AU710596B2 - Continuous food processing system - Google Patents

Description

3 P: \OPERT H\0753-94. DIV 3/4/9 -1A- CONTINUOUS FOOD PROCESSING SYSTEM 10 BACKGROUND OF THE INVENTION S This invention relates to an extruder for a coated edible strand of food product, and is more particularly directed to an extruder for use in a continuous food processing system whereby an edible plastic food strand of meat or the like is preferably co-extruded with a coated material to be processed into a casing. This coating material may consist of a mixture of gel with a coagulatable protein, and reinforcing means. The extruder is advantageously useful in a method for making an extruded food product which includes the steps of coextruding a hardenable coating substance such as a gel around an elongated edible product and treating the extruded coating with chemical and physical means for coagulation.

Such a method is generally known. These known methods are mainly being used for the co-extrusion of sausage or sausage-like materials. In principle this method involves the P:\OPER\PHH\8075394.DIV -3/4/98 -2extrusion of a cylindrical nucleus of a sausage mix and simultaneously the extrusion around the sausage mix of an outside coating which consists of a gel with a collagen protein. The proteins in the gel are coagulated with the aid of coagulation means.

The term "coagulation" is a term of art in the production of collagen coated sausage material and is not strictly scientific in the sense in which it is used. Coagulation as it is used in this specification refers to the step involving hardening and stabilization of the casing.

This is principally achieved in two ways; firstly by removal of water from the collagen gel, and secondly by cross-linking the collagen fibers.

In the generally known methods the water content of the gel coating is lowered with .oeo the assistance of osmosis by leading the strand of foodstuffs through a concentrated salt bath.

Thereafter an air drying step is used to further enhance the strength of the sausage casing.

After this treatment the mechanical properties of the casing are insufficient to allow for conventional twist linking, clipping, typing, or hanging of the foodstuff, i.e. sausage, strand.

With this usual method it is habitual to crimp the co-extruded strand of foodstuff and cut it into independent elements and these elements are placed in a hot air dryer for the treatment of individual elements (for example drying, smoking etc.) This known method has a number of disadvantages. The first disadvantage is that a sausage is manufactured in which the organoleptical properties are insufficiently equal to sausage which has been manufactured with a natural or artificial casing known in the trade.

A second disadvantage is that the method limits itself to the manufacturing of smoked/cooked P:\OPER\PHH\80753-94, DIV 3/4/98 -3sausage. Dried, semi-dried and fresh sausage cannot be economically manufactured. A third disadvantage is that usual smoke and/or cooking installations cannot be used economically in the further processing. With the known method the meat mix is provided with a collagen coverage while with the traditional methods a casing is used which strongly and flexibly encloses the meat mix entirely during the further processing and shapes the sausage.

Further, a similar method is known from the international patent application W093/12660 whereby it is intended to avoid the aforementioned problems. This method equally includes the steps of coextruding a substantially homogenous layer of collagen gel around an extruded edible product and the chemical coagulation of the extruded collagen gel, though without the step of drying with hot air in order to achieve a coagulated collagen casing around the edible product, which has sufficient strength to allow mechanical separation into individual foodstuff elements which are connected to each other, especially sausages.

Also, with this known method the aforementioned problems and disadvantages have *not been resolved adequately. It has been demonstrated that a thus manufactured casing of collagen gel of co-extruded edible foodstuffs, sausages, has insufficient strength to allow •traditional further processing. Furthermore a consequence of low casing strength is that the shape of the sausage rope is not consistent, principally in certain types of further processing.

For instance, when strands of edible foodstuffs which are thus manufactured are being hung the partly "fluid" meat mix flows down which gives the edible foodstuffs a cone shape. Such a shape for sausages is undesirable. Additionally, due to the mechanical loading of the gel casing which is not strong enough rupture can occur. Also, the production speed with this

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P:\OPER\PHH\80753-94.DIV 3/4/98 -4known method is disadvantageously influenced by the still insufficient strength and shape rigidity of the casing. An additional disadvantage is that, due to the lengthy stay in the coagulation bath, the salt content in the casing and in the meat mix, is high. This results in unwanted organoleptical and physical changes of the sausage mix, such as in taste, consistency and firmness of the meat mix.

While this known method nevertheless has some attributes in spite of the above disadvantages, it is not capable of replicating the mechanical, physical and organoleptical properties of existing conventional sausages.

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C.oe SUMMARY OF THE INVENTION

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-According to the present invention there is provided an extruder for a coated edible ':15 strand of food product, comprising, a housing, an elongated center tube in said housing having first and second ends, an extrusion horn removably mounted in said housing and having inlet and discharge ends, removable closure means on said housing and having an orifice in communication with the discharge end of said horn, said center tube having an inner diameter larger than said extrusion horn so that said horn can be replaced by a second horn of a different diameter by removing said closure means.

The invention also concerns a device for the manufacturing of strands of foodstuffs with a casing which is formed out of a protein, especially of sausage strands, which includes P:\OPER\PHH\80753-94.DIV 3/4/98 means for the coextrusion of a principally homogeneous coating of gel around an edible product, as well as a coagulation bath for the chemical treatment of the extruded gel coating and transportation means for the transportation of the extruded strand of edible foodstuffs which is characterized in a surface dryer installed after the coagulation bath with a purpose of drying the gel casing.

DESCRIPTION OF THE DRAWINGS One embodiment of an extruder in accordance with the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of one embodiment of an extruder; Figure 2 is an exploded view of the extruder of Figure 1 showing interchangeable parts of the extruder to alter the size of the sausage diameter; Figure 3 is a schematic flow diagram of a continuous meat processing system; Figure 3B is a top plan view of one embodiment of apparatus for performing a method for making an extruded food product; Figure 3C is a side elevational view as seen from the bottom of Figure 3B; Figure 3D is an end elevational view as seen from the left hand end of Figure 3C; Figure 3E is an end elevational view as seen from the right hand end of Figure 3D; Figure 3F is an enlarged scale sectional view taken on line 1F-IF of Figure 3B; Figure 4 is a flow diagram of a crimper and sealer used with the method; Figure 5 is a plan view of the pre-crimper of Figure 4 shown at an enlarged scale; Figure 6 is an exploded view of the crimper of Figure 4; P:\OPER\PHH\80753-94.DIV 3/4/98 -6- Figure 7 is a side elevational view of one embodiment of infrared drier used in the method; Figure 8 is an end elevational view of the right hand end of the infrared drier of Figure 7; and Figure 9 is an enlarged detail view of Figure 7 taken on line 9-9 of Figure 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT The principal components of the system shown in Figure 3 are as follows: 1. Meatbatter pump 2. Gel pump 3. Coagulant injection 4. Extruder 5. Salt bath 15 6. Washer 7. Air dryer 8. Portioner 9. Surface dryer q Features of the above components are set forth in the following Table I.

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9.9 9 9.

9 9 9..

99 9 999 99 9 99 9 9 .9.

*9 9 9 .9 9. 9 proessing step~s of the Continuous Caesing Proess.

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Funcion Process-sequence 1 4 I Mest batter 2 Gel8 i Comminuted and semi comminuted 2 Fat, water, protein conteht 3 Other non meat additives 4 Temperature 0 to 18 degrees celslus Kind of collagen 2 Percentage of collagen In gel 3 Percentage of non collagen additives t.l. C.M.C. caramel, etc.

4 PH Temperature 2 to 18 degrees celsius I Kind and concentration of coagulant 2 Percentage of Injection v. collagen 3 PH I To form the sausage rope with strong galling and binding properties while optimizing yield I To coat the meat rope and to be manipulated In a continuous and edible casing I To start crossiing of the collagen 2 To start coagulation of the collagen and proteins of the meatbatter.

3 t Coagulant Injection I To deawell and dehydrate .ne collagen 4 Percentage of salt layer See process step I i 4 lExtruder Revolution per minute f.i. from S0-=0 Temperature 2A to 18 Bdegrees celsius Diameter of the rope from 8mm onwards diameter and coated with a layer of collagen gel of constant thickness 0.5 mm 2 To orientate the fibres of the collagen gel to facililtate the cross linking.

Salt bath \1Knd and percentage 2 Temperature from 5 3 lnTime from 2 up to 60 I I To deaweil and dehydrate the collagen The salt bath may replace the sell 'of salt to 40 degrees C.

seconds layer To allow time for coagulation of the collagen and the proteins of the meat Injection via the coagulant injection or visa versa TABLE I 9 9 9.9 9 99 999 9 999 9 99 9 99 9 *9* 99 9 9 9 999 99 9 9. 9 9 9.9 99 9 9. 999 99 9..

99 9 9 99 9 99 9. 9 99 9 99 9 9 99 9 9.9 9 9 99 99 9 9 I I I The washing may be eliminated eIwashing Water or a less concentrated solution of the salt and/or diluted sugar.

Temperature from 5.40 degrees C.

Time from 2 up to 60 sec.

To reduce the percentage of salt In the collagen layer The washing may be eliminated In the case the seitbath is eliminated 7 IAir dryer Air flow Air temperature 10 up to 40 degrees C.

Time U~l 0.5 to several minutes.

to remove water from the coating To taclilitate the strengthening of the casing by the coagulant Injection, the positioning Is directly after the extruder Po t-Lner sealer j i. Pre- crimper 2. Crimper 3. Sealer I The shape of the meatpusher 2 Rope speed, synchronised with the crimper 3 Crimper speed I Crimp speed 2 Rope speed synchronised with the Procrimper I Kind of polymer non edible: polyamlde. LDDE edible: natural Polymers 2 Temperature 120 -230 degrees C.

3 Time to cool o~f the polymer I To press the meat batter away from the crimp location *1 To form the deffnIte crimp 2 To form the mold to shape the plymer donut I To formn a donut to hold the crimp during fuzrther processing For some sausages It IS advantaguous to use a heatseal Instead of a donut crimp. The heates may be made by means of-ultrasonic heating I I I The surface dryer may replace the air Surface dryer i Radiation Intensity To strengthen the casing by heating the t casing above ahrinktemperature of t collagen gel, up to 80 degrees C.

without coagulating the proteins of thea meatbatter, If desired dryer or vice versa -9 The extruder 4 is best shown in Figs. 1 and 2.

The components of the extruder are as follows: lB. Front plate 2B. Water seal 3B. Outside planer 4B. Bolt Inner planer 6B. Bolt 7B. Flange 8B. Bolt 9B. Dual extruder tube Casing 11B.

12B. Shaft 13B. Gears 14B. Cradle 15B. Tube 16B. (Arrow) 17B.

18B.

19B. Port Fig. 2 shows how members 1B, 3B, 5B and 9B can be removed from extruder 4. They can be replaced with similar components which have a different set Sof discharge orifices 100, 101, 102 and 103 to create strands or ropes of varying diameters.

diameters.

With reference to Fig. 1 casing 10B is stationary, shaft 12B and gears 13B rotate cradle 14B around tube 15B. Member 3B rotates in a direction opposite to member 5B. This causes the 10 fibers in the coating gel to be oriented as the gel moves in the direction of arrow 16B between these two components to be coated on the meat strand exiting from orifice 103 on coextrusion horn 9B. A gel material mixed with a coagulation agent is introduced into horn 9B through port 19B. Meat emulsion or the like is introduced at The collagen dough containing a cellulose ether (gel) and the meat batter are fed to the extruder by a stuffer with a constant volume frequency controlled motor. In the extruder the sausage batter and the collagen gel are extruded simultaneously, so that a continuous rope of sausage is formed with a collagen coating.

The method of extruding comprises feeding under pressure the fluid of collagen fibrils (gel) into a passage way (see arrow 16B) between opposed planer surfaces, rotating said surfaces relative to each other to provide shearing forces to the collagen mass before extrusion. A frequency controlled electro motor provides the rotation of the planer surfaces in opposite senses at 60 to 125 rpm. The two planer surfaces constitute an extrusion die, the gap between them being The lay out crimper and sealer 104 are shown in Figs. 4 and 5. The component parts and function thereof are shown in the following Table II.

11 Table II Crimper and Sealer Nr. Description OC Sausage rope 1C Pendulum 2C Pre-crimper 3C Turning wheel 4C Crimp-sealer Function a.

a To adjust speed (to control the main drive on the crimp-seal machine).

To force the meat batter away from the location of the crimp.

To guide the sausage rope.

To make the crimp by lowering the crimper into the support plate by means of a cam construction.

To lower the dosing unit and to press the nozzle on to the crimper.

To lift the dosing unit, nozzle and crimper after donut is formed.

To set the length of the individual sausages (number of units on the wheel).

To inject an control the amount of polymer into the mould formed by the support plate and the crimper plate. In case of a heat seal, the dosing unit is replaced by a heating element f.i. a ultra sone welder.

Dosing unit 6C Polymer Preparation tank. To mix and heat the polymer.

12 The crimper 105 (Fig. 6) has the following components and functions.

Table III Crimper ID Polymer inlet 2D Connection electricity 3D Dosing valve 4D Roller 5D Spring To dose and control the amount of polymer per donut (crimp) Guided by a circular cam construction to control the vertical movement.

To press the nozzle away from the crimper.

a.

a a a a.

a a 6D Nozzle 7D Crimper To make the crimp and to form a die for the donut.

7D' Slot 8D Support plate 9D Chain V-shaped notch To support the sausage rope and form the contra part of the crimper.

To transport the sausage rope.

To crimp strand 11D V-shaped notch 12D Space A frame (not shown) supports chain 9D to which is secured plate or groove 10D therein.

die 8 which has a V-shaped The frame also supports 13 elements 1D-7D. Crimper (die) 7 has an inverted Vshaped groove 11D therein and dwells in the same plane as die 8. Space 12D permits a strand of product to pass therethrough. Die 7D has notch 7D' therein to receive die 8D. An adhesive or polymer deposits a donut-shaped quantity of adhesive in each crimp in the strand by action of 1D-6D.

The infrared drier is shown in Figs. 7, 8 and 9, and has the following components and functions: Table IV Infrared Drier

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Nr. Description IE Sausage rope 2E Transport chain 3E Chain wheel 4E Power unit Ventilator 6E Air recirculation ducts with regulation valves 7E Air inlet duct Function On support plates To carry the sausage rope through the dryer To pull the chain To provide a controlled speed.

To provide airflow for cooling the IR radiators and the surface of the sausage rope, and to transport the vaporized moisture.

To control air recirculation 8E Air pressure chamber 9E Air exhaust ventilator To divide the air over the functional openings To control the amount of circulation air 14 Support plate liE IR radiator 12E Reflection mirror 13E Opening for cooling IR radiator 14E Opening for cooling sausage rope Restriction plate 16E Air recirculation chamber 17E Frequency control unit 18E Arrows 19E Arrows To provide the energy for vaporizing the moisture in the casing.

To reflect the radiation energy for effective use on the sausage rope.

To control the temperature.

To control the rope temperature and to take away the vaporized moisture.

To provide overpressure in the drying zone.

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p *r 9* p. Pt.

p.

To regulate the frequency of the IR radiation To indicate air flow To indicate infrared radiation.

The arrows 18E indicates air flow, and the arrows 19E indicate infrared radiation.

Figs. 3B 3E show the overall layout of the machine for processing the meat strand. Of particular importance is the serpentine (helix or spiral) tube 106 which receives the coated strand 1.

The strand is conveyed by the brine through tube 106 to a depositing station 107. The tube is coiled horizontally, and a quantity of brine is flushed through tube 106 while the gel coated strand is floated downwardly therethrough to further assist in the curing and coagulation of the coating material.

P:\OPER\PHH\80753-94.DIV 20/4/98 Because the interior of the tube is entirely closed, as compared to a U-shaped trough with an open top, contamination of the interior of the tube is avoided. (See Fig. 3F.) Meat dough is introduced into the system of 108, and collagen dough (gel) is introduced into the system at 109.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

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P:\OPER\AXD\2034631.RSI 22/7/99 -16- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:- 1. An extruder for a coated edible strand of food product, comprising, a housing, an elongated center tube in said housing having first and second ends, an extrusion horn removably mounted in said housing and having inlet and discharge ends, removable closure means on said housing and having an orifice in communication with the discharge end of said horn, said center tube having an inner diameter larger than said extrusion horn so that said horn can be replaced by a second horn of a different diameter by removing said closure means.

2. The extruder of claim 1 wherein said horn has elongated inner and outer concentric compartments for coextruding into a single strand different plastic materials, said extruder having separate parts for receiving said different plastic materials.

3. The extruder of claim 2 wherein said extruder has a passageway existing between surfaces rotating in opposite directions at the outlet end of said outer compartment so that 9 o material in said outer compartment will have to move through said passageway before coating S 15 the exterior surface of the material being discharged from said inner passageway.

S4. An extruder according to claim 1 and substantially as hereinbefore described with S.reference to the drawings.

DATED this 22nd day of JULY, 1999 TOWNSEND ENGINEERING COMPANY by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s) I