CA1066553A - Continuous method and apparatus for marinating poultry - Google Patents

Abstract

Abstract of the Invention A continuous method for enhancing the pick-up of mar-inade by poultry, such as chicken. Cut chicken pieces are introduced into a continuous conveyor assembly in which marinade liquid is maintained at a predetermined level. The chicken pieces are conveyed longitudinally of the conveyor and are repeatedly lifted up out of the marinade and are dropped back into the marinade, optimally between 40 and 90 times. A con-tinuous marinating apparatus is disclosed having an elongate screw conveyor for carrying chicken pieces longitudinally of a vessel in which the conveyor is positioned. The screw con-veyor has a plurality of vanes between adjacent pairs of screw conveyor flights for lifting the chicken pieces and for allow-ing the chicken pieces to drop back into the liquid in the trough. Discharge vanes at the end of the screw conveyor scoop up the chicken pieces and convey them upwardly to a discharge station for discharge outwardly of the trough.

Description

,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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1~6~S53 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 _~ j 3 :
:. . .. . ,.. , ~65S3 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 -4_ ~ i 5~3 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.

~ S 53 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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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 _9_ : .

',:, ~,. . ~ ' ' ,, ',. ' ' ~ 5~ 3 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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106~5S3 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 . ~ , 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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''. . ~', ' , 65~i3 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 :: .
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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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of marinating poultry pieces, com-prising cutting poultry into poultry pieces, introducing said poultry pieces into an elongate continuous conveyor assembly, maintaining liquid marinade in said conveyor assembly and continuously 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 poultry 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.

2. The method of claim 1 in which said poultry is chicken.

3. The method of claim 2 in which said chicken pieces are lifted and dropped from forty to ninety times.

4. The method of claim 3 in which said conveyor assembly comprises a screw conveyor in a trough for contain-ing said marinade, and said screw conveyor defines a plural-ity of flights for conveying said chicken pieces longitudi-nally through said marinade.

5. The method of claim 4 in which said screw conveyor mounts rearwardly inclined lifting vanes for lifting said chicken pieces out of the marinade and for dropping said chicken pieces back into said marinade.

6. A continuous marinator assembly comprising an elongate trough and a continuous screw conveyor in said trough, said screw conveyor having a central hub and a plurality of flights 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 res-pect 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 conveyor for lifting poultry pieces upwardly, said discharge vanes extending inwardly from the peri-phery of at least one pair of adjacent flights and inclining forwardly in a direction opposite from the direction at which the lifting vanes are inclined, a discharge chute at one end of said trough adjacent the end of the screw con-veyor mounting the discharge vanes for receiving poultry lifted by the dis-charge 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.

7. A marinator assembly of claim 6 in which said lifting vanes are at least three in number between each pair of flights and are equi-distantly spaced about the periphery of the flights.

8. A marinator assembly of claim 6 in which said discharge vanes extend forwardly at an angle of from about 45° to about 65° from a plane including the outer edges of the discharge vanes and the axis of said hub.

9. A marinator assembly of claim 6 in which said flights are slotted, and in which said lifting vanes are flat plates seated and re-tained in the flight slots.

10. A marinator assembly of claim 6 in which said lifting +
vanes comprise comb-like members having their fingers extending inwardly and rearwardly from the peripheral edges of said flights.

11. A marinator assembly of claim 7 in which said lifting vanes comprise comb-like members having their fingers extending inwardly and rearwardly from the peripheral edges of said flights.