Protein preparation produced from rape seeds
The present invention relates to a protein preparation
produced from rape seeds and to a method for producing such,
a protein preparation.
Protein preparations are frequently used in foodstuffs as
nutritionally or techno-functionally active ingredients.
There are protein preparations with a particularly high
protein value used as high-quality food additives (baby
food, special food, sports food). They are principally also
of interest for the formulation of feedstuff in which a
high protein availability has to be ensured. Other protein
preparations have a good techno-functionality and, e.g.,
are suitable to stabilize foams or emulsions or to form
gels. These protein preparations are primarily suited as
food ingredients and are also used for special feedstuffs
or technical purposes.
Principally, protein preparations of animal or plant origin
can be distinguished.
Examples of protein preparations of animal origin are such
made of hen's eggs, milk, whey or casein and gelatin
preparations from slaughterhouse waste. The disadvantage is
that such protein preparations have a characteristic
intrinsic taste and intrinsic odor and are therefore
limited to certain applications. They are often expensive
to produce and problematic with respect to allergies and
are rejected by certain consumers for ethical reasons.
As alternative protein sources of plant origin, primarily
preparations from soy proteins and wheat gluten are used.
However, the application range of the same in case of
foodstuffs and feedstuffs is limited, among other things
due to substances which affect the smell or taste and/or
are allergenic and/or due to dark color.
Likewise, plant protein preparations are known which are
produced from rape seeds in the form of rape seed
concentrates or rape protein isolates.
In comparison to rape protein concentrates, rape protein
isolates have a very high protein content which is at least
90 % based on the dry mass. However, rape protein
concentrates usually contain the entire amino acid spectrum
of the rape seed used during the production. They have a
balanced amino acid spectrum and are suitable, among other
things, for protein enrichment in foodstuffs and
feedstuffs.
The production of rape protein concentrates requires
special measures if components which are undesirable for
special applications such as glucosinolates, phenolic acids
and phytic acids have to be removed. For this purpose, an
extraction with diluted aqueous-alcoholic solutions has
been proposed. For example, in the literature, rape protein
concentrates are described which were obtained by
extraction with 45 % isopropanol (see Yumiko Yoshie-Stark
et al., "Functional and bioactive properties of rapeseed
protein concentrates and sensory analysis of food
application with rapeseed protein concentrates", LWT 39
(2006) 503-512) or with 80 % alcohol in connection with
high temperatures of 60 °C (see Kozlowska et al., "The
influence of selected technological processes on the
improvement of rapeseed meal and fluor feed quality. Part
1.", the Nahrung 35 (1991) 5, 485-489).
With these two methods, rape protein concentrates are
produced in that prior to the extraction, deoiling takes
place exclusively by means of solvents. After the
extraction of the non-protein substances, no further
treatments are provided. Said methods, among other things,
have the disadvantage that the functional properties of the
rape protein concentrates are difficult to be preset. Also,
in the above-mentioned article of Yumiko Yoshie-Stark et
al. it is reported that sausages for which the produced
rape protein concentrate was used showed a drastic color
deterioration.
Along with the extraction, preparing the rape seeds can
already be a problem if this is not carried out gentle
enough. In the magazine article of Felix H. Schneider and
Michael Rass, "Trennpressen geschalter Rapssaat -
Zielsetzung und verfahrenstechnische Probleme", Pett/Lipid
99 (1997) No. 3, 91-98, a method is described in which
dehulled rap seeds are deoiled by means of a screw press
and subsequently by means of hexane at a temperature of 60
degrees Celsius. No special measures are provided for a
gentle deoiling so that the proteins can be excessively
denatured.
In summary, the known rape protein concentrates which have
a low purification degree, are limited with respect to
their functionality and/or contain a certain proportion of
undesirable components which can negatively influence the
nutritional value, the color, the smell and/or taste of the
foodstuffs or groceries containing the same. Thus, the rape
protein concentrates have a limited application range and
can only be used in low concentrations.
Rape protein isolates as described e.g. in EP 1 513 415
B1, have a high purification degree and are therefore
complicated and expensive to produce. They contain only a
proportion of individual components of the original protein
matrix of the rape seed and thus have a specific
nutritional and techno-functional profile with few
particularly outstanding properties. Their application
spectrum is very specific and limited to few applications.
It is an object of the present invention to provide protein
preparations which are relatively inexpensive to produce
and can be used in many applications.
This object is solved with a protein preparation which is
defined in claim 1 or is produced with the method according
to the independent method claim. The further claims define
preferred embodiments of the protein preparation and the
method according to the invention as well as a product
produced with a protein preparation according to the
invention and a method for recovering energy from the rape
hulls produced during dehulling the rape seeds.
The protein preparation according to the invention has a
lower protein content than protein isolates and is suitable
for a more cost-effective production because a high
purification as it is required in case of protein isolates
can be avoided.
Surprisingly, despite the higher proportion of non-protein
substances, the protein preparation according to the
invention has properties which are similar to the ones of
the known rape protein isolates or are even more versatile
than the latter. Due to the bright color and the balanced
techno-functional spectrum in the form of water-binding,
oil-binding and emulsifying function, the protein
preparation can be used in many applications, amongst
others in foodstuffs and feedstuffs, for binding water
and/or oil, or for forming an emulsion. Said protein
preparation is suitable to replace other preparations which
were previously used for these functions and which are of
animal or plant origin such as hen's egg, milk, soy, rape
in the form of rape isolates, etc.
Further, surprisingly, if present in the form of rape
protein flour, which is particularly inexpensive to
produce, the protein preparation has properties with
respect to color and functionalities which allow to use the
rape protein flour in a plurality of foodstuff and
feedstuff applications.
The field of use of the protein preparation according to
the invention can be extended if the protein preparation is
free of the plant-inherent or seed-inherent flavors of the
rape, in particular if it is substantially odorless and/or
substantially tasteless. This prevents, among other things,
that when incorporating the protein preparation into the
foodstuffs and feedstuffs, an undesired change of taste and
flavor takes place.
Also, by obtaining a foam-forming functionality, the field
of use can be extended so that the protein preparation can
be used, e.g. as substitute for hen's egg white or other
foam-forming additives so as to produce foam-like
foodstuffs.
Preferably, the protein preparation has a low fat content,
whereby a good storage stability of the protein preparation
is ensured.
More preferably, the protein preparation has a low content
of phytic acid, glucosinolates and/or phenolic acid.
Thereby, the risk is reduced that during digestion, the
processing of nutrients is affected.
The method according to the invention allows a gentle
production of the preparation so that an undesired
denaturation of the proteins is prevented and allows to
obtain protein preparations of premium and high sensory
quality and a broad application spectrum.
If a partial deoiling is provided during the mechanical
deoiling, the treatment is particularly gentle and the
subsequent method steps can be simplified, e.g. by
eliminating a mechanical comminution prior to the
extraction.
If during the mechanical deoiling, an excessive temperature
is avoided, it is in particular possible to avoid
undesirable protein alterations or reactions of the non-
protein substances with the proteins.
During the production of a protein concentrate, a gentle
treatment can also be achieved by providing an extraction
in which the non-protein substances in the protein flour
are depleted. By subsequently preparing the grain size, the
functional properties of the protein concentrate can be
preset in an improved manner.
Preferably, the method is carried out such that the
extraction by means of the extraction solvent is carried
out in a plurality of extraction steps, wherein during at
least one transition from the one to the next extraction
step, the alcohol content in the extraction solvent is
increased. This allows to perform the subsequent drying
process in a particularly gentle manner because the content
of the residual water to be removed, which evaporates
slower and at a higher temperature than the alcohol, is
reduced.
An additional benefit in the form of energy recovery can be
achieved by burning up the hulls produced during dehulling
the rape seeds.
Further advantages arise from the features according to the
dependent claims and the following description in which the
invention is illustrated by means of exemplary embodiments.
Unless otherwise stated, the contents expressed below as
percentages are based in case of liquids on percent by
volume (v/v) at a temperature of 25 degrees Celsius and in
case of solids on percent by mass (w/w).
A) Production method
For example, the protein preparation according to the
invention can be produced from rape according to the
following method. For this, any rape can be used, even a
specifically farmed raped (e.g. of the type "00-rape", in
English "Canola") and/or a genetically modified one. The
method comprises the following method steps V1-V8:
V1 Pretreatment:
The rape seed is dried after harvesting at a product
temperature of less than 95 °C, preferred less than 4 0
°C for a heating time which lies typically in the range
of 10 - 20 min. A higher product temperature is
conceivable if the contact time is short, i.e. less
than 20 min and preferably less than 5 min. By the
drying process is achieved that the rape seed has a
water content of less than 9 % w/w, preferred less than
8 % w/w and particularly preferred less than 7 % w/w.
Furthermore, the drying process is specifically carried
out such that, on the one hand, enzymes which
subsequently would disturb the method or the quality
of the end product are inactivated and, on the other, a
denaturation of the storage protein, which represents
the main portion of the proteins, takes place to a
limited extent. Thus, by the inactivation of the
enzymes such as myrosinase, lipoxygenase and
polyphenoloxidase it can be prevented, among other
things, that subsequently, a release of odor and taste
active mustard oils, a fat cleavage and/or color change
takes place.
V2 Dehulling:
The rape seeds which consist of kernel and hulls are
dehulled by breaking-up in a mill and separating in an
air stream into a kernel-rich and a hull-rich fraction.
The dehulling process is configured such that the
kernel fraction used in the subsequent method step V3
has a hull content of less than 15 % w/w, preferred
less than 5 % w/w and particularly preferred less than
1 % w/w. If necessary, the dehulling process comprises
in addition a sieving of the rape seed or the fractions
and/or a further classifying of the fractions so as to
obtain a sufficiently purified kernel fraction.
V3 Mechanical treatment:
The kernel fraction is mechanically partially deoiled,
e.g. by means of a press, to a residual oil content of
10-30 % w/w, preferably 15-25 % w/w. The temperature Tm
of the kernel fraction averaged over the duration of
the pressing process lies below 80 °C, preferred below
60 °C. This does not exclude that the temperature of
the kernel fraction at a certain time and/or the local
temperature of individual kernels is higher than Tm. If
necessary, cooling is provided to dissipate the heat
which is generated during the mechanical deoiling, e.g.
due to the pressure during pressing. It is conceivable
to provide, alternatively or additionally to the
mechanical deoiling, a mechanical treatment in the form
of flaking.
V4 Solvent deoiling:
The pressing residue ("rapeseed cake") obtained in the
method step V3 is deoiled with n-hexane, iso-hexane or
another suitable solvent at temperatures below 90 °C,
preferably below 60 °C and the solvent is removed, e.g.
by means of flash deso1ventizing. The deoiled residue
has a residual content of oil of less than 6 % based on
the dry mass (determined according to the Caviezel
method) and is hereinafter also called rape protein
flour.
V5 Aqueous-alcoholic extraction:
The deoiled residue is treated with aqueous alcohol
with an alcohol content between 60 and 95 % v/v,
preferably between 7 0 and 80 % v/v. During the aqueous-
alcoholic extraction, the accompanying substances of
protein such as sugar, secondary plant substances, etc.
are depleted while the proteins for the most part do
not go into solution. (Accordingly, this method differs
from the production of rape protein isolates in which
the proteins are extracted from the fiber matrix and
are subsequently recovered from the solution, e.g. by
precipitation and/or a membrane process.) After the
extraction, the alcohol is removed, preferably by using
a vacuum at temperatures of maximum 60 °C and/or by
using alcohol vapor or water vapor for expelling the
alcohol at a temperature below 60 °C.
V6 Drying:
The protein concentrate obtained in method step V5 is
dried. The temperature is selected here, among other
things, depending on the residual water content and
lies typically in the range of 50 to 90 °C, preferred
below 70 °C and particularly preferred below 60 C°.
Optionally, drying is carried out using a vacuum.
V7 Optional mechanical separation:
If necessary, the protein concentrate obtained in the
method step V6 is classified and/or sieved so as to
modify the functional properties and/or the color and
to separate any present hull particles.
V8 Further preparation of the grain size:
The obtained protein concentrate is brought in such a
pourable form that it has a certain grain size. This is
carried out e.g.. by sieving, classifying, fine milling
or granulating the powder obtained in method step V6 or
V7. The finally obtained rape protein concentrate is
hereinafter also referred to as RPC.
It is possible to omit the method step V5 and to process
the deoiled residue obtained in method step V4 according to
the method steps V6, V7 and/or V8. Thereby, a protein
preparation in the form of rape protein flour (RPF) is
provided.
It was found that due to preparing the grain size according
to the aforementioned method step V7 or V8, a further
improvement of the properties of the protein preparation
and/or a specific setting of the functional properties can
be achieved. It was in particular found that the water-
binding properties and oil-binding properties as well as
the emulsifying properties change in different ways by fine
milling the rape protein flour or rape protein concentrate.
Thus, depending on the purpose of use, a higher water-
binding and oil-binding capability can be established by a
systematic milling and further properties such as
emulsifying capacity can be changed.
Further details of the method can be found in the
unpublished German Patent Application 10 2009 010 813.0,
filed on February 27, 2009, the content of which is hereby
included in full in the description of the present
application.
B) Characterization of the produced protein preparation
By means of the above-described production method, a
protein preparation can be obtained which is characterized,
e.g. with respect to protein isolates which are obtained by
aqueous fractionation and complex isolation methods, by a
balanced nutritional profile and a techno-functional
spectrum. The protein preparation is suitable, among other
things, as foodstuff or feedstuff additive even without
further processing, e.g. so as to obtain the high protein
content of a protein isolate. Surprisingly, although it is
not a protein isolate, the protein preparation shows the
techno-functional properties of protein isolates. It has
neutral, typically yellow color and is largely free of
sensorially disturbing and anti-nutritive accompanying
substances. In particular, in the form of rape protein
concentrate, it has almost no intrinsic odor and intrinsic
taste.
It is particularly surprising that already the deoiled rape
protein flour (RPF) has an extremely appealing color and a
well-developed functionality and is suitable for many
foodstuff and feedstuff applications.
Below, the following determination methods are used for the
quantitative characterization of the produced protein
preparations:
-Protein content:
The protein content is defined as the content which is
calculated from the determination of the nitrogen and the
multiplication of. the same by the factor 6.25. The
protein content can be expressed e.g. as a percentage
based on the dry mass (DM).
— Color:
Perceptible color is defined by means of CIE-L*a*b* color
scale (cf. DIN 6417). Here, the L*-axis indicates the
brightness, wherein black has the value 0 and white has
the value 100, the a*-axis describes the green or red
portion and the b*-axis describes the blue or yellow
portion.
- Protein solubility:
The protein solubility is determined by means of the
determination method according to Morr et al. 1985
(hereinafter called PN determination method), see
magazine article: Morr C.V., German, B., Kinsella, J.E.,
Regenstein, J.M., Van Buren, J.P., Kilara, A., Lewis,
B.A., Mangino, M.E, "A Collaborative Study to Develop a
Standardized Food Solubility Procedure. Journal of Food
Science", volume 50 (1985) pages 1715-1718).
With the PN determination method, the protein preparation
is suspended at room temperature in a mass-volume
proportion of 1:25 to 1:50 (w/v) (i.e. 1-2 g of the
protein preparation in 50 ml solution) in a 0.1 M NaCl
solution and, by using 0.1 M HC1 or NaOH solution, is
maintained at a pH value of pH 7 for approximately 60 min
and is stirred at approximately 200 rpm, and the
insoluble sediment is subsequently removed by
centrifuging for 15 min at 20,000 times gravity
(20,000g). The protein solubility can be expressed e.g.
as a percentage, wherein a protein solubility of x %
means that x % of the protein present in the preparation
are found again in the clarified supernatant when the PN
determination method is used.
- Water binding:
Water binding ability is defined by means of the
determination method (hereinafter called AACC
determination method) as specified in: American
Association of Cereal Chemists, "Approved methods of the
AACC". 10th ed., AACC. St. Paul, MN, 2000b; Method 56-20.
"Hydration capacity of pregelatinized cereal products".
Water binding ability can be expressed e.g. in ml/g DM,
i.e. milliliter bound water per gram of dry mass and is
determined according to the AACC determination method via
the weight of the sediment saturated with water less the
weight of the dry preparation after mixing approx. 2 g of
protein preparation with approx. 40 ml of water for 10
min and centrifugation at l,000g for 15 min at 20 6C.
- Oil binding:
Oil binding ability is defined by means of the
determination method (hereinafter called OB determination
method) as specified in: Ludwig I., Ludwig, E., Pingel
B., "Eine Mikromethode zur Bestimmung der
Fettbindkapazitat". Nahrung/Food, 1989, 33(1), 99.
The oil binding ability can be expressed e.g. in ml/g,
i.e. milliliter bound oil per gram of preparation and is
measured according to the OB determination method as
volume of the oil-binding sediment after mixing 1.5 g of
protein preparation with 15 ml of corn oil for 1 min and
centrifugation at 700g for 15 min at 20 °C.
- Emulsifying capacity:
Emulsifying capacity is determined by means of the
determination method (hereinafter called EC determination
method), wherein corn oil is added to a 1 % suspension of
the protein preparation of 100 ml, pH 7, until phase
inversion of the oil-in-water emulsion. Emulsifying
capacity is defined as the maximum oil absorption ability
of this suspension, determined via the spontaneous
decrease of the conductivity during the phase inversion
(cf. magazine article of Wasche, A., Mviller, K., Knauf,
U., "New processing of lupin protein isolates and
functional properties". Nahrung/Food, 2001, 45, 393-395)
and can be expressed e.g. in ml/g, i.e. milliliter of
emulsified oil per gram of preparation.
- Foam activity:
Foam activity is expressed as a percentage, measured as
volume increase of a 5 % solution, pH 7, when beating for
8 min at setting 3 (591 rpm) in a Hobart 50N standard
kitchen machine (steel container with a capacity of 5
liters) with a beater (wire beater).
- Foam density:
Foam density is expressed in g/l, i.e. mass of the foam
per volume unit, and is measured after beating a 5 %
solution, pH 7, for 8 min at setting 3 (591 rpm) in a
Hobart 50N standard kitchen machine (steel container with
a capacity of 5 liter) with a beater (wire beater).
- Foam stability:
Foam stability is expressed as a percentage, measured as
volume decrease of 100 ml of foam within one hour after
beating a 5 % solution, pH 7, for 8 min at setting 3 (591
rpm) in a Hobart 5ON standard kitchen machine (steel
container with a capacity of 5 liter) with a beater (wire
beater).
- Fat content:
Fat content is determined after sample disintegration and
saponification of the fatty acids e.g. according to the
Caviezel method (described in DGF. "Method of Caviezel",
DGF K-I 2c (00). In: DGF-Einheitsmethoden, Deutsche
Gesellschaft fur Fettwissenschaften e.V., Munster, WVG,
Stuttgart, 2nd edition, 2004.).
- Denaturation:
Denaturation is expressed as a percentage and is measured
e.g. by comparing the denaturation properties of the main
protein fraction of the rape kernels before and after
heating by means of "Differential Scanning Calorimetry",
as described in the magazine article: Sousa, I.M.N.,
Mitchell, J.R., Ledward , D.A., Hill, S.E., Beirfio da
Costa, M.L., "Differential Scanning Calorimetry of lupin
and soy proteins". Zeitschxift fur
Lebensmitteluntersuchung und -Forschung, volume 2 01
(1995), 566-569.
- For comparison purposes, the following commercially
produced products were used:
- pea protein isolate Pisane® (produced by Cosucra),
- soy protein isolate SUPRO® EX33 (produced by DuPont) ,
- sodium caseinate (spray-dried), FN5S from Rovita.
With the production method according to the invention,
protein preparations can be produced which typically have
the following properties:
Appearance:
- In pourable form e.g. as flakes, granulate, powder or in
the form of other particles.
- The color is white to cream, light gray or light yellow
to deep yellow, possibly with a portion of dark-colored
particles of maximum 5 % w/w, preferably less than 2 %
w/w. The brightness L* according to CIE-L*a*b* color
scale yields a value of at least 70, L* >= 70. The
following are typical values for L*, a* and b*:
L* >= 80, -5 < a* < +5, -5 < b* < +30; preferably
L* >= 85, -l < a* < +5, 0 < b* < +25; particularly
preferred
L* >= 90, -1 < a* < +3, 0 < b* < +20.
Composition:
- The protein content is less than 90 % in the dry mass
(DM) and/or less than 80 % based on DM. Typically, the
protein content lies between 40 and 70 % based on DM
and/or between 45 and 65 % based on DM.
- Crude fiber content between 3 and 20 % based on DM,
preferred between 5 and 10 % based on DM.
- The content of total dietary fibers is typically
20-40 %, the content of insoluble dietary fibers/ADF
("Acid detergent fiber") is typically 8-20 %.
- Pat content, determined e.g. by gravimetric analysis
after Soxhlet extraction, typically less than 6 % based
on DM, preferred less than 1 %.
- Sugar content less than 10% based on DM, preferred less
than 5 %, particularly preferred less than 2 %.
- Content of harmful substances, in particular anti-
nutritive substances:
• Phytic acid content less than 10 % based on DM,
preferred less than 5 %, particularly preferred less
than 3 %.
• Glucosinolate content (content of mustard oil
compounds) less than 4000 mg per kg of protein
preparation, preferred less than 2500 mg/kg,
particularly preferred less than 150 0 mg/kg. In
particular, the progoitrin content is less than 10 00
mg/kg, preferred less than 500 mg/kg, particularly
preferred less than 200 mg/kg.
• Phenolic acid content (determined as sinapinic acid)
less than 5 % based on DM, preferred less than 2 %,
particularly preferred less than 0.5 %.
- Lignin content less than 6 % based on DM, preferred less
than 4 %, particularly preferred less than 3 %.
- In general, the protein content as well as the lignin
content of the rape protein flour (RPF) is lower than
the one of the rape protein concentrate (RPC) produced
therefrom, whereas the content of fat, sugar and
phenolic acid in RPF is higher than the one in RPC.
- The amino acid composition is balanced with a high
protein value compared to commercially available plant
protein concentrates, wherein the lysine content with
regard to the total protein is at least 4 %, preferred
at least 5 % and the content of sulfur-containing amino
acids (sum of methionine and cysteine) with regard to
the total protein is at least 3 %, preferred at least
4 %. The original amino acid composition of rape seed is
substantially maintained in case of the protein
preparation.
- The denaturation is typically in the range of 5 % to
40 % and/or in the range of 10 % to 20 %.
Techno-functional properties:
- Protein solubility:
The protein solubility, determined according to the PW
determination method, is greater than 40 %, preferred
greater than 60 %.
Typically, the protein solubility in case of the RPF is
in the range of 60-70 % and in case of the RPC in the
range of 45-55 %.
- Water binding:
The water binding ability, determined according to the
AACC determination method, is at least 1 ml/g DM,
preferred at least 2 ml/g DM and particularly preferred
at least 3 ml/g DM. Comparison measurements show that the
water binding ability of the preparation is typically at
least 30 % of the water binding ability of Pisane®,
determined according to the AACC determination method.
- Oil binding:
The oil binding ability, determined according to the OB
determination method, is at least 1 ml/g, preferred at
least 2 ml/g and particularly at least 4 ml/g. Comparison
measurements show that the oil binding ability is at
least 100 % of the oil binding ability of Pisane® or
Supro® EX33, determined according to the OB determination
method.
- Emulsifying capacity:
The emulsifying capacity, determined according to the EC
determination method, is at least 400 ml/g, preferred at
least 500 ml/g, particularly preferred at least 600 ml/g.
Comparison measurements show that the emulsifying
capacity is at least 40 % of the emulsifying capacity of
sodium caseinate FN5S, determined according to the EC
determination method. The emulsifying capacity is
typically higher in case of the RPF than in case of the
RPC produced therefrom.
- Foam forming properties:
• Foam activity:
The foam activity is at least 500 %, preferably at
least 1000 %. Comparison measurements with fresh
hen's egg whites beaten for 3 min on setting 3 in a
Hobart 50N standard kitchen machine with a beater
show that the foam activity of the protein
preparation corresponds to at least 30 % or even at
least 60 % of the foam activity of hen's egg white.
• Foam density:
The foam density lies in the range of 80 and 110
g/l. Comparison measurements with whipped hen's egg
whites beaten for 3 rain on setting 3 in a Hobart 50N
standard kitchen machine with a beater show that the
foam density lies in the range of 80 and 110 % of
the foam density of whipped egg white.
• Foam stability:
The foam stability is at least 80 %, preferably at
least 90 %. It corresponds typically to at least
90 % of the foam stability of whipped hen's egg
white, measured as volume decrease of 100 ml whipped
egg white within one hour after beating for 3 min on
setting 3 in a Hobart 5ON standard kitchen machine
with a beater.
Sensory properties:
In addition to the bright color, the protein preparation,
in particular in the form of the RPC, is substantially
odorless and tasteless. In particular, the plant or seed
flavors of the rape are substantially missing. Thus,
substantially, no mustard-like, horseradish-like or pungent
odor and taste as well as substantially no bitter taste can
be sensed.
Sensory tests in which skilled examiners compare a
particular taste or flavor impression of the protein
preparation and a suitable reference substance and evaluate
it on a scale of 1 to 10 (1 = not sensible, 10 = strongly
sensible), wherein the reference substance is selected such
that its taste or flavor impression to be tested is
evaluated with at least 8, show that a value of 3 or less
(typically a value of 1) is assigned to the protein
preparation.
Examples for taste or flavor impressions to be tested are:
- horseradish-like/pungent odor and taste compared to
customary commercially available quality horseradish,
e.g. "Meerrettich" from Hengstenberg,
- mustard-like odor and taste compared to a commercially
available quality mustard, e.g. "Lowensenf medium",
- bitter taste compared to a 0.1 % aqueous caffeine
solution,
- astringency (rough, numb mouth feel) compared to a tart
red wine or bitter chocolate.
Color, intrinsic taste and intrinsic odor of the protein
preparation in the form of the RPC are such that when
incorporating it into foodstuffs and feedstuffs,
substantially, no significant change determined with
statistical methods and to be evaluated as being negative
of the characteristic appearance, odor or taste of the
finished preparation occurs.
Sensory tests show that the taste and flavor change in a
food product caused by the use of the protein preparation
is limited with respect to a food product without the
protein preparation to such an extent that a skilled
examiner can sense a deviation of one of the above-
mentioned taste or flavor characteristics (horseradish,
mustard, etc.), on a scale of 1-10, of maximum 3 levels or
even maximum 1 level (deviation almost not sensible
anymore).
C) Examples
In the following, production method and protein preparation
according to the invention are illustrated by means of
further examples.
C.1) Example 1: Rape protein flour and rape protein
concentrate from 90 % dehulled rape seeds.
Production:
1. Dehulling the rape seeds by breaking-up in an impact
mill and separating into a kernel-rich and a hull-rich
fraction in the air stream.
2. Sieving the coarse fractions with a sieve of mesh size
1.25 mm so as to remove dehulled kernels and to obtain
a purified kernel fraction after passage through the
sieve. (In this example, the kernel fraction contains
a hull content of approx. 10 % w/w).
3. Flaking the purified kernel fraction by means of
smooth-rolling so as to obtain rape flakes.
4. Deoiling the rape kernel flakes in the Soxhlet at
temperatures of maximum 80 °C, primarily below 60 °C.
5. Removing the solvent in the air stream at room
temperature. The raffinate obtained in this manner
results in the rape protein flour mentioned below.
6. Three-fold extraction of the rape protein flour with
the 10-fold volume e.g. of a 80 % (v/v) isopropanol
solution at room temperature in each case for 1 h
while stirring and separating the extract via a filter
cloth.
7. After the third extraction, the solvent residues are
removed by air drying.
8. Milling the raffinate obtained in the above method
step 7 in a pin mill with a sieve insert of 1 mm.
9. Secondary drying of the raffinate in a vacuum at
maximum 50 °C.
10. Sieving the raffinate with a sieve of mesh size 315
micrometer so as to obtain a rape concentrate in the
form of a fine powder.
Properties:
The rape protein concentrate obtained in this manner has a
protein content of more than 55 % in DM. The composition is
listed in the table 1 below; some functional properties are
listed in the tables 2 and 3 below. These three tables also
include the values for the protein preparation in the form
of the rape protein flour obtained in the aforementioned
method step 5.
By varying the type of alcohol (methanol, ethanol,
isopropanol) and the alcohol content (e.g. 70, 80, 90 %
v/v) in the above-mentioned method step 6, similar protein
preparations were produced according to the same method.
The color of these different rape protein concentrates was
determined according to CIB-L*a*b* resulting in the
following mean values and standard deviations:

C.2 Example 2: Rape protein flour and rape protein
concentrate from 100 % dehulled rape seeds.
Production:
1. Dehulling the rape seeds by breaking-up in an impact
mill and separating into a kernel-rich coarse fraction
and a hull-rich fine fraction in the air stream.
2. Sieving the coarse fractions with a sieve of mesh size
1.25 mm so as to remove dehulled kernels and to obtain
a pre-purified kernel fraction after passage through
the sieve.
3. Sorting out of hull particles and unhulled kernels
from the pre-purified kernel faction by color sorting
so as to obtain a pure kernel fraction. Accordingly,
the kernel fraction is almost free of hulls.
4. Flaking the kernel fraction in the roller mill with
two counter-rotating smooth rolls which have a gap of
0.5 mm therebetween.
5. Deoiling the rape flakes with n-hexane in the Soxhlet
at temperatures of maximum 80 °C, primarily below
60 °C.
6. Removing the solvent in the air stream at room
temperature. The raffinate obtained in this manner
results in the rape protein flour mentioned below.
7. Three-fold extraction of the rape protein flour with
the 10-fold volume e.g. of a 70 % (v/v) ethanol
solution at room temperature in each case for 1 h
while stirring and separating the extract via a filter
cloth.
8. Two-fold extraction of the raffinate obtained in the
method step 7 with 10 0 % ethanol so as to increase the
alcohol concentration in the raffinate to at least
90 %.
9. Evaporating the alcohol and drying the raffinate
obtained in the method step 8 in the rotary evaporator
in a vacuum at maximum 50 °C so as to obtain a rape
protein concentrate.
10. Milling the rape protein concentrate in a pin mill
with sieve insert 0.5 mm so as to obtain the rape
protein concentrate in the form of fine powder.
Properties:
The rape protein concentrate obtained in such a manner is a
fine, bright powder with a protein content of more than
55 % in DM. The composition is listed in table 1; some
functional properties are listed in table 2. These two
tables also include the values for the rape protein flour
obtained in the above-mentioned method step 6.
The rape protein concentrate obtained in such a manner is
free of rape-inherent or mustard- and horseradish-like
flavor components.
The color of the hull-free rape protein flour obtained in
method step 6 and the rape protein concentrate obtained in
method step 10 is particularly appealing, i.e. neutral and
has the following values according to CIE-L*a*b*:

C.3 Example 3: Rape protein flour and rape protein
concentrate from dehulled rape seeds
Production:
1. Dehulling the rape seeds by breaking-up in an impact
mill and separating into a kernel-rich coarse fraction
and a hull-rich fine fraction in the air stream in a
zigzag classifier (classifier with particularly good
selectivity, wherein the channel in which the air
stream rises is divided by walls arranged in zigzags
into a plurality of small tubes).
2. Sieving the coarse fraction with a tumbler sieve of
mesh size .1.5 mm so as to remove unhulled kernels and
to obtain a purified kernel fraction after passage
through the sieve.
3 . Flaking the kernel fraction into "rape kernel flakes"
in the roller mill with two counter-rotating smooth
rolls which have a gap of 0.3 mm therebetween at
temperatures below 30 °C.
4. Deoiling the rape kernel flakes with iso-hexane in a
percolator at temperatures of maximum 60 °C.
5. Expelling the hexane with superheated hexane vapor in
a vacuum (< 500 mbar).
6. Expelling further hexane with superheated water vapor
in a vacuum (< 500 mbar).
7. Removing solvent residues by heating to 60 °C in a
vacuum (< 500 mbar). The raffinate obtained in such a
manner is hereinafter referred to as protein flour.
8. Three-fold extraction of the protein flour with the 5-
8-fold mass of a 65 % (w/w) ethanol solution at room
temperature by circulating the solvent until constancy
of the density and separating the extract via a sieve
bottom.
9. Two-fold extraction of the raffinate with 94 % w/w of
ethanol so as to increase the alcohol concentration in
the raffinate to at least 90 % w/w.
10. Evaporating the alcohol and drying the raffinate
obtained in such a manner by heating to 50-60 °C in a
vacuum (< 300 mbar) so as to obtain a protein
concentrate.
11. Milling the protein concentrate in a pin mill with
sieve insert 0.5 mm so as to obtain the protein
concentrate in the form of a fine powder.
Properties:
The rape protein concentrate obtained in such a manner is a
fine bright powder with a protein content of > 60 % in DM.
The composition is listed in table 1 of section D; some
functional properties are listed in the tables 2 and 3.
The protein concentrate obtained in such a manner is low in
rape-inherent or mustard- and horseradish-like flavor
components.
The color of the rape protein flour (RPP) produced in such
a manner which is low in hulls and the color of the rape
protein concentrate is particularly appealing or neutral
and is represented according to CIE-L*a*b* with the
following values:

C.4) Example 4: Rape protein flour and rape protein
concentrate with specific properties
In this example, among other things, the modification of
the functional properties of the rape protein preparation
was investigated during a final preparation of the grain
size.
Production:
1. Dehulling the rape seeds by breaking-up in an impact
mill and separating into a kernel-rich coarse fraction
and a hull-rich fine fraction in the air stream in a
zigzag classifier.
2. Sieving the coarse fraction with a tumbler sieve of
mesh size 1.5 mm so as to remove unhulled kernels and
to obtain a purified kernel fraction after passage
through the sieve.
3. Flaking the kernel fraction in the roller mill with
two counter-rotating smooth rolls which have a gap of
0.3 mm therebetween at temperatures below 3 0 °C.
4. Deoiling the rape kernel flakes with iso-hexane in a
percolator at temperatures of maximum 60 °C.
5. Expelling the hexane with superheated hexane vapor in
a vacuum (< 500 mbar).
6. Expelling further hexane with superheated water vapor
in a vacuum (< 500 mbar).
7. Removing solvent residues by heating to 60 °C in a
vacuum (< 500 mbar). The raffinate obtained in such a
manner is hereinafter referred to as protein flour.
8. Classifying, sieving and/or milling the protein flour
in a pin or impact mill so as to obtain fractions with
different hull content and/or different particle size
distribution and to modify the functional properties
in this manner. The setting of the mills is specified
in table 4 in section D.
9. Three-fold extraction of the protein flour with the 5-
8-fold mass of a 65 % (w/w) ethanol solution at room
temperature by circulating the solvent until constancy
of the density and separating the extract via a sieve
bottom.
10. Two-fold extraction of the raffinate with 94 % w/w of
ethanol so as to increase the alcohol concentration in
the raffinate to at least 90 % w/w
11. Evaporating the alcohol and drying the raffinate
obtained in such a manner by heating to 50-60 °C in a
vacuum (< 300 mbar) so as to obtain a protein
concentrate.
12. Classifying, sieving and/or milling the protein
concentrate in a pin or impact mill (setting see table
4) so as to obtain fractions with different hull
content and/or different particle size distribution
and to modify the functional properties in this
manner.
By preparing the grain size as carried out above in step 8
or step 12, the functional properties of the protein
preparation could be changed. For reducing the grain size,
besides a pure milling process, a classification or a
sieving process, if necessary in connection with a milling
process was used. As shown in table 4, with decreasing
grain size, water binding tends to increase as well as the
emulsifying capacity in case of the rape protein
concentrate, whereas oil binding decreased slightly or
remained nearly unchanged. As further shown in table 4,
preparations with a more homogenous grain size distribution
have a higher water binding ability. The combination of
fractioning and comminuting was found to be particularly
advantageous for increasing water binding. In summary, it
is still present in the form of the pellets and
corresponds with respect to its composition to the
protein flour in example 1.
5. Extracting the protein flour pellets from step 4
without further comminution by treating them with an
ethanol solution using the percolation method with
recirculation of the solvent until the solvent does
not change anymore.
6. Repeating step 5 with fresh solvent.
7. Further treatment as in example 1, steps 7-9.
8. Use of the finished protein concentrate with or
without subsequent comminution.
In this example 5, the rape kernels were present after
dehulling in such a form that it was immediately possible
to mechanically deoil them. A prior comminution or flaking
was not carried out.
Deoiling by pressing was carried out during step 2 with a
screw press. At an exit temperature of approx. 40 °C, round
press cake pellets with a fat content of 23 % w/w (25 % in
DM) were obtained at the nozzle outlet of the screw press
which had a high porosity and a good cohesion and a
mechanical stability so that they could be used immediately
for deoiling and were just strong enough to not fall apart
during deoiling. At a higher pressing degree set for a
residual fat content of approx. 17 % w/w, these pellets
were slightly denser and stronger and had a higher
mechanical strength but could still be broken apart with
moderate force. At a further increased pressing degree set
for lower fat contents, the pellets were very strong and
stable and could be broken only by means of, e.g., a mill.
Furthermore, it was found that when the pressing degree was
too high, the pellets had a dark discoloration which leads
to the conclusion of undesirable damages to the protein and
would impair the color of the protein preparation.
It was found that at a pressing degree set for a residual
fat content in the range of typically approx. 17 % to 25 %
w/w residual fat, press cake pellets are obtained which
have a good mechanical stability at a still sufficient
porosity so that without further structuring or comminution
during the subsequent extraction, a complete deoiling is
possible.
Surprisingly, despite the loosening of the structure
resulting from the removal of the oil, even after deoiling,
the pellets still have a sufficient mechanical stability so
that they can be subjected to an extraction with a further
solvent and thus can be cleaned from non-protein substances
without falling apart. Due to the porous structure, the
pellets have a very favorable extraction behavior for the
further extraction with alcoholic solution.
In summary, in a pressing process in which a certain
residual fat content is maintained, the particles can be
structured in such a manner that a subsequent structuring
or comminution which usually is carried out for breaking
the press cake is no longer required. Besides simplifying
the method, this contributes to the conservation of the
press cake so that, among other things, the protein
functionality and the color in the end product can be
improved.
Also, by the reduced pressing degree, the proteins are
treated with care and the functional properties of the
protein preparation are maintained in an improved manner.
At the same time, a particle shape is produced which allows
an optimal extraction and thus, the residual oil content
can be further reduced after deoiling. This too, among
other things, contributes to an improvement of the color of
the protein preparation.
D) Tables
Table 1: Composition of the rape protein preparation from
the examples 1 to 3 in comparison to reference products.
The listed values for the content of proteins, ash, fat and
glucose are based on the dry mass (DM). The protein content
was determined by determining the nitrogen by means of the
Dumas method and multiplication by the factor 6.25. The ash
was determined by TGA determination at 950 °C. The listed
fat content includes phospholipids according to Caviezel.
The glucose content was determined photometrically after
one extraction.
Table 2:
Functional properties of the rape protein preparations from
the examples 1 to 3 in comparison to reference products.
For analyzing the functional properties, the preparations
were milled in a laboratory impact mill with sieve insert
500 µm.
Table 3:
Foam-forming functions of the rape protein preparations
from the examples 1 and 3 compared to fresh hen's egg
white. For analyzing the foam-forming properties, the
preparations were milled in a laboratory impact mill with
sieve insert 500 µm.
Table 4 :
Functional properties of rape protein flours (RPF) and rape
protein concentrates (RPK) which are prepared with
different grain sizes. The columns S1-S2 have the following
meaning:
S1: Grain size of the finished protein preparation in
micrometer.
S2: Homogeneity, wherein "0" means a wide distribution, "+"
a narrower, "++" an even narrower and "+++" a very-
narrow grain size distribution.
S3: Water binding ability in ml/g (DM)
S4: Oil binding ability in ml/g
S5: Emulsifying capacity in ml/g
Empty boxes in the columns S1-S2 mean that the
corresponding value has not been determined.
From the preceding description, numerous modifications are
at the disposal of the skilled person without departing
from the scope of the invention which is defined by the
claims.
Thus, e.g., it is conceivable to use the protein
preparation according to the invention as basic material
for producing a protein isolate which has a protein content
of at least 90 % in DM. The production is carried out e.g.
by means of aqueous extraction of the proteins.
Further, it is conceivable to prepare the hull fractions
produced during dehulling in such a manner that they can be
utilized energetically so as to generate electricity and/or
usable heat. Preparing the hull fractions can take place,
among other things, in such a manner that the hulls are
deoiled e.g. by pressing and/or by means of solvent, and/or
are pelletized. Energy recovery can be carried out, e.g. by
burning.
If necessary, wood and/or a different kind of suitable
biomass is added to the hulls so as to improve the burning.
Said biomass can also originate from the preparation of the
rape seeds before they are being dehulled and can be, e.g.,
in the form of impurities during raw material supply
(debris, contaminants, etc.) and/or in the form of
undersized and oversized grains (portion of the rape seeds
which is removed prior to dehulling so as to obtain rape
seeds for dehulling with a size as uniform as possible).
Preferably, rape components originating from kernels
produced during dehulling the rape seeds or from fractions
obtained from these kernels are not or only to a limited
extent added to the hulls to be burnt so that the ratio of
the mass of rape components to the mass of hulls is smaller
than 1 to 1, preferred smaller than 1 to 2 and particularly
preferred smaller than 1 to 5.
E) Glossary:
mg: milligram
ml: milliliter
RPC: rape protein concentrate
RPF: rape protein flour
DM: dry mass
Percent v/v ("volume per volume"): percent by volume,
determined at a temperature of 25 degrees Celsius (volume
fraction of a component with respect to the volume of a
mixture)
Percent w/w ("weight per weight"):
Percent by mass/percent by weight
Patent claims
1. A protein preparation produced from rape seeds, having
a protein content of less than 90 % based on the dry mass,
characterized in that
the protein preparation has a brightness L*,
determined according to CIE-L*a*b* color scale, of at least
70 and that
the protein preparation has at least water-binding,
oil-binding and emulsifying functionality.
2. The preparation according to claim 1, wherein the
brightness L* is at least 80, preferably at least 85 and
particularly preferred at least 90, and/or
the values for a* and b* according to CIE-L*a*b* color
scale lie in the range of
-5 < a* < +5, -5 < b* < + 30, preferably in the range of
-1 < a* < +5, 0 < b* < +2 5 and particularly preferred in
the range of -1 < a* < +3, 0 < b* < +20.
3. The protein preparation according to any one of the
preceding claims, wherein the water binding ability of the
protein preparation, determined according to the AACC
determination method, is at least 1 ml per gram of dry
mass, preferred at least 2 ml per gram of dry mass and
particularly preferred at least 3 ml per gram of dry mass,
and/or
the oil binding ability, determined according to the
OB determination method, is at least 1 ml/g, preferred at
least 2 ml/g, and/or
the emulsifying capacity, determined according to the
EC determination method, is at least 400 ml/g, preferred at
least 500 ml/g, particularly preferred at least 600 ml/g.
4. The protein preparation according to any one of the
preceding claims, wherein the protein preparation has a
protein solubility which, determined according to the PN
determination method, is greater than 40 %, preferred
greater than 60 %.
5. The protein preparation according to any one of the
preceding claims, wherein the protein preparation is
substantially free of mustard-like and/or horseradish-like
odor and/or taste, and, preferably, the protein preparation
is substantially odorless and/or substantially tasteless
and/or causes substantially no astringency in case of oral
intake.
6. The protein preparation according to any one of the
preceding claims, wherein the protein preparation has in
addition foam-forming functionality.
7. The protein preparation according to claim 6, wherein
the protein preparation has at least one of the following.
foam-forming properties:
- the foam activity corresponds to at least 30 %,
preferred at least 50 % of the foam activity of hen's
egg white,
- the foam density corresponds to at least 50 % and/or not
more than 200 % of the foam density of whipped egg
whites,
- the foam stability corresponds to at least 80 %,
preferred at least 90 % and particularly preferred at
least 100 % of the foam stability of whipped egg white.
8. The protein preparation according to any one of the
preceding claims, wherein the protein content based on the
dry mass is at least 40 %, preferred at least 45 %, and/or
not more than 80 %, preferred not more than 70 %,
particularly preferred not more than 65 %:
9. The protein preparation according to any one of the
preceding claims, wherein the protein preparation has a
crude fiber content which, based on the dry mass, is at
least 3 %, preferred at least 5 %, and/or not more than
30 %, preferred not more than 20 % and particularly
preferred not more than 10 %.
10. The protein preparation according to any one of the
preceding claim, wherein the protein preparation has a fat
content which, based on the dry mass and determined
according to Caviezel, is less than 6 %, preferred less
than 5 %, particularly preferred less than 3 %.
11. The protein preparation according to any one of the
preceding claims, wherein the protein preparation has at
least one content, preferred all of the following contents
of substances:
- phytic acid content, based on the dry mass, of less than
10 %, preferred less than 5 %, particularly preferred
less than 3 %,
- glucosinolates content of less than 4000 mg per kg of
protein preparation, preferred less than 2500 mg/kg,
particularly preferred less than 1500 mg/kg,
- progoitrin content of less than 1000 mg per kg of
protein preparation, preferred less than 500 mg/kg,
particularly preferred less than 200 mg/kg,
- phenolic acid content, based on the dry mass, of less
than 5 %, preferred less than 2 %, particularly-
preferred less than 0.5 %.
12. The protein preparation according to any one of the
preceding claims, wherein the protein preparation has an
amino acid composition which corresponds substantially to
the one of the rape seeds used for the production.
13. A method for producing a protein preparation from rape
seeds, comprising the following steps:
dehulling the rape seeds so as to obtain a kernel
fraction,
mechanically treating the kernel fraction, wherein the
shape of the kernels is changed, and
- solvent-deoiling the mechanically treated kernel
fraction by means of solvent so as to obtain a protein
flour,
characterized by at least one of the following steps A to
C:
A) the mechanical treatment comprises a mechanical
deoiling in which a portion of the oil is separated so that
the mechanically deoiled kernel fraction has a residual oil
content of at least 10 % w/w;
B) the mechanical treatment comprises a mechanical
deoiling by pressing the kernel fraction, wherein the
temperature Tm of the kernel fraction averaged over the
duration of the pressing process lies below 80 degrees
Celsius;
C) in order to obtain a protein concentrate, an
extraction is carried out in which the non-protein
substances are depleted by means of an extraction solvent
from the protein flour and the proteins remain largely
undissolved, wherein the protein concentrate obtained after
the extraction is prepared with respect to the grain size
so as to obtain a pourable material having a predetermined
particle size distribution.
14. The method according to claim 13, wherein the kernel
fraction used for the mechanical treatment has a hull
content of less than 15 % w/w, preferred less than 5 % w/w
and particularly preferred less than 1 % w/w.
15. The method according to any one of the claims 13 to
14, wherein the mechanical treatment comprises flaking
and/or pressing the kernels.
16. The method according to any one of the claims 13 to
15, wherein the mechanical deoiling is carried out at a
temperature Tm which is averaged over the duration of the
pressing process and lies below 60 degrees Celsius.
17. The method according to any one of the claims 13 to
16, wherein the solvent-deoiling is carried out at a first
temperature and subsequently, the solvent is removed at a
second temperature, wherein the first temperature lies
below 90 degrees Celsius, preferred below 60 degrees
Celsius, and/or wherein the second temperature lies below
90 degrees, preferred below 70 degrees Celsius.
18. The method according to any one of the claims 13 to
17, wherein the mechanical deoiling is a partial deoiling
so that the mechanically deoiled kernel fraction has a
residual oil content of at least 15 % w/w and/or not more
than 35 % w/w, preferred not more than 25 % w/w and
particularly preferred not more than 20 % w/w.
19. The method according to any one of the claims 13 to
18, wherein in step C an aqueous-alcoholic extraction
solvent is used and the extraction is carried out in a
plurality of extraction steps, wherein during at least one
transition from the one to the next extraction step, the
alcohol content in the extraction solvent is increased.
20. The method according to any one of the claims 13 to
19, wherein the extraction by means of the extraction
solvent is carried out at a third temperature of less than
60 degrees Celsius and subsequently, the extraction solvent
is removed at a fourth temperature, wherein the third
temperature is preferably selected to be greater than 15
degrees Celsius and/or less than 40 degrees Celsius.
21. The method according to any one of the claims 13 to
20, wherein the extraction solvent is an aqueous-alcoholic
solvent which has an alcohol content of more than 0.5 liter
alcohol per liter extraction solvent, i.e. 50 % v/v,
preferred at least 60 % v/v and particularly preferred at
least 70 % v/v.
22. The method according to any one of the claims 13 to
21, wherein preparing the grain size in step C is carried
out by at least one of the following method steps: Milling,
granulating, sieving, classifying.
23. The method according to any one of the claims 13 to
22, wherein the protein flour obtained after deoiling, the
protein concentrate obtained after the extraction or both
are prepared with respect to the grain size so as to obtain
a pourable material, in particular powder or granulate,
having a predetermined grain size distribution.
24. The method according to any one of the claims 13 to
23, wherein the rape seeds are dried prior to dehulling so
as to reduce the water content, inactivate enzymes and/or
effect a defined denaturation in the main portion of the
protein.
25. The method according to claim 24, wherein the dried
rape seeds have a water content of less than 9 % w/w,
preferred less than 8 % w/w and particularly preferred less
than 7 % w/w.
26. The method according to any one of the claims 13 to
25, wherein the method is configured for obtaining a
protein preparation according to any one of the claims 1 to
12.
27. A product in the form of a rape protein flour, a rape
protein concentrate, a protein isolate having a protein
content of at least 90 % based on the dry mass, a
foodstuff, a feedstuff, in particular fish food, an
ingredient for foodstuff and/or feedstuff, a product for
technical applications or a cosmetic product, produced with
a protein preparation according to any one of the claims 1
to 12 and/or with a protein preparation obtainable with the
method according to any one of the claims 13 to 26.
28. A method for recovering energy from hulls which are
produced during dehulling of rape seeds, in which method
the hulls are prepared and burnt.
29. The method according to claim 28, wherein no further
rape components originating from the kernels obtained
during dehulling the rape seeds or from fractions obtained
from said kernels are added to the hulls to be burnt, or
such rape components are added to the hulls to an extent
that the ratio of the mass of the rape components to the
mass of the hulls is smaller than 1 to 1, preferred smaller
than 1 to 2 and particularly preferred smaller than 1 to 5.
30. The method according to any one of the claims 28 to
29, wherein the hulls are prepared by deoiling them by
pressing and/or by means of a solvent, and/or by pelleting
them.
31. The method according to any one of the claims 28 to
30, which method is carried out together with the method
according to any one of the claims 13 to 26.

The protein preparation produced from rape seeds has a
protein content of less than 90 % based on the dry mass,
has a brightness L*, determined according to CIE-L*a*b*
color scale, of at least 70 and also has at least water-
binding, oil-binding and emulsifying functionality. The
method for producing a protein preparation includes
dehulling the rape seeds and a mechanical deoiling process,
wherein only part of the oil is separated and/or wherein
the process is carried out at a temperature, averaged over
the duration of the pressing process, of less than 80 °C,
and/or an extraction process wherein the amount of non-
protein material is reduced in the protein flour and then
the grain size is prepared in order to obtain a pourable
material having a predetermined particle size distribution.