Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR OBTAINING SINAPIC ACID FROM A NATIVE MATERIAL MIXTURE
The present invention relates to a method for obtaining sinapic
acid and/or a salt of sinapic acid from a native material
mixture.
It is known to obtain a protein phase as a valuable material
phase from seeds having hard frangible husks, in particular from
oil seed rape fruits.
In the familiar approach for protein concentrate production, the
grain meal (greatly deoiled) is washed, wherein the soluble
extracted materials are depleted. The value of the deoiled
intermediates depends greatly on the concentration of
accompanying materials, such as fibers, sugars and secondary
plant materials (Menner, M. et al. "Fraktionierung pflanzlicher
Rohstoffe zur simultanen Erzeugung von Lebensmitteln,
technischen Rohstoffen und Energietragern" [Fractionation of
plant raw materials for simultaneous production of foods,
technical raw materials and energy carriers], Chemie Ingenieur
Technik, volume 81, edition 11, pages 1743 - 1756, November
2009). These accompanying materials also include polyphenols
such as sinapine. The polyphenol acid "sinapic acid" occurs
primarily in rape seeds (there the sinapine content is
approximately 640 mg/100 g of oil seed rape). In order to
separate off accompanying materials such as sinapine, large
dilutions are chosen, proteins are also denatured (temperature,
alcohol), cellulose is enzymatically broken down to form
short-chain carbohydrates; these methods are chosen in order to
be able to extract the materials better.
- 2 -
Against this background, the problem addressed by the invention
is to further optimize obtaining valuable materials from the
native material mixture, wherein it is to be possible, in
particular, to obtain in a relatively simple manner a sinapine,
a sinapic acid or derivatives of sinapic acid.
SUMMARY
Accordingly, there is described a method for obtaining at least
one of sinapic acid and a salt of sinapic acid from a native
material mixture comprising the following steps:
- step A): providing a native material mixture of
seeds/fruits having hard frangible husks comprising oil seed rape
fruits of the Brassicaceae family;
- step B): if the native material mixture of step A is not
yet comminuted: comminuting the native material mixture;
- step C): dispersing the comminuted native material
mixture of step A) or B) with water, wherein, to one part of
comminuted native material mixture up to a maximum of 8 parts of
water are added, and wherein the water and the native comminuted
material mixture are agitated such that one of a free-flowing
pulp and a dispersion results;
- step D): setting the pH of the pulp from step C) to an
alkaline range pH > 9.5;
- step E): adding a water-soluble organic solvent, to the
pulp from step C) subsequent to the setting of the pH of the pulp
in step D) in order to detach the husks from endosperm of the
seeds and fruits;
- step F): separating off a solids phase which has the
predominant fraction of the husks;
- step G): shifting the pH of the pulp which is freed from
husks from step F) to the pH range from pH = 4.5 to pH = 7.2;
Date Recue/Date Received 2022-01-18
- 2a -
- step H): separating the husk-free pulp, the pH of which
has been shifted to the acidic range in step G) into a plurality
of phases, wherein at least one of said plurality of phases is a
polyphenol-albumin liquid phase; and
- step I): isolating at least one of the sinapic acid and
the salt of sinapic acid from the husk-free pulp of step F) or
G) or from the polyphenol-albumin liquid phase of step H)
directly or after the husk-free pulp passes through further
intermediate steps, by an extraction with an extraction medium.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the present invention are illustrated, merely by way
of example, in the following drawings in which:
Figures la and lb illustrate different batches of different raw
materials or starting materials plus water used in embodiments
of the current process, wherein the batch amounts are normalized;
Figure 2 is a schematic diagram showing the overall process
according to an embodiment.
In more detail, in an embodiment, the steps of the described
process involve:
Step A:
As starting material, a native material mixture is provided from
seeds having hard frangible husks, in particular from
- seeds/fruits of crucifers (Brassicaceae), in particular
of oil seed rape fruits.
Date Recue/Date Received 2022-01-18
- 2b -
The material mixture within the meaning of this application can
consist of the complete, but broken, seeds. These can be unhusked
or partially husked or completely husked.
Alternatively, the material mixture can also consist of a
previously deoiled product, in particular of an "intermediate",
that is to say of a press cake which remains as residue of
obtaining oil after a "preliminary stage", e.g. after pressing
off oil, in particular using a press (e.g. a screw press).
Date Recue/Date Received 2022-01-18
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Particularly preferably, the starting material processed is
"intermediate obtained shortly before", that is to say after the
preliminary stage no more than 31 days must have passed.
The seed can be freshly harvested or else be days, weeks or
months old, the intermediate stage (the pressing) should take
place shortly before, or even immediately before, the further
processing in order that, after obtaining the oil, the
material - the seed - has not changed too greatly.
Highly preferably, the starting material processed is "fresh
material", i.e., after a preliminary stage, or preliminary
processing (obtaining oil), no more than three days must have
passed, preferably even only fewer than 48 hours or 24 hours or
12 hours or fewer than 1 hour.
Using material from a time period shortly after the preliminary
stage, good results are achieved or, and using fresh material,
generally even better results are achieved with respect to the
yield and purity of the products of value.
The press cake can have a residual oil content that can even be
20% or more. Despite such high residual oil contents, even
obtaining a protein phase using the invention is achievable in a
simple manner. Obtaining the protein, however, is only optional.
The sinapic acid and/or the sinapine salt can therefore be
obtained as the sole product of value of the material mixture,
or as an additional product of value during obtaining of
protein.
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Step B:
If it is not yet comminuted: comminuting the material mixture of
step a) to break open the husks. If a press cake is used, said
press cake is broken open, ideally immediately after pressing,
still warm. In this manner, a comminuted material - of
granule type - is generated from the press cake. The material
mixture that is (partially) deoiled beforehand by a pressing
operation is generally only comminuted, for example crumbled or
granulated, or at all events the husks are broken open.
Step C:
13 The material mixture that is provided and comminuted from step
A) or B) is dispersed with water or an aqueous solution (e.g. a
salt solution). To one part of "comminuted product", preferably
up to a maximum of 8, preferably up to a maximum of 5, parts
(weight fractions) of water are added. Then, water and
comminuted product are stirred, such that a free-flowing pulp or
a dispersion results. The stirring preferably proceeds for more
than 30 min, in particular for more than 1 h.
Step D)
Next, the pH of the pulp (I) from step c) is set to an alkaline
range; preferably, the pH of the pulp or of the dispersion is
set to pH 10 to 11 using alkali metal hydroxide solution. In
this case, the stirring is continued (carefully). The stirring
time is preferably more than 30 min, preferably it is 1 h or
more.
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Step E)
In this further step, at least one water-soluble organic
solvent, preferably alcohol, is added, in particular in
water-diluted form, subsequently to setting the pH of the pulp
in step D. Preferably, the dispersion, the pH of which has been
set to the alkaline range, is brought to an alcohol
concentration of 20-15% by volume or less, using the alcohol
Et0H (preferably 30-60%), in particular a concentration of 12%
Et0H. Corresponding to the amount of water of the alcohol used,
the amount of water in step C can be reduced by the water
present in the alcohol, in particular in the 30-60% Et0H. The
husks thereby detach from the endosperm (cotyledon) with the
residual oil and can be separated off, in particular
centrifugally.
As less preferred alternative in comparison with ethanol, other
alcohols, such as, e.g., isopropanol, can also be used.
The steps C-E can proceed together, for example simultaneously
in time. Thus, it is, e.g., possible to set an aqueous highly
dilute ethanol solution using alkali metal hydroxide solution to
a correspondingly basic pH and to add this solution to the
comminuted material mixture.
Step F)
In step F), therefore, a solids phase is separated off, which
comprises the predominant fraction of the husks, preferably in a
centrifuge in the centrifugal field, from the pulp, or the pulp
is clarified from husk and solids fractions, in particular in a
decanter.
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In this step, the husks are separated from the residual pulp
using a decanter having a feed.
The lighter phase of a centrifugal phase separation will
hereinafter also occasionally be termed as overflow, and the
solids phase as heavy phase. A middle phase may correspondingly
lie inbetween, relating to the density thereof.
Step G)
The at all events substantially husk-free pulp from step F) is
then further processed. Preferably, in this case, the dissolved
protein fraction is precipitated out of the husk-free pulp,
which protein fraction, together with the non-dissolved or
solubilized protein portion, forms a fraction, the curd. The pH
in this case is shifted back to the acidic range, in particular
to the pH range from pH = 4.5 to pH = 7.
Step H)
Then, the husk-free pulp, the pH of which has been shifted back
to the acidic range, is separated - preferably in a centrifuge,
in particular in at least one decanter or in a separator - in
one or two steps into valuable material phases, of which one
phase is a protein concentrate phase and one of said phases is a
polyphenol-albumin liquid phase.
Particularly preferably, a separation into the following two or
three phases takes place:
- oil-containing phase
- aqueous phase (polyphenol- and sinapic acid-containing)
- protein concentrate phase (hereinafter also called "protein
curd") or
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- aqueous phase with albumin and polyphenol contents and
residual oil content; and
- protein concentrate phase (protein curd).
The two-phase separation is carried out when the raw material is
relatively highly deoiled and/or is present in bound form in the
solids, or if an intensive shearing effect has not been
implemented for the liquid phase in step 1. The addition of
water or alcohol or alkali metal hydroxide solution or the like
can also proceed in substeps. The oil as a lighter phase
contains triglycerides and is one of the valuable materials that
may be obtained.
Step I): Isolating sinapic acid or the sinapines from the
husk-free pulp of step F) or - and this is particularly
preferred - from the polyphenol-albumin liquid phase of step H)
directly or after passage through further intermediate steps, in
particular by an extraction using an extraction medium, in
particular after addition of an extraction medium to the
husk-free pulp of step F) or C). In particular, ethyl acetate is
suitable, which will be demonstrated hereinafter with reference
to experiments. However, pentanol is also usable.
Hereinafter, mostly sinapic acid and sinapic acid-containing
phases and material mixtures are mentioned. Of course, however,
depending on the pH, sinapic acid can also be present as sinapic
acid esterified with choline.
Preferably, the temperature during all of the method steps is
below 60 C, in particular below 50 C, preferably between 40 C
and 50 C, as a result of which particularly valuable products
may be obtained.
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The denaturation of the proteins is a temperature- and
time-dependent process. In addition, there is the condition in
the alcoholic milieu. The protein denaturation proceeds the more
rapidly the higher the temperature is. In an aqueous
environment, however, under the action of heat of 45-50 C,
irreversible protein denaturation is also not to be expected.
However, this changes with the alcohol concentration. Even at
ambient temperature, in highly concentrated alcohol, a protein
precipitation may be observed.
The lower then the alcohol concentration is, the higher must the
temperature be in order to denature the proteins. Or vica versa:
the more aqueous the alcohol concentration is, the higher may
the working temperature be without the proteins being
irreversibly damaged.
Therefore, (for pure water) a temperature that is as high as
possible, that is to say as far as possible reaching to 60 C,
will be chosen in order to bring as many substances as possible
into solution, such as proteins, lecithins, glycolipids, etc.
The precipitated proteins are present as protein curd (heavy
phase).
The advantageous temperature data for the method steps A to H
does not relate to the pressing temperature during generation of
the press cake in the oil production. The higher the temperature
was in the preceding process steps, the browner the protein
phase or curd fraction becomes. This firstly concerns the
Maillard reaction of sugars with proteins, and secondly phenol
oxidation. In comparison with DE 10 2011 050 905 Al,
in
particular owing to the use of optimally selected starting
materials (preferably cold-pressed oil seed rape press cake,
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preferably very fresh), a particularly attractive, particularly
readily reusable product is obtained.
The use of cold-pressed materials (in particular a cold-pressed
oil seed rape press cake; temperature during pressing
advantageously below 70 C, particularly preferably even below
60 C) as starting material or as the material mixture provided
is particularly advantageous. Warm-pressed material is exposed
during pressing to markedly higher temperatures (up to above
100 C). By using cold-pressed material as starting material for
the method according to the invention, a protein phase or
"protein and/or curd phase" having markedly improved properties
(in particular with respect to the color markedly brighter and
therefore more readily processable) and having markedly improved
yield can be obtained than is the case when warm- or hot-pressed
starting material is used. This has not been acknowledged to
date in the prior art. This is because customary oil seed rape
pressing methods are targeted at a high oil yield, for which
reason, during pressing, relatively high temperatures are
willingly used. As a side effect, it may be observed that
sinapine (a polyphenol) is broken down, which in itself would
seem to be advantageous for the protein fraction. In the method
according to the invention, the original, that is to say non-
reduced, sinapine content in the cold-pressed cake, however,
nevertheless is not a problem for the end product, since the
polyphenolic compounds are substantially not recovered in the
curd phase, since they transfer into the water phase.
In this case, the curd phase which was obtained by the method
according to the invention from a press cake previously
additionally deoiled with hexane is rather to be assigned to the
RAL color 1024 ochre yellow or 1014 ivory or a mixture of these
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two colors. The processing preferably proceeds at ambient
pressure.
In the liquid phase and/or "water phase" of step H), valuable
constituents are still also present, in particular it has a
relatively high albumin content. To this extent, it would be
logical and advantageous to perform a filtration of the water
phase for albumin concentration, in order in this manner to
obtain the albumin phase as a further valuable material.
As a further valuable constituent, sinapic acid and/or sinapine
and/or polyphenols may be obtained from the liquid phase and/or
"water phase" of step H).
This is possible in a simple manner in that the sinapic acid is
extracted from the aqueous phase using an extraction medium that
is suitable therefor. As suitable extraction medium, in
particular ethyl acetate and pentanol are suitable, wherein
preference is given to ethyl acetate.
Alternatively, it is conceivable to perform the extraction of
sinapic acid directly from the liquid
phase - the
protein-containing pulp - of step F) using an extraction medium
that is suitable therefor.
A particularly advantageous method variant may be explained with
reference to the following example.
Step A) The starting material provided in this example is
pressed oil seed rape cake, ideally pressed under mild and cold
conditions, having typical residual oil contents of 20%; but
higher contents are not a problem.
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Step B) The cake is broken open, ideally directly after
pressing, still warm.
Step C) The cake granules are dispersed with water (1 part cake
and a maximum of 6 parts water) and are to be stirred carefully
(1 h).
Step D) This dispersion is to be set to pH 10 to 11 using alkali
metal hydroxide solution and carefully stirred, usually for 1 h.
Step E) The dispersion from 4 is to be brought to an Et0H
concentration of 12% by volume using Et0H (preferably
30-60% - based on percent by volume); the amount of water in
point 3. is thereby reduced by the water present in said 30-60%
Et0H.
Step F) The husks thereby detach from the endosperm (cotyledon)
with the residual oil and can be separated off centrifugally.
Step G) Precipitation of the protein by acidification to
preferably pH = 4.5 to 7.2 out of the overflow (overflow: light
phase of the separation from step S6 having a pH from preferably
9.7 to 10.5) for the separation: oil - aqueous phase - protein
concentrate phase (protein curd) or for separation into
oil/water phase and protein concentrate phase; this step can be
supported by intensive shearing in order to facilitate the oil
release.
Step H) Separating off the precipitated proteins as curd (heavy
phase (generally solids phase, or here curd phase)) and
optionally triglycerides (as light oil) from the overflow (light
phase), in particular centrifugally.
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Step I) Filtration of the water phase for albumin concentration.
The wet separation of the husks from the dissolved and swollen
proteins in a parallel displacement extraction of the
triglycerides (oil phase) from oil-containing or residual oil-
containing press cake or legume meal and parallel polyphenol
extraction may be mentioned as particularly advantageous.
The particular advantages of the method are:
Low dilutions and thus small volumetric streams are achievable
in the process via the above-described method with
simultaneously low solvent waste.
This gives a higher polyphenol concentration during the
extraction in the aqueous phase (method steps 2 to 5).
Native temperature-sensitive proteins are in addition present in
the end product, since the process is implemented at a maximum
of 50-55 C or below.
Overall, comparatively high protein yields of up to 75% by
weight are achievable, wherein up to 45-50% by weight can be
obtained from the "curd phase" and approximately 22-24% by
weight from the albumin phase.
A relatively high-quality end product (protein mixture) can be
obtained, because husk residues, and also polyphenols,
carbohydrates, lignin, cellulose, etc. are completely removed or
depleted.
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The protein phase contains "native" protein, the swellable
fraction of which remains swellable after it is obtained, and
the water-dissolvable fractions of which remain water-soluble
after they are obtained. The protein phase is in addition
virtually triglyceride-free and has only low residual oil
values, principally polar lipids.
The good milieu for microorganism growth due to the slight
alcohol concentration simplifies the process hygiene.
The alcohol can be circulated in dilute form.
With regard to steps A) and B):
Instead of the extraction of unwanted materials from the highly
deoiled, very finely comminuted starting material oil seed rape
meal or oil seed rape cake - as is usual in the familiar
methods - here first the husks are separated off in the wet
state. This is solved in a multistage process in that first the
cake is broken up, without the kernel fragments being further
comminuted.
In particular, it is important to leave the husks as large as
possible. Preferably, they should have a mean diameter of 0.5 mm
or greater. Oil droplets do not need to be greater; what is of
importance is not individual molecules or small molecule
aggregates, but "particles".
Then, water is added and the mixture is carefully stirred in
alkaline conditions. The water-soluble part of the proteins is
dissolved thereby, another part swells. The addition of aqueous
alcohol displaces the free triglyceride as a specific light
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gravity phase out of the dispersion. The lecithins, in
particular phosphatidyl cholines, are soluble at low alcohol
concentrations (see EP 1272048 Bl and associated patent family).
In this combination of alkali metal hydroxide solution - aqueous
alcohol, the two or three phases are
1) Heavy = husks and
2)
light = protein-lecithin-polyphenol-carbohydrate together with
oil-containing foam; or
1) Heavy = husks, 2) medium - protein-lecithin-polyphenol-
carbohydrate, 3) light = triglyceride, advantageously separable,
for instance in the experiment in the glass beaker or on an
industrial scale, preferably by centrifugation.
The better the husks are separated off, the lower are the
protein losses and the purer is the end product. Even the husk
swollen up to 7 times by addition of water is heavier than the
proteins in the alcoholic-aqueous dispersion. This is essential
for separation by gravitation. However, the separation is made
more difficult by firm adhesion of the protein-containing
aleurone bodies (honeycomb layer) to the husks. These cells are
thick-walled. Since the cell membrane of virtually all cells
contains lecithins (in addition to proteins and other
substances), the adhesion can now be minimized by suitable
measures by "solubilizing" of the lecithins.
Specifically, this is achieved by the aqueous phase having an
alcohol concentration of 5-40% by volume (see steps S2-S4),
ideally 12% to 20%.
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The quality of the starting material is critical therefor. The
residual oil content is usually higher in the case of
cold-pressed cake. This does not interfere in the case of the
method presented here. On the contrary: the gentle pressing is
extremely helpful; the more moderate is the pressing temperature
and the lower the pressing force, the easier is subsequent
separation of husks and cotyledon (germ layers, the kernel
interior).
The method is also applicable with "usual", that is to say
hot-pressed, press cake. Only in this case are the yields of
proteins correspondingly lower.
Regarding steps C) to E) (dispersion production):
Producing the dispersion with water-aqueous alkali metal
hydroxide solution and alcohol has two aims: firstly, the
detachment from the husk, secondly the extraction of phenolic
compounds such as sinapine from the raw material. In this case,
the wetting with fluid is of importance. However, a shearing in
the case of the dispersion formulation in steps 2-5 generated
very small particles that led to impurities in the separated
phases. Without use of a shear-head mixer, or without using a
toothed-wheel mixer for steps 2-5, the protein content in the
protein phase (after the step in which it is obtained and a
drying) was: > 60% by weight in the case of fresh material.
Using a shear-head mixer, or using a Frisam shear mixer, the
protein content in the protein phase (the step in which it is
obtained and a drying) was: approximately 50% in the case of old
material.
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Another test was carried out using hot-pressed expeller cake.
The amount of removable husks in the first stage is decreased by
the shearing from 20% to 16%, and at the same time the amount of
precipitable protein from the clear phase is increased from 38%
by weight to 42% by weight. The purity remains relatively
constant and low at 39-40% by weight.
The water-aqueous alkali metal hydroxide solution and alcohol
dispersion is stirred at a temperature of T = 50 C for about 30
min.
In addition to dissolution of the lecithins in the
aqueous-alcoholic solution, for improved separation of husks
firstly, and triglycerides secondly, separating off the husks in
the slightly alcoholic solution has the additional advantage
that growth of microorganisms in the process is made more
difficult. This is a marked advantage in comparison with the
purely aqueous method and facilitates the CIP cleaning.
Regarding step F) separation
The separation will be described hereinafter with reference to
some examples for better illustration.
Example:
El) A cold-pressed protein-containing cake which is processed as
far as step F, after processing thereof, has the following
phases: 17% heavy phase as husk fraction from the feed with 20%
of the cake proteins and 83% overflow as protein-
polyphenol-oil-phosphatide phase having 80% of the cake
proteins.
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B2) A warm-pressed cake, which is processed up to step F, has,
after processing thereof, the following phases: 26% heavy phase
as husk fraction from the feed having 30% of the cake proteins
and 74% overflow as protein-polyphenol-oil-phosphatide phase
having 70% of the cake proteins.
B3) A hot-pressed cake, which is processed in step F, after
processing thereof has the following phases: 30% heavy phase as
husk fraction from the feed having 50% of the cake proteins and
70% overflow as protein-polyphenol-oil-phosphatide phase having
50% of the cake proteins.
Regarding step G) - protein precipitation
The proteins are precipitated out of the overflow
(overflow - light phase) of the separation in the preceding step
by pH shifting to the range from 4.5 to approximately 7. The
water-insoluble proteins which, however, are swellable in
aqueous solution form, together with the precipitated globulins,
the protein fraction of the "protein curd". The liquid in this
fraction has the same composition as the liquid of the middle
phase (overflow without triglycerides). Since, however, the curd
phase only makes up 10-30% by weight of the feed, (having a
relatively high fraction of dry matter, 15-25% by weight of dry
matter), quantitatively, substantially fewer polyphenols may
also be found in the curd phase than in the middle phase, even
if the concentration of the polyphenols, based on the water, is
the same.
Therefore, a protein phase of water-insoluble but swollen
proteins with globulins is available, which is depleted with
polyphenols. This combination of alkaline-ethanolic milieu in
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steps A-F, followed by an acid-alcohol milieu for protein
precipitation, represents very good conditions for a polyphenol
extraction. Surprisingly, for oil seed rape (sinapine and
derivatives), here the observation for other polyphenols
(tyrosol and derivatives, inter alia) from other fields such as
the processing of olives is confirmed, although significantly
more reactive substances such as proteins and sugars are present
in the suspension.
Therefore, dilutions such as described in the literature are
irrelevant in order to arrive at equivalent polyphenol
extraction rates of the aqueous mixture (for instance, again
Kroll et al., "Rapssamenproteine - Struktur,
Eigenschaften,
Gewinnung und Modifizierung" [Oil seed
rape proteins -
structure, properties, production and modification], Deutsche
Lebensmittel-Rundschau, volume 3, 2007, p. 109).
Since the pure triglyceride is displaced from the liquid as a
light phase, the residual oil content in the protein end product
can be reduced to below 15% by weight, also below 13% by weight,
based on dry matter.
Since the temperatures during the entire process are <= 50 C,
this can also be described as a native end product.
If the pulp that is to be processed further is sheared before
the phase separation of step H (before the oil separation) and
after step F) or G) of claim 1, this is advantageous for
improving the displacement extraction. This shearing can be
carried out using a shearing device such as, e.g., a
homogenizer, or an intensive mixer, in order to obtain still
more oil in this manner.
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The shearing can be carried out using a shearing device in a
continuous process. Overall, preferably, a continuous process is
implemented.
Regarding step H) - separation of the proteins as curd by means
of decanter or separator
To increase the purity, the protein curd can be washed. The curd
can then be dried to form a powder.
Regarding step I) - isolating the sinapic acid, the sinapine or
a derivative of sinapic acid
Subsequently, advantageously sinapic acid is obtained by means
of an extraction and optionally an albumin phase is obtained
(the latter, for example, by filtration).
In short, an advantageous method for obtaining proteins from
native material mixtures is also provided, having the following
steps:
A) providing a native material mixture of seeds having hard
frangible husks,
B) breaking up or coarsely comminuting the material mixture in
order in any case to break open the husks without dispersing
them too finely. Preferably, the size of the comminuted husk
fractions in a granulometric distribution by type should be
between 100 and 2000 pm, in particular having a maximum between
300 pm and 900 pm, in particular approximately 600 pm, in each
case at a relative frequency of greater than 5%;
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C) dispersing the comminuted broken-open material mixture from
step A) or B) with water or an aqueous solution;
D) setting the pH of the pulp (I) from step C) to an alkaline
range of pH > 9,5;
E) adding the water-soluble organic solvent alcohol to the pulp
of step C) subsequently to setting the pH of the pulp in step D;
F) separating off a solids phase which has the predominant
fraction of the husks, preferably in a centrifuge in the
centrifugal field;
G) shifting the pH of the pulp freed from husks from step F) to
the pH range from pH = 4.5 to pH = 7.2, and
H) separating the husk-free pulp, the pH of which has been
shifted back to the acidic range - preferably in a centrifuge,
in particular in at least one decanter - in one or two steps
into the following three valuable material phases: oil-
containing phase having a triglyercol content; aqueous phase
having an albumin content and protein concentrate phase (protein
curd).
When the oil content is very low in the raw material, the oil
phase is absent and only two phases are formed, the aqueous
albumin phase and the protein concentrate phase.
It is further advantageous if the curd phase is dried. Here it
is advantageous to vaporize alcohol still present out of the
curd, preferably under vacuum, in order to keep the temperature
low and to dry the alcohol-free aqueous curd to form a powder.
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For this purpose, for example, a drying and a grinding are
advantageous; for implementation thereof in an apparatus, the
drier-pulverizer is suitable. In this manner, a storage-stable,
readily handleable and also transportable product is provided.
The beneficial properties can be illustrated with reference to a
protein phase obtained in the experiment:
Experiment 1 (regarding steps A-F): experimental batch: 95 kg of
tap water + 23 kg of oil seed rape (warm pressing) were charged
into an agitator reservoir and heated to 40 C (steps A and C).
Subsequently, this product/water mixture was circulated by means
of a monopump and a Fristam mixer at 1000 l/h for approximately
8 min (pH = 6.2). Then 4.1 1 of 10% NaOH are added and the pH is
set to 10 (step D).
The mixture was subsequently circulated without the Fristam
mixer at 1000 l/h for 15 min and stirred. Then 14.2 kg of
ethanol are added (step E in one or more substeps) by means of a
peristaltic pump directly to the circuit of the monopump.
Residence time: preferably 10-50 min. After approximately 50 min
residence time, again 2 kg of ethanol in 11 kg of water are
mixed and added to an agitator vessel. 10 min residence time.
This suspension is separated centrifugally (step F). In this
case the yield is: 96.5 kg of clear phase, 34 kg of solids. The
husks may be readily separated off thereby.
Experiment 2: (A-F) experimental batch: 116 kg of tap water and
26 kg of oil seed rape (cold pressing) were charged into the
agitator reservoir and heated to 40 C. Subsequently, the mixture
was circulated (pH = 5.8) by means of monopump and Fristam mixer
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at 1000 l/h for approximately 8 min. Addition of 4.5 1 of 10%
NaOH to pH = 10. Subsequently, the mixture was circulated for 15
min without the Fristam mixer at 1000 1/h. Then 17.2 kg of
ethanol were added by means of a peristaltic pump directly into
the circuit of the monopump. There is a 10 minute residence
time. Thereafter the mixture is separated in order to separate
off the husk fraction. The yield is yield: 129.6 kg of clear
phase, 26.5 kg of solids. The husks may be more readily
separated off thereby.
Experiment 3: (steps G and H to experiment 1): 96.5 kg of clear
phase from experiment 1 (starting pH: 9.6) were shifted to pH 5
by means of 0.8 1 of 25% hydrochloric acid, here advantageously
at 45 C (step G). This pulp can then be centrifuged, wherein a
protein phase is obtained as heavy phase or solids phase (step
H). Yield of clear phase: 64.3 kg. Yield of solids phase
(curd-type) 9 kg.
Experiment 4 (steps G and H to experiment 2): 129.6 kg of clear
phase from experiment II (starting pH: 9.5) were shifted to pH 5
by means of 1.2 1 of 25% hydrochloric acid at 45 C (step G).
This pulp could then be centrifuged, wherein a protein phase was
obtained as heavy phase or solids phase (step H). Yield: 83 kg
of clear phase, 29.5 kg of solids/protein phase. Here the yield
of solids phase is particularly high.
Typically, a powder obtained from a curd obtained in the manner
of the abovementioned experiments and then dried has dry matter
contents of 5-9%; in a sample produced from conventional press
cake 5.35%. The protein content is approximately 60%. The water-
binding capacity was determined at 1.8 +/- 0.2 ml H20 per 1 g of
dry matter of the protein powder, the oil-binding capacity at
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0.49 to 0.63 g of oil per 1 g of dry matter, and also the
emulsifiability at 700 to 780 ml of oil per 1 g of dry matter of
the protein powder. Typical values for the protein solubility
index NSI are 9 to 16%. The best results are achieved with the
cold-pressed press cake.
In further experiments it was surprisingly found that the
stirring technique in the method is also of importance, which
relates, in particular, to the stirring of step C) (and
optionally D) and E)) of claim 1.
Thus, cold-pressed oil seed rape press cake was processed in the
procedure described in claim 1. In this case, in step C),
stirring was performed once using a blade agitator and once
using a propeller agitator.
The blade agitator should be operated in such a manner that it
generates the fewest possible shearing forces during the
stirring but generates a substantially uniform laminar flow.
In the case of the propeller agitator in the meaning of this
application, stirring elements are also connected outside the
axis of rotation, thus, via a disk or a ring or in the vicinity
thereof, elements such as an open bell are present over the
propeller elements. They therefore generate a relatively
turbulent flow during stirring and exert higher shearing forces
on the product.
Blade agitators are therefore those which substantially generate
a laminar flow during stirring, which have relatively long
blades and which are operated at a low speed of rotation. A ring
or a disk or the like on the outer periphery of the blades or in
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the vicinity thereof (in the manner of an open cage or an open
bell around the blades) is generally not present.
In the further experiments, the husk-containing solids phase
according to step F) was separated off after steps D) and E) -
preferably with further stirring using the blade agitator or
the propeller agitator.
The liquid phase after separating off the husks from a
suspension of oil seed rape press cake, which contained 13.4%
oil, 31.4% protein and 55.2% others (such as cellulose,
polyphenols, saccharides, etc.), when the blade agitator was
used for stirring in step C) and optionally D) and E), was
markedly protein-richer than when a propeller agitator was used.
Approximately 75% of the proteins of the cake were found in this
overflow, the dry matter of which is composed of 52.3% protein,
13.0% oil and approximately 34% others. In contrast, only 62.5%
of the proteins of the cake were found in the comparable
overflow, when a propeller agitator was used. For this case, the
overflow dry matter had only approximately 37% protein,
approximately 14.7% oil and also 48.0% other constituents.
Surprisingly, marked differences were also found visually. The
husk fraction of the centrifuge sample from the suspension using
the blade agitator appeared markedly marbled. In this case only
42% of the dry matter was separated off as overflow; in the case
of the propeller agitator, the fraction of the dry matter
separated off was 50%.
Furthermore, still more advantageous method variants could be
found.
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Thus, a high alcohol concentration, in particular ethanol
concentration, causes a high oil content in the "globulin curd".
It is particularly advantageous in step E), therefore, when the
alcohol concentration is less than 20% by volume, in particular
13 to 18% by volume, particularly preferably 15% by volume.
An excessively long reaction time at pH 10 (overnight) likewise
causes high oil contents in the globulin curd. Somewhat lower
temperatures, in particular below 43 C, act advantageously in
the globulin precipitation and globulin separation, and give
rise to higher protein contents in the curd.
In addition, one or more of the following further measures
appear to be particularly advantageous: the use of fresh
materials during pressing of the oil; cold pressing of the oil
and a gentle stirring with a blade agitator (in step C), wherein
the material should be sheared or ground as little as possible.
In addition, an advantageous alcohol content, in particular
ethanol content, of less than 20% is particularly advantageous,
since otherwise a higher oil content results in the curd.
For the obtaining of sinapic acid of step I), experiments have
likewise been carried out.
Thus, it has been found that in a pretreatment of steps C), D)
and E), the sinapic acid is enriched in the "water phase". It is
therefore obtainable by extraction using a suitable extraction
medium, more precisely either after step H) or even after step
F).
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In this case, however, the choice of starting material also has
an effect on the amount of obtainable sinapic acid.
For this purpose, reference may be made to the diagrams of the
accompanying figures la and b. In the individual experiments,
different batches of different raw material or starting material
plus water were selected, wherein the samples, although they
contained different amounts, the amount was normalized or
suitably converted.
The two diagrams show that the polyphenol content in the aqueous
phase can increase to more than 4-fold if, as starting material,
"cold-pressed oil seed rape press cake" is used instead of
"hot-pressed oil seed rape press cake". The use of fresh
material is also advantageous to this extent. This is because,
just as the polyphenol fraction is enriched in the water phase,
it is depleted in the protein curd phase. Thus, in the case of a
hot-pressed cake, the fraction of 9.4% polyphenols (dry matter
"DM" in the raw material) is depleted to 5.6% by weight DM in
the protein curd or curd powder, or in the cold-pressed cake
from 18.6% by weight DM to 10.1% by weight DM in the curd
powder. Therefore, this concentration of the polyphenols based
on the dry matter in the solids is only about half as great as
in the starting material.
Therefore, a protein phase of water-insoluble but swollen
proteins with globulins is available that has been depleted with
respect to the polyphenol content. In the water phase,
approximately 55-55% by weight of the polyphenols remain in the
following concentrations:
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Cake type Dilution in PP In the PP in the
the method water phase water phase
(mg) normalized
Parts of to a
water based dilution 1
on 1 part of part seed +
cake 6 parts
fluid
Cold 4.5 3976 2982
Warm 4.2 3183 2228
Hot 6.0 1053 1058
The following influence factors should be heeded in the
processing: in the hot pressing, polyphenols (PP) are broken
down. It has been measured that the PP content in clear-pressed
seed was 18 mg/g, but in the case of hot-pressed seed was
8.8 mg/g. Similar values are known from the literature (6.2 mg/g
in Jeroch et al. 1999). In addition to the reduction of the
polyphenols in the raw material, the sinapine is deesterified to
form sinapic acid.
Via the cold pressing, according to the abovementioned method,
the polyphenols are transferred most highly in terms of quantity
in the cold pressing into the water phase or more precisely
"polyphenol-albumin phase" of step H). They are present, as a
result of the alkaline pretreatment (+ temperature and Et0H),
substantially as sinapic acid or salts of sinapic acid, and no
longer as sinapine and not yet as canolol.
It is henceforth advantageous to extract the sinapic acid in one
step I) from the aqueous phase using an extraction medium, in
particular ethyl acetate. For this purpose,
the
polyphenol-albumin phase was washed with ethyl acetate, or
alternatively with pentanol.
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a) with 1/1 (PP-albumin phase/ethyl acetate)
b) with 1/2 (PP-albumin phase/ethyl acetate)
c) with 1/1 (PP-albumin phase/pentanol)
d) with 1/2 (PP-albumin-phase/pentanol)
The once-extracted polyphenol phase as valuable material phase
of stages a) to d) was in each case washed a further time (2nd
extraction). This was performed with the original pH from 5.2 to
5.4, and repeated once more at pH 4. This gave the following
table of results:
Extraction Extraction Extraction Extraction
rate in % rate at pH rate at pH rate at pH
by weight 5.2 and 4 4 and 2nd
at pH 5.2 2nd stage stage
a ethyl 74.6 78.2 72.5 90.8
acetate
ethyl 57.8 77.0 82.7 91.1
acetate
2nd wash
74.6 84.8 85.6 87.4
pentanol
61.1 80.7 85.5 92.1
pentanol
2nd wash
Extraction with ethyl acetate appears to be particularly
advantageous. This is again advantageously added in the aqueous
mixture in the ratio 1/0.5 to 1/3 (quantitative ratio:
PP-albumin phase/ethyl acetate). The ethyl acetate can be
vaporized at the end.
The above-described steps are again clearly shown in fig. 2.
