Abstract:
A protein-containing composition is provided which is produced by the steps of: coagulating a protein-containing material; emulsifying the protein-containing material; continuously heating the protein-containing material to a predetermined temperature and maintaining that temperature for a period of time sufficient to sterilize the protein-containing material; continuously cooling the protein-containing material; and aseptically packaging the protein containing material. The resulting product is a high quality, highly palatable, and highly digestible protein source which can be shipped without special accommodations regardless of temperature.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 09/002,323, filed Jan. 2, 1998, now U.S. Pat. No. 6,096,354, issued Aug. 1, 2000 which claims the benefit of Ser. No. 60/034,576 filed Jan. 8, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to (a) a treatment of a meat/protein-containing material before thermal processing and (b) a process for aseptically processing and packaging such material to become shelf stable. More specifically, this invention relates to a process for aseptically processing and packaging meat such as, for example, beef, pork, poultry (for example, chicken, turkey, duck, and goose), lamb, and goat, as well as shellfish and fish protein, and the resulting aseptically-packaged product. 
     Through the years, a wide variety of techniques have been developed for storing food products. Among these techniques are freezing, canning, irradiation, and drying. Also, attempts have been made in the past to store food products using aseptic packaging. 
     Aseptic packaging allows food products to be stored at room temperature for extended periods of time without spoiling or degradation of the product. These benefits are the result of processing the food product to destroy any sources of decay such as thermophilic spores or other pathogens. The product is then placed in protective packaging which has also been made aseptic. This packaging, when sealed, provides a barrier against oxygen and light as well as any later possible invasion by harmful organisms or pathogens. 
     Aseptic packaging techniques have been effectively used to package vegetable matter. However, attempts to package meat and fish protein using aseptic techniques have been commercially unsuccessful. In many cases, the processed protein is unpalatable. Also, previous attempts (to aseptically package meet/protein have not removed fat or water from the product) have resulted in little benefit compared to other food storage techniques. 
     Therefore, a need still exists for a process for aseptically packaging protein which will result in a high quality, commercially useful protein source, which has high digestibility and palatability. 
     SUMMARY OF THE INVENTION 
     The present invention meets that need by providing a process for aseptically packaging protein, particularly meat protein, which is commercially useful, and the product produced thereby. The processed protein can be concentrated by adjusting the percentage of fat and water from the original protein source. The protein is then cut into uniform-sized particles and sterilized. The sterilized protein is aseptically packaged. The resulting product is a high quality, highly palatable, and highly digestible protein source which can be shipped without special accommodations regardless of temperature. Also, when the amount of fat and water in the original meat is changed, the packaged product is an efficient means for shipping large quantities of meat protein long distances. In addition, the product of the present invention is economically beneficial because it is or can be lighter (lower transportation costs) and can take up less storage space (lower storage costs) than the original meat. 
     In accordance with one aspect of the present invention, a protein-containing composition is provided which is produced by the steps of: coagulating a protein-containing material; emulsifying the protein-containing material; heating the protein-containing material to a predetermined temperature and maintaining that temperature for a period of time sufficient to sterilize the protein-containing material; cooling the protein-containing material; and aseptically packaging the protein containing material. Preferably, the steps of the process are carried out on a continuous basis. 
     The protein-containing material may include any coagulable protein such as meat, poultry (for example, chicken, turkey, duck, or goose), pork, beef, lamb, and goat, fish, shellfish, or combinations thereof. Preferably, the protein-containing material is meat, poultry or fish. More preferably, the protein-containing material is meat. The protein-containing material may be, but is not necessarily deboned prior to coagulation. The period of time needed to effect sterilization will depend upon the temperature chosen. Preferably, the material is heated to a temperature of about 250° F. to about 300° F. (about 120° C. to about 150° C.) and held at that temperature for about 1 to about 360 seconds, is sufficient. 
     In accordance with a second aspect of the present invention, a protein-containing composition is provided which is produced by the steps of: coagulating a protein-containing starting material; separating the starting material to produce a protein-containing portion and a fat-containing portion; mixing the protein-containing portion with fat to produce a mixed product; emulsifying the mixed product; heating the mixed product for a sufficient period of time to sterilize the mixed product; cooling the mixed product; and aseptically packaging the mixed product. Preferably, the steps of the process are carried out on a continuous basis. 
     The protein-containing starting material may be any coagulable protein, and preferably is meat. In a preferred embodiment, a stick water portion of broth is produced during the separating step. The broth may be concentrated and mixed back with the protein and fat to form the mixed product. Also, the protein containing material may be deboned prior to coagulating. 
     Preferably, the mixed product is heated to a temperature of at least 250° F. (120° C.). More preferably, the mixed product is heated to a temperature from about 250° F. to about 300° F. (about 120° C. to about 150° C.). 
     Preferably, the mixed product is heated for about 1 second to about 360 seconds. More preferably, the mixed product is heated for about 10 to about 60 seconds, and most preferably heated for about 20 to about 40 seconds. In addition, the fat added in the mixing step is preferably taken from the fat-containing portion from the separating step. 
     In accordance with a third aspect of the present invention, a process for producing a protein-containing composition is provided including the steps of: coagulating a protein-containing starting material; separating the starting material to produce a protein-containing portion and a fat-containing portion; mixing the protein-containing portion with fat to produce a mixed product; emulsifying the mixed product; heating the mixed product for a sufficient period of time to sterilize the mixed product; cooling the mixed product; and aseptically packaging the mixed product. Preferably, the steps of the process are carried out on a continuous basis. 
     Again, the protein-containing starting material may comprise any coagulable protein and preferably is meat. In a preferred embodiment, a stick water portion of broth is produced during the separating step. The broth may be concentrated and added to the protein and fat during the mixing step. Also, the protein containing material is preferably deboned prior to coagulating. 
     Preferably, the mixed product is heated to a temperature of at least 250° F. (120° C.). More preferably, the mixed product is heated to a temperature from about 250° F. to about 300° F. (about 120° C. to about 150° C.). 
     Preferably, the mixed product is heated for from about 1 second to about 360 seconds. More preferably, the mixed product is heated for from about 10 to about 60 seconds, and most preferably the mixed product is heated for from about 20 seconds to about 40 seconds. In addition, the fat added in the mixing step is preferably taken from the fat-containing portion. 
     In yet another embodiment of the invention, a protein-containing composition is provided which is produced by the process of providing a pumpable a protein-containing material, sterilizing said protein-containing material by exposing said protein-containing material to irradiation for a time sufficient to sterilize the protein-containing material, and aseptically packaging the protein-containing material. Preferably, the steps of the process are carried out on a continuous basis. 
     Accordingly, it is a feature of the present invention to provide a process for aseptically packaging protein-containing material which provides a high quality, sterile, highly palatable, highly digestible, easy to transport protein source which can be stored easily and economically. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a flow chart demonstrating a first embodiment of the process of the present invention. 
     FIG. 2 is a flow chart demonstrating a second embodiment of the process of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention produces an improved aseptically packaged protein-containing product which has numerous benefits. First, the product can be transported and stored for prolonged periods of time. The product is relatively temperature insensitive, allowing it to be stored at temperatures ranging from the freezing point of the product to higher temperatures (100° F. or higher) without noticeable quality changes. Therefore, the product of the present invention can be shipped to cold or hot environments without requiring any special handling or storage. 
     In addition, the present invention produces a product with a reduced or increased fat and/or water/broth content. This can result in significantly lower shipping and storage costs. For example, a buyer, seller or producer in any location can aseptically process protein. The protein is processed without the aid of freezing technology. The product can be stored at ambient temperatures for long periods of time and shipped in a non-refrigerated mode. The liquid/broth phase can be concentrated in order to reduce the shipment and/or storage of water. The packaged protein will be of a consistent nature, with protein, fat, and water content being consistent from package to package. The protein can be stored for a year or more. This results in significant savings with regard to manufacturing, storage, transportation and handling costs. 
     The present invention has further benefits. Meat particles processed by the present invention may have amino acid and/or vitamin levels which are very close to the amino acid and vitamin levels in the original meat. This is significant, since many prior art preservation processes destroy large quantities of amino acids and vitamins. For example, traditional in-package sterilization in retorts can greatly reduce the amount of the amino acids and vitamins in canned meat. With the process of the present invention, on the other hand, it is possible to retain a high percentage of the original amino acid/vitamin content of the meat. Amino acids are the “building blocks” of proteins. Therefore, meat particles with high amino acid and vitamin levels are a better nutritional source than meats with lower quantities of amino acids and vitamins. In addition, the processed meat product of the present invention has better palatability and digestibility than meat processed by other techniques. 
     Referring now to FIG. 1, a schematic diagram of an embodiment of the process of the present invention is shown. The process  10  is a continuous process and uses a protein-containing starting material  12 . The starting material  12  contains wet proteins (uncoagulated proteins). Useful starting materials include meat, poultry (for example, chicken, turkey, goose, or duck), pork, beef, lamb, and goat, fish, shellfish, and combinations thereof. Preferably, the starting material is either meat or fish. More preferably, the starting material is meat. Most preferably, the starting material is lamb meat. 
     The starting material  12  is placed in a coagulator  14 . The coagulator  14  coagulates the material to produce a more uniform mass. The coagulator  14  can use heat (direct or indirect) or coagulating agents to effect coagulation. Preferably, a steam injection or indirect coagulator is used. 
     The coagulated material is transferred to an emulsifier  16 . A useful emulsifier  16  is a Wolfking Emulsifier, commercially available from Wolfking Inc. The emulsifier  16  is used to break down the protein-containing particles into substantially uniform-sized pieces. The average diameter of the uniform-sized pieces may vary. Preferably, the average diameter of the uniform-sized pieces is from about 1 mm to about 2 mm. More preferably, the average diameter of the uniform-sized pieces is about 1.6 mm. If the average diameter of the uniform-sized pieces is larger, the temperature and/or hold time of the pieces in the sterilizer will need to be adjusted in order to eliminate all “cool spots.” 
     Alternatively, material from coagulator  14  may be transferred to a surge tank  13  and into a mixer  15 . In mixer  15 , additional ingredients  17  are added such as, for example, vitamins, starches, dry proteins (i.e., proteins which have also been coagulated), minerals, water, and any other organic or inorganic compositions that might be used in a finished product. It is desirable to thoroughly incorporate all such materials in order to achieve a homogeneous mixture. The mixed product is thereafter sent to emulsifier  16 . 
     The substantially uniform-sized pieces from emulsifier  16  are transferred to a surge tank  18 . The surge tank  18  provides a holding area where the uniform-sized pieces can be removed at a steady rate. This allows the process to operate more efficiently and aids in the elimination of unwanted air. Also, the surge tank  18  can optionally be equipped to agitate the product. This aids in maintaining a homogenous mixture. 
     The uniform-sized pieces pass through a pump  20  which propels the pieces into the sterilizer  22 . Pumps which are useful in the present invention include, but are not limited to, positive displacement pumps such as lobe pumps and piston pumps. These pumps move the uniform-sized pieces through the pump cavity and into the sterilizer at a consistent rate. A positive displacement pump which is useful in the present invention is commercially available from APV Crepaco, Inc. However, many other commercially available pumps may be used if the type of pump is matched with the viscosity of the product, volume, and product speed through the system. 
     The uniform-sized pieces are continuously transferred to a sterilizer  22 . The sterilizer  22  can use a variety of techniques to sterilize the uniform-sized pieces. For example, the sterilizer  22  can use heat, irradiation, microwaves, chemical treatment, direct or indirect thermal resistance, radio fretquency, ohmic, or any other system that will adequately sterilize the meat products. Preferably, the sterilizer  22  uses heat. A preferred sterilizer  22  is a scrape surface heat exchanger, commercially available from APV Crepaco, Inc. The scrape surface heat exchanger consists of a cylindrical space, wherein a rotating blade/auger continuously operates, scraping along the walls of the space so as to remove the product from the walls. In the case of the sterilizer  22 , the walls are hot due to being externally heated. 
     Preferably, the uniform-sized pieces are heated in the sterilizer  22  to a temperature which is sufficient to kill pathogens. The uniform sized pieces are heated to a particular temperature and held at or above that temperature for a period of time which is sufficient to kill pathogens. The desired temperature and “hold time” (the amount of time the product is maintained at or above a particular temperature) may vary according to the desired results. 
     Preferably, the uniform-sized pieces are heated to a temperature of at least 250° F. (120° C.). More preferably, the uniform sized pieces are heated to a temperature from about 250° F. to about 300° F. (about 120° C. to about 150° C.). Also, the uniform-sized pieces are preferably held at the desired temperature in a hold tube 23 for at least 1 second. More preferably, the uniform-sized pieces are held at the desired temperature for from about 20 seconds to about 40 seconds. Most preferably, the uniform-sized pieces are heated to a temperature of 275° F. (135° C.) for 20 seconds. 
     The product passes from the sterilizer  22  into the hold tube  23 . The function of the hold tube  23  is to hold the product at or above a specific temperature for a specific amount of time. This provides a means for ensuring that pathogens have been killed. A preferred temperature and hold time is 275° F. (135° C.) for 20 seconds. 
     The product passes from the hold tube  23  into a continuous cooling device  24 , where the product is cooled and the cooking process is stopped. A preferred cooling device is a scrape surface heat exchanger, commercially available from APV Crepaco, Inc. The scrape surface heat exchanger consists of a cylindrical space, wherein a rotating blade/auger continuously operates, scraping along the walls of the space so as to remove the product from the walls. In the case of the cooling device  24 , the walls are cold due to being externally cooled. 
     In another embodiment of the invention, sterilizer  22  uses irradiation rather than heat to sterilize the product. Where irradiation is used, the coagulation step and the emulsification step of the process are optional, as long as the product which is supplied to sterilizer  22  is pumpable. No cooling step is required. 
     The product passes from the cooling device  24  into an aseptic packager  26 . The aseptic packager  26  operates by using steam or hydrogen peroxide in combination with steam to clean and sterilize the spouts. The spouts are sterilized at a temperature high enough to kill pathogens. The product passes through the sterilized spouts into containers. The type of container used may vary from a 2500 lb. high barrier material bag or container to a single serving cup. Preferably, a large high barrier material bag or container or foil barrier bag is used. The aseptic packager  26  then injects the sterilized protein-containing product into the bags, resulting in a packaged product  28 . 
     Referring now to FIG. 2, a schematic diagram of a second embodiment of the process of the present invention is shown. The process  70  is also preferably continuous and uses a protein-containing starting material such as meat  72 . Preferably, the meat is lamb meat. 
     Optionally, the meat  72  may be placed in a deboner  74  to remove the bones from the material. A useful deboner is a BEEHIVE™ deboner, commercially available from Beehive Machinery, Inc. The deboner  74  operates by pushing the soft material against a screen, allowing the soft material through the screen while hard materials such as bones are separated. The resulting material has the consistency of ground meat. 
     The deboned material is transported to a surge tank  76 . Surge tank  76  provides a holding area where the deboned material can be removed at a steady rate. This allows the process to operate more efficiently. 
     The deboned material is transferred from the surge tank  76  to a coagulator  78 . The coagulator  78  coagulates the material to produce a more uniform mass, The coagulator  78  can use heat (direct or indirect) or coagulating agents to effect coagulation. Preferably, a steam injection or indirect coagulator is used. The material should be heated to a temperature for from about 160° F. to about 230° F. and held at that temperature for from about 10 to about 300 seconds. Various combinations of temperature and time may be used as long as the material is fully coagulated. The coagulated material is then transferred to a surge tank  80 . 
     The coagulated material is transferred from the surge tank  80  to a separator  82 . A device using centrifugal force or a press may be used to separate the liquid from the solid phase of the coagulated material. The separator  82  separates the coagulated material into at least two, and preferably three portions, a fat-containing portion  84 , a protein-containing portion  86 , and a stick water/broth containing layer  88 . “Stick water” is a liquid phase that contains protein and may also contain fat. It may also be called broth and may contain water soluble fat and protein. The separation of the material into three phases allows for the recombination of these materials at a desired quantity and rate. A useful separator is a Three Phase Decanter, commercially available from Wesifalia Separator, Inc. A useful press is a Dupps press, commercially available from the Dupps Company. The fat portion  84  contains a majority of the fat from the meat  72 . The protein portion  86  contains a majority of the protein from the meat  72 . The stick water portion  88  contains a significant part of the water from the meat  72 , as well as some soluble fat and protein. 
     The fat portion  84  is transferred to a holding tank  100 . The separation of the fat portion  84  allows for the control of precise proportions of protein, fat and moisture in the final product. Therefore, the portion of the fat  84  which is transferred to the batch mixer  98  is dependent upon the fat content of the starting material and the desired fat content in the final product. The remainder of the fat portion  84  is removed from the holding tank  100  and used for other purposes. From about 0 to about 100 percent of the fat portion  84 , and typically 100 percent, is transferred to the batch mixer  98 . 
     The stick water portion  88  is transferred to the surge tank  90 . From the surge tank  90 , the stick water portion  88  passes into an evaporator  92 . The evaporator  92  uses heat and/or a vacuum to evaporate clarified water from the stick water portion  88 . The clarified water is stored in the clarified water tank  94 . The clarified water contains essences from the starting material. Such essences may be added back into this or other mixed products as an odorant, attractant, or palatizing agent, either with or without further concentration. The remaining liquid is a concentrated broth containing a higher percentage of solids, which passes into a concentrated stick water holding tank  96 . The concentration of solids depends upon the type of equipment and the desired concentration level. For example, the stick water layer  88  may contain 2 to 6 percent solids, while the concentrated broth may contain 25 percent or more solids. Preferred evaporators are plate, falling film, and rising film evaporators, or any other concentrator/evaporator that will raise the solids content of the liquid. Preferably, a plate evaporator is used. A plate evaporator operates by passing liquid over a heated surface. 
     The protein portion  86  is sent to a holding tank (not shown) and thereafter is combined with the broth and part of the fat portion  84  in a batch mixer  98 . The batch mixer  98  can combine the protein portion  86 , the fat portion  84  and the concentrated stick water portion  96  to produce a variety of ingredient percentages. Ingredient percentages will be consistent for a given run. Percentages of ingredients can be varied widely depending upon the desired final product. Preferably, the mixed product contains from about 10 to about 40 percent protein, from about 30 to about 60 percent water, from about 10 to about 60 percent fat, and from about 0 to about 5 percent ash. 
     While the portions are recombined in this embodiment, it may not be necessary to recombine the protein portion  86  with either the fat portion  84  or the stick water portion  88  so long as the protein portion flows properly. The protein portion  86  can be processed alone. Alternatively, outside sources of fat and/or water may be combined with the protein portion using the batch mixer  98 . Also, additional ingredients  101  may be combined with the protein, fat, and broth portions using the batch mixer  98 . Additional ingredients  101  include vitamins, starches, dry proteins (these are proteins which have been coagulated), minerals, water, or any other organic or inorganic compositions that might be used in a finished product. It is desirable to thoroughly incorporate all such materials in the batch mixer  98  in order to achieve a homogeneous mixture. 
     The mixed product is transferred from the mixer  98  to a surge tank  102  and then to an emulsifier  104 . A useful emulsifier  104  is a Wolfking Emulsifier, commercially available from Wolfking Inc. The emulsifier  104  is used to break down the mixed product into substantially uniform-sized pieces. The average diameter of the uniform-sized pieces may vary. Preferably, the average diameter of the uniform-sized pieces is from about 1 mm to about 2 mm. More preferably, the average diameter of the uniform-sized pieces is about 1.6 mm. If the average diameter of the uniform-sized pieces is larger, the temperature and/or hold time of the pieces in the sterilizer and hold tube will need to be adjusted. 
     The substantially uniform-sized pieces are transferred to a surge tank  106 . The surge tank  106  provides a holding area where the uniform-sized pieces can be removed at a steady rate. This allows the process to operate more efficiently. The uniform-sized pieces pass through a pump  108  which propels the pieces into the sterilizer  110 . A pump which is useful in the present invention uses positive displacement to move the uniform-sized pieces through the pump and into the sterilizer at a very consistent rate without adding air to the product. A pump using positive displacement is commercially available from APV Crepaco, Inc. However, many other commercially available pumps may be used if their settings are matched with the viscosity of the product volume and product speed through the system. 
     The uniform-sized pieces are transferred to a sterilizer  110 . The sterilizer  110  can use a variety of techniques to sterilize the uniform-sized pieces. For example, the sterilizer  110  can use heat, irradiation, microwaves, chemical treatment, direct or indirect thermal resistance, radio frequency, ohmic, or any other system which will adequately sterilize the product. Preferably, the sterilizer  110  uses heat. A preferred sterilizer  110  is a scrape surface heat exchanger, commercially available from APV Crepaco, Inc. The scrape surface heat exchanger consists of a cylindrical space, wherein a rotating blade/auger continuously operates, scraping along the walls of the space so as to remove the product from the walls. In the case of the sterilizer  110 , the walls are hot due to being externally heated. 
     Preferably, the uniform-sized pieces are heated in the sterilizer  110  to a temperature which is sufficient to kill pathogens. The uniform sized pieces are heated to a particular temperature and held at or above that temperature for a period of time which is sufficient to kill pathogens. The desired temperature and “hold time” (the amount of time the product is maintained at or above a particular temperature) may vary according to the desired results. 
     Preferably, the uniform-sized pieces are heated to a temperature of at least 250° F. (120° C.). More preferably, the uniform sized pieces are heated to a temperature from about 250° F. to about 300° F. (120° C. to about 150° C.) . Also, the uniform-sized pieces are preferably held at the desired temperature in a hold tube  112  for at least 1 second. More preferably, the uniform-sized pieces are held at the desired temperature for from about 20 seconds to about 40 seconds. Most preferably, the uniform-sized pieces are heated to a temperature of 275° F. (135° C.) for 20 seconds. 
     The product passes continuously from the sterilizer  110  into the hold tube  112 . The function of the hold tube  112  is to hold the product at or above a specific temperature for a specific amount of time. This provides a means for ensuring that pathogens have been killed. A preferred temperature and hold time is 275° F. (135° C.) for 20 seconds. 
     The product is transferred from the hold tube  112  to the continuous cooling device  114 , where the product is cooled. A preferred cooling device is a scrape surface heat exchanger as previously described or any other mechanism which cools aseptically. In the case of the cooling device  114 , the walls are cold due to being externally cooled. 
     Again, in an alternative embodiment, sterilizer  110  utilizes irradiation for a time sufficient to sterilize the product. Where irradiation is used, the coagulation and emulsification steps of the process are optional, as long as the product is pumpable. No cooling step is required. 
     The product continuously passes from the cooling device  114  into an aseptic packager  116 . The aseptic packager  116  operates by using steam or hydrogen peroxide in combination with steam to clean and sterilize the spouts. The spouts are sterilized at a temperature high enough to kill pathogens. The product passes through the sterilized spouts into containers. The type of container used may vary from a 2500 lb. high barrier material bag or container to a single serving cup, with a large, high barrier material bag or foil barrier bag being preferred. The aseptic packager  116  then injects the sterilized protein-containing product into the bags, resulting in a packaged product  118 . 
     The aseptically packaged product of the present invention can be shipped and then processed at its final destination, and fat and/or water may be reintroduced. All of the original protein source may be aseptically packaged. Preferably, about 40-70 percent of the original product is present in the packaged product. The other products (the additional fat and stick water) may be aseptically packaged separately. 
     The packaged product may be stored at a variety of temperatures ranging from the freezing point of the product to higher temperatures (100° F. and higher) without noticeable quality changes. However, ambient temperatures for storage are preferred. Note that the freezing point of the product is considered a limitation only due to concerns regarding the breakdown of package integrity. The concern is that water in the product will freeze and expand, breaking the container. Therefore, if the packaging material can withstand such expansion of the product, the product can be stored at very low temperatures, well below the freezing point of the product. 
     While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims.