CA2064709A1 - Food product - Google Patents

Abstract

ABSTRACT

FOOD PRODUCT

A sheet of proteinaceous product is produced by comminuting heat-coagulable meat without substantially heat-coagulating the meat, and applying a layer of the comminuted (but still heat-coagulable) meat to a heated roller, or other suitable surface. The heat coagulates the meat to form a sheet, which can then be removed for example by a doctor blade. Under appropriate conditions, a ripple effect may be formed. The sheet can be folded and subsequently processed, for example into chunks for use in petfood.

Description

2~

3 This invention relates to proteinaceous food products, 4 which may be suitable for use either in human food or in an animal food such as pet~ood.

7 Various proresses for preparing meat analogues from 8 generally vegetable protein sources have been proposed 9 in the past. US-A-2682466, US-A-2802737, US-A-2830902 and US-A-3142571 axe examples of proposals for 11 preparing meat analogues from such protein sources as 12 soy bean isolate and peanut protein isolate. Another 13 example is GB-A-1418778, which discloses the 14 preparation of a meat analogue starting from a dry mix of proteins, starches and/or gums. A11 of the above 16 processes may be regarded a examples of meat analogue 17 generatior..

19 Roll-rafining is a process which is known Por producing proteinaceous food products and comprises passing 21 material betwe~n a pair of oppositely rotating rollers.
22 GB-A-1432278 describes the roll-re~ining la-rgely of 23 non-meat proteins, although one of its examples, 2~ ins~ead of starting with soya protein or casein, begins with "ground meat", soya protein, water and other 26 additives and another of its examples begins with 27 "ground meat", water, casein rennet and other 28 additives.

For the food-stuff manufacturer, who has a choice 31 between either meat protein or non-meat protPin 32 sources, it would be preferable ln many instances to 33 use meat prateins so that an all-meat product can be 2 2~ n9 1 prepared. Roll~refining has sucessfully been applied 2 to raw proteins of vegetable origin, and it has been 3 desirable to apply the same technology to meat 4 proteins.

6 GB-A-2198623 discloses the roll-re~ining of fish 7 protein. However, when attempts were made to apply the 8 roll-refining technology to proteins from the higher 9 animals (mammals and birds), the process has been found to be unworkable since it has generally been found that 11 it~ is not possible to form a sheet of proteinaceous 12 product ~rom raw mammalian or avian meat unless 13 substantial amounts of additives, such as binding 14 materials are mixed with the meat prior to the process for forming the proteinaceous sheet. Where untreated 16 mammalian or avian meat with no additives has been 17 used, a cohesive sheet is not formed. Sheet products 1~ are particularly use~ul as they may be folded or 19 otherwise used to give a layered structure resembling meat, particularly when cut into chunks.

22 In EP-A-0328349, published on 16th ~ugust 1989, it is 23 disclosed that where at least part of the mammalian or 24 avian meat is functionally inert, a cohesive sheet may be`formed by roll-refining without the use of additives 26 such as binders being necessary.

28 This was a surprising finding since mammalian and/or 29 avian meat which is entirely ~unctionally active was 3U not ~ound to be capable o~ forming a cohesive sheet, by 31 roll-re~ining, and so it was highly unexpected that 32 functionally inert mammalian and/or aYian meat would 33 form a cohesive sheet. Further, it is also surprising 3 ~ 7~9 1 that the presence of functionally inert proteins 2 appeared to be essential to achieve any fo~m of sheet 3 product. In the method described in EP-A-0328349, a 4 multiplicity of rollers must be used in the roll-refining process, and at least part of the protein 6 must be functionally inert, as defined therein.
8 It would be advantageous to provide a process in which 9 heat-coagulable meat can be formed into a sheet, particularly i f this can be achieved without employing 11 a multiplicity of rollers.

13 According to the present invention there is provided a 14 process for producing a sheet of proteinaceous product, the process comprising comminuting a material 16 comprising heat-coagulable meat without substantially 17 heat-coagulating the meat, and applying a layer 13 comprislng the comminuted meat which has not 19 substantially lost its heat coagulability to a surface on which the layer is at least partially 21 heat-coagulated to form a sheet, and removing the sheet 22 from the surface.

24 The heat-coagulable meat is prePerably presant in an amount of from 5% to 100% by weight of the material to 26 be comminuted. Examples of sources of heat coagulable 27 meat include any heat-coagulable protein derivable from 28 an animal (eg mammalian) carcass, such as musc}e meat, 29 heart, liver, kidney and fish meat. However it is pre~erred that the heat-coagulable meat does not 31 comprise fish meat, since fish meat is relatively 32 easily heat coagulated and so requires more strict 33 contxols on the conditions o~ comminutio~ so as not to 7.~ 9 substantially heat-coagulate the meat during 2 comminution.

4 The material to be comminuted may comprise an edible 5 substance other than heat-coagulable meat.

6 Alternatively or additionally such edible substances 7 may be added to the comminuted material following 8 comminution. Suitable edible substances generally 9 include animal meat or meat by-products such as skin, 10 bone, feather, connective tissue, treated animal 11 carcass products such as pork skin and greaves, and 12 powdered meat meal. The edible substance may comprise 13 "functionally inert proteinl' as defined and exemplified 14 in EP A-0328349. Other suitable edible substances may 15 be of a plant source, such as gluten, soya, cereals ~

16 pulses, gums and may include vitamins, minerals, oils 17 and/or fats.

19 Although it has been found that while heat-coagulable 20 meats which have not been sufficiently comminuted do 21 not form a sheet when a layer thereof is applied to a 22 surface and ak least partially heat-coagulated, it has 23 now surprisingly been found that when the 24 heat-coagulated meat has been co~uninuted suffiaiently, 25 it can form a sheet under such conditions. Without 2 6 wishing to be bound by theory, this is thought to be 27 due to the size reduction causing increased release and 28 availability o~ proteins which are heat-coagulable 29 after comminution.
31 The maximum average particle thickness may yenerally be 32 3mm, while the particles may be as small as is 33 conveniently practical, but will usually be larger than , 2~ s~g 1 10 micrometres. There are believed to be no 2 theoretical limitations on how small the partiales may 3 be, and generally, the smaller the particle size, the 4 better results will be obtained. However, depending on the apparatus used there are likely to be practical 6 limitations on the size of the co~minuted particles~
7 Typically, the average particle size will be in the 8 range from 40 micrometres to lmm.
. g Any suitable comminution technique may be used provided 11 that it avoids substantially heat-coagulating the meat;
12 that is to say, ~or example, localised temperature 13 within the material being comminuted should be kept 14 below a temperature at which the heat-coagulable meat 1~ would be at least partially heat-coagulated.

17 The conditions under which comminution takes place 18 should be such that the heat-coagulable meat is not 19 substantially heat-coagula~ed during comminution. For example, ik should be ensured that the temperature of 21 the material during ths co~minution step does not rise 22 so that the heat-coagulable meat is coagulated. The 23 temperature of the material during comminution is 24 suitably not moxe than 10C and not less than 20C and will usually be in the range from 5C to -5C t~pically 26 from 0C to 4C. Maintenance of a relatively low 27 temperature may be achieved by comminuting a chilled or 28 frozen material and by using an apparatus~which 29 generates low shear during comminution. Suitable apparatus includes size reduction techniques which are 31 well known in the art such as CO~ITROL ~Trade ~ark) or 32 a Bowl Chop device, for example a HOBART BOWL C~OPPER
33 (Trade ~ark). A low temperature of the material may be 6 2~ n9 1 maintainad with ice, and/or low temperature li~uids 2 such as carbon dioxide liquid may be added to the 3 material before and/or during comminutionO

After comminution the meat may be applied as a layer to 6 a suitable forming surface. The layer may be applied 7 to the surface by any convenient means. The layer may 8 be dropped onto the surface by gravity, for example 9 from a reservoir such as a hopper. Pressure may be applied to the material to aid its application to the 11 surface. Where pressure is applied it should be 12 ensured that the pressure does not in~rease the 13 temperature sufficiently to cause heat-coagulation of 14 the heat-coagulable meat prior to its contact with the surface. Pressure may be applied, for example, by the 16 use o~ a "fish-tail spreader", enabling the provision 17 of a long, thin feed, or by the use of a ball-point 18 type of device.

The surface to which the layer comprising the 21 comminuted meat is applied may be a solid continuous 22 surface. In some embodiments the surfaae will comprise 23 a smooth flat sheet. The surface may be a moving ~4 surface, for example, a rotating roller, or alternatively may be stationary. Alternatively the 26 surface may be discontinuous, and may, for example, 27 comprise a mesh, orl a multiplicity o~ beads, such as 28 hot glass beads or marbles.
2~
An important characteristic of the present invention is 31 that heat-coagulation to form a sheet largely takes 32 place on the surface, while there is little or no 33 substantial heat-coagulation of the heat-coagulable 2~?~ 9 1 meat prior to application to the surface~ By contrast, 2 in GB-A-2198623 the material has substantially lost its 3 heat-coagulability prior to formation of a sheet on the 4 surface. In EP-A-0328349 at least part of the protein must be functionally inert and is not heat-coagulable.
7 In order to heat-coagulate the layer on the surface to 8 ~orm a sheet, heat must be applied to the layer while g on the surface. Pre~erably, the layer is heat-coagulated by the usa of a heated surface and/or 11 the direct application of external heat to the layer, 12 for example, by convection or radiation. The layer 13 should be suf~iciently thin so that it coagulates on 14 the surface.
16 The temperature of the layer when the layer is heat-17 coagulated is preferably in the range ~rom 60 to 80C
18 where substantially non-fish heat-coagulable meat is 19 used, and in the range 40 to 50C where substantially heat-coagulable fish meat is used. The temperature of 21 the surface i5 æuch as is necessary to achieve these 22 temperature~, and is dependent on the thickness o~ the 23 layer and the speed with which the layer is applied to 24 and removed rom the surface.
26 The layer generally has a thickness in the range from 27 0.2mm to 2cm, preferably from o.5 to 2mm. The layer on 28 the surface may in some embodiments be smoothed on the 29 surface. For example where the surface is ~a main roller, one or more ancilliary smoothing rollers~may be 31 positioned around the circum~erence ts smooth the layer 32 on the roller. The ancilliary smoothing rollers 33 optionally may exert shear on the layer on the roller.

2~ ,n9 1 The sheet of food product has ,at least one dimension 2 and preferably two dimensions of at least 3cm, 3 preferably at least lOcm, most preferably at least 4 lOOcm or lm or more in length.

6 The protein content of the sheet is generally in the 7 range from 5% to 50% by weight, more typically in the 8 range from lo to 40% by weight. The balance will 9 largely comprise water. The water content is generally in the range from 30 to 95% by weight, and preferably 11 from 50 to 90% by weight, more preferably 75 to 85% by 12 weight.

14 The sheet may be removed from the surface by any suitable means, including manually guiding the sheet 16 off the surface, using a sheet handling device, 17 scraping the sheet of~ the surface, or dropping the 18 sheet from the surface. Especially where it is desired 19 to form a rippled sheet, the sheet may be removed by the use of a doctor blade in relative motion to the 21 surface. The effectiveness of ripple formation is 22 dependent upon the angle of the doctor blade to the 23 surface at the point of contact, the apparent direction 24 of approach of the layer to the blade and the type of doctor blade used. For example, where a roller is used 26 as the surface~ the layer should approach the blade in 27 a downward direction and the angle of the blade should 28 be between the angle 90 and 40 from the vertical 29 section of the roller. In order to improve ripple formation it is preferable to use a blade with a 31 sharpened point rather than a flattened end. A
32 suitable pressure for the doctor blade will readily be 33 ascertainable by one skilled in the art; it may range 2 ~ .~
1 .................... 5 7~3 1 from a very light pressure (such as 5 kg/m2). As an 2 example, the doctor blade may bear against a roller at 3 a pressure in the order of 250 psi t1.8 x 105 kg/m2).
4 Collecting the food product by means of a doctor blade results in the food product being collected in a 6 sheet-like form.
8 It will be appreciated that the sheet may be allowed to 9 form a relatively large area, or may be chopped, cut, torn or otherwise reduced in size (laterally and/or 11 longitudinally) as it is removed from the surface. The 12 sheet may be subjected to further processing, for 13 example: (a) folding the sheet to form a layered 14 structure; (b) baking the sheet to form a biscuit-like structure; and/or (c) setting the sheet in a gel-like 16 matrix~ OEten the sheet will be allowed to fold onto 17 itself, and this may form the requisite layered 18 structure described under (a) above. The weight of the 19 sheet itself may be sufficient to give suEficient density to the layered structure, but pressure may 21 alternatively be applied to increase the density of the 22 structure. The pressure will generally be in the order 23 of from 0.1 ~o 2 atmospheres (l x 104 to 2.1 x 105 24 kg/m2), for example in the order of 1 atmosphere (1 x 105 kg/m2). All pressures are gauged pressures. The 26 addition of such pressure may be conveniently effected 27 in a mould. The layered structure may be cut into 28 chunks, simulating the appearance of cubes o~ meat.
29 The chunks may subsequently be cooked, for example in a can (and/or in gravy).

32 Alternatively or additionally, the sheet may be removed 33 from the surface and baked to form a biscuit-like _,.. . . , _ _ C1~ I;/r, f~ T O
2~ p ~Ji . ~ . . . . ..... _ .

~:6~7~9 1 structure as described under (~) above~ Baking will 2 generally be carried out above 100C, for example at a 3 temperature of from 100 to 250C. Baking temperatures 4 of 150 to 200C are typical. Baking may be conveniently be done in an oven, which in a continuous 6 process will be located downstream of the surface.

8 Further in the alternative or additionally, the sheet 9 may be set in a gel-like matrix. Before so setting, the sheet can be shredded or dried, depending on the 11 desired effect to be achieved. The food product may be 12 set in a gel-like matrix by causing it to come into 13 contact with (for example by immersion) a fluid capable 14 of forming a gel-like matrix. The fluid may consist of known gelable meat mixtures known in the art, such as 16 blood, comminuted meats and offal and fat mixtures as 17 used in sausages and meat puddings. Such systems are 18 believed to depend on the denaturation and gelation of 19 proteins to effect texturisation through the addition of salts and~or the application of heat. The fluid may 21 also contain, either as well as or instead of the above 22 ingredients, plant gums or mucilages, which will in 23 general contribute to the texture of the medium. Where 24 desirable for reasons of product aesthetics, the fluid can have a portion or all of the animal pxotein 26 replaced by vegetable proteins such as 90y or wheat 27 gluten.

29 Typically, therefor~, the composition of the fluid can therefore comprise from 0.1 to 30%, eg. 5 to 15%
31 protein, with the residue being water, fats flavours, 32 clours, gums and/or thickeners, and cofactors for each 33 or any of them. Protein may alternatively be absent, ~r~ n9 1 in which case a different gelling agent, such as a 2 carbohydrate gelling agent, is used. The sheet or a 3 portion thereof can be added, typically at a level of 4 from 5 to 10%, to the fluid, after which the combined system is used to set, for example by inducing yelation 6 and/or thickening. The precise method of setting is 7 not important and will depend on the functional 8 properties of such gelling and/or thickening agents as 9 are present. For example, proteinacPous agents such as albumins or caseins may be heat set, while plant gums 11 such as alginates and pectates may be gelled with 12 calcium or other (generally divalent) metal salts, or 13 hot caxrageenan solutions merely left to gel on 14 cooling. The effect of setting the product initially obtained as a sheet will be to provide striations and 16 fracture points within a comparatively amorphous gel.
17 It is then possible, once the gel has set, to break it 18 in irregular pieces or chunks, and a meat like 19 appearance will be evident in many cases. The pieces or chunks may subse~uently be cooked, for example in a 21 can (and/or in gravy).

23 Depending on their moisture content (which can 24 subsequently be increased or decreased as desired), products produced by a process in accordance with the 26 invention can either be used on their own or as 27 incorporated ingredients in human or animal foodstuffs, 28 and in particular in petfoods.

It will be appreciated that the further processing of 31 the sheet may include all permutations and combinations 32 of each and any of variants (a), (b) and (cj.

2~;i L~ ~9 l The invention also extends to cover products of a 2 process or processes as described above.

4 The invention will now be further described with reference to the following examples.

7 Exam~e l.

9 Commercially available poultry mechanically recovexed meats (~RM) was prepared to give a particle size of lmm ll in a COMITRO~ processor. The raw meats were obtained 12 frozen and the temperature of them kept below 2C
13 during the size reduction process. The material was 14 applied evenly by pouring on to the surface of a revolving roller so that an even film thickness of lmm 16 was obtained. The roller surface was heated and the 17 residence time o~ the film on the drum was adjusted to 18 give a material temperature of 70C. A doctor blade l9 was applied to the film at a pressure of l.6 x 105Kgm 2 and a corrugated sheet of material removed. This sheet 21 is able to be used as such, shredded or formed into 22 chunks. The material may be used in heat processed 23 canned foods for human or petfood applications.

_amPle 2.

27 The procedure of Example l was followed except that 93%
28 MRM was size reduced to give an average particle size 29 of lmm at 4C using a HOBART BOWL CHOPPER cooled with solid C02. 2% salt was added with mixing to the bowl.
31 The mixture was spread evenly over the roller and 32 processed as in Example l. The addition of salt was 33 found to give improved texture and appearance to the 13 X~6~7~9 1 product. Salt was found to enhance functional material 2 release and a sheet of material was formed.
4 Example 3.

6 A mixture of turkey necks (49~), beef intestines (49%), 7 and 2% dry bovine blood was size reduced to 40 microns 8 using a COMITROL whilst maintaining the temperatures of 9 the material below 5C. Tha material was then handled as in Example 1, and a sheet of material was formed.

12 Example 3 showed that less functional material that is, 13 the beef intestines (as defined by the Jellotron test 14 in European application number EP-A-0328349 can be made to work provided (a) functionality is retained and (b) 16 sufficient size reduction occurs to release functional 17 material.

19 Comparative Example 3a.
21 The procedure of Example 3 was followed except that the 22 particle size was 5mm. No homogeneous sheet formation 23 on the heated surface and hence no texturisation was 24 achieved.
26 Com~arative Example 3b.

2~ The procedure of Example 3 was followed except that the 29 particle size reduction was to lmm by passing the material through a plate mill under high friction, high 31 shear conditions with a temperature rise to 80C during 32 grinding. No homogeneous sheet formation on the heated 33 surface and hence no texturisation was achieved.

. .. __ _ f~ O F
2~ 9~1 ~........ ,............. 1 . ...... 1 14 ~ 9 1 ExamPle 4.

3 The procedure of Example 1 was followed except that 4 whitefish flesh such as mechanically recovered cod was used instead of poultry. The residence time; before 6 removing the film by a doctor blade was contralled to 7 give a material temperature o~ 50C. The material was 8 formed as a sheet, as in Exampleæ 1 to 3.
. 9 Exam~le 5.

12 The procedure of Example 1 was followed except that a 13 mixture comprising mechanically recovered beef ~90%) 14 and meat meal (10%) was used instead of poultry. Both materials were reduced to a particle size of less than 16 lmm using a HOBART BOWL CHOPPER and chilling with solid 17 CO2 and intimately mixed at 10C. A sheet was 18 sucessfully ormed. This demonstrates that a 19 proportion of non-Eunctional material can be incorporated.

22 Exam~les 6-10.

24 The procedure of Example 5 was followed except that a minority component of gluten (15~), soya (20%), 26 pea.flour (30%), feathermeal (10~) and powdered dried 27 skin (10%) was used, respectively to replace the meat 28 meal entirely and where the addition level is above 10%
29 to substitute for additional fractions of the MRM. In all cases suitable sheets were obtained which could be 31 processed in aesthetically pleasing forms in petfood 32 products.

Claims (12)

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

1. A process for producing a sheet of proteinaceous product, the process comprising comminuting a material comprising heat-coagulable meat without substantially heat-coagulating the meat, and applying a layer comprising the comminuted meat which has not substantially lost its heat coagulability to a surface on which the layer is at least partially heat-coagulated to form a sheet, and removing the sheet from the surface.

2. A process as claimed in claim 1, wherein heat-coagulable meat is derived from muscle meat, heart, liver and/or kidney.

3. A process as claimed in claim 1 or 2, wherein the material to be comminuted comprises an edible substance in addition to the heat-coagulable meat.

4. A process as claimed in claim 1, 2 or 3, wherein the temperature of the material during comminution is not more than 10°C and not less than -20°C.

5. A process as claimed in any one of claims 1 to 4, wherein after comminution the meat is applied under pressure as a layer to a forming surface.

6. A process as claimed in claim 5, wherein the surface to which the layer comprising the comminuted meat is applied is the surface of a rotating roller.

7. A process as claimed in claim 5 or 6, wherein the surface is heated so as to heat-coagulate the layer on the surface to form a sheet.

8. A process as claimed in claim 7, wherein the temperature of the layer when the layer is heat-coagulated is in the range from 60 to 80°C where substantially non-fish heat-coagulable meat is to be coagulated, and in the range 40 to 50°C where substantially heat-coagulable fish meat is to be coagulated.

9. A process as claimed in any one of claims 5 to 8, comprising smoothing the layer on the surface.

10. A process as claimed in any one of claims 1 to 9, wherein the sheet is removed from the surface by the use of a doctor blade in relative motion to the surface.

11. A process as claimed in any one of claims 1 to 10, wherein the sheet so formed is further processed by:
(a) folding the sheet to form a layered structure; (b) baking the sheet to form a biscuit-like structure;
and/or (c) setting the sheet in a gel-like matrix.

12. A product of a process as claimed in any one of claims 1 to 11.