Method for conditioning plant seeds for comminution, particularly for influencing the elasticity of the plant seeds, and plant for comminution of plant seeds

Description

[0001] The present invention relates to a method for conditioning plant seeds for comminution and for improving the moisture content of the plant seeds compared to untreated, unconditioned plant seeds.

[0002] The present invention further relates to a plant for comminuting plant seeds, comprising: a conditioning plant for conditioning the plant seeds for comminution, a comminution device for comminution of the conditioned plant seeds, and a separating device for separating different fractions of the comminuted plant seeds.

[0003] For example, to produce flour, the endosperm of a grain must be separated from the bran (seed coat, aleurone layer and germ).

[0004] In order to separate the shell from the hard kernel, the grains are conditioned by moistening (wetting) the shell so that it becomes tougher and can be separated from the kernel in as few fragments as possible.

[0005] The following section will examine the processing of grain, using plant seeds as an example. Wheat milling plays a crucial role, as 700 to 750 million tons of wheat must be processed annually worldwide.

[0006] From a wheat miller's perspective, the grain consists of the endosperm, the germ, and the surrounding bran layer. Biologically, the structure is more complex. The bran consists of many layers, which, from a developmental perspective, are intended to prevent access to the endosperm by harmful organisms. The seed coat (testa), in particular, is hydrophobic, thus also preventing water penetration. Beneath the bran lies the aleurone layer, which is connected to the endosperm. The endosperm cells develop in the aleurone layer. Nevertheless, from a milling perspective, the aleurone layer is considered part of the bran. Although it is rich in proteins, due to its structure, these do not make a positive contribution to the baking properties of a flour. Furthermore, it contains many minerals, which would lead to an undesirable increase in the mineral content of the flour.In many countries, including Germany, flours are classified into different types based on their mineral content. The miller generally aims for a high yield of flours with low mineral content because they are easier to market thanks to their higher baking quality and lighter color.

[0007] The separation of the bran is improved by superficial moistening (wetting or wetting), as this increases the toughness of the bran and thus prevents it from breaking down so easily into small pieces during the milling process, which are difficult to separate from the rest of the flour.

[0008] In addition, during flour production, it is also recommended to moisten the flour body, as this improves its milling properties and compensates for the expected moisture loss of the flour during the milling process. Wetting therefore also serves to adjust the water content of the flour and thus has a significant impact on the quality and cost-effectiveness of the final product.

[0009] For this complex task, a two-stage wetting process has generally been used. In the first step, approximately 2-5% water is sprayed onto the grain in a continuous vortex mixer and evenly distributed over the grain surface. The grain must then stand for 8-36 hours to allow the water to penetrate the grain. The actual standing time depends on the grain's properties. Large grains require longer than small ones, and hard grains require longer than soft ones.

[0010] The water does not penetrate across the entire grain, but initially only into cracks and crevices (capillaries) that extend deep into the endosperm [Münzing, K., 2013, "New findings on the wetting and mixing effect of milling wheat," Mühle Mischfutter 150(14), 246]. This process is completed after approximately 1 hour. Only then does the water gradually spread throughout the entire grain. Immediately before the actual milling, the shell is wetted to increase the toughness of the outer layers.

[0011] A mill must therefore maintain additional storage capacity on the order of a daily production, which requires considerable space and can be a limiting factor in the event of a desired expansion.

[0012] State-of-the-art includes mechanical processes designed to improve the distribution of water over the surface of the grains and its penetration into the grains. One such process, based on vibration, is described in DE 41 27 290 A1.

[0013] Also known, for example from WO 03 / 024242 A1, is the addition of salts or enzymes to the wetting water, which is intended to facilitate the removal of the bran.

[0014] Similar problems exist when conditioning other plant seeds for comminution. Plant seeds within the meaning of the present invention include, in particular, grains and pulses, i.e., cereals such as wheat, rye, barley, oats, triticale, corn, rice, and millet, as well as beans, peas, chickpeas, lentils, and soybeans, which belong to the legumes (pulses).

[0015] Comminution is the breaking up of solid materials under the action of mechanical forces. Comminution can be achieved, for example, by striking, splitting, rubbing, crushing, breaking, pressure, shearing, or impact. Hulling, i.e., the breaking open or removal of the seed coat, is also considered comminution within the meaning of this invention.

[0016] FR 2 685 223 A1 relates to a system for the continuous treatment of plant grains or seeds. The device comprises a storage device, a device for moistening the grains or seeds, and means for grinding the grains or seeds. Samples taken after grinding are fed to a measuring device to determine the moisture content and impurities. A computer is used to control and continuously monitor this system.

[0017] DE 10 2017 202 684 A1 relates to a method and a device for treating nuts to improve peeling properties. The shell of the nuts is softened by applying an electric field.

[0018] DE 735 937 C describes a process for facilitating the hulling or milling of grain. For this purpose, grain kernels, whose hulls contain more moisture than their kernels, are exposed to high-frequency alternating electrical fields. The high-frequency fields generate heat both within the kernel and within the hull. The moisture expands due to the heating and is pushed outward from the interior of the grain. This results in the dry kernel becoming harder and the moist hull becoming softer and more elastic, allowing the soft hull to be completely removed using conventional hulling devices.

[0019] In view of the above-mentioned problems, it is an object of the present invention to provide a method and a device for conditioning plant seeds which facilitates the comminution of the plant seeds and positively influences the behavior of the plant seeds during comminution.

[0020] The present invention solves this problem by a method for conditioning plant seeds for comminution, which is characterized in that the plant seeds are exposed to a non-thermal electric field.

[0021] The plant for comminuting plant seeds mentioned at the outset achieves this object in that the conditioning plant has a capacitor for generating a non-thermal electric field acting on the plant seeds to improve the moistening of the plant seeds compared to untreated, unconditioned plant seeds, wherein the conditioning plant further has a wetting device for moistening the plant seeds.

[0022] Surprisingly, it has been shown that the action of an electric field on plant seeds quickly and easily modifies their structure and texture, in particular their elasticity, so that the plant seeds can be crushed particularly well. The action of an electric field makes plant seeds, for example chickpeas, rice and soybeans, easier to hull; in other words, the shell can be removed surprisingly more easily, leaving almost no residue and thus better than with untreated plant seeds. For example, it has been surprisingly found that plant seeds, for example dry grains, have a more elastic seed coat after treatment with an electric field, which increases the toughness of the seed coat and improves crushing properties.Furthermore, it was surprisingly discovered that plant seeds exposed to an electric field are easier to wet and moisten with a liquid. Wetting or wettability refers to the behavior of the plant seed surface upon contact with liquids. The desired result is wetting as quickly and completely as possible, with the liquid spreading over the surface and adhering to it. Moistening refers to the distribution of the liquid throughout the entire plant seed, including the inner endosperm or endosperm. Wherever reference is made to an improvement, this refers to a comparison of the plant seeds conditioned according to the invention with correspondingly unconditioned plant seeds that were not exposed to an electric field.

[0023] The elasticity of a plant seed can be determined, for example, using a texture analyzer based on the maximum compression force. With such a machine, the plant seed can be compressed at a constant speed of, for example, 1 millimeter per second, and a force-displacement curve can be recorded. For compression, an aluminum cylinder with a diameter of 15 millimeters can be used, under which the seed is placed with its seed fold facing down. The texture of a plant seed can be determined, for example, using internationally recognized methods such as AACCI method 55-30.01. The texture of a wheat grain, which has important effects on milling quality and on parameters such as damaged starch, water absorption, and gas production, is determined by determining the relative hardness of all wheat varieties by determining the particle size index through milling and sieving.The data obtained during sieving is converted into a relative hardness using a table. The international method AACCI 55-31.01 can also be used to determine the texture of a wheat kernel by industrially measuring the force required to crush wheat kernels. The Single Kernel Characterization System instrument is calibrated to calculate the kernel texture using AACC Method 39-70.02 (near-infrared method) or a modification of Method 55-30.01 using a cyclone sample mill (impeller type). This method is applicable, for example, to all wheat varieties and hullless barley. Improved wettability or moisture penetration is indicated, for example, by either more liquid wetting the plant husk or more liquid adhering to the husk.penetrates the endosperm and is bound in the plant seed, or that a comparable amount of liquid in the conditioned plant seeds moistens the seed coat or penetrates the endosperm more quickly.

[0024] The invention can be further improved with the following further developments and advantageous embodiments, each of which is advantageous in itself and can be combined with one another as desired.

[0025] By exposing plant seeds to an electric field, the plant seeds can be electroporated, meaning the cell membrane becomes temporarily (reversibly) or permanently (irreversibly) permeable. The applied electric field can also cause controlled cell disruption, in which the degree of cell disruption is set to a predetermined value. The applied electric field is a non-thermal electric field, with the upper energy limit being such that essentially no heating of the plant seeds occurs in the sense of ohmic heating.

[0026] When treating with or applying the electric field, an energy input of at least 1 kJ / kg can be applied to the plant seeds. An energy input of this magnitude is well suited to modifying the texture and structure of the seeds and thus improving their elasticity and wettability / moisture penetration. To optimize the energy input and avoid energetically unnecessary overtreatment of the plant seeds, the energy input into the plant seeds can be between 1 kJ / kg and 20 kJ / kg, preferably between 8 kJ / kg and 12 kJ / kg.

[0027] It has also been shown to be beneficial if the plant seeds are exposed to an electric field of 0.3 kV / cm to 10 kV / cm, preferably 2 kV / cm to 4 kV / cm. Such field strengths can be achieved with commercially available industrial capacitors and prevent unwanted thermal effects that could lead to unintended product changes.

[0028] The plant seeds can be conditioned particularly effectively using electrical pulses, whereby the plant seeds are exposed to a pulsed electric field. For this purpose, the system according to the invention can, for example, provide a capacitor with at least two electrodes connected to a pulse generator as a voltage source. The capacitor and electrodes can represent parts of an electroporator for treating the plant seeds with a pulsed electric field. The electric field, in particular the electrical pulses, can be generated both by direct contact of the capacitor or its electrodes with the plant seeds, or via fluids, whereby the plant seeds are fully or partially immersed in the fluids.Various electrode shapes can be used, such as plate, ring, grid, hollow, or flow-through electrodes, which can be arranged in a variety of ways, for example, parallel, coaxial, collinear, conical, or as an annular gap. A high-voltage pulse generator, such as a Marx generator, can be used as a pulse generator. This generates electric fields in the form of short pulses in the microsecond to millisecond range at a high voltage in the kV range. Such high-voltage pulses cause electroporation in the plant seeds to be conditioned, which results in particular in the permeabilization of the cell membrane and beneficially influences the structure and texture of the plant seeds in a particularly simple and non-thermal manner.

[0029] In order to optimize time and energy, the plant seeds can be softened with at least 10 electrical pulses, preferably 10 to 200 electrical pulses and preferably 30 to 50 electrical pulses.

[0030] According to a further embodiment, the elasticity of the plant seeds can be improved during conditioning compared to unconditioned plant seeds. The elasticity can in particular be adjusted to a specific elasticity range that is geared to the desired particle size or the degree of grinding or milling. For example, the particle size is that finely ground flour has a particle size of < 180 µm, so-called semolina has a particle size of 300 to 1000 µm, and grit has a particle size of more than 1000 µm. The degree of fineness between flour and semolina is referred to as dust and has a particle size of 180 to 300 µm. The degree of grinding describes how much flour can be produced from 100 kg of grain, particularly in grain processing in the mill.In Germany, for example, the degree of milling for wheat can be described by the corresponding flour designations, such as the German DIN designations Type 405, Type 550, Type 1050, or wholemeal. Corresponding classifications also exist for bran or rye flour.

[0031] Particularly preferably, the elasticity of the seed coat and / or the elasticity of the seed kernel, in particular of the endosperm, can be modified during conditioning. The plant kernel is understood to mean everything within the seed coat, including the endosperm and the embryo or germ. By means of the conditioning according to the invention, the elasticity of the seed coat can be adjusted such that the coat can be removed from the seed kernel easily and with almost no residue during comminution. At the same time, the elasticity of the seed kernel can also be adjusted such that the hulled seed kernel is prepared for further processing, e.g. further comminution or preservation in its entirety. For example, the elasticity of grains can be adjusted such that the elasticity of the bran improves and the elasticity of the endosperm remains unchanged and brittle.This has the advantage that the more elastic and therefore tougher bran breaks down into fewer fragments when crushed than the more brittle kernel, making it easier to separate the bran from the ground flour body.

[0032] According to a further embodiment, a moistening liquid can be added to the plant seeds before or during their exposure to the electric field. For this purpose, the conditioning system of the system according to the invention can, for example, comprise a wetting device for moistening the plant seeds, for example in the form of spray nozzles, via which the plant seeds are exposed to a moistening liquid on their surface. A moistening liquid such as water can be added to the plant seeds, for example, in a range of 0.5 to 20%, preferably 2 to 5%.

[0033] The percentage of wetting water or moistening fluid refers to the unwetted grain. So, if 1,000 kg of wheat are to be wetted with 2%, 20 kg of water are required. However, the total mass is naturally taken into account when calculating the required water quantity. The reference value is the desired milling moisture content, taking into account the initial moisture content. The formula for this is: % Wasserzugabe = 100 * Zielfeuchte - Ausgangsfeuchte / 100 - Zielfeuchte

[0034] Example: 14% initial moisture content must be moistened with 2.99% to achieve 16.5% final moisture content.

[0035] It has also been shown that conditioning using electric fields leads to beneficial wetting and moistening even with a relatively small amount of wetting liquid. For example, the mass ratio of wetting liquid to plant seeds during treatment using an electric field can be between 1:1 and 20:1, preferably between 1:1 and 10:1. The mass ratio is influenced, on the one hand, by the desired water absorption and, on the other hand, by the design of the electroporation and product conveying device. If a higher water addition is necessary for conveying through the treatment device or to compensate for any voids during treatment, a separation step can be carried out afterwards to remove excess water.

[0036] Conditioning the plant seeds with an electric field, especially when electroporation is performed, facilitates the adhesion of the moistening fluid to the seed coat, which significantly improves wetting. Furthermore, the conditioning according to the invention accelerates the penetration of the fluid to the inner endosperm, which significantly reduces wetting and the required standing times, which are typically 8 to 36 hours for grains. Conditioning using electric fields thus not only ensures a positive texture change in the plant seeds, but also improves wetting and moistening, thus shortening standing times.

[0037] The standing time is the time required for water to penetrate into the interior of the plant seed, for example, the grain. For this purpose, the system according to the invention comprises at least one standing cell as part of its conditioning system. The electrodes of the capacitor can be part of the standing cell or upstream of the standing cell, for example, directly upstream of or in a conveyor or dosing device for transporting the plant seeds into the standing cell. The wetting device of the conditioning system can also be part of the standing cell or upstream of the electrodes or integrated into the electroporator.

[0038] According to a further embodiment, the plant seeds can be exposed to a predetermined pressure and / or a predetermined temperature. The exposure to a predetermined temperature or a predetermined pressure can take place during the exposure to an electric field, or also downstream of the electric field, for example during the standing time, during which plant seeds conditioned with the electric field remain in a standing cell. The pressure or the temperature can, for example, be selected such that certain enzymes that advantageously influence the texture of the plant seeds or accelerate the action of the wetting liquid are close to the temperature optimum (the temperature with the highest enzyme activity). The conditioning system can, for example, have a temperature controller and / or a pressure controller for this purpose. With the help of these controllers, for example, the temperature orthe pressure in the electroporator and / or in the standstill cell is set and maintained at a predetermined setpoint.

[0039] According to a further embodiment, enzymes can act on components of the plant seeds within the framework of the conditioning process according to the invention. It has been shown that, for example, endogenous enzymes are released through electroporation and, if necessary, can be activated after activation by setting a specific temperature, a specific pressure, or simply a specific standing time. The desired enzyme activity could also be positively influenced by the choice of the pH value or the polarity of the wetting liquid. It is also possible to add enzymes to the plant seeds during conditioning, for example, during or after exposure to an electric field. It is conceivable, for example, to mix the enzymes with the wetting liquid, which is then added to the plant seeds.Hemicellulytic enzymes, in particular, can significantly reduce the required standstill time and improve the separation of endosperm and seed coat, or of bran and endosperm, thus increasing flour yield. Examples of enzymes include hemicellulases, cellulases, glucanases, laccases, proteases, amylases, and other enzymes that act on plant seed components, especially grain components.

[0040] The invention will be explained in more detail below using advantageous embodiments with reference to the drawings and the following test examples. The advantageous further developments and embodiments presented are independent of one another and can be combined with one another as required in the specific application.

[0041] They show: Fig. 1: a schematic representation of an exemplary embodiment of a plant for crushing plant seeds; Fig. 2: photos of wheat grains after crushing in a texture analyzer: a dry control, a control after soaking, and a sample after treatment with an electric field and soaking; Fig. 3: an illustration illustrating the characterization of the examination positions within the framework of an EDX (energy dispersive X-ray spectroscopy) analysis for determining the distribution of oxygen in wheat grains; Fig. 4: a graph illustrating the moisture penetration of untreated control samples immediately at the beginning of moisture penetration; Fig. 5: a graph illustrating the moisture penetration of grain samples conditioned using electric fields immediately at the beginning of moisture penetration; Fig.Fig. 6: a graph illustrating the moisture penetration of control samples conditioned by means of electric fields after 10 hours of moisture penetration; Fig. 7: a graph illustrating the moisture penetration of untreated grain samples after 24 hours of moisture penetration; and Fig. 8: a diagram illustrating the improved comminution of plant seeds treated according to the invention.

[0042] In the following, an exemplary method for conditioning plant seeds and an exemplary embodiment of a plant for comminuting plant seeds according to the present invention are described with reference to the Fig. 1 explained.

[0043] The Fig. 1The system 1 shown comprises a conditioning system 2 for conditioning plant seeds 3, a crushing device 4 for crushing the conditioned plant seeds, and a separating device 5 for separating different fractions of the crushed plant seeds. The plant seeds 3 are in the Fig. 1 shown schematically as circles.

[0044] The conditioning system 2 comprises a capacitor 6 for generating an electric field.

[0045] In the embodiment shown, the conditioning system comprises a stand-off cell 7 and a dosing device 8, with the aid of which plant seeds 3 are introduced into the stand-off cell 7, which is symbolized by arrows.

[0046] In the embodiment shown, the capacitor 6 comprises two electrodes 9, which are connected to a voltage source 11 via power lines 10. Two capacitors 6 are shown by way of example. The electrodes 9 of one capacitor are arranged in the stand-off cell 7 and can generate an electric field in the stand-off cell 7. The other capacitor 6 is provided in the region of the dosing device 8 and is designed such that plant seeds 3 can be exposed to an electric field when passing through the dosing device 8. Of course, two capacitors do not necessarily have to be provided; it would just as well be possible to provide the capacitor only in the stand-off cell 7 or only in the region of the dosing device 8. For the sake of clarity, only one power line 10 to one of the two electrodes 9 of a capacitor 10 has been drawn.

[0047] In the embodiment shown, the electrodes 9 of a capacitor 6 are arranged parallel to each other, creating a homogeneous electric field for uniform sample treatment. However, other variants of the electrode arrangement are also conceivable, for example, a coaxial or collinear arrangement.

[0048] A pulse generator, for example a high-voltage pulse generator such as a Marx generator, can be used as the voltage source 11, with which electrical pulses of a high voltage in the kilovolt range and a short duration in the micro- to millisecond range can be generated.

[0049] To condition the plant seeds 3, for example, at least 10 electrical pulses, preferably 10 to 200, and particularly preferably 30 to 50 electrical pulses, can be introduced. Applying an electric field of 0.3 kV / cm to 10 kV / cm achieves an energy input of more than 1 kJ / kg, for example, from 1 kJ / kg to 20 kJ / kg, preferably from 8 kJ / kg to 12 kJ / kg, into the plant seeds 3.

[0050] This allows controlled cell disruption of the plant seeds 3 to be achieved, for example by electroporating the plant seeds 3 using the pulsed electric field.

[0051] The voltage source 11 is connected via a control line 12 to a central control unit 13, which controls the voltage source.

[0052] In the shown embodiment of the Fig. 1The conditioning system 8 further comprises a wetting device 14 for moistening the plant seeds 3. The wetting device 14 for moistening the plant seeds 3 is, for example, configured in the standing cell 7. It comprises a storage container 15, which is connected via a supply line 16 to a spray device 17 arranged in the standing cell 7. The storage container 15 can contain a moistening liquid 18, which can be transported via the supply line 16 to the spray device 17 and distributed there inside the standing cell 7. The moistening liquid 18 can be added to the plant seeds 3 in this way. The addition of the moistening liquid 18 can also be controlled via the central control unit 13, which is connected to the wetting device 14 via a further control line 12.

[0053] In the illustrated embodiment, a temperature and / or pressure regulator 19 is further provided in the holding cell 7. The regulator 19 may, for example, comprise a thermostat 20 arranged in the holding cell 7, with the aid of which the temperature in the holding cell 7 can be regulated to a predetermined value. The regulation can be effected via the central control unit 13, which in the exemplary embodiment is connected to the thermostat 20 via a further control line 12. Even if this is not the case in the Fig. 1 Although not explicitly shown, a pressure regulator may also be provided in the stand cell 7 to set a predetermined pressure inside the stand cell 7. A pH regulator for regulating the pH value of the mixture of plant seeds 3 and moistening liquid 18 would also be conceivable.

[0054] The exemplary conditioning system 2 from Fig. 1enables the method according to the invention for conditioning plant seeds to be carried out by exposing the plant seeds 3 to an electric field. The plant seeds can be electroporated by means of an electric field and a defined cell disruption can be carried out. During the conditioning, the elasticity of the plant seeds 3 can be improved and adjusted to a predetermined range. Thus, the plant seeds, for example grains, i.e. cereals such as wheat, can be prepared for a subsequent comminution process, for example a milling process, which has a positive influence on the milling behavior. The treatment by means of an electric field facilitates and accelerates, for example, the wetting and moistening of the plant seeds 3 with the moistening liquid 18 and enables a targeted influencing of the elasticity of the plant seeds.This improves, as will be shown below using experimental examples, the breaking behavior of the plant seeds and reduces flour loss by improving the separation of the flour fraction from the bran.

[0055] In one embodiment, enzymes can be added to the wetting liquid to accelerate wetting or moistening or otherwise positively influence the texture or structure of the plant seed 3 for subsequent comminution. For example, hemicellulotic enzymes can be used, such as hemicellulases, cellulases, glucanases, laccases, proteases, and amylases, which further reduce the required standing time in the standing cell 7 and improve the separation of the seed coat from the seed kernel, for example, the bran from the endosperm in cereals, thus optimizing the milling yield. Hemicellulases include pentosanases, such as arabinases and xylanases (such as endo-1-4-β-xylanase, endo-1-3-β-xylanase, exo-1-4-β-xylanase, exo-1-3-β-xylanase, or arabinofuranosidase, ferulic acid esterase, coumaric acid esterase, or acetic acid esterase). Other possible hemicellulases are hesosanases, such as β-glucanase, galactase, or mannase.

[0056] In addition to the addition of enzymes via the moistening liquid 18, enzymes can also act on components of the plant seeds 3 in other ways. For example, endogenous enzymes can be released by means of the electric fields, particularly during electroporation, which, after a sufficiently long standing time or by setting a temperature, pressure, or pH value optimal for enzyme activity, are subsequently activated via temperature and / or pressure control.

[0057] By means of all these measures, the structure and texture of the plant seeds 3 can be conditioned and adapted to the desired crushing properties of the plant seeds 3. For example, the elasticity of the seed coat and / or the elasticity of the seed grain can be very precisely adjusted in this way.

[0058] After conditioning, the conditioned plant seeds 3 are fed from the stand-off cell 7 to the comminution device 4 via a transfer line 21. In the comminution device 4, the conditioned plant seeds are comminuted, for which, for example, pressure comminution, impact comminution, friction comminution, cutting comminution, and / or impact comminution, or dehulling can be used. Comminution machines include, for example, crushers, mills, dehulling machines, or other mechanical comminutors, as well as steam dehullers.

[0059] The crushed plant seeds 3 are transferred from the crushing device 4 to the separating device 5 via a transfer device 22. In the separating device 5, different fractions of the crushed plant seeds are separated from one another. For example, the hull of hulled plant seeds, such as hulled chickpeas, rice, and soybeans, can be separated. Possible processes for separating the fractions include sieving or sifting. Grain mills often use sifters to classify solids according to defined criteria such as particle size, density, inertia, and suspension or stratification behavior, thus allowing different fractions (i.e., fractions with different particle properties) to be separated from one another.

[0060] The desired fraction of plant seeds obtained by comminution is finally discharged from the separation device via outlet 23. The fraction that does not yet have the desired properties can be returned to the comminution device 4 via a return line, according to the exemplary embodiment, and comminuted again. Of course, instead of being returned, this fraction can also be transferred to a further, second comminution device (not shown).

[0061] The product process of comminution and separation is carried out in grain mills by grinding in roller mills and subsequent sifting. A pass through a comminution device 4 and subsequent separation device 5 is referred to as a passage. In the exemplary embodiment of the Fig. 1Thus, an exemplary grinding passage 25 is shown with a comminution step carried out in a comminution device 4 and subsequent separation of different fractions in a separation device 5.

[0062] In the following, exemplary embodiments of the method according to the invention and the advantages achieved thereby are presented on the basis of some concrete test results.

[0063] For the treatment of grain with pulsed electric fields (PEF), the grains were covered with water. A ratio of 100 g (grain): 800 g (water) was chosen. However, any other ratio could have been chosen to ensure complete wetting of the grain. The PEF treatment was carried out in a batch system with a treatment cell with a capacity of 900 ml. The applied field strength was 3 kV / cm, and the energy input was 10 kJ / kg. The grains were then transferred to a sieve and separated from the treatment water. Immediately after the PEF treatment (in which the grains were immersed in water for only 2 minutes, significantly less than the usual hour), approximately 18 g of water remained on the grains as surface wetting.

[0064] After treatment, the texture properties were determined using a texture analyzer with regard to compression and cutting force. After PEF treatment and soaking, an increase in the maximum compression force from 34.94 kg for untreated samples to 42.96 kg was observed. The fracture behavior of the PEF-treated samples was thus advantageously more elastic and less brittle than that of the untreated control samples. The seed coat of PEF-treated grains thus breaks down into fewer pieces, making the endosperm easier to separate than in the dry or the soaked, but not PEF-treated sample (see Fig. 2 ).

[0065] The analysis of water distribution in the grain was performed immediately after treatment, after 10 and 30 minutes, and after 1, 2, 4, 10, and 24 hours. A control sample was analyzed in parallel using the same method. Using EDX analysis, the distribution of elements in the grains was determined, and water penetration was characterized by an increase in the oxygen content. The test positions are shown in Fig. 3 shown.

[0066] The wheat grains treated with PEF showed the same Figs. 4 to 7 The PEF-treated grains showed better water distribution than the untreated samples right from the start of the moistening process, as indicated by the line above the mean (MW) plus standard deviation (S). After just 10 hours, the PEF-treated grains had optimal, uniform moisture penetration of the endosperm for milling, while this was only achieved after 24 hours in the untreated samples.

[0067] The resulting loosening of the endosperm structure and loosening of the bond between the aleurone layer and the endosperm made it possible to shorten the standing time while maintaining a comparable flour yield.

[0068] A possible embodiment of the invention is illustrated below using an experimental example.

[0069] For the experiments, wheat (Triticum aestivum L., winter soft wheat, variety Butaro, August 2017) from a single batch was placed in 400 g portions into the treatment tank of a discontinuous PEF system. Subsequently, 300 mL of tap water (possibly with the enzyme xylanase dissolved in it, 10–100 ppm, calculated on the grain) was poured over the water, and the tank was treated with PEF for 20 s. 31 pulses of 30 kV and 450 J each were delivered to the grains; the specific energy input per batch was 20 kJ / kg. After a total contact time with the water of 60 s, the water was removed by centrifugation. The moisture content of the grains after centrifugation was between 15.2 and 16.4%. Eight trials were carried out for each setting to obtain a sufficient amount of grain for grinding on a laboratory mill (Bühler MLU).

[0070] The flour yield (extraction rate) was set to an ash value of 0.63. The ash content is a crucial quality characteristic and correlates with the extraction rate. The extraction rate is determined from the ratio of the flour weight to the total weight as a percentage. This is an index of the efficiency of the milling process by comparing the weight of the total output with the initial weight. In the tests, the weight percentage of the passage flours and the bran milled flours were added together and calculated in relation to the weight of the wheat.

[0071] Formula for the extraction rate: E = EP + EK EG ∗ 100 E = extraction rate [%]; EP = extraction of passage flour [g]; EK = extraction of bran flour [g]; EG = total weight [g]

[0072] In addition, the extraction rate with adjusted ash content was included as a key parameter. This was calculated using a formula that fixes the ash percentage, as this is a quality characteristic and influences the extraction rate.

[0073] Formula for the adjusted extraction rate: EP ∗ AP + AEK ∗ AK = EG ∗ AG EG = EP + AEK AEK = EP ∗ AG − AP AK − AG AE = AEK + EP EG EP = Extraction of passage meal [g] AEK = Adjusted extraction of bran mill [g] EG = Total weight [g] AP = Ash of passage meal [% i. dry matter] AK = Ash of bran mill [% i. dry matter] AG = Ash target percentage value AE = Adjusted extraction value

[0074] Fig. 8 shows that conditioning with an electric field, both alone and in combination with the enzyme xylanase, surprisingly increases flour yield. Compared to the untreated reference, the yield increase was 1.4% with PEF and 1.8% with the combination of PEF and enzyme. Reference symbol

[0075] 1System 2Conditioning system 3Plant seeds 4Crushing device 5Separation device 6Condenser 7Standing cell 8Dosing device 9Electrodes 10Energy line 11Voltage source 12Control line 13Control unit 14Wetting device 15Storage container 16Feed line 17Spray device 18Humidification fluid 19Temperature and / or pressure regulator 20Thermostat 21Transfer line 22Transfer 23Output 24Return line 25Passage

Claims

1. Method for conditioning plant seeds (3) for disintegrating and for improving the wettability of the plant seeds (3) compared to untreated, non-conditioned plant seeds, characterized in that the plant seeds (3) are exposed to a non-thermally acting electrical field.

2. Method according to claim 1, wherein the plant seeds (3) are electroporated by means of the electrical field.

3. Method according to claim 1 or 2, wherein in the treatment with the electrical field, an energy input of 1 kJ / kg to 20 kJ / kg, preferably of 8 kJ / kg to 12 kJ / kg, into the plant seeds (3) is accomplished.

4. Method according to one of claims 1 to 3, wherein the plant seeds (3) are exposed to an electrical field strength of 0.3 kV / cm to 10 kV / cm, preferably of 2 kV / cm to 4 kV / cm.

5. Method according to one of claims 1 to 4, wherein the plant seeds (3) are exposed to a pulsed electrical field.

6. Method according to one of claims 1 to 5, wherein the elasticity of the plant seeds (3) is improved during conditioning compared to non-conditioned plant seeds.

7. Method according to claim 6, wherein the elasticity of the seed coat and / or the elasticity of the seed kernel, in particular the endosperm, is modified during conditioning.

8. Method according to one of claims 1 to 7, wherein a moistening liquid (18) is added to the plant seeds (3) before or while they are exposed to the electrical field.

9. Method according to one of claims 1 to 8, wherein the plant seeds (3) are exposed to a predetermined pressure and / or a predetermined temperature.

10. Method according to one of claims 1 to 9, wherein enzymes act on components of the plant seeds (3).

11. Method according to claim 10, wherein the enzymes are selected from the group of hemicellulases, cellulases, glucanases, laccases, proteases und amylases.

12. System (1) for disintegration of plant seeds (3), comprising a conditioning system (2) for conditioning the plant seeds (3), a disintegration device (4) for disintegration of the conditioned plant seeds (3), and a separating device (5) for separating different fractions of the disintegrated plant seeds, wherein the conditioning system (2) has a capacitor (6) for generating a non-thermally acting electrical field that acts on the plant seeds (3) for improving the wettability of the plant seeds (3) compared to untreated, non-conditioned plant seeds, and wherein the conditioning system (2) has a wetting device (14) for moistening the plant seeds (3).

13. System (1) according to claim 12, wherein the conditioning system (2) further has a tempering cell (7).

14. System (1) according to claim 12 or 13, wherein the conditioning system (2) has a temperature and / or pressure controller (19).

15. System (1) according to one of claims 12 to 14, wherein the capacitor (6) comprises at least two electrodes (9) which are connected to a pulse generator as a voltage source (11).