RU2788094C1 - Method and device for industrial production of rapeseed oil and rapeseed protein concentrate from rapeseed - Google Patents

Abstract

FIELD: oil and fat industry.

SUBSTANCE: method for processing of rapeseed grains (4) includes following stages: cleaning of rapeseed grains (4) from husk, where grains (4) are carried through a gap between peeling rollers (5), and separation of husk from husk-depleted grain fraction (6) by sifting and/or aspiration, so that husk, remaining in husk-depleted grain fraction (6), is no more than 4 wt.% of husk-depleted grain fraction (6), and pressing of cold-pressed rapeseed oil (25) from husk-depleted grain fraction (6). Moreover, a moisture content in the husk-depleted grain fraction is from 4 to 7 wt.%, and a temperature of cake (9) formed during pressing is limited to 70°C, a residual oil content is reduced to 18-28 wt.% per the dry weight of cake, and part of cake (9) is returned, mixed with husk-depleted grain fraction (6) before pressing, and pressed again. Water vapor (30) under pressure is supplied to cake (9), and then, cake (9) is expanded to form grits, while water vapor is dosed so that cake (9) is temporarily heated to a temperature of above 100°C under the action of water vapor, and grits after expansion has a temperature from 80 to 95°C, and grits are extracted with an organic solvent, while the second residual oil content is reduced to 2 wt.% or lower per dry matter of grits. After expansion, part of cake (9) is returned to the process. Device (1) for implementation of the method for processing of rapeseed grains (4), according to one of the previous paragraphs, contains: peeling rollers (5) forming a gap for cleaning of grains (4) from husk; a separation device located after the gap between rollers, with at least one sieve or winnower for separation of husk-depleted grain fraction (6) from husk-enriched grain fraction (31); flattening rollers (7) for rolling of husk-depleted grain fraction (6) into flakes, screw press (8) for pressing of cold-pressed rapeseed oil (25) from husk-depleted grain fraction (6) rolled into flakes, containing a screw and a sieve casing, wherein screw press (8) produces cake (9); and return device (34) intended for return of part of cake to screw press (8). Expander (14) is installed behind screw press (8) for supply of water vapor (30) under pressure to cake (9) and for subsequent expansion of cake (9) to obtain grits, and extractor (15) is installed behind the expander, intended for extraction of grits with an organic solvent, and return device (34) is intended for return of part of cake (9) after expander (14).

EFFECT: invention allows for development of a stable, reproducible, and continuous method, as well as a device for its implementation, using which, along with high-quality cold-pressed rapeseed oil, protein-containing products can be obtained from rapeseed at low cost, which can be processed into high-quality feed and food products.

25 cl, 2 dwg, 1 ex

Description

The field of technology to which the invention belongs

The invention relates to a method for processing rapeseed grains with the following steps: cleaning the grains from the husk, while the grains are passed through the gap between the shelling rollers, separating the husk from the poor husk fraction of grains by sifting and / or winnowing, so that the husk remaining in the poor husk fraction of grains, was not more than 4 wt.% of the poor husk fraction of grains, and the extraction of cold-pressed rapeseed oil from the poor husk fraction of grains, and the moisture content in the poor husk fraction of grains is from 4 to 7 wt.%, and the temperature of the cake formed during the extraction is limited to 70 °C, and the residual oil content is reduced to 18-28 wt.% in terms of the dry weight of the cake, and while part of the cake is returned, mixed with the poor husk fraction of the grains before pressing and squeezed again.

Rapeseed ( Brassica napus ), including the so-called zero, double zero and plus zero rapeseed varieties, as well as Canola , is the most commercially important oilseed worldwide after soybeans and a valuable raw material for the food industry, animal feed, biodiesel, as well as for oleochemistry. Unlike soybeans, which are primarily a source of vegetable protein, rapeseed is grown primarily for oil production. Rapeseed oil is mainly processed into biodiesel and edible oils. When rapeseed oil is extracted from rapeseed, a residue remains, which in the case of simply pressing rapeseed oil is called rapeseed cake, and after a possible additional extraction, rapeseed meal. Even the rapeseed meal remaining after additional solvent extraction makes up about 60% of the starting material. Thus, it accumulates in large quantities. When used for fattening animals, rapeseed meal, unlike soybean meal, cannot be used as a complete feed. Toxins, inedible ingredients and a high content of husks are completely unsuitable for use as a complete feed, as well as for use in the food industry, although the rapeseed protein contained in it, in principle, has an amino acid composition suitable for use in human and animal diets. Accordingly, the market price for rapeseed meal is significantly lower than for soybean meal. At the same time, there is a high demand for proteins suitable for food purposes, in particular from non-genetically modified sources. Such proteins are in great demand, for example, in fish farming, aquaculture and poultry fattening.

In order for the rapeseed protein contained in the residues from rapeseed oil extraction to be usable in large quantities, at least as animal feed, the amount of toxins and other harmful by-products must be reduced or completely eliminated. In addition, it is desirable to raise the protein content to the level of soybean meal and soy protein concentrate derived from it.

State of the art

Extraction of oil from rapeseed is carried out on an industrial scale by mechanical and/or chemical methods. In mechanical extraction, oil is squeezed out of rapeseed grains by hot or cold pressing.

It is generally accepted that the so-called cold-pressed rapeseed oil is obtained if the temperature is kept below 50°C during the pressing. However, the Codex Alimentarius clearly defines cold-pressed oil in such a way that cold-pressing is carried out without heat input. According to the definition of the Codex Alimentarius, the residual oil content in the oil cake resulting from pressing rapeseed can be reduced to about 15 wt.% in terms of dry matter.

According to the provisions on edible fats and edible oils of the German Food Law, the Federal Ministry of Food Industry and Agriculture (BMEL), for cold-pressed oils, the content of trans fatty acids must not exceed 0.2%. A trans fatty acid content above 0.2% is indicative of thermal damage.

The residual oil content of the cake can also be further reduced by pressing at higher temperatures, but cold-pressed rapeseed oil will no longer be obtained.

If the rapeseed kernels are dehulled before pressing to obtain a hull-free cake, the residual oil content of the cake, in the case of cold pressing only, will be well above 15% by weight due to the lack of friction created by the husk. Therefore, the first cold pressing is often followed by a second hot pressing at a higher temperature in order to increase the oil yield.

The cake containing the husk is additionally extracted with hexane, while the residual oil content is reduced to less than 1 wt.%, and rapeseed meal remains, which is of limited value.

The cake left after pressing the cold-pressed oil is often not subjected to additional solvent extraction, as for small oil mills this would not be economically viable due to the necessary investment costs and safety requirements.

To make an oil after hot pressing or extraction with hexane suitable for use in food products, a refining process is necessary.

DE 40 41 994 A1 discloses a method and apparatus for husking rapeseed, according to which a combined pressure and impact treatment of rapeseed grains is carried out in order to reduce the husk content to less than 5%. In this known method, after cleaning the grains, the following steps are performed: classification of grains and separation of fine fractions, reduction of grain moisture by drying, pressure treatment by means of rollers with a gap between the rollers, the width of which is 0.2-0.4 of the average diameter of the seeds, shock separation broken husks from grains by means of pneumatic movement, winnowing, as well as screening and separation of husks from grains by means of electroseparation. For this purpose, in the specified known installation, a seed hopper, scales, a magnetic separator, a classification platform, a dryer, a roller shelling machine, a cyclone, a winnowing machine and an electric separator are sequentially placed. Dehusking the rapeseed can be followed by the extraction of rapeseed oil from the kernels.

Application DE 4041994 A1 is based on the fact that the grains reach the desired reduced moisture content for dehusking after storage for more than 3 months, or fresh rapeseed is heated to dry to a temperature of 95°C. Long-term storage requires large storage capacities with a corresponding investment in large silo-type warehouses, which is uneconomical and, moreover, does not guarantee that the rapeseed will have the same and uniformly distributed moisture in all parts, suitable for shelling. To maintain reproducible and continuous production, controlled and reproducible seed drying is essential. This is done at 95°C, i.e. at a temperature at which denaturation of rapeseed protein occurs (see e.g. Sofia Dahlberg's master's thesis, Lunds University, Sweden, 2017, "An investigation of rapeseed protein as a new food product").

For exfoliation to be effective, a subsequent shock separation of the broken husk is necessary. The impact separation puts additional pressure on the peeled beans, while due to the impact pressure, the oil comes out of the beans to their surface and makes it difficult to separate the husk. Thus, most of the crushed grains still remain attached to the husk. The separation of grains from loose husks is carried out with the help of cyclones, winnowers and electric separation, while the task of the winnower is to separate the unpeeled grains.

For the actual separation of the husk, electroseparation is used, which has not yet been used on an industrial scale for processing rapeseed, since the high voltage field required for this is associated with serious problems, and the separation of the husk becomes less effective at high productivity.

EP 1074605 A1 discloses a method and apparatus for producing edible oil from rapeseed. While rapeseed is separated by classification into fractions with different particle sizes. The cleaned and classified rapeseed is dried at a temperature below 40°C. Dried rapeseed is crushed. Crushed rapeseed is divided into three fractions of particles of different sizes, of which one fraction, called useful grinding, is divided into peeled rapeseed and husk. The peeled rapeseed is moistened and then processed into flakes. The peeled rapeseed is then cold-pressed in a press to extract cold-pressed rapeseed oil. The cake thus formed can, like other by-products of this known process, be used as animal feed. Alternatively, it is proposed to use the separated by-products, in particular the husk fraction, for power generation.

The disadvantages of this known method are that, on the one hand, the drying of rapeseed must be carried out at temperatures below 40°C, so a large drying plant is required, which takes up a lot of space, and on the other hand, when crushing dried rapeseed, three fractions are formed, which must be classified according to size. Thus, classification begins after additional cleaning of crushed rapeseed.

In addition, of the three fractions, only rapeseed husks from a useful fracture are used in the future. All other components of the rapeseed are discarded along with the husk from the useful grinding, which makes the process uneconomical since the bulk of the rapeseed is not used to extract the oil.

WO 2011/029611 A2 describes a method for treating rapeseed kernels, in which the kernels are dehulled and separated into a kernel fraction on the one hand and a hull fraction on the other hand, wherein the kernel fraction is subjected to one or more pressing steps. The process is carried out in such a way that the cake containing solids and oil remaining during the extraction of the oil is dispensed, directly or after an additional grinding step, as a main component, filler or additive in human food. When issued as the main component for a food product, the cake peeled from the husk can be crushed. The milled product can be defatted by extraction and then used as a base for protein concentration and/or isolation.

From WO 2011/161665 A1 a method is known for producing soy protein concentrate from white soy bean flakes. Soybean flakes are extracted with hexane in a continuous hexane extractor to remove oil. After partial stripping of the hexane, the flakes are transferred to a water-alcohol extractor to extract residual hexane, sugars, and other alcohol-soluble material.

From US 4158656 A a method is known for obtaining a decontaminated product based on a protein concentrate from defatted oilseeds, in particular rapeseed. At the same time, oilseed grains are dried to a moisture content of 6%, peeled, then additionally dried to a moisture content of 1-3% and then degreased with hexane. Thereafter, the dehulled and defatted oilseeds are extracted under non-oxidizing conditions with a hydroalcoholic solvent, preferably isopropanol with the addition of bisulfite, and the solid residue of the extraction is dried at temperatures below 60°C.

The disadvantage of this known method is that the plant cells of the dehusked grains are not destroyed by pressing, so that the oil can be extracted more easily and more completely. In addition, hexane extraction starts directly from the cleaned grains, which makes sufficient degreasing much more difficult and leads to an increase in the duration of the extraction. In addition, high-quality cold-pressed rapeseed oil is not obtained, and the addition of an antioxidant is required. Cold-pressed native oil should not contain such additives.

From EP 1228701 A1 a method is known for the production of natural organic substances, in particular oils, fats, waxes, dyes, vitamins and/or other lipophilic substances and their derivatives from natural substances using centrifugal force. To do this, the raw material is crushed, lipophilic substances are extracted from the crushed raw material using an extractant, and the pulp in the field of centrifugal forces is separated into an aqueous phase containing solid components and a liquid organic phase containing hydrophobic substances.

From WO 2010/096943 A2 a method for obtaining a protein preparation from rapeseed is known, which includes the removal of the husk from the rapeseed grains, mechanical degreasing, in which only part of the oil is separated and which is carried out at a temperature averaged over the duration of the pressing process, below 80°C, and extraction. During mechanical degreasing, which is carried out at a temperature averaged over the duration of the pressing process below 80°C, only part of the oil is separated. During extraction, protein flour is depleted of extraneous protein substances. Extraction is followed by processing of grains by size in order to obtain bulk material with a given particle size distribution. More specifically, this known method starts with dehusking rapeseed kernels by splitting in a hammer mill and separating into a high grain content coarse fraction and a high husk content fine fraction in an air stream in a labyrinth classifier. The grain fraction is then cold pressed in a screw press at temperatures of 30-45° C. to a residual oil content of about 23% by weight, whereby a cake is obtained in the form of strips pressed together, called pellets. Cake pellets are degreased with hexane in a Soxhlet apparatus to a residual oil content below 3%. The solvent is then removed in a stream of air at room temperature. The resulting extracted protein meal granules are treated without further grinding with an ethanol solution during the percolation process. The resulting finished protein concentrate is used with or without additional grinding.

Document WO 2010/096943 A2 assumes that rapeseed is already dried during storage at temperatures below 95° C., preferably below 40° C., the aim being to achieve enzyme inactivation and limited protein denaturation. However, temperatures below 40° C. cause neither enzyme inactivation nor protein denaturation. The rapeseed grains are then separated in a mill into a grain fraction and a husk fraction, with the husk separated by cracking rather than targeted crushing.

During mechanical degreasing, which is carried out at a temperature averaged over the duration of the entire pressing process, below 80°C, the temperature of the rapeseed oil exceeds the temperature limit of 40°C, which, according to the general opinion, must be observed in order to obtain quality cold-pressed rapeseed oil (http:/ /en.foodlexicon.org/r0000680.php).

In addition to direct use, the cake can be pressed into pellets after exiting the pressing screw. Soft oilseeds, such as hulled rapeseed, can only be pressed slowly and at low power due to the insufficient friction of the oil cake formed. If the exit of the screw press is partially covered by the array of granules, the internal pressure and resistance in the screw press increase so that the flattened oilseeds can hardly pass through the screw of the screw press. Because of this, part of the oilseeds passes along with the pressed oil through the sieve casing of the screw press and contaminates the oil.

As reported in WO 2010/096943 A2 itself, a color change occurs already when the cake is pressed into granules with a residual oil content of less than 17%, which indicates a significant denaturation of the protein. If the cake, according to WO 2010/096943 A2, has a residual oil content of only at least 10%, a very significant protein denaturation can be assumed.

In order to achieve the purity of the refined grains below 5% or 1% required in WO 2010/096943 A2, significant losses of grains during winnowing should be expected, since light grains and heaps of husks of equal weight are carried out together. Parts of the grains taken out with the husk are no longer available for the whole process and reduce the profitability of this known method. Industrial application of this known method has not yet been implemented.

DE 4035349 A1 discloses a method and plant for the production of oils from legumes and oilseeds, in which grains, for example, rapeseed, are processed to obtain lamellae, followed by moistening of these lamellae, followed by expansion at 105-125°C, followed by cooling. below 100°C and drying and pressing at temperatures <100°C until a residual oil content of 15-25% is reached. The cake formed during the pressing is extracted at a temperature of approximately 65°C.

This known method is based on the use of non-shelled legumes and oilseeds. They are subjected to expander processing at temperatures of 105-125°C without previous cold pressing. The oil is pressed only after the expanded material has cooled down to 65°C. Thus, the expander performs the function of breaking up the cells by cooking to facilitate the extraction of the oil.

The disadvantage is the impossibility of obtaining high-quality cold-pressed oil from seeds of legumes and oilseeds with a low content of husks. In addition, at the temperatures used, protein denaturation occurs, making further purification and recovery of proteins difficult.

DE 352 229 C1 discloses a method and apparatus for the thermal conditioning of oilseeds and oilseeds, in particular legume seeds, in order to obtain, on the one hand, oils and fats and, on the other hand, an oil- or fat-free meal suitable as animal feed. . At the same time, the cleaned, dried and crushed oilseeds and oilseed fruits after the previous processing on the plating rolls are heated for a short time at a pressure above atmospheric pressure in an atmosphere that does not contain air or oxygen, to temperatures above 105°C-148°C and then at the same time cooled to temperatures below 100°C abruptly release pressure. Due to this, the activity of urease in the meal is largely suppressed, and the proteins in general, as well as their water solubility, are largely preserved. The known thermal conditioning can be carried out after pressing and before extraction, at which the extraction temperature is set to 50-65°C. Specifically for rapeseed, it is proposed to first thermally condition the polished kernels under relatively mild conditions, and then press the warm material to obtain rapeseed oil, and the cake is thermally conditioned again under more severe conditions, cooled and, finally, extracted in a known manner. This should allow optimal extraction of the oil contained in the husks and achieve a clear separation of the pressed rapeseed oil from the kernels and the extracted oil from the husks.

In this known method, only oilseeds are used, not peeled. The cooking process preceding extraction is replaced by expansion. High-quality cold-pressed oil is not obtained in this case. The high temperatures of rapeseed lead to protein denaturation.

EP 2783576 A1 describes a process for obtaining rapeseed protein concentrate by processing rapeseed grains. The grains are cleaned from the husk to obtain a fraction of rapeseed grains. The fraction of rapeseed grains is partially degreased in a screw press. Between 5% and 60% of the resulting protein-containing cake is returned and mixed with the rapeseed fraction before the screw press to increase friction and pressure in the screw press. The remainder of the protein-containing cake is washed with a water-alcohol solution to at least partially remove sugar, tannins, sinapins and glucosinolates and to obtain a protein concentration of rapeseed cake with a residual oil content of 5-25% (w/w). The protein concentrate of rapeseed cake is dried at temperatures in the range of 60°C-120°C to achieve a moisture content below 10%. The rapeseed fraction can be preheated to 70°C.

EP 2783576 A1 does not disclose to what extent the cake is added, directly or crushed, to the rapeseed fraction and how much the pressing efficiency is increased as a result.

The proportion of husks in the extraction of oil from shelled rapeseed is about 15%. The husks, when squeezed in a screw press, create friction, which is necessary to create a high pressure and thus achieve a high pressing power. Since EP 2 783 576 A1 states that the proportion of husks in the rapeseed fraction is between 1% and 10%, it can be deduced from the amount of returned cake that increasing friction by returning cake is not very effective. Specifically, the most favorable recycle ratio is 1:0.25, with the cake being heated to 70°C before pressing. There are 250 kg of cake per 1 ton of rapeseed fraction, which corresponds to about 20% of cake in the pressed mass in addition to 1-10% of husk. In other words, 20% of the cake compensates for the loss of about 5-10% of the husk, which is formed during the cleaning of the grains.

The disadvantage is that there is a significant risk of microbes entering the screw press due to the cake coming back over and over again. The temperature of the cake remains so low that no pasteurization of the cake occurs. Contamination of the screw press leads to contamination of the cake with toxins and to the introduction of microbes and toxins into all products of the known method.

Even if the cake contamination is later removed by hydroalcoholic extraction, the risk of contamination with toxins remains. In order to avoid contamination with germs and toxins, the screw press must be cleaned and disinfected frequently, which means a stop in production. This limits the industrial applicability of the known method.

In addition, the protein content of rapeseed cake protein concentrate does not meet the definition of protein concentrate adopted for soy protein concentrate, which requires a protein content of more than 60% on a dry matter basis. Due to the lower protein content of rapeseed cake protein concentrate, we can only speak of rapeseed protein flour.

Purpose of the invention

The invention is based on the task of developing a stable, reproducible and continuous process, as well as a device for its implementation, with the help of which, in addition to high-quality cold-pressed rapeseed oil, protein-containing products can be obtained from rapeseed at low cost, which can be processed into high-quality feed and food, while allowing the method and apparatus to be applied on an industrial scale.

Decision

The purpose of the invention is achieved by a method with features of independent claim 1 and by means of a device with features of claim 20 of the claims. Preferred embodiments of the method according to the invention and the device according to the invention are defined in the dependent claims.

Description of the invention

In the method of processing rapeseed grains according to the invention, the grains are cleaned of husks, for this they are passed through the gap between the shelling rollers, the husk is separated from the poor husk fraction of grains by sifting and / or winnowing, so that the husk remaining in the poor husk fraction of grains is no more than 4 wt.% of the poor husk fraction of the grains. Cold-pressed rapeseed oil is pressed from the poor husk fraction of grains, while the moisture content in the poor husk fraction of grains is from 4 to 7 wt.%, and the temperature of the formed cake is limited to 70 ° C, and the first residual oil content is reduced to 18-28 wt.% based on the dry weight of the cake. Pressurized water vapor is supplied to the cake, and then the cake expands with the formation of grits, while the water vapor is dosed so that the cake under the action of steam temporarily heats up to a temperature above 100°C, and the grit after expansion has a temperature of 80°C to 95 °C. The grist is extracted with an organic solvent, while the second residual oil content is reduced to 2 wt.% dry weight or less. After expansion, part of the grains is returned, mixed with the poor husk fraction of grains before pressing, and pressed again.

In the method according to the invention, due to the return of part of the grits during the extraction, the friction of the lean husk fraction of the grains is increased, which at least significantly helps to limit the temperature of the resulting oilcake to 70 ° C, despite the reduction of the first residual oil content to 18-28 wt.% of the dry weight of the oilcake. It may also be necessary to return part of the cake so that, despite the reduction of the first residual oil content to 18-28 wt.% of the dry weight of the cake, it is generally possible to limit the temperature of the cake to 70°C.

In the method according to the invention, the rapeseed kernels are hulled before pressing the cold-pressed rapeseed oil. Accordingly, the cake formed during the extraction, as well as the semolina formed as a result of the expansion of the cake, contain little husk. Along with a slight increase in the quality of cold-pressed rapeseed oil, this leads, in particular, to a significant increase in the potential for the use of semolina. The groats can already be used as such as animal feed. It is hygienically safe due to the heating of the cake, but, nevertheless, due to the short period of this heating, it has a favorable amino acid composition with minimal unwanted denaturation.

In particular, the semolina has a cohesive but open structure, favorable for its further processing, which, as will be explained below, can be maintained throughout processing.

If necessary, the process according to the invention may begin by cleaning the rapeseed kernels to remove impurities such as stones or chaff. Refined grains can be classified by grain size to separate grains that are not well suited for subsequent exfoliation. In particular, grains smaller than the minimum size of 1.2-1.8 mm, preferably about 1.4 mm, and larger than the maximum size of 2.6-3.0 mm, preferably about 2.8 mm, can be separated. At the same time, grains larger than the maximum size can be cleaned separately using a device adapted to their size, and grains below the minimum size can be used for other purposes. Usually the proportion of fine grains is less than 8 wt.%, often less than 4 wt.%.

Before or later, the peeling grains are adjusted to a moisture content of 4 to 7 wt.%, preferably about 5 wt.%, and dried if necessary. The drying temperature should be chosen so as not to exceed the temperature of the grains of 70°C, preferably 65°C, to avoid protein denaturation during drying. To break the husk, the grains are passed through a gap between the shelling rollers, which is typically at least 20% narrower than the minimum grain size. The grains can also be passed successively through several flaking gaps with decreasing width.

The grains crushed between the shelling rollers are then separated by sifting and/or winnowing, which also includes suction of the husk, into a husk-poor grain fraction and a husk-rich grain fraction. In this case, the husk remaining in the poor husk fraction of grains is not more than 4 wt.%. Preferably its proportion does not exceed 3.5 wt.%.

By winnowing, it is possible to achieve a yield of a husk-poor grain fraction, typically greater than 75%, preferably about 80%. The husk-rich grain fraction is complementary to the husk-poor grain fraction, so that the yield of the husk-rich grain fraction is between 20% and 25% of the amount of rapeseed used.

In the husk-rich grain fraction, grains are still present, which can be up to 40% by weight of the husk-rich grain fraction. Therefore, it is advisable to additionally process the fraction of grains rich in husks. This can be done by conventional means, such as pressing the oil at temperatures above 90° C. or solvent extraction of the husk-rich grain fraction, in particular hexane. Alternatively, the husk-rich grain fraction can be mixed with water at about 20-30° C., i. e. at room temperature, or at about 25° C., to cause the fibers contained in the grains to swell, and thus the grains to float, to obtain an additional hull-poor grain fraction.

Due to the different morphology, swelling of the fibers contained in the husk does not occur, or at least occurs to a lesser extent. In addition, the grains differ from the husks in their higher oil content. After swelling of the fibers in the grains, the grains have a lower density than water, while the husk still has a higher density than water. Accordingly, flotation of grains occurs, and flotation and the accompanying separation of grains and husks can be facilitated by the introduction of fine gas bubbles and/or by gentle mixing with low shear. Floated grains are taken as an additional fraction of grains poor in husks. Moisture can be removed from them using a belt press and added to the fraction of grains previously separated by a poor husk. This addition can be carried out even before the extraction of cold-pressed rapeseed oil, but also later. Preferably, however, the introduction of an additional hull-poor grain fraction into the main material flow occurs before the introduction of pressurized steam and subsequent expansion to form grit. The separated husk fraction can be separated due to its higher density than water, further purified and then used, for example, thermally or in a biogas plant.

After peeling and before pressing, the fraction of grains poor in husk can be rolled into flakes, for this it is passed through at least one gap formed between the flattening rolls. The temperature of the flakes should be maintained below 45°C. The flakes preferably have a thickness of 0.1 to 0.8 mm.

The extraction of the poor husk fraction of the grains proceeds without the supply of additional heat. However, due to the work done during spinning, there is an increase in temperature. According to the invention, this increase is limited to a maximum temperature of 70° C. of the cake formed. As a result, the trans fatty acid content of cold-pressed rapeseed oil is reliably kept at 0.2%, and often much lower.

During pressing, it is possible to collect cold-pressed rapeseed oil from the first oil fraction, which during pressing was not heated above the first limit temperature, and from the second oil fraction, which during pressing was heated above the first limit temperature. In this case, the first oil fraction experienced the least thermal effect on the oil composition and is a high quality rapeseed oil obtained by the method according to the invention. According to the Codex Alimentarius, the second oil fraction is also high quality cold-pressed rapeseed oil. A third oil fraction can also be collected which, during the pressing, is heated above the second limit temperature. The first limiting temperature delimiting the first and second oil fractions may be from 35°C to 50°C. Preferably it is about 40°C. Thus, at a maximum cake temperature of 70°C, the first oil fraction has an average temperature of 32-36°C and contains markedly less than 0.1% trans fatty acids, while the second oil fraction has an average temperature of 40-50°C and contains at least significantly less than 0.2% trans fatty acids. The second limiting temperature delimiting the second and any third oil fraction may be about 60°C.

When pressing according to the invention at cake temperatures not exceeding 70° C., the husk-poor grain fraction can be pressed to a first residual oil content of 18-28 wt.% or 20-24 wt.%, i.e. pressed to about 22 wt.% its dry weight. The cold-pressed rapeseed oil can be processed in a conventional manner by filtration and/or sedimentation, resulting in native cold-pressed rapeseed oil having food quality.

Conventional screw presses for oil extraction are designed for high power, i.e. they should provide the highest possible throughput. Due to the flaking of the beans and the corresponding lack of hulls, there is a power drop in the screw press, which reduces the productivity of cold pressed oil with a low hull content compared to conventional cold pressing and leads to additional costs, since larger screw presses with higher power consumption are required. . In addition, the higher power input also results in higher heating of the material in the screw press.

In order to increase the oil extraction capacity at low husk content in the screw press and thus increase economic efficiency, in the method according to the invention, a portion of the cake is added to the hull-poor grain fraction before pressing to increase the pressing friction. This return in the method according to the invention does not entail the risk of contamination of the screw press with microbes, since the returned part of the cake is separated only after expansion, that is, after disinfection of the cake with the added water vapor. In other words, the part of the cake returned according to the invention is a part of the grits formed from the cake as a result of expansion, which, due to the heat treatment, does not contain microbes and is hygienically safe. Thanks to the addition of grains to increase friction during cold pressing, the power indicators of conventional cold pressed oil are achieved. In addition, the mechanical properties of the semolina are more conducive to increasing productivity during the extraction than the properties of the cake prior to expansion.

It has proven advantageous to cool the returned part of the cake or semolina, before adding it to the poor husk fraction of grains, to a temperature of 20-35°C, preferably to 25-30°C, i.e. approximately to ambient temperature, while the returned part becomes hard and slightly deformable.

The returned part of the cake or semolina has a maximum particle size of 4 to 6 mm, preferably 5 mm. This may be, in particular, a fine fraction and fragments of grains. Depending on the proportion of hulls, the returned part of the cake or semolina replaces the previously separated husk, so the returned part can be up to 20% of the cake, respectively grits and, therefore, also the pressed mass. Depending on the type of press, reasonable values for the returned part are more than 5% and often from 10% to 15% of cake or semolina.

To return and increase friction when squeezing the poor husk fraction of grains, not only semolina, which is formed directly as a result of the expansion of the cake, is suitable. Also suitable is the semolina that remains after extraction with an organic solvent to reduce the residual oil content in it, this semolina can be sifted to a maximum size of 5 mm, dried and returned for pressing.

Surprisingly, grits increase friction and thus improve cold oil pressing efficiency without compromising the quality of the pressed oil. On the contrary, productivity and pressing power increase with the same power consumption, thus also limiting the temperature of the cake, since less mechanical power is converted into heat.

The cake obtained from pressing can be ground or used directly, and it can be supplemented with additional husk-poor grain fraction obtained during flotation or what is left of it after pressing.

Cake for supplying water vapor and subsequent expansion is carried out on the expander/extruder. By introducing pressurized water vapor, the material is compressed and in doing so is briefly heated to temperatures above 100° C., typically up to 140° C., before it expands and thereby cools again as a result of the expansion of the water vapor. The amount of steam should be set so that the temperature of the grits after expansion is 80-95°C.

The resulting expandate is the so-called semolina, which, unlike granules, in the form of which cake can accumulate after pressing, has an open-pore structure, which facilitates its further processing. A short-term temperature increase above 100°C and up to 140°C, caused by steam and pressure, inhibits enzymes and salmonella and makes the disinfected pore structure stable and elastic, which makes it possible to return the semolina to replace the husk during cold pressing. In addition, a short-term increase in temperature leads to partial denaturation of the proteins contained in the grains. This partial denaturation does not lead to a significant reduction in the nutritional or nutritional value of the proteins. Typically, the decrease in the solubility of the protein in the semolina, obtained in accordance with the invention, is no more than 20% compared to oilcake. However, partial denaturation of the protein causes the proteins to remain in the grits during subsequent extraction of the grits to extract additional oil and undesirable ingredients and are not lost. It is considered that the amount of water vapor and the resulting temperatures are set correctly if the protein denaturation in the grits is low compared to the oilcake, and the protein solubility, measured by NSI (Nitrogen Solubility Index, nitrogen solubility index) or PDI (Protein Dispersibility Index, protein dispersibility index) ) does not fall below 80% protein solubility in the cake.

The grit is extracted with an organic solvent to reduce its oil content to a second residual content of less than 2% by weight or 0.3 to 1.3% by weight based on the dry weight of the grit. As an organic solvent, in addition to hexane, you can also use any other organic solvent in which the oil dissolves well, such as isopropanol. It is also possible to use azeotropic or pure alcohol in the form of ethanol. This may in particular be a bio-alcohol, so that the processing of bio-rapeseed seeds results in a bio-rapeseed protein product.

For extraction, as for all the steps of the process according to the invention described above, standard industrial techniques can be used, in particular rotary extractors or belt extractors. The solvent used in the percolation process surrounds the particles of the grit, while the solvent forms a miscella, in which the oil contained in the grit is dissolved. This miscella is separated from the solvent by distillation in a known manner, so that an oil remains. We are talking about extracted rapeseed oil.

The extracted semolina can be dried and milled to form a high protein rapeseed protein meal with a protein content of more than 45 wt%, preferably more than 48 wt% on a dry matter basis, which, like high protein soy flour, is almost free of hulls. This rapeseed meal can be further processed by known methods.

One possible treatment for grits dried after extraction with an organic solvent is hydroalcoholic extraction to remove non-protein ingredients and fortify with proteins to obtain a rapeseed protein concentrate.

To do this, the grits are first sieved to separate fine fractions and fragments of grits, which are inevitably formed due to mechanical stress during drying. If these small particles are used to improve friction during cold pressing, a sieve is selected that retains particles from 5 mm in size, and if the material is additionally processed by alcohol extraction, a size limit of 1 mm is sufficient.

Then the grains, from which the fine fraction has been removed, are subjected to swelling in a water-alcohol mixture, for which 15 minutes are enough. The swelling must be non-destructive before the water-alcohol-saturated semolina is sent to a new extraction on a belt extractor, which can be carried out in a similar way to an extraction with an organic solvent. A suitable simple implementation is to use a swelling screw prior to extraction on a belt extractor in order to carry out the swelling in a continuous manner. However, any other technical means providing continuous swelling is also suitable.

Swelling can be carried out on an alcohol miscella obtained by extraction with alcohol in a belt extractor, which would correspond to a distillation process. Thus, the swelling screw leads to the next extraction stage.

Alternatively, the grits extracted with an organic solvent can be processed further directly, ie without drying and/or grinding.

Thus, in order not to destroy the structure of the grits and thus not create fine fractions, the grit can be dried by simple draining and dripping of the organic solvent before being discharged from the solvent extraction device. Typically, more than 50% of the solvent can be removed from the grits in this way. At the outlet of the solvent extraction device, the grains are non-destructively captured by a transport device and removed, for example, on a screw or belt conveyor. The conveying device delivers without shear forces the grains moistened with solvent to the filter, which is divided into separation zones. The material is transferred to the filter without damage. The filter may be a closed drum filter or a belt filter, in particular a vacuum belt filter. Between the transport device and the filter, a drum sluice can be built in to limit the reach of the solvent. After the solvent-wetted grits are placed on the filter, the filter is moved to the first position, in which the solvent content of the solvent-wetted grits is further reduced. This can be accelerated by applying vacuum to the vacuum belt filter. As a result, solvent fractions below 40% by weight can be achieved. In this case, the solvent is concentrated in the direction of the filter due to the capillary effect, so that a layer with a low solvent content is formed above the solvent in the capillaries of the grains, which wets only the surface of the capillaries. If hexane is used as an organic solvent, pure alcohol or an azeotropic solution of water and alcohol can be introduced to displace hexane starting from the second filter position. As a result of the separation of the solvent in the grain, an almost even alcohol/hexane boundary layer is obtained, so that only a small mixed hexane/alcohol/water fraction is formed. After two or three stages of washing, hexane in the grain structure is completely replaced by alcohol. This results in only small volumes of a mixed hexane/alcohol fraction, which can be treated separately by distillation. This example is provided for illustration purposes only. You can use any other technical device that allows the replacement of the solvent.

After changing the solvent, the grits can be extracted with a water-alcohol solution to obtain a purified rapeseed protein concentrate. When this water-alcohol solution may contain from 70% to 96% vol. alcohol. An alcohol concentration of 80-90% by volume is preferred. Extraction with alcohol, in particular ethanol, serves to remove toxins and other inedible ingredients. At a preferred alcohol concentration, the swelling of the fibers contained in the rapeseed material and the volume increase associated with it remains small. It also prevents a sharp drop in the percolation rate of the grits as a result of swelling. Too much swelling would block the grain capillaries.

The grains are preferably extracted with a water-alcohol solution in countercurrent. It is advisable to have a ratio of solids to solvent from 1 to 2 to 1 to 6. It is preferable to carry out at least 10 extraction steps in countercurrent. By the end of the extraction, a displacement wash can be carried out with an azeotropic, i.e. 96% alcohol to facilitate drying of the extracted material. The extracts are collected from the extraction stages. After the alcohol is distilled off, rapeseed molasses remains.

An azeotropic solution of water and alcohol can be collected separately and used to replace hexane with alcohol in the solvent exchange zone. This is advantageous in that the recovery of the water-alcohol mixture from the water-alcohol extraction does not require distillation and thus the plant can remain compact. A small volume remains for distillation from the solvent exchange step, in order to separate the hexane-alcohol-water mixture.

Alcohol extraction can also be carried out with the preparation of a suspension by grinding in a water-alcohol solution. The suspension is then purified by countercurrent centrifugation. This can be implemented as a standalone water-alcohol extraction or as a continuation of an existing extraction in a belt extractor. Vacuum belt extractors are also suitable for alcohol washing of suspensions.

Washing the slurry is particularly well suited for post-treatment after the intended extraction in a belt extractor, since many impurities are immobilized in the grit and are released only when the grit is opened. Thus, suspension washing performs the task of fine cleaning in order to improve the quality of the protein concentrate and protein fraction.

Purified rapeseed protein concentrate can be dried by roasting, flash drying or vacuum drying. The dried rapeseed protein concentrate has a protein content of over 60% by weight on a dry matter basis.

In the device according to the invention for carrying out the method according to the invention for processing rapeseed grains, containing shelling rollers with a gap between the rollers for cleaning the grains from the husk, a separation device with at least one sieve or fan is placed after the gap between the rollers to separate the poor husk fraction of the grains from the rich flakes, a screw press for squeezing cold-pressed rapeseed oil from flakes, and the screw press gives out the cake, and the return device, which is designed to return part of the cake to the screw press, is located behind the screw press an expander for supplying water vapor under pressure to the cake and subsequent expansion of the cake to obtain grits, and behind the expander there is an extractor designed to extract the grits with an organic solvent, and a return device designed to return part of the cake after the expander dera, i.e. in the form of a grain.

In particular, the return device may be capable of separating the returned part of the cake by sifting from the semolina a fraction of particles with a maximum size in the range of 4-6 mm. This screening can be carried out before and/or after extraction with an organic solvent in an extractor.

The return device may include a cooling system for cooling a portion of the cake. The cooling system may include, for example, a cooling air blower that cools a portion of the cake by lowering the temperature while evaporating the moisture content.

The screw press may include a screw rotating around a horizontal axis of rotation and a sieve casing, wherein the oil collecting tank located under the sieve casing has a shutter passing across the axis of rotation, which in the oil collecting tank separates from each other the oil fraction squeezed out first and squeezed out later the second the oil fraction of cold-pressed rapeseed oil, wherein the shutter can be displaced in the direction of the axis of rotation. By moving the shutter, the aforementioned first limit temperature delimiting the first and second oil fractions can be controlled. If a drive is provided that displaces the shutter in the direction of the axis of rotation depending on the signal of at least one oil temperature sensor mounted on the shutter, the first limit temperature can be set to a predetermined value even if the temperature distribution over the screw press changes. The sieve casing of the screw press can be made of perforated rods.

Further, the apparatus according to the invention may comprise a flotation tank for separating the husk-rich grain fraction by flotation in water into an additional husk-poor grain fraction and a husk fraction. In this case, the flotation tank can optionally have a compressed air connection at or near the bottom and/or contain an agitator.

An extractor placed behind the expander can also be designed to dry the grit or subject the still wetted grit to a solvent change and then extract the grit with an aqueous/alcoholic solution.

Preferred improvements to the invention are apparent from the claims, description and drawings. The advantages of features and combinations of several features mentioned in the description are only illustrative and may, alternatively or cumulatively, produce the desired result, without the need to achieve advantages only through embodiments of the invention. Without altering the subject matter of the appended claims, with respect to the scope of the disclosure of the original documents of the application and the patent, the following applies: additional features are revealed from the drawings, in particular, this concerns the presented geometry and the relative dimensions of several parts relative to each other, as well as their relative location and functional connection. It is also possible, and is hereby proposed, a combination of features of different embodiments of the invention or features of different claims, in deviating from the chosen relationship of claims. This also applies to such features that are presented in separate drawings or indicated in the description of the drawings. These features may also be combined with features of other claims. Likewise, the features listed in the claims may be omitted in other embodiments of the invention.

The features indicated in the claims and description should be understood in terms of their number, so that there is exactly this number or a number greater than indicated, without the need for explicit use of the expression "at least". Thus, for example, when referring to a screw press, it should be understood that there is exactly one screw press, two screw presses, or more than two screw presses. These features may be complemented by other features or be the only features that the product in question provides.

The position numbers used in the claims do not limit the scope of the objects protected by the claims. They serve only to facilitate the understanding of the claims.

Brief description of the figures

The invention is further explained and described in more detail with reference to the preferred embodiments shown in the figures.

In FIG. 1 shows a block diagram of the device according to the invention and the sequence of the method according to the invention.

In FIG. 2 shows a preferred embodiment of a screw press in an apparatus according to the invention.

Description of figures

In FIG. 1 shows a block diagram of a device 1 according to the invention and at the same time the sequence of the method according to the invention. Rape seed from the hopper 2 is subjected to classification and cleaning in the screening machine 3. After the screening machine 3, refined grains 4 with a given size range are obtained. After possible drying, in order to set the moisture content of the grains 4 to about 5% by weight, the grains 4 are dehusked by means of peeling rollers 5 having a gap between the rollers, behind which is a separating device. As a result, a husk-poor grain fraction 6 and a husk-rich grain fraction 31 are obtained. Cold-pressed rapeseed oil 25 is squeezed out of the flakes in the screw press 8. The resulting cake 9 is fed into the expander 14.

On the other hand, the husk-rich grain fraction 31 is mixed with water to form a slurry 32 in which the fibers contained in the grain portion of the husk-rich grain fraction 31 are swollen. A flotation 33 then takes place, in which an additional husk-poor grain fraction 10 floats and is thus separated from the husk fraction 11. The husk fraction 11 can be dried and/or milled and can be used, for example, in an incinerator or biogas plant. An additional fraction of grains 10 poor in husk is squeezed out in a belt press 12. Its solid part is added to the cake 9 before the expander 14. The water squeezed out by the belt press 12 is processed in an oil clarifier 13, in which the oil 26 is separated. Purified water undergoes UV disinfection treatment and is reused. The cake 9 and the additional hull-poor grain fraction 10 are ground and sent to the expander 14. In the expander 14, the temperature of the cake 9 rises briefly above 100° C., typically up to 140° C., as a result of the supply of pressurized water vapor. When leaving the expander, the water vapor expands and cools the material coming out in the form of grains 46 to 80-95°C. Grits 46 in the extractor 15 are first subjected to a solvent extraction step 16, for example hexane. After the solvent change step 17, a water-alcohol extraction 18 is carried out. Instead of the solvent change, drying 19 of the grits extracted with the solvent can be carried out. This may be followed by granulation 20 or further expansion of the dried material, or the rapeseed protein meal obtained after drying 19 is dispensed as a product.

Alcohol extraction 18 can also be carried out on grits obtained after drying 19 or on rapeseed protein flour. In the distillation step 21, the extracted rapeseed oil 27 is obtained from the miscella in the solvent extraction step 16. In the distillation 22, the solvent used in the solvent replacement step 17 is recovered. After distillation 23 of the alcohol extraction product 18, molasses 28 is obtained. Drying 24 of the alcohol extraction residue 18 yields a purified rapeseed protein concentrate 29.

The return device 34 returns part of the cake 9 after expansion from the outlet of the expander 14 to the screw press 8. In particular, a fine fraction is screened out from the grits 46 leaving the expander 14, in the cooling system 35 of the return device 34 the cake is cooled to a temperature of <35 ° C and is then added to the hull-poor grain fraction 6 to increase friction in the screw press 8. heating of the cake 9 formed in the screw press 8, as well as the residual oil content in the cake 9. This friction is provided by the cooled grits, without creating hygiene problems due to the return of part of the cake 9 to the screw press 8, since the grit 46 as a result of expansion in the expander 14 are being disinfected. In addition, the grist 46 has better mechanical properties in terms of increasing friction in the screw press 8 than the cake 9 to the expander 14.

Shown in FIG. 2, an embodiment of the screw press 8 in the device 1 according to the invention has an electric drive 36 which rotates the screw 37 of the press about a horizontal axis of rotation 38 relative to the sieve casing 39 in order to squeeze the rapeseed oil 25 from the poor husk fraction 6, thereby forming a cake 9. First, in in the direction of the rotation axis 38, the first oil fraction 42 is squeezed out, in which the rapeseed oil 25 does not exceed the temperature limit. The second oil fraction 43 is then pressed out, which is still cold-pressed rapeseed oil 25, since no heat is supplied to the screw press 8. However, under the action of the press screw 37 on the poor husk fraction of grains 6, the temperature rises in the screw press 8 along the rotation axis 38. It is limited by the maximum temperature of the cake 9, equal to 70°C. As a result, the second oil fraction 43 also has a trans fatty acid content of less than 0.2%. The content of trans fatty acids in the first oil fraction 42 is less than 0.1%. These two oil fractions 42 and 43 are separated in the oil-receiving bath 40 located under the sieve casing 39 by means of a shutter 41 passing across the axis of rotation 38. The shutter 41 is displaced by the drive 44, shown here by a double-headed arrow, along the axis of rotation 38, depending on the sensor located on the shutter 41 45 oil temperature so that the oil temperature sensor 45 does not register a temperature higher than the limit temperature of the first oil fraction 42.

Example

10 tons of rapeseed are cleaned, for example, rapeseed varieties "two zeros". Depending on the degree of contamination, from 2% to 3% of the original mass is removed. In the subsequent classification, up to 4% of grains with a size of less than 1.6 mm and more than 2.8 mm are removed. 94% of the original rapeseed with a moisture content of 7-9% is supplied for drying.

Rapeseed is dried at 60-70°C to a moisture content of 5 wt.% and, after cooling to 30°C, is sent to peeling rollers 5. Separation into a husk-rich grain fraction 31 and a husk-poor grain fraction 6 gives a yield of approximately 80 wt.% poor husk grain fraction and 20 wt.% husk-rich grain fraction 31. At the same time, the husk-rich grain fraction 31 contains 30-40 wt.% grain material, and the husk-poor grain fraction 6 contains less than 4% husk. The husk-rich grain fraction 31 contains a total of about 20 wt. % oil and 16 wt. % protein. The husk-rich fraction of grains 31 is mixed with water at 20-30°C. This results in a weight ratio of 1 to 6, i.e. for 1 kg of the hull-rich grain fraction 31 there is at least 6 kg of water. After the addition of water, the resulting slurry 32 is set in motion by gentle agitation without shear and stirred. The grain fibers swell for 15 minutes in the husk-rich grain fraction 31. During subsequent flotation 33, the mixed husk-rich grain fraction separates into a floating additional husk-poor grain fraction 10 and a husk fraction 11. To enhance flotation, air can be blown in the form of small bubbles. The swollen grains of the additional poor husk fraction of grains 10 are collected using a belt press 12. Water is separated and fed into the circuit of the fresh, rich in husk fraction of grains 31. From the additional poor husk fraction of grains 10 collected on the belt press 12, water is removed and added to the cake 9 before the expander 14 .

Then, the hull-poor grain fraction 6 is rolled into flakes with flattening rolls 7. The husk-poor grain fraction 6 is rolled out just enough to keep the temperature of the flakes below 45°C. To maintain this temperature, the conditioning rolls 7 can be cooled down. The flakes are fed directly to the screw press 8. In the screw press 8, the flakes are compressed by the screw 37 of the screw press 8. The cold-pressed rapeseed oil 25 that flows out is collected separately according to the temperature ranges. The first oil fraction 42 with a temperature of 35-40°C is a native rapeseed oil of the first cold pressing and has a content of trans fatty acids below 0.1%. The second oil fraction 43 with a temperature of 45-60°C is a native cold-pressed rapeseed oil 25 and has a trans fatty acid content of less than 0.2%. These two oil fractions give a total of about 2.8 tons of cold-pressed 25 rapeseed oil, of which 40% is virgin rapeseed oil and 60% is cold-pressed native rapeseed oil. The cake 9 exiting the screw press 8 has a residual oil content of 22-23% by weight.

The cake 9 is crushed, an additional fraction of grains 10 from the belt press 12, which is poor in husk, is added to it and sent to the expander 14. In the expander 14, when steam 30 is supplied under pressure, the cake heats up so much that the grain 46 as an expandate after leaving the expander 14 has a temperature 80-95°C. Grit 46 is cooled. The fine fraction and fragments with a particle size of up to 5 mm are sieved from the grains 46. The proportion of the fine fraction is from 3 to 6 wt.%. From 5 to 20 wt.% semolina is added to the poor husk fraction of grains 6 before the screw press 8 in the form of fines and chips to increase friction during cold pressing of rapeseed oil 25.

Grain particles 46 larger than 5 mm are extracted in several stages with hexane at 60°C in countercurrent mode in the carousel extractor of the extraction apparatus 15 under percolation conditions. The resulting miscella is distilled and hexane is fed back into the process. The duration of the extraction is 1 to 3 hours, preferably about 2 hours. The result is 1.1 tons of extracted rapeseed oil 27.

After extraction 16, the hexane-moistened grit 46 is left to drain and dry. The grit 46 is then fed either to a dryer 19 to produce high protein rapeseed protein meal or to a solvent change step 17 .

If drying 19 of the hexane-moistened grits 46 is chosen, then the dried grits 46 can either be milled to obtain a protein meal, or first sifted through a 1 mm sieve to reduce the proportion of fine particles. The grains 46 freed from small particles are then fed to the screw for swelling. The screw transports the grains 46 and transfers them to the belt extractor 18 for extraction with a water-alcohol solution containing 80% alcohol.

The solvent change step 17 is carried out in particular by means of a vacuum belt filter. After further transport, the contained hexane is covered with 96% ethanol. Subsequently, ethanol is absorbed by the grains, while ethanol is fed in countercurrent. After 3 cycles the hexane has been replaced by ethanol and the grit is now coated with 80% ethanol and swollen for 15 minutes in countercurrent. For swelling, you can use the alcohol solution coming out of the subsequent alcohol extraction 18 (molasses 28). The swollen material is unloaded, loosened and fed to a belt conveyor for subsequent alcohol extraction 18, on which the grains are additionally extracted with 80% ethanol, while the extraction time is from 1 to 3 hours. The last alcohol step may be to replace the water-alcohol mixture with 96% ethanol to reduce energy costs in the subsequent drying 24. This azeotropic alcohol can be used to displace hexane in the solvent change step 17. This is advantageous in that only a small amount of solvent needs to be rectified in the distillation step 22 .

The alcohol from the alcohol extraction 18 is distilled off and reused. Molasses 28 remains. The dry matter of molasses 28 corresponds to approximately 10-12% of processed rapeseed. Rapeseed protein concentrate 29 purified by alcohol extraction is dried and 3 tons are obtained.

The 29 rapeseed protein concentrate has the following composition:

protein content in dry matter (N*6.25) 64.0%±2%, dry matter 90%±2% oil content 0.4%±0.2% glycosinolate content ≤ 1 µmol/g polyphenols ≤ 0.1% sinapine ≤ 0.1% phytic acid 3%±2% Colour light coloured taste neutral concentrate yield per sorted rapeseed thirty%

The approximate composition of amino acids is close to the composition of rapeseed:

Typical amino acids per sample
g/100 g s.v. for protein
g/100 g protein aspartic acid asp 4.94 8.13 NE glutamic acid Glu 11.16 18.36 NE hydroxyproline Hyp 0.17 0.28 NE serine Ser 2.79 4.59 NE glycine gly 3.55 5.84 NE histidine His 1.86 3.06 E arginine Arg 4.45 7.33 (NE) threonine The 2.99 4.92 E alanine Ala 2.80 4.60 NE proline Pro 3.68 6.06 NE tyrosine Tyr 1.60 2.63 (NE) valine Val 3.58 5.89 E BCAAs methionine Met 1.18 1.94 E BCAAs isoleucine ile 2.73 4.49 E leucine Leu 4.73 7.78 E BCAAs phenylalanine Phe 2.72 4.47 E lysine Lys 4.05 6.66 E cysteine/cyst Cys 1.68 2.76 (NE) tryptophan trp 1.03 1.69 E NE=Essential E=Essential BCAA=branched amino acid Essential amino acids on AK standard 24.87 40.90 40% for toddlers/middle age 35.26 58.00 57% BCAA 9.49 15.61 15.4%

A typical oil analysis shows a composition close to that of rapeseed:

Oil analysis saturated fatty acids 6.3% monounsaturated fatty acids 66.0% polyunsaturated fatty acids 27.6% trans fatty acids 0.06% omega-3 acids 9.2% omega 6 acids 18.4% water 0.05% phosphorus <2.0 mg/kg sulfur 3.0 mg/kg

List of positions

1 device 2 bunker 3 screening machine four grain five shelling rollers 6 poor husk fraction of grains 7 flaking rollers 8 screw press nine cake 10 additional fraction of grains poor in husk eleven husk fraction 12 belt press 13 oil clarifier fourteen expander 15 extractor sixteen solvent extraction 17 solvent replacement eighteen alcohol extraction nineteen drying 20 granulation 21 distillation 22 distillation 23 distillation 24 drying 25 cold pressed rapeseed oil 26 butter 27 extracted rapeseed oil 28 molasses 29 purified rapeseed protein concentrate thirty water vapor 31 husk-rich grain fraction 32 suspension 33 flotation 34 return device 35 cooling 36 drive unit 37 auger press 38 axis of rotation 39 sieve casing 40 oil collecting tank 41 gate 42 first oil fraction 43 second oil fraction 44 drive unit 45 oil temperature sensor 46 krupka

Claims (46)

1. A method for processing grains (4) of rapeseed, including the following steps: - cleaning the grains (4) of rapeseed from the husk, where the grains (4) are passed through the gap between the shelling rollers (5), and the separation of the husk from the poor husk fraction of the grains (6) by sieving and / or winnowing, so that the husk remaining in the poor husk fraction of grains (6), was not more than 4 wt.% of the poor husk fraction of grains (6), and - extraction of cold-pressed rapeseed oil (25) from the poor husk fraction of grains (6), - moreover, the moisture content in the poor husk fraction of grains is from 4 to 7 wt.%, - moreover, the temperature of the cake (9) formed during the extraction is limited to 70 ° C, - moreover, the residual oil content is reduced to 18-28 wt.% based on the dry weight of the cake, and - moreover, part of the cake (9) is returned, mixed with the poor husk fraction of grains (6) before pressing and again pressed, characterized in that - cake (9) is supplied with water vapor (30) under pressure and then the cake (9) is expanded with the formation of grains, while the water vapor is dosed so that the cake (9) under the action of water vapor is temporarily heated to a temperature above 100 ° C, and the grits after expansion had a temperature of 80 to 95°C, the grits are extracted with an organic solvent, the second residual oil content being reduced to 2% by weight or less, based on the dry matter of the grits, and - after expansion, part of the cake (9) is returned to the process. 2. Method according to claim 1, characterized in that the portion of the cake (9) returned after expansion is separated from the grit before extraction and/or after extraction. 3. The method according to p. 2, characterized in that the part of the cake (9) returned after expansion is separated from the grits before extraction and/or after extraction by sifting out smaller particles and, optionally, by sifting out a fraction of particles with a maximum size of 4- 6 mm. 4. The method according to one of the preceding claims, characterized in that the part of the cake (9) returned after expansion is cooled to a temperature in the range of 20-35°C or 25-30°C before a new pressing. 5. Method according to one of the preceding claims, characterized in that the part of the cake (9) returned after expansion is from 5 to 20% by weight of the cake (9). 6. Method according to one of the preceding claims, characterized in that the hull-poor grain fraction (6) is squeezed out without heat supply or with heat removal. 7. Method according to one of the preceding claims, characterized in that the husk-rich grain fraction (31) is separated by flotation (33) in water into an additional husk-poor grain fraction (10) and a husk fraction (11), wherein the additional husk-poor grain fraction (10) is optionally added to the lean husk fraction of the grains (6) before the pressurized steam (30) is introduced. 8. The method according to one of the previous paragraphs, characterized in that the poor husk fraction of grains (6) with a moisture content of 5-8 wt.% of its dry weight is rolled into flakes before pressing, and flakes, optionally - rolled out to a flake thickness of 0.1-0.8 mm and - maintained at a temperature of flakes not higher than 45°C. 9. The method according to one of the preceding claims, characterized in that the cold-pressed rapeseed oil (25) is collected from a first oil fraction, which, during the extraction, was heated to a temperature not exceeding the limit temperature, and a second oil fraction, which, during the extraction, was heated above the limit temperature. temperature, and the limiting temperature is from 40°C to 50°C. 10. The method according to claim 9, characterized in that the husk-poor fraction is squeezed out by means of a screw press (8) with a screw (37) of the press rotating around a horizontal axis of rotation (38) and a sieve casing (39) surrounding the screw (37) press, and in the oil collecting tank (40) located under the sieve casing (39), the shutter (41), passing across the axis of rotation (38), is continuously displaced in the direction of the axis of rotation (38) so as to separate the first oil fraction (42) from each other ) and a second oil fraction (43) of cold-pressed rapeseed oil (25) in the oil collection tank (40). 11. Method according to claim 10, characterized in that the shutter is displaced in the direction of the axis of rotation (38) depending on the signal from at least one oil temperature sensor (45) mounted on the shutter. 12. Method according to one of the preceding claims, characterized in that the cake (9) is crushed under pressure before steam (30) is supplied. 13. A method according to one of the preceding claims, characterized in that the grit is extracted with an organic solvent in order to reduce the second residual oil content to 0.3-1.3 wt.% of the dry weight of the grit. 14. Method according to one of the preceding claims, characterized in that the organic solvent with which the grit is extracted to reduce the second residual oil content to 2 wt.% of the dry weight of the grit or less is hexane or at least 95% alcohol . 15. The method according to one of the preceding claims, characterized in that the solvent-impregnated grit is dried while maintaining its porous structure or subjected to a solvent exchange, using at least one replacement solvent selected from pure alcohol and an azeotrope solution of water and alcohol. 16. Method according to one of the preceding claims, characterized in that the organic solvent-extractable grit is extracted with a water-alcohol solution to obtain a purified rapeseed protein concentrate (29), the water-alcohol solution containing 70-96 vol.% or 80-90 vol. .% alcohol. 17. The method according to p. 16, characterized in that the grains are crushed with a water-alcohol solution to a suspension and extracted in countercurrent. 18. The method according to claim 16 or 17, characterized in that the water-alcohol solution is displaced with at least 95% ethanol. 19. The method according to one of paragraphs. 16-18, characterized in that the purified rapeseed protein concentrate (29) is dried by frying, flash drying or vacuum drying. 20. Device (1) for implementing a method for processing grains (4) of rapeseed according to one of the previous paragraphs, containing - peeling rollers (5), forming a gap for cleaning grains (4) from the husk; - a separating device, located after the gap between the rollers, with at least one sieve or winnower for separating the poor husk fraction of grains (6) from the rich husk fraction of grains (31); - flattening rollers (7) for rolling out the poor husk fraction of grains (6) into flakes, - a screw press (8) for squeezing cold-pressed rapeseed oil (25) from the flaked poor husk fraction of grains (6), containing a screw and a sieve casing, and the screw press (8) produces cake (9); and - a return device (34) designed to return part of the cake to the screw press (8), different in that - an expander (14) is installed behind the screw press (8) for supplying steam under pressure (30) to the cake (9) and for subsequent expansion of the cake (9) to obtain grits, and - an extractor (15) is installed behind the expander, designed for the extraction of grains with an organic solvent, and - the return device (34) is designed to return part of the cake (9) after the expander (14). 21. The device (1) according to claim 20, characterized in that the return device (34) is designed to separate the cake (9) from the grits before and / or after extraction with an organic solvent in the extractor (15) by screening out the particle fraction with the maximum particle size in the range of 4-6 mm. 22. Apparatus (1) according to claim 20 or 21, characterized in that the return apparatus (34) has a cooling system (35) for cooling a portion of the cake (9). 23. Device (1) according to one of paragraphs. 20-22, characterized in that the screw press (8) contains a screw (37) rotating around a horizontal axis of rotation (38), and a sieve casing (39), and in the oil collecting tank (40) located under the sieve casing (39) (41), passing across the axis of rotation (38) and separating in the oil collection tank (40) from each other the first oil fraction (42) squeezed out at the beginning and the second oil fraction (43) squeezed out later of the cold-pressed rapeseed oil (25), can be displaced in direction of the axis of rotation (38). 24. The device (1) according to claim 23, characterized in that a drive (44) is provided that moves the shutter (41) in the direction of the rotation axis (38) depending on the signal of at least one sensor installed on the shutter (41) ( 45) oil temperature. 25. Device (1) according to one of paragraphs. 20-24, characterized in that a flotation tank is provided, which is designed to separate the husk-rich grain fraction (31) by flotation (33) in water into an additional grain fraction (10), poor in husk, and a husk fraction (11), moreover, flotation the tank may optionally have a compressed air connection at or near the bottom and/or an agitator.

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