Note: Descriptions are shown in the official language in which they were submitted.
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Field of Invention
The present invention relates to baking and in
particular, dough formulations and baking processes which utilize
yeast as the leavening agent.
Bread and related bakery products such as rolls,
generally known as "yeast goods", are produced from doughs leavened
with yeast. The leavening action is accomplished via the yeast
enzyme systems which convert simple sugars, such as dextrose,
sucrose and fructose mainly into carbon dioxide and alcohol. The
principle factor in the dough-raising action of the yeast is the
carbon dioxide, while the alcohol produced tends to escape from the
dough and is entirely eliminated in the process. The size of the
finished product is largely determined by the gas-production rate
during the dough rise in the pan. The proper mellowing of the
dough during the conditioning stages is due partly to the
stretching caused by the yeast action: on the other hand, an
increase in acidity and the creation of certain by-products in the
ermentation process tend toward reducing dough elasticity. The
type and purity of the strain of yeast used are obviously important
in securing the proper balance between the mellowing and final
leavening activities.
For the yeast to function at all, there must be
carbohydrates, i.e. sugar substrates, present in the dough
formulation. The amount of available sugar present in most flours,
especially in ~orth America, is very low and, in fact, almost
negligible whilst the amount of sugar used in such "yeast goods"
bakery products is generally high; for example as high as 20%
based on flour weight. Dough formulations for bread usually
contain from 2% to 6~ sugar and even up to 10% in Canada, whilst
sugar contents up to 12% are not uncommon in the United States
where bread in general is somewhat sweeter.
It may be pointed out that the sugar content is not
essential to the basic yeast action. This would occur to a limited
extent in sugarless doughs as for example in the production of some
ethnic yeast goods, especially breads. However, that bread is not
of a typical ~orth American type. To obtain such standard bread
and in the time-restraint applied by standard ~orth American
processes, in particular, in the relatively short period between
mixing the dough and introducing same to the oven, relatively rapid
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gas production must be obtained and this requires a sugar-su~Dstrate
concentration of over 2%, and usually about 4~ or more in the
dough, based on flour weight. It is only under these conditions
that the required gas production rate is achieved and the desired
crust colour subsequently developed.
The dough formulations usually contain from 2 - 3~% by
weight of yeast based on flour weight. However, it has been found
that yeast action is inhibited by the higher sugar levels and it is
necessary in such cases to increase the yeast concentration to
overcome the reduced efficiency of the yeast.
The required sugar substrate has traditionally been
included in the formulations in the form of, for example, sugar
(sucrose), corn sugar (dextrose) and syrups such as molasses and
refiners syrups, and hereinafter all sugar-substrates are included
within the term "sugar". It has also been known to use dextrose
produced from say, wheat starch by acid or enzymatic hydrolysis.
There have been many attempts to replace, totally or
partially, the sugar content in sweet doughs because of the
relatively high price of sugar, especially at the present time and
no significant reversal of the upward trend is expected. However,
the available sugar also affects other characteristics of the bread
such as gas production, texture, grain, toasting time and crust
colour. Of particular importance is the gas production rate since,
as stated, if this is not sufficient, bread having the desired
characteristics, especially as regards toastability, cannot be
produced with the time limitations imposed by the baking processes
most widely used in North America. In fact, this is the major
factor which dictates that the available sugar level must be over
2% since below that level the yeast is not able to function
efficiently and bring about the required gas production rate.
Finding a substitute which will successfully fulfil all the
functions presently provided by the available sugar is far from
easy and has not as yet been successfully accomplished.
In some countries, dairy products having a significant
lactose content are included as a protein supplement in such dough
formulations to produce yeast goods such as the so-called "enrichea
breads". Refer, for example, to U.S. Patent No. 3,888,996 which
discusses generally the use of non-fat milk solids (NFDM) and whey
solids in baking processes. In Canada, especially, where enriched
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breads constitute by far the major portion of the bread market,
enriched breads must contain an approved dairy produc-t and in
particular NFDM, which contains about ~5% lactose, or whey powder,
which con-tains about 75~ lactose; (refer Section 13.022 Food &
Drug Act and Regulations). Also, lactose, both per se and as a
component of whey, has been used in the production of flavouring
material useful for imparting desirable flavouring and aromatic
characteristics to leavened bakery products, refer, for example, to
U.S. Patent ~o. 3,102,033.
Lactose is a disaccharide of low sweetness value and in
fact, in its usual (natural) form, is non-fermentable i.e. is not
metabolized by baker's yeast. Consequently, as in the above cases
for example, it passes through a baking process largely unaltered,
adding little to the bread apart from carbohydrate bulk and a
limited amount of colour to the crust and a slight improvement in
eating qualities of the baked bread. In addition, it is known that
lactose may be enzymatically hydrolyzed to yield equal amounts of
the simple sugars, glucose and galactose, which are fermentable by
baker's yeast. In fact, the enzyme lactase has been proposed to
convert (moderately non-sweet) lactose to the soluble simple sugars
referred to above to provide an increased degree of sweetness to,
and also reduce the lactose content of, various dairy products such
as whole milk and processed cheese and, in U.S. Patent ~o.
3,466,176, to provide a synthetic bread flavour additive. In that
patent, lactose in discrete whey is hydrolysed with the lactose
enzyme~ -galactocidase to produce galactose and glucose, yeas-t is
then introduced and the mixture fermented. The resulting product
is, in effect, a flavour enhancer for the described and claimed
synthetic bread "yeasty" flavour product. The use of whey is quite
optional, the same effect being obtained if glucose and/or
galactose p se are used as the growth medium for the yeast. The
hydrolysis of the whey and the subsequent yeast fermentation being
the hydrolysis products as substrate are totally completed prior to
its incorporation into the bread flavour product and obviously,
prior to the use of the latter product in the dough formulations
and baking processes.
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An object of the present invention is to provide a novel
dough formulation for producing yeast goods wherein a significant
proportion of the expensive sugar substrate included in the
formulation as a growth medium for the yeast during its gas
production may be eliminated.
A further object of the present invention is to provide a
baking process for producing yeast goods in which a significant
proportion of the required sugar content is replaced by an ln situ
simple sugar producing component.
Summary of Invention
It has now been realized, and this forms the basis of the
present invention, that the lactose present in yeast goods dough
formulations can be utilized to produce, in situ, simple sugars
fermentable by baker's yeast and as a consequence, the amount of
expensive simple sugars generally added to such formulations can be
significantly reduced resulting in great economic advantage.
For example, in Canada, the production of enriched white
bread by a bulk fermentation procedure generally utilizes a dough
formulation containing 4% sugar and 4% whey powder. The addition
of a minor "effective amount" of lactase to the formulation allows
the sugar content to be reduced to about 2% - i.e. a 50~ reduction
- without loss of gas production and the resulting bread quality,
as judged by crust colour, load volume, grain texture and toasting
time, were equal to the standard product: the bread produced was
actually considered marginally superior in eating qualities to the
standard product.
Moreover, further bread ~uality parameter(s) which are
usually adversely affected by a low sugar content are crumb
softness and rate of firming or staling. It was found that bread
produced using the present invention was undistinguishable as far
as those parameters are concerned with the product produced using
the usual formulation having the significantly higher sugar
content.
The present invention is quite versatile and can be used
to advantage with bulk fermentation, sponge and dough or straight
dough baking processes.
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Detailed Statement of Invention
According to the present invention, in a formulation for
producing yeast goods where flour, water, sugar and a fat-source
material are augmented with a lactose-containing dairy product, the
improvement comprising including in said formulation an effective
amount of a lactase enzyme thereby allowing a reduction in the
sugar content corresponding or equivalent to the amount of glucose
and galactose obtainable by the enzymatic hydrolysis of the lactose
by the lactase.
In another aspect, the present invention provides a
process for making yeast leavened bakery products wherein a bread
dough is formed by mixing a dough formulation including flour,
water, sugar, a fat-source material and a lactose-containing dairy
product and thereafter the dough is proofed and baked to form the
product, the improvement comprising including in said dough an
effective amount of lactase and reducing the amount of sugar in the
formulation by an amount corresponding to the amount of glucose and
galactose obtainable by the enzymatic hydrolysis in the baking
process of the lactose by the lactase.
It should be emphasized that in most instances, the
lactose-containing dairy product will normally already be included
in the dough formulation and consequently a significant reduction
in sugar addition is obtained solely by adding a very minor amount
of lactase and with substantially no adverse effects on product
desirable characteristics. However, the lactase may be prior
combined with the lactose-containing dairy product prior to its
incorporation into the dough formulation to form a baking
additive.
In a further aspect therefore the present invention
provides a dry baking additive for part replacement of sugar in a
dough formulation containing sugar, a fat-source and yeast
comprising a lactose-containing dairy product and an effective
amount of lactase.
It is preferred that the lactose-containing dairy product
is whey. ~owever, NFDM may be used but because of the relatively
low lactose content and the fact that the amount of ~FDM included
in dough formulations is less than the corresponding amount of whey
added, the actual amount of lactose in the formulation then
available for conversion to baker's yeast-fermentable simple sugars
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is relatively low and consequently, the amount of sugar which may
be replaced is correspondingly lower.
As a fat-source, generally shortening or lard, will
usually be present in the formulations used in the present
invention. In ins-tances where such fats are not used, for example,
in the production of Italian bread the normal practice is to omit
NFDM and/or whey also and consequently, the advantages of the
present invention cannot be achieved.
In this specifica-tion the term "effective amount" means
an amount of a lactase enzyme of a predetermined activity
sufficient to convert a major portion of the lactose in the
lactose-containing dairy product to the simple sugars, glucose and
galactose, which are fermentable by baker's yeast It is believed
that between 60% and 70% of the lactose in the lactose-containing
dairy product is convertible to glucose and galactose, and hence
becorne available to the yeast, during the baking process. it is
preferred that the formulation includes an amount of
lactose-containing dairy product such that the formulation
comprises from 2~ to 4~ by weight of lactose.
Present indications are that the maximum lactase enzyme
activity the lactase need have is equivalent to about 0.5~ by
weight, based on the lactose content of the formulation, of a
fungal lactase obtained from aspergillus Orygae and having an
activity of about 14,000 units/gram. However, from a practical
viewpoint, levels up to about 1% by weight of the fungal enzyme
referred to above, based on the amount of lactose in -the
formulation may be used to take into account expected variations
in stated enzyme activities, actual lactose content, etc.
Moreover levels as low as 0.3% by weight, based on the lactose in
the formulation (equivalent to about 1.4 grams/lb. of lactose in
the formulation~ has been found to work satisfactorily The
overall preferred range is from 0.25 to 0.5% by weight, based on
the weight of lactose in the formulation of the fungal enzyme
referred to above or a lactase having an equivalent lactase
en~ymatic activity.
The present invention will be further described with
reference to, but not limited by, the following specific examples.
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Example I
An enriched bread was produced via a zero bulk
fermentation procedure using the following formulations:
COMMERCIAL FORMULA: ENRICHED WHITE BREAD
FORMULASTANDARDSTANDARD WITH INVENTION
REDUCED SUGAR
E~RICHED WHITE
FLOUR 100 100 100
SUGAR 4 2 2
SHORTENING 3 3 3
SALT 2 2 2
WHEY POWDER 4 4 4
YEAST 3.25 3.25 3.25
EMULSIFIER0.25 0.25 0.25
WATER 65 65 65
LACTASE - - 6.8
All values are in lbs. except * which is in grams.
ATMUL 500 obtained from the Atlas Chemical Company
Food grade fungal lactase obtained from Aspergillus Oryzae and
sold under the trade mark TAKAMINE by the En~yme Products Division
of Miles Laboratories, Inc. having an activity of 14,000
units/gram.
The specific processing conditions were as follows:
Dough Mixing: Two (2) minutes at slow speed and thirteen (13)
minutes at high speed using a Champion Horizontal mixer: the dough
was at a temperature of 81F exiting the mixer:
Floor Time: Ten (10) minutes rest prior to transference to divider
hopper;
Dough scaled: At twenty-seven (27) ounces (for a twenty-four (24)
ounce loaf baked weight) - single pocket dough divider and conical
rounder;
Intermediate Proof: Ten (10) minutes in automatic 140 pocket
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~ travelling proofer with controlled temperature and humidity;
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Proofed: Eighty-five (85) minutes at a temperature of 115F and
85% relative humidity in an automatic two rack proofer;
Baking: Thirty (30) minutes at a temperature 400F in a six-shelf
revolving oven.
A major feature of the present invention is that CO2
gas production is not adversely affected despite the reduced
formulation sugar levels. The gas production during proofing in
the above process was therefore determined the results being as
follows:
Gas Production Formulation
(m.m. Pressure) Standard Standard Invention
(4% sugar) (2~ sugar) (2% sugar ~ lactase)
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30 (mins.) 110 100 126
213 200 240
286 250 323
120 363 300 400
150 436 365 466
180 511 420 510
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As the above results clearly illustrate, the CO2 gas
production during the make-up process is not significantly affected
when fully 50% of the normally added sugar content in the standard
dough formulation is eliminated and lactase is used in the
formulation as taught by the present invention. In effect, that
sugar content is replaced by the lactose/lactase in situ simple
sugar producing system, the sugar products of which are utilizable
by the yeast.
The baked bread products were subjected to quantitative
tests as follows:
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Formulation
Standard Standard Invention
(4% sugar) (2% sugar) (2% sugar & lactase)
Pan Proofed (mins.) 85 85 85
Proofed/weight (cm) 12.7 12.0 13.9
Loaf Volume (cc/gm) 5.6 5.2 6.0
Crumb Softness*
Gms force/lOmm
After 24 hours 11.6 14.4 10.3
After 96 hours 18.0 24.4 18.3
*Evaluated using a Baker Compressimeter
The above results clearly demonstrate that the bread
obtained according to the present invention is at least equal in
quality, if not superior in certain respects, to the product
produced using the standard formulation.
Also, evaluations of crust colour, grain, texture and
toasting ~ime of the standard bread and bread produced according to
the present invention were essentially the same.
Moreover, the products of the invention were considered
marginally superior in eating qualities.
In times of high sugar prices, which occurs quite
frequently, the present invention also allows a reduction in the
amount of sugar which must be used and a significant saving
results.
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EXAMPLE II
An enriched bread was produced by straight dough
procedure, using the following formulation.
LABORATORY FORMULA ENRICHED WHITE BREAD
STANDARD STANDARD WITH
REDUCED SUGAR INVENTION
Enriched white
flour 400 400 400
Liquid Glucose
syrup 20 10 10
Shortening 12 12 12
Salt 8 8 8
Whey Powder 16 16 16
Yeast 12 12 12
Emulsifier (1)
Water 260 260 260
Lactase (2) --- --- 210*
All weights are in,grams except * which is in millgrams.
1) Atmul 500 obtained rom the Atlas Chemical Company
2) Food grade fungal lactase obtained from Aspergillus Oryzae and
sold under the trade mark SUM~LACT LL 5000, assaying 14000 LU/gram,
by Miles Laboratories Ltd.
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The specific processing conditions were as follows:
DOUGH MIXING
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One half (~2) minute at low speed and two and one half
(2l~2) minutes are Second speed using a Hobart Mixer (5 qt) equipped
with -the McDuffy Bowl. The dough temperature was 82F when mixed.
FERMENTATION
One (1) hour in a tempera-ture controlled fermentation
cabinet maintained at 86F.
PUNCH
The doughs were de-gassed scaled to 540 grams per loaf,
rounded and replaced in fermentation vessels for a further one-half
(~) hour.
MAKE-UP
Doughs were sheeted through the National Moulder and
Sheeter and made up according to the procedure of the American
Association of Cereal Chemsit and panned.
PROOFED
Foe one hour (1) at 115F ana 85 R.H. in a temperature,
humidity controlled cabinet.
BAKING
Thirt~ (30) minutes at 400F in a six shelf revolving
tray oven.
A major feature of the present invention is that CO2
gas production is not adversely affected despite reduced
formulation sugar levels. The gas production during fermentation
and proofing in the above process was determined, the results being
as follows:
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FORMULATION
GAS PRODUCTION INVEMTIO~I
MM PRES _RE STAMDARD STANDARD 2~2% GLUCOSE
5~ GLUCOSE 2~2% GLUCOSE LACTASE
30 minutes 110 95 100
60 minutes 195 170 180
90 minutes 270 235 265
120 minutes 345 315 330
150 minutes 435 390 420
180 minutes 505 455 490
210 minutes 550 495 525
240 minutes 580 535 550
270 minutes 600 555 630
300 minutes 620 575 710
As the above results clearly illustrate, the CO2 gas
production during the dough make-up process is not significantly
affected when fully 50~ of the normally aclded sugar in the standard
formula is eliminated and lactase is used in the formulation
according to the present ;nvention. In effect, that sugar content
is replaced by the lactose/lactase simple sugar producing system
whicn in situ produces sugar products which are utilizable by the
yeast. It can readily be appreciated, especially where the
addition of milk solids containing lactose is mandatory or
otherwise required, that the present invention allows for
significant savings.
The baked products were subjected to the following tests
and observations:
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FORMULATION
INVENTION
STANDARD STANDARD 2~2% GLUCOSE
5% GLUCOSE 2~2% GLUCOSE + LACTASE
PROOF TIME (MIN) 60 60 60
PROOF HEIGHT (CM) 12.7 12.3 13.3
VOLUME (CC/GM) 5.2 5.1 5.5
CRUST COLOUR medium medium - medium +
The above results clearly demonstrate that the bread
obtained according to the present invention is equal to or better
than standard with respect to gas production and retention thereof
in the dough during fermentation, proofing and baking. Moreover,
the residual sugars resulting from the in situ production of
glucose/galactose from lactose was evidenced by the more enhanced
colour of the crust of the baked bread from the formulation
according to the present invention.
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