Note: Descriptions are shown in the official language in which they were submitted.
~ ~l 172899 ( SP-750A
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The present invention relates to a chopped egg
product and a process for producing the same.
Various types of egg products have been produced
for consumer use. Raw egg products have been prepared and
frozen in order that they may be subsequently thawed and
used in the same manner as fresh eggs. More recently,
cooked egg products have ~een produced which are suitable
for freezing with subsequent thawing and use. These cooked
-egg products are very desirable because of the con~enience
.
of simply thawing the pxoduct to permit use by the consumer.
These products and processes for their production are
generally described in the following U.S. Patents. I
U.S. Patent 3,510,315 describes a cooked egg product
in which the yolks are separately cooked.in a mo]d and
placed in a larger mold in which the uncooked e~g whites are
placed and cooked surround the yolk. I'he mixture is frozen
and a starch material is included in the whites to proYide
good freeze-thaw stability. A rozen product with an egg
yolk core surrounded by cooked egg white is obtained which
can easily he thawed and used by the consumer.
Improvements on the abo~e process for the production
of cooked frozen egg products are described in U.S. Patent
3,598,612 in which treatment of the yolk with an oxidizing
agent prevents discoloration of the interface area between
the yolk and white. U.S. Patent 3/598,613 describes a process
in which the yolks are preheated in a jet cooker to a solid
or semi-solid state, ground and then heated to form a solid
yolk product. U.S. Paten~ 3,798,336 and 3,711,304 describe
processes and apparatus for centering of the yolk body in
the egg whites before or during cooking to form a core o~
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egg yolk concentrically surrounded by the cooked whites.
These products can be conveniently thawed and sliced and
easily used by the consumer without cooking and peeling of
shell eggs.
The above types of cooked, frozen egg products have
been extensively used by restaurants because of the ease of
preparation. A recent addition to restaurants and institu-
tions engaged in mass feeding in this country, has been
the sala~ bar in which the customer can prepare his own salad
10- -with ingredients of his own choosing. A popular ingredient
at these salad bars is chopped or diced eggs which can be
sprinkled on the salad by the customer. Obviously~ the
cooking and chopping of eggs requires an extensive amount
of preparation, in addition to the fact that chopping usually
smears the yolk over the egg white particles resulting in
a pasty mess the consumer does not readily associate with
chopped eggs. In addition, when whole eggs are cooked, they
also suffer from problems with green discolora~ion of the
yolk surface which is visible in a chopped egg product since
the particles are exposed by ~irtue of being chopped up or
diced.
While the cooked, frozen egg products described
above avoid many of the discoloration problems associated
with whole eggs, nevertheless, these products also present
a poor appearance if they were simply thawed and chopped or
diced since the yolk readily smears onto the whites. A
need, therefore, exists fox a chopped frozen egg product
without significant smearing of the yolks on the whites,
which has a smooth texture, and may be readily thawed and
used by the consumer as an ingredient in or as a condiment
for foods.
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SP-750~
289~
Canadian ~pplication ~erial No. 382,077,
filed July 20, 1981, discloses a chopped egg produc-t
of highly desixable characteristics in which smearing of
tha yolk during chopping i~ avoided by carrying out the
chopping at a critically defined temperature range. The
process disclosed therein involves a single stage heating
step in which the yolks and whites are separately heated to
coagulate them prior to chopping.
It would be highly desirable to employ a process in
which the yolks and whites can be coagulated on a continuous
basis. In evaluating means for the continuous or dynamic
coagulation of the yolks and whites, it was determined that
the shear forces normally encountered in the dynamic heating
of fluids adversely effect the texture of the yolks and the
whites and if the temperature was increased during dynamic
heating to effectively coagula~e the yolks and whites, the
yolks and whites would still mai~tain a soft s~ate.
Accordingly, it was determined that dynamic or con-
tinuous heatiny could be used only if it was usad for pre-
heating of the ~olks and whites and cArried out below acritically defined product temperature. Dynamic preheating
of the yo~ks and whites is followed by heating ox maintaining
the product at a given temperature under static conditions to
effectively coagulate the yolks and whites to a substantially
firm texture and provide the reguisite texture needed for
subsequent freezing and chopping of the yolks and whites.
It is, therefore, an object of the present invention
to provide a cooked frozen chopped egg product which avoids
significant smearing of the yolk on the choppQd egg white
particles.
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It is also an object o~ the present invention to
provide a cooked and frozen chopped egg product which employs
a dynamic or continuous cooking process for preheating of the
yolks and whites for faster cooking time with greater-energy
savings~
It is also an object to provide a cooked and frozen
chopped egg product in which the yolk is a bright yellow
with an absence of discoloration.
It is also an object to provide a cooked and frozen
1~- ~chopped egg product which has good freeze-thaw stability
. ...................... .
without significant deterioration of the yolks and whites
during storage.
It is also an object to provide a cooked and frozen
chopped egg product which has a smooth but firm texture
without significant sticking or clumping,of the particles of
yolks and whites.
It is a further object to provide a unique process
for the production of a cooked a'nd frozen chopped egg product
which meets the above objectives which is reliable and con-
venient to practice on a commercial basis.
Summary o~ the Invention
These and other ob~ects are achieved in the present
invention which pro~ides a unique process for the production
of a cooked and frozen chopped egg product.
~ he present process comprises dynamically preheating
egg yolks to a product temperature which does not exceed
183F and egg whites to a product temperature which does
not exceed 167F followed by static heating of egg yolks and
whites at and for a period of time sufficient to coagulate or
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effectively cook the yolks and,the whites to a substantially
firm texture. The separately cooked yolks and whites are
then frozen~ A chopped egg mixture is formed by simultaneously
or sequentially chopping the rozen whites at a critical
temperature range of between about 22 - 30F. to provide a
chopped egg mixture in which minimal smearing o the yolk
on the whites occurs during chopping and the mixture has a
smooth but firm texture. The chopped mixture can then be
refrozen and sQld in this fashion for use by restaurants or
-institutions as a food condiment. The product represents a
. . .
distinct improvement over cooked, chopped, shell eggs in
appearance and texture as well as convenience to the user
of the product.
A significant factor in the above process which
provide the chopped egg product with such desirable appearance
and texture is the temperature range at which the simultaneous
or sequential chopping of the cooked yolk and white is carried
out. For example, if the temperature of the cooked egg
during chopping is above this tempexature range, extensive
2a smearing of the yolk and the white occurs resulting in a
product with an undesirable appearance. By contrast, at a
temperature below this range, the yolk and the white tend to
shatter or splinter resulting in an excessive amount of fines
which will also detract from the appearance o the mixture.
Likewise, :lt is important relative to the above
process that dynamic or continuous preheating be carried
out below a specifie~l product t~mperature, since it has been
determined i f this temperature is exceeded during dynamic
preheating subsequent static heating will not coagulate
the yolk and white to a firm texture and it will remain soft.
The combination of dynamic and static heating can improve
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the efficiency of the present process by reducing the overall
cooking time with yreater energy ~avings.
Descri tion of the Preferred Embodiments
P . . ~
In accordance with the present invention, pasteurized
liquid egg yolks a~d whites are obtained and placed into
separate containers for heating. It is not critical to the
present invention that the yolks or whites include additional
ingredients although various flavorings, spices, and/or
seasonings can be included if desired, It is extremely desirable
IQ however, to include a water binding material in the egg whites
since the product will be frozen and the addition of the water
binding material prevents syneresis during subsequent freezing
and thawing of the product. The water binding materials which
may be employed in the present invention include polysaccharides
or carbohydrates such as colloids, starches, cereals or ~lours
capable of absorbing and binding water~ Examples of suitable
materials include corn, tapioca, rice and potato starches, 10urs
and the like. Polysaccharides such as algins, carrageenans,
xanthan gum or various other colloids are also suitable as water
binding matexials. Carbohydrates which are particularly pre-
~erred are ood starches which have good freeze thaw s~ability
or po~sess the abili~y to retain watex in the egg whi~e portion
after the product has been frozen and subsequently thawedO The
water binding materials ~hould be present in the egg white por-
tion in an amount effective to prevent syneresis upon freezing
,and thawing, typically at levels between about 0.5 and 10~
by weight of-the egg whites. A preferred level is between about
2 and 4% by weight of the egg whites.
It is also possible, although not critical, to include
proteolytic enzymes or other additives in the egg yolk portion
~ ( c SP~750~
1 172~9~
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as described in U.S. Patent 3,S10,315, although such an
additive can be omitted entirely.
In the present inVentiQn~ a dynamic preheating step
is carried ou~ a~ a pxoduct tempexature below about 183F for
the egg yolks and 167F for the egg whites. As previously
noted, shear conditions, as normally encountered in the dynamic
heating of fluids, adversely affect coagulation of the yolks
and whites. Accordingly, dynamic heating can only be carried
- out in conjunction with a static heating step to effectively
Io. coagulate the yolks and whites and must be carried out below
certain temperatures in order for the static heating step to
effectively coagulate the yolks or whites t~ a substantially
firm texture.
Dynamic heating is intended to refer to a continuous
process as is normally employed for the heating of fluids and
it is not intended to limit the present invention by specific
apparatus necessary to carry out the dynamic heating step of
the present invention. Typically, various heat exchanger~ in
which steam is the primary heating source are suitable,
including heat exchangers indirectly heated by the steam or
those which utilize dixect steam injection to heat the slurry.
Typical steam pressures are between 0 - 25 psig, more typically
lQ - 20 psig. The most critical factor in the use of dynamic
preheating for the yolks and whites iB th~ adverse effect of
shear on ~exture of the cooked yolks and whitesO To minimize
~his problem it is essential to avoid dynamic preheating at a
product temperature above 183F for the yolks and 167F for the
whites. Typically, the product temperature range for dynamic
preheating should be between about 149-183~F for the yolks and
144-1~7F or the whites. This degree of heat treatment provides
` 11728g9 (: SP-750A
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sufficient heat to effectively complete ~oagulation of the
yolks and white~ to a substantially firm texture during the
static heating step. Dynamic heating also increases the
overall efficiency of the process by reducing the batch type
heating process in which the yolks and whites are coagula~ed
in individual containers to result in time and energy savings.
While it is not completely understood why exceeding the above
temperature limits during dynamic'heating prevents coagula'~ion
of ~he yolks and whites during subsequent static heating,
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nevertheless, the heated yolks and whites will not set up or
coagulate to a firm texture even with prolonged static heating.
The preheated yolks and whites are placed in separate
containers and statical'ly heated to complete coagulation of
the yolks and whites. Although the exact type of apparatus or
equipment used in the present process is not critical relative
to practice of the present invention for the static heating
step, a preferred container for heating is to place th0 yolks
and whites in flexible containers ox bags for immersion in the
cooking baths. This per,mits easy trans~er of the yolks and
whites thxough the heatin~ and reezing steps, followed by easy
removal o the frozen yolks and whites from the containers pr~or
to chopping. Heating of the yolks and whites is carried out in
a hot water or steam bath at a temperature of between about
165 - 210F, preferably 170 - 185~F for a period of time suffi-
cient to coagulate or effectively cook the egg yolks and whites
,to a substantially firm texture and typically about 10 to 20
minutes. _
The heated or cooked yolks and whites are then removed
from the cooking bath and cooled to facilitate rapid freezing
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31~28g9
either by spraying with cool water or dipping the containers
into a cool water bath. The heated whites and yolks are then
frozen as quickly as possible to a product temperature of
22 - 30F.
After freezing of the product to the above tempera-
ture the flexible containers with the frozen yolks and whites
are briefly ~armed to permit easy removal of the frozen yolks
and whites from the conkainers as an integral mass for choppi~g.
-This ~rief period of warming to permit removal fro~ the con-
tainer does not appreciably alter the temperature of the frozenyolks and whites from the desired range of about 22 - 30F.
The separately cooked and frozen yolks and whites at
a temperature range of 22 - 30F, preferably 24 - 28F are then
chopped by simultaneous or sequential feeding of the frozen
yolks and whites to a mechanical chopping or cutting device to
quickly subdivide the yolksand whites into small particles~ It
is not critical to the practice of the present process at wha~
weight ratio the yolks and whites are combined during chopping
and any weight ratio o~ white~ and yolks may be used. A pre-
20 ferred weight ratio for the chopped egg product is 30 to 40 partsof yolk to 70 to 60 parts of white. An especially preferred
ratio i5 about 30 parts of yolk to 70 parts of white since this
weight ratio somewhat approximates the ratio of white to yolk
normally found in whole eggsO Chopping may ~e carried out in
any type of ~ood cutter or similar device provided the tempera-
ture of the product during chopping does not rise above the
noted temperature range by exeessive heat generation during
chopping.
The chopped, cooked egg product is then rapidly
30 refrozen as a mixture even though only partial thawing on the
surfaces of the yolks and whites has taken place ~uring chopping.
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The chopped product is b~st frozen while in particulate form
before being placed in a container~ A preferred, though n~n-
limiting means for quick freezing the chopped yolk and white
mix~ure is by using an individual quick frozen sy~tem ~IQF~
of any type for quick freezing of the particulate eggs and
whites~
The resultant product, because of separate cooking
of the yolks and whites, has no discoloration from contac~
between the two and has a uniform, bright yellow color with
.. separate and identifiable pieces of egg white O The particles
of chopped white and yolks are xelatively uniform without signi-
ficant pasting or smearing of the yolk over the surfaces of
the egg white particles. The diced product is highly suitable
as a condiment for foodstuffs such as salads and represents a
significant improvement over similar con~iments prepared from
cooked shell eggs.
The followin~ Examples wil} serve as illustrative
but non-limiting embodiments of the present invention
Example I
To 30 pounds of pasteuriæed liquid egg whites is
added 7O4~ by weight of modified food starch, with the trade-
name "Consista" manufactured by A. E. Staley, D~catur, Illinois
and mixed.
The egg white, starch mixture and 30 pounds of
pasteurized egg yolks are separately preheated ~y pass~ng
through a heat exchanger which comprises a 15 ft, 0.209" I.D.
coil which is indirectly heated by steam at a pressure o lO ~ 20
psig in the surrounding chamber for the heat exch~nger coil. The
flow rate of yolks and whites through the coil is 2 lb/min. The
yolks are preheated to a product ternperature of 180F and the
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whites preheated to a product temperature of 160F. Following
preheating, 2 lb quantities of the egg white-starch mixture
and 2 lb quantities of the yolks are metered into flexible,
plastic bags. The bags are sealed and placed in a hot water
bath held at a temperature of 194F for 10 - 20 minutes. It
was observed that the whites and yolks cooked in this manner
coagulated satisfactorily and had the characteristically f-irm
texture of cooked egg yolks and whites. The bags containing
~ the coagulated yolks and whites are conveyed through a ~ater
spray of cool water at 70 - 75F and cooled.
The coagulated yolks and whites are then placed in
a blast freezer and frozen to a product temperature of
22 - 30F.
The yolks and whites are removed from the ~lexible
bays by brief thawing of the mass of frozen yolks and whites
and 70 parts by weight sf the whites and 30 parts by weight of
the fxozen yolks are placed in a batch type cutting dev.ice
consisting of a rotating bowl and a set o vertically rotating,
high speeA cutting blades. The yolks and whites are chopped
for a period of 3 minutes.
The chopped egg product is then refrozen before
packaging by being passed through individually quick fro~en
system (IQF) to quick free~e the particles.
The egg product after chopping and freezing has no
significant smearing of the yolks on the particles of egg
whites and consisted of relati~ely uniform and distinct pieces
of yolks and whites. The chopped product is highly suitable
as a condiment ~or foodstuffs.
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~ 17289~ i
Example II
To 30 pounds of pasteurized liquid egg whites is
added 7.4% by weight of moaified food starch, with the
tradename "Consista", manufactured by A. E. Staley, Decatur,
Illinois and mixed.
The egg whlte starch mixture and 30 pounds of
pasteurized egg yolks are separately preheated by passing
through a heat exchanger which comprises a 15 ft. 0.209"
I.D. coil which is indirectly heated by steam at a pressure
-of 10 - 20 psig in the surrounding chamber for the heat
....
exchanger coil. The flow rate of the yolks and whites through
the coil is 2 pounds/minute. The yolks as preheated to a
product temperature of 194~F and the whites preheated to a
product temperature of 176F. Following preheating 2 lb.
quantities of the egg white starch mixture and 2 lb. quantities
of the yolks are metered into flexible plastlc bags. The
bags are sealed and placed in a hot water bath held at a
temperature of 194F. for 10 - 20 minutes. The yolks and
whites would not set up to form firm coagulated yolks and
whites and were judged to be unsuitable for further freezing
and processing to form a frozen diced egg product.
Having described the above invention with reference
to the above specific embodiments, it is to be understood
that numerous variations can be made without departing from
the spirit of the invention and it is intended to include such
reasonable variations and equivalents within the scope of the
present invention.
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