CA1069758A - Method and apparatus for forming a fibrous structure - Google Patents

Abstract

ABSTRACT FOR CANADA

A method and apparatus for forming a proteinaceous mass into a fibrous and layered structure, including imparting a gross fibrous structure to the mass by passing the mass through a belical conveyor and layering the fibrous structure by extruding the same through a slot and into an opening, the compression and extrusion being carried out at elevated temperature to heat set the mass.

Description

~ 97S8 This invention relates to apparatus for forming a proteinaceous mass into a fibrous and ]ayered structure such as proteinaceous material for use as a foodstuff.
Many proposals have been made for forming a proteinaceous mass into a structure which resembles known foodstuffs, for example, meat and fish and essentially these prior proposals seek to achieve a layered and fibrous structure. Natural meat and fish are layered and one of the characteristics of these foodstuffs is that they will readily break apart at the boundaries of the layers. Also, particularly with meat, a close examination reveals a gross fibrous structure. In order to simulate the appearance of meat in a proteinaceous mass which does not inherently possess a gross fibrous structure, for example soya, it has previously been proposed to pass the amorphous mass through a device which includes an internally rotating helical conveyor, for example, a Wenger extruder and then to extrude ; the mass axially in the form of a rope which may then be further processed.
The rotating helical conveyor imparts a certain amount of gross fibrous texture to the amorphous mass.
It is desirable to provide apparatus for forming a proteinaceous mass into a fibrous and layered structure which may be utilised for the production of foodstuffs which gives a much more realistic similarity to the natural foodstuffs than hitherto proposed processes.
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The invention provides apparatus for forming a proteinaceous mass into a fibrous and layered structure, comprising a housing defining an axially - elongated bore, a helical conveyor rotatable in said bore for feeding the mass toward a downstream end of said housing, die structure at the downstream .. end of said housing and including end plate means defining an annular slot communicating with said housing bore and an outer radial boundary for said .: slot having a generally cylindrical internal surface, and plug means for said ~
i end plate means, and said slot having an inner radial boundary defined by a ; generally cylindrical external surface of said plug means only slightly smaller than said internal cylindrical surface, and said plug means being ,, .
;~ spaced axially from said end plate means, both said means having radially : . .
:~?;: extending planar surfaces which face one another to define an annular space ~`i; arranged radially outwardly of said internal and external cylindrical sur-faces, said cylindrical surfaces cooperating to define a restrictive annular extrusion passageway communicating with said annular space and so related to , the cross sectional area thereof that the proteinaceous mass is extruded from said annular slot into a fan shaped pattern in said annular space and folded back upon itself in said space as a result of said radially extending . . .
~ ~ space being oriented perpendicular said cylindrical surfaces of said annular ,: 20 slot.
, : In order to illustrate the invention, several embodiments thereof . will now be described, by way of example only, and with reference to the accompanying drawings, in which:-, .. . .

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FIGURE 1 is a diagrammatic representation of a part of apparatus in accordance with the invention showing an : underlying principle of operation;
FIGURE 2 is a diagrammatic representation of part of further apparatus in accordance with the invention illustrating a further basic concept thereof;
FIGURE 3 is a diagrammatic illustration showing the manner in which the material becomes layered within the apparatus of Figure 2;
FIGURE 4 is a diagrammatic representation of a part of ;~ further apparatus in accordance with the invention;
FIGURES 5 and 6 are diagrammatic perspective views showing extrudate after it has been layered in accordance with -. the methods of the invention;
FIGURE 7 is a diagrammatic view showing a basic layout of apparatus in accordance with the invention;
FIGURE 8 is a cross-sectional view through a die constructed in accordance with one embodiment of the invention; ~-FIGURE 9 is a cross-sectional view through a die in ~: 20 accordance with a further embodiment of the invention;
FIGURE 10 is a cross-sectional view through part of a ;- further die in accordance with another embodiment of the ` invention;
FIGURE 11 is a cross-sectional view through a further die in accordance with yet another embodiment of the invention;
FIGURE 12 is a cross-sectional side elevation through a modification of the apparatus of Figure 8;
FIGURE 13 is an end view of the apparatus of Fi ure 12;

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FIGURE 14 is a cross-sectional elevation through a further die constructed in accordance with the invention;
FIGURE 15 is a cross-sectional view on the line XV-XV of Figure 14;
FIGURE 16 is an end view of the apparatus of Figure 14;
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FIGURE 17 is a lateral cross-sectional view through : a further apparatus constructed in accordance with the ~' invention;
. FIGURE 18 is a cross-sectional view of part of the apparatus of Figure 17;
FIGURE 19 is a cross-sectional view of part of a modification of the apparatus of Figure 18;
FIGURE 20 is a cross-sectional view of part of yet a '' further modification of the apparatus in Figure 18; and : 15 FIGURE 21 is a longitudinal sectional view through a ~, composite die assembly in accordance with the invention.
~ One of the basic concepts of the method of the present '. invention may be explained with reference to Figure 1 of the : : -~: drawings in which a die 1 is provided which defines an elongate ;s~ 20 slot 2 through which the mass is forced in the direction of ;. arrow 3. The precise shape and size of the elongate slot 2 may ~ vary considerably dependent upon the nature of the product to .~
~ be produced, and the starting materials.
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The slot 2 leads to an opening 4 defined by side walls 5 .~ 25 and 6, the side wall 5 being opposite the outlet of slot 2, and . against this wall 5 the extrudate impinges as it emerges from ,.; . .
, the slot 2. This wall 5 may be as depicted in Figure 1, namely E at right angles to the direction of movement of the mass as it ' ',.':
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emerges from slot 2, or may be at some other suitable angle.
The mass in being forced through the slot 2 passes either solely in the direction of arrow 7 if a wall 8 is present, or may pass additionally in the direction of arrow 9 if the wall 8 is omitted. The width of the opening 4 is indicated by dimension A and the width of slot 2 by dimension B in Figure 1.
A further embodiment of basic apparatus in accordance with the invention is indicated diagrammatically in Figure 2 in which the opposed wall 5 in the Figure 1 embodiment is no longer present and the opening 4 forms a direct continuation of the slot 2. It has been found that with this construction the material layers itself as indicated diagrammatically in Figure 3. Whereas in the Figure 1 embodiment, the oppos~d wall 5 brought about a change in the direction of movement of the material and thereby effected layering, in the Figure 2 embodiment it is believed that the back pressure created by the layered extrudate present in the opening 4 brings about the change in - the direction of movement of the material and hence the layering thereof.
In Figure 4 a modification is shown in that the slot 2 -:
enters centrally into the opening 4.
The dimensions A and B may vary considerably dependent upon the starting material and the type of foodstuff to be simulated. It has been found however that the dimension B
may vary between 5 and 20 thousandths of an inch and the dimension A may vary between 10 to 250 thousandths of an inch, but preferably the dimension _ lies within the range 80 to 120 thousandths of an inch.

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The opposed walls 5 and 6 which define the opening 4 within which the extrudate is folded or layered may converge or !~'' ' diverge in the direction of arrows 7 and 9 in Figure 1 or the ~ direction of arrow 7 in Figure 2.
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, 5 The starting materials used have been defatted soya flour, grit or flake (meal) (approximately 50% protein), mixtures of vital wheat gluten/soya flour (O to 30% gluten) and fish protein concentrate/soya flour. Other materials may be suitable including soya concentrate and isolate, tic bean concentrate or flour, mixtures having higher levels of gluten and other animal proteins, comminuted dried meats, wheat starch and other cereal ~ products and also other oil seed proteins. Starting materials .~ may be vegetable or animal or fish protein or single or multi-cell ~ protein or combinations of these materials.
,, Referring now to Figure 7, the dried proteinaceous feed material containing from 30 to 95% protein is fed into a feed hopper lO having a mixing device lOa and into a steam pre-conditioner lOb having a screw feed. From the preconditioner the material is fed into a first section of a helical conveyor 11 which may be a Wenger* extruder. Water is injected at 11_ and the conveyor is rotated by an electric motor llb. The water is metered in by a small variable feed pump or by other accurately ` variable means . " : .
' At the downstream end of the helical conveyor is a die - 25 12 which may have a knife 12a associated therewith for severing lengths of extruded material.
- The feed water may contain additives of, for example, .::
sodium hydroxide up to a concentration of 1.6 grammes per litre (25N~ Under normal operating conditions depending on the * denotes Trademark :
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composition and ambient moisture content of the dry feed material, the moisture of the wetted feed may be from 20 to 40%
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moisture as is basis. The additives may include colourings, flavourings, spices and the like to enhance the acceptability of the product. These may be added prior to or after extrusion.
Different types of helical conveyor may be employed although a Wenger* machine has been found particularly useful.
The machine must be capable of compressing and heating the coagulable proteinaceous material within a chamber. In the Wenger* machine already used, which consists of eight barrels, the first four were cooled while the last four i.e., those nearer the die at the downstream end of the conveyor were steam heated with steam at 70 to 80 psig. The helical conveyor of the Wenger*
X5 may be rotated at any speed between approximately 100 to 900 r.p.m. and the optimum fibrous product is achieved at approximate-ly 600 to 800 r.p.m.
The Wenger* machine thoroughly mixes, compresses and then heat coagulates into a plastic condition the proteinaceous feed material and, during this time, the material is aligned by the rotation of the helical conveyor to give a fibrous material which is then fed into the die 12.
One particular form of die in accordance with the invention is illustrated in Figure 8 in which the helical conveyor 13 rotates within a cylindrical housing 14. At the downstream end of the helical conveyor is an end plate 15 having a ciraular aperture 16. A plug, generallyindicated at 17, has a cylindrical part 18 which projects slightly into the aperture : - , 16 and a further part 19 which has a face 20 which is disposed parallel with a face 21 of the end plate 15.

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The dimensions A and B referred to in describing Figures 1 and 2 are also indicated on Figure 8. The dimension B is the annular slot defined by the plug 18 and the aperture wall 16 and the dimension A is the opening which lies between the faces 20 and 21.
The pressure drop across the die is likely to be in ~.":' :
.', the order of 100 to 500 p.s.i.g. and the temperature of the ~ .
` die and the downstream end of the helical conveyor, about 100 to 180C.
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A modified construction of die is illustrated in - Figure 9 in which like parts to the embodiment of Figure 8 have been given like reference characters. The only difference is that the cylindrical part 18 of the plug 17 projects into an annular recess 22 in the end plate 15 so as to define a stepped opening for the extrudate. The important dimenslons neverthe-less are the dimensions B and A as in the Figure 8 embodiment.
During ~se of the apparatus in accordance with the , ,<
~ invention as described in relation to Figures 7, 8 and 9, it .:i ~- will be appreciated that rotation of the helical conveyor 13 ; 20 compresses the amorphous mass at the same time as the heating .,.
-- means in the form of the heated barrels of the Wenger* raises ;~ the temperature of the mass to produce heat setting. A gross fibrous structure is imparted to the mass as it moves along its helical path towards the die. When the mass reaches a chamber .::
23, as indicated in Figures 8 and 9, a gross fibrous structure *denotes Trademark .;: .
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~;, 10697S8 will have been imparted to the mass, the gross fibres lying generally circumferentially within the mass. As the . pressure then extrudes the mass through the slot into the opening and because the dimension _ of the opening is greater S than the dimension B of the slot, a slight expansion of the extrudate is allowed with substantially no puffing. In the opening 4, into which the extrudate emerges, the mass is layered to produce a structure very generally indicated diagrammatically in Figure 5. This layering is in the nature of folding the material within the opening 4. It will be seen from Figure 5 that the layers generally have an arcuate shape although this may not always accur and may not readily be apparent from an inspection of the extrudate.
Also, the gross fibrous nature of the extrudate has the fibres disposed to conform generally to that same arcuate shape. The individual fibres are indicated very diagrammatically at 24 in Figure 5.
Although theoretically the extrudate has a generally arcuate layered shape as indicated in Figure 5, the shapes extruded will be irregular. However, they will be flat to a thickness substantially equal to the size of opening A and the gross fibres will lie generally parallel with the boundaries ;- 25 between adjacent layers 26 and also generally parallel with the main faces of the extrudate i.e. the face and its equivalent seen in the direction of arrow 27 indicated in Figure 5.

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The product extruded by the method of the invention is extremely fibrous and tough and is partially heat set when it emerges from the opening 4.
The extrudate may then be dried in any suitable drying apparatus 28 (see Figure 7). The dried product may then .~
be reconstituted in boiling water for from 15 to 30 minutes and the reconstituted protein material has a gross structure which is extremely like sliced meat. On close inspection the material is also found to resemble meat in that discrete fibrous threads may be pulled away from the slice. On chewing the material, it is found to be firm and chewy without being too rubbery. The fibrous quality makes it feel quite like meat in the mouth.

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; The product may be boiled in a sauce for two hours ~ or more or canned in a sauce for 90 minutes at 250 F

-; without any apparent deterioration in texture. The slices :
~ of material may also be minced in a standard mincer to give .: ,:
a very realistic mince beef which may be dehydrated.
It is believed that the helical conveyor compresses and heats the starting material to a plastic mass which is . ., -, coagulated by the heat and a fibrous structure imparted by the helical conveyor, these fibres being arranged - circumferentially within the mass. This heat set and plastic mass is then ejected after the last barrel of the , ~~

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Wenger* machine tangentially and travels through the die thr-ough an annular slot and then radially outwardly maintaining a low pressure drop preferably in the order of 200 p.s.i.g. or less. The material is allowed to expand slightly and fold or distort itself as it flows into the opening A. The folding or layering which occurs in the opening is fixed or heat set by - thermal transfer from the end plate which may be stainless steel.
In a modification of the apparatus just described, the die components may be mounted in such a way that gaps of variable dimensions are presented to the material being extruded. For example, a component may be mounted to have limited play so that it will assume an attitude dependent on the pressure of the extrudate. As this pressure fluctuates so the attitude of the component may alter.
. 15 Such a component or more than one such component may be mechanically oscillated by external means such as an electric motor.
One such additional component is illustrated, by way ~, .-: . , of example in Figures 12 and 13 in which it will be seen that a plug 29 inserted into a die plate 30 defines, with back plate 31, .- a radial opening 32, the material being forced in the direction - of arrow 33. A trembler ring 34 is free to oscillate under the ~., ' influence of leaf springs 35 held at their centre by screw 36.
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-~ -12-,, 106g7S8 The effect of this trembler ring will be to restrain the emergence of the extrudate from the gap between the ring and the extruder end plate 31 and thereby create a back pressure which will build up during the folding and layering of the extrudate in the outlet 32. When this pressure builds up to such an extent that it overcomes the restraining influence of springs 35, the extrudate will emerge. Adjustment of the spring pressure will control the amount of tightness of the folds in the extrudate. The trembler ring may be constructed ,:
in such a way that it comprises two or more parts together forming a multi-sectional ring.
In the previously described embodiments, the extrudate emerged from the apparatus in a radial direction and only one die was provided. So as to increase the productive capacity of a radial extrusion die, the embodiments of Figures 10 and 11 have been designed.
~ Referring first to Figure 10, it will be seen that :~ there is provided a helical conveyor 37 within a housing 38.
.- The helical conveyor 37 may be extended by a member 37a which may be smooth or (as shown) provided with helical flights. A
plurality of spaced discs 39, are provided, the gaps 40 between ~ii the discs defining separate outlets for the extrudate and -. the discs being shaped at their inner peripheries with flanges 41 which define, with adjacent discs 39, the slots through which the mass is extruded.
In the embodiment of Figure 11 the downstream end of the helical conveyor 42 may be provided with an extension member 4Za which may be smooth or helical and tapered. The housing 43 is provided with plates 44 which are tapered and, as in the previous embodiment, define with their neighbours, :"

openings 45 through which the extrudate emerges. The inner peripheries of the plates 44 are provided with flange 46 so as to define the slots through which the mass is extruded. The inner peripheries 47 of the plates 44 form an extension of the housing 43 and, together with the outer surface of the tapered end portion of helical conveyor 42a, define a gap 4~ which may narrow at the downstream end of the die. Ihis narrowing of the gap may ensure that the pressure forcing the mass through the slots into the openings 45 is of the same order in all cases.
Whereas in all the previous embodiments above described the constructions contemplated what may be termed radial .:'' ;; extrusion of the mass i.e., the opening is disposed in a plane :
:~ which passes through the rectilinear axis of the helical conveyor, ~-~ it is included within the scope of the present invention to . ;.. ;. .
extrude in other directions which may be termed axial and longitudinal. It may be stated that the opening through which :' . the extrudate emerges in the radial and longitudinal embodiments ~: of the invention are disposed in a plane through the rectilinear :~`
axis of the helical conveyor whereas in the axial embodiment the .i; 20 extrudate emrges into an opening disposed in a plane which is - parallel with a plane within which lies the rectilinear axis of i the helical conveyor. It will be noted that these three directions, namely radial, axial and longitudinal, are intended to refer to ~ three planes which are mutually at right angles to each other.
- 25 However, the invention is not limited to the movement of the extrudate through these planes but the extrudate may move in a . . .
plane which lies at any angle found desirable to the rectilinear axis of the helical conveyor. In all cases, however, the basic :.: :
, ; -14-principals enunciated in connection with Figures 1 and 2 will be adhered to although various angles may be changed, for example, in referring to Figure 1, the wall 8 may not be at right angles to the wall 5 nor need the wall 8 be a straight continuation : 5 of the exit of slot 2.
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. Referring now to Figures 14, 15 and 16, it will be seen ' that in this embodiment, where only the die is illustrated, the . material fed from the helical conveyor in the direction of ; arrow 49 is extruded-through rectilinear slots 50 and emerges ~- 10 into openings 51 disposed in a plane parallel with the plane ::, within which lies the rectilinear axis of the helical conveyor, such axis being indicated at 52. It will be noticed that in . this embodiment two openings 51 are provided one on each side of - the said axis 52. The die includes a block 53 with tapered . .
slots 51. The slots 50 are supplied through openings 54 from chamber 23.
Referring now to Figure 17 which very briefly indicates a construction for longitudinal extrusion it will be seen that two concentric cylinders 55 and 56 are provided, the cylinder 55 being located co-axial with and within the cylinder 56.
The cylinder 55 is provided with inlet slots 57 and the cylinder 56 is provided with openings 58. The openings 58 form the outlets and may be parallel sided or may be converging or .~ diverging as desired. Fither the inner cylinder 55 or the outer ; 25 cylinder 56 will be machined so as to provide the appropriate dimensions of slots leading from the bore of cylinder 55 to the openings 58 conforming to the principle of the invention as enunciated in connection with Figure 1. Such an arrangement -. is illustrated in Figure 18 where the slot through which the :
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In an alternative arrangement illustrated in Figure 20 .~ an inner cylinder 61 is provided with inlets 62 which communicate each with two openings 63 in an outer cylinder 64.
Axial extrusion which is that contemplated with reference to Figures 14, 15 and 16 produces an extrudate as ` illustrated in Figure 5 in which the gross fibres 65 lie parallel . with the main faces of the extrudate and parallel with the ~- boundary layers 66 between adjacent layers 67. This basic type of extrudate differs only from that produced by radial extrusion in that it has a rectangular overall shape whereas with radial extrusion the tendency is for the basic shape to be arcuate as indicated in Figure 4.
With longitudinal extrusion which is that contemplated with reference to Figures 17, 18, 19 and 20, an extrudate is produced which is in accordance with Figure 5.
. In a single piece of apparatus it is conceivable that radial and axial and possibly longitudinal extrusion may be ',~

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carried out and an embodiment employing both radial extrusion , and axial extrusion is indicated in Figure 21. In this Figure it will be seen that radial outlets 69 and axial outlets 70 :
: are provided. A variation of the axial outlet arrangement is ':' :- indicated in that inlets 71 are common to two outlets whereas : ::
.- inlets 72 lead to single outlets.
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Claims (9)

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

1. Apparatus for forming a proteinaceous mass into a fibrous and layered structure, comprising a housing defining an axially elongated bore, a helical conveyor rotatable in said bore for feeding the mass toward a down-stream end of said housing, die structure at the downstream end of said hous-ing and including end plate means defining an annular slot communicating with said housing bore and an outer radial boundary for said slot having a general-ly cylindrical internal surface, and plug means for said end plate means, and said slot having an inner radial boundary defined by a generally cylindrical external surface of said plug means only slightly smaller than said internal cylindrical surface, and said plug means being spaced axially from said end plate means, both said means having radially extending planar surfaces which face one another to define an annular space arranged radially outwardly of said internal and external cylindrical surfaces, said cylindrical surfaces cooperating to define a restrictive annular extrusion passageway communicating with said annular space and so related to the cross sectional area thereof that the proteinaceous mass is extruded from said annular slot into a fan shaped pattern in said annular space and folded back upon itself in said space as a result of said radially extending space being oriented perpendicular said cylindrical surfaces of said annular slot.

2. Apparatus according to claim 1 wherein the ratio of dimensional measure of said annular passageway in the radial direction to the axial width of said annular space lies in the range between 5/10 and 20/250.

3. Apparatus according to claim 1 wherein the ratio of dimensional measure of said annular passageway in the radial direction to the axial width of said annular space lies in the range between 5/80 and 20/120.

4. Apparatus according to claim 1 wherein said generally cylindrical internal surface defining said outer radial boundary for said annular passage-way slot is more particularly defined by a bore in said end plate means, which bore has a constant diameter throughout axial extent of said end plate means and said plug means external cylindrical surface defined by a cylindrical boss part so located axially with respect to said end plate means as to define said annular passageway slot to have an axial length significantly less than the axial extent of said end plate means.

5. Apparatus according to claim 1 wherein said generally cylindrical internal surface defining said outer radial boundary for said annular passage-way slot is more particularly defined by an opening in said end plate means which opening is stepped to define two opening diameters, the larger of said two diameter openings defining said internal cylindrical surface, and said plug means external cylindrical surface defined by a cylindrical boss part so located axially with respect to said larger diameter opening as to define said annular passageway slot to have an axial extent significantly less than the axial extent of said larger diameter opening in said end plate means.

6. Apparatus according to claim 1 wherein said end plate means and said plug means comprise coaxially stacked discs which are spaced from one another to define a plurality of annular spaces as defined, and which discs are annular in shape to define a continuation of said housing bore, said discs having inner peripheries which have axially offset flanged portions defining a plurality of annular passageway slots each of which communicates with one of said annular spaces.

7. Apparatus according to claim 6 wherein said annular discs have progressively smaller inner peripheries so that the continuation of said housing bore formed thereby has a tapered cross sectional area becoming pro-progressively smaller toward the downstream end thereof.

8. Apparatus according to claim 6 wherein each of said end plate means and plug means defining discs has an upstream and a downstream side, and each disc having its axially offset flanged portion at the upstream side with the downstream side of the adjacent disc cooperating therewith to define each annular passageway slot.

9. Apparatus according to claim 8 wherein a circular disc is provided at the downstream end of said stack of discs, said circular disc having a central boss part so located axially with respect to the central opening of the adjacent annular disc to define an annular passageway slot therebetween and an annular space located radially outwardly of said annular passageway slot.