Note: Descriptions are shown in the official language in which they were submitted.
--~ 2140100
METHOD FOR HEAT TREATING A BREAD BAKING
WHEAT FLOUR AND RESULTING FLOUR AND DOUGH
BACKGROUND OF THE INVENTION
This invention relates to a method for heat ~
treating a bread baking wheat flour to form a flour, ~ -
and to the resulting flour and dough having improved
baking characteristics.
It has been recognized for many years that --~
the oxidation of a wheat flour can improve the
rheological and baking performance of the flour in a
yeast leavened dough system. Freshly milled flours
tend to produce doughs which are excessively pliable
and lack the elasticity to produce optimum finished
bread characteristics. When flour is stored with free
access to the air, a slow oxidation process takes place
which is referred to as aging or maturing of the flour.
Properly matured flour produces a more lively, more
elastic dough characteristic as compared to freshly
2140100
-- 2
milled flour. Many factors such as the degree of
exposure of the flour to the air and the temperature of
the air can affect the rate of oxidation of the flour.
It has been suggested that pneumatic transfer of flour
at the mill and the bakery accelerate the oxidation
process due to the increased exposure of the flour
particles to air.
The oxidation of gluten proteins in wheat -
flour includes the oxidation of sulfhydryl groups,
which results in cross-linking of protein chains. This
cross-linking inhibits the reduction and interchange of
disulfide bonds. The effect of oxidation of gluten
proteins on the rheological properties of dough can be
demonstrated by load extension tests such as the
Brabender Extensigraph test (American Association of
Cereal Chemists 1983 Method 54-10). Extended aging of
wheat flour results in reduced dough extensibility and
increased resistance to extension using the
Extensigraph test. Chemical oxidizing agents can
directly or indirectly oxidize sulfhydryl groups of
gluten proteins when wheat flour has been hydrated and
mixed into a dough. Extensigraph tests show that
chemical oxidizing agents cause wheat flour doughs to
become less extensible and to increase in resistance to
extension. The type and level of chemical oxidant, the
amount of reaction time and the inherent properties of
specific flours all influence the degree of rheological
modification to the dough.
The chemical oxidizing agent
aziodicarbonamide (ADA) is generally added to bleached
wheat flour for bread baking at 10 ppm as a maturing
agent and can be added at up to 45 ppm. At high levels
of usage, ADA is considered an improver rather than a
maturing agent. Up to 50 ppm of the chemical oxidizing
agent potassium bromate can be added to wheat flour as
an improver, and the resulting flour is referred to as
bromated flour. The chemical oxidizing agent
2~ ~0100
L-ascorbic acid can be added to wheat flour at levels
up to 200 ppm and is considered an improver.
Chemical oxidizing agents added to flour have
little or no effect on the gluten proteins until the
flour is hydrated and mixed into a dough. The rate of
reaction of chemical oxidizing agents in a dough varies
from rapid for ADA to intermediate for ascorbic acid to
slow for potassium bromate. The varying rates of
reaction of various chemical oxidants in a dough system
make their role in a baking process differ
significantly. The rate of reaction of potassium
bromate in a dough system is relatively slow and is
most effective at the late proofing stages and early
oven stages.
The level of chemical oxidation required in
bread baking is heavily dependent on the type of
process being utilized. Processes where bulk
fermen~ation has been eliminated or reduced to a short
time are often heavily dependent on chemical oxidizing
agents. Straight dough processes where bulk
fermentation is essentially eliminated are referred to
as "no-time" straight doughs. Straight dough processes
where bulk fermentation is relatively short (less than
1 hour) are referred to as "short-time" straight ~ -
doughs. Both no-time and short-time straight dough ~
processes traditionally have relied on relatively high ~-
levels of potassium bromate. Conventional straight
dough processes where bulk fermentation is carried out
for 1~ to 2~ hours have a moderate oxidation require-
ment. Sponge and dough processes where a sponge
containing part of the total flour in the formulation -
is fermented for 3-5 hours, generally have relatively
low oxidation requirements.
The United Kingdom and Canada have removed
potassium bromate from the list of permitted food -~
additives. In the United States many bakers have
voluntarily removed potassium bromate from their ~-
2 1~0100
-- 4
formulations and replaced it with a combination of
other chemical oxidizing agents.
Potassium bromate free formulations are
typically less tolerant to variations in processing
conditions than the same formulations containing
potassium bromate. The higher the oxidation re~uire-
ment of a processes, the more noticeable is the lack of
tolerance that is experienced when potassium bromate is
removed and replaced with combinations of other oxid-
izing agents, such as ADA, ascorbic acid, or potassium
iodate.
In the 1920's and 1930's several researchers
studied the use of heat treatment to improve the bread
baking quality of wheat flour, as reported in the
following documents:
Kent-Jones, D.W. "A Study of the effect of
heat upon wheat and flour, especially in
relation to strength". Thesis presented
to London University (1926);
Herd, C.W., Cereal Chem, VIII, 1 (1931);
Herd, C.W., Cereal Chem, VIII, 145 (1931);
Geddes, W.F., Canada. J. Res., I, 528 (1929);
Geddes, W.F., Canada, J.Res., II, 195 (1930);
Geddes, W.F. Canada. J. Res., II, 65 (1930);
British Patent 180,496 (1922);
British Patent 228,841 (1925);
British Patent 300,291 (1938);
British Patent 300,537 (1938).
Chemical oxidizing agents such as potassium bromate
were economical and effective, and such chemical
oxidizing agents became widely used.
~1401û0
SUMMARY OF THE INVENTION
One object of this invention is to use a heat
treatment process to bring about the oxidation of
gluten proteins in wheat flour for bread baking. The
degree of oxidation that this process accomplishes can
be much higher then that which would be achieved by the
maturing agent ADA at the 5-10 ppm level utilized in
bleached flours. The process described below is so
effective at oxidizing gluten proteins that it can
bring a wheat flour to a stabilized oxidation state
whereby the flour will not continue to change with
storage. Stabilizing the oxidation state of the flour
will result in less variation in baking characteristics
between freshly milled flour and flour that has been
stored for variable periods of time. -
According to a first aspect of this
invention, a method is provided for improving bread
baking characteristics of a bread baking wheat flour by
drying the flour by suspending it in a heated, oxygen ~ ~
containing carrier gas having an outlet temperature in ~ -
the range of about 50~-130~C for a time sufficient to
reduce moisture content of the flour by at least 5 wt%
and to increase the ratio of extensigraph resistance to
extensigraph extensibility of the flour by at least
20%, both as compared with the initial flour. The
flour is then separated from the carrier gas to provide
a free flowing, dry powder having a reduced moisture
content and an increased value of the extensigraph
resistance/extensibility ratio as compared to the
initial flour. The heat treated flour can be mixed
with dough forming ingredients including water to form
a bread dough.
According to a second aspect of this
invention, a bread baking wheat flour is provided
comprising a gluten protein fraction, wherein an amount
greater than about 1 wt% and less than about 5 wt% of -
the gluten protein fraction is denatured, and wherein
~,.... . . ... . . . .
~ 21~01~0
the flour has a moisture content less than about 8 wt%.
The moisture content of the flour is more preferably
less than about 7% wt%.
According to a third aspect of this
invention, a dried flour of the type described below
can be mixed with other ingredients including dried
yeast to make a bread mix with an unusually long shelf
life.
As described in detail below, the preferred
embodiments of this invention provide a heat treated
bread baking wheat flour with improved extensigraph
properties and improved baking properties as compared
with the original flour. This invention is par-
ticularly useful in increasing gluten strength of
relatively low strength flours. The heat treated flour
described below has an increased shelf stability and a
reduced moisture content. The reduced moisture content
of the flour reduces shipping costs associated with
flour transport.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram of a drying appa-
ratus suitable for use with the preferred embodiment of
the method of this invention.
DETATT~n DESCRIPTION OF T~E
PRESENTLY PREFERRED EMBODIMENTS
The following paragraphs define standard
terms used in this specification and the following
claims, and then provide a description of the presently
preferred embodiments of this invention and a number of
specific examples.
Definitions
Bread dough -- A dough for making bread,
including breads such as white, whole wheat and other
breads and related yeast leavened products made from
bread type wheat flours, such as pizza crust, rolls,
~,
21~0100
-- 7
and bagels, whether frozen, refrigerated at
temperatures above freezing, or unrefrigerated.
Bread baking flour -- A flour suitable for ~'~
baking bread, including bread such as white, whole
wheat and other breads and related yeast leavened
products made from bread type wheat flours such as
pizza crust, rolls, and bagels.
Wheat flour -- A flour milled from any wheat, -
including hard, soft and durum wheats. ;~
Moisture content -- Moisture content of a ;
flour as measured by the air-oven method set out in
AACC method 44-16 (revised 10/27/82).
Ash content -- Ash content of a flour as
measured by the basic method set out in AACC method 08-
01 (revised 10/28/81).
Farinograph stability -- Dough strength as
measured by the farinograph method set out in AACC
Method 54-21 (revised 10/27/82). Stability is a
measure of a flour's tolerance to mixing, and it is
further discussed in the Farinoqraph Handbook, Burt L.
D'Appolonia and Wallace H. Kunerth, Editors tThird
Edition, 1984, American Association of Cereal Chemists,
St. Paul, Minnesota).
Falling Number -- Alpha amylase activity as
measured by the method set out in AACC Method 56-81B ~
(revised 10/12/88). ' -
Extensigraph resistance (Rm~ The maximum
height of the extensigraph curve in cm. (AACC Method
54-10, 1983).
Extensigraph extension (E) -- The total
length of the extensigraph curve in cm. (AACC Method
54-10, 1983).
Extensigraph resistance/extension ratio --
The ratio Rm~/E of extensigraph resistance to
extensigraph extension.
Straight dough bread baking process -- A
method of making bread in which all of the ingredients
2140100
are mixed to form a dough in one operation and then
given bulk fermentation prior to dividing and molding.
No-time straight dough bread baking process--
A straight dough bread baking process in which the
fermentation time prior to dividing and molding is 0-20
minutes.
Short-time straight dough bread baking
process-- A straight dough bread baking process in
which the fermentation time prior to dividing and
molding is 20-60 minutes.
Protein fraction -- The protein content of
flour, measured as a weight percent of the total flour,
as determined by AACC Method 44-15A.
Gluten denaturation -- Reduction of soluble
gluten proteins, measured as a weight percent of the
sample normalized to a 14 wt% moisture basis, as
determined by the procedure described by Orth and
Bushuk, Cereal Chem., 49:268 (1972).
General Discussion
. ,,. ~: ,, ~
This invention is based on the discovery that
by properly selecting heating conditions and time ~-~
parameters the baking properties of a flour can bé
improved by a dry heating process. The dry heating
process described below utilizes short times and
carefully controlled temperatures such that gluten ~ -
strength is actually increased. -
In the preferred embodiment of this invention
a bread baking wheat flour is treated with a drving
apparatus as shown in attached Figure 1. This drying -;
apparatus 10 includes a heat exchanger 12 which is -~
connected to a dryer column 14. Fans 16 force a
carrier gas such as air or other oxygen containing gas
through the dryer column 14. Any appropriate heat -~
source can be used to heat the carrier gas as it passes
through the heat exchanger 12, including gas fired
heaters and steam heaters. The heat exchanger 12 can
21401~0
also operate with electric heating or can utilize
heated waste gases from other processes. Preferably,
no water is added to the carrier gas, and the relative
humidity of the heated carrier gas is low.
Calculations indicate the relative humidity of the
heated carrier gas before it comes into contact with
the flour is between 2.4% and 0.1%, depending on
ambient conditions and the inlet temperature.
The dryer column 14 is designed to fit the
particular application, having a diameter determined in
the conventional manner by factors such as the evapora-
tive duty, the drying temperature and the velocity
required to convey the material. The length of the
column is determined by conventional factors to provide
the required residence time. Depending upon the appli-
cation, the dryer column 14 can be shaped and sized to
fit within an existing building or to provide the
finished product at a required position. Preferably,
the fans 16 include conventional control dampers (not
shown) to set the air volume and pressure balance at
the feed point. When the overall system pressure drop
is not high a simple single fan system can be employed. '
A feeder 18 feeds the incoming flour into the dryer
column 14 at a feed point 20. A variety of feeders can
be used including vibrating, paddle, or pneumatic type
feeders. Hoppers with appropriate discharging facili-
ties can be provided for continuous metering from batch
chargers. Conventionally, high air velocities are
employed at the feed point 20 to assist in product
entrainment and dispersion. Lower velocities are
preferably used in the subsequent dryer column 14 to
achieve an increased residence time.
The feeder 18 introduces flour into the dryer
column 14, and the flour is carried by the moving
heated air to a recycle separator 22. If desired, the
flour passing out the bottom of the recycle separator
22 can be reintroduced into the feeder 18 to repeat the
.
: -
.
: .
2140100
-- 10 --
drying process. Generally this is not done and the
entrained flour is separated from the carrier gas by a
main separator 24. This treated powder is a free-
flowing dry product which is available at the discharge
point 26 for collection or ba~ging. If desired, the
treated flour may be cooled at the discharge point 26
to ambient temperature prior to collection or bagging.
A suitable drying apparatus 10 can be
obtained from APV Pasilac Limited of Carlisle, Cumbria,
United Kingdom identified as a turbo venturi or TV
drying system. In the following examples, such a
system was arranged to maintain the flour in the heated ;
air for a residence time of 5 to 8 seconds, and to ~-
provide an inlet air temperature measured upstream of
the feedpoint 20 in the range of 128~-255~C and an
outlet or exhaust air temperature measured upstream of
the recycle separator 22 in the range of 50~-130~C. It
is believed that the TV drying system provides highly
turbulent mixing of the flour and heated air, and that
this turbulence contributes to the efficiency of flour ;~
modification discussed below. As discussed below,
these conditions have been found to provide a flour
with surprisingly good baking characteristics. The
exhaust air temperature is preferably 50~-130~C, more
preferably 50~-110~C, and most preferably 50~-100~C. -~ -
In general, the flour starts with a moisture
content in the range of 13 to 15 wt%, and moisture
content is reduced by at least 5 wt~ in the drying
apparatus 10, often to a value in the range of 2-8 wt%.
When flour with an initial moisture content of 13-15
wt% is heat treated to an outlet or exhaust temperature -~
of 90~-110~C, the final moisture content is often in
the range of 2.5-5 wt%. The flour is heated in the - -
carrier gas preferably for a time of less than one~ -
minute, more preferably for a time of less than 30
seconds, and most preferably for a time of less than 10
seconds (such as 5-8 seconds).
2l40lao
Farinograph stability is a well known measure
of dough strength, which involves forming a dough by
mixing flour and water, and then graphing the
resistance of the dough to mixing as a function of
elapsed time. Conditions are standardized so that
maximum resistance is centered at a level equal to 500
Bxabender Units (BU), and the elapsed time is measured
between the point where the top of the curve first
reaches the 500 BU line (arrival time) and the point
where the top of the curve leaves the 500 BU line~
(departure time). This elapsed time is the farinograph
stability. In general, the greater the farinograph
stability, the greater the strength of the dough and
the greater its suitability for bread baking.
Our United States patent application Serial
No. 07/868,012 describes a method for heat treating a
bread bakinq wheat flour to increase the stability of a
dough mixed from the flour. The present specification
clarifies that dough produced from flour processed by
this method shows reduced extensibility and increased
resistance to extension as compared to a dough produced
from the same flour without heat treatment. Oxidation
of sulfhydryl groups in the gluten proteins of wheat
flour is known to result in reduced extensibility and
increased resistance to extension when a dough made
from the flour is tested on the Brabender Extensigraph.
The Brabender Extensigraph is a well known
instrument for measuring dough characteristics that are
important in bread baking. Basically, a flour under
test is used to make a dough in a defined manner. Then
the dough is formed into a test piece which is clamped
in the dough holders of the Extensigraph. After a
defined rest period, the Extensigraph is started to
stretch the dough until the test piece breaks. The
load-extension curve is recorded as an extensigram,
with resistance to extension plotted on the vertical
axis and extension on the horizontal axis. Rm~ is the
~, ~
-~ 2:140100
- 12 -
maximum resistance to extension (or the maximum height
of the extensigram curve). E is the extensibility (or
the total length of the curve, from start to breaking
of the test piece). The ratio Rm~XtE is greater for
doughs with higher resistance to extension and for
doughs with reduced extensibility. -
When a flour is treated by this method the
degree of oxidation of gluten proteins can be varied so
as to meet particular requirements for the specific
flour and for the particular bread making process. The
optimum ratio of resistance to extension to extensi-
bility (~XtE) will depend on characteristics of the ~
specific wheat flour, the type of baking process, and :~-
the amount and type of chemical oxidizing agents being -;~
used in the formulation. With certain baking
processes, wheat flour treated by this method may allow
for the total elimination of chemical oxidizing agents.
In other cases wheat flour treated by this method may ~;~
allow for a reduction of chemical oxidizing agents. In
still other cases, wheat flour treated by this method
will result in improved processing tolerance and
improved finished baked products when used in potassium
bromate free formulations that contain other chemical
oxidizing agents.
An additional advantage of wheat flour -
treated by this method is the resulting increase in the -~
level of solids per given weight of flour. This ~:-
increased level of solids results in an increased yield
of dough per 100 pounds of flour. This increase in ;~
dough yield per 100 lbs. of flour holds true when the
wheat flour is scaled on an "as is" moisture basis as a
direct replacement for the equivalent percentage of
wheat flour in a formulation or when scaling the flour
on a solids corrected basis to achieve the same level
of flour solids as would be in wheat flour at a
standard moisture content of 14%.
~ ~ 2:~ ~01~0
- 13 -
An additional advantage is that wheat flour
treated by this method may in certain circumstances
allow for a lower protein content wheat flour (on 1~%
moisture basis comparison) to be utilized in place of
higher protein wheat flour. This is particularly an
advantage in hearth baked bread products where higher
protein wheat flours are typically used to allow the
dough to hold a specific shape in the absence of a pan.
Extensigraph Tests
In the following Examples 1-5, flour was heat
treated in a dryer as described above at various inlet
temperatures and at various outlet or exhaust
temperatures. In general, the inlet temperature was
controlled by adjusting the amount of heat supplied by
the heat exchanger 12 within the range of 128~C to
255~C. The exhaust or outlet temperature was measured
with a thermocouple upstream of but near the recycle
separator 22 and was adjusted for various values
between 50~C and 130~C by controlling the product feed
rate to maintain the desired exhaust temperature. Air
was used as the carrier gas, though othex oxygen-
containing gases are believed suitable. The flour was
subjected to elevated temperatures in the dryer column
14 for approximately 5 to 8 seconds, and the tempera-
ture of the heat treated flour as measured with a
thermometer at the discharge point 26 was about 10~C
less than the outlet temperature. The heat source was
separated from the flour from by the heat exchanger 12.
Flour was heat treated at the rate of 2200 pounds per
hour.
It is known that storing a flour over a long
period at low or room temperature will increase the
farinograph stability of the flour to a limited extent.
This effect was taken into account in the following
examples by starting with examples and controls from
the same batch of flour and performing the tests on the
,, ,~ " ,~
~,,
1401~0
same day for both the heat treated flours and the
respective control flours.
Examples 1-5 (Table 1)
A 100 percent hard red winter wheat flour was
divided into six samples. The control sample was
untreated, and was analyzed as described in Table 1 at ~-~
the same time as the treated flours of Examples 1-5. -~
The flours of Examples 1-5 are heat treated in the
manner described above with inlet temperatures and -~
exhaust temperatures as stated at the top of Table 1.
In this case, the heat exchanger 12 was heated by
direct gas fire. The flour was substantially
unmodified and was not bleached, enriched or treated
with enzymes or bromate.
The samples started with a moisture content ~
of 13.6 wt%, an ash content of 0.473 wt% (calculated ~ -
based on a moisture basis of 14%), a protein content of
10.4 wt% (calculated on a moisture basis of 14%), and a
falling number of 379 (calculated on a moisture basis
of 14%). For ease of conversion, all following ash
content, protein content, and falling number
determinations are adjusted to a 14% moisture basis.
Farinograph and Extensigraph tests were performed on ;~
the control sample (Control 1) and Examples 1-5 as set
out in Table 1. Farinograph tests were performed in
accordance with AACC Method 54-21 (constant dough
weight method, flour scaled on a 14% moisture basis).
Extensigraph tests were performed in accordance with
AACC Method 54-10 (Flour scaled on a 14% moisture basis
and mixed on farinograph by the constant dough weight
method to farinograph peak; extensigraph measurements
taken after 45 minute rest period).
~s ~
0 1 ~ 0
- 1 5
TA3LE 1
SAMPLE CONTROL 1EX. 1 EX. 2 EX. 3 EX. 4 EX. 5
Inlet/Outlet Temp (~C) ~A 178~/90~ 182~/100~187~/110~ 192~/120~ 224~/130~
Moisture ~wt%~ 13.6 4.5 3.5 2.7 3.1 2.0
Farinograph Stability 19.9 29.4 32.5 38.0 42.3 43.0
R~uy ~cm) 6.2 6.5 7.6 8.3 8.9 9.3
E (cm) 17.5 16 15 13.2 11.2 10.7
RnU~/E ~354 .400 .506 .628 .794 .869
Table 1 shows Extensigraph data for a bread
baking wheat flour before heat treatment and after
treatment over a range of carrier gas inlet tempera-
tures from 178~C to 224~C and outlet temperatures from
90~C to 130~C. Table 1 also lists the farinograph
stability values and moisture contents for the control
flour and at each level of heat treatment. Both the
extensigraph and farinograph tests were conducted on a
solids corrected basis (14% moisture basis). As the
heat treatment level increased the farinograph
stability increased and the ratio of resistance to
extension (Rm~) over extensibility (E) increased. For
this particular flour, significant increases in
resistance to extension did not occur with flour until
an outlet temperature of 90~C was achieved. A carrier
gas outlet temperature greater than 130~C but less than
140~C may result in denaturation of the gluten to the
point that gluten can no longer be washed from the
flour and a dough can no longer be formed from the
flour when it is hydrated and mixed.
Table 1 confirms that the heat treatment
process described above increases the gluten strength
of the treated flour as compared to the control flour.
Examples 6-9 (Table 2)
A mixture of hard red winter wheat and hard red
spring wheat flour was divided into five samples. The
control sample was left untreated, and was analyzed as
"- . . .: . . . , - -
,~ :, . .. ..
~ 2140100
- 16 -
described in Table 2 at the same time as the heat
treated flours of Examples 6-9. The flours of Examples
6-9 were heat treated in the manner described above
with exhaust temperatures as stated in Table 2. The
flour was substantially unmodified, and was not
bleached, enriched or treated with enzymes or bromate.
The samples started with a moisture content of 14.1
wt%, an ash content of 0.518 wt%, a protein content of
11.9 wt% and a falling number of 430. The flours were
tested as described above in connection with Ex. 1-5, ~
and the results are set out in Table 2. ~-
TABLE 2 ~;
SAMPLE CONTROLEX. 6EX. 7 EX. 8 EX. 9
Out~et Temp (~C) NA 50~ 60~ 70~ ~oo
Moisture (wt~,~) 14.1 6.7 5.9 4.6 4.1
Farinograph Stability16.521.722.7 25.3 27.8
R~ y (cm) 8.2 10.111.011.912.8
E (cm) 23.4 23.421.520.421.1
R~ y/E .350 .432.512.583.607
', : ;,::
As before, both the extensigraph and
farinograph tests were conducted on a solids corrected
basis (14% moisture basis). As the outlet temperature
increased from 50~C to 80~C, the farinograph stability - '~
and the ratio R~X/E increased. Significant increases
in both were obtained with all outlet temperatures,
indicating that gluten strength can be increased with ~;
outlet temperatures as low as 50~C. ~ ~
' '
Example 10 (Table 3)
A wheat flour made of a blend of hard red winter
wheat and hard red spring wheat was divided into a
control and a sample. The control was untreated, while
the sample was heat treated in the manner described
above with an outlet temperature of 80~C to form Ex.
10. hx. 10 and the control were tested, with the
results shown in Table 3.
-- 214010~
Table 3
Sample ControlEx. 10
Outlet,temp. (~C) NA 80~
Moisture (wt%)13.6 6.4
Farinograph 16.2 20.5
Stability
RMAX (cm) 6.1 10.3
E (cm) 21.5 23.1
RMAX/E .283 .446
Table 2 shows that the ratio RMAX/E has increased by
58% for Ex. 10 as compared with the control. Increases
of greater than 10% in this ratio are expected for this
flour with outlet temperatures of 70~C.
Gluten Denaturation Tests
Heat treatment of a wheat flour at a carrier
gas outlet temperature within the preferable range of
80~-100~C causes a slight decrease in the amount of
soluble gluten proteins and an associated increase in
the amount of insoluble residue protein as measured by
the gluten denaturation test described by Orth and
Bushuk, Cereal Chem., 49:268 (1972). This test
measures denaturation of gluten by measuring the loss
of protein solubility in dilute acetic acid. At the
most preferred conditions for carrier gas outlet '
temperature this reduction in soluble protein (and
therefore the increase in denatured gluten) is greater
than 1% but no more than 5% as compared to a control
flour. Denaturation on a small scale has been found to
be advantageous to bread baking characteristics. Of
course, excessive denaturation has an adverse effect on
bread baking characteristics.
The decrease in protein solubility resulting '~'
from the heat treatment of flour is believed to be due
to increased aggregation of the proteins. Increased
,,~.. - .. : . :
.. . . .
,~
2~0100
- 18 -
cross-linking of the protein chains may be responsible
for the aggregation, but other mechanisms are possible.
In order to assess the extent to which the
heat treatment described above denatures gluten -~
proteins in flour, a flour made from a blend of harA
red winter wheat and hard red spring wheat was divided
into a control sample (which was not heat treated) and
three test samples (which were heat treated as -
described above with outlet carrier gas temperatures of
90~, 110~ and 130~C, respectively). The Orth and
Bushuk test described above was then performed on all
four samples, with the following results:
Sample Outlet Gas So~ub~e Protein ~as Standard % Reduction in .:
Temp (~C) a ~tX of sample, Deviation Soluble Protein
normalized to a as compared to
moisture basis of the Control
14 utX) Sample
Control NA 8.16 0.02 0
Sample
Test Sample 1 90D 7.92 0.02 2.9X
Test Sample 2 110~ 7.55 0.10 7.5X
Test Sampl.e 3 130~ 7.11 0.00 12.9X
:: ~ ::. '~
These tests confirm that approximately 3% of the gluten
of the flour of Test Sample 1 was denatured, assuming
that none of the gluten of the control sample was
denatured. This small amount of denaturation has been
found to provide important baking advantages as ~; -
described below. The moisture content of the flour of ;;~
Test Sample 1 was less than 7 wt%.
. . ., - - ~ : ~ : : , ,
~1~0100
Baking Tests
Example 11: French Hard Rolls by Traditional
French Process with No Added
Chemical Oxidation
Wheat Flour Type: Milled from Blend of Hard Red
Winter and Hard Red Spring Wheat
Properties (Control 2)
Moiqture 14.0~
Protein 12.1% (14~ m.b.)
Ash 0.466~ (14~ m.b.)
Falling Number 374 (14$ m.b.)
Farinograph Absorption 61.1%
Farinograph Stability 18.0 minutes
Extensigraph Resi~tance 6.5 cm (45 min. re~t)
Extensigraph Extensibility 20.0 cm (45 min. re~t)
Resistance/Exten~ibility Ratio .325
The above flour was heat treated as described
above at an inlet temperature of 150~C and an outlet
temperature of 90~C. The analytical and rheological
properties were measured as follows:
Properties (Heat Treated Ex. 11)
Moisture 4.5%
Protein 12.1% (14% m.b.)
Falling Number 0.466% (14% m.b.)
Farinograph Absorption 61.5~
Farinograph Stability 28.9 minutes
Extensigraph Resi~tance 10.0 cm
Extensigraph Extensibility 13.5 cm
Re~istance/Extensibility Ratio .740
The flours (Control 2 and Ex. 11) were baked using the
following formulation and procedure:
A. Formulation "'
Flour* (14% m.b.) 750 grams
Water* 435
Compressed Bakers Yeast 22.5
Salt 15
All Purpose Vegetable Shortening 11.25
Granulated Sugar 15
* amount of flour and water actually scaled was
corrected so as to give the equivalent amount
of solids as 750 grams of flour at 14%
moisture content. For the heat treated flour
this amounted to 676 grams of flour and 509
grams of water.
,. . ...
~ 2140~00 ~:
- 20 - ~ :
B. Procedure
(1) Flour and water were mixed on speed 1 of a ~
Hobart A-120 mixer with a McDuffy bowl and :
two prong beater for three minutes; :: -
(2) Flour and water dough were placed in an :~
enclosed container for 20 minutes at ambient ~:
temperature;
(3) The flour water dough was then returned to
the mixer and salt, shortening, and sugar~ :
were added to the dough and mixed for 1
minute on speed 1 and 2 minutes on speed 2;
(4) Yeast was then added and the dough was mixed
2 minutes on speed 1 and then six minutes on
speed 2 to the point of optimum development;
(5) Dough was fermented for 30 minutes in a
cabinet at 81~F and 87% relative humidity;
(6) Dough was scaled to 2.5 ounces, rounded by
hand and allowed to rest 10 minutes at
ambient temperature; ::
(7) Dough was then molded by hand and placed on a . :~
corn meal covered cloth and proofed in a
cabinet at 81~F and 87% relative humidity for
70 minutes;
(8) The dough pieces were given a 1/4 inch cut
down the length of the top 1/2 inch from ~ach ~ :~
end of the dough piece;
(9) Usinq a peel board the dough pieces were
transferred to the hearth of a gas fired oven
and baked for 18 minutes at 425~ with light :;~
steam for the first 5 minutes;
(10) After baking the rolls were cooled for 30
minutes prior to taking volume readings by -~
rapeseed displacement and evaluation for
guality.
C. Results
Volume (average volume per roll) : ~ ~
Control 2 505 cc : ~:
Ex. 11 605 cc :.:
Quality Ranking (scale of 1-10 with 10 being
highest or most desirable)
Volume --, -
Control 2 6 ~
Ex. 11 9 -:-~;
Crumb color -.
Control 2 7 ~-~
Ex. 11 8
Crumb Grain .
Control 2 6.5
Ex. 11 7.5
Texture
Control 2 7 :: :~
Ex. 11 8 :-
Overall Quality :~
~140100
Control 2 6.5
Ex. 11 8
The heat treated flour of Ex. 11 showed significantly
better performance than the flour of Control 2. The
improvement was consistent with what would be expected
with increased levels of oxidation of the gluten
proteins in wheat flour.
Example 12: Conventional Straight Dough Kaiser Roll
Wheat Flour Type: Milled from Blend of Hard Red
Winter of Hard Red Spring
Pro~erties (Control 3)
Moisture 13.6%
Protein 12.3%
Ash 0.478%
Falling Number 347
Farinograph Absorption61.7%
Farinograph Stability 16.2 minutes
Extensigraph Resistance6.1 cm
Extensigraph Extensibility 21.5 cm
Resistance/Extensibility Ratio .283
The above flour was heat treated as described above at
an inlet temperature of 150~C and an outlet temperature
of 90~C. The analytical and rheological properties
were measured as follows:
Properties (Heat Treated Ex. 12)
Moisture 5.1%
Protein 12.3%
Ash 0.478%
Falling Number 336
Farinograph Absorption62.0~
Farinograph Stability 28.5 minutes
Extensigraph Resistance11.1 cm
Extensigraph Extensibility 14.0 cm
Resistance/Extensibility Ratio .742
The flours (Control 3 and Ex. 12) were baked using the
following formulation and procedure. The flour before
heat treatment was also baked with 15 ppm potassium
bromate. The flours were malted (0.06% malted barley
flour).
A. Formulation
Flour* ~4% m.b.)1000 grams
Water* 500
Compressed Bakers Yeast25
Salt 17.5
. ~ , ~ . .
~140100
Granulated Sugar 45
Diamalt 20
Whole Egg 40
Corn Oil 40
* amount of flour and water actually scaled was
corrected so as to give the equivalent amount
of flour solids as 1000 grams of flour at 14%
m.b. For the control flour this was 995
grams of flour and 505 grams of water. For
the heat treated flour thi was 906 grams and
594 grams.
B. Procedure
(1) Ingredients were mixed on speed 1 for 3
minutes and on speed 2 for 9 minutes for
Control 3 and 11 minutes for the heat treated
Ex. 7 using a Hobart A-120 mixer with a
McDuffy bowl and a three prong beater;
(2) The dough was then fermented in a cabinet set
at 86~F for 2 and 1/4 hours; -
(3) The doughs were then scaled to 2.5 ounces and - ;
rounded by hand and allowed to rest 7
minutes;
(4) The dough balls were then stamped using a ~-
Kaiser roll stamp and placed cut side down on
a cloth cover with corn meal;
(5) The doughs were then proofed in a cabinet at
86~F and 87% relative humidity for 90 minutes
(6) The proofed dough was placed cut side up on a
wood peel board and transferred to the hearth
plate of a gas fired oven and baked at 450~F
for 14 minutes with light steam for the first
5 minutes; -~
(7) one hour after cooling the rolls were
measured for volume by rapeseed displacement
and evaluated for quality.
C. Results
Volume (average of two rolls) : .. ~:
Control 3 428 cc
Control 3 +15 ppm potassium bromate 420 cc
Heat treated Ex. 12 437 cc -~
Quality p~nking ( scale of 1-10 with 10 being highest
or most deairable)
Volume
Control 3 9
Control 3 +15ppm potasaium bromate 9
Heat Treated Ex. 12 9
Boldness
Control 3 7 (sl.flat) .
Control 3 +15ppm potassium bromate 9 :
Heated Treated Ex. 12 9
~ 2140100
- 23 -
Separation of Cut
Control 3 6 (blinding)
Control 3 +15ppm potassium bromate 9
Heated Treated Ex. 12 9
Overall Quality
Control 3 7.3
Control 3 +15ppm pota~sium bromate 9
Heat Treated Ex. 12 9
The heat treated flour of Ex. 12 showed significantly
better performance than the flour of Control 3. This
type of improvement is consistent with an increased
level of oxidation of the gluten proteins in the flour.
Example 13: No-Time Straight Dough with Retardation
Step Using Commercial "Bromate Replacer"
The same flours as in Example 12 (Control 3 and heat
treated Ex. 12) were baked in the following formulation
and procedure. These flours will be referred to as
Control 4 and Ex. 13, respectively.
A. Formulation i.
Flour* (14~ m.b.) 1000 grams
Water* 550
Compressed Bakers Yeast 30
Salt 20
~ranulated Sugar 20
All-Purpose Veg. Shortening 20
NBCT-1 Improver** 10
* amount of flour and water actually scaled
was corrected so as to give the equivalent
amount of solids as 1000 grams of flour at
14% moisture content. The actual amount
scaled for the control was 995 grams of
flour and 555 grams of water. For the
heat treated flour 910 grams of flour was
scaled and 640 grams of water.
** NBCT-1 Improver is a combination of
ascorbic acid, ADA, potassium iodate and
fungal enzvmes marketed by Caravan
Products.
B. Procedure
(1) The ingredients were mixed on speed 1 for 2
minutes and on speed 2 for 6 minutes on a
Hobart A-120 mixer with a McDuffy bowl and a
two prong beater;
(2) The doughs were divided to 2.5 ounces,
rounded by hand and allowed to rest at
ambient conditions for 10 minutes;
(3) The dough balls were then stamped by a Kaiser
stamp and placed cut side down on a cloth
J~
~19L0100
-- 24 --
cover with corn meal and retarded for 24
hours;
(4) After 24 hours the doughs were taken out of
the retarder and allowed to sit at ambient
temperature for one hour prior to being
proofed in a cabinet at 86~F and 8796 relative
humidity for 90 minutes;
(5) After proofing the dough pieces were trans-
ferred to the hearth plate of a gas fired
oven with the cut side up using a peel board
and were baked at 450~F for 14 minutes with
light steam for first 5 minutes;
(6) One hour after cooling the volume of the
rolls was determined by rapeseed displacement
and the rolls were scored for quality charac-
teristics.
C. Results
Volume
Control 4 370 cc
Heat treated Ex. 13 395 cc
Quality Ranking (scale of 1-10 with 10 being
highest or most desirable) ~ ~
Volume -
Control 4 7
Heat Treated Ex. 13 8 -
Boldness
Control 4 7 (sl. flat)
Heated Treated Ex. 13 8 --
Separation of Cut
Control 4 7 (sl. blind)
Heated Treated Ex. 13 8
Overall Quality
Control 4 8
Haat Treated Ex. 13 7
The heat treated flour of Ex. 13 showed significantly
better performance than the flour of Control 4. This
type of improvement was consistent with an increased
level of oxidation of the gluten proteins of the flour.
~xample 14: Cuban Style Bread Using Heat Treated
Flour with Ascorbic Acid, ADA and Fungal
Amylase Added.
The same flours as in Example 12 (before ans~ after heat
treatment) had 90 ppm ascorbic acid, 45 ppm ADA, and
1/2 ounce of Doh-Tone 2 (fungal amylase from Aochem
N.A.) added to them. The resulting flours are identi~
fied as Control 5 and Ex. 14, respectively. A high
gluten flour (13.6% protein) that was malted and -~
bromated at 50 ppm (typical flour for Cuban style
bread) was also evaluated. The following formulation
and procedure were utilized~
~ : .-
i ..,
21401~0
- 25 -
A. Formulation
Control 5 Heat Treated Ex. 14
Flour ("a~ 13" moi~tu~e
ba~i~) 1000 gram3 1000 grams
Water 480 (520 for
high gluten) 600
In~tant Active Dry
Yeast (SAF) 56 45
Salt 20 28
Lard 100 120
Note: In this example the flour was scaled on an
"as is" moisture basis and therefore the heat
treated flour with the lower moisture content and
greater solids content required more water than
the control flour. To keep formulation balanced
the levels of yeast, salt and lard were increased
for the heat treated flour.
B. Procedure
(1) The ingredients were mixed for 3 minutes on
speed 1 of a Hobart A-120 mixer with a
McDuffy bowl and a two prong beater;
(2) The dough was then rested for 15 minutes at
ambient temperature;
(3) The dough was then sheeted 11 times on a
National to simulate a dough-break type
developer;
(4) After the last pass of the sheeter the
sheeted dough piece was laid on the bench and
cut into four 16 ounce pieces;
(5) The dough pieces were molded by hand into 28"
long cylinders and placed on wooden peel
boards;
(6) The dough was retarded (refrigerated at 45~F)
for 24 hours and then proofed at ambient
conditions for approx. 3 hours;
(7) The proofed doughs were transferred to the
hearth plate of a gas fired oven and baked at
450~F for 14 minutes with light steam for the
first 5 minutes.
Evaluation of the fin;shed baked breads indicated that
the bread made with the heat treated Ex. 14 was accept-
able and as good a ~uality as the bread made with the
high gluten flour treated with 50 ppm of potassium
bromate. The control flour ~Control 5) produced a loaf
with lower volume and a more dense crumb structure
compared to the heat treated flour (Ex. 14) and the
high gluten flour.
2~ ~01~0
- 26 -
The resting period of step 2 can be increased
to a time greater than 20 minutes if desired.
Example 15: Straight Dough White Pan Bread With No
Added Chemical Oxidation (1~ hour
fermentation)
The flours of Table 2 were used in the following
formulation and straight dough procedure to bake white
pan bread:
A. Formulation
Flour* 700 gms
Water** 427 mls
Yeast 21 gms
Non-Bromated Yeast Food 3.5 gms ~-
Salt 14 gms
Sugar 42 gms
Vegetable Shortening 19.95 gms
Atmul-500 1.05 gms
*Flour usage based on 14% moisture flour -
**Water usage varies depending on the correction
to 14% moisture flour.
:: :. . ~:
B. Procedure
(1) Liquid ingredients followed by the dry
ingredients were placed in a Hobart A-120 two
prong McDuffy mixing bowl.
(2) Samples were mixed on low speed for 1 min.,
followed on second speed for 6 mins. to
produce full development of the dough.
(3) The dough piece was allowed to ferment at 86
deg F with light humidity for 90 mins.
(4) Divided the dough piece into scaling weight
- of 539 gms. This formula usually allows for
the production of two dough pieces at this
amount. ;
(5) Sample dough pieces were sheeted at 3/8"
setting followed by a sheet at 3/16".
(6) Dough pieces were trifolded and allowed to
rest for 17 mins before machine moulding.
(7) Machine roller settings utilized were #l
roller-0.2, setting for #2 roller-0.1. -
Pressure board in and out were set at 1 5/8".
(8) Dough pieces were placed through the machine -~
moulder after the 17 mins rest.
(9) Placed in pans and placed in proof cabinet
set at 110 degrees F with enough humidity to
keep doughs at 70% or better.
~ :
2140100
(10) Samples removed after obtaining a height of
1/4'l above the pan.
(11) Bakes in a rotating gas oven set at 400
degrees for 18 mins.
(12) Bread samples ; ~~;ately depanned and
allowed to cool for 1 hour before bagging.
C. Results
The resulting white pan bread was evaluated
as to seven important characteristics, and a weighted
score was generated as follows:
Volume 25~
Crumb cell size, ~tructure and 25%
unifoxmity
Dough handling 15%
Mixing tolerance 15%
Crumb texture and body10%
Symmetry 5%
Crumb brightness and color 5%
The resulting bake volumes and weighted
scores were as follows:
SamPle Volume(cc) Score
Control 2600 82
Ex. 6 ,'50~C'2688 82
Ex. 7 ,60~C 2750 86
Ex. 8 70~C 2663 77
Ex. 9 80~C, 2563 72
These tests indicate that heat treatment with
an outlet temperature of 60~C was optimal for this
application. Such lower outlet temperatures cause the
flour to mature to a degree that could be obtained by
natural aging of the flour. This is in contrast to the
higher outlet temperatures discussed above, which
modify the flour to a greater extent than natural
oxidation, and which cause conformational changes in
the flour proteins as indicated by denaturation tests.
ADA is normally added to flour at 5-15 ppm as
a maturing agent, but ADA may have marketing or
regulatory disadvantages now and in the future. The
ability to accelerate natural oxidation by heat
treatment is therefore advantageous.
'- " '~' ":' "''
' ''~"'~.'",
r 2~ 40100
- 28 -
Example 16: Sponge And Dough White Pan Bread With No
Added Chemical Oxidation
The flours of Table 2 were used in the
following formulation and sponge and dough procedure to
bake white pan bread: ~
: ,- ";
A. Formulation
Sponge: Flour* 490 gms
Non-Bromated Yeast Food 3.5 gms
Yeast 17.5 gms
Atmul-5003.5 gms
Water**272 mls
Dough: Flour* 210 gms
Whey 21 gms
Corn Sugar 21 gms
Wytase 1.75 gms
Vegetable Shortening 17.5 gms
Salt & Sugar Solution*** 104 mls
Water** 79 mls
*Flour is adjusted on a 14% Moisture Basis
**Water applied in this formula is at a 61%
Absorption for 700 grams of flour.
***Salt & Sugar Solution is prepared using the
following ingredients: 240 gms of salt
600 gms of sugar
1200 mls of tap water
From this formula, 104 mls are utilized in each -
dough for the given sponge & dough formula.
B. Procedure
(1) ~iquid ingredients followed by the dry ~ --
ingredients were placed in a Hobart A-120 two ~ ~
prong McDuffy mixing bowl. -
(2) Sponges were mixed on low speed for 1 min, 1
min on second speed.
(3) The sponges-were allowed to ferment in the
cabinet for 4% hrs at 86 deg F and with light
humidity.
(4) Sponges were removed and introduced to the
mixing bowl along with the dough ingredients.
Sponges were added to the remix dough
ingredients in three equal amounts during the
1 min mix on low speed.
(5) Mixer was placed in second speed and the
samples were mixed until optimum development.
For this series of samples as an example, 9
to 10.5 mins were needed for optimum
development.
... .. : ~ . - , .; ,
,- .~ ,.: ,. . .
- 21~L01~0
-- 29 --
(6) After mixing the doughs to full development,
they were placed back into the fermentation
cabinet for 35 additional minutes.
Conditions of temperature and humidity
remained the same as the previous 4~ hour
ferment.
(7) Samples were removed from the ferment cabinet
and divided into 520 gm dough pieces. This
formula allows for the production of two
dough pieces at this amount.
(8) Sample dough pieces were allowed to rest on
the table for 6 mins prior to sheeting.
(9) Dough pieces were sheeted at 3/8" setting
followed by a sheet at 3/16".
(10) Dough pieces were trifolded prior to placing
through the machine moulder.
(11) Machine roller settings utilized were #1
roller-0.2, setting for #2 roller-0.1.
Pressure board in and out were set at 1 5/8".
(12) Dough pieces were then placed through the
moulder and panned prior to proofing.
(13) Placed the pans in a proof cabinet set at 110
degrees F with enough humidity to keep doughs
at 70% or better.
(14) Samples were removed from cabinet after
obtaining a height of 1/4" above the pan.
(15) Baked in a rotating gas oven at 400 degrees
for 18 mins.
(16) Bread samples were immediately depanned and
allowed to cool for 1 hours before bagging.
C. Results
The resulting white pan bread was evaluated
using the same weighted score as in Example 15. The
resulting volumes and weighted scores were as follows:
Sample Volume(cc~ Score
Control 2775 88
Ex. 6 (50~C~ 2863 92
Ex. 7 (60~C) 2875 86
Ex. 8 (70~C) 2788 72
Ex. 9 ~80~C) 2563 59 ;~
These tests indicate that heat treatment with
an outlet temperature of 50~C was optimal for this ~-
application. This is consistent with the fact that
sponge/dough processes and conventional straight dough
processes have lower oxidation requirements than do
short time and no-time straight dough processes. -; -
. ,. ::,. -: -.
'' ' ' ' '''
-,,,~; ,. ..
~ 2~401~0
- 30 -
Yeasted Bread Mix Tests
Flour was heat treated and dried with the
apparatus of Figure 1 to a moisture content of 4-5 wt%.
The dried flour was mixed with instant active dry yeast
and other ingredients to make a bread mix which is free
of chemical oxidizing agents, and the shelf life of
this mix was compared with comparable mixes made with
regular flour at 13-15 wt% moisture content or
conventionally dried flour at 9-11 wt% moisture
content. Shelf life is limited by yeast activity, and
the low moisture content of the mix made with the flour
of this invention results in a surprisingly long shelf
life.
Comparative tests of shelf life were made
with bread mixes made with the following formulation:
Inqredient Wt.%
Flour 82.20 -~
Sugar, fine granulated 8.30
Vegetable shortening, all 3.00
purpose plastic
Milk, nonfat dried 3.00
Yeast, instant active dry 1.95
Salt, fine blending 1.55
100.0 ~ ;
Ten ounces of this dry mix when mixed with 3/4 cup of
water in a bread machine gives a one pound loaf of
bread.
In general, the amount of dry yeast can vary
between 0.75 wt.% and 3.0 wt% of the mix, the amount of
flour can be between 70 wt% and 90 wt%, and the mix can
include other constituents as appropriate for the
application. The flour of this invention at a moisture
content of 4-5 wt% provides a yeasted bread mix with a
~ 21~0~00
- 31 -
shelf life three times greater than a comparable
yeasted bread mix made with regular flour at 13-15 wt%.
Conventionally dried flour at 9-11 wt% moisture content
only marginally improves the shelf life of the mix as
compared to regular flour.
In general, the method of this invention can
be used to dry flour to a moisture content lower than 8
wt%, and the resulting dried flour can be mixed with
dry yeast to produce a yeasted bread mix with an
improved shelf life.
Blended Flour Embodiments
If desired, the heat treated flours described
above can be blended with conventional flour that has
not been heat treated. The resulting blend often
exhibits improved baking characteristics as compared
with the conventional flour prior to blending. Such
blending can be used to increase the strength and
baking quality of a weak flour, to retain required
baking functionality when higher protein flour is
partially replaced with a lower protein, heat treated
flour, or to modify the baking characteristics of a
flour for a specific baking application.
Blending proportions will vary widely,
depending on the flour, the heat treatment, and the ~ ~-
baking application. It is anticipated that blending
ratios (heat treated flour: conventional flour) in the
range of 5:95 to 75:25 will be particularly useful.
Heat treated flour that has been partially denatured as
described above with higher temperature heat treatment
(outlet temperatures of 80-130~C) is particularly well
suited for blending.
For example, flour heat treated to an outlet
temperature of 130~C may be blended with conventional ~-
flour at a ratio of 5:95 to 10:90. In another example,
flour heat treated to an outlet temperature of 90~C may
be blended with conventional flour at a ratio of 50:50. -~
''' ' :~
21~0100
- 32 -
Blending provides a number of advantages.
Flour can be heat treated in one location and then
shipped to another location for blending. This
approach may have cost advantages over shipping special
wheat into a location in need of higher strength flour.
Additionally, blending reduces the amount of flour to
be heat treated, and therefore the associated capital
and operating costs.
Certain of the following claims include a
mixing step in which heat treated flour is mixed with
dough forming ingredients. This mixing step is
intended to be interpreted such that the dough forming
ingredients can include untreated flour, whether mixed
with the heat treated flour early (prior to shipment to
the user) or late (at the time the dough is formed).
Conclusion
As should be apparent from the foregoing
examples, the heat treatment process of this invention
produces an improved flour that, depending upon the
baking process and the specific wheat flour used, may
allow for the elimination of all chemical oxidizing '
agents. Alternately, the method and flour of this
invention allow for improved baking performance and
tolerance in formulations that contain chemical
oxidizing agents such as ascorbic acid, ADA, and
potassium iodate as a replacement for potassium
bromate.
The optimum heat treatment parameters have
been found to vary, depending to a large extent on the
baking process being used. No-time and short-time
straight doughs have a high oxidation requirement, and
in many cases the degree of modification brought about
by an outlet temperature of 80-100~C is preferred.
Baking processes such as sponge and dough have a lower
oxidation requirement, and the preferred outlet
,~ . :
: ' ,
. . .
21401~
- 33 -
temperature is also lower, often in the range of 50-
70~C
The heat treatment process and flours
described above eliminate the undesirable baking
characteristics of freshly milled flour and produce a
flour in a stable oxidation state which will tend not
to oxidize with storage as is the case with ordinary
flour. By stabilizing the flour in this way, more
uniform processing characteristics can be obtained at
the bakery as the bakery changes from one lot of flour
to another that differ in age. The heat treatment
method and flour described above provide improved
rheological dough properties including an increased
tolerance to mixing as measured by the Brabender
Farinograph and an increase in the resistance to
extension and a decrease in extensibility as measured
by the Brabender Extensigraph.
The examples set out above are intended to
illustrate but not to limit the scope of this ;~
invention, which is defined by the following claims,
including all equivalents.
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