Note: Descriptions are shown in the official language in which they were submitted.
,553
This invention relates to an improved method and to improved
apparatus for marinating poultry and for enhancing the pick-up of marinade
`by poultry, such as chicken.
It has been determined that the flavor and texture of chicken, ~;
particularly of pieces of chicken to be fried, are enhanced when the chicken
pieces are treated with a marinade and when they pick up and retain the
marinade. Flavor enhancement results from the pick up of salts and other
additives which may be used in the marinade. Further, absorbed moisture
tends to result in a more moist texture in the finished cooked product
after frying.
Various methods have been employed to cause chicken pieces to
pick up and retain marinade. In one such process, chicken pieces have been
immersed in, and carried through a marinade for a period of time sufficient
to allow the chicken pieces to soak up some marinade. The amount of pick ;~
up is not constant in this process, and less than ~he desired amount of
pick up frequently results from the use of such a process. Further, the
time of immersion is lengthy and is frequently a bottleneck in continuous ~ ^
chicken processing.
In yet another method of marinating chicken pieces, a drum is
pacXed with chicken pieces and with some marinade, and the contents of the
drum are tumbled. Some marinade is picked up in such a process, but here .-
again it is a batch process which requires excessive handling and which does
not lend itself to continuous chicken processing. Further, the chicken
often gives up some of the marinade picked up in batch processing before
it can be breaded and frozen or otherwise suitably processed.
I have discovered a method by which poultry pieces can be made
to pick up greater volumes of marinade than is usually possible in similar
time periods with existing processes. I have determined that this may be
done on a truly continuous basis so that the marinating step in the process-
ing of poultry may be performed in-line with the other treatment steps,
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without being a bottleneck in a poultry processing line and while retaining
more of the marinade, with less handling, than is usually possible with
batch processes.
In accordance with my process, there is provided a method of
marinating poultry pieces) comprising cutting poultry into poultry pieces,
introducing said poultry pieces into an elongate continuous conveyor
assembly, maintaining liquid marinade in said conveyor assembly and contin-
uously replenishing the liquid marinade to maintain a predetermined liquid
level and concentration of marinade, conveying said poultry pieces through
said liquid marinade longitudinally from one end of said conveyor assembly
to the discharge end of said conveyor assembly, repeatedly lifting said
poùltry pieces out of said liquid marinade and dropping said poultry pieces
back into said liquid marinade as said poultry pieces are conveyed from ;~-~
one end of said conveyor to the other, thereby to work and agitate said
poultry pieces to enhance the absorption of marinade by said poultry pieces.
The lifting and the repeated dropping and tumbling of the poultry
pieces back into the marinade solution appears dramatically to increase the ~-~
rapidity of pick-up of marinade as compared simply to carrying the poultry
pieces through a marinade bath for the same time period. Although I am not
20 certain, this may well be attributable to the increased working and flexing ;` ~
of the poultry flesh and tissue making the flesh and tissue more receptive ~;
to the pick-up of marinade than it would otherwise be. In any event, the - ;
repeated lifting a-nd dropping of the poultry pieces from and back into the
liquid marinade causes the poultry pieces to pick up and absorb marinade
rapidly, thereby making it possible to marinate in-line in a poultry pro- `
cessing line and, when performed in a continuous conveyor, making it possible
to operate a poultry processing line on a truly continuous basis, eliminating
marinating as a bottleneck to continuous poultry processing.
Marinating apparatus in accordance with my invention comprises an
elongate trough and a continuous screw conveyor in said trough, said screw
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conveyor having a central hub and a plurality of ~lights spirally secured
to said hub, a plurality of lifting vanes and at least one lifting vane
positioned between each adjacent pair of flights and extending inwardly and
rearwardly with respect to the direction of rotation of said screw conveyor
from the peripheral edges of said flights to lift and to drop poultry pieces
disposed between said flights, discharge vanes at one end of said screw ~ q
conveyor for lifting poultry pieces upwardly~ said discharge vanes extending
inwardly from the periphery of at least one pair of adjacent flights and
inclining forwardly in a direction opposite from the direction at which the
10 lifting vanes are inclined, a discharge chute at one end of said trough
adjacent the end of the screw conveyor mounting the discharge vanes for
receiving poultry lifted by the discharge vanes, and in which said lifting
vanes extend rearwardly at an angle of from about 45 to about 60 degrees
from a plane including the outer edges of the vanes and the axis of said `-
hub, the peripheral edges of said flights and said lifting vanes being
positioned closely adjacent said trough whereby neither the flights nor ;
said lifting vanes are likely to cut into poultry pieces disposed in said
marinator assembly.
In this manner, poultry pieces are continuously marinated
20 effectively and rapidly. By providing a truly continuous process, the
poultry pieces are more quickly ready for subsequent treatment and freezing,
resulting in poultry which retains a greater amount of marinade with its
attendant advantages.
Further objects, features and advantages of this invention will
become apparent from the following description and drawings, of which
Figure 1 is a perspective view of a conveyor assembly of this
invention;
Fig. 2 is a cross-sectional view taken substantially along the
line 2-2 of Fig. l;
Fig. 3 is a cross-sectional view taken substantially along the
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line 3-3 of Fig. l; and ;~
Fig. 4 is a front view of a further embodiment of a lifting vane
of this invention.
Referring first to the drawings, a chicken marina~ing assembly 1
made in accordance with this invention is seen to include a trough 10
for containing liquid marinade M and
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a screw conveyor 12. The trough 12 ls generally semi-
cylindrical with generally vertical upper longitudinal edges.
The ends are generally flatO A cover 13 for sanitary pur-
poses may be used. Screw conveyor 12 mounts a plurality of
flights 14.
Flights 14 form a usual spiral configuration. They
are centrally secured, as by weldingr, to a central axle or hub
16 which is suitably journalèd ~or rotatlon, as on the trough
10. The journaling means may be conventional. Suitable
driving means 18~ such as a variable speed motor 20 and a
drive belt 22 are mounted to provide power to rotate hub 16,
thereby to cause the screw conveyor 12 to rotate. As the
screw conveyor 12 rotates it tends to carry the chicken pieces
C generally longitudinally from one end of the conveyor to
the other.
Lifting means are also provided for lifting the
chicken pieces C out of the marinade As best seen in ~IGURE
- 2, the lifting means there shown comprises a plurality o~ t-
ing vanes 30. Lifting vanes 30 are each positioned between an
adjacent pair of flights 14. Preferably they extend inwardly
from the outer or peripheral edges E of the flights where~
because they and the flight peripheries E are clos~ly ad~a~
cent to the confronting surfaces of the trough (see FI~URE 2)~
neither the flights nor the lifting vanes are likely to cut
into the chicken pieces C as the screw conveyor 12 rotates
In the embodiment illustrated, the vanes are equidistantly
spaced about the periphery of the flights. There i8 at least
one, desirably at least three and, depending upon the size and
dimensions of the conveyor and the speed at which it is to be
run, as many as six or more vanes between each of the adjacent
pairs of flights.
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As vie:led in FIGURE 2, screw conveyor 12 rotates in
a counterclock~lise d~rection. In that case the lifting vanes
30 incline rearwardly from their outer edges 32 ad~acent the
wall of trough 10 ~ith respect to a plane including the edges
32 and the central axis A of hub 16. Stated another way, the
lifting vanes incline rearwardly of the direction o~ rotation
of the screw conveyor 12, desirably at an angle of from about
45 to about 60 degrees. As such, as seen in FIGURE 2, t-he
lifting vanes 30 will tend to scoop up chlcken pieces C as the
vanes approach the very bottom of trough 10 and will tend to
lift pieces C up as the vanes approach the very bottom o~
trough 10 and will tend to lift pieces C up as the vanes move
- upwardly. However, as the lifting vanes continue to move up-
wardly, the chicken pieces C will slide rearwardly and down-
wardly along the vanes 30 and will then drop off the vanes and
downwardly into the marinade solution in the trough. As the ~`
screw conveyor 12 continues to rotate, the chicken pieces C
will be li~ted and dropped back into the marinade over and
over agaln
When the chicken pieces C reach the far end of the
chicken marinatlng assembly 1, it is necessary to remove ~hem
from the trough 10. To that end~ at the end of the lifting
vane section, means are provided ~or effecting the removal of ~i
- the chicken pieces C from the marinating assembly. In the
embodiment illustrated, the Iast t~o pairs of flights mount a~
- - different plurality of vanes, namely discharge vanes 40. Vanes
40 are secured between flights 14 in the same manner as are
vanes 30. Desirably three and preferably as many as six or
more equidistantly spaced discharge vanes are provided between
at least one of the pairs of adjacent flights. Howevers dis-
-charge vanes 40 incline in thP opposite direction, desirably
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553
at an angle of about 45 to abou~ 65 degrees forwardly of a
plane including their outer edges 42 adjacent the ~rough and
the axis A of hub 16. As such, discharge vanes 40 tend to
scoop up the chicken pieces C (see FIGURE 3) and to carry them
upwardly as the screw conveyor rotates un~il the chicken pieces
are carried out of the marinade to an elevation at which they
will freely slide and tumble downwardly. At that elevation,
a discharge chu~e 44 is provided to receive the chicken
pieces C to convey them to a suitable conveyor 46 for the
next processing step. In the embodiment illustrated, conveyor
46 is shown as a container. It may be appreciated, however,
that conveyor 46 could be a continuous conveyor instead.
Lifting vanes 30 are mounted with and secured to
flights 14. In the embodiment illustrated vanes 30 are elon-
gate and flat and several are continuous, extending across
several pairs of adjacent flights. To assemble the vanes to
the flights, the flights are first suitably slotted to ac-
commodate the thickness of the vanes. The vanes 30 are then
forced into the slots across three, four or more flights~ ~
To maintain their securement, the vanes may be welded or ~;
brazed to the flights. Similarly, the flights mounting the
- discharge vanes are first slotted, and then vanes 40 are
fLxed in the slots. Of course, other modes of securing vanes
may be employed such as simply welding or brazing vane plates
at their side edges to the flights.
The vanes may be solid plates. If per~orated, they
-~ would tend to abrade the chicken pieces and would tend to
collect pieces of chicken resulting in equipment which is
difficult to maintain appropriately sanitary. Furthar~ the
inner edges of the vanes are spaced away ~rom th~ hub 16 to
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allow chicken freely to tumble in the marinade.
The lifting vanes may also be of other sh~pes and
configurations. For example, the vanes, as illustrated by
FIG. 4, may be a comb-like member 50 comprising a rod 52
approximately one-half inch diameteI and a plurality of rod-
like inwardly extending fingers 54 three-eights inch in
diameter connected at right angles thereto~ and spaced apart
approximately one-half inch. Fingers 54 extend inwardly and
rearwardly from the peripheral edges of the flights. Such a
member 50 may be ~lelded at its ends between and to adjacent
pairs of ~lights in lieu ofvane plates, and may be angled and
positioned just as the vane plates are~ Comb-like members 50
tend to promote release and sliding of the chicken pieces.
A marinator assembly generally in accordance with
FIGURES 1 to 3 has been constructed and has been used in con-
nection with the processing of chicken pieces. That marinator
assembly utilized a screw conveyor having a 14 inch diameter
The conveyor was about 72 inches long and the ~lights were
spaced 6 inches apart. Six li~ting vanes were provided be ;~
tween each adjacent pair of flights. The lifting vanes were
each angled rearwardly of a plane including their outer edges
and the hub axis at about ~0 degrees. The six discharge vanes
between each of the last t.~wo pairs oP ~lights were angled for-
wardly of a plane including ~heir outer edges oP the hub axis
at about 45 degrees. The lifting vanes and discharge vanes
each extended inwardly o~ the periphery about two inches. The
clearance between the screw conveyor and the semi-cy~indrical
trough bottom was kept as close to about 1/4 inch as was
possible.
Chicken has been processed in the marinator assem-
bly which has been described. First, chicken was cut up into
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nine pieces~ namely into two drumsticks, two thighs, two
wings, two side breasts and one keelbone. These p~eces were
cut from chickens weighing slightly in excess of two pounds
each. In some cases, the chickens had been killed as much
as a ~leek earlier and had been kept packed in ice. In other
cases, the chickens had been freshly kllled and were up to
approximately one day old.
For test purposes, one batch o~ five chickens ap-
proximately one day old (post killing) was cut into nine
pieces each and was introduced into the marinator assembly
just described. m e liquid marinade in the assembly was
maintained at a level of approximately 5 inches above the
very bottom of the trough and the chicken pieces were con-
veyed through the liquid marinade longitudinally from one
end of the conveyor to the other end. The marinade solution
was a ten percent solution of sodium chloride. me level
and salt content were monitored and were supplemented as ~;
necessary during the processing, as through a suitable supply
line 48. The chicken pieces were repeatedly lifted by the
li~ting vanes and Nere carried up out of the liquid marinade
and dropped back into the liquid marinade as the chicken
pieces were conveyed longitudinally ~rom one end of the con-
- veyor to the other in a single run~ The total processing
time was about 15 minutes. At the discharge end of the con-
veyor, the chicken pieces were scooped up by the discharge
` ~ vanes and were discharged into a conveyor as described above~
The weight percent pick-up of marinade was found to be ap-
- proximately 3.8~ in the chicken pieces
Another batch of five chickens about one day old
(post killing) was cut up as described and was similarly
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processed for fi~teen minutes. However, the liquid level in
the trough was maintained at about 3-1/2 inches in depth,
the level of the marinade M illustrated in ~IGURES 2 and 3.
In that case, the total percent pick-up of marinade by weight
as ~ound to be approximately 6.1~. This was substantially
in excess of the 3.8% for chickens carried through the con-
veyor in a marinade maintained at a depth of about 5 inches.
Although the pick-up of marinade when the depth
in the trough was at 5 inches was greater than would have
been obtained by simply immersing the chicken within a mar-
inade for fi~teen minutes, this pair of tests demonstrated
that the more the number of times the chicken pieceæ were
lifted up and out o~ the marinade and tumbled back down into
the marinade, the greater the pick-up of marinade by the
chicken pieces. When the chicken tended to float more and ;~
to remain partially or totally submerged, as it did with the
greater depth of marinade, there was less agitation of the
chicken pieces and less flexing of ~he chicken flesh and
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tissue~ hence less pick-up o~ marinade.
The length-of time after chickens have been killed
is a substantial ~actor in the amount o~ marinade they will
pick up in a marinade processing step. Generally speaking,
immedia~ely a~ter chickens are killed and dressed, they~are
chilled in ice water. During that time they absorb an average
of about 10% water. If they are held in ice for up to a week
or so, they tend~to lose a considerable amount of the absorbed
water as drip out. In other words, the longer the chickens
are held in ice, the more their moisture loss and the greater
the chicken's ability to reabsorb moisture during a subsequent
marination process. Accordingly, chickens whlch are ~reshly
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1~ 553
killed and promptly marinated will tend to pick up much le~s
marinade than ~llll older chickens.
Other tests were run in the marinating apparatus
just described in ~hich five chickens cut into nine pieces
each were marinated. The chickens ~Jere 6 to 7 days old having
been packed in ice. In one test, ~he liquid level was main-
tained at about 3-1/2 inches and the chicken pieces were
carried through the marinator in about 6-3/4 minutes. The
marinade solution was maintained at about 5-1/2% salt. The
total pick-up of marinade ~as about 9%. In yet another test,
the chicken pieces were carried through in two passes of ten
minutes and three minutes, respectively, and the total pick-
up was about 14%. In three other tests, six chickens were
carried through in t~lo passes o* three minutes each and the
total pick-up was about 12, 12.6 and 14.7%, respectlvely, by
weight.
The tests indicate to me that the working o~ the
chicken flesh by repeated forced tumbling by the vanes and
liftings and droppings by the lifting vanes greatly enhances
marinade pick-up as compared to pick-up resulting from the
practice of non-agitating prior art processes. It appears to
me that optimum processing in accordance with this invention
utilizes approximately 40 to 90 liftings out of, and droppings
back into the marinade. Although more or less may be used,
and more or less may be necessary depending upon the amount
of chicken pieces being processed at the same time, the age
- of the chicken, etc., approximately 40 to 90 liftings should
give optimum pick up results within the framework of the
amount of marinade it is desirable to pick up and within the
framework of other of the limitations and restriction~ imposed
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by a continuous chicken processing line on a marinating
step.
Chicken marinated in accordance with the process
of this invention has been subsequently battered, breaded
and frozen~ all in accordance with conventional procedures.
Thereafter the chicken pieces have been conventionally
deep-fat fried. The f~nished fried chicken shows the results
of the moisture pick-up from marination in that the pieces
are quite moist and tender and more so than is the unmar~
inated products. Further, the chicken meat has a better
flavor as a result o~ the salt which is absorbed during the
course o~ the marinating process. Of course, it is also
possible to precook the chicken after marinating, battering
and breading and before freezing.
; Although a screw conveyor has been describsd as the
preferred embodiment ~or the practice of the method of this
invention, it will be apparent that there are other possible
ways of inducing lifting and dropping of the chicken in a `
marinade solution. For example~ conveyors ~hich rise out -~ ;
of marinade solution to carry chicken up~ardly and then allow
it to drop back into the solution, again to be lifted up by
another conveyor or conveyor section3 then to be ~ropped
again, may also be u~ed. ;
Although only a presentl~ pre~erred embodiment of
the apparatus of this invention and a particular mode o~
carrying out the method of this invention have been described
,~ and illustrated, it will be clear to those skilled in the art
~rom the foregoing specification and drawings that modifica-
tions may be made without departing from the spirit and scope
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o~ the invention. Accordingly, the invention disclosed herein
is intended to be limited only as may be required by the claim~.
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