PROTEIN INGREDIENT MADE FROM OILSEEDS OF SUNFLOWERS OR RAPE, AND THE PRODUCTION THEREOF

Abstract

A method for obtaining a protein ingredient for animal feed from seeds of sunflowers or rape includes shelling the sunflower seeds or rapeseeds up to a shell content of <2.5 wt %, mechanically partially extracting the oil from the shelled sunflower seeds or rapeseeds by pressing, up to a fat or oil content in the region of >6 and <25 wt %, and carrying out at least one extraction step for further extraction of the oil with at least one organic solvent or supercritical CO2, up to an oil content of less than 3.5 wt %; and subsequently desolventing, wherein at least one protein-denaturing treatment of the sunflower seeds or rapeseeds is carried out between the shelling of the sunflower seeds or rapeseeds and the obtaining of the protein ingredient. Due to its good digestibility, the protein ingredient can be used as an at least partial replacement for animal proteins in animal feeds.

Claims

1. A method for obtaining protein ingredients for animal feed from seeds of sunflowers or rape, with at least the following steps shelling the sunflower seeds or rapeseeds up to a shell content of <2.5 wt % to obtain shelled sunflower seeds or rapeseeds, or providing shelled sunflower seeds or rapeseeds having a shell content of <2.5 wt %; mechanical partial extraction of the oil from the shelled sunflower seeds or rapeseeds by pressing up to a fat or oil content in the range between >6 and <25 wt %; carrying out at least one extraction step for further extraction of the oil from the sunflower seeds or rapeseeds with at least one organic solvent or supercritical CO2 up to an oil content of less than 3.5 wt %, and subsequent desolventing, whereby a protein-containing product is obtained as a protein ingredient for animal feed, wherein at least one protein-denaturing treatment of the sunflower seeds or rapeseeds is carried out between the shelling of the sunflower seeds or rapeseeds and obtaining the protein ingredient in such manner that proteins contained in the protein ingredient are denatured to a percentage of >40%.

2. The method according to claim 1, characterized in that the protein-denaturing treatment is carried out by means of a temperature-time load in which proteins of the sunflower seeds or rapeseeds are exposed to a temperature higher than 90 C., preferably >100 C., and below 150 C. for at least 10 minutes (advantageously for over 30 minutes).

3. The method according to claim 1, characterized in that the mechanical partial extraction of oil from the shelled sunflower seeds or rapeseeds is carried out by pressing at an average temperature of the shelled sunflower seeds or rapeseeds of less than 80 C. over the duration of the pressing operation, and the at least one extraction step is also carried out at a temperature below 80 C., and that the protein-denaturing treatment is effected by a high temperature of >100 C. during the desolventing.

4. The method according to claim 1, characterized in that the protein-denaturing treatment is carried out by means of an aqueous-alcoholic treatment of proteins of the sunflower seeds or rapeseeds at a mass ratio of alcohol and water between 1:20 and 20:1 and a temperature above 40 C.

5. The method according to claim 1, characterized in that the mechanical partial extraction of oil from the shelled sunflower seeds or rapeseeds is carried out by pressing at an average temperature of the shelled sunflower seeds or rapeseeds of less than 80 C. over the duration of the pressing operation, the at least one extraction step is carried out at a temperature below 80 C., and the desolventing takes place at a temperature below 100 C., and that after the desolventing a treatment of proteins of the sunflower seeds or rapeseeds with an alcohol-water mixture is carried out and then the proteins are brought to a temperature >100 C.

6. The method according to claim 1, characterized in that the desolventing is carried out by distillation separation of the solvent, particularly with the introduction of heat by means of one or more superheated organic solvents and/or by the use of water vapour.

7. The method according to claim 1, characterized in that a temperature of >90 C., preferably >100 C., and below 150 C. is chosen for the desolventing.

8. The method according to claim 1, characterized in that the mechanical partial extraction of oil is carried out in such manner that a temperature of the shelled sunflower seeds or rapeseeds rises above a value of 75 C. during the mechanical partial extraction of oil.

9. The method according to any one of claim 8, characterized in that the temperature is chosen at such a value that a press cake obtained by the mechanical partial extraction of oil has a fracture pressure greater than 10 N/mm.sup.2.

10. The method according to claim 1, characterized in that a mechanical treatment of a press cake obtained by the mechanical partial extraction of oil is performed between the mechanical partial extraction of oil and the at least one extraction step.

11. A protein ingredient for animal feeds which is obtained from proteins of rapeseeds and has a solvent content, particularly a hexane content, between 0.0001 and 2 wt % and/or an alcohol content between 0.0001 and 2 wt %, a protein content of >45 wt % and <80 wt %, a fat content of <3.5 wt %, a protein solubility of <40%, a shell content less than 5 wt %, advantageously <2 wt %, particularly advantageously <0.5 wt %, a denaturing of >40% of the proteins, and a digestibility of >60% of the proteins.

12. A protein ingredient for animal feeds which is obtained from proteins of sunflower seeds and has a solvent content, particularly hexane content, between 0.0001 and 2 wt % and/or an alcohol content between 0.0001 and 2 wt %, a protein content of >45 wt % and <80 wt %, a fat content of <3.5 wt %, a protein solubility of <30%, a shell content less than 5 wt %, advantageously <2 wt %, particularly advantageously <0.5 wt %, a denaturing of >40% of the proteins, and a digestibility of >70% of the proteins.

13. A protein ingredient for animal feeds which contains a mixture of soya proteins with a protein ingredient according to claim 12 or a protein ingredient produced from sunflower seeds according to the method according to claim 1.

14. The protein ingredient according to claim 13, characterized in that a protein mixture ratio between the soya proteins and the proteins of the protein ingredient lies between 1:10 and 10:1, advantageously between 30:70 and 70:30, particularly advantageously at 50:50 relative to the protein content.

15. A substitute for animal proteins in animal feeds, said substitute comprising a protein ingredient produced with the method according to claim 1.

16. Animal feed for carnivorous animals comprising protein ingredient produced with the method according to claim 1, alone or in conjunction with other plant proteins as a primary source of protein.

Description

DESCRIPTION OF THE INVENTION

[0020] This problem is solved with the method according to Claim 1. The further claims describe preferred variants of the method, a protein ingredient that may be produced with the method, and the preferred use thereof in animal feeds.

[0021] In the present method for obtaining high-value protein ingredients from sunflower seeds and rapeseeds, first the seeds are shelled, and the shells are separated from the kernel, preferably by sieving, sifting and sorting, so that a shell content of <2.5 wt %, advantageously <1 wt %, particularly advantageously <0.25 wt % is obtained.

[0022] In order to change the protein solubility with the objective of obtaining denaturing effects in the protein, at least one protein-denaturing treatment must be carried out during the steps for processing the shelled seeds as far as the protein preparation with the oil removed (pressing, extracting, desolventing optionally grinding), in order to achieve a denaturing of the proteins contained in the protein ingredient to a proportion of >40%. This is understood to be either a temperature-time load which is characterized in that the sunflower or rape proteins are placed under load in the course of the processing for at least 10 minutes, advantageously for more than 30 minutes with a temperature of more than 90 C., advantageously over 100 C., advantageously over 110 C., particularly advantageously over 120 C. and under 150 C. Another protein-denaturing treatment according to the invention may be carried out also in addition to the temperature-time load in the form of an aqueous-alcoholic treatment of the protein in a mass ratio of alcohol to water between 1:20 and 20:1 and at a temperature higher than 40 C., preferably higher than 50 C. Monovalent alcohols such as methanol, ethanol, propanol, isopropanol or butanol may advantageously be used as alcohols.

[0023] With this protein-denaturing treatment following extensive shelling, it is ensured that for the application in animal feed only a very small content of shell and fibre is contained in the extracted press cake, other undesirable accompanying substances have been reduced, and at the same time the proteins are bound firmly in the remaining carbohydrate matrix of the kernel as a result of the (partial) denaturing, which considerably reduces protein losses along the value-added chain of the protein preparation until the feeding. This helps to ensure for example that when fed to fish in water the proteins are dissolved out of the protein preparation only very slowly, and consequently only small losses take place into the environment via aqueous phases.

[0024] For the further processing after the shelling, preferably after conditioning by setting temperature and moisture the shelled seeds are pressed to an oil content of <25 wt %, advantageously <15 wt % particularly advantageously <10 wt %, but >6 wt %, advantageously >9 wt % by pressing, and the press cake obtained by this mechanical partial oil removal then undergoes oil extraction by means of extracting agents (e.g., hexane, ethanol, supercritical CO.sub.2, ethyl acetate or mixtures thereof) up to an oil content (determined according to the Soxhlet method) of less than 3.5 wt %, advantageously less than 2 wt %.

[0025] In a preferred variant, the temperature should exceed a value of 75 C. at least in parts of the product during the pressing, advantageously a temperature of over 85 C., particularly advantageously over 95 C. is reached in the press cake during pressing. This may be assured for example by heating the press, by preheating the kernels or with high shearing forces and pressures in the press. This results in a significant increase in the speed at which the oil is removed, a denaturing of the proteins, and a solidification of the press residue. The consequence of the solidification of the press residues which takes place at elevated temperatures is that less abrasion takes place during the transportation of the residues between the individual oil removal process stages or in the subsequent oil extraction, accordingly fewer losses occur and also fewer problems arise during the processing of the miscella (oil-solvent mixture) as fewer fine abrasion particles are separated from the protein preparation via the miscella. Thus, the losses from abrasion are reduced and the process is rendered more efficient by the pressing according to the invention. In the process, for example a mechanical strength and/or fracture pressure greater than 10 N/mm.sup.2, measured with a Texture Analyzer (TA) under radial compressive load, is achieved in the pressure cakes for a round press cake strand with a diameter of 8 mm by correspondingly high temperatures.

[0026] After the extraction of the pre-pressed oil seeds with solvents, which should be carried out directly with the press cake or following an advanced mechanical treatment of the press cake (e.g., grinding and pelletising), the separation preferably by distillation of the solvent by desolventing is carried out preferably with the application of heat in the form of superheated organic solvents and/or by the use of water vapour. For the desolventing in one advantageous variant of the method according to the invention a temperature of >90 C. should be chosen. Advantageously, a temperature above 100 C., particularly advantageously above 120 C. and below 150 C. should be set in the heat transfer media. In this process, a further denaturing of the proteins takes place, which is above 40%, advantageously above 70%, particularly advantageously above 90%. The denaturing of the protein is determined by DSC, as described in EP 2 400 859 A2 for example. With this method, when the denaturing is determined the DSC peak area (enthalpy) is determined in comparison with the peak area in untreated seeds, standardised to the protein content. The denaturing corresponds to area loss, i.e., no more area appears for 100% denaturing.

[0027] The high degree of denaturing and the reduced solubility of the sunflower protein or rapeseed protein resulting therefrom prompt the expectation of reduced bioavailability and poorer quality properties compared with native proteins, as is known from extraction residues according to the related art (S. Gonzalez-Perez, 2007: Sunflower proteins: overview of their physicochemical, structural and functional properties. Journal of the Science of Food and Agriculture 87(12); A. Moure et al., 2006: Functionality of oilseed protein products: A review, Food Research International, Volume 39, Issue 9). However, when a denatured protein ingredient after the treatment according to the invention is used, surprisingly it was found in testing with animals, for example when used to feed trout that despite a decrease of the protein solubility to less than 40% at pH 7 and a denaturing of more than 60% the protein digestibility reaches more than 80% in some cases, very much higher than that of extraction residues according to the related art. Extraction residues according to the related art also have low solubility and high denaturing, but consistently have a shell content greater than 10 wt %.

[0028] In order to determine the digestibility in this case, fish are fed with experimental rations, and the excrement is recovered by skimming. The digestibilities are calculated in accordance with the NRC recommendations (National Research Council. 2011. Nutrient Requirements of Fish and Shrimp. Washington, D.C.: The National Academies Press. https://doi.org/10.17226/13039).

[0029] Thus, the reduction of the shell content in the extraction residues seems to affect the digestibility of the proteins in the feeding tests disproportionately. At the same time, a target of less than 5 wt % should be set for the shell content in the residue after the oil has been removed, and a reduction to less than 2 wt %, advantageously less than 0.5 wt % shells brings further significant advantages in terms of digestibility. This low shell content is achieved in the suggested method by the provision of shelled sunflower seeds or rapeseeds with a shell content of <2.5 wt %, advantageously <1 wt %, particularly preferably <0.25 wt % for the mechanical partial oil removal, since the extraction residues from rapeseeds or sunflower seeds after the oil has been removed correspond to only about 50% of the mass of the rapeseeds and sunflower seeds.

[0030] Thus, the use of the protein preparations from rapeseeds or sunflower seeds according to the invention presents itself favourably as a high-value alternative for animal proteins such as fish meal, animal meal, blood meal or feather meal. Replacement rates from 35% up to advantageously 60%, still more advantageously up to 80%, particularly advantageously up to 100% of animal meals with the protein ingredient according to the invention appear reasonable and possible. Such a substitution up to a largely complete replacement of animal components in animal feed is of great advantage not only for reasons of sustainability but also profitability.

[0031] A very good digestibility of the protein is assured by the method according to the invention despite the extensive protein denaturing due to the high temperatures. This is also demonstrated when the method described is followed by treatment with alcohol-water mixtures with the purpose of separating secondary plant substances (e.g., polyphenols) of which have an active taste component and are to a certain extent anti-nutritional. Despite an even more extensive denaturing of the proteins to more than 80% by this process step, the digestibility remains almost unchanged. In experiments it was found that when these protein ingredients from rape or sunflower are used as animal feed, a weight gain by the animals follows which is comparable to conventional animal feeds with the same protein content. It therefore seems particularly advisable to add an alcohol-water extraction step after the oil removal in order to obtain good animal feed properties.

[0032] Particular benefits are also gained if the denaturing step is performed not immediately at the start of the treatment, that is to say during the pressing, but if a less intense pressing with a medium temperature of the kernel fraction is initially carried out for the duration of the pressing operation below 80 C., advantageously below 70 C., and the oil extraction also takes place below 80 C., and then a thermal denaturing is performed with a high temperature during desolventing at >100 C., advantageously >120 C. It may also be beneficial to dispense with thermal step >100 C. after the oil is removed, and not to introduce an elevated temperature >100 C. until after a treatment of the protein with an alcohol-water mixture has been completed. In this way, the protein can be denatured more effectively still.

Properties of Rape Protein

[0033] According to the method, a protein ingredient made from rapeseeds and produced with the method has the following properties (the analytical methods are described in EP 2 400 859 A2 and elsewhere): [0034] Hexane content between 0.0001 and 2 wt % and/or [0035] Alcohol content between 0.0001 and 2 wt % [0036] Protein content >45 wt % and less than 80 wt % (determined with Dumas N*6.25) [0037] Fat content <3.5 wt % (determined with hexane in the Soxhlet method) [0038] Protein solubility <40%, advantageously <25%, particularly advantageously <20% (method according to Morr et al. 1985 and determination of the NSI) [0039] Shell content less than 5 wt %, advantageously <2 wt %, particularly advantageously <0.5 wt %, [0040] Denaturing the protein: >40%, advantageously >70%, particularly advantageously >80%, (determined by DSC) [0041] Digestibility of the protein: >60%, advantageously >80%

Properties of Sunflower Protein

[0042] A protein ingredient made from sunflower seeds and produced with the method has the following properties according to the invention (determined by the same determination method as for the rape protein): [0043] Hexane content between 0.0001 and 2 wt % and/or [0044] Alcohol content between 0.0001 and 2 wt % [0045] Protein content >45 wt % and <80 wt % (determined with Dumas N*6.25) [0046] Fat content <3.5 wt % (determined with Soxhlet method) [0047] Protein solubility <30%, advantageously <25% or <20% [0048] Shell content less than 5 wt %, advantageously <2 wt %, particularly advantageously <0.5 wt %, [0049] Denaturing of the protein: >40%, advantageously >70%, particularly advantageously >80%, [0050] Digestibility of the proteins: >70%, advantageously >85%

[0051] Because of its good digestibility in animal feeds, a protein preparation according to the invention made from sunflowers can be used instead of the animal protein source (e.g., fish meal, blood meal, feather meal, etc.) in considerably higher concentrations than is possible with residues from sunflower oil recovery according to the related art, even though traces of organic solvents can still be detected in the animal feed.

[0052] In feeding experiments, the proportion of the preparation form sunflower seeds can replace up to 50% of the animal components in conventional feed with having to accept significant sacrifices in terms of animal growth. In the case of rapeseeds as well, a relatively high rate of substitution of animal components is possible, in this case the limit is at 45% in the animal feed after simple removal of the oil from the rape component using hexane. After further treatment with alcohol-water mixtures, the replacement of animal components with oil seed ingredients can be raised to 60% and still delivers financially reasonable growth rates.

[0053] Thus it is possible to prepare an animal feed with high rates of substitution of animal components with the protein preparations according to the invention. Animal feeds according to the invention from rapeseeds enable substitution rates higher than 30% with the protein ingredients from rape according to the invention, particularly advantageously higher than 40%, particularly advantageously higher than 45%. Animal feeds according to the invention from sunflower seeds enable substitution rates higher than 30% with the protein ingredients from sunflowers, particularly advantageously higher than 40%, particularly advantageously higher than 50%.

[0054] In a particularly advantageous variant of an animal feed according to the invention for carnivorous animals (e.g., salmon, trout), animal components are replaced entirely by a preparation from sunflower seeds according to the invention having a shell content <3.5 wt %. In this context, animal growth losses of up to 20% and lower digestibility compared to animal protein ingredients were found. Surprisingly however, it has been found that the animals fed with these animal feeds enjoy very high consumer acceptance despite reduced body weight and lower muscle protein. It is therefore advantageous to dispense with the addition of animal components despite the lower quality and to compensate for the possible deficits by the use of special amino acid or vitamin and mineral mixtures.

[0055] For use in animal feeds, it is helpful to mix the protein ingredients according to the invention with additional ingredients such as vitamins, minerals, amino acids/and/or proteins, sensory additives (colouring and flavouring substances), zootechnical additives (enzymes, prebiotics, . . . ), technological additives (e.g., binders, acidity regulators, . . . ) and oils.

[0056] In an advantageous variant of the use of the protein ingredient according to the invention as animal feed, the ingredient from sunflowers is mixed with soya protein for use as animal feed. The ratio of protein to mixture is then advantageously between 1:10 and 10:1, particularly advantageously between 30:70 and 70:30, very advantageously at 50:50 relative to the protein content. Surprisingly, it has been found that when both sunflower and soya are used good growth can be achieved, which delivers particularly high results due to the described properties of the sunflower preparation.

EXEMPLARY EMBODIMENT

[0057] In order to produce an ingredient from sunflower kernels, the kernels were shelled to a residual shell content of <1 wt % and after setting a moisture of 5 wt % in the shelled sunflower kernels the oil was removed from them in a screw press at 95 C. to a residual fat content of 10 wt %.

[0058] This was followed by two different steps for mechanical post-treatment of the press cake to improve the oil extraction, once by flocking and once by pelletising after grinding.

[0059] A subsequent oil extraction process with hexane was carried out to a residual fat content of 2 wt % and desolventing of the hexane for 20 minutes with water vapour which was set to a temperature of 120 C. Following this, an extraction step with EtOH water in a mixture ratio of 50-50 by weight was carried out for 1 hour. The repeated desolventing of the EtOH water mixture was again carried out with water vapour at a temperature of 120 C. Then, the samples were ground finely for analysis. The ingredients obtained thereby had a protein solubility of 25% and a denaturing of 85%.

[0060] They were subsequently mixed with soya protein in a ratio of 20 wt % sunflower protein to 80 wt % soya protein and this mixture was added to salmon animal feed.