Note: Descriptions are shown in the official language in which they were submitted.
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LOW SALT FOOD WITH IMPROVED TASTE
Field of the invention
The present invention relates to the use of a yeast extract for the
improvement of
taste in cereal products. In particular, it relates to the improvement of
taste of low-
sodium cereal products with reduced sodium content.
Background of the invention
The use of sodium chloride, has long been suspected as a cause of health
problems, particularly hypertension. It is very difficult to limit salt intake
to very low levels
because processed foods, takeaway foods and restaurant-prepared foods
typically
contain large amounts of salt. At the same time, there is a trend with many
food
processors to reduce the amount of sodium in processed food, in particular in
cereal
products because they constitute a large part of our daily diet. For example,
bread
contains a substantial amount of sodium chloride and is consumed every day. To
some
degree the problem of high salt levels in foods, such as bread, could be
reduced by
simply lowering the level of salt added to the food, however this leads to a
reduced salt
perception and is therefore undesired. Another disadvantage of salt
substitutes, such as
potassium chloride, is that they impart an "off" flavor to food. As a
consequence, it is
necessary to use additives to mask the off-flavor of the salt substitutes.
US 4297375 discloses the use of an autolyzed yeast to reduce bitterness in
foods caused by the presence of potassium chloride-containing salt
substitutes.
EP0103994 describes a sodium chloride substitute flavoring system which
comprises autolyzed yeast and ammonium chloride. The system improves the
saltiness
of foods, reduces the bitterness of sodium chloride substitutes and is
suitable for use in
a sodium chloride substitute system for savoury applications.
WO 2005/087013 describes the use of a dry taste enhancing agent for cereal
products which taste-enhancing agent comprises a yeast extract and acid
fermented
flour.
A problem associated with the yeast extracts as generally described in the
prior
art is that they can cause the food to which they are added to get a bouillon-
like, brothy
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taste or after taste associated with yeast (yeasty taste and/or odour). This
problem is
especially evident in beverages and in non-savoury food.
Detailed description of the invention
The present invention relates to the use of a yeast extract for preparing a
cereal
product with reduced sodium content compared to a corresponding conventional
cereal
product, wherein the yeast extract comprises at least 30% w/w 5'-
ribonucleotides on the
basis of sodium chloride free dry matter. This may lead to a reduced sodium,
low-
sodium, a very low sodium or a sodium-free cereal product.
There are several advantages of using such yeast extract for preparing cereal
products with reduced sodium content. One advantage is that bitter off-tastes,
for
instance from salt substitutes such as potassium chloride, are masked if a
yeast extract
comprising at least 30% w/w 5'-ribonucleotides on the basis of sodium chloride
free dry
matter is added to the flour for low-sodium cereal products.
Another advantage is that the yeast extract effects a neutral taste
enhancement,
i.e. taste enhancement without the introduction of a brothy, bouillon note or
yeasty note.
Yet another advantage is that by using a yeast extract which comprises at
least
30% w/w 5'-ribonucleotides on the basis of sodium chloride free dry matter the
salt
perception is enhanced. This is of course very advantageous in reduced-sodium
food
applications. As a result, less sodium and less sodium replacers or taste
enhancers are
necessary to improve the taste of a reduced-sodium cereal product.
Another advantage is that there is no requirement to label cereal products
which
have been prepared according to the invention as containing chemical
additives.
The term "cereal product with reduced sodium" refers to a cereal product
wherein
the amount of sodium in the product is less than the amount of sodium
conventionally
present in the corresponding conventional cereal product. Preferably the
cereal product
will comprise at least 25% w/w less sodium than conventionally present in the
corresponding conventional cereal product. Said cereal product with reduced
amount of
sodium may comprise at least 25% w/w, 30% w/w, 35% w/w or 40% w/w less sodium,
more preferably at least 45% w/w, 50% w/w, 55% w/w or 60% w/w less sodium than
conventionally present in the corresponding conventional cereal product. The
cereal
product with reduced sodium prepared according to the method of the first
aspect may
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comprise up to -100% w/w less sodium than conventionally present in the
corresponding conventional cereal product.
The amount of sodium conventionally present in the cereal product is the
amount
present when the cereal product has not been altered, processed or formulated
in order
to reduce its sodium content and will depend on the type of cereal product,
hence the
reference to a 'corresponding' cereal product. Those skilled in the art know
the amount
of sodium which is conventionally present in a cereal product depending on the
type of
cereal product.
According to the invention, a yeast extract is used which comprises at least
30%
w/w 5'-ribonucleotides, preferably at least 34% w/w, 38% w/w, 40% w/w or 42%
w/w,
more preferably at least 44% w/w, 46% w/w, 48% w/w or at least 50% w/w 5'-
ribonucleotides on the basis of sodium chloride free dry matter.
In the context of the present invention, the phrase "5'-ribonucleotides"
refers to
the total amount of 5'-monophosphate ribonucleotides formed during RNA
degradation,
viz. 5'-monophosphate guanine (5'-GMP), 5'-monophosphate uracil (5'-UMP), 5'-
monophosphate cytosine (5'-CMP), 5'-monophosphate adenine (5'-AMP), where 5'-
AMP
may be partially or completely converted into 5'-monophosphate inosine (5'-
IMP). For
example, in a yeast extract which comprises 30% w/w 5'-ribonucleotides on the
basis of
sodium chloride free dry matter, the total amount of 5'-GMP, 5'-UMP, 5'-CMP,
5'-AMP
and 5'-IMP is 30% w/w on the basis of sodium chloride free dry matter.
In a preferred embodiment, a yeast extract is used wherein the total amount of
5'-GMP plus 5'-IMP is at least 15% w/w, preferably at least 17% w/w, 19% w/w,
20%
w/w or 21 % w/w, more preferably at least 22% w/w, 23% w/w, 24% w/w or 25%
w/w, on
the basis of sodium chloride free dry matter. Due to the constitution of RNA,
from which
the 5'-ribonucleotides arise, 5'-GMP and 5'-IMP will always be present in
approximately
equal amounts in this embodiment.
In the context of the present invention, weight percentage calculations of the
5'-
ribonucleotides are based on the disodium salt heptahydrate thereof unless
otherwise
specified. All percentages are calculated on sodium chloride free dry matter
(sfdm). In
the present invention, the phrase 'sodium chloride free dry matter (sfdm)'
refers to the
fact that for the calculation of the weight percentage the weight of any
sodium chloride
present in the yeast extract is excluded from the composition. The measurement
of
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sodium chloride in the yeast extract and the above-mentioned calculation can
be
performed by methods known to those skilled in the art.
The yeast extract may be prepared by any method which yields a yeast extract
which comprises at least 30% w/w 5'-ribonucleotides (sfdm).
In one embodiment of the invention, the yeast extract is obtained by
hydrolysis.
Hydrolytic yeast extracts are concentrates of the soluble material obtained
from yeast after
disruption of the cells, digestion (lysis) and addition of exogenous enzymes
such as
proteases and/or peptidases and especially nucleases, such as 5'-
phosphodiesterase and
optionally 5'-adenylic deaminase, to the yeast suspension during lysis. The
native yeast
enzymes are generally inactivated prior to the lysis. During this process 5'-
GMP, 5'-UMP,
5'-CMP and 5'-AMP may be formed. When adenylic deaminase is added to the
mixture, 5'-
AMP is transformed into 5'-IMP. Methods to produce hydrolytic yeast extracts
are known in
the art, see for example W088/05267.
In another embodiment, the yeast extract is obtained by autolysis, for
instance as
described in W02005/067734.
Preferably, the 5'-ribonucleotides of the yeast extract are produced in the
autolytic or hydrolytic extraction process, i.e. in a natural process, as
described in the
previous paragraph. However, the skilled person will understand that a yeast
extract
which comprises at least 30% w/w 5'-ribonucleotides (sfdm) may be obtained by
adding
isolated or chemically synthesized 5'-ribonucleotides to a yeast extract which
contains
less than 30% w/w 5'-ribonucleotides. The use of these types of yeast extract
is also
encompassed in the present invention, but is less preferred. It has the
disadvantage that
food products prepared with such yeast extracts will have to be labeled as
containing
chemical additives.
With the methods mentioned above also yeast extracts may be produced which do
not fulfil the requirements of the first aspect of the invention. However the
yeast extracts
comprising the proper amount of 5'-ribonucleotides may be selected by
measuring the
amounts thereof using methods known to those skilled in the art and by
selecting those
yeast extracts which comprises at least 30% w/w 5'-ribonucleotides (sfdm).
According to the invention, yeast extracts may be used which comprise up to
90% w/w or even 100% w/w 5'-ribonucleotides on the basis of sodium chloride
free dry
matter, although such compositions are not yeast extracts as intended by the
Food
Chemical Codex.
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In another aspect, the present invention relates to a method for preparing a
cereal product with reduced sodium content compared to a corresponding
conventional
cereal product, from a flour-based dough, wherein the method comprises
replacing part
5 of the sodium which is conventionally present in the dough by a yeast
extract, wherein
the yeast extract comprises at least 30% w/w 5'-ribonucleotides (sfdm). In a
preferred
embodiment, the reduced-sodium cereal product is prepared using a yeast
extract which
comprises at least 15% w/w of 5'-GMP plus 5'-IMP on the basis of sodium
chloride free
dry matter. By this method a reduced-sodium cereal product, or the
intermediate
product, may be obtained which is fully acceptable to the person skilled in
the art. For
example, a bread with reduced sodium content compared to a corresponding
conventional bread may be obtained which has good volume, crumb structure and
softness.
The yeast extracts used in the context of the invention may be obtained from
any
yeast. Suitable yeast strains which may be used belong to the genera
Saccharomyces,
Kluyveromyces and Candida. Yeast strains belonging to the genus Saccharomyces,
for
example to the species Saccharomyces cerevisiae, are preferred.
Methods for preparing a baked cereal product are known in the art, e.g. from
Baking Science & Technology (1988, 3rd edition) ed. P.J. Pyler, Sosland
Publishing Co,
Kansas City, MS, USA and typically include preparing, kneading, fermentation
and
baking of a dough. Baked cereal products are typically prepared from a flour-
based
dough and sodium chloride is invariably one of the constituents of the dough.
Suitable
examples of cereal and in particular of baked cereal products include all
types of bread,
such as white bread, sliced bread, soda bread, brown bread, wholemeal bread,
malt
bread, granary bread, rye bread, corn bread, pitta bread, baquettes, French
sticks,
bagels, rolls, croissants, pan bread; all types of cakes and cookies, such as
muffins,
scones, pound cake, sponge cake, pancake, brownies, biscuits, crisps, short
bread,
crackers, fruit cake; and also including pappadums, chapatti, nan, paratta,
polenta, taco,
tortilla, corn flakes, croutons and any type of pasta.
Therefore, in one embodiment of the present invention, a yeast extract which
comprises at least 30% w/w 5'-ribonucleotides (sfdm) is used to prepare a
reduced-sodium
baked cereal product, i.e. a baked cereal product which is produced form a
dough which
comprises less sodium than conventionally used in doughs for baked cereal
products. In a
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preferred embodiment, a yeast extract comprising at least 15% w/w 5'-GMP plus
5'-IMP is
used to prepare a reduced-sodium baked cereal product.
All or part of the sodium in the dough may be replaced by yeast extract which
comprises at least 30% w/w 5'-ribonucleotides or at least 15% w/w of 5'-GMP
plus 5'-
IMP (sfdm). Preferably, the dough used for preparing the cereal product
comprises at
least 25%, 30%, 35% or 40% w/w less sodium, more preferably at least 45%, 50%,
55%
or 60% w/w less sodium than conventionally used. The amount of sodium
conventionally
present in a cereal product is the amount present when the cereal product has
not been
altered, processed or formulated in order to reduce its sodium content and
will depend
on the type of cereal product, hence the reference to a 'corresponding' cereal
product.
Those skilled in the art know the amount of sodium which is conventionally
present in a
certain type of cereal product.The sodium is typically present in the form of
sodium
chloride (NaCI).
Therefore, in another aspect, the invention relates to a cereal product with
reduced
amounts of sodium in comparison to a corresponding conventional cereal
product,
prepared from a flour and sodium-containing dough which dough comprises (i)
less sodium
than the corresponding conventional cereal product and (ii) 0.01% to 2% w/w of
a yeast
extract which comprises at least 30% w/w 5'-ribonucleotides (sfdm). The
reduced-sodium
cereal product is prepared from a flour and sodium-containing dough which
dough
comprises (i) preferably at least 25%, 30%, 35% or 40% w/w less sodium, more
preferably
at least 45%, 50%, 55% or 60% w/w less sodium than the corresponding
conventional
cereal product and (ii) preferably 0.01 % to 2% w/w, more preferably 0.05% to
1% w/w of a
yeast extract which comprises at least 30% w/w 5'-ribonucleotides (sfdm).
Depending on
the amount of sodium left in the product and national legislation, such
reduced-sodium
products may also be referred to as low-sodium, very low sodium or sodium-free
cereal
products. In a preferred embodiment, the yeast extract is used to prepare a
reduced-
sodium bread product. In one embodiment, 0.01% to 2% w/w yeast extract on the
total
weight of flour is used. Preferably, 0.05% to 1% w/w yeast extract on the
total weight of
flour is used for preparing a reduced-sodium bread.
The yeast extract which comprises at least 30% w/w 5'- ribonucleotides or at
least
15% w/w of 5'-GMP plus 5'-IMP (sfdm) may be used in combination with other
salt
substitutes and salt taste enhancers known in the art, such as LiCI, LiBr,
KCI, NH4CI, other
ammonium salts, dipeptides and amino acids derivatives. Therefore, in another
aspect the
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invention relates to a blend suitable for preparing a reduced-sodium cereal
product. In one
embodiment, the blend comprises a yeast extract which comprises at least 30%
w/w 5'-
ribonucleotides (sfdm) in combination with KCI, and preferably NH4CI. Suitable
amounts are
30-70%, preferably 40-60%, more preferably 50-60% w/w KCI; 5-30%, preferably
10-20%,
more preferably 15-20% w/w NH4CI; and 5-35%, preferably 10-30%, more
preferably 12-
25% w/w of a yeast extract which comprises at least 30% w/w 5'-ribonucleotides
(sfdm).
Less than 1% w/w on flour weight, typically, 0.1 - 0.8 % w/w on flour weight
of such blends
is used for preparing reduced-sodium cereal products. A carrier may also be
included. If a
carrier is used, the carrier is preferably an oil, more preferably a vegetable
oil. Preferably,
0.1-1% w/w of the carrier is used. All the products and blends of the present
invention may
advantageously be used in a low-sodium, reduced-sodium or no-sodium diet or in
the
treatment of hypertension or cardiovascular disease.
EXAMPLES
Example 1
The effect of a 5'-ribonucleotide-rich yeast extract on the taste of a bread
with
reduced sodium content
In this example the effect of a 5'-ribonucleotide-rich yeast extract on the
taste of a bread
with reduced sodium is demonstrated.
Procedure:
Ingredients:
- 5'-ribonucleotide-rich yeast extract containing 20 %w/w 5'GMP + 5'IMP, 40
%w/w 5'-
ribonucleotides and < 1% sodium chloride on dry matter, from DSM Food
Specialties,
the Netherlands.
- Fungal a-amylase from DSM Food Specialties, the Netherlands.
- Hemi-cellulase from DSM Food Specialties, the Netherlands.
Bread dough was prepared according to the scheme presented in Table 1. In all
tests
including the reference 70 g compressed yeast (2% w/w based on total weight)
were
also present in the bread ingredients.
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Table 1: dough composition
Ingredient Reference Test 1 Test 2 Test 3 Test 4
Flour (g) 3500 3500 3500 3500 3500
Sodium chloride (g) 70 48 48 48 48
KCI (g) - - 9.6 9.6 -
NH4CI (g) - - 3.0 3.0 -
Ascorbic acid (mg) 140 140 140 140 140
Fungal alpha-amylase (mg) 10.5 10.5 10.5 10.5 10.5
Hemicellulase (mg) 52.5 52.5 52.5 52.5 52.5
Water (g) 1972 1972 1972 1972 1972
Yeast extract with 20% w/w
5'-GMP plus 5'-IMP (sfdm) - - - 3.5 3.5
(g)
The ingredients were mixed into a dough using a Kemper spiral mixer for 2
minutes at speed 1 followed by 6 minutes mixing at speed 2. Dough temperature
was 28
C. Bulk proof was 5 minutes at 34 C/85 % relative humidity. Next, dough pieces
of 875
g were rounded, proofed for 35 minutes at 34 C/85 % relative humidity.
Finally, dough
pieces were punched, moulded, panned, proofed for 75 minutes at 34 C/85 %
relative
humidity and baked for 20 minutes at 220 C.
Dough properties (Table 2) and the breads produced from the different doughs
were
evaluated. Taste was evaluated by an experienced taste panel and compared with
the
taste of the reference bread (Table 3). Special attention was paid if bouillon
notes could
be tasted in the bread which contained the yeast extract, because bouillon
notes are
normally associated with the application of yeast extract.
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Table 2: dough properties of the different tests
Dough attribute Reference Test 1 Test 2 Test 3 Test 4
Consistency 0 0 0 0 -1
Extensibility 0 1 1 1 -1
Development/body 1 0 0 1 1
Stickiness 0 0 0 0 1
Scores within -3 and 3, reference = 0, +/- 1 = minor deviation from reference,
fully acceptable, +/-2 = major
deviation from reference, in most cases not acceptable, +/- 3 = major
deviation, absolutely not acceptable.
From Table 2 it is clear that 30% salt reduction results in less developed and
more extensible dough. Addition of small quantities of KCI/NH4CI does not
really change
dough rheology. After addition of the 5'-ribonucleotide-rich yeast extract,
dough
development was similar to the reference, only extensibility was somewhat
increased.
This difference to the reference is fully acceptable to the skilled person.
After baking, no significant differences were seen in loaf volumes.
The dough properties of each test were comparable to that of the reference
dough. The final breads were evaluated on taste by a trained taste panel.
Results are
presented in Table 3.
Table 3
Taste attribute Reference Test 1 Test 2 Test 3 Test 4
Salt 100 40 70 90 65
Bitter No No Yes No No
Bouillon/yeasty
No No No No No
off-taste
The results in Table 3 clearly demonstrate that the salt perception in bread
having 30% less sodium chloride can be compensated almost completely with a
yeast
extract which comprises at least 15% w/w of 5'-GMP plus 5'-IMP (and thus at
least 30%
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w/w 5'-ribonucleotides (sfdm)). If such yeast extract is added to a dough
which also
comprises potassium chloride and ammonium chloride, the yeast extract will
also mask
the bitter off-taste introduced with the potassium chloride. The fact that no
bouillon-like
note was tasted in bread of Test 3 or 4 makes it clear that the background- or
bouillon
5 taste normally present in yeast extract is almost absent.
Example 2
The effect of the 5'-ribonucleotide concentration of yeast extract on the
taste of a
bread with reduced sodium content
This example was done to demonstrate the effect of the 5'-ribonucleotide
concentration
on taste of bread with reduced amount of sodium chloride.
Procedure:
Ingredients:
- 5'-ribonucleotide-rich yeast extract containing 20 % w/w 5'GMP + 5'IMP, 40 %
w/w 5'-
ribonucleotides and < 1% sodium chloride on dry matter, from DSM Food
Specialties,
the Netherlands.
- 5'-ribonucleotide containing yeast extract containing 11.2 %w/w 5'GMP +
5'IMP, 22.4%
w/w 5'-ribonucleotides and 20 % of sodium chloride on dry matter (DSM Food
Specialties). This is equivalent to14% w/w 5'GMP + 5'IMP and 28% w/w 5'-
ribonucleotides on sodium chloride free dry matter basis.
- Fungal alpha-amylase from DSM Food Specialties, the Netherlands.
- Hemi-cellulase from DSM Food Specialties, the Netherlands.
Both yeast extracts were dosed on 5'-ribonucleotide content.
Bread dough has been prepared according to the scheme presented in Table 4. In
all
tests including the reference 70 g compressed yeast (2% w/w based on total
weight)
were also present in the bread ingredients.
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Table 4: dough composition
Ingredient Reference Test 1 Test 2
Flour 3500 3500 3500 g
Sodium chloride 70 46.7* 48 g
KCI - 9.6 9.6 g
NH4CI - 3.0 3.0 g
Ascorbic acid 140 140 140 mg
Fungal alpha-amylase 10.5 10.5 10.5 mg
Hemi cellulase 52.5 52.5 52.5 mg
Water 1972 1972 1972 g
Yeast extract containing g
14% w/w 5'-GMP plus - 6.3 -
5'-IMP (sfdm)
Yeast extract containing g
20% w/w 5'-GMP plus - - 3.5
5'-IMP (sfdm)
* Compensated because of the sodium chloride content in this yeast extract
sample
The ingredients were mixed into a dough using a Kemper spiral mixer for 2
minutes at speed 1 followed by 6 minutes mixing at speed 2. Dough temperature
was 28
C. Bulk proof was 5 minutes at 34 C/85 % relative humidity. Next, dough pieces
of 875
g were rounded, proofed for 35 minutes at 34 C/85 % relative humidity.
Finally, dough
pieces were punched, moulded, panned, proofed for 75 minutes at 34 C/85 % RH
and
baked for 20 minutes at 220 C.
Dough properties (Table 5) and the breads produced from the different doughs
were evaluated. Taste was evaluated by an experienced taste panel and compared
with
the taste of the reference bread (Table 6). Special attention was paid if
bouillon notes
could be tasted in the bread enriched with the yeast extract, because bouillon
notes are
normally associated with the application of yeast extract.
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Table 5: dough properties of the different tests
Dough attribute Reference Test 1 Test 2
Consistency 0 1 -1
Extensibility 0 2 1
Development/body 1 2 1
Stickiness 1 2 0
Scores within -3 and 3, reference = 0, +/- 1 = minor deviation from reference,
fully acceptable, +/-2 = major
deviation from reference, in most cases not acceptable, +/- 3 = major
deviation, absolutely not acceptable.
The results demonstrate that the extensibility changed too much for the dough
containing the yeast extract which comprised 14% w/w 5'-GMP plus 5'-IMP. In
addition,
small differences were noticed on the consistency, dough development and
stickiness.
Especially, the difference in extensibility made the dough properties
unacceptable.
Addition of the yeast extract containing 20% w/w 5'-GMP plus 5'-IMP resulted
only in
small differences on the consistency, extensibility and stickiness. These
differences to
the reference are fully acceptable to the skilled person.
The final breads were evaluated on taste by a trained taste panel. Results are
presented
in Table 6.
Table 6
Dough type Taste result of the bread
Test 1 The bread had an awful cardboard and a slightly bouillon-like taste.
Test 2 Salt perception almost as reference, no bitter off-taste, no bouillon-
like taste.
The results presented in Table 6 clearly demonstrate the good results obtained
if
yeast extract is used which comprises at least 15% w/w of 5'-GMP plus 5'-IMP
(and
thus at least 30% w/w 5'-ribonucleotides (sfdm)) on the basis of sodium
chloride free dry
matter.
