Note: Descriptions are shown in the official language in which they were submitted.
~2~
BACKGROUND_OF_THE INVENTION
1. Field of the Invention:
This invention relates to the production of protein-
enriched breads and other related baked products. More ~pecific-
ally, it relates to protein-enriched baked products which are
an excellent dietary source of protein.
2. Description of the Prior Art:
In recent years there has been a great interest in
the protein content of food products. This has become an
important priority of the food industry because of the inadequate
levels of dietary protein throughout the world and because of
consumer desire for high-protein low-caloric foods. Of course,
food products which are already familiar and have gained wide
public acceptance are especially valuable for use in protein
enrichment programmes.
Baked products, such as bread, rolls, buns,sweet
rolls, etc., have long been a basic staple of our diet and the
inherent functional versatility allows baked products to be a
convenient carrier for many nutrients.
.
Many attempts have already been made to improve the
protein content of baked products. For instance, it has been
known for a number of years that wheat protein is relatively
deficient in certain amino acids, such as L-lysine and that this
deficiency can be substantially overcome by combining soy flour
as non-wheat protein source with wheat flour. Various such
formulations including soy flour are described in U.S. Patent
3,756,832 issued September 4, 19730
3~ Soy flour supplements have been of great interest
because of their availability and low cost. However, they have
not been without their problems and U.S. Patent 3,679,433,
issued July 25, 1972 describes the use of additional
additives which attempt to overcome the deleterious effects
of soy Elour in dough formulations.
Canadian Government Regulations define an excellent
dietary source of protein as one having a protein rating
of 40 or more. Irhis pro-tein rating is equal to the protein
efficiency ratio (PER) times the grams of proteln in the
recommended daily intake (RDI). This means that in order
to obtain a bread meeting the required protein rating of
40 or more, the PER must be at least 1.65 and there must
be a crude protein content of at least 166 by weight.
It has been found -that a bread made with the sole sup-
plementation of soy flour, while overcoming the L-lysine
deficiency, produced a bread with a PER of only 1.~1 and
a protein rating of only 30. Thus, the addition of soy
flour alone falls far short of providing a commercially
acceptable bread which can be considered to be an excel-
lent dietary source of protein.
It is, therefore, the object of the present invention
to produce baked products which will be superior to those
made with only soy flour supplementation and will provide
a protein rating of 40 or more.
SUMMARY OF THE INVENTION
Thus, the present invention relates to the production
of baked products from wheat flour wherein a dough formul-
ation is mixed, fermented, kneaded, shaped and baked.
According to the inventive feature, there is added to the
dough formulation a blend of protein sources containing
yeast protein, soy flour or concentrate and pea concen~
trate, at least S0~ of said blen~ containing soy flour or
concentrate and said blend being present in an amount of
10 to 40 parts hy weight per 100 parts of wheat flour and
~elected to complement the essential amino acid pattern of
wheat ~lour whereby a baked product is obtained having a crude
protein content of at least 16% by weight, a protein efficiency
ratio of at least 1.65, a protein rating of at least 40 and an
essential amino acid pattern which closely approximates that
of egg protein without addition of synthetic amino acids.
This provides an essential amino acid pattern which
closely approximates that of egg protein without addition of
synthetic amino acids. .-
Although soy flour and soy concentrate can be used as a
part of this blend, they are not sufficient in themselves.
Moreover, other protein sources can be used in place of soy
products while achieving equally good results. ~nother use-
ful component of the blend is yeast protein. It is also a
preferred feature of this invention that the protein sources
be derived from vegetable or grain sources and that none be
derived from animal sources.
In selecting the speci~ic protein sources and their pro-
portions to achieve the results according to this invention,
these are selected such that the supplement when blended with
wheat flour will provide an essential amino acid pattern which
closely approximates that of egg protein. The literature has
shown that there are maximum levels of protein supplementation
which will still maintain a commercially acceptable bread loaf
and this has been one of the problems with the use of soy
flour. In accordance with this invention it has been deter-
mined that it is quite possible to stay within the limits of
total protein supplementation which will maintain a commer-
cially acceptable loaf but that by a proper selection of a
protein source blend the desired level of protein availability
can be obtained in the baked product while staying within the
maximum levels of permitted total supplementation.
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~ i
Partlclllarly preferred proteLn sources meeting these
requirements are blends of at least three protein sources
selected from Torula yeast, soy flour, soy concentrate, pea
concentrate and triticale. It is also particu]arly preferred
that no more than 75% of the total protein supplement consists
of a single protein source, and that at least 50% of the total
protein supplement consists of soy flour and/or soy
concentrate. Typical quantities of the protein sources per
100 parts of wheat flour are about 3 to 25 parts yeast protein,
up to 30 parts soy flour and/or soy concentrate and up to
15 parts pea concentrate. Small additions of triticale
are useful for raising the level of methionine.
'~ DESCRIPTION OF THE PREFERRED EMBODIMENTS
Because of what was already known about soy flour as a
supplement, this was used as the standard supplement to determine
the opt`imum level of supplementation. A variety of supplement
additions ranging from 2.5 to 25% by weight based on flour were
used with sodium stearoyl lactylate and two levels of gluten
being tested to determine their effectiveness in maintaining
loafvolume during supplementation. The first level of gluten
was added to provide a GOnStant percentage of gluten in the dry
ingredients at all levels of supplementation, while the second
level of gluten was designed to augment the first gluten level
by a constant percentage of the supplement.
The basic-formulation is shown in Table 1 below.
:~ .
.
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TABI.E I
_ORMUL~_FOR TEST BAKING
-- .
Weight %
Ingredient Grams Flour 8asis
. .,
Flour 700 100.0
Water 469 - 567 67 - 81 (Variable)
Supplement
~- ~Soy Flour) 17.5 - 175 2.5 - 25 "
Vital Gluten 1.75 - 43.75 0.25 - 6.25
~ Sodium Stearoyl
Lactylate (S.S.L.) 2.625 0.375
Yeast 21.0 3.0
Salt 14.0 2.0
Sugar 42.0 6.0
Shortening 21.0 3.0
Yeast Food 1.75 0.25
.
A Brabender Farinograph was used to determine water
absorption, mixing time and mixing tolerance at all levels of
supplemeatation. The physical parameters examined were loaf
volume, crumb lightness (Hunter colour-difference meter-"L"
value), and grain appearance. A maximum deviation of 15% from
the standard white bread volume was permitted for a commercially
acceptable loaf.
The bread was baked using the sponge and dough method
and the mixing times, tolerances and farinograph absorptions are
shown in Table II below.
~
: TABLE II
EFFECTS OF SUPPLEMENTA_ION
_ .
Test Mixing Time Tolerance Ab~orption
(min) (min)(%H20)
,._
~- 10 Control 5~ 12 68.6
Control + 2.5% Supplement 5~ 14 69.2
" + 5.0% " 6~ 15 70.0
~`~ " + 10.0~ " 7~ 17 72.2
` " + 15.0% " 7~ 15~ 74.1
.~: " + 20.0% " 7~ 13~ 75.7
:" -~ 25.0% " 8 16~ 76.4
~ Control + 2.5% " + SSL(0.3i5%) 9 18~ 68.2
-~ " + 5.0% " " 7~ 18~ 70.0
.~ " + 10.0% " " 8~ 18 70.8
`~ 20 " + 15.0% " " 8~ 16~ 72.7
~:~ " + 20.0% " " ` 9 16 75.0
,. " + 25.0% " " 9 16~ 76.6
~; Control + 2.5% " + Gluten I 5~ 12~ 71.4
" + 5.0% " " 6~ 13~ 72.0
" + 10.0% " " 8~ 17 74.0
,~ " + 15.0% " " 8~ 16 76.5
+ 20.0% " " 9 15 78.6
~; " + 25.0% " " 9 16 79.5
Control + 2.5% " + Gluten Il 5~ 9 68.1
" + 5.0% " " 5~ 10~ 69.9
" + 10.0% " " 8 13 72.1
" + 15.0% " " 8~ 16 76.9
" + 20.0% " " 9~ 15~ 79.8
" + 25.0% " " 10 16~ 81.0
~ 6 --
. .
It will be seen that addition oE SSL and gluten
increased both the mixing time and absorption. In general, loaf
volume decreased as level of supplement increased and both SSL -
and gluten had positive effects on the maintenance oE loaf volume.
Acceptable loaves were obtained at a level of 25~ supplementation
when either SSL or gluten was added.
sased on the above background information, a complete
trial was carried out using a supplementation level oE ~0% with
soy flour as the sole supplement. A second trial was conducted
using a mixture of soy flour and other protein sources and a
third trial was run using other protein sources in the absence
of any soy flour. The details of these three formulatlons are
given in Table III (all quantities being expressed ln pounds).
The breads were prepared by the sponge and dough
system and the finished breads were freezed-dried to a level of
2% moisture prior to PER and amino a~id analysis. A11 PER values
were adjusted to an ANRC casein value of 2.5.
The results obtained are shown in Table IV.
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The above trials showed that a very acceptable alter-
nate to soy can be formulated using a complementary blend of
other protein sources,but all of the formu~ations shown in
Table IV showed a protein rating well below the recommended
level of 40 or more. This was found, even though the essential
amino acid pattern did come quite alose to that of egg protein.
There will now be described a series of formulations
mleeting the requirements of the present invention.
EXAMPLES 1 to 6
Bread according to the invention was made by the sponge
and dough teahnique from the formulations of Table V below (all
quantities being expressed in pounds):
~.
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o ,~ IA ~ O ~ V
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-- 11 --
:......... ~ -,- `: '
The process conditions are as follows:
Sponge FermentationTime: 4-6 hours
Sponge Temperature O
tin ferment) 70_75 F
Sponge Temperature
(out of ferment) : 80-90 F
The dough was baked at 425 for 25 minutes and
the baked bread weighed approximately ~50 grams with a volume
of approximately 1800 cc. All the breads tested had an accept-
able colour, flavour and aroma and generally had a loaf volume
of about 12 to 15% less than conventional white bread.
For protein analysis, the finished breads were
freeze-dried to a level of 2~ moisture and then subjected to
PER and amino acid analysis. All analysis were carried out by
Nutrition International oE New Brunswick, N.J., in accordance
with A.O.A.C. methods. A11 PER values were adjusted to an ANRC
casein value of 2.5.
2a The results obtaïned are set out in Table VI.
In the above Table, Examples 1, 2 and 3 contained
25% supplement hased on wheat flour and Examples ~, 5 and 6
contained 30~ by weight supplement based on wheat flour.
Example 1 with 25~ supplement and Examples 4 , 5 and
6 with 30~ supplement all showed excellent protein ratings
well above the desired minimum of 40, while Example 3 with
25% supplement was just over the minimum protein rating and
Example 2 with 25~ supplement fell slightly below the minimum
rating.
- 12 -
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-- 13 --
