Method and apparatus for industrial extraction of rapeseed oil and rapeseed protein concentrate from rapeseed
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EURO PROTEIN GMBH
- Filing Date
- 2019-04-09
- Publication Date
- 2026-06-02
Smart Images
Figure CN114026209B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for processing rapeseed kernels, comprising the following steps: dehulling the kernels, wherein the kernels are guided through the gap between dehulling rollers, and the husks are separated from the kernels with few husks by sieving and / or air separation, such that the total amount of husks remaining in the kernels with few husks is no more than 4% by weight of the kernels with few husks, and cold-pressed rapeseed oil is extracted from the kernels with few husks, wherein the water content of the kernels with few husks is 4%-7% by weight, wherein the temperature of the cake in the resulting cake is limited to 70°C, wherein the remaining oil content is reduced to 18%-28% by weight of the dry mass of the cake, and wherein a portion of the cake is transported back, mixed with the kernels with few husks before pressing, and pressed again.
[0002] Rapeseed (Brassica napus), including so-called zero-, double-zero-, and plus-zero- varieties, is the world's most commercially important oilseed after soybean and a valuable raw material for the food industry, feed industry, biodiesel products, and oleochemicals. Unlike soybeans, which are primarily used as a source of plant protein, rapeseed is mainly grown for oil extraction. Rapeseed oil is primarily processed into biodiesel and edible oil. The residue left during rapeseed oil extraction is called rapeseed cake when pressed purely for oil and rapeseed meal after additional solvent extraction, if necessary. The rapeseed meal remaining after additional solvent extraction also constitutes approximately 60% of the original material. Therefore, it accumulates significantly. Unlike soybean meal, rapeseed meal cannot be used as complete animal feed when used as animal feed. Toxins, anti-nutritional components, and high hull content also hinder its application as a complete feed, such as in the food industry, even though the rapeseed protein it contains theoretically contains amino acids beneficial for human and animal nutrition. Correspondingly, the market price of rapeseed meal is significantly lower than that of soybean meal. Simultaneously, there is a high demand for protein suitable for nutritional purposes, particularly from non-GMO sources. This protein is particularly needed in fish farming, aquaculture, and poultry farming.
[0003] In order to enable the large-scale use of rapeseed protein, contained in the residues from rapeseed oil extraction, at least as animal feed, it is necessary to reduce or remove toxins and other interfering impurities. Furthermore, the protein content should preferably be increased to the level of soybean scrap and soybean protein concentrate derived from said soybean scrap. Background Technology
[0004] Oil extraction from rapeseed is achieved on a large scale using mechanical and / or chemical methods. In mechanical extraction, oil is extracted from rapeseed kernels by hot or cold pressing.
[0005] Generally speaking, when the temperature is maintained at 50°C during pressing, so-called cold-pressed rapeseed oil is produced. However, the Codex Alimentarius defines cold-pressed oil as oil that does not release heat during pressing. This Codex definition allows for the reduction of the residual oil content in the rapeseed cake produced during pressing to approximately 15% by weight of the dry mass of the cake.
[0006] According to the guidelines for edible fats and oils in the German Food Book published by the Federal Ministry of Food and Agriculture (BMEL), cold-pressed oils are required to contain no more than 0.2% trans fatty acids. A trans fatty acid value greater than 0.2% indicates heat damage.
[0007] By pressing at a higher temperature, where cold-pressed rapeseed oil is no longer produced, the residual oil content in the cake can be further reduced.
[0008] When rapeseed kernels are dehulled before pressing to obtain a cake with fewer husks, the residual oil content of the cake during cold pressing alone significantly exceeds 15% by weight due to the lack of friction through the husks. Therefore, a second hot pressing at a higher temperature is usually performed after the first cold pressing to increase oil yield.
[0009] The hulled cake is further extracted with hexane, wherein the remaining oil content is reduced to less than 1% by weight and rapeseed debris is retained, which has only limited value.
[0010] The cake remaining after cold pressing is usually not extracted with solvents because it is uneconomical for small oil mills due to the required investment costs and safety requirements.
[0011] To ensure that hot-pressed or hexane-extracted oils meet food safety standards, a refining process must follow immediately.
[0012] A method and assembly for dehulling rapeseed are disclosed in DE 40 41 994 A1, wherein the rapeseed kernels are subjected to extrusion and impact processing to reduce the hull content to less than 5%. In the known method, the steps immediately following kernel cleaning are: sorting and separating the kernels into smaller sizes; reducing the moisture content of the kernels by drying; extrusion processing by rollers with a roller gap of 0.2 to 0.4 times the average kernel diameter; impacting and loosening the broken hulls from the kernels by a pneumatic conveying device; and air-separating and picking the hulls from the kernels by an electric separator. For this purpose, in the known arrangement, a seed hopper, a scale, an iron separator, a sorting plate, a dryer, a roller dehulling device, a cyclone separator, an air separator, and an electric separator are connected in series. Following rapeseed dehulling, rapeseed oil can be extracted from the kernels.
[0013] DE 40 41 994 A1 relates to the reduction of moisture content in rapeseed kernels to the desired level for hulling by storing them for more than three months or by heating fresh rapeseed to 95°C for drying. Long storage times require high storage capacity, which necessitates corresponding investments in large storage silos, which is uneconomical, and does not guarantee that the rapeseed will uniformly and evenly possess suitable moisture content for hulling in all parts. For reproducible and widespread production, it is essential to inspect the seeds and reproducibly dry them. This is carried out at 95°C, at which point the rapeseed protein denatures, see, for example, Master Thesis Sofia Dahlberg, Lunds Universitet Sweden, 2017, “An investigation of rapeseed protein as a new food product.”
[0014] To ensure efficient hulling, the broken shells are then loosened by impact. This impact loosening applies additional pressure to the hulled kernels, causing oil to be drawn from their surface during impact and making shell separation difficult. As a result, most of the crushed kernels remain attached to the shells. Separation of the kernels from the loosened shells is achieved through a cyclone separator, an air classifier, and an electric separator, where the air classifier separates the unhulled kernels.
[0015] Electric separators are used to truly separate the shells, but they have not been used in large-scale rapeseed processing to date because of obvious problems related to the required high-voltage electric field and the loss of efficiency in shell separation at high production volumes.
[0016] A method and apparatus for producing edible oil from rapeseed are disclosed in EP 1 074 605 A1. In this method, rapeseed is sorted into components of different particle sizes. The purified and sorted rapeseed is dried at 40°C. The dried rapeseed is crushed. The crushed rapeseed is separated into three components of different particle sizes, wherein the component referred to as usable fragments is broken down into dehulled rapeseed and husks. The dehulled rapeseed is moistened and then pressed into flakes. The dehulled rapeseed is then cold-pressed in an extruder to obtain cold-pressed rapeseed oil. The resulting cake can be used as animal feed, as is the case with other byproducts of known methods. Alternatively, energy applications of the separated byproducts, particularly the husk component, are proposed.
[0017] The disadvantages of this known method are that, on the one hand, the drying of rapeseed must be carried out at a temperature below 40°C, thus requiring large space for the large drying equipment; and on the other hand, three components are generated when the dried rapeseed is crushed, and these three components must be separated. That is, the separation begins again in the crushed rapeseed after cleaning.
[0018] From the three components, only the useful fragments of hulled rapeseed are used. All other components of the rapeseed are removed along with the useful fragments of the husk, making the process uneconomical because a large portion of the rapeseed is not used to extract oil.
[0019] WO 2011 / 029611 A2 describes a method for processing rapeseed kernels, wherein the kernels are dehulled and separated into a kernel portion and a husk portion, wherein the kernel portion is subjected to one or more pressing operations for oil extraction. The method is carried out such that the cake containing solids and oil remaining during oil extraction is output directly or after a further grinding step as a raw material, filler, or mixture for human food. The cake with a small amount of husk can be ground when outputting the raw material for human food. The ground material can be deoiled by extraction and then used as a basis for protein concentration and / or protein separation.
[0020] A method for producing soybean protein concentrate from white soybean flakes is disclosed in WO 2011 / 161665 A1. The soybean flakes are extracted with hexane in a continuously operating hexane extractor for oil removal. After partial extraction with hexane, the flakes are converted in an aqueous ethanol extractor to extract the remaining hexane, sugars, and other alcohol-soluble materials.
[0021] US 4,158,656A discloses a method for producing a sterilized protein concentrate from defatted oilseeds, particularly rapeseed. In this method, the seeds of the oilseed fruit are dried to less than 6% moisture, dehulled, then further dried to 1 to 3% moisture and subsequently deoiled by hexane. The dehulled and deoiled seeds of the oilseed fruit are then extracted under non-oxidizing conditions with an aqueous alcohol solvent, preferably isopropanol containing additional bisulfite, and the extracted solid residue is dried at a temperature below 60°C.
[0022] A disadvantage of this known method is that the plant cells of the dehulled seeds are not broken down by compression, making oil extraction easier and more complete. Furthermore, hexane extraction begins directly on the dehulled seeds, which significantly makes thorough oil removal difficult and results in long extraction times. Additionally, high-quality cold-pressed rapeseed oil is not obtained, and antioxidants need to be added. Cold-pressed virgin oil is not permitted to contain these additives.
[0023] EP 1 228 701 A1 discloses a method for obtaining native organic matter, particularly oils, fats, waxes, pigments, vitamins, and / or other lipophilic substances and their derivatives, from a raw biological mass by means of centrifugation. For this purpose, the native product is crushed, lipophilic substances are extracted from the crushed native product using an extractant, and the paste is separated in a centrifugal field into an aqueous phase containing solid components and an organic liquid phase, said organic liquid phase containing hydrophobic substances.
[0024] A method for producing a protein supplement from rapeseed is disclosed in WO 2010 / 096943 A2, the method comprising: dehulling rapeseed kernels; mechanical deoiling, in which only a portion of the oil is separated, and the mechanical deoiling is carried out at a temperature below 80°C, averaging with respect to the duration of the extrusion process; and extraction. In the mechanical deoiling, carried out at a temperature below 80°C, averaging with respect to the duration of the extrusion process, only a portion of the oil is separated. In the extraction, protein foreign matter is removed from the protein powder. The extraction is carried out after processing with respect to kernel size in order to obtain granules at a predetermined kernel size distribution. Specifically, the known method begins with the dehulling of rapeseed kernels, which is performed by decomposition in a crusher and separation in an airflow in a sawtooth separator into a coarse component rich in kernels and a fine component rich in husks. The kernel component is then cold-pressed in a screw extruder at a temperature between 30 and 45°C to a residual oil content of approximately 23% by weight, wherein the cake is obtained in the form of bundles pressed together (referred to as cake pellets). The cake pellets are then deoiled in a Soxhlet extractor using hexane to a residual oil content of less than 3%. The solvent is then evaporated in an air stream at room temperature. The extracted protein powder pellets thus obtained are treated by percolation with an ethanol solvent without further grinding. The resulting finished protein concentrate is used with or without subsequent grinding.
[0025] WO 2010 / 096943 A2 relates to the drying of rapeseed during its storage at temperatures below 95°C, preferably below 40°C, wherein the purpose is to achieve enzyme inactivation and limited protein denaturation. However, temperatures below 40°C do not trigger either enzyme inactivation or protein denaturation. The rapeseed kernels are then broken down into kernel and husk components in a mill, wherein the husks are dispersed by bursting rather than by targeted crushing.
[0026] In mechanical deoiling performed at temperatures below 80°C, averaging the duration of the pressing process, the limiting temperature of 40°C in rapeseed oil is exceeded, which, according to general opinion, is followed for good cold-pressed rapeseed oil (http: / / en.foodlexicon.org / r0000680.php).
[0027] Besides direct application as a cake, the cake can also be pressed into granules at the output end of the screw extruder. Soft oilseeds, such as dehulled rapeseed, may be pressed slowly and inefficiently due to the lack of friction generated by the cake. When the output end of the screw extruder is partially closed by the granule die, the internal pressure and resistance within the screw extruder increase, so that the crushed, soft oilseeds can no longer be transported through the screw extruder. Consequently, a portion of the oilseeds and the pressed oil flow out through the screw extruder's screen and contaminate the oil.
[0028] As stated in WO 2010 / 096943 A2 itself, discoloration was already visible when the cake was extruded into spherical pellets with a residual oil content of less than 17%, indicating significant protein denaturation. Completely significant protein denaturation is eliminated when the cake, according to WO 2010 / 096943 A2, still has a residual oil content of only at least 10%.
[0029] To achieve the required kernel purity of less than 5% or 1% as specified in WO 2010 / 096943 A2, significant kernel loss must be accounted for during air classification, as lighter kernels are blown out along with a similarly weighted stack of shells. The portion of kernels blown out along with the shells is no longer supplied to the overall process and diminishes the profitability of this known method. Large-scale implementation of this known method has not yet been achieved.
[0030] Methods and components for obtaining oil from legume seeds and oilseeds are disclosed in DE 40 35 349 A1, which, in the case of rapeseed kernels, involves processing by plate production, followed by wetting the plates, then expanding them at 105 to 125°C, then cooling and drying at 100°C, and pressing at a temperature <100°C to a residual oil content of 15 to 25%. The cake produced during pressing is extracted at a temperature of approximately 65°C.
[0031] This known method involves unhulled legume seeds and oilseeds. The unhulled legume seeds and oilseeds undergo a puffing process at a temperature of 105-125°C without prior cold pressing. Oil extraction is performed only after the puffed material is cooled to 65°C. The puffing device thus facilitates oil extraction by breaking down cells through boiling.
[0032] The disadvantage is that this makes it impossible to produce high-quality cold-pressed kernel oil from legumes and oilseeds with few husks. Furthermore, protein denaturation occurs at the operating temperatures, making further cleaning and extraction of the proteins difficult.
[0033] Methods and apparatus for heat-treating oilseeds and oil fruits, particularly legume seeds, are disclosed in DE 35 29 229 C1 to obtain, on the one hand, oil and fat, and on the other hand, oil-free or fat-free crumbs suitable as concentrate feed. Here, the purified, dried, and crushed oilseeds and oil fruits, after previous flattening, are briefly heated to a temperature greater than 105 to 148°C in an airless or oxygen-free atmosphere under pressure exceeding atmospheric pressure, and then suddenly depressurized while cooling to a temperature below 100°C. This results in the urease activity in the crumbs being largely inhibited, and the overall protein content and its water solubility being largely preserved. The heat treatment can then be carried out before pressing and before extraction, during which the extraction temperature is adjusted to 50 to 65°C. Specifically for rapeseed, the flattened kernels are first heat-treated under relatively warm conditions, then the warm material is pressed while obtaining rapeseed oil, and the pressed cake is heat-treated again under increased temperature conditions, cooled, and finally extracted in a known manner. This should enable the selective acquisition of the oil content of the shell and the pure separation and pressing of rapeseed oil from the kernel, as well as the extraction of oil from the shell.
[0034] This known method uses only unhulled oilseeds. Swelling replaces the boiling process prior to extraction. High-quality cold-pressed kernel oil cannot be obtained. High temperatures in the case of rapeseed cause protein denaturation.
[0035] EP 2783576 A1 describes a method for producing rapeseed protein concentrate by processing rapeseed kernels. The kernels are dehulled to obtain a rapeseed kernel component. The rapeseed kernel component is partially deoiled in a screw extruder. Five to 60% of the resulting protein-containing cake is returned and mixed with the rapeseed kernel component before the screw extruder to increase friction and pressure in the screw extruder. The residue of the protein-containing cake is washed with an aqueous alcohol solution to at least partially remove sugars, tannins, sinapic acid, and gluconates, and to produce a rapeseed cake protein concentrate with a residual oil content of 5 to 25% (w / w). The rapeseed cake protein concentrate is dried at a temperature in the range of 60 to 120°C until the water content of the rapeseed cake protein concentrate is less than 10%. The rapeseed kernel component may have been previously heated to 70°C.
[0036] It is not known from EP 2783576 A1 how to add the cake directly or crushed to the rapeseed kernel component and how to thereby increase the extrusion efficiency.
[0037] When pressing rapeseed that has never been hulled to extract oil, the shell content is approximately 15%. During pressing in a screw press, friction is generated through the shell, which is necessary to generate high pressure and thus achieve high pressing efficiency. Since EP2783576 A1 specifies a shell content of 1 to 10% for the rapeseed kernel fraction, it is concluded from the amount of cake returned that increasing friction through returned cake is not very efficient. A favorable specific return ratio is given as 1:0.25, where the cake is heated to 70°C before pressing. Here, 1 ton of rapeseed kernel fraction yields 250 kg of cake, which represents approximately 20% of the cake in the mass to be pressed, corresponding additionally to 1 to 10% shell. In other words, 20% of the cake compensates for approximately 5 to 10% of the shell loss that occurs during kernel hulling.
[0038] A significant disadvantage is the risk of bacterial growth in the screw extruder due to the constantly returning patties. The patties are kept at such low temperatures that pasteurization is not performed. This bacterial growth in the screw extruder leads to toxin contamination of the patties and the spread of bacteria and toxins throughout all products produced by known methods.
[0039] Even when the microorganisms in the extruded cake are eliminated through alcohol-water extraction, there is still a risk of toxin contamination. To eliminate both microbial and toxin contamination, the screw extruder typically needs to be cleaned and sterilized, which means production must be stopped accordingly. This limits the industrial applicability of this known method.
[0040] Additionally, the protein content of the rapeseed cake protein concentrate does not meet the definition of a protein concentrate derived from soybean protein concentrate, which requires a protein content of greater than 60% with respect to dry matter. This is due to the lower protein content of the rapeseed cake protein concentrate, which only pertains to rapeseed protein powder. Summary of the Invention
[0041] The objective of this invention is to provide a stable, reproducible, and continuous method and apparatus for carrying out the method, by which a protein-containing product is obtained from rapeseed in addition to high-quality cold-pressed rapeseed oil at a low cost, the protein-containing product being further processed into high-quality feed and food, wherein the large-scale feasibility of the method and apparatus is ensured.
[0042] The objective of this invention is achieved by a method and an apparatus having the features of the present invention. Preferred embodiments of the method and apparatus according to the present invention are determined in the following description.
[0043] In the method for processing rapeseed kernels according to the invention, the kernels are dehulled, wherein the kernels are guided through the gap between dehulling rollers, and the husks are separated from the fractional kernels by sieving and / or air separation, such that the total amount of husks remaining in the fractional kernels does not exceed 4% by weight of the fractional kernels. Cold-pressed rapeseed oil is extracted from the fractional kernels, wherein the water content of the fractional kernels is 4%-7% by weight, wherein the temperature of the resulting cake is limited to 70°C, and wherein the first residual oil content is reduced to 18%-28% by weight of the dry mass of the cake. Pressurized steam is supplied to the cake, and the cake is then expanded into collets, wherein the steam is metered such that the cake is temporarily heated to over 100°C by the steam, and the collets have a temperature of 80°C to 95°C after expansion. The expanded body is extracted using an organic solvent, wherein the secondary residual oil content is reduced to 2% by weight of the dry weight of the expanded body or less. After expansion, a portion of the expanded body is transported back, mixed with a less-hulled seed component before pressing, and pressed again.
[0044] In the method according to the invention, the friction of the less-hulled seed component during pressing is increased by retrieving a portion of the expanded body, thereby facilitating, at least significantly, limiting the cake temperature in the resulting cake to 70°C, even though the first residual oil content is reduced to 18%-28% by weight of the dry weight of the cake. The retrieving of the portion of the cake may also be necessary so that the overall cake temperature in the resulting cake can be limited to 70°C, even though the first residual oil content is reduced to 18%-28% by weight of the dry weight of the cake.
[0045] In the method according to the invention, the rapeseed kernels are dehulled before pressing to produce cold-pressed rapeseed oil. Accordingly, the cake obtained by pressing and the expanded body obtained by expanding the cake also have only a small amount of shell. This results in a significant increase in the value of the expanded body, in addition to a certain improvement in the quality of the cold-pressed rapeseed oil. The expanded body can already be used as animal feed. The cake is heated for pressing, which is not a concern hygienically, and although the heating is brief, it retains a favorable amino acid composition with minimal undesirable denaturation at any time.
[0046] The expansion body, in particular, has an interconnected yet open structure that facilitates its further processing as described below, a structure that can be obtained through processing the expansion body.
[0047] According to the method of the invention, if necessary, the rapeseed kernels can be cleaned to remove impurities such as stones or chaff. The cleaned kernels can then be sorted according to kernel size to separate kernels unsuitable for subsequent hulling. Specifically, kernels with a minimum size between 1.2 mm and 1.8 mm, preferably about 1.4 mm, and kernels with a maximum size between 2.6 mm and 3.0 mm, preferably about 2.8 mm, can be separated. Kernels exceeding the maximum size can be hulled by separation using a device matching their kernel size, and kernels smaller than the minimum size are used separately. Typically, the content of small kernels is less than 8% by weight, usually less than 4% by weight.
[0048] The kernels used for hulling have been previously or subsequently adjusted to a moisture content between 4% and 7% by weight, preferably about 5% by weight, and are dried as needed. The drying temperature should be selected, if necessary, such that the kernel temperature does not exceed 70°C, preferably 65°C, to avoid protein denaturation during drying. The kernels are guided through the gap between the hulling rollers to crush the husks, the gap typically being at least 20% smaller than the minimum kernel size. The kernels may also pass sequentially through multiple roller gaps having progressively decreasing sizes.
[0049] The crushed kernels between the dehulling rollers are then separated into a low-hulled kernel component and a high-hulled kernel component by sieving and / or air separation (for which the husks are also removed). The total husks remaining in the low-hulled kernel component shall not exceed 4% by weight. Preferably, the husks shall not exceed 3.5% by weight.
[0050] During wind separation, the productivity of the low-hulled grain component can typically reach greater than 75% and preferably about 80%. The high-hulled grain component complements the low-hulled grain component, so that the productivity of the high-hulled grain component is between 20% and 25% of the rapeseed used.
[0051] The kernel is also present in the husk-rich grain component, which can comprise up to 40% by weight of the husk-rich grain component. Therefore, the husk-rich grain component is meaningfully further processed. This can be done by known methods, such as oil pressing at temperatures exceeding 90°C, or, in particular, solvent extraction of the husk-rich grain component using hexane. Alternatively, the husk-rich grain component can be incorporated with water at approximately 20 to 30°C, i.e., room temperature or approximately 25°C, which triggers the swelling of the fibers contained in the kernel and thereby floats the kernel to obtain a further fraction of the husk-rich grain component.
[0052] Based on other morphological factors, swelling in the fibers contained within the shell does not occur, or at least not to the same degree. Furthermore, the kernel differs from the shell in its higher oil content. After swelling of the fibers in the kernel, the kernel has a density lower than water, while the shell has a density higher than water. Accordingly, the kernel is flotated, wherein the flotation and the resulting separation of the kernel from the shell can be supported by introducing fine air bubbles and / or gentle, non-shredding agitation. The flotated kernel is received as a further fraction of the seed grains with fewer shells. This further fraction of the seed grains can be dehydrated by a belt extruder and added to the previously separated fraction of the seed grains. This addition can be done before, but also after, pressing to produce cold-pressed rapeseed oil. Preferably, the further fraction of the seed grains is introduced into the main feed stream, but only before the delivery of pressurized steam and subsequent expansion into an expanded mass. The separated shell component can be separated based on its density higher than water, further purified, and then utilized, for example, thermally or in a biogas generator.
[0053] After dehulling and before pressing, the partially hulled grain component can be rolled into flakes and guided through at least one roller gap formed by a rolling roller. Here, the temperature of the flakes is kept below 45°C. The flakes preferably have a thickness of 0.1 to 0.8 mm.
[0054] The pressing of the less-hulled seed fraction is carried out without the input of additional heat. The processing during pressing also results in a temperature increase. This temperature increase is limited according to the invention to a maximum cake temperature of 70°C in the resulting cake. This reliably follows and is generally well below the 0.2% trans fatty acid content of cold-pressed rapeseed oil.
[0055] During pressing, cold-pressed rapeseed oil can be collected as a first oil fraction and a second oil fraction. The first oil fraction is heated during pressing to a temperature not exceeding a first limit temperature, while the second oil fraction is heated during pressing to a temperature exceeding the first limit temperature. The first oil fraction has minimal thermal impact on its oil composition and is rapeseed kernel oil of the highest quality obtained according to the method of the invention. The second oil fraction is also high-quality cold-pressed rapeseed kernel oil according to Codex Alimentarius. A third oil fraction may also be collected, which is heated during pressing to a temperature exceeding a second limit temperature. The first limit temperature between the first and second oil fractions can be between 35 and 50°C. Preferably, the first limit temperature is about 40°C. At a maximum cake temperature of 70°C, the first oil fraction has an average temperature of 32 to 36°C and significantly less than 0.1% trans fatty acids, while the second oil fraction has an average temperature of 40 to 50°C and at least significantly less than 0.2% trans fatty acids. The second limit temperature between the second oil fraction and the possible third oil fraction can be about 60°C.
[0056] When pressed according to the present invention at a pressing temperature not exceeding 70°C, the hulled seed component can be pressed to a first residual oil content of 18%-28% by weight or 20%-24% by weight, i.e., approximately 22% by weight. Cold-pressed rapeseed oil can be processed in a conventional manner by filtration and / or sedimentation to provide cold-pressed, virgin rapeseed kernel oil that meets food quality standards.
[0057] Traditional screw presses for oil extraction are designed for efficiency, meaning the screw pressure should achieve the highest possible productivity. However, power reduction occurs in screw presses due to the dehulling of the kernels and the resulting lack of husks. This power reduction decreases the productivity of cold pressing oil with fewer husks compared to regular cold pressing and leads to higher costs, as larger screw presses with higher power consumption are required. Furthermore, the high power consumption also necessitates more intense heating of the material within the screw press.
[0058] To improve the efficiency and thus economics of cold pressing of low-hulled oil using a screw press, a portion of the cake is added to the low-hulled seed component before pressing in the method according to the invention, thereby increasing friction during pressing. This return portion, in the method according to the invention, is not associated with the risk of bacterial growth in the screw press because the returned portion of the cake is distributed only after expansion, and thus only after the cake has been sterilized by added steam. In other words, the returned portion of the cake according to the invention is a portion of the expanded body formed by expansion, which is non-bacterial due to heat processing and is not a hygiene concern. The efficiency data of conventional cold pressing of oil is achieved by adding the expanded body to increase friction during cold pressing. Furthermore, the mechanical properties of the expanded body are more favorable for improving pressing efficiency compared to the mechanical properties of the cake before expansion.
[0059] Advantageously, the returned portion of the cake or expander is cooled to a temperature of 20 to 35°C and preferably 25 to 30°C, i.e., about room temperature, before being added to the hulled grain component, and thus can be fixed and deformed with minimal deformation.
[0060] The portion of the cake or expanded material that is returned has a maximum particle size of 4 to 6 mm, preferably 5 mm. That is, the returned portion can be particularly fine portions and fragments of the expanded material. Depending on the shell content, the returned portion of the cake or expanded material replaces the previously separated shells, so the returned portion can total up to 20% of the mass of the cake or expanded material and thus also to be pressed. Depending on the type of pressing, the portion of the cake or expanded material that is meaningfully returned may exceed 5% and is typically between 10% and 15%.
[0061] Not only are the expanded bodies produced directly from the pressing cake suitable for repatriation and increase friction when pressing the less-hulled kernel fraction, but the expanded bodies remaining after extraction with the aid of organic solvents to reduce the residual oil content are also suitable for screening out, drying, and repatriation for pressing, even if the maximum size is 5 mm.
[0062] Surprisingly, the expanded body increased friction and thus improved the pressing efficiency of cold oil without reducing the quality of the extracted oil. Specifically, it increased productivity and pressing efficiency at a constant current consumption and also limited the cake temperature, as less mechanical power was converted into heat.
[0063] The cake obtained by pressing can be crushed or used directly, and additional low-hulled grain components obtained by flotation or additional low-hulled grain components remaining after pressing can be added to the cake.
[0064] The briquettes are conveyed to an expander / extruder for steam infusion and subsequent expansion. With the addition of pressurized steam, the material is compressed and temporarily heated to over 100°C, typically up to 140°C, before expansion, and then cooled by depressurizing the steam. The steam volume can be adjusted so that the expanded body temperature is between 80 and 95°C after expansion.
[0065] The resulting expanded body, unlike spheroids (which can be compressed into spheroids after pressing), has an open porous structure that facilitates further processing. A brief temperature increase, exceeding 100°C and reaching a maximum of 140°C, generated by steam and pressure, inhibits enzymes and Salmonella and firmly and elastically stabilizes the hygienic porous structure, thereby enabling the expanded body to be used as a substitute for the shell in cold pressing. Furthermore, the brief temperature increase causes partial denaturation of the proteins contained within the expanded body. This partial denaturation does not significantly limit the feed or nutritional value of the proteins. Typically, the expanded body produced according to the invention reduces the protein solubility by no more than 20% compared to the pressed cake. However, this partial denaturation results in the proteins remaining in the expanded body and not disappearing during subsequent extraction to remove other oils and unwanted inclusions. When the protein denaturation of the expanded body is small compared to that of the pressed cake, and the protein solubility, as measured by NSI (Nitrogen Solubility Index) or PDI (Protein Dispersibility Index), is not less than 80% of the protein solubility in the pressed cake, then the amount of water vapor and the temperature at which it is generated have been properly regulated.
[0066] The expanded body is extracted using an organic solvent to reduce it to less than 2% by weight of its dry weight, or a second residual oil content of 0.3%–1.3% by weight. Any other organic solvent that readily dissolves the oil, such as isopropanol, can be used besides hexane. Azeotropic or pure alcohols in the form of ethanol can also be used. Here, the alcohol can be, in particular, bioethanol, thereby producing a bio-rapeseed protein product during the processing of bio-rapeseed.
[0067] The extraction can be performed using industrial standard techniques, particularly carousel extraction or belt extraction, as in all the foregoing steps of the method according to the invention. The solvent used surrounds the expanded body during percolation, wherein an oil-solvent mixture is produced by the solvent, and the oil contained in the expanded body is dissolved in the oil-solvent mixture. The solvent is separated from the oil-solvent mixture by distillation in a known manner, leaving the oil. The oil is the extracted rapeseed kernel oil.
[0068] The extracted expanded body can be dried and crushed, wherein the high-protein rapeseed protein powder has a protein content of more than 45% by weight, preferably more than 48% by weight, in dry weight, and the rapeseed protein powder is almost shell-free, similar to HP soybean powder. The rapeseed kernel powder can be further processed using known techniques.
[0069] Possible processing of the expanded body after extraction with organic solvents and drying is an alcohol-water extraction to remove non-protein contents and to concentrate the protein into rapeseed protein concentrate.
[0070] Therefore, the expanded material is first sieved to separate the fine fraction from the expanded material fragments, which are inevitably generated during drying due to mechanical load. If the fine fraction is used to improve friction during cold pressing, a sieve that retains particles larger than 5 mm is selected, and the material is further processed during alcohol extraction to reach a rejection limit of 1 mm.
[0071] The expanded body, reduced to a fine fraction, is then subjected to swelling in an alcohol-water mixture for 15 minutes, which is sufficient for this purpose. The saturated expanded body, after passing through the alcohol-water mixture, is then conveyed to a newer belt extraction device. This swelling should be non-destructive, and the belt extraction can be carried out similarly to extraction using organic solvents. A suitable and simple embodiment is that a spiral swelling device is belt-connected before the extraction device to allow for continuous swelling. However, all other techniques for achieving continuous swelling are also suitable.
[0072] Swelling can be driven by an alcohol-oil solvent mixture extracted using an alcohol belt, a process corresponding to distillation. The spiral swelling device then leads to another extraction stage.
[0073] Alternatively, the expanded body extracted with organic solvents can be processed directly, i.e., without drying and / or crushing.
[0074] Therefore, to avoid damaging the structure of the expanded body and thus creating fine fractions, the expanded body can be dried by a simple discharge device and the dripping of organic solvent before being discharged from the solvent-extraction device. Typically, more than 50% of the solvent can be removed from the expanded body in this manner. At the output of the solvent-extraction device, the expanded body is received without damage by a conveyor unit and transported out, for example, by a screw conveyor or conveyor belt. The conveyor unit conveys the solvent-wet expanded body undamaged to a filter, which further subdivides it in a partitioned area. The material is transferred onto the filter without damage. The filter can be a closed rotary filter or a belt filter, particularly a vacuum belt filter. An impeller gate can be installed between the conveyor unit and the filter to separate the solvent areas. After the solvent-wet expanded body is arranged on the filter, the filter is placed in a first position in which the solvent content of the solvent-wet expanded body is further reduced. This can be accelerated by applying a vacuum to a vacuum belt filter. Solvent contents of less than 40% by weight can thus be achieved. Here, the solvent is concentrated in the filter by capillary action, thus forming a low-solvent layer in the capillaries of the expander, which merely wets the surface of the capillaries. When the organic solvent is hexane, pure ethanol or a water-ethanol-azeotrope can be applied from the second position of the filter to displace the hexane. The layer produced by the solvent in the expander results in a nearly flat alcohol / hexane boundary layer, thus producing only a small hexane / ethanol / water mixture. After two to three washing stages, the hexane is replaced by ethanol without residue in the structure of the expander. Only a small volume of the hexane / ethanol mixture is present here, which can be treated separately by distillation. This example is exemplary. Any other technical means for achieving solvent replacement can be used.
[0075] Following solvent replacement, the swollen body can be extracted using an aqueous alcohol solution to obtain a purified rapeseed protein concentrate. Here, the aqueous alcohol solution can have 70%-96% by volume of ethanol. 80%-90% by volume is preferred. Specifically, this alcohol extraction with ethanol is used to remove toxins and other anti-nutritional inclusions. In the preferred alcohol concentrate, the swelling of the fibers contained in the rapeseed material and the resulting volume increase are kept to a minimum. This also prevents a drastic decrease in the permeability of the swollen body due to swelling. Excessive swelling can cause capillary closure of the swollen body.
[0076] Preferably, the expanded material is extracted in convection using an aqueous alcohol solution. Here, the solid-to-solvent ratio is meaningfully between 1:2 and 1:6. Preferably, at least 10 extraction stages are performed in the convection. At the end of extraction, displacement washing can be carried out using azeotropic ethanol, i.e., 96% ethanol, to facilitate drying of the extracted material. The extract from the extraction stages is collected. After alcoholic distillation, the rapeseed-molasses remains.
[0077] The azeotropic water-ethanol solution can be collected separately and used to replace hexane with ethanol in the solvent exchange zone. Advantageously, the recovery of the alcohol-water mixture from the alcohol-water extraction does not require distillation and can thus be kept compact. Distillation is maintained in small volumes for solvent exchange of the separated hexane-ethanol-water mixture.
[0078] Alcohol extraction can also be carried out by creating a suspension through grinding in an aqueous alcohol solution. The suspension is then cleaned in convection using a centrifuge. This can be done as a standalone aqueous alcohol extraction or as a follow-up process to an existing belt extraction. Vacuum belt extraction is also suitable for alcohol washing of suspensions.
[0079] Suspension washing is particularly suitable for reprocessing after a set-top box extraction, as various contaminants are fixed within the expanded body and released only when the expanded body is opened. Thus, suspension washing achieves fine purification, thereby improving the quality of protein concentrates and protein content.
[0080] Purified rapeseed protein concentrate can be dried by baking, rapid drying, or vacuum drying. The dried rapeseed protein concentrate has a protein content of more than 60% by weight of its dry material.
[0081] In an apparatus according to the invention for implementing a method for processing rapeseed kernels according to the invention, the apparatus comprises: a dehulling roller forming a gap for dehulling the kernels; a separation device connected downstream of the gap, the separation device having at least one sieve or air classifier for separating a low-hulled kernel component from a high-hulled kernel component; a flaking roller for crushing the low-hulled kernel component into flakes; a screw extruder for pressing cold-pressed rapeseed oil from the flakes, wherein the screw extruder outputs a cake; a return device configured to return a portion of the cake to the screw extruder; an expansion device connected downstream of the screw extruder for supplying pressurized steam to the cake and then expanding the cake into an expanded body; an extraction device connected downstream of the expansion device for extracting the expanded body using an organic solvent; and a return device configured to return a portion of the cake, i.e., in the form of an expanded body, after the expansion device.
[0082] The return device can be specifically configured to separate the returned portion of the cake by sieving from the expanded body to obtain particulate components with a maximum particle size in the range of 4 to 6 mm. This sieving can be performed before and / or after extraction in an extraction device using an organic solvent.
[0083] The return device may include a cooling unit configured to cool the portion of the pressed cake. The cooling unit may, for example, include a cooling fan that cools the portion of the pressed cake by evaporative cooling based on the evaporation of the contained moisture.
[0084] A screw extruder may have an extrusion screw rotating about a horizontal axis of rotation and a screen cover, wherein a weir extending transversely to the axis of rotation is movable in the direction of rotation within an oil collection trough arranged below the screen cover. The weir separates the first pressed oil component and the second pressed oil component of cold-pressed rapeseed oil in the oil collection trough from each other. The aforementioned first limiting temperature between the first and second oil components can be adjusted by moving the weir. When a drive device is provided that moves the weir in the direction of rotation based on a signal from at least one oil temperature sensor arranged on the weir, the first limiting temperature can be adjusted to a predetermined value, even if the temperature distribution is altered by the screw extruder. The screen cover of the screw extruder may be constructed of a screen bar.
[0085] Furthermore, the apparatus according to the invention may include a flotation cell to separate the shell-rich grain component into a separate, less-shelled grain component and a shell component by flotation in water. Here, the flotation cell may optionally have a compressed air inlet and / or a stirrer leading to its bottom or vicinity.
[0086] An extraction device connected downstream of the expansion unit can also be configured to dry the expanded body or to allow the solvent-wet expanded body to undergo solvent replacement and then extract the expanded body using an aqueous alcohol solution.
[0087] Advantageous further aspects of the invention are derived from the claims, the description, and the drawings. The advantages of features and combinations of features described in the description are merely exemplary and may work alternatively or supplementarily, and these advantages are not necessarily enforceable by embodiments according to the invention. Without altering the subject matter of the appended claims, the disclosure of the original application and patent applies as follows: additional features are known from the drawings, particularly the geometry shown and the relative dimensions of the components relative to each other, their relative arrangement, and their function. Features of different embodiments of the invention or combinations of features of different claims may be similarly different from and inspired by the backreference relationship of the claims. This also applies to features shown in separate drawings or mentioned in the description of those drawings. These features may also be combined with features of different claims. Similarly, features listed in the claims may be omitted for use in other embodiments of the invention.
[0088] In the claims and specification, the quantity of a feature is understood to mean that there is exactly one or more of the stated quantity, without necessarily using the adverb "at least". That is, when, for example, a screw press is mentioned, it is understood that there is exactly one screw press, two screw presses, or more screw presses. The stated feature may be supplemented by other features or may be the only feature, and the corresponding product is constituted by said feature.
[0089] The reference numerals included in the claims do not limit the scope of the subject matter protected by the claims. These reference numerals are used merely to facilitate the understanding of the claims. Attached Figure Description
[0090] The present invention will be further illustrated and explained below with reference to the preferred embodiments shown in the accompanying drawings.
[0091] Figure 1 A block diagram illustrating an apparatus according to the invention and a method according to the invention is shown.
[0092] Figure 2 A preferred embodiment of the screw extruder according to the invention is shown. Detailed Implementation
[0093] Figure 1The apparatus 1 according to the invention and the process of the method according to the invention are illustrated in block diagram. Rapeseed from silo 2 is sorted and cleaned in screening equipment 3. Cleaned kernels 4 within a pre-defined kernel size range are obtained from screening equipment 3. After drying, if possible, to adjust the moisture content of the kernels 4 to approximately 5% by weight, the kernels 4 are dehulled by dehulling rollers 5, which form a roller gap, and a separating device is connected downstream of the dehulling rollers. The result is a low-hulled kernel component 6 and a high-hulled kernel component 31. The low-hulled kernel component 6 is crushed into flakes by a flaking roller 7. Cold-pressed rapeseed oil 25 is pressed from the flakes by a screw extruder 8. The resulting cake 9 is conveyed to an expansion device 14.
[0094] The husk-rich grain component 31 is mixed with water to form a suspension 32, in which the fibers contained in the kernel portion of the husk-rich grain component 31 swell. Flotation 33 is then performed, during which the remaining husk-less grain component 10 floats and is thus separated from the husk component 11. The husk component 11 can be dried and / or ground and utilized, for example, in a combustion device or biogas generator. The remaining husk-less grain component 10 is pressed in a belt extruder 12. Its solid portion is added to the cake 9 before the expansion unit 14. The water pressed out by the belt extruder 12 is treated in an oil clarifier 13, where oil 26 is separated. The purified water is treated with UV (ultraviolet) for sterilization and then reused. The cake 9 and the remaining husk-less grain component 10 are then crushed and thus conveyed to the expansion unit 14. In the expansion unit 14, the temperature of the cake 9 is temporarily increased to over 100°C, typically up to 140°C, by conveying pressurized steam. Upon exiting the expansion unit, the steam is depressurized, and the material exiting as expanded body 46 is cooled to 80 to 95°C. The expanded body 46 first undergoes solvent extraction 16 in the extraction unit 15 using a solvent such as hexane. After solvent replacement 17, aqueous alcohol extraction 18 is performed. Alternative solvent replacement may be performed by drying the solvent-extracted expanded body 19. This can then be followed by further expansion into granules 20 or by drying the material, or rapeseed protein powder produced by drying 19 may be output as a product.
[0095] Alcohol extraction 18 can also be carried out on the expanded body or rapeseed protein powder produced by drying 19. Rapeseed oil 27, extracted from the oil-solvent mixture of solvent extraction 16, is obtained in distillation 21. The solvent in solvent replacement 17 is recovered and reused in distillation 22. Molasses 28 is produced from the distillation 23 of the alcohol extract of alcohol extraction 18. Drying 24 of the residue of alcohol extraction 18 yields a purified rapeseed protein concentrate 29.
[0096] The return device 34 returns a portion of the cake 9, which is at the output of the expansion device 14 after expansion, to the screw extruder 8. Specifically, the fine portion of the expanded material 46 output from the expansion device 14 is screened out, cooled to a temperature <35°C by the cooling device 35 of the return device 34, and then added to the crushed low-husk grain component 6 to increase friction in the screw extruder 8. A certain amount of friction between the pressed low-husk grain component 6 and the screw extruder 8 is necessary to achieve sufficient pressing efficiency and residual oil content in the cake 9 produced in the screw extruder 8, with respect to the mechanical energy used and thus also to the heating of the cake 9 produced in the screw extruder 8. This friction is provided by the cooled expanded material, without causing hygiene problems due to the portion of the cake 9 returned to the screw extruder 8, because the expanded material 46 is sanitized by expansion in the expansion device 14. Furthermore, the expanded material 46 has better mechanical properties for increasing friction in the screw extruder 8 compared to the cake 9 before the expansion device 14.
[0097] The screw extruder 8 according to the device 1 of the present invention Figure 2 The embodiment shown has an electrically driven device 36 that rotates an extrusion screw 37 about a horizontal axis of rotation 38 relative to a screen 39 to press rapeseed oil 25 from the hulled component 6, producing a cake 9. Here, a first oil component 42 is first pressed in the direction of the axis of rotation 38, in which the rapeseed oil 25 does not exceed a limiting temperature. A second oil component 43 is then pressed, which is always still composed of cold-pressed rapeseed oil 25 because no heat is transferred to the screw extruder 8. However, the action of the extrusion screw 37 on the hulled kernel component 6 causes the temperature in the screw extruder 8 to rise along the axis of rotation 38. The maximum cake temperature of the cake 9 is limited to 70°C. Thus, the second oil component 43 also has a trans fatty acid content of less than 0.2%. The trans fatty acid content of the first oil component 42 is less than 0.1%. The two oil components 42 and 43 are separated in an oil collection trough 40 arranged below the screen 39 by a weir 41 extending transversely to the axis of rotation 38. The weir gate 41 is moved along the axis of rotation 38 by the drive device 44 shown here by double arrows, according to the oil temperature sensor 45 arranged on the weir gate 41, so that the oil temperature sensor 45 detects no temperature higher than the limit temperature of the first oil component 42.
[0098] Example
[0099] Ten tons of rapeseed, such as double-zero rapeseed, are cleaned. Depending on the degree of contamination, 2 to 3% of the virgin quality is removed. During subsequent sorting, up to 4% of the kernels with sizes smaller than 1.6 mm and larger than 2.8 mm are removed. 94% of the virgin rapeseed, with a moisture content between 7 and 9%, is then conveyed to a drying unit.
[0100] Rapeseed is dried to 5% by weight moisture content at 60-70°C and then cooled to 30°C before being fed to hulling roller 5. Separation into a hull-rich kernel component 31 and a hull-poor kernel component 6 achieves a yield of approximately 80% by weight of the hull-poor kernel component and 20% by weight of the hull-rich kernel component 31. The hull-rich kernel component 31 contains 30%-40% by weight kernel material, while the hull-poor kernel component 6 comprises less than 4% hull. The hull-rich kernel component 31 contains a total of approximately 20% by weight oil and 16% by weight protein. The hull-rich kernel component 31 is incorporated with water at 20-30°C. A 1:6 ratio is achieved in the mass fraction, meaning that at least 6 kg of water is allocated to 1 kg of hull-rich kernel component 31. After the water is added, the resulting suspension 32 is in motion and fully mixed by gentle, uninterrupted stirring. The kernel fibers in the husk-rich kernel component 31 swell within 15 minutes. Subsequent flotation 33 of the stirred husk-rich kernel component results in separation into a separate, less-husk kernel component 10 and a husk component 11. Finely distributed air can be blown in to enhance flotation. The swollen kernels of the less-husk kernel component 10 are collected via a belt extruder 12. Water is separated and transported in a circulation line to a new husk-rich kernel component 31. The less-husk kernel component 10 collected via the belt extruder 12 is dehydrated and added to the cake 9 before the expansion unit 14.
[0101] The hulled seed component 6 is then pressed into flakes by the milling roller 7. The hulled seed component 6 is pressed so forcefully that the temperature of the flakes is kept below 45°C. The milling roller 7 can be cooled to maintain this temperature. The flakes are fed directly to a screw extruder 8. In the screw extruder 8, the flakes are compressed by the extrusion screw 37. The output cold-pressed rapeseed oil 25 is collected separately according to temperature range. The first oil component 42, with a temperature of 35 to 40°C, is virgin, cold-pressed rapeseed oil and has less than 0.1% trans fatty acids. The second oil component 43, between 45 and 60°C, is virgin, cold-pressed rapeseed oil 25 and has less than 0.2% trans fatty acid content. The two oil components together produce approximately 2.8 tons of cold-pressed rapeseed oil 25, of which 40% is virgin rapeseed oil and 60% is virgin cold-pressed rapeseed oil. The cake 9 output from the screw extruder 8 has a residual oil content of 22%-23% by weight.
[0102] The pressed cake 9 is crushed, and a further fraction of the hulled seed component 10 from the belt extruder 12 is added to the pressed cake, which is then conveyed to the expansion unit 14. In the expansion unit 14, the pressed cake is heated with pressurized steam 30 so that it reaches a temperature between 80 and 95°C after exiting the expansion unit 14, producing an expanded body 46. The expanded body 46 is cooled. Fine fractions and debris with particle sizes up to 5 mm are sieved from the expanded body 46. The content of the fine fraction is 3%-6% by weight. 5%-20% by weight of the expanded body is conveyed as fine fractions and debris to the hulled seed component 6 before the screw extruder 8 to increase friction during cold pressing of rapeseed oil 25.
[0103] The expanded bodies 46, larger than 5 mm, are extracted in a carousel-type extraction device of extraction apparatus 15 by multi-stage convective percolation with hexane at 60°C. The resulting oil-solvent mixture is distilled and the hexane is reintroduced into the process. The extraction time is between 1 and 3 hours, preferably about 2 hours. 1.1 tons of extracted rapeseed oil 27 is produced.
[0104] After extraction 16, the hexane-coated wet expanded body 46 is drained and dehumidified. Then, the expanded body 46 can be dried 19 to produce rapeseed protein powder with high protein content or transported to solvent replacement 17.
[0105] If drying 19 of the hexane-wet expanded body 46 is selected, the dried expanded body 46 can be ground into protein powder or first sieved through a 1 mm sieve to reduce the fine fraction. The expanded body 46, after the fine fraction has been removed, is then conveyed to a spiral swelling device. The spiral swelling device conveys the expanded body and transfers the expanded body 46 to a belt extraction device 18 for extraction with an aqueous alcohol solution, i.e., 80% alcohol.
[0106] Solvent replacement 17 is carried out, specifically by means of a vacuum belt filter. After continued feeding, the contained hexane is applied with 96% ethanol. During this process, ethanol is drawn in through an expansion body, where it is conveyed in convection. After three cycles, the hexane is replaced with ethanol, and the expansion body is then applied with 80% ethanol and swells in convection for 15 minutes. The ethanol solution (molasses 28) output from the subsequent ethanol extraction 18 is used for swelling. The swollen material is drained, loosened, and conveyed to the belt extraction unit of the subsequent ethanol extraction 18, where the expansion body is further extracted with 80% ethanol for 1 to 3 hours. The final ethanol stage can replace the ethanol-water mixture with 96% ethanol to reduce the energy cost of the subsequent drying 24. The azeotropic ethanol can also be used to replace the hexane in solvent replacement 17. The advantage achieved here is that only a small amount of solvent is distilled in distillation 22.
[0107] The alcohol extracted from 18 was distilled and reused. Molasses 28 was left. The dry weight of molasses 28 corresponds to approximately 10 to 12% of the rapeseed being processed. The rapeseed protein concentrate 29 purified by the alcohol extraction was dried and yielded 3 tons.
[0108] Rapeseed protein concentrate 29 contains the following components:
[0109]
[0110] An exemplary amino acid composition shows a structure similar to that of rapeseed:
[0111]
[0112] Exemplary oil analysis reveals a composition similar to that of rapeseed:
[0113]
[0114] List of reference numerals
[0115] 1 device
[0116] 2 silos
[0117] 3-screen equipment
[0118] 4 seeds
[0119] 5 shelling rollers
[0120] 6. Low-hulled grain components
[0121] 7 grinding rollers
[0122] 8-screw extruder
[0123] 9 Pressed cakes
[0124] 10 Other low-hulled grain components
[0125] 11 shell components
[0126] 12-belt extruder
[0127] 13 Oil Clarifier
[0128] 14 Expansion Device
[0129] 15 Extraction Device
[0130] 16 Solvent Extraction
[0131] 17 Solvent Replacement
[0132] 18% alcohol extraction
[0133] 19 Drying
[0134] 20 spherical particles
[0135] 21 Distillation
[0136] 22 Distillation
[0137] 23 Distillation
[0138] 24-hour drying
[0139] 25 Cold-pressed rapeseed kernel oil
[0140] 26 oil
[0141] 27. Extraction of rapeseed kernel oil
[0142] 28 Molasses
[0143] 29. Purified rapeseed protein concentrate
[0144] 30 water vapor
[0145] 31. Grain components rich in husk
[0146] 32 suspension
[0147] 33 Flotation
[0148] 34 Return Device
[0149] 35 Cooling device
[0150] 36 drive units
[0151] 37 Extrusion Screw
[0152] 38 axis of rotation
[0153] 39 sieve cover
[0154] 40 oil collection tank
[0155] 41 Weir
[0156] 42 First oil component
[0157] 43 Second oil component
[0158] 44 drive unit
[0159] 45 oil temperature sensor
[0160] 46 Expansion bodies
Claims
1. A method for processing rapeseed kernels (4), comprising the following steps: -The seeds (4) are dehulled, wherein, The kernels (4) are guided through the gap between the hulling rollers (5), and the husks are separated from the hulled kernel components (6) by sieving and / or air separation, such that the total amount of husks remaining in the hulled kernel components (6) does not exceed 4% by weight of the hulled kernel components (6). - Cold-pressed rapeseed oil (25) is obtained from the hulled seed component (6). -The water content of the hulled grain component is 4%-7% by weight. -In this process, the temperature of the cake produced by pressing (9) is limited to 70°C, and - Wherein, the first residual oil content is reduced to 18%-28% by weight of the dry weight of the pressed cake. Its features are, - Pressurized steam (30) is supplied to the pressed cake (9) and the pressed cake (9) is then expanded into an expanded body, wherein the steam is metered so that the pressed cake (9) is temporarily heated to over 100°C under the action of the steam (30), and the expanded body has a temperature of 80°C to 95°C after expansion. - The expanded body is extracted using an organic solvent, wherein the second residual oil content is reduced to 2% by weight or less of the dry weight of the expanded body, and - After expansion, a portion of the cake (9) is returned and mixed with a low-husk seed component (6) before pressing to increase friction during pressing, and then pressed again, wherein the returned portion of the cake is a portion of the expanded body formed by expansion. Specifically, the portion of the pressed cake (9) that is transported back after expansion is separated from the expanded body before and / or after extraction. The portion of the pressed cake (9) that is transported back after expansion is cooled to a temperature in the range of 20 to 35°C or 25 to 30°C before being pressed again.
2. The method according to claim 1, characterized in that, The portion of the pressed cake (9) that is transported back after expansion is separated before and / or after extraction by sieving smaller particles from the expanded body and optionally by sieving particulate components with a maximum particle size of 4 to 6 mm from the expanded body.
3. The method according to claim 1 or 2, characterized in that, The portion of the pressed cake (9) that is returned after expansion is a total of 5%-20% of the weight of the pressed cake (9).
4. The method according to claim 1 or 2, characterized in that, The hulled grain component (6) is pressed either without heat input or with heat output.
5. The method according to claim 1 or 2, characterized in that, The husk-rich grain component (31) is separated into a further husk-less grain component (10) and a husk component (11) by flotation (33) in water, wherein the further husk-less grain component (10) is optionally added to the husk-less grain component (6) before the pressurized steam (30) is delivered.
6. The method according to claim 1 or 2, characterized in that, The hulled kernel component (6) is rolled into flakes with a moisture content of 5%-8% by weight of the dry weight of the hulled kernel component before pressing, wherein the flakes are optionally... - Rolled to a sheet thickness of 0.1 to 0.8 mm, and - Maintain a sheet temperature of no more than 45°C.
7. The method according to claim 1 or 2, characterized in that, The cold-pressed rapeseed oil (25) is collected as a first oil component and a second oil component, wherein the first oil component is heated to a temperature not exceeding a limit during pressing, and the second oil component is heated to a temperature exceeding the limit during pressing, wherein the limit temperature is between 40 and 50°C.
8. The method according to claim 7, characterized in that, The fractional components are pressed by a screw extruder (8) having an extrusion screw (37) rotating about a horizontal axis of rotation (38) and a screen cover (39) surrounding the extrusion screw (37), wherein a weir (41) extending transversely to the axis of rotation (38) moves continuously in the direction of the axis of rotation (38) in an oil collection tank (40) arranged below the screen cover (39) so as to separate the first oil component (42) and the second oil component (43) of the cold-pressed rapeseed oil (25) in the oil collection tank (40) from each other.
9. The method according to claim 8, characterized in that, The weir gate moves in the direction of the rotation axis (38) according to the signal of at least one oil temperature sensor (45) arranged on the weir gate.
10. The method according to claim 1 or 2, characterized in that, The cake (9) is crushed before the pressurized steam (30) is delivered.
11. The method according to claim 1 or 2, characterized in that, The expanded body is extracted using the organic solvent to reduce the second residual oil content to 0.3%-1.3% by weight of the dry mass of the expanded body.
12. The method according to claim 1 or 2, characterized in that, The expanded body is extracted using the organic solvent to reduce the second residual oil content to 2% by weight or less of the dry weight of the expanded body, wherein the organic solvent is hexane or at least 95% ethanol.
13. The method according to claim 1 or 2, characterized in that, The solvent-swellable body is dried or subjected to solvent replacement to obtain its porous structure, wherein at least one replacement solvent is used, selected from pure ethanol and water-ethanol-azeotrope.
14. The method according to claim 1 or 2, characterized in that, The expanded body extracted with the organic solvent is then extracted with an aqueous alcohol solution to obtain a purified rapeseed protein concentrate (29), wherein the aqueous alcohol solution has 70%-96% or 80%-90% by volume of ethanol.
15. The method according to claim 14, characterized in that, The expanded body is ground into a suspension with an aqueous alcohol solution and extracted in a convection.
16. The method according to claim 14, characterized in that, The aqueous alcohol solution is at least 95% ethanol.
17. The method according to claim 14, characterized in that, The purified rapeseed protein concentrate (29) is dried by baking, rapid drying or vacuum drying.
18. An apparatus (1) for carrying out a method for processing rapeseed kernels (4) according to any one of the preceding claims, comprising: - A dehulling roller (5) that forms the roller gap and is used to dehull the grains (4); - A separation device connected downstream of the roller gap, the separation device having at least one sieve or air separator for separating the low-hulled grain component (6) from the high-hulled grain component (31); - A flaking roller (7) for crushing the hulled grain component (6) into flakes, - A screw press (8) for pressing cold-pressed rapeseed oil (25) from the sheet, wherein, The screw extruder (8) outputs a pressed cake (9); and - A return device (34) configured to return a portion of the pressed cake to the screw extruder (8). Its features are, An expansion device (14) is connected downstream of the screw extruder (8). This expansion device is used to deliver pressurized steam (30) to the cake (9) and then expand the cake (9) into an expanded body. An extraction device (15) is connected downstream of the expansion device, the extraction device being configured to extract the expanded body using an organic solvent. The return device (34) is configured to return a portion of the cake (9) after the expansion device (14) to increase friction in the screw extruder (8), wherein the returned portion of the cake is a portion of the expanded body formed by expansion, wherein the return device (34) has a cooling device (35) configured to cool a portion of the cake (9).
19. The apparatus (1) according to claim 18, characterized in that, The return device (34) is configured to separate a portion of the pressed cake (9) before and / or after extraction in the extraction device (15) by means of the organic solvent, by sieving the particulate components having a maximum particle size in the range of 4 to 6 mm from the expanded body.
20. The apparatus (1) according to claim 18 or 19, characterized in that, The screw extruder (8) has an extrusion screw (37) that rotates about a horizontal axis of rotation (38) and a screen cover (39), wherein a weir (41) extending transversely to the axis of rotation (38) is movable in the direction of the axis of rotation (38) in an oil collection tank (40) arranged below the screen cover (39), the weir separating the first oil component (42) of the cold-pressed rapeseed oil (25) in the oil collection tank (40) from the second oil component (43) that is pressed laterally.
21. The apparatus (1) according to claim 20, characterized in that, A drive device (44) is provided, which causes the weir gate (41) to move in the direction of the rotation axis (38) according to the signal of at least one oil temperature sensor (45) arranged on the weir gate (41).
22. The apparatus (1) according to claim 18 or 19, characterized in that, A flotation cell is provided, and the flotation cell is configured to separate the shell-rich grain component (31) into a further shell-less grain component (10) and a shell component (11) by flotation (33) in water, wherein the flotation cell optionally has a compressed air inlet and / or a stirrer to be introduced into or near its bottom.