1. A process for production of a fermented milk product, optionally
yogurt, comprising fermenting milk using a composition comprising one or
more bacterial strains selected from the group consisting of
Streptococcus thermophilus DS71579 (Strain A), Streptococcus thermophilus
D571586 (Strain B), Streptococcus thermophilus DS71584 (Strain C),
Streptococcus thermophilus DS71585 (Strain D) and wherein the gel
strength and/or the serum viscosity of the fermented milk product
obtained, optionally yogurt, has been improved compared to the gel
strength of a fermented milk product that has not been produced using the
composition comprising one or more bacterial strains selected from the
group consisting of Streptococcus thermophilus DS71579 (Strain A),
Streptococcus thermophilus DS71586 (Strain B), Streptococcus thermophilus
DS71584 (Strain C), Streptococcus thermophilus DS71585 (Strain D).
2. A process according to claim 1 wherein the composition is comprising
Streptococcus thermophilus DS71586 (strain A).
3. A process according to claim 1 wherein the composition is comprising
Streptococcus thermophilus DS71585 (strain B).
4. A process according to claim 1, wherein the composition is comprising
Streptococcus thermophilus DS71586 (strain C).
5. A process according to claim 1, wherein the composition is comprising
Streptococcus thermophilus DS71585 (strain D).
6. A process according to claim 1, wherein the composition further
comprises one or more lactic acid bacteria selected from the group
consisting of Streptococcus thermophilus and Lactobacillus delbrueckii
ssp. Bulgaricus.
7. A process according to claim 1, wherein the composition further
comprises a Lactobacillus delbrueckii ssp. bulgaricus strain.
8. A process according to claim 7, wherein the Lactobacillus delbrueckii
ssp. Bulgaricus strain is Lactobacillus delbrueckii ssp. bulgaricus
DS71836 (strain E).
9. A process claim 7, wherein the composition comprises Streptococcus
thermophilus DS71579 (strain A) and Streptococcus thermophilus DS71586
(strain B) and Streptococcus thermophilus DS71584 (strain C) and
Streptococcus thermophilus DS71585 (strain D) and Lactobacillus
delbrueckii ssp. bulgaricus DS71836 (strain E).
10. A process according to claim 1, wherein the composition comprises
Streptococcus thermophilus DS71586 (strain B) and Streptococcus
thermophilus DS71585 (strain D) and preferably optionally Lactobacillus
delbrueckii ssp. bulgaricus DS71836 (strain E).
11. A process according to claim 7 wherein the gel strength is improved.
12. A process according to claim 7 wherein the serum viscosity is
improved.
13. A process according to claim 7 wherein the gel strength and the serum
viscosity is improved.
14. A fermented milk product, optionally yogurt, obtainable by the
process of claim 1, wherein the fermented milk product, optionally
yogurt, has an improved gel strength and/or an improved serum viscosity
compared to a fermented milk product, optionally yogurt, that has not
been produced by said process.
15. A composition comprising one or more bacterial strains selected from
the group consisting of Streptococcus thermophilus DS71579 (Strain A),
Streptococcus thermophilus DS71586 (Strain B), Streptococcus thermophilus
DS71584 (Strain C), Streptococcus thermophilus DS71585 (Strain D) for the
production of the fermented milk product, optionally yogurt as defined in
claim 14, having an improved gel strength and/or an improved serum
viscosity compared to a fermented milk product, optionally yogurt, that
has not been produced by said composition.
16. A composition for production of a fermented milk product, optionally
yogurt, said composition comprising one or more bacterial strains
selected from the group consisting of Streptococcus thermophilus DS71579
(Strain A), Streptococcus thermophilus DS71586 (Strain B), Streptococcus
thermophilus DS71584 (Strain C), Streptococcus thermophilus DS71585
(Strain D), wherein the time to reach pH 4.6 is reduced compared to a
fermented milk product, yogurt, that has not been produced by said
composition.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a composition comprising lactic
acid bacteria and a process for manufacturing fermented dairy products
using said composition.
BACKGROUND OF THE INVENTION
[0002] The food industry uses different bacteria, in the form in
particular of ferments, in particular lactic acid bacteria, in order to
improve the taste and the texture of foods but also to extend the shelf
life of these foods. In the case of the dairy industry, lactic acid
bacteria are used intensively in order to bring about the acidification
of milk (by fermentation) but also in order to texturize the product into
which they are incorporated. Among the lactic acid bacteria used in the
food industry, there can be mentioned the genera Streptococcus and
Lactobacillus. The lactic acid bacterial species Streptococcus
thermophilus and Lactobacillus delbrueckii ssp bulgaricus are used in
particular in the formulation of the ferments used for the production of
fermented milks, for example yogurts.
[0003] The acidity produced in yogurt depends mainly on the acidifying
activity of the yogurt culture (Streptococcus thermophilus and
Lactobacillus delbrueckii ssp. bulgaricus) and therefore the amount of
lactic acid produced during the milk maturation and also the residual
acidity produced during cold storage. The texture is also varying during
storage and participates in the final product sensorial properties. The
recipe of the yogurt has also an impact on the yogurt sensorial
properties by modifying the texture or the aroma perception.
[0004] Fermented milk products such as yogurts, are often fortified with
extra protein in order to increase the thickness of the products.
Proteins mostly used for this purpose are milk protein sources such as
caseinates, whey protein isolates and skim milk powder. Protein prices
are increasing because of increasing demand. This is also true for milk
proteins. Fortification of fermented milk products with milk proteins is
thus becoming more expensive. As a result dairy companies are looking for
opportunities to reduce the milk protein content that is used for
fortification of the fermented milk products.
[0005] Reduction of milk protein content in fermented milk products comes
at a cost. Milk proteins are key in generating a certain protein gel
strength within the dairy product. Reduction of the protein content thus
leads to reduction of the gel strength, and as a result the thickness of
the yogurt in sensory perception is reduced. This is undesirable and puts
a strong restriction on the extent with which the protein content can be
reduced in fermented milk products. The solution for reduction of the
protein content is to find a means to compensate for the loss in gel
strength. There are several methods known to the person skilled in the
art, such as introduction of texturizing agents. Texturizing agents, such
as stabilizers and gelatine can be used to reduce the amount of milk
protein added. While the use of texturizing agents, such as stabilizers,
in yogurt can be more cost effective than milk protein addition, their
use is restricted by regulation and labeling laws. For example, in Canada
texturizing agents may not be added to more than 2% w/w of the final
product. Also, in the EU hydrocolloids are assigned an "E number" which
may be unappealing to the consumer. In addition, enzymatic treatment,
such as transglutaminase [Lauber et al., 2000; Chr Lorenzen et al., 2002]
or heat treatment regimens [Lauber et al., 2001] may be applied to
compensate for the loss in gel strength.
[0006] The inventors have now surprisingly found a new method to
compensate for the loss in gel strength by using a starter culture
composition. The cultures of the invention have the ability to increase
the gel strength and/or the serum viscosity thereby improving the texture
of a fermented milk product with reduced protein to compensate (partly)
for the loss in thickness and creaminess of the fermented milk product.
Definitions
[0007] The term "milk" is intended to encompass milks from mammals and
plant sources or mixtures thereof. Preferably, the milk is from a mammal
source. Mammal sources of milk include, but are not limited to cow,
sheep, goat, buffalo, camel, llama, mare and deer. In an embodiment, the
milk is from a mammal selected from the group consisting of cow, sheep,
goat, buffalo, camel, llama, mare and deer, and combinations thereof.
Plant sources of milk include, but are not limited to, milk extracted
from soy bean, pea, peanut, barley, rice, oat, quinoa, almond, cashew,
coconut, hazelnut, hemp, sesame seed and sunflower seed. In addition, the
term "milk" refers to not only whole milk, but also skim milk or any
liquid component derived thereof.
[0008] As used in the present specification, the term "fermented milk
product" refers to a product that has been fermented with lactic acid
bacteria such as Streptococcus thermophilus and optionally Lactobacillus
delbruekii subsp. bulgaricus, but also, optionally, other microorganisms
such as Lactobacillus delbruekii subsp. lactis, Bifidobacterium animalis
subsp. lactis, Lactococcus lactis, Lactobacillus acidophilus and
Lactobacillus casei, or any microorganism derived therefrom. The lactic
acid strains other than Streptococcus thermophilus and Lactobacillus
delbruekii subsp. bulgaricus, are intended to give the finished product
various properties, such as the property of promoting the equilibrium of
the flora. The fermentation process increases the shelf-life of the
product while enhancing and improving the digestibility of milk. Many
different types of fermented milk products can be found in the world
today. Examples are soured milk (e.g. buttermilk), soured cream and
yogurt.
[0009] As used herein, the term "yogurt" is a fermented milk product
produced by fermentation of milk by lactic acid bacteria, also known as
"yogurt cultures". The fermentation of the lactose in the milk produces
lactic acid which acts on the milk protein to give the yogurt its
texture. Yogurt may be made from cow milk, the protein of which mainly
comprises casein, which is most commonly used to make yogurt, but milk
from sheep, goat, buffalo, camel, llama, mare, deer, water buffalo, ewes
and/or mares, and combinations thereof may be used as well. The term
"yogurt" furthermore encompasses, but is not limited to, yogurt as
defined according to French and European regulations, e.g. coagulated
dairy products obtained by lactic acid fermentation by means of specific
thermophilic lactic acid bacteria only (i.e. Lactobacillus delbruekii
subsp. bulgaricus and Streptococcus thermophilus) which are cultured
simultaneously and are found to be living in the final product in an
amount of at least 10 million CFU (colony-forming unit) per gram of the
yogurt. Preferably, the yogurt is not heat-treated after fermentation.
Yogurts may optionally contain added dairy raw materials (e.g. cream
and/or protein) or other ingredients such as sugar or sweetening agents,
one or more flavouring(s), cereals or nutritional substances, especially
vitamins, minerals and fibers. Such yogurt advantageously meets the
specifications for fermented milks and yogurts of the AFNOR NF 04-600
standard and/or the codex StanA-IIa-1975 standard. In order to satisfy
the AFNOR NF 04-600 standard, the product must not have been heated after
fermentation and the dairy raw materials must represent a minimum of 70
wt % of the finished product. Yogurt encompasses set yogurt, stirred
yogurt, drinking yogurt, Petit Suisse, heat treated yogurt and
yogurt-like products. Preferably, the yogurt is a stirred yogurt or a
drinking yogurt. More preferably, the yogurt is a stirred yogurt.
[0010] The term "starter culture composition" or "composition" (also
referred to as "starter" or "starter culture") as used herein refers to a
composition comprising one or more lactic acid bacteria, which are
responsible for the acidification of the milk base. Starter cultures
compositions may be fresh (liquid), frozen or freeze-dried. Freeze dried
cultures need to be regenerated before use. For the production of a
fermented dairy product, the starter cultures composition is usually
added in an amount from 0.01 to 3%, preferably from 0.01 and 0.02% by
weight of the total amount of milk base.
[0011] As used herein, the term "lactic acid bacteria" (LAB) or "lactic
bacteria" refers to food-grade bacteria producing lactic acid as the
major metabolic end-product of carbohydrate fermentation. These bacteria
are related by their common metabolic and physiological characteristics
and are usually Gram positive, low-GC, acid tolerant, non-sporulating,
non-respiring, rod-shaped bacilli or cocci. During the fermentation
stage, the consumption of lactose by these bacteria causes the formation
of lactic acid, reduces the pH and leads to the formation of a (milk)
protein coagulum. These bacteria are thus responsible for the
acidification of milk and for the texture of the fermented milk product.
[0012] As used herein, the term "lactic acid bacteria" or "lactic
bacteria" encompasses, but is not limited to, bacteria belonging to the
genus of Lactobacillus spp., Bifidobacterium spp., Streptococcus spp.,
Lactococcus spp., such as Lactobacillus delbruekii subsp. bulgaricus,
Streptococcus thermophilus, Lactobacillus lactis, Bifidobacterium
animalis, Lactococcus lactis, Lactobacillus casei, Lactobacillus
plantarum, Lactobacillus helveticus, Lactobacillus acidophilus and
Bifidobacterium breve.
[0013] The term "improvement" or "improved" as used in improvement of one
or more of the attributes related to texture as defined herein below,
means an improvement of one or more of the attributes related to texture
obtained while using the composition of the invention as defined herein
below in comparison with a composition comprising lactic acid bacteria
other than at least strain B or at least strain D, or at least the
combination of strain B and strain D. In the Examples such a composition
has been used as the Reference. A control experiment without lactic acid
bacteria is of course meaningless since in that case no fermented milk
product such as yogurt can be obtained and no comparison can be made. An
improvement in one or more of the attributes related to texture may be
measured absolutely for instance in the case of Brookfield (Pa*s units)
or shear stress (Pa units) or more relatively by a taste panel for
instance for all the sensory aspects of the fermented milk product.
DETAILED DESCRIPTION OF THE INVENTION
[0014] In a first aspect the invention provides a process for the
production of a fermented milk product, preferably yogurt, comprising
fermenting milk using a composition comprising one or more bacterial
strains selected from the group consisting of Streptococcus thermophilus
DS71579 (Strain A), Streptococcus thermophilus DS71586 (Strain B),
Streptococcus thermophilus DS71584 (Strain C), and Streptococcus
thermophilus DS71585 (Strain D) and wherein the gel strength and/or the
serum viscosity of the fermented milk product obtained, preferably
yogurt, has been improved compared to the gel strength of a fermented
milk product that has not been produced using the composition comprising
one or more bacterial strains selected from the group consisting of
Streptococcus thermophilus D571579 (Strain A), Streptococcus thermophilus
DS71586 (Strain B), Streptococcus thermophilus DS71584 (Strain C),
Streptococcus thermophilus DS71585 (Strain D). One preferred embodiment
of the process of the invention is using a composition comprising at
least strain A. Another preferred embodiment of the process of the
invention is using a composition comprising at least strain B. Another
preferred embodiment of the process of the invention is using a
composition comprising at least strain C. Another preferred embodiment of
the process of the invention is using a composition comprising at least
strain D.
[0015] The advantage of the process of the invention is that strain A as
well as strain B as well as strain C as well as strain D is capable of
improving the gel strength and/or the serum viscosity of a fermented milk
product such as yogurt. Strain A as well as strain B as well as strain C
as well as strain D used in the process of the invention is not only
capable of improving the gel strength and/or the serum viscosity of the
fermented milk products such as yogurt as such, but in particular strain
A as well as strain B as well as strain C as well as strain D, as well as
the below compositions 1 to 37, are capable of partially or fully
restoring the gel strength and/or the serum viscosity of the fermented
milk product such as yogurt wherein the protein content has been reduced,
to the gel strength and/or the serum viscosity of the fermented milk
product such as yogurt wherein the protein content not has been reduced.
Therefore, instead of adding additional protein in the process of the
invention for the production of a fermented milk protein such as yogurt
with an improved gel strength and/or the serum viscosity, a composition
comprising the lactic acid bacteria strain A or strain B or strain C or
strain D as defined herein before may be used in the process of the
invention in order to obtain an improved gel strength and/or serum
viscosity.
[0016] Another advantage of the present invention is that the present
strains provide an improved acidification rate, i.e. the time to reach pH
4.6. A reduced time to reach pH 4.6 is advantageous for large scale
production of yogurt wherein it is beneficial to reduce manufacturing
time of the yogurt. In a preferred embodiment, the present composition
comprising one or more bacterial strains provides a time to reach pH 4.6
of less than 400 minutes, preferably less than 380 minutes, more
preferably less than 360 minutes for yogurts having a protein content of
smaller than 4.0%. In another preferred embodiment, the present
composition comprising one or more bacterial strains provides a time to
reach pH 4.6 of less than 500 minutes, preferably less than 450 minutes,
more preferably less than 420 minutes, most preferably less than 400
minutes for yogurts having a protein content of more than 4.0%.
[0017] Preferred compositions to be used in the process of the invention
are the following.
[0018] Compositions comprising at least 1 strain from the group consisting
of strain A and strain B and strain C and strain D. [0019] 1. Composition
comprising at least Streptococcus thermophilus strain A. [0020] 2.
Composition comprising at least Streptococcus thermophilus strain A and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E. [0021] 3.
Composition comprising at least Streptococcus thermophilus strain B.
[0022] 4. Composition comprising at least Streptococcus thermophilus
strain B and a Lactobacillus delbrueckii ssp. bulgaricus preferably
strain E. [0023] 5. Composition comprising at least Streptococcus
thermophilus strain C. [0024] 6. Composition comprising at least
Streptococcus thermophilus strain C and a Lactobacillus delbrueckii ssp.
bulgaricus preferably strain E. [0025] 7. Composition comprising at least
Streptococcus thermophilus strain D. [0026] 8. Composition comprising at
least Streptococcus thermophilus strain D and a Lactobacillus delbrueckii
ssp. bulgaricus preferably strain E.
[0027] Compositions comprising at least 2 strains from the group
consisting of strain A and strain B and strain C and strain D. [0028] 9.
Composition comprising at least Streptococcus thermophilus strain A and
strain B [0029] 10. Composition comprising at least Streptococcus
thermophilus strain A and strain B and a Lactobacillus delbrueckii ssp.
bulgaricus preferably strain E. [0030] 11. Composition comprising at
least Streptococcus thermophilus strain A and strain C [0031] 12.
Composition comprising at least Streptococcus thermophilus strain A and
strain C and a Lactobacillus delbrueckii ssp. bulgaricus preferably
strain E. [0032] 13. Composition comprising at least Streptococcus
thermophilus strain A and strain D. [0033] 14. Composition comprising at
least Streptococcus thermophilus strain A and strain D and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E. [0034] 15.
Composition comprising at least Streptococcus thermophilus strain B and
strain C [0035] 16. Composition comprising at least Streptococcus
thermophilus strain B and strain C and a Lactobacillus delbrueckii ssp.
bulgaricus preferably strain E. [0036] 17. Composition comprising at
least Streptococcus thermophilus strain B and strain D. [0037] 18.
Composition comprising at least Streptococcus thermophilus strain B and
strain D and a Lactobacillus delbrueckii ssp. bulgaricus preferably
strain E. [0038] 19. Composition comprising at least Streptococcus
thermophilus strain C and strain D [0039] 20. Composition comprising at
least Streptococcus thermophilus strain C and strain D and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E.
[0040] Compositions comprising at least 3 strains from the group
consisting of strain A and strain B and strain C and strain D. [0041] 21.
Composition comprising at least Streptococcus thermophilus strain A and
strain B and strain C. [0042] 22. Composition comprising at least
Streptococcus thermophilus strain A and strain B and strain C and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E. [0043] 23.
Composition comprising at least Streptococcus thermophilus strain A and
strain B and strain D. [0044] 24. Composition comprising at least
Streptococcus thermophilus strain A and strain B and strain D and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E. [0045] 25.
Composition comprising at least Streptococcus thermophilus strain B and
strain C and strain D. [0046] 26. Composition comprising at least
Streptococcus thermophilus strain B and strain C and strain D and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E. [0047] 27.
Composition comprising at least Streptococcus thermophilus strain A and
strain C and strain D. [0048] 28. Composition comprising at least
Streptococcus thermophilus strain A and strain C and strain D and a
Lactobacillus delbrueckii ssp. bulgaricus preferably strain E.
[0049] Compositions comprising at least 4 strains from the group
consisting of strain A and strain B and strain C and strain D. [0050] 29.
Composition comprising at least Streptococcus thermophilus strain A and
strain B and strain C and strain D. [0051] 30. Composition comprising at
least Streptococcus thermophilus strain A and strain B and strain C and
strain D and a Lactobacillus delbrueckii ssp. bulgaricus preferably
strain E. [0052] 31. Composition ABCDE as defined in Table 2. [0053] 32.
Composition AE as defined in Table 2. [0054] 33. Composition BE as
defined in Table 2. [0055] 34. Composition CE as defined in Table 2.
[0056] 35. Composition DE as defined in Table 2. [0057] 36. Composition
BDE as defined in Table 2. [0058] 37. Composition BD as defined in Table
2.
[0059] Each of the 37 compositions listed above may encompass different
embodiments depending on the amount of the strains present in the
composition. The individual strains in the compositions may constitute
any suitable percentage of the total cfu's (colony forming units) in the
compositions. In the composition comprising only one of the strains A, B,
C and D, these strains may constitute 100% of the cfu's.
[0060] Each of the 37 compositions may however, comprise further other
lactic acid bacterial strains. In those compositions, the total cfu's
relates not only to the strains A and/or B and/or C and/or D and/or E
present in the composition but also to the other bacterial strains
present in the compositions. The composition may further comprise other
lactic acid bacterial strains as defined hereinbefore such as one or more
lactic acid bacterial strains selected from the group consisting of
Lactobacillus spp., Bifidobacterium spp., Streptococcus spp., Lactococcus
spp., such as Lactobacillus delbruekii subsp. bulgaricus, Streptococcus
salivarius thermophilus or Streptococcus thermophilus, Lactobacillus
lactis, Bifidobacterium animalis, Lactococcus lactis, Lactobacillus
casei, Lactobacillus plantarum, Lactobacillus helveticus, Lactobacillus
acidophilus and Bifidobacterium breve. Preferably the composition used in
the process of the invention may further comprise one or more other
Streptococcus thermophilus strains or one or more other Lactobacillus
delbrueckii ssp. bulgaricus strains. These strains may be added because
they may have other properties that are advantageous in for instance a
process for the production of a fermented milk product such as yogurt or
in the final properties of the fermented milk product such as yogurt.
These strains may for instance further improve the acidification speed or
they may confer certain flavours such as in the case of adjunct cultures.
[0061] Lactobacillus delbrueckii ssp. bulgaricus strain is a classical
yogurt strain and may be present in the composition to be used in the
process of the invention. The inventors have found, however, that the
Lactobacillus delbrueckii ssp. bulgaricus strain did not contribute to
(the improvements of) any of the texture attributes. Yogurts made with a
composition that is lacking a Lactobacillus delbrueckii ssp. bulgaricus
gave the same values of the texture attributes compared to the same
composition comprising a Lactobacillus delbrueckii ssp. Bulgaricus, such
as strain E.
[0062] Lactobacillus delbrueckii ssp. bulgaricus, when present in the
compositions of the invention, preferably strain E (Lactobacillus
delbrueckii ssp. bulgaricus DS71836) may constitute between 0.1% and 10%
of the total cfu's of the composition, preferably between 0.2% and 5%,
more preferably between 0.5% and 2%, more preferably between 0.8 and
1.2%, most preferably 1%. Strain E in the compositions used in the
process of the invention (Lactobacillus delbrueckii ssp. bulgaricus
DS71836) comprising 2 or more strains of which at least one strain is
strain E, constitutes between 0.1% and 10% of the total cfu's of the
composition, preferably between 0.2% and 5%, more preferably between 0.5%
and 2%, more preferably between 0.8 and 1.2%, most preferably 1%.
Preferably, the Streptococcus thermophilus strains A, B, C and D
constitute the remaining cfu's of the composition of the invention.
[0063] In the compositions comprising one Streptococcus thermophilus
strain (A or B or C or D) and strain E, strain E may be present as
described above, i.e. between 0.1% and 10% of the total cfu's of the
composition, preferably between 0.2% and 5%, more preferably between 0.5%
and 2%, more preferably between 0.8 and 1.2%, most preferably 1%. In
those compositions, the Streptococcus thermophilus strain constitutes the
remaining cfu's whereby the total cfu's is 100%.
[0064] The strains in the compositions comprising two or three or four of
the Streptococcus thermophilus strains A, B, C and D may constitute the
individual Streptococcus thermophilus strains in any suitable percentage
of the total Streptococcus thermophilus cfu's in the composition. In the
compositions comprising two or more of the Streptococcus thermophilus
strains and strain E, strain E is present as described above, i.e.
between 0.1% and 10% of the total cfu's of the composition, preferably
between 0.2% and 5%, more preferably between 0.5% and 2%, more preferably
between 0.8 and 1.2%, most preferably 1%. In those compositions, the
Streptococcus thermophilus strains constitute the remaining cfu's whereby
the total cfu's is 100%.
[0065] The most preferred fermented milk product that is produced by the
process of the second aspect of the invention is yogurt as defined
hereinbefore. The milk that may be used in the process of the third
aspect of the invention, may be any milk suitable for the production of a
fermented milk product, such as yogurt. Milk has been defined
hereinbefore and may encompass milks from mammals and plant sources or
mixtures thereof. Preferably, the milk is from a mammal source. Mammal
sources of milk include, but are not limited to cow, sheep, goat,
buffalo, camel, llama, mare and deer. In an embodiment, the milk is from
a mammal selected from the group consisting of cow, sheep, goat, buffalo,
camel, llama, mare and deer, and combinations thereof. Plant sources of
milk include, but are not limited to, milk extracted from soy bean, pea,
peanut, barley, rice, oat, quinoa, almond, cashew, coconut, hazelnut,
hemp, sesame seed and sunflower seed. In addition, the term "milk" refers
to not only whole milk, but also skim milk or any liquid component
derived thereof. The fat content in the milk and in the subsequent
fermented milk product, such as yogurt, may be as is known in the prior
and as is referred in the background of the invention.
[0066] In one preferred embodiment, the invention provides a process for
the production of a fermented milk product, preferably yogurt, wherein
the gel strength is improved. In another preferred embodiment, the
invention provides a process for the production of a fermented milk
product, preferably yogurt, wherein the serum viscosity is improved. Most
preferred is an embodiment, wherein the invention provides a process for
the production of a fermented milk product, preferably yogurt, wherein
both the gel strength and the serum viscosity is improved.
[0067] In a further preferred embodiment, the invention provides a process
for the production of a fermented milk product, preferably yogurt,
wherein the protein level is reduced. More preferably the invention
provides a process for the production of a fermented milk product,
preferably yogurt, wherein the protein level is reduced while the the gel
strength and/or the serum viscosity is maintained. More preferably the
present invention provides a process for the production of a fermented
milk product, preferably yogurt, wherein the protein level is less than
12%, less than 11%, less than 10%, less than 9.5%, less than 9.0%, less
than 8.5%, less than 8.0%, less than 7.5%, less than 7.0%, less than
6.5%, less than 6.0%, less than 5.5%, less than 5.0%, less than 4.9%,
less than 4.8%, less than 4.7%, less than 4.6%, less than 4.5%, less than
4.4%, less than 4.3%, less than 4.2%, less than 4.1%, less than 4.0%,
less than 3.9%, less than 3.8%, less than 3.7%, less than 3.6%, less than
3.5%, less than 3.4%, less than 3.3%, less than 3.2%, less than 3.1% or
less than 3.0% of the fermented milk product, preferably yogurt.
[0068] In a second aspect, the invention provides a fermented milk
product, preferably yogurt, obtainable by the process of the first aspect
of the invention and comprising one of the compositions as defined
hereinbefore, preferably composition 1 or composition 2 or composition 3
or composition 4 or composition 5 or composition 6 or composition 7 or
composition 8 or composition 9 or composition 10 or composition 11 or
composition 12 or composition 13 or composition 14 or composition 15 or
composition 16 or composition 17 or composition 18 or composition 19 or
composition 20 or composition 21 or composition 22 or composition 23 or
composition 24 or composition 25 or composition 26 or composition 27 or
composition 28 or composition 29 or composition 30 or composition 31 or
composition 32 or composition 33 or composition 34 or composition 35 or
composition 36 or composition 37 characterized in that the fermented milk
product, preferably yogurt, has an improved gel strength and/or an
improved serum viscosity compared to a fermented milk product, preferably
yogurt, that has not been produced by the process of the first aspect of
the invention and/or does not comprise one of the compositions as defined
hereinbefore.
[0069] In a preferred embodiment, the fermented milk product, preferably
yogurt, obtainable by the process of the first aspect of the invention
comprises less than 12%, less than 11%, less than 10%, less than 9.5%,
less than 9.0%, less than 8.5%, less than 8.0%, less than 7.5%, less than
7.0%, less than 6.5%, less than 6.0%, less than 5.5%, less than 5.0%,
less than 4.9%, less than 4.8%, less than 4.7%, less than 4.6%, less than
4.5%, less than 4.4%, less than 4.3%, less than 4.2%, less than 4.1%,
less than 4.0%, less than 3.9%, less than 3.8%, less than 3.7%, less than
3.6%, less than 3.5%, less than 3.4%, less than 3.3%, less than 3.2%,
less than 3.1% or less than 3.0% protein content.
[0070] In a further preferred embodiment, the present fermented milk
product, preferably yogurt, obtainable by the process of the first aspect
of the invention comprises a reduced protein content if compared with a
fermented milk product, preferably yogurt that has not been produced by
the process of the first aspect of the invention and/or does not comprise
one of the compositions as defined hereinbefore. Preferably the reduced
protein content is a reduction of at least 5%, preferably at least 10%,
more preferably at least 15%, most preferably at least 20%.
[0071] It is found by the present inventors that the above protein
contents, or reduced protein content, is combined with a gel strength
and/or serum viscosity which is maintained, or not reduced, if compared
with a fermented milk product, preferably yogurt, wherein the protein
content, or reduced protein content, has not been reduced.
[0072] In a third aspect, the invention provides the use of any of one of
the compositions as defined hereinbefore, preferably composition 1 or
composition 2 or composition 3 or composition 4 or composition 5 or
composition 6 or composition 7 or composition 8 or composition 9 or
composition 10 or composition 11 or composition 12 or composition 13 or
composition 14 or composition 15 or composition 16 or composition 17 or
composition 18 or composition 19 or composition 20 or composition 21 or
composition 22 or composition 23 or composition 24 or composition 25 or
composition 26 or composition 27 or composition 28 or composition 29 or
composition 30 or composition 31 or composition 32 or composition 33 or
composition 34 or composition 35 or composition 36 or composition 37 for
the production of the fermented milk product, preferably yogurt as
defined in any of claims 22, having an improved gel strength and/or an
improved serum viscosity compared to a fermented milk product, preferably
yogurt, that has not been produced by such a composition.
[0073] In a preferred embodiment, the present invention relates to the use
of any of the compositions 1 to 37, such as composition 17 or 24, for the
production of a fermented milk product, preferably yogurt, wherein the
time to reach pH 4.6 is reduced compared to a fermented milk product,
preferably yogurt, that has not been produced by any of the composition 1
to 37 such as composition 17 or 24.
[0074] In a further preferred embodiment, the present invention relates to
the use of any of the compositions 1 to 37, such as composition 17 or 24,
for the production of a fermented milk product, preferably yogurt, having
a reduced protein content compared to a fermented milk product,
preferably yogurt, that has not been produced by any of the composition 1
to 37 such as composition 17 or 24. Preferably the reduced protein
content is a reduction of at least 5%, preferably at least 10%, more
preferably at least 15%, most preferably at least 20% if compared with a
fermented milk product, preferably yogurt, that has not been produced by
any of the composition 1 to 37 such as composition 17 or 24.
FIGURES
[0075] FIG. 1 is a graph showing the shear stress at a shear rate of 215
s-1 for four different lactic acid blends in yogurt of three different
protein levels.
[0076] FIG. 2 is a graph showing the shear stress for four different
lactic acid blends over the shear rate of 10 to 1000 s-1 in a yogurt with
3.4% protein.
[0077] FIG. 3 is a graph showing the shear stress for four different
lactic acid blends over the shear rate of 10 to 1000 s-1 in a yogurt with
3.8% protein.
[0078] FIG. 4 is a graph showing the shear stress for four different
lactic acid blends over the shear rate of 10 to 1000 s-1 in a yogurt with
4.2% protein.
[0079] FIG. 5 is an overview of stirring the yogurt before measuring the
shear stress.
MATERIALS AND METHODS
1. Bacterial Strains.
TABLE-US-00001
[0080] TABLE 1
Bacterial strains
Strain CBS number Strain
A CBS134831 Streptococcus thermophilus DS71579
B CBS134834 Streptococcus thermophilus DS71586
C CBS134832 Streptococcus thermophilus DS71584
D CBS134833 Streptococcus thermophilus DS71585
E CBS134835 Lactobacillus delbrueckii ssp. bulgaricus DS71836
All strains A-E were deposited on 9 Apr. 2013 at the Centraalbureau voor
Schimmelcultures (Fungal Biodiversity Centre), Uppsalalaan 8, 3584 CT
Utrecht, The Netherlands under the provisions of the Budapest Treaty.
2. Compositions Comprising Bacterial Strains
[0081] The following compositions were used in the Examples. The
percentages relate to the cfu's (colony forming units)--see Table 2.
TABLE-US-00002
TABLE 2
Compositions comprising bacterial strains - the % values relate to the
cfu's of the respective strain in the composition.
Composition Strain A Strain B Strain C Strain D Strain E
ABCDE 24.75% 24.75% 24.75% 24.75% 1%
AE 99.0% -- -- -- 1%
BE -- 99.0% -- -- 1%
CE -- -- 99.0% -- 1%
DE -- -- -- 99.0% 1%
BDE -- 49.5% -- 49.5% 1%
BD 50% 50%
The Reference culture (Ref) used in the examples is a commercially
available yogurt starter culture and does not contain any of strains A-E.
3. Yogurt Preparation (All Examples)
[0082] The fermented milk used is obtained by supplementing pasteurized
skimmed milk (Campina, The Netherlands) with skimmed milk powder and
cream (containing 39% fat). The final recipe is described in the
different examples. The milk mixture is pasteurized at 92.degree. C. for
6 minutes. In line homogenization takes place in the heating part of the
pasteurizer at 60.degree. C., in two stages of 80 and 40 bar. The
homogenized, pasteurized milk is cooled back to the fermentation
temperature (38.degree. C.) and inoculated with the culture to be tested
at a rate of 0.02% (w/w) Once a pH of 4.60 is reached, the yogurt is
smoothened by pumping the yogurt through a sieve (poresize 500 .mu.m).
The yogurt is then filled out into suitable containers. The yogurt cups
are then stored at 4.degree. C.
4. Yogurt Recipes
[0083] The following recipes were used in the Examples. All additions are
wt % of the total milk recipe.
TABLE-US-00003
TABLE 3
Yogurt recipes
Recipe
Ingredient (%) A B C D E F G
Skimmed Milk 96.0 81.6 82.2 87.7 0 0 0
Semi skimmed Milk 0 0 0 0 91.4 90.1 88.7
Skimmed Milk 0.4 0.0 6.3 1.0 0.9 2.2 3.6
Powder
Cream (39% fat) 3.6 3.8 3.8 3.6 0 0 0
Sucrose 0.0 7.7 7.7 7.7 7.7 7.7 7.7
Demineralized water 0.0 6.9 0.0 0.0 0 0 0
Fat concentration 1.4 1.5 1.5 1.4 1.4 1.4 1.4
Protein 3.5 2.9 5.1 3.5 3.4 3.8 4.2
concentration
5. Shear Stress of Yogurt
[0084] The samples were measured using a Physica MCR501 rheometer equipped
with a concentric cylinder measurement system (CC-27). A solvent trap was
used to prevent evaporation of water as much as possible. Yogurt samples
are stored at 4.degree. C. and are taken out of storage just prior to
measuring in the rheometer, with the containers having to be handled with
extreme care (as any sudden movements might damage the yogurt
microstructure and thus lead to differences in results). As shown in FIG.
5, the closed container is turned from an upright position to a tilted
one with an angle of 100.degree., so that the container lid is now the
lowest point. At this point, one has to turn the container 3 times around
its axis (3.times.360.degree., .about.4 seconds per revolution), to
slightly stir the yogurt without really damaging its structure.
Subsequently the container is turned back into a normal upright position
and can be opened. Once opened, one has to ascertain that there is no
dried in material at the top of the container: if that is the case, this
dried in material needs to be removed on one side (the side along which
the yogurt will be poured). The container can then be slightly turned
again to its side till the yogurt level reaches the top of the container
at which time the yogurt can be gently spooned out of and over the top of
the container into the measuring cup. Once filled the measuring cup is
placed into the Physica Rheometer and superfluous material is removed by
using a pipette. The procedure to load the yogurts takes about two
minutes. Care needs to be taken to treat all different samples in exactly
the same way, since difference in loading conditions can cause
differences in the relative ranking of the yogurts. Before measurement
the samples were allowed to rest and heat/cool to the measuring
temperature (25.degree. C.) for 5 minutes.
[0085] A standard experimental protocol was applied consisting out of the
following two measuring sequences: [0086] 1. A strain sweep to
determine the initial gel strength (dynamic shear modulus): this is an
oscillatory test where at a fixed angular frequency (omega=10 rad/s) an
increasing amplitude is applied: on a logarithmic scale the amplitude is
increased from 0.01 to 100% with 5 measuring points per decade. [0087] 2.
After the strain sweep the yogurts are allowed to rest for 30 seconds in
the rheometer and subsequently a shear rate sweep is applied to determine
the shear stress in mouth: This consists of applying an increasing shear
rate to the yogurts ranging from 0.001 to 1000 s-1 on a logarithmic scale
with 3 measuring points per decade (no fixed time setting: the rheometer
software determines the required shearing time per measuring point). This
experiment gives a flow curve whereby the measured stress is plotted as a
function of the applied shear rate. This curve can then be combined with
literature data to determine the relevant shear stress in the mouth as
explained in the following.
[0088] By sensory panelling of various food products Shama and Sherman
identified windows of instrumental shear stresses and shear rates
corresponding to products with similar thickness ratings but different
shear-thinning behavior. These windows correspond to the rheological
regimes applied in the mouth during thickness rating. The governing shear
rate was shown to be dependent on the viscosity of the product itself.
(see FIG. 1 from Shama, F. and Sherman, P. Journal of Texture Studies, 4,
111-118. (1973), "Identification of stimuli controlling the sensory
evaluation of viscosity II oral methods").
[0089] For the yogurts of the examples below the (predicted) shear stress
in the mouth is determined by plotting the experimentally measured flow
curves (measured shear stress in function of applied shear rate of the
shear rate sweep experiment described above) onto the aforementioned FIG.
1 from Shama and Sherman. The predicted shear stress in the mouth is
defined as the cross-over between the measured flow curves and the upper
bound of the "shear rate shear stress" windows of FIG. 1 of Shama and
Sherman. In FIG. 2 the authors give examples for various food stuffs. The
thus derived shear stress gave a good correlation with the sensory
perception of thickness in the mouth.
6. Brookfield
[0090] Viscosity measurement were performed using a Brookfield RVDVII+
Viscometer, which allows viscosity measurement on an undisturbed product
(directly in the pot). The Brookfield Viscometer determines viscosity by
measuring the force required to turn the spindle into the product at a
given rate. The Helipath system with a T-C spindle was used as it is
designed for non-flowing thixotropic material (gels, cream). It slowly
lowers or raises a rotating T-bar spindle into the sample so that not
always the same region of the sample is sheared (helical path). Thus, the
viscometer measures constantly the viscosity in fresh material, and is
thus thought to be the most suitable for measuring stirred yogurt
viscosity. A speed of 30 rpm was used for 31 measuring points, at an
interval of 3 sec. The average of the values between 60 and 90 seconds
are reported.
7. Serum Viscosity
[0091] A yogurt can be seen as a two-phase system: a protein rich phase
embedded into a water-rich serum phase. The viscosity of such a system
will be determined by the collective contribution of the two phases. In
order to determine the contribution of the serum phase, the latter has
been isolated by centrifugation of tubes filled with 40 g yogurt each in
a BHG Hermle Z320 centrifuge (1 h at 4000 RPM/2500 g). The clear serum
phase is decanted. This serum viscosity is measured using a Physica MCR
300 Rheometer. After loading, a shear rate sweep is applied to the
samples: This consists of applying an increasing shear rate to the
yogurts ranging from 40 s.sup.-1 to 1000 s.sup.-1 on a logarithmic scale
with 5 measuring points per decade. The serum viscosity is defined as the
measured viscosity at 100 s.sup.-1.
8. Gel Strength
[0092] The samples were measured using a Physica MCR501 rheometer equipped
with a concentric cylinder measurement system (CC-27). A solvent trap was
used to prevent evaporation of water as much as possible. The samples
were slightly stirred with a spoon before loading into the rheometer.
Before measuring, the samples were allowed to rest and brought to the
measuring temperature (25.degree. C.) and maintained at that temperature
for 5 minutes. In order to determine the gel strength (i.e. the dynamic
shear modulus G (Pa)), a strain sweep is applied to the sample: this is
an oscillatory test where at a fixed angular frequency (omega=10 rad/s)
an increasing amplitude is applied: on a logarithmic scale the amplitude
is increased from 0.01 to 100% with 5 measuring points per decade. The
gel strength of a material is defined as the average of the measured
moduli between the strain of 0.01% to 0.25% (so in the linear regime).
9. Sensory Analysis
[0093] In a sensory analysis the attributes thickness of mouth feel and
ropiness are analysed. Thickness of mouth feel is the degree in which the
product feels thick in the mouth. This sensation can be best perceived
between tongue and palate. Ropiness is the degree in which the yogurt
runs from the spoon.
[0094] The method used to perform the sensory analysis for the ropy
structure and thickness in mouth feel was a ranking test. The panelists
received the four products simultaneously in random order. The assessors
were asked to rank the samples according to the specified attribute from
least to most. The two attributes were assessed separately using new
three digit codes to avoid any bias. The results were obtained by using
the software FIZZ acquisition (Biosystemes, France, Couternon). Hereafter
the results were computed by using the Friedman test (analysis of
variance by ranks). As four products per recipe have to be measured,
three sessions were held, resulting in 22 observations per measurement.
The sum of ranks is calculated by measuring the total allocated 1, 2, 3
or 4 points, wherein 1 point is allocated for the lowest rank and 4
points for the highest rank.
EXAMPLES
Example 1
Effect of Lactic Acid Bacterial Strains on the Gel Strength and the Serum
Viscosity of a Yogurt
[0095] Yogurt was made according to recipe A as defined in Table 3 and
according to the method described in the Materials and Methods.
[0096] The results show that all compositions BE, DE, BDE and ABCDE
improve the gel strength and serum viscosity compared to the Reference
composition.
Example 2
Effect of Lactic Acid Bacterial Strains on the Gel Strength of a Yogurt
[0097] Yogurt was made according to recipe D as defined in Table 3 and
according to the method described in the Materials and Methods.
TABLE-US-00005
TABLE 5
Composition (see Table 3)
Attribute Reference ABCDE AE BE CE DE BDE
Time to reach pH = 4.6 495 468 1102 434 853 1094 343
(min)
Brookfield (Pa * s) 6.5 8.6 5.5 7.8 5.1 8.1 14
Shear stress (Pa) 20 23 16 24 15 18 39
Gel strength 71 74 76 84 80 75 111
dynamic modulus G*
(Pa)
[0098] The results show that all composition AE, BE, CE, DE, BDE and ABCDE
improve the gel strength compared to the Reference composition.
Example 3
Effect of Lactic Acid Bacterial Strains on the Gel Strength of a Yogurt
with Different Protein Contents
[0099] Yogurt was made according to recipe B, C and D as defined in Table
3 and according to the method described in the Materials and Methods.
TABLE-US-00006
TABLE 6
Time to
reach Gel Shear
Protein pH 4.6 Strength Stress Brookfield
Composition Recipe (%) (min) (Pa) (Pa) (Pa * s)
ABCDE B 2.9 370 39 20 7.4
ABCDE C 5.1 450 179 40 22.7
ABCDE D 3.5 466 74 23 8.6
BDE D 3.5 450 111 38 13.8
Reference D 3.5 495 71 19.6 6.4
[0100] The results in table 6 clearly show that increasing the protein
content of a yogurt (2.9-3.5-5.1%), increases the gel strength (39-74-179
Pa respectively), the shear stress (20-23-40 Pa respectively) as well as
the Brookfield of the yogurt (7.4-8.6-22.7 Pa*s respectively).
[0101] The results in table 6 also show that ABCDE and BDE are increasing
the gel strength, the shear stress as well as the Brookfield of the
yogurt when compared with the Reference composition.
[0102] The results in in table 6 furthermore show that composition BDE,
compared to ABCDE, even further increases the gel strength, the shear
stress as well as the Brookfield of the yogurt with a protein content of
3.5% (recipe D).
[0103] In particular, composition BDE increases the gel strength of the
yogurt with 3.5% protein made with ABCDE (74 Pa) to the gel strength of a
yogurt with .about.4.5% protein (made with ABCDE), This can be deduced by
interpolation of the data obtained with ABCDE as the 3 protein levels
(not shown). Similarly, composition BDE increases the shear stress of the
yogurt with 3.5% protein made with ABCDE (23 Pa) to the shear stress of a
yogurt with .about.5.0% protein (made with ABCDE). Finally, composition
BDE increases the Brookfield of the yogurt with 3.5% protein made with
ABCDE (8.6 Pa*s) to the Brookfield of a yogurt with .about.5.0% protein.
Example 4
Effect of Lactic Acid Bacterial Strains on the Time to Reach pH 4.6, Shear
Stress and Viscosity of a Yogurt with Different Protein Contents, in
Comparison with Commercially Available Strains
[0104] Yogurt was made according to recipe E, F and G as defined in Table
3 and according to the method described in the Materials and Methods.
Additionally starter culture TA40 and YO-MIX.TM. 883 were used to
inoculate the recipe E, F and G. TA40 and YO-MIX.TM. 883 are both
commercially available from Danisco A/S and comprise Streptococcus
thermophilus and Lactobacillus delbrueckii strains. Both cultures are
known for providing thickness, as is exemplified for TA40 for example in
FIG. 1 of US2009/0226567.
TABLE-US-00007
TABLE 7
Time to
reach Shear
Protein pH 4.6 Stress Brookfield
Composition Recipe (%) (min) (Pa) (Pa * s)
BD E 3.4 318 59 8.2
BDE E 3.4 356 56 7.1
TA40 E 3.4 467 44 5.4
YO-MIX .TM. 883 E 3.4 n.a. 44 5.6
BD F 3.8 339 62 10.3
BDE F 3.8 368 58 8.3
TA40 F 3.8 443 50 6.8
YO-MIX .TM. 883 F 3.8 861 52 6.4
BD G 4.2 366 68 12.1
BDE G 4.2 412 66 10.9
TA40 G 4.2 523 58 8.6
YO-MIX .TM. 883 G 4.2 838 58 8.7
[0105] The results in Table 7 clearly show that BD and BDE increase the
shear stress as well as the Brookfield of the yogurt when compared with
the TA40 and YO-MIX.TM. 883. Furthermore, Table 7 clearly shows that the
time to reach pH 4.6 is lower for BD and BDE at all protein levels.
[0106] Similarly FIG. 1 shows the shear stress at 215 s-1 (PA) for
compositions BD, BDE, TA40 and YO-MIX.TM. 883 for recipes E, F and G.
FIG. 1 clearly shows a higher shear stress for compositions BD and BDE in
comparison with TA40 and YO-MIX.TM. 883 for all three recipes E, F and G.
Thus, BD and BDE increase the shear stress even in recipes with reduced
amounts of protein, i.e. from 4.2 to 3.8 and 3.4% protein.
[0107] Moreover, BD is able to provide a shear stress/Brookfield in yogurt
recipe E having 3.4% protein of 59 Pa, while TA40 and YO-MIX.TM. 883
provide a comparable shear stress of 58 in yogurt recipe G having 4.2%
protein. Thus, by using BD the protein can be reduced with 0.8% of the
yogurt while maintaining the shear stress. In other words, BD provides a
reduction in protein level of 19%.
[0108] FIGS. 2 to 4 show the shear stress versus shear rate for
compositions BD, BDE, TA40 and YO-MIX.TM. 883 for recipe E, F and G
having 3.4, 3.8 and 4.2% protein, respectively. FIGS. 2 to 4 shows that
the higher shear stress of composition BD and BDE when compared with TA40
and YO-MIX.TM. 883 is consistent over the shear rate of 10 to 300
s.sup.-1, which is the relevant range for determination of shear stress
in yogurts.
Example 5
Effect of Lactic Acid Bacterial Strains on Serum Viscosity of a Yogurt
with Different Protein Contents, in Comparison with Commercially
Available Strains
[0109] Similar to example 4, yogurt was prepared with recipes E, F and G
with lactic acid bacteria BD, BDE, TA40 and YO-MIX.TM. 883. Table 8 below
shows the results of the measured serum viscosity
TABLE-US-00008
TABLE 8
Protein Serum viscosity
Composition Recipe (%) (mPa * s)
BD E 3.4 2.19
BDE E 3.4 2.15
TA40 E 3.4 1.90
YO-MIX .TM. 883 E 3.4 2.12
BD F 3.8 2.37
BDE F 3.8 2.38
TA40 F 3.8 2.11
YO-MIX .TM. 883 F 3.8 2.35
BD G 4.2 2.50
BDE G 4.2 2.44
TA40 G 4.2 2.21
YO-MIX .TM. 883 G 4.2 2.43
[0110] As can be seen in Table 8, the serum viscosity of BD and BDE is
improved if compared with the serum viscosity of TA40 and YO-MIX.TM. 883
for recipe E, F and G having 3.4, 3.8 and 4.2% protein. In comparison
with TA40, BD is nearly able to provide the TA40 serum viscosity of 2.21
in yogurt with 4.2% protein, however in a yogurt having only 3.4%
protein. Thus BD is able to improve serum viscosity and reduce the
protein content of yogurt.
Example 6
Effect of Lactic Acid Bacterial Strains in a Sensory Panel Test of a
Yogurt with Different Protein Contents, in Comparison with Commercially
Available Strains
[0111] Similar to example 4, yogurt was prepared with recipes E, F and G
with lactic acid bacteria BD, BDE, TA40 and YO-MIX.TM. 883. To study the
perceived gel strength and serum viscosity by a sensory panel, a panel
test is carried out as described in the materials and methods. The
attribute ropiness is linked with serum viscosity, and the attribute
thickness of mouth feel is linked with gel strength.
TABLE-US-00009
TABLE 9
Sum of ranks
Protein Sum of ranks `Thickness of mouth
Composition Recipe (%) `ropiness` feel`
BD E 3.4 59 65
BDE E 3.4 63 62
TA40 E 3.4 59 36
YO-MIX .TM. 883 E 3.4 40 57
BD F 3.8 68 64
BDE F 3.8 57 54
TA40 F 3.8 55 57
YO-MIX .TM. 883 F 3.8 41 45
BD G 4.2 58 63
BDE G 4.2 72 48
TA40 G 4.2 57 54
YO-MIX .TM. 883 G 4.2 34 55
[0112] In Table 9 the highest sum of ranks per yogurt recipe are written
in bold. Table 9 clearly shows that BD and BDE have the highest sum of
ranks and are thus perceived as providing the most ropiness or providing
the most thickness in the mouth.
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