METHOD FOR PRODUCEING ONE OR MORE PROTEIN PREPARATIONS AND OIL FRACTIONS FROM SUNFLOWER SEEDS

Description

Application area

[0001] The invention relates to a process for obtaining one or more protein preparations and oil fractions from sunflower seeds. The fractions obtained or formed from the seeds in this process can be used as food ingredients, animal feed, processing aids, energy carriers, or as feed additives or bedding in animal husbandry. State of the art

[0002] Against the backdrop of increasingly scarce agricultural land and resources, plant-based protein preparations are gaining in importance for human nutrition, technical applications and use in animal feed.

[0003] Pressing and extraction residues from the production of edible oil from sunflower and rapeseed seeds are a cost-effective source of food and feed proteins. These seeds are characterized by a hard shell with predominantly dark pigmentation and an oil-rich pulp. Separating the shells from these raw materials is possible, but particularly complex in the case of rapeseed.

[0004] The pressing and extraction residues from oil production are primarily used as animal feed today. However, their use is limited despite their high protein content. This is due, firstly, to a very high hull content in the residue, which exceeds 25% by mass and can even exceed 50% in some cases. Furthermore, the proportion of interfering substances is very high, especially the content of secondary plant compounds such as polyphenols, tannins, glucosinolates, and phytic acid. These components can total over 10% by mass in the residues and significantly impair the color, taste, and digestibility of the proteins. Press cakes and extraction residues from sunflower and rapeseed oil production are therefore unsuitable for the production of high-quality protein meals for food and feed and, due to the secondary plant compounds they contain, are only suitable for feeding certain animal species in small quantities.

[0005] Sunflower and rapeseed are processed using state-of-the-art technology with a focus on high oil yield. First, they are cleaned of impurities, partially conditioned (by setting a defined temperature and humidity), then mechanically pre-de-oiled by pressing (residual oil content maximum 10% by mass), and subsequently the remaining oil is extracted from the press cake using hexane. A so-called final pressing down to a residual oil content of approximately 5% by mass without subsequent extraction is also carried out, although the residual oil content in the press cake reduces the storage stability of the residues.

[0006] Currently, sunflower and rapeseed are predominantly pressed unhulled or partially hulled. With partial hulling, over 50% by mass of the hulls contained in the seeds remain in the raw material before oil extraction, which on average corresponds to a residual hull content before pressing of >12% by mass for sunflower seeds and >8% by mass for rapeseed. According to current technology, a higher hull content is considered necessary, particularly for pressing—that is, final pressing or pre-pressing as partial oil extraction—to facilitate oil drainage from the press and thus increase throughput.

[0007] For several years, there have been approaches to processing proteins from the residues of sunflower or rapeseed oil production into protein meals or concentrates, thus making them usable for food and high-quality feed applications. Several publications describe the production of protein concentrates from rapeseed and sunflower seeds. These protein concentrates are obtained through dry or wet processing (e.g., using solvents), with the protein remaining in the residue. However, the high proportion of undesirable components and the high crude fiber content limit the use of these residues as feed, so that a particular advantage compared to sunflower and rapeseed extraction meals is often not apparent. Most of these protein concentrates therefore have a limited range of applications and can only be used in low concentrations in feed.

[0008] German patent DE 24 21 270 A1 describes a process for producing a protein concentrate from rapeseed, in which a meat fraction, a fine fraction, and a hull fraction are obtained from rapeseed. Leslie AJ ​​et al., "Nutritive Value of Air-Classified Rapeseed Fractions," CAN. J. ANIM. SCI, Vol. 53, January 1, 1972, pages 153-156, XP055787914, disclose a process in which rapeseed is separated into three fractions by means of air classification and sieving: a hull fraction, a hull-free fraction, and a fraction containing both components.

[0009] EP 2 885 980 B1 describes, among other things, a process for obtaining sunflower protein as a protein-rich food or feed. The feed is produced using hulled sunflower seeds with a residual hull content of >5% by mass. The seeds are pressed to achieve an oil content of ≥8% to ≤18% by mass and a protein content of ≥30% to ≤45%, based on dry matter. The influence of a lower residual hull content on the digestibility of the proteins is not addressed. Furthermore, it can be assumed that the high crude fiber content and the high chlorogenic acid content of the product could severely limit its palatability and thus its usability as feed. However, the publication does not disclose whether this process allows for the complete utilization of all seed fractions.

[0010] WO 2010097238 A2 also describes a process for producing protein preparations from hulled sunflower seeds. In this process, the sunflower seeds are hulled to a residual hull content of ≤ 5% by mass, or hulled sunflower seeds with a residual hull content of ≤ 5% by mass are provided. The hulled sunflower seeds undergo partial mechanical de-oiling by pressing until the fat or oil content of the hulled sunflower seeds is between 10 and 35% by mass. After one or more extraction steps with at least one solvent, a defatted, protein-containing flour is obtained as a protein preparation. The protein preparation exhibits highly advantageous properties, both visually and functionally, which allow for direct use in the food or feed sector.The low temperatures achieved through pressing at under 80°C and desolventing at under 90°C ensure that good techno-functional properties are retained, a low degree of denaturation is maintained, and thus very good digestibility and bioavailability should be achieved. However, due to the low temperatures during the processing of the sunflower seeds (below 90°C), industrial use of this method results in very long residence times in the solvent-based process stages and high process costs.

[0011] EP 2163159 B1 describes a process for utilizing oilseed crops (e.g., rapeseed, sunflowers, flax, or camelina) in which oil is extracted and the remaining plant constituents obtained during oil extraction are at least partially removed, with proteins being at least partially recovered. The deproteinized plant constituents are then at least partially processed for energy recovery, particularly for generating electricity and / or usable heat. This enables a largely holistic utilization of the fractions in oilseeds, both as protein for food and feed applications and as an energy source from the protein-free, carbohydrate-rich fraction.

[0012] WO 2019 / 048695 A1 discloses a process for obtaining protein preparations and several oil fractions from sunflower seeds, in which a low-hull fraction is provided and defatted to a residual oil content of < 4 wt.%, thereby obtaining a protein preparation and at least one oil fraction.

[0013] The object of the present invention is to provide a method for obtaining one or more protein preparations and oil fractions from sunflower seeds, in which all fractions obtained during the processing of the sunflower seeds can be converted into ingredients of the highest possible quality for food, feed, energy or technical applications. Description of the invention

[0014] This problem is solved by the method according to claim 1. Advantageous embodiments and further developments of the method are the subject of the dependent claims or can be found in the following description and the exemplary embodiments.

[0015] In the process according to the invention, sunflower seeds are first hulled, and the kernels are then freed from the hulls and separated by sieving, screening, and sorting such that at least three fractions with the hull proportions specified below are obtained, or fractions of sunflower seeds with these hull contents are already provided. According to the invention, the process comprises the following steps.

[0016] The sunflower seeds A first fraction is separated or provided, the shell content of which is less than 1 wt%, advantageously less than 0.5 wt%, particularly advantageously less than 0.1 wt%, wherein the first fraction is further processed to a first protein preparation by at least partially separating the oil to a residual oil content of <3 wt%, advantageously less than 2 wt%, thereby obtaining one or more oil fractions, and a second fraction is obtained or provided, the shell content of which is higher than that of the first fraction, but at least more than 0.3 wt%, advantageously more than 1 wt%, particularly advantageously more than 5 wt% but less than 20 wt%, advantageously less than 10 wt%, wherein oil is separated from the second fraction, thereby obtaining one or more further oil fractions, and in an advantageous embodiment by at least partially separating the oil to a residual oil content of less than 10 wt%, advantageously less than 3 wt%.-% a second protein preparation is obtained, and a third fraction, hereinafter also referred to as the shell fraction, with a shell content greater than 60 wt%, advantageously greater than 80 wt% and less than 99 wt%, advantageously less than 90 wt%, is separated or provided.

[0017] Advantageously, further fractions are obtained or provided which also contain proteins from the kernels of sunflower seeds and from which oil and a protein-rich residue can be obtained, the protein content of which is higher than that of the shells.

[0018] Surprisingly, this process, by providing or forming multiple fractions with the specified shell contents, significantly reduces the energy required on average to produce one kilogram of peeled kernels. The specific energy consumption is compared to the energy required to produce or provide only one fraction, where this single fraction has the same total mass as two or more fractions according to the invention and contains, on average, the same proportion of shells. By separating several fractions with different shell contents, it is even possible in some cases to completely eliminate the need to process individual fractions multiple times through the peeling and sorting unit, since even a correspondingly higher shell content can be directly utilized, thus eliminating the need for further processing.

[0019] The fraction separation according to the invention allows all resulting fractions to be converted into ingredients for food, feed, energy, or technical applications. In particular, the provision or formation of the first fraction leads to a high-quality protein preparation for food.

[0020] Furthermore, this fractionation process demonstrates that it is possible to simultaneously obtain vegetable oils with different properties from a single input stream. With appropriate process control, particularly by reducing the shell content in one fraction to less than 0.1% by mass and, if necessary, in a second fraction to values ​​below 1% by mass, it is possible to use one or more oil fractions directly without further treatment (e.g., refining), while other fractions require further processing. The oils from the first, second, and potentially subsequent fractions differ considerably in their composition, as well as in their taste and color. The content of flavor-active secondary plant compounds, such as tannins, also differs significantly between oils from the first and second fractions.Thus, these oils can be used directly for different applications, after simple filtration or after further processing (e.g. refining or mixing with other fractions), in different markets for different applications.

[0021] For example, the oil extracted from the first fraction of sunflower seeds is characterized by the absence of cuticular waxes or only trace amounts, and by its mild, nutty flavor. In contrast, oils from the second fraction have higher wax content, a slightly bitter taste, and a slightly darker color. This fraction is therefore primarily used unrefined for technical applications or for human consumption only after complete refining, including winterization, degumming, deacidification, bleaching, and deodorization.

[0022] Thus, the fractionation of sunflower seeds according to the invention surprisingly reduces the proportion of oil that requires refining. This saves energy and the use of chemicals required for deacidification or deodorization of oils according to prior art. Furthermore, oil losses associated with each step of conventional oil refining are reduced. Based on the present invention, the process of producing vegetable oil can be made significantly more resource- and energy-efficient per kg of input material compared to prior art processes, and in particular, higher oil yields are achieved.

[0023] The fractionation process according to the invention makes it easy to produce or provide variable quantities of the individual fractions depending on market demand or raw material properties, so that the process also enables particularly efficient operation in terms of usability and thus resource utilization. Preliminary trials show that the first fraction should advantageously contain between 1 and 80% of the number of kernels fed into the overall process via the starting material; advantageously, the proportion is between 5 and 35%, and particularly advantageously between 15 and 25%. With this proportion of kernels in the highly purified first fraction, particularly simple and cost-effective operation is possible, and a significant proportion of the oil can be used untreated and does not need to be refined.

[0024] A protein preparation made from the first fraction of Sunflower seedsThe extracted material should be processed as gently as possible for use in order to maintain high functionality and good sensory properties.

[0025] The shell content in the kernel fraction should be <1 wt%, particularly advantageously <0.1 wt%, and in a preferred embodiment, the kernels are pressed or mechanically de-oiled to an oil content of >10 wt% to <30 wt%, preferably between 10 and 20 wt%, at a mean temperature of the first fraction during the pressing process below 80 °C, preferably below 60 °C. In a subsequent solvent treatment with an organic solvent, e.g., hexane, supercritical CO2, or ethanol, further oil reduction to a residual oil content of less than 3 wt%, preferably less than 2 wt%, is achieved.

[0026] The protein preparation obtained during this treatment consists of Sunflower seedsIt has the following properties: It has a protein content of less than 90 wt% based on the dry matter (DM), advantageously less than 80 wt%, particularly advantageously less than 70 wt%, has a brightness L*, determined according to CIE L*a*b* color measurement, of at least 70, advantageously >80, and exhibits at least water-binding, oil-binding, and emulsifying functionalities. The water-binding capacity of the preparation is >1 ml per gram DM, preferably >2 ml per gram DM. The oil-binding capacity is >0.5 ml / g DM, preferably >1 ml / g DM, and the emulsifying capacity is >300 ml / g DM, preferably >400 ml / g, particularly preferably >500 ml / g. The protein solubility in the preparation is above 25%, particularly preferably above 40%.

[0027] In the process according to the invention, it is also possible to produce, in addition to the first and second fractions, a further fraction that is also virtually shell-free, but which can be used for direct consumption rather than for the production of oil and protein. This fraction is advantageously formed from a very high proportion of visually appealing, unbroken kernels. This proportion is advantageously above 70% of the kernel mass, and particularly advantageously above 90% of the kernel mass in this fraction. There is no limitation on the proportion of broken kernels for the first fraction, since a higher proportion (>30%) of broken kernels is actually advantageous for pressing the kernels, as the increased resistance of broken kernels to being conveyed by the screw during pressing simplifies the pressing process. Therefore, the proportion of broken kernels in the first fraction will advantageously be above 50%, and particularly advantageously above 70%. Brief description of the drawings

[0028] The proposed method is explained in more detail below using an exemplary embodiment in conjunction with the drawing. This shows: Fig. 1 is a schematic representation of an exemplary embodiment of the method. Example of implementation

[0029] In this example, as shown schematically in Figure 1 As shown, three fractions were obtained from sunflower seeds that were largely free of infestation, using an impact peeler, followed by several sieving, screening and sorting processes: 25 wt% of a high-purity first fraction, hereinafter referred to as core fraction (1), with a shell content of <0.1 wt%, 20 wt% of a second fraction, hereinafter referred to as core fraction (2), with a shell content of 10 wt%, 10 wt% of a third fraction, hereinafter referred to as core fraction (3), with a shell content of 30 wt% and 30 wt% of a shell fraction which had a shell content of 80 wt%.

[0030] The core fraction (1) was pressed at mild temperatures (<60 °C) to a residual oil content of 18 wt%. After filtration, a very mild and nutty-tasting, yellowish-colored edible oil was obtained, which, after removal of the turbidity, could be used as cooking oil.

[0031] The press cake was defatted with hexane and solventized at low temperatures below 80°C. The solid was then milled to analytical fineness (particle size predominantly <100 µm) in a laboratory mill and evaluated with regard to color and functional properties.

[0032] The protein flour obtained as the first protein ingredient (1P) had a protein content of 59% (factor 6.25) based on dry matter, a residual oil content of 2%, and a brightness value (L*) of 85 according to CIE L*a*b*. It had a neutral, slightly nutty taste. The protein in the preparation was 40% soluble at pH 7 and exhibited an emulsifying capacity of 480 ml per gram of protein. This makes this fraction suitable as a highly functional food ingredient for a variety of demanding applications.

[0033] The core fraction (2) was pressed at 90 °C to a residual oil content of 10 wt%. After filtration, a slightly bitter-tasting, slightly cloudy, yellowish-colored edible oil was obtained. It can be further processed into an edible oil by refining.

[0034] The press cake from this pressing was also defatted with hexane and desolated in a drying oven at a temperature of 110°C. The solid was then milled to analytical fineness (particle size predominantly <100 µm) in a laboratory mill and evaluated with regard to color and functional properties.

[0035] The protein flour obtained as the second protein preparation (2P) had a protein content of 54% (factor 6.25) based on dry matter and a residual fat content of 1.8%, exhibiting a brightness value (L*) of 68 according to CIE L*a*b*. It had a slightly bitter taste and caused a rough mouthfeel. The protein in the flour was 25% soluble at pH 7 and showed an emulsifying capacity of 320 ml per gram. Therefore, this fraction is not suitable for use as a food ingredient, but is suitable for demanding animal feed applications such as fish food or pet food.

[0036] The kernel fraction (3) was processed similarly to the kernel fraction (2). Due to the high proportion of husks, the oil was even darker and somewhat more bitter, necessitating refining.

[0037] The protein meal obtained as the third protein ingredient (3P) had a protein content of 39% (factor 6.25) based on dry matter and a residual fat content of 1.7%, exhibiting a brightness value (L*) of 40 according to CIE L*a*b*. It had a bitter taste and a very rough mouthfeel. The protein in the meal was 25% soluble at pH 7 and showed an emulsifying capacity of 250 ml per gram. Therefore, this fraction is only suitable for simple animal feed applications, e.g., for cattle.

[0038] The shell fraction obtained consisted predominantly (approx. 80%) of shells and some remnants of kernel flesh and was not further investigated, nor were the oil fractions obtained after hexane de-oiling.

[0039] In the present patent application, the following determination methods were used to quantitatively determine the specified properties or values: Protein content: The protein content is defined as the content calculated by determining the nitrogen and multiplying it by a factor of 6.25. The protein content can be expressed, for example, as a percentage of the dry matter (DM). Color: The perceptible color is determined using CIE L*a*b* color measurement (see DIN 6417). The L* axis indicates the brightness, where black has a value of 0 and white a value of 100; the a* axis describes the green or red component; and the b* axis describes the blue or yellow component. Protein solubility: Protein solubility is determined using the method according to Morr et al. determined in 1985 (see the journal article: Morr CV, German, B., Kinsella, JE, Regenstein, JM, Van Buren, JP, Kilara, A., Lewis, BA, Mangino, ME, "A Collaborative Study to Develop a Standardized Food Protein Solubility Procedure. Journal of Food Science", Volume 50 (1985) pages 1715-1718).The protein preparation is suspended in a 0.1 M NaCl solution at room temperature at a mass-volume ratio of 1:25 to 1:50 (w / v) (i.e., 1-2 g of the protein preparation per 50 ml of solution). It is then maintained at pH 7 for approximately 60 minutes using 0.1 M HCl or NaOH solution, stirring at approximately 200 rpm. The insoluble sediment is subsequently centrifuged for 15 minutes at 20,000 g (20,000 g) relative to gravity. Protein solubility can be expressed, for example, as a percentage, where a protein solubility of x% means that x% of the protein present in the preparation is recovered in the clarified supernatant when the aforementioned method is applied. Water binding capacity: The water binding capacity is determined using the AACC method as described in: American Association of Cereal Chemists, "Approved methods of the AACC". 10th ed., AACC. St. Paul, MN, 2000b; Method 56-20. "Hydration capacity of pregelatinized cereal products". The water-binding capacity is e.g.B. expressible in ml / g, i.e., milliliters of bound water per gram of preparation, and is determined according to the AACC determination method by subtracting the weight of the dry preparation from the weight of the water-saturated sediment after mixing approximately 2 g of protein preparation with approximately 40 ml of water for 10 minutes and centrifugation at 1000 g for 15 minutes at 20°C. Oil binding: The oil binding capacity is determined using a method as described in: Ludwig I., Ludwig, E., Pingel B., "A micromethod for determining fat binding capacity". Nahrung / Food, 1989, 33(1), 99. The oil binding capacity is e.g. B. can be expressed in ml / g, i.e. milliliters of bound oil per gram of preparation, and is measured according to the above determination method as the volume of the oil-binding sediment after mixing 1.5 g of protein preparation with 15 ml of corn germ oil for 1 minute and centrifugation at 700g for 15 minutes at 20°C.Emulsifying capacity: The emulsifying capacity is determined using the so-called conductivity measurement method, in which a 1% suspension of the protein preparation is added to 100 ml of corn germ oil (pH 7) until phase inversion of the oil-in-water emulsion occurs. The emulsifying capacity is defined as the maximum oil absorption capacity of this suspension, determined by the spontaneous decrease in conductivity upon phase inversion (see the journal article by Wäsche, A., Müller, K., Knauf, U., "New processing of lupin protein isolates and functional properties". Nahrung / Food, 2001, 45, 393-395) and can be expressed, for example, in ml oil / g, i.e., milliliters of emulsified oil per gram of protein preparation. Residual oil content: The residual oil content is determined using the Soxhlet method AOAC 963.15, i.e., by gravimetric determination after Soxhlet extraction.

Claims

1. Method for obtaining at least one protein preparation and several oil fractions from the seeds of sunflowers, which comprises at least the following steps: - providing or forming at least three fractions from the seeds, of which -- a first fraction has a shell content of <1 mass percent, -- a second fraction has a shell content of <20 mass percent, which is greater than the shell content of the first fraction, but is at least >0.3 mass percent, and -- a third fraction has a shell content of >60 mass percent, - separating oil from the first fraction through one or more de-oiling steps down to a residual oil content of <3 mass percent, with the result that one or more oil fractions and an oil-free first fraction as a first protein preparation are obtained, and - separating oil from the second fraction, with the result that one or more further oil fractions are obtained.

2. Method according to Claim 1, characterized in that forming the at least three fractions comprises the following steps: - shelling the seeds and - removing a part of the shells by sieving and / or winnowing and / or sorting in such manner that the at least three fractions are obtained with the stated shell contents.

3. Method according to Claim 1 or 2, characterized in that one or more further fractions is / are provided or formed that contain proteins from the kernels of the sunflower seeds, and from which oil and a protein-containing residue are then recovered, each having a protein content which is greater than a protein content of the shells.

4. Method according to any one of Claims 1 to 3, characterized in that the separation of oil from the first fraction is carried out by mechanical partial de-oiling of the first fraction to obtain a first oil fraction and a first residue fraction, und subsequent solvent extraction once or multiple times from the first residue fraction.

5. Method according to Claim 4, characterized in that the mechanical partial de-oiling is carried out at an average temperature of the first fraction below 80°C for the duration of the mechanical partial de-oiling to reach an oil content of >10 mass percent and <30 mass percent.

6. Method according to any one of Claims 1 to 5, characterized in that the provision or formation of the at least three fractions from the seeds takes place in such manner that the first fraction contains between 1 and 80%, advantageously between 5 and 35%, particularly advantageously between 15 and 25% of the quantity of kernels that are present in the starting material for the method.

7. Method according to any one of Claims 1 to 6, characterized in that the provision or formation of the at least three fractions from the seeds takes place in such manner that the third fraction has a shell content of >80 mass percent and <99 mass percent, advantageously <90 mass percent.

8. Method according to any one of Claims 1 to 7, characterized in that the provision or formation of the at least three fractions from the seeds takes place in such manner that the first fraction has a shell content von <0.5 mass percent, advantageously <0.1 mass percent.

9. Method according to any one of Claims 1 to 8, characterized in that the provision or formation of the at least three fractions from the seeds takes place in such manner that the second fraction has a shell content of <10 mass percent.

10. Method according to any one of Claims 1 to 9, characterized in that the separation of oil from the first fraction is carried out through the one or several de-oiling steps until a residual oil content of <2 mass percent is reached.

11. Method according to any one of Claims 1 to 10, characterized in that through the one or more de-oiling steps, oil is separated from the second fraction until a residual oil content of <10 mass percent, advantageously <3 mass percent is reached, as a result of which the one or more further oil fractions and an oil-free second fraction as a second protein preparation are obtained.

12. Method according to Claim 11, characterized in that the separation of oil from the second fraction is carried out by mechanical partial de-oiling of the second fraction.

13. Method according to Claim 11, characterized in that the separation of oil from the second fraction is carried out by mechanical partial de-oiling of the second fraction in order to obtain a second oil fraction and a second residue fraction, followed by solvent extraction once or multiple times from the second residue fraction.