Patent Application
20110301074
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.”, Die 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 geschälter Rapssaat—Zielsetzung and verfahrenstechnische Probleme”, Fett/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).
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:
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 Feb. 27, 2009, the content of which is hereby included in full in the description of the present application.
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:
Color:
Protein Solubility:
Water Binding:
Oil Binding:
Emulsifying Capacity:
Foam Activity:
Foam Density:
Foam Stability:
Fat Content:
Denaturation:
With the production method according to the invention, protein preparations can be produced which typically have the following properties:
Composition:
Protein Solubility:
Water Binding:
Oil Binding:
Emulsifying Capacity:
Foam Forming Properties:
Foam Activity:
Foam Density:
Foam Stability:
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:
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).
In the following, production method and protein preparation according to the invention are illustrated by means of further examples.
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 CIE-L*a*b* resulting in the following mean values and standard deviations:
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*:
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 (RPF) 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:
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.
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 possible to modify the functional profile by a target-oriented preparation of the grain size distribution.
In the examples 1 to 4, flaking was selected as mechanical pretreatment by means of which the kernels were brought into an advantageous form for the subsequent treatment. After this, the kernel fraction was deoiled solely by using a solvent. A prior mechanical deoiling was not carried out. However, it is advantageous to provide the latter if protein preparations are to be produced in a particularly cost-effective manner and/or in larger volumes. Further advantages of mechanical deoiling arise from the example 5 described below.
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.
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.
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
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 010 813.0 | Feb 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CH10/00047 | 2/26/2010 | WO | 00 | 8/15/2011 |
