Note: Descriptions are shown in the official language in which they were submitted.
CA 02041314 2000-04-04
66850-30
This invention relates to the manufacture of vital
wheat gluten with substantially no objectionable flavor or
aroma and thus suitable for use in various food products,
which may also contain meat, poultry or dairy analogues.
Vital wheat gluten, often simply called wheat
gluten, is a vegetable protein product extracted by aqueous
processes from wheat or wheat flour. Various gluten
extraction processes are described for example in U.S.
patents 2,797,212 (Miley et al.), 3,463,770 (Fellers),
3,493,384 (Fellers), 3,498,965 (Fellers), 3,501,451
(Fellers), 3,574,180 (Johnston et al.), 4,486,342 (Bateson
et al.) and 4,494,530 (Jansma et al.).
Commercially available vital wheat gluten has the
following typical composition (by weight):
Moisture 5 to 8%
Protein, %N*5.7, dry basis 75 to 81%
Free Lipids. dry basis 0.3 to 2.5%
Total lipids, by acid hydrolysis 5 to 9%
Ash, dry basis 0.5 to 1.5%
The bread-baking properties of wheat flour are
mainly due to the unique visco-elastic properties of its
gluten protein. In order to preserve these properties, the
processing conditions, especially temperature, are critical.
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' CA 02041314 2000-04-04
66850-30
Vital wheat gluten can be spray dried as in U.S.
patent 2,891,045 (Montgomery et al.), or drum dried as in
U.S. patent 2,567,980 (Tuomy et al.), but most commercially
produced vital wheat glutens are flash dried, for example in
a process such as that described in U.S. patent 2,559,551
(Weber).
Flash drying produces a dry powdered gluten
suitable for typical gluten uses such as in bread-baking
where the gluten is added to strengthen low protein flours
or flour doughs which contain added fibre, protein, grains
or other product which dilute and weaken the functional
native wheat flour protein. Gluten is also used in the
preparation of restructured pet food products, such as
described in Canadian patent 910115.
Vital wheat gluten is also formulated into pasta
and breakfast cereals to improve their nutritional profile,
and is added to shrimp feed formulations not only as a
source of high quality protein but also in order to impart
water stability properties to the feed products.
The heat setting properties of vital wheat gluten
are also utilized in the preparation of meat analogues and
in the extension of meat, poultry, dairy and surimi based
products.
Freshly extracted wet gum gluten has a solids
content of from about 30 to about 40%. It is then normally
dried in a ring drier, which is a flash dryer of the kind as
described for example in U.S. Patent 2,559,551 (Weber)
mentioned above. The ring drying process involves extruding
wet gum gluten through a disintegrator into a recycling
current of dry gluten and hot air. The recycling gluten
prevents reagglomeration and promotes disintegration.
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Unfortunately, the conditions in this known drying
process are also conducive to the initiation of rancidity,
since drying temperatures up to about 155°C are used. Vital
wheat gluten contains a certain proportion of lipids,
typically from about 5 to about 9% on a dry basis, and these
will oxidize readily at such high temperatures, especially
in the presence of oxygen. The commercially available
gluten currently being ring dried consequently has a rancid
"wheaty" or "cereal" flavor and aroma.
Thus, the cereal flavor and aroma of such wheat
gluten limits its addition or substitution level and often
requires some reformulation in order to mask the foreign
"wheaty" or "cereal" flavor.
Other vegetable protein products also have
off -flavors. For example, U.S. patent 4,265,925 (Campbell
et al.) describes a solvent process to improve the flavor
(referred to as being "beany" or "painty") of soy protein
products. Campbell et al. propose an aqueous alcohol
solution to extract the flavor and the soluble carbohydrate
components of defatted vegetable protein flakes.
U.S. patent 4,075,361 (Oberg) teaches hot alkaline
water extraction of whole soybean in order to deactivate the
lipoxygenase enzyme responsible for the "painty" soy flavor.
U.S. patent 4,108,847 (Creinin) describes a process
for preparing a bland corn gluten product. This process
would not be suitable for the preparation of a bland vital
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wheat gluten product since in a critical step the protein
slurry is heated to about 90-100°C. This heating step would
denature vital wheat gluten proteins, making it unsuitable
for many important traditional uses, for example the
manufacture of a wheat gluten based fibrous meat-like
product, such as described in U.S. patent 4,938,976
(Shemer), or the fabricatian of a simulated meat pet food
product such as described in Canadian patent 910115.
U.S, patent 4,396,637 ((Singer) teaches a method
far processing and drying a vital wheat gluten having
improved flavor and odor but without any denaturation of the
protein. The vital wheat gluten extracted from wheat or
wheat flour in a conventional manner is dispersed in a
hydrophobic phase and dried under reduced pressure.
However, considerable capital expenditure would be required
to substitute such a drying process for the conventional
flash drying process. Also, the resulting product would
differ from conventional vital wheat gluten in that its
composition would be changed from having about 15% to having
about 50% carrier oil. Removing this ail component would
require additional expensive steps, such as solvent
extraction and steam stripping.
U.S. patent 4,645,831 (~awhon) describes a process
for improving the flavor and the color of wheat gluten
products. The gluten or gluten products are dispersed in an
alkaline water solvent phase and then extracted. The
extracted protein concentrate is re-dispersed in a suitable
solvent and further purified by ultra-filtration. This
process would add a series of additional complex steps
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to the process of starch and gluten separation, namely the
dispersion in an alkaline aqueous solvent phase, the
recovery of the solvent and the ultra-filtration. Also, the
extxa equipment needed for the ultra-filtration and the
solvent recovery systems would require large capital
expenditures.
Thus, although there has been a need for vital
wheat gluten with substantially no objectionable flavor or
aroma for many years, and various attempts have been made to
provide a suitable process for producing such gluten, the
only processes so far proposed require the addition or
substitution of expensive steps in conventional gluten
producing processes.
There is therefore still and has for a long time
being a need for a simple and inexpensive modification to
conventional gluten producing processes which include drying
wet gum gluten to enable dried vital wheat gluten to be
produced with substantially no objectionable flavor or aroma.
Tt has now been discovered that this can be
achieved by mixing an aqueous antioxidant preparation with
vital wet gum gluten after its extraction from wheat or
wheat flour by an aqueous process and prior to ids being
dried to produce dried vital wheat~gluten. The mining of
the aqueous antioxidant preparation and vital wet gum gluten
is both technically easy and also ine$pensive, requiring
minimal change to existing gluten production plants. The
cost of the aqueous antioxidant preparati~n is also
relatively inexpensive compared to the beneficial result
obtained.
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Advantageously, the antioxidant comprises
tocopherol, the antioxidant preparation comprising an
aqueous tocopherol dispersion. The antioxidant may be delta
tocopherol, gamma tocopherol, beta tocopherol or mixtures of
two or more thereof. Alpha tocopherol may also be used,
either by itself or mixed with one or more of the other
tocopherols mentioned. The tocopherol or tocopherol mixture
is preferably present in an amount in the range of from
about 20 to about 2,000, still more preferably from about 80
to about 240, parts per million by weight of the dried vital
wheat gluten product.
Use of the invention produces a bland but
functional gluten product that can be used to bind and
extend meat, poultry, surimi based and dairy products and to
prepare meat, poultry and dairy analogues.
The vital wheat gluten produced by utilization of
this invention has all of the very desirable properties of
regular vital wheat gluten but is also very bland in flavor
and aroma and is thus a suitable ingredient far the
extension of food protein products.
In order to achieve an efficient dispersion of the
antioxidant in the wet gluten phase. it is important to
introduce it at a suitable concentration. Too high
concentration makes homogeneous mixing difficult, while
using a too dilute antioxidant dispersion will result in
having to dry out more water with consequent reduced drying
throughput. For a tocopherol dispersion for example: a
suitable concentration would be in the range of from about
0:005 to about 5%, typic~.lly about 0.5%: by weight:
It should be noted that the present invention is
not suggested in U.S, patent 4,238,515 (Shemer) which
describes a process for producing a novel physical form of
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~~41.3.4
gluten containing an inert food material bound within its
matrix. The Shemer process comprises agitating mixture
consisting essentially of hydrated vital wheat gluten and a
reducing agent at a temperature below 70°C to form a
softened net-like fibrous structure, and incorporating
during said agitation the solid inert food material having
particle sire below 5 cm diameter in an amount sufficient to
obtain a ratio of gluten to inert food material of from
about 1:0.1 to 1:10. Shemer suggests that tocopherol may be
used as the reducing agent, but gives only specific examples
of sodium sulfate and ascorbic acid as reducing agents.
Shemer l.s not concerned with the flavor and aroma of gluten
produced by drying wet gum gluten as is the case in the
present invention.
Reference should also be made to the article
entitled "Tocopherols As Food Antioxidants" by Marion E.
Dougherty, 0'r. in Cereal Foods World, February 1888; Volume
33 No. 2, pages 222-3. Although this article indicates that
tocopherols are well known as antioxidants for finished food
products, it was completely unexpected that tocopherols
would function as an antioxidant for gluten when added
during the manufacture thereof as in the present invention.
As mentioned above, the problem of producing vital wheat
gluten with substantially no objectionable flavour or aroma
has awaited a satisfactory solution for many years.
Embodiments of the invention will now be described,
by way of example, with reference to the accompanying
drawings, of which:
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Figure 1 is a flow diagram of a gluten production
process incorporating the use of an antioxidant preparation
in accordance with the present invention, and Figures 2 and
3 are graphs comparing the Theology of gluten produced in
accordance with the prior art and gluten produced in the
same manner but with the use of an antioxidant preparation
in accordance with the present invention.
Referring first to Figure 1, freshly extracted
vital wet gum wheat gluten is received from a conventional
extraction process through pipe 1 and falls into the inlet
of pump 2, which is an auger-fed positive displacement
pump. An emulsion dispersion prepared by dispersing a
dispersible antioxidant product in cold water is fed through
a metering pump 3 also into the inlet of pump 2. Pump 2
mixes and pumps the gluten/antioxidant mixture into
conventional drier 4 from which flavourless gluten product
is subsequently extracted.
Figures 2 and 3 show the results of Brabender
Extensograph tests carried out on gluten produced in
accordance with the prior art and gluten produced in the
same manner but with use of an antioxidant preparation in
accordance with the present invention (as described in the
following example).
In~a Brabender Extensograph test, a reconstituted
gluten dough is formed and stretched, and elongation and
resistance to elongation are recorded. In Figures 2 and 3,
the horizontal axis indicates elongation and the vertical
axis indicates resistance to elongation.
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~~413~.4
These tests demonstrate the unique visco-elastic
properties of vital wheat gluten, and a comparison of
Figures 2 and 3 shows that these critical gluten properties
have not been affected by use of the invention.
A specific example of the invention will now be
described.
EXAI~IpLE
15 kg of a suitable antioxidant mixture, such as
Emulsion 14-SP produced by Riken Vitamin Co. Ltd. of Tokyo,
Japan, which contains about 14% active tocopherols, was
dispersed into 400 litres of cold water in a 2,000 litre
tank, and the mixture was stirred far five minutes in order
to ensure complete dispersion. The dispersion thus contains
about 0.5% by weight active tocopherols. This dispersion
was then pumped at the rate of 350 mls per minute into a
pump which was also pumping wet gum vital wheat gluten at a
rate of 32 to 37 kg per minute. The resultant gluten
tocopherol mixture was then pumped through a stainless steel
pipe to a conventional ring drier, with an inlet temperature
of 155°C and an outlet temperature of 55°C.
The resulting dry gluten was bland and devoid of
any objectionable flavor or aroma and yet still had all the
functionalities usually associated with commercially dried
vital wheat gluten.
Analyses of a control gluten,; with no added
tocopherol and gluten produced in accordance with the
invention with added tocophetol are shoran in Table 1.
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~~4~.3~.~
v.
TABLE 1
TOCOPFiEROL CONTENT OE' GLUTEN
.per 100aLof aluten)
Control Gluten Alpha Tocopherol 1.80 mg
(no added tocopherol) Delta Tocopherol 0.40 mg
Gamma and Beta Tocopherol 1.20 mg
Tnvention Gluten Alpha Tocopherol 1.90 mg
(with added tocopherol) Delta Tocopherol 6.50 mg
Gamma and Beta Tocopherol 14.30 mg
Thus, the invention gluten contains about 190 parts
per million added tocopherols by weight of the gluten.
It will be noted that gluten normally contains a
lower amount of different forms of tocopherol; such a low
amount being insufficient to prevent the production of
objectionable flavor and aroma in the conventional drying
step.
Other embodiments and egamples of the invention
will be readily apparent to a person skilled'in the art from
the foregoing description, the scope of the invention being
deffined in the appended claims.
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