruder was about 10 seconds. The screw conveyor located
inside the extruder barrel wa~ operated at about 320 rpm. The
temperature and pressure just ahead of the die was 135C and
200 psi, repsectively. After passing through the die the
mixture was discharged to the atmosphere.
~The result~ng extrudate (300 g) was slurried in 6 liters
-of water. The water was maintained at 82C for 5 minutes. The
slurry was then placed in a centrifuge operated at 2000 Gs to
remove excess water. The centrifuged product was again
slurried in water, as before, and centrifuged~
The protei~ product of this invention was prepared
substantially in accordance with Example 1 hereinafter referred
to as TPC.
The bulk densities of each of the products, before
aqueous leaching, were measured. The measured bulk densities
are found in the following Table V.
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.7~ * Trade Mark
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TABLE V
.
Product Bulk Density at Zero
Moisture, gI~ams/liter
McAnelly ~47.2
Hayes 364.0
TPC 9 2 . O ~ -
The above data clearly illustrates thak the prior art ~ -
products have much higher bulk aensities than the products of ~ ;~
~he present invention.
The above-prepared hydrated protein products were
evaluated for mouthfeel characteristics by an impartial sensory
panel and both toughness and hardness were measured. The results
obtained are found in the following Table VI.
TABLE VI
,::
Product Hardness*Toughness** Mouthfeel
(lbs) (lbs-in)
,.
McAnelly 111 1148 Very soft, mushy,
bread-like, no bite
resistance, soggy
and watery
Hayes 562 2670 Nonhomogenous texture,
some pieces tough and
rubbery, some pieces ~ -
mushy and mealy .
TPC 377 1390 Tender, fiberous, !
good bite resistance
and elasticity, fine
grained, porous,
juicy ;
*Hardness was measured on an Instron texturometer using
a 100 g sample as a measure of the maximum resisting force
generated by the sample.
**Toughness was simultaneously measured on the Instron
texturometer along with the hardness as the integrated area
under the hardness curve. Toughness is thus the measure of the
total work generated by the sample.
,
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* Trade Mark
.
, . : . .
`` 1~73~3~
From the results shown in the above table, it is clear
that the hydrated protein extrudate of this invention is
dramatically different than the prior art products in mouthfeel,
hardness and toughness. rrhe McAnelly product was too soft ancl
too mushy to resemble meat. Hayes product was nonhomogenous,
some pieces were too tough and too rubbery and other pieces
were too soft and mushy to resemble the tender lean portions of
meat. The product of this invention had very desirable
homogenous mouthfeel qualities and the texture was very similar
to the tender lean cuts of meat.
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