Abstract:
An apparatus and method is disclosed for forming an emulsion or batter into shaped food products without the use of a casing. The apparatus includes a hollow stuffing tube connected to a source of suitable proteinaceous emulsion, and a molding tube mounted about the stuffing tube, the molding tube having an open end and a closed end. A supply of emulsion is conveyed under pressure into the stuffing tube to form a continuous length of shaped emulsion. Then, the shaped emulsion is directed into the molding tube, where the pressure of the emulsion bears against the closed end of the molding tube and causes the molding tube to move relative the stuffing tube. A treating fluid is directed to the interior surface of the molding tube, such that the interior surface is continuously wetted and evenly coated by the treating fluid, thereby forming a proteinaceous skin about the shaped emulsion.

Description:
BACKGROUND  
         [0001]    Sausages and other formed meat products such as bologna, frankfurters, vienna sausages, and the like are typically made by extruding a proteinaceous meat emulsion or batter into an artificial casing of the desired size and shape and then cooking the batter within the casing. Thereafter, the casing is peeled from the meat product and discarded. Once the casing has been removed, the shaped meat product can be cut into predetermined lengths, placed in suitable containers, and then heated to cook and sterilize the product.  
           [0002]    In order to form and process sausages and the like without the need to use casings with their additional costs and problem of disposing of the used casings, various devices and methods for making casingless sausages have been proposed. Among these is the apparatus disclosed in U.S. Pat. Nos. 5,056,425 and 5,118,519 to Mally. The Mally patents disclose apparatus which ejects partially shaped products onto a conveyor assembly. According to the patents, batter is pumped into a molding tube, and a treating assembly is formed as a continuation of the molding tube. The treating assembly functions to introduce treating fluid, typically a food grade acid solution, which causes a proteinaceous skin to form about the batter. A piston or ram mechanism then causes the batter with proteinaceous skin to be deposited onto a conveyor belt. The conveyor belt then continues into a cooking apparatus. Once cooked, the product is canned.  
           [0003]    U.S. Pat. No. 3,885,053 to Townsend also discloses a process of forming a skin on an extruded meat emulsion by applying an acid to the surface of the emulsion as the extrusion proceeds. The Townsend patent relies on the use of sintered metal to apply the acid.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention relates to apparatus and methods for forming a proteinaceous emulsion or batter into shaped food products such as sausages without the use of a casing. A supply of suitable proteinaceous emulsion is provided and such emulsion is conveyed under pressure into an elongated hollow stuffing tube to form a continuous length of shaped emulsion. Thereafter the shaped emulsion is directed into a molding tube which is slideably mounted about the stuffing tube. As the emulsion enters the molding tube, the pressure of the emulsion causes the molding tube to move away from the stuffing tube.  
           [0005]    A treating fluid, such as a diluted food grade acid, is directed to the interior surface of the molding tube at about the point where the emulsion first enters the molding tube. The treating fluid is directed to the interior of the molding tube in such a manner that the interior of the molding tube is continuously wetted by the treating fluid as the molding tube moves relative to the stuffing tube. This ensures that the entire surface of the shaped emulsion is contacted by the treating fluid thereby forming a proteinaceous skin about the shaped emulsion.  
           [0006]    After the molding tube is filled with the emulsion, it is separated from the stuffing tube, subjected to a heat treatment, and a length of formed sausage is removed from the molding tube and subjected to further processing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective view of the apparatus used to make casingless food products according to the present invention.  
         [0008]    [0008]FIG. 2 is a partial sectional view of the combined stuffing tube and molding tube showing the molding tube slideably mounted about the stuffing tube.  
         [0009]    [0009]FIG. 3 is a partial sectional view of the molding tube showing the emulsion with a proteinaceous skin.  
         [0010]    [0010]FIG. 4 is a perspective view showing the molding tube in a hot water bath.  
         [0011]    [0011]FIG. 5 is a perspective view showing a length of partially coagulated emulsion being removed from the molding tube and cut into suitable lengths for further processing.  
         [0012]    [0012]FIG. 6 is a perspective view of a further embodiment of the invention showing the inner and outer tube.  
         [0013]    [0013]FIG. 7 is a sectional view of the embodiment shown in FIG. 6 showing the inner tube positioned in the outer tube and manifold.  
         [0014]    [0014]FIG. 8 is a perspective view of the treating fluid supply tank.  
         [0015]    [0015]FIG. 9 is a perspective view of the embodiment shown in FIGS. 6 and 7 showing the inner tube and outer tube.  
         [0016]    [0016]FIG. 10 is a partially broken away view of the embodiment shown in FIGS. 6, 7, and  9  showing the inner tube positioned within the outer tube.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    The following is a description of the forms of the invention which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.  
         [0018]    As shown in FIGS. 1 and 2, the numeral  10  designates generally the apparatus employed to make casingless food products according to the present invention and includes an elongated tubular shaped stuffing tube  20 , a molding tube  70  which closely surrounds stuffing tube  20  and is slideably mounted about the stuffing tube, an emulsion source  50 , and a treating fluid source  60 .  
         [0019]    As shown best in FIG. 2, elongated stuffing tube  20  includes concentrically mounted tubes  22  and  26  with inner tube  22  having bore  24 , which bore extends the length of tube  22  and with tube  22  being operably connected to emulsion source  50 . An outer tube  26  substantially surrounds the length of inner tube  22  and is operably connected to treating fluid source  60 . An annular passage  28  is formed between outer tube  26  and inner tube  22  and serves to conduct the treating fluid to a point of contact with the emulsion  78 . As used herein, the term treating fluid means an appropriate diluted food grade acid such as acetic acid, citric acid, maleic acid, or phosphoric acid. The concentration of said acid can range from about 2% to about 80%. A 20% concentration of acetic acid works well. Annular passage  28  terminates at seal  32 . A series of apertures  34  are formed about the circumference of tube  26  adjacent to seal  32 , and these apertures allow the release of treating fluid from passage  28 . It is preferred that apertures  34  be set within annular recess  35  to help prevent clogging of the apertures by emulsion  78 . Instead of apertures, a continuous opening about the circumference of the tube  26  may be employed. The exterior surface of inner tube  22  is also provided with channel  42  with O-ring  44  positioned within the channel. O-ring  44  prevents treating fluid exiting from apertures  34  from leaking out from the area between the exterior surface of tube  26  and the interior wall of molding tube  70 .  
         [0020]    At one end, the stuffing tube  20 , which conveys the emulsion, terminates with frustoconically shaped orifice  36  which has an enlarged opening  38  for passage of emulsion  78  into the molding tube  70 . At its opposite end, inner tube  22  is connected to pipe  48  by means of elbow shaped connector  46 . Pipe  48  is then connected to emulsion source  50 . A rotary metering pump  52  is connected between emulsion source  50  and pipe  48  so that emulsion is drawn from emulsion source  50  and pumped into bore  24  of inner tube  22 . A suitable rotary metering-pump is available from Townsend Engineering Company as a “Frank-a-Matic” metering pump.  
         [0021]    As further shown in FIG. 2, annular passage  28  is operably connected to treating fluid source  60  in the following manner. The lower end of stuffing tube  20  is provided with angled extension  54  having passage  56  which communicates with annular passage  28 . Pipe  58  conveys treating fluid from treating fluid source  60  to annular passage  28 . Pipe  58  is provided with threaded fitting  62  for engagement with the threads of passage  56  of extension  54 . A rotary pump  64  is mounted between the treating fluid source  60  and the stuffing tube  20  and is operably connected to pipe  58  to provide treating fluid under pressure to annular passage  28 . It is preferred that rotary pump  64  be a non-pulsating pump. A suitable rotary pump is available from Cole-Parmer Instrument Company and includes a “Micropump” pump head #P-0700225 and pump drive P-7522500.  
         [0022]    Thus far the stuffing tube  20  and its components have been described which function to form a continuous length of shaped emulsion or batter and to supply a treating fluid, such as food grade acetic acid, for application to the surface of the formed emulsion. The actual application of the treating fluid to the surface of the formed emulsion takes place in the molding tube. As shown in FIGS. 1 and 2, molding tube  70  is slideably mounted about stuffing tube  20  and is sized so that the interior wall of molding tube  70  is in slideable contact with the exterior wall of tube  20 , more specifically, the exterior wall of outer tube  26 . As shown, molding tube  70  is about the same length as stuffing tube  20  although its length may be longer or shorter than that of the stuffing tube. As shown, molding tube  70  is provided with threaded ends  72  and one end has a threaded cap  74  which seals off an end of the molding tube.  
         [0023]    In use, molding tube  70  is placed over stuffing tube  20 . Cap  74  is then engaged with the end of molding tube  70  nearest orifice  36  of inner tube  22  so that one end of molding tube  70  is sealed. Pumps  52  and  64  are started. Due to the action of pump  52 , emulsion flows under pressure from emulsion source  50 , through pipe  48  and into the interior of tube  22 , that is bore  24 . Simultaneously, treating fluid is pumped from fluid source  60  by means of pump  64  through pipe  58  and into annular passage  28 . The treating fluid exits apertures  34  and evenly coats the interior wall of molding tube  70 .  
         [0024]    Due to the continued action of emulsion pump  52 , emulsion travels through bore  24  and exits bore  24  at orifice  36 . Similarly, treating fluid travels through annular passage  28  to apertures  34  where it exits the passage  28 . The pressurized emulsion  78  exits orifice  36  and bears against the sealed end of molding tube  70 . Thus, molding tube  70  is pushed away from orifice  36 . As molding tube  70  moves away from orifice  36 , treating fluid exits from apertures  34  and coats the inside of molding tube  70 . It is then absorbed onto the surface of emulsion  78 . It is important that the fluid flow from apertures  34  be continuous so as to evenly coat the inside of molding tube  70 . When the emulsion exiting orifice  36  comes into contact with the treating fluid coating the inside of molding tube  70 , the proteins in contact with the acid coagulate causing a proteinaceous skin to develop about the surface of the emulsion as it is extruded from orifice  36 . The proteinaceous skin provides the aesthetic appearance that consumers like and, in addition, makes the emulsion easier to handle for processing. In addition, the acid treating fluid reacts with nitrates in the emulsion and imparts a pink color to the product which is desired by consumers. Importantly, the treating fluid also lubricates the inside of molding tube  70  so that the emulsion may be easily removed from molding tube  70  after partial cooking.  
         [0025]    A further embodiment of the apparatus for forming casingless food products such as sausages is shown in FIGS. 6 through 10, wherein the numeral  110  designates generally the apparatus employed to make casingless food products according to the present invention. The apparatus includes an elongated tubular shaped stuffing tube  120 , which includes an inner tube  122  and outer tube  126 , a molding tube  70  (see FIG. 1) which closely surrounds stuffing tube  120  and is slideably mounted about the stuffing tube, an emulsion source (not shown), and a treating fluid supply tank  160 .  
         [0026]    As shown best in FIGS. 9 and 10, elongated stuffing tube  120  includes concentrically mounted inner tube  122  and outer tube  126  with inner tube  122  having bore  124 , which bore extends the length of tube  122  and with tube  122  being operably connected to an emulsion source.  
         [0027]    As shown best in FIGS. 6 and 7, at one end, outer tube  126  is welded to the exterior of manifold  150 . Annular passage  128  is formed between outer tube  126  and inner tube  122  and is operably connected to treating fluid source  160  in the following manner. The lower end of outer tube  126  is provided with angled extension  154  having passage  156  which communicates with annular passage  128 . An adjustable flow control valve  163  is secured to extension  154 . Control valve  163  is in turn connected to pipe  158 , which conveys treating fluid from treating fluid source  160 . Thus, treating fluid is conveyed by pipe  158  from treating supply tank  160 , through control valve  163  and extension  154  and into annular passage  128 .  
         [0028]    Inner tube  122  is concentrically positioned within outer tube  126  and slidable therein. Inner tube  122  is positioned in outer tube  126  and is connected to manifold  150 . Opening  129  of inner tube  122  is aligned with passage  153  of manifold  150 . Emulsion enters manifold  150  by means of a supply line (not shown) from an emulsion source and the supply line is connected to passage  153 . The emulsion then travels through opening  129  and into bore  124  of inner tube  122 .  
         [0029]    The end of inner tube  122  which passes into and through manifold  150  is provided with internal threads  122 A which mate with external threads  151  of hand screw  152 . By turning threads  151  of hand screw  152  into and out of engagement with threads  122 A of inner tube  122 , the vertical position of inner tube  122  within outer tube  126  can be selectively adjusted.  
         [0030]    As shown best in FIGS. 9 and 10, the end of inner tube  122  opposite manifold  150  is provided with collar  121 , which is of larger diameter than inner tube  122 . The exterior of tube  122 , has a tapered area  121 A which extends between collar  121  and tube  122 . The interior of collar  121  also is provided with tapered area  121 B which extends between the interior of collar  121  and bore  124  of inner tube  122 .  
         [0031]    As previously noted, outer tube  126  substantially surrounds the length of inner tube  122  with annular passage  128  formed there between. Annular passage  128  is operably connected to a treating fluid supply tank  160  and serves to conduct the treating fluid to a point of contact with the emulsion. Annular passage  128  terminates at end  127  of outer tube  126 . End  127  is provided with both interior tapered area  127 A and exterior tapered area  127 B. As shown in FIG. 10, a circumferential gap or opening  134  is formed at the junction where tapered area  121 A of inner tube  122  abuts tapered area  127 A of outer tube  126 . Treating fluid from passage  128  is released from gap  134 . Importantly, the width of gap  134  is adjusted by selectively changing the vertical position of inner tube  122  within outer tube  126 . By turning threads  151  of hand screw  152  into and out of engagement with threads  122 A of inner tube  122 , the vertical position of inner tube  122  within outer tube  126  is selectively set so that the width of gap  134  is controlled. As gap  134  is widened, more treating fluid is released from passage  128 .  
         [0032]    The exterior surface of outer tube  126  is also provided with channel  142  with O-ring  144  positioned within the channel. O-ring  144  prevents treating fluid exiting from gap  134  from leaking out from the area between the exterior surface of tube  126  and the interior wall of molding tube  70 .  
         [0033]    Treating fluid supply tank  160  is shown in FIG. 8. Tank  160  is provided with removable cap  161  for the introduction of treating fluid into the tank. Air under pressure is supplied to tank  160  via air line  162 , which is provided with air shut off valve  167 . Tank  160  is also provided with relief valve  164 . It is preferred that air be introduced into tank  160  at a pressure of about 80 to 85 pounds per square inch. Relief valve  164  should be set so that if pressure exceeds the pre-set pressure, the excess pressure is released through the valve  164 . Tank  160  is also provided with fluid shut off valve  165  for shutting off the supply of pressurized treating fluid into pipe  158 . It is preferred that tank  160  be made of stainless steel, and a suitable tank is available from Alloy Products Corporation.  
         [0034]    The application of the treating fluid to the surface of the formed emulsion takes place in the molding tube. As with the embodiment previously described, molding tube  70  is slideably mounted about stuffing tube  120  and is sized so that the interior wall of molding tube  70  is in slideable contact with the exterior wall of tube  120 , more specifically, the exterior wall of outer tube  126 .  
         [0035]    Molding tube  70  is positioned over stuffing tube  120  with the end of molding tube  70  nearest collar  121  of inner tube  122  being sealed. Emulsion under pressure from the emulsion source passes through passage  153  of manifold  150 , through opening  129 , and into the interior of tube  122 , that is bore  124 . Simultaneously, treating fluid under pressure from tank  160  enters annular passage  128 . The treating fluid exits through gap  134  and evenly coats the interior wall of molding tube  70 .  
         [0036]    Emulsion under pressure travels through bore  124  and exits at collar  121 . Similarly, treating fluid travels through annular passage  128  to gap  34  where it exits annular passage  128 . The pressurized emulsion exits bore  124  at collar  121  and bears against the sealed end of molding tube  70 , thus causing molding tube  70  to be pushed away from collar  121 . As molding tube  70  moves away from collar  121 , treating fluid exits from gap  134  and coats the inside of molding tube  70 . It is then absorbed onto the surface of the emulsion.  
         [0037]    As shown in FIG. 3, when molding tube  70  has been filled with treated emulsion, tube  70  is removed from stuffing tube  20  or stuffing tube  120 . The open end of molding tube  70  is then sealed with another threaded cap  74  so that the entire tube is sealed.  
         [0038]    As shown in FIG. 4, when both ends of molding tube  70  have been sealed with caps  74 , the molding tube is subject to heat treatment by placing it in a water bath  76  to cook the emulsion. A temperature of from about 180° F. to about 210° F. works well. It is preferred that the temperature of the water in bath  76  be about 180° F. and that molding tube  70  remain in the water for about 2 minutes to further coagulate the proteins in the emulsion. Molding tube  70  is then removed from water bath  76  and placed in a second water bath (not shown) for cooling the partially coagulated emulsion. It is preferred that the water in the second water bath have a temperature of about 55° F.  
         [0039]    Other heated fluids such as hot air may also be used in the heat treating aspect of the formation of the sausages. The heat treatment serves to coagulate the protein throughout substantially all of the emulsion.  
         [0040]    Once molding tube  70  and emulsion have been sufficiently cooled, tube  70  is removed from the water bath and both of caps  74  are removed. As shown in FIG. 5, a length of partially coagulated emulsion  82  can then be slid out of molding tube  70  and onto a cutting surface. Rotary mounted cutters  86  then slice the length of partially coagulated emulsion  82  into smaller lengths  84  for placement into cans. The smaller lengths  84  are then canned and sterilized.