Note: Descriptions are shown in the official language in which they were submitted.
2~
1 FOOD PRODUCT
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..
18
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.
29
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.
21
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.
27
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.
12
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.
23
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.
18
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.
16
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.
19
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.
13
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).
31
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.
28
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
11
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).
22
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.
29
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.
33
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.
24
_amPle 2.
26
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.
11
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.
18
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.
27
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.
11
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.
21
22 Exam~les 6-10.
23
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.
33
