Process for producing deboned meat products

Abstract

Material obtained from animals, poultry, or fish and containing edible flesh along with normally inedible relatively hard or tough components, such as bone, gristle, tendons, etc., is fed in ground condition into one end of a perforated conduit that has a conveyor screw therein which progressively decreases in conveying capacity from the feed end of the conduit to an imperforate discharge end thereof. Such inedible components are compacted within the imperforate discharge end of the conduit by an extension of the conveyor screw prior to discharge following build-up and conveyance along the interior surface of the perforate portion of the conduit as a filter mat through which edible flesh is forced toward and through the perforations of the conduit to provide a substantially bonefree edible product. The discharge passage surrounding the extension of the conveyor screw can be varied in size, preferably by a tapered ring that is movable back and forth axially of the conveyor screw extension, and preferably the spacing between conveyor screw and conduit is variable. The forward faces of the conveyor screw flights are preferably concave to provide a forwardly projecting circumferential overhang that tends to keep particles of bone near the axis of the screw, and the conduit wall thickness is unusually thick so as to withstand high pressures. Unusually high production rates can be obtained by feeding finely ground material into the conduit by means of a high pressure pump. The discharged and normally inedible components can be slurried in a digestant liquid and the digested material recovered as a food product by the application of centrifugal force. In instances where some minute particles of bone are discharged with the .[.fleshly.]. .Iadd.fleshy .Iaddend.components, they can be homogenized by subjecting such .[.flesh.]. .Iadd.fleshy .Iaddend.components to an attrition operation.

I claim: 
     
       1. A process for de-boning meat or fish materials containing soft fleshy matter and .[.boney.]. .Iadd.bony .Iaddend.components, comprising the steps of introducing such a material into a perforated conduit that has a feed end and a discharge end and contains a rotary compression screw progressively decreasing in conveying capacity from feed end to discharge end; forming .Iadd.and maintaining .Iaddend.a filter mat of .[.boney.]. .Iadd.bony .Iaddend.components on the inside surface of the perforated conduit by operating said screw to force soft fleshy matter through the perforations of said conduit while retaining .[.boney.]. .Iadd.bony .Iaddend.components against the inner surface of the conduit.Iadd., and by maintaining sufficient clearnce between said screw and said perforated conduit to maintain a thin coating of said bony components between said screw and said conduit.Iaddend.; compacting .[.boney.]. .Iadd.bony .Iaddend.components into a tapered nonperforate section at the discharge end of the conduit; varying the cross-sectional area of said tapered section to govern the pressure exerted on the material within said conduit; and discharging the compacted .[.boney.]. .Iadd.bony .Iaddend.components at said discharge end of the conduit. 
     
     
       2. A process according to claim 1, wherein the filter mat includes .[.boney.]. .Iadd.bony .Iaddend.components collected within the valleys between the flights of the compression screw, said filter mat increasing in thickness and being moved along the said valleys toward the discharge end continuously as the process continues. 
     
     
       3. A process according to claim 1, including the step of comminuting the meat material before introducing it into the perforated conduit. 
     
     
       4. A process according to claim 1, including the additional step of slurrying the discharged compacted .[.boney.]. .Iadd.bony .Iaddend.components in a protein digestant liquid; and separating the resulting slurry into digested material and undigested material by centrifugal force. 
     
     
       5. A process according to claim 1, including the additional step of homogenizing by attrition any .[.boney.]. .Iadd.bony .Iaddend.components that are forced through the filter mat and perforations along with the soft .[.flesy.]. .Iadd.fleshy .Iaddend.material, so as to render said .[.boney.]. .Iadd.bony .Iaddend.components edible.Iadd., said attrition being applied to the soft fleshy material and any bony components that are forced through the filter mat and perforations with the fleshy material.Iaddend.. 
     
     
       6. A de-boning process according to claim 1, wherein the material to be de-boned is introduced into the perforated conduit by pumping. .[. 
     
     
       7.  A process of de-boning meat or fish materials that have been ground together with boney components thereof, comprising forming a filter mat of boney components of such material; passing relatively soft fleshy components of the material through said filter mat, whereby boney materials are filtered therefrom; and recovering the de-boned, relatively soft, edible components separately from the boney components..]. .[.8. A process according to claim 7, wherein the ground material is subjected to pressure against a perforated plate, while passing said material from a location of feed to a location of discharge, whereby the filter mat of boney components is built up against said perforate plate and the fleshy components are passed through said filter mat and through the perforations of said plate; and passing the filter mat along with the material to and through said location of discharge..]. .[.9. A process according to claim 8, wherein the pressure is varied from time to time during the course of the operation, depending upon the character of the material to be de-boned..]. .[.10. A process of producing a meat or fish product from unboned carcass material, comprising grinding said material; de-boning the ground material in accordance with claim 7; slurrying the recovered boney components of said material in a protein digestant liquid; and separating digested material from undigested material by subjecting the resulting slurry to centrifugal force..]. .[.11. A process of producing a meat or fish product, comprising deboning the material as specified in claim 7, the pressure utilized for passing the fleshy components through the filter mat being so great that some of the boney components of the meat material pass through the filter mat and are mixed with the recovered fleshy components; and wherein the recovered fleshy components are thereafter homogenized by attrition to render the contained boney components 
     
     
        edible..]. .Iadd.12.  A process of de-boning meat or fish materials that have been ground together with bony components thereof, comprising forming a filter mat of bony components of such ground material; passing relatively soft fleshy components of the ground material through said filter mat, whereby bony components are filtered therefrom, and recovering the de-boned, relatively soft, fleshy components separately from the bony components; said ground material being subjected to pressure against a perforated plate, while passing said material from a location of feed to a location of discharge, whereby the filter mat of bony components is built up against said perforated plate and the fleshy components are passed through said filter mat and through the perforations of said plate; and passing the filter mat to and through said location of discharge; said perforated plate being in the form of a perforated conduit; said pressure being produced by rotating a rotary compression screw contained within said conduit while maintaining sufficient clearance between said screw and said perforated conduit to maintain a thin coating of said bony components 
     
     
        between said screw and said conduit. .Iaddend. .Iadd.13.  A process according to claim 12, wherein the pressure is varied from time to time during the course of the operation, depending upon the character of the material to be de-boned. .Iaddend. .Iadd.14. A process of producing a meat or fish product from unboned carcass material, comprising grinding said material; de-boning the ground material in accordance with claim 12; slurrying the recovered bony components of said material in a protein digestant liquid, and separating digested material from undigested material by subjecting the resulting slurry to centrifugal force. .Iaddend. .Iadd.15. A process for producing a meat or fish product, comprising deboning the material as specified in claim 12, the pressure utilized for passing the fleshy components through the filter mat being so great that some of the bony components of the meat material pass through the filter mat and are mixed with the recovered fleshy components; and wherein the recovered fleshy components are thereafter homogenized by attrition to render the contained bony components edible. .Iaddend. .Iadd.16. A process of de-boning meat or fish materials that have been ground together with bony components thereof, comprising forming a filter mat of bony components of such ground material; passing relatively soft fleshy components of the ground material through said filter mat, whereby bony components are filtered therefrom, and recovering the de-boned, relatively soft, fleshy components separately from the bony components; said ground material being subjected to pressure against a perforated plate, while passing said material from a location of feed to a location of discharge, whereby the filter mat of bony components is built up against said perforated plate and the fleshy components are passed through said filter mat and through the perforations of said plate; and passing the filter mat to and through said location of discharge; said perforated plate being in the form of a perforated conduit; said pressure being produced by rotating a rotary compression screw contained within said conduit while maintaining sufficient clearance between said screw and said perforated conduit to maintain a thin coating of said bony components between said screw and said conduit, said clearance being maintained on the order to four one-thousandths of an inch. .Iaddend. .Iadd.17. A process for de-boning meat or fish materials containing soft fleshy matter and bony components, comprising the steps of introducing such a material into a perforated conduit that has a feed and a discharge end and contains a rotary compression screw progressively decreasing in conveying capacity from feed end to discharge end; forming and maintaining a filter mat of bony components of the inside surface of the perforated conduit by operating said screw to force soft fleshy matter through the perforations of said conduit while retaining bony components against the inner surface of the conduit, and by maintaining sufficient clearance between said screw and said perforated conduit to maintain a thin coating of said bony components between said screw and said conduit, said clearance being maintained on the order of four one-thousandths of an inch; compacting bony components into a tapered non-perforate section at the discharge end of the conduit; varying the cross-sectional area of said tapered section to govern the pressure exerted on the material within said conduit; and discharging the compacted bony components at said discharge end of the 
     
     
        conduit. .Iaddend. .Iadd.18.  A process for de-boning meat or fish materials containing soft fleshy matter and bony components, comprising the steps of introducing such a material into a perforated conduit that has a feed and a discharge end and contains a rotary compression screw progressively decreasing in conveying capacity from feed end to discharge end; forming and maintaining a filter mat of bony components on the inside surface of the perforated conduit by operating said screw to force soft fleshy matter through the perforations of said conduit while retaining bony components against the inner surface of the conduit, and by maintaining sufficient clearance about four one-thousandths of an inch between said screw and said perforated conduit to maintain a thin coating of said bony components between said screw and said conduit; compacting bony components into a tapered non-perforate section at the discharge end of the conduit; varying the cross sectional area of said tapered section to govern the pressure exerted on the material within said conduit; and discharging the compacted bony components at said discharge end of the 
     
     
        conduit. .Iaddend. .Iadd.19.  A process for de-boning meat or fish materials containing soft fleshy matter and bony components, comprising the steps of grinding the fish or meat material to produce ground material, separately pumping the ground material at a pressure between about 5 to 250 pounds per square inch into the feed end of a perforated conduit that also has a discharge end and contains a rotary compression screw progressively decreasing in conveying capacity from feed end to discharge end; forming and maintaining a filter mat of bony components on the inside surface of the perforated conduit by operating said screw to force soft fleshy matter of said ground material through the perforations of said conduit while retaining bony components of said ground material against the inner surface of the conduit, and by maintaining sufficient clearance between said perforated conduit and the flights of said screw to maintain a thin coating of said bony components between said conduit and said flights of said screw; compacting bony components into a tapered non-perforate section at the discharge end of the conduit; varying the cross-sectional area of said tapered section to govern the pressure exerted on the material within said conduit; and discharging the compacted bony components at said discharge end of the conduit. .Iaddend.