Improved method for producing high quality blood meal

Abstract

The present invention relates to a method of producing blood meal comprising the steps of (i) providing an aqueous mixture comprising raw blood, preferably having a solids content of about 5 wt% to about 18 wt%, and (ii) increasing the solids content of the mixture to obtain a mixture having a solids content of about 20 wt% or more, preferably about 20-80 wt%, and (iii) simultaneously drying and grinding the resulting mixture in an air turbulence mill to obtain a blood meal having an average particle size (d50) of between 20 [mu] m and 0.7 mm, d90 of less than 1 mm, and an ileum digestibility of about 85% or more, preferably about 87% or more, more preferably about 90% or more, as measured by laser diffraction using a dry powder Beckman Couter particle size analyzer, to obtain a blood meal having an average particle size (d50) of between 20 [mu] m and 0.7 mm, a d90 of less than 1 mm, and an ileum digestibility of about 85% or more, preferably about 87% or more, more preferably about 90% or more. The invention also relates to coagulated blood powder products with high ileum digestibility.

Description

[0001] (This application is a divisional application of application No. 201980020668.3, filed on January 22, 2019, entitled “Improved Method for Producing High-Quality Blood Meal”) Technical Field

[0002] The present invention relates to a method for producing high-quality blood meal and also relates to blood meal and use of the blood meal in feed. Background Art

[0003] Except for the collection of food-grade blood from pig and cattle slaughterhouses by special means (such as a hollow knife directly injected with anticoagulant), blood is generally a low-priced by-product from slaughtered poultry, ducks, pigs, cattle, sheep, etc., although it is rich in digestible protein. However, the processing of blood usually reduces its nutritional value and / or the processing is relatively expensive. However, it must be processed to obtain a shelf-stable powdered material. This shelf-stable material is usually called "blood meal".

[0004] Several methods for processing plasma and / or anticoagulated blood have been described, such as in US 2015 / 056363. However, the use of anticoagulated blood requires the addition of an anticoagulant immediately after blood is drawn from the animal at the slaughterhouse. WO 01 / 08501 A1 describes a method and system for collecting blood without clotting, particularly poultry blood.

[0005] Furthermore, spray drying technology is used for blood for medical purposes, as described, for example, in US 2012 / 027867.

[0006] Another method of drying blood for human consumption is, for example, freeze drying, as described for deer blood in CN1994319.

[0007] Anticoagulated blood is typically separated into a plasma fraction and a hemoglobin fraction, and both streams are further dried via spray drying, resulting in a product with excellent nutritional value. However, production is complex due to the need for slaughterhouse involvement, and spray drying is expensive. Furthermore, the presence of anticoagulants often results in additional ash content or organic matter, which reduces the amino acid value of the product.

[0008] If special measures are not taken to prevent coagulation, slaughterhouses will provide partially coagulated blood as a by-product. This blood by-product is naturally coagulated while still containing dissolved proteins, such as plasma proteins. This blood by-product is obtained by collecting a waste blood stream, and due to water purification, this side stream is usually diluted with water. This blood by-product is generally a heterogeneous mixture of coagulated and uncoagulated blood particles, blood compounds, blood proteins, partially hemolyzed blood cells and additional water, and its solids content is generally about 5-18% by weight.

[0009] This (partially coagulated) blood byproduct is typically processed to first obtain completely coagulated blood. This complete coagulation is typically achieved by steam treatment, a step typically performed in a blood meal production facility. Typically, the coagulated blood is then subjected to a concentration step and dried in a disk dryer, ring dryer, or the like.

[0010] Continuous production methods for providing blood meal from coagulated blood are described, for example, in US Pat. No. 3,431,118 and US Pat. No. 3,450,537. US Pat. No. 4,067,119 describes the use of a drum dryer, while GB 2,303,042 describes the now common method of coagulation, decanting (and / or centrifuging), drying in a disk dryer, and grinding to particles of about 1 mm in size. Furthermore, it is known to dry coagulated blood in annular or flash dryers, in which the blood particles are blown into a drying tube.

[0011] Blood meal can be used as a protein supplement in feeds such as pet food, aquaculture feed, etc.

[0012] Especially for industrial applications, such as aquaculture feed, high nutritional value is crucial. Such products, for example, require high protein digestibility, which can be achieved through spray drying, albeit at a high cost. Spray-dried material is currently the benchmark for high-quality blood meal. Summary of the Invention

[0013] The object of the present invention is to provide a method for producing blood meal from raw whole blood, raw hemoglobin and / or raw plasma fractions, which has a high nutritional value and can be produced efficiently.

[0014] Another object of the present invention is to provide a blood meal made from coagulated blood that has a higher digestibility and preferably better other properties than heretofore available.

[0015] The objects of the present invention are achieved by a method for producing a blood meal, comprising the steps of: (i) providing an aqueous mixture comprising raw blood, preferably having a solids content of about 5 wt% to 18 wt%, and (ii) increasing the solids content of the mixture to obtain a mixture having a solids content of about 20 wt% or more, preferably about 20-80 wt%, and (iii) simultaneously drying and grinding the resulting mixture in an air turbulence mill to obtain a dry blood meal having an average particle size (d50) between 20 μm and 0.7 mm, a d90 of less than 1 mm, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, and an ileal digestibility of about 85% or more, preferably about 87% or more, more preferably about 90% or more.

[0016] The present invention also provides a coagulated blood meal product having an average particle size (d50) between 20 μm and 0.7 mm and a d90 of less than 1 mm, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, and having an ileal digestibility of about 85% or greater, preferably about 87% or greater, even more preferably about 90% or greater, and a moisture content of less than 15 wt%, preferably less than 10 wt%.

[0017] The methods and products of the present invention can achieve many advantages:

[0018] Efficient drying in a short time results in a product with excellent quality attributes, such as an ileal digestibility of preferably 85% or more, or even 87% or more, such as 90%. Typically, the ileal digestibility of disc-dried coagulated blood is 60-75%, while the ileal digestibility of flash-, ring- or drum-dried material can be as high as 84%.

[0019] Furthermore, the product may have an apparent digestibility coefficient (ADC) on trout based on crude protein of about 80% or more, preferably about 85% or more, and even more preferably 87% or more.

[0020] Furthermore, the utilization of lysine appears to be high. Lysine is an amino acid that often limits growth in poultry and pigs. Products prepared using the methods of the present invention typically have a lysine utilization of about 92% or more, preferably about 95% or more, relative to the total lysine content.

[0021] Furthermore, the product obtained by the method of the present invention can have a more uniform, lighter color with almost no black spots.

[0022] Also, the odor is improved (less odor) relative to traditional blood meals.

[0023] This method is more efficient because up to five operations can be performed in a relatively simple apparatus. In conventional processes, drying, grinding, micronization, cooling, and sieving are performed in separate steps, but this method allows all five steps to be performed in a single operation. Furthermore, short residence times of just a few seconds are possible.

[0024] The method can be used with anticoagulated blood, raw hemoglobin, and / or raw plasma fractions as an alternative to spray drying, with the advantage of requiring much smaller equipment.

[0025] The method of the present invention has the additional benefit of significantly reducing the risk of microbial contamination of the dried product by, for example, Salmonella. Due to the high speed of the rotor and the turbulence generated by the air flow, there are no dead zones in the air turbulence mill, and the temperature of the air flow can be easily increased (if necessary) before, during, or after a production run. This is an important factor in avoiding product accumulation or cold spots, thereby preventing and mitigating microbial contamination.

[0026] In another aspect of the present invention, the feed stream to the air turbulence mill is treated to be pasteurized or even sterilized. This treatment preferably includes a heat treatment at a sufficiently high temperature for a sufficiently long time, given the moisture content of the stream, to obtain a pasteurized or sterile product stream. The combination of a sufficiently high temperature for a sufficiently long time, given a given solids content, is well known to those skilled in the art. The pasteurization or sterilization step can be performed in a separate heat exchanger and / or can be integrated with existing process steps.

[0027] The method does not require any special measures at the slaughterhouse, such as would be necessary to obtain non-coagulated blood for spray drying, but rather anticoagulated blood, raw hemoglobin and / or raw plasma fractions can be used and mixed with (partially) coagulated blood, or as a separate supply. DETAILED DESCRIPTION

[0028] The term "about" means plus or minus 20%, preferably plus or minus 10%, more preferably plus or minus 5%, and most preferably plus or minus 2%.

[0029] raw material

[0030] Raw blood can be obtained from various animals processed in slaughterhouses, such as poultry (including chickens, turkeys), ducks, pigs, livestock (including cattle, horses, goats), sheep, etc. A mixture of animal blood can be used.

[0031] As used in the present invention, "raw blood" may refer to the main fraction of blood, such as hemoglobin, plasma, or a mixture of these and whole blood.

[0032] In a preferred embodiment, the raw blood is derived from chicken, turkey, duck, pig, sheep or cow or a mixture thereof.

[0033] Raw blood is usually collected from slaughterhouses as anticoagulated blood, or as a mixture of partially clotted blood (clotted blood particles), dissolved proteins, partially hemolyzed blood cells and water (together referred to as: partially clotted blood).

[0034] Food-grade blood is typically drawn from animals (primarily pigs and cattle) using a "hollow knife" that is inserted directly into the animal's jugular vein and an anticoagulant is injected directly into the knife or a few centimeters behind it; in other cases, blood drips into a collection channel and the anticoagulant is continuously sprayed over the blood stream.

[0035] Non-food grade blood is typically not anticoagulated and will drip from the animal directly onto the floor or onto a collection plate, which is periodically flushed with water to help the blood flow to the discharge point, where a pump then picks up the blood and pumps it into a holding tank.

[0036] Although anticoagulated blood, raw hemoglobin and / or raw plasma fractions are generally of food quality, batches may not meet standards, and such anticoagulated raw blood or fractions thereof may be used as such or mixed with partially coagulated blood in the methods of the present invention to provide a feed additive.

[0037] Alternatively, food quality anticoagulated blood, raw hemoglobin and / or raw plasma fractions may be processed according to the methods of the present invention to produce food quality blood meal.

[0038] Although other solids contents may be used to practice the present invention, the amount of solids in raw blood is generally between about 5 wt% and 18 wt%, and typically between 8 wt% and 12 wt%.

[0039] Blood from animals typically has a solids content of about 17% to 19% by weight. Because the raw, usually non-food-grade blood is diluted with flushing and cleaning water from the slaughterhouse's blood collection and drainage systems, the solids content will be less than 17% by weight, typically less than 14% by weight, but more likely around 12% by weight or less. In poultry slaughterhouses, additional blood dilution water can come from drippings from the birds' heads shortly after leaving the waterbath in the electrical stunning station.

[0040] The raw blood used in the present invention preferably has a high protein content (typically greater than 80% by weight of dry matter) and contains at least 17 amino acids. Protein content is typically determined by measuring the total amount of nitrogen and multiplying it by the so-called Jones factor of 6.25. The result is the theoretical amount of protein. Typically, raw blood contains 80% to 95% protein on a solid basis.

[0041] Preferably, if anticoagulated blood is processed, it can be used as is or can be fractionated. In some methods, the plasma is separated from the hemoglobin fraction by, for example, centrifugation. The hemoglobin fraction (due to separation from the plasma) has an increased solids content relative to the original blood and is typically about 30-40% solids by weight. With this increase in solids content, the hemoglobin fraction can be used as feed to an air turbulence mill, or the solids content can be further increased as described below for other blood fractions.

[0042] After separation of the hemoglobin fraction, the plasma fraction of the anticoagulated blood is typically between 4-8 wt% solids and needs to have its solid content increased, for example, by ultrafiltration, to a solid content of 25-30 wt%. This mixture can be further processed into other blood mixtures described below.

[0043] Preferably, the raw blood, in particular non-anticoagulated raw blood, is first filtered on a mobile or non-mobile filtering device to remove foreign matter, such as animal parts (mainly feathers and heads) and crop residues.

[0044] The solids content of the raw blood is increased to allow for efficient drying in the air turbulence mill. Preferably, the solids content is increased by 10% or more, preferably by 20% by weight or more, for example, from 18 to 28% by weight (a 10% increase) or from 12% to 32% by weight (a 20% increase). Even more preferably, the increase in solids content is about 30% by weight or more. As will be appreciated from the above, the raw blood does not necessarily reflect the entire raw blood composition, but can be a portion thereof.

[0045] In a preferred embodiment, the solids content of the blood is increased to between about 20 and about 60 wt%, preferably between about 40 and about 60 wt%.

[0046] In a first preferred embodiment, the raw blood is treated to (further) coagulate the blood and subsequently increase the solids content.

[0047] The coagulated blood thus obtained is referred to as completely coagulated blood or clotted blood. In practice, not all of the protein content is coagulated, but the amount of coagulated or denatured proteins is significantly higher than in a partially coagulated blood mixture or anticoagulated blood.

[0048] Coagulation can be performed mechanically using heat, steam, and / or chemicals. Chemical coagulation of industrial animal blood can be achieved using, for example, aluminum sulfate, zinc sulfate, methanol, and acetone (see Andrew L. Ratermann, H. Wayne Burnett, Vaughn Vandegrift; J. Agric. Food Chem., 1980, 28: 438–441).

[0049] Preferably, coagulation is performed by mechanical and / or thermal treatment.Even more preferably, the partially coagulated blood is further coagulated by direct contact and mixing with live steam.

[0050] Further coagulation also serves to homogenize the partially coagulated blood mixture.

[0051] The coagulation process is preferably carried out in such a way that the raw blood produced is considered to be sufficiently pasteurized or even sterile. The coagulation process is preferably carried out at a temperature of above 80°C, preferably above 90°C, and even more preferably above 95°C, for a sufficient time, generally referred to as the heat death time, to achieve pasteurization or sufficient sterilization of the product stream. The temperature is generally about 150°C or lower. Depending on the temperature of the treated product stream, the sufficient time may be between a few seconds and an hour or more. As is well known to the skilled person, higher temperatures require shorter treatment times. Generally, a time of about half an hour or less will be preferred, and a time of about 10 minutes or less will be more preferred. Generally, a time of 1 minute or more, for example 2 minutes or more, or 3 minutes or more, is acceptable.

[0052] For example, a suitable temperature / time combination can be achieved by using steam treatment for the coagulation step. Such high temperature treatment preferably comprises direct steam injection, which raises the temperature of the product stream to about 80°C or higher, or preferably 90°C or higher, even more preferably about 95°C or higher, and maintains the coagulated blood stream at a temperature of about 80°C to 95°C or higher, for example for a total period of between 2-10 minutes.

[0053] Preferably, pasteurization conditions are such that at 10 wt% solids give a temperature / time treatment at least equivalent to treatment at 85°C, preferably 90°C, or even more preferably 95°C for 2 minutes.

[0054] More generally, known treatments for pasteurizing or sterilizing milk or juice can be applied to raw blood, including anticoagulated blood, specific fractions of blood, partially coagulated blood, clotted blood, or mixtures thereof.

[0055] Preferably, the material stream after the pasteurization / sterilization step complies with the requirements of the Animal By-Products Regulation (No. 1069 / 2009 and No. 142 / 2011) regarding Salmonella and Enterobacteriaceae and Clostridium perfringens. Preferably, the mixture comprising the raw blood is treated at a sufficiently high temperature and for a sufficient time to reach the thermal death time of Salmonella and Clostridium perfringens and to make Salmonella and Clostridium perfringens undetectable using standard assays according to the Animal By-Products Regulation.

[0056] The clotted blood is preferably dehydrated to increase the solids content of the clotted blood to about 20-60 wt% solids on a dry basis, preferably 40-60% solids on a dry basis. Water can be removed by evaporation, mechanically by pressing the blood clot onto a sieve, centrifugation, or using ultrafiltration. The clotted blood is preferably centrifuged to remove water from the clotted blood. Evaporation can be performed, for example, under reduced pressure, for example at a temperature of 30-60°C.

[0057] In addition, the solids content can be further increased by drying in conventional drying equipment, for example to 80 wt% solids, or more preferably to a point where the digestibility of the semi-dried product will begin to decrease significantly. Such moisture content will vary depending on the type of pre-drying equipment used. In a preferred embodiment, the solids content is increased to about 60%.

[0058] The residual water, often referred to as blood water, resulting from, for example, centrifugation, can contain 1 to 5 wt% or typically 1 to 4 wt% solids. Blood water is a waste stream that can be concentrated to, for example, 15-40 wt% solids using ultrafiltration, and the concentrated stream can be spray-dried, for example, but is preferably recycled into the production process for drying in an air turbulence mill. Alternatively, blood water can be considered a waste stream that can be treated in a wastewater treatment plant.

[0059] Preferably, the dried blood meal material is back-mixed with the concentrated blood water stream and this mixture can be fed directly to the air turbulence mill, or it can be mixed with the main clotted blood stream and then enter the air turbulence mill.

[0060] When using clotted blood, it may be useful to mix the dry blood meal product back into the feed stream of the air turbulence mill in order to (further) increase the solids content of the feed to the air turbulence mill in this way.

[0061] In a second alternative preferred embodiment, raw blood obtained from a slaughterhouse may be homogenized and the solids content increased without further coagulation, for example with live steam.

[0062] Homogenization is particularly useful when processing partially coagulated blood because it is a heterogeneous material. Homogenization can be performed in the container or by conventionally available mixing equipment (such as a mixer) when the blood mixture is transferred to the turbulent flow mill. Preferably, large particles greater than 1 cm in size are reduced in size during the homogenization step.

[0063] This increase in the solids content of the raw blood can be achieved, for example, by back-mixing the blood meal into the feed stream of the air turbulence mill and / or by evaporating water from the mixture.

[0064] The increase in solids content is preferably achieved at least in part by backmixing the blood meal into the blood mixture supply stream prior to introduction into the air turbulence mill. The increase in solids content can also be achieved by evaporating water under reduced pressure. It is preferred that the temperature during these treatments be maintained at about 100°C (boiling water temperature) or less, preferably 80°C or less, preferably about 70°C or less, and even more preferably about 60°C or less.

[0065] Thus, typically, a raw blood mixture obtained from a slaughterhouse can be homogenized and the solids content increased from less than 14 wt%, typically from less than about 10 to 12 wt%, to at least 20 wt%, more preferably to about 40 wt% or more, for example up to 50 wt%, by removing water and / or by adding dried blood meal and / or concentrated blood mixture to the feed stream of an air turbulence mill.

[0066] If water is removed from the original blood mixture, for example by evaporation as part of the step of increasing the solids content, the solids content of the stream fed to the air turbulence mill is typically about 20-40 wt%, such as about 30 wt%, before the back-mixing stream is added.

[0067] If blood meal is added to the original blood stream as the only means of increasing the solids content, the solids content of the mixed stream entering the air turbulence mill will typically be about 50 wt% or less.

[0068] The homogenized at least partially coagulated blood, the solids content of which is increased to preferably more than 40 wt %, can then be dried as a mixture in an air turbulence mill.

[0069] In one embodiment of the present invention, the clotted blood mixture is supplied to the air turbulence mill while its moisture content is preferably 40-60 wt%.

[0070] In another embodiment, after the solids content is increased, the optionally homogenized raw blood mixture is supplied to an air turbulence mill at a solids content between 20-55 wt%, preferably 30-50 wt%.

[0071] Drying process and air turbulence mills and their accessories

[0072] The blood mixture with increased solids content is dried and ground according to step (iii) of the present invention.

[0073] Typically, the blood mixture is dried to a moisture content of about 15 wt% or less. In a preferred embodiment of the present invention, the blood mixture is dried to a moisture content of about 10 wt% or less, preferably about 8 wt% or less. Drying to a moisture content below about 4 wt% is generally unnecessary but does not cause harm. Most preferably, drying is performed so that the dried blood meal has a moisture content of about 5 to 7 wt%. Drying produces a storage-stable product.

[0074] In a preferred embodiment, the dried blood meal is separated into a product stream and a recycle stream.

[0075] The product leaving the air turbulence mill may contain a relatively small proportion of ultrafine product, material that is too coarse to be ground or other unsuitable material, which is preferably separated in a classifier. Unsuitable material is preferably recycled (backmixed) into the feed stream of the air turbulence mill.

[0076] Preferably, if extensive backmixing can be used, a portion of the appropriate product is used as a recycle stream to be mixed back into the feed to the air turbulence mill.

[0077] According to the present invention, a recirculation stream (backmixing of dried blood meal) can be used to increase the solids content of the feed stream entering the air turbulence mill.

[0078] Drying is an important step in determining the final quality of blood meal.

[0079] It appears that common drying techniques used to clot blood result in reduced digestibility.

[0080] In a preferred embodiment of the present invention, the drying of step (iii) is carried out at about atmospheric pressure, while forming small particles, making the drying very effective. Atmospheric pressure includes a slight vacuum, which is generally used to assist gas flow and the conveying of powder. The powder can be recovered from the drying cyclone separator by an airlock rotary valve. The pressure before grinding can be -5 to -8 mbar, and the pressure after grinding is -30 to -50 mbar.

[0081] For example, drying in a conventional tray dryer typically produces an ileal digestibility of about 60-75%.The ileal digestibility of ring-, flash-, or drum-dried blood meal (also known as flash dried meal) is about 84%.

[0082] Preferably, the concentrated blood mixture obtained from step (ii) is dried using a method that allows low thermal damage, so that the reduction in digestibility during drying is limited and the blood meal is characterized by an ileal digestibility that remains above 85%, preferably about 87-93%, such as 90-92%.

[0083] Preferably, the concentrated blood mixture resulting from step (ii) is dried in a method that allows for low heat damage so that the blood meal preferably has an apparent digestibility of trout (ADC) of about 85% or more based on crude protein.

[0084] For example, drying in a conventional disc dryer typically produces a blood meal having a trout ADC of 65% or less based on crude protein.

[0085] In order to obtain such a material with low thermal damage, the inventors have discovered that it is necessary to carry out the drying under an air flow while grinding the material so that its residence time is very short.

[0086] The present inventors have found that further improvements in the in vitro digestibility and nutritional properties of blood meal can be achieved by using an air turbulence mill, as the small particles produced by the grinding action facilitate rapid drying of the concentrated blood mixture and thereby limit exposure of the product to heat.

[0087] Thus, according to the present invention, an air turbulence mill is used to simultaneously dry and grind the solid-enriched blood mixture obtained in step (ii) using a gas stream, typically air (which may have a low oxygen content). The gas may also be superheated steam. An air turbulence mill has the advantages of rapid grinding and drying effects, and the use of an air turbulence mill according to the present invention results in drying and simultaneous grinding or pulverizing of the blood mixture by introducing the material to be dried and a gas stream (typically air) into a high-speed rotor in a closed chamber.

[0088] Air turbulence mills typically consist of a chamber (stator) with appropriate inlets and outlets for the product and gas streams, in which a rotating member (rotor) is mounted with a stack of impact devices, which can rotate at high speeds. The inner wall of the stator is preferably lined with impact members, such as corrugated plates, to increase grinding efficiency through additional friction and shear forces. The rotor is usually positioned vertically relative to the outlet.

[0089] There are several types of air turbulence mills. They are often referred to as turbulent air mills or vortex air mills. The present invention contemplates the use of all of these under the term "air turbulence mill." Vertically positioned rotors are preferred, as these tend to consume less energy.

[0090] Air turbulence mills can be used, such as those known in the art from Atritor (Cell Mill), Hosokawa (Drymeister), Larsson (Whirl flash), Rotormill or Those of Mahltechnik (TurboRotor) are used for drying and grinding in the present invention. Some such air turbulence mills are described in, for example, US 4747550 and WO 1995 / 028513.

[0091] The air turbulence mill can include a classifier that separates larger and smaller particles. The classifier allows larger particles to be returned to the mill while smaller particles are retained for further processing. In another embodiment, by providing two outlets outside the classifier, two or more grades of granular blood meal with different particle size and volume characteristics can be produced.

[0092] The drying is performed by means of a gas stream into the high speed rotor. The gas stream is usually air, which can have a low oxygen content, but can also be superheated steam. The inlet temperature is usually between about 20°C and 500°C, preferably between about 20°C and 450°C, even more preferably between about 20°C and 180°C. The higher end of the temperature can require careful handling and / or can require the use of a smaller amount of heated gas. For example, heated gas can be used at a temperature of about 450°C, and a second gas stream at room temperature if a high gas velocity is required.

[0093] The outlet temperature of the air is usually below 100°C, preferably below 90°C. In case the concentrated blood mixture feed has a higher temperature, the temperature of the inlet gas can be lower.

[0094] The flow rate of the air is usually about 5 m 3 / h or more per kg of feed material, preferably about 7 m 3 / h per kg of feed material. Usually, the amount is about 50 m 3 / h or less per kg of feed material, preferably 30 m 3 / h or less. A suitable most preferred amount is for example 5-30 m 3 / h, for example 7-20 m 3 / h per kg of feed product.

[0095] The gas stream can be fed into the mill directly or indirectly together with the feed material, wherein the concentrated blood mixture is fed in one place and the gas stream is fed in one or several other places separately into the air turbulence mill. For example, the product can be fed directly into the lower side of the mill, or it can be mixed with the gas stream before the mill. Alternatively, the product feed can be fed directly through the inlet flanges at the side of the mill body.

[0096] The air turbulence mill used in the present invention preferably comprises a closed chamber (stator) with appropriate inlets and outlets for the product and the gas stream, wherein a vertically placed shaft (rotor) is rotating at high speed, which is mounted with a stack of cutting and impacting devices, for example blades, discs, plates, etc. The inner walls of the stator can be lined with corrugated plates in order to increase the grinding efficiency by additional friction and shear forces.

[0097] The rotor is usually rotating at a tip speed of about 20 m / s or more, more preferably about 35 m / s or more, even more preferably about 50 m / s or more. Usually, the speed is about 250 m / s or less, preferably about 150 m / s or less. A suitable speed is for example about 75 m / s. Usually, the tip speed is about 80 m / s or more, preferably about 110 m / s or more.

[0098] The grinder may generate a significant amount of heat. In addition, the incoming wet concentrated blood mixture may be at a temperature above room temperature. If useful, the gas stream can be heated, for example, by direct heating in a gas burner (which also results in a lower oxygen level, which reduces the ignition risk), or indirectly by heat exchange with steam or hot oil. The gas stream can also be superheated steam.

[0099] The air turbulence mill comprises one or more inlets for air streams. One or more of these air streams may be heated. Where one air stream is heated, it is preferably heated to a temperature of about 50° C. or higher.

[0100] Air flow can be introduced in various ways. Typically, the primary airflow is introduced at the bottom of an air turbulence mill. This inlet can be the same as the wet product inlet. In this case, the airflow is typically used to transport the product. A secondary airflow can be used to influence the mill's grinding and flow behavior. Especially if the product is not easily transported by the airflow, it can be introduced directly into the mill via a screw or pump.

[0101] To maintain high digestibility of the blood meal, the average residence time in the air turbulence mill is preferably short, for example, less than 10 seconds, preferably less than 5 seconds, more preferably less than 2 seconds, and even more preferably less than 1 second. A short average residence time of the material while it is drying in the mill allows for efficient drying while only a relatively small increase in the temperature of the coagulated blood material is observed. Where a classifier is used, the average residence time will be longer, but the time any powder actually spends in the mill is preferably kept below 10 seconds, even more preferably below 5 seconds.

[0102] Preferably, the temperature of the blood meal exiting the air turbulence mill is in the temperature range of between about 30°C and 90°C, more preferably between about 40°C and 80°C, even more preferably between about 45°C and 75°C.

[0103] The air stream leaves the air turbulence mill together with the dried product and optionally passes through a classifier. The dried product is separated from the air stream in the form of small particles, usually in one or more cyclones, preferably in one or two cyclones, or by means of a bag filter or a combination of both.

[0104] The resulting powder leaving the cyclone can be further classified, for example on a horizontal screen, to separate out oversized particles and / or remove dust. In addition, different grades of blood meal can be produced, having smaller and larger particle sizes.

[0105] The sieve oversize (oversized particles and / or dust) is preferably reintroduced into the feed for further processing in the air turbulent mill. The mixing of the oversize with the wet feed (also referred to as "recirculation") can improve the feed operation as well as the overall efficiency of drying and grinding. As mentioned above, the oversize can be mixed with a concentrated waste stream, which is obtained by increasing the solids content of, for example, blood water, and then mixed with the initial blood stream.

[0106] Depending on the feed to the air turbulent mill, it is useful to allow a substantial recirculation, for example 40-80 wt% of the resulting dry product is recirculated into the feed to increase the solids content in the feed while improving the overall properties of the product.

[0107] Thus, more generally, it is preferred to recirculate blood powder into the stream comprising the raw or coagulated blood that is provided to the air turbulent mill. The amount of recirculation can depend on the solids content of the stream supplied to the air turbulent mill. Typically, the amount of recirculated material is 1 wt% to 90 wt% (dry material), preferably 2-80 wt%. If only substandard material is to be recirculated, it is preferred to use a low recirculation value. To substantially increase the solids content (for example more than 5%), it is preferred to have a recirculation ratio of 5-90 wt%, more preferably 10-80 wt%.

[0108] In a preferred embodiment, if the solids content of the stream supplied to the air turbulent mill (without recirculation) is about 20 wt% or more, preferably 30 wt% or more, the amount of recirculated material is preferably such that the supply to the air turbulent mill will be about 40 wt% solids content or more. Thus, for example, if the supply stream contains about 20 wt% solids, a recirculation amount of about 40 wt% to about 90 wt% is suitable, and if the stream contains about 30 wt% solids, a recirculation amount of between about 10 wt% and about 70 wt% is suitable.

[0109] The amount is given in wt% of dry product, recirculated into the supply stream. The recirculation ratio can also be given based on the solids content in the supply stream (before recirculation). In a stream of about 20 wt% solids, the recirculation can be about 200-400%, preferably 200-300%, while in a supply of about 30 wt% solids, the recirculation ratio can be between about 50% and 200%.

[0110] Preferably, the classification is performed on a sieve (or other classification device) having a cut-off of 1 mm or less, preferably 800 pm or less. For example, the classification can be performed on a sieve having a cut-off of 300 pm, 500 pm or 900 pm.

[0111] Furthermore, the air flow entering the air turbulence mill can be adjusted to influence the residence time and / or particle size. For example, the air flow directly affects the residence time within the chamber and the contact time with the grinding equipment; higher air flow rates result in shorter residence times and, consequently, larger particles; conversely, lower air flow rates result in smaller particles. Particle size is further influenced by the presence of a classifier and / or adequate impact and cutting devices, as well as an adequate surface profile of the internal wall. A skilled artisan will be able to balance the air turbulence mill to provide the desired particle size.

[0112] Blood meal produced

[0113] The blood meal material is also used as a dry product (ie, blood meal) having a moisture content of about 15 wt % or less, preferably about 10 wt % or less.

[0114] The material preferably contains less than 8% moisture.Most preferably, the dried material has a moisture content of 5 to 7 wt%.

[0115] Blood meals according to the present invention typically comprise from about 85 wt% to about 98 wt% protein on a dry weight basis.

[0116] Advantageously, blood meal produced according to the methods of the present invention can provide a valuable source of protein and / or amino acids in animal feed. For example, blood meal can provide a source of one or more of the following amino acids: methionine, cysteine, lysine, threonine, arginine, isoleucine, leucine, valine, histidine, phenylalanine, glycine, serine, proline, alanine, aspartic acid, tyrosine, tryptophan, and glutamic acid. The high digestibility makes this product more effective as a feed additive than prior art clotted blood meal.

[0117] The ileal digestibility is about 85% or higher, preferably about 87% or higher, even more preferably about 90% or higher.

[0118] The pepsin digestibility of all bloodmeals as determined by ISO 6655 (August 1997) was relatively high (>95%) and therefore this analytical method was not able to adequately differentiate between different bloodmeal quality grades. Ileal digestibility was more sensitive to the method.

[0119] The blood meal according to the invention showed high digestibility in in vivo experiments with cecally removed roosters and trout.

[0120] Furthermore, the bioavailability of lysine in the product obtained by the process of the present invention is also very high.

[0121] The clotted (or coagulated) blood meal product obtained by the method of the present invention is believed to be a novel product. Like other dried, fully coagulated blood products, the clotted blood meal exhibited substantial settling of the product within 24 hours of dispersion in water, whereas the spray-dried, non-coagulated product remained largely dispersed during this time period and, therefore, exhibited no settling behavior during this time period.

[0122] The present invention provides a coagulated blood meal product having an average particle size (d50) of between 20 μm and 0.7 mm and a d90 of less than 1 mm as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, and having an ileal digestibility of about 85% or more, preferably about 87% or more, and even more preferably about 90% or more.

[0123] The coagulated blood meal product preferably has a bioavailable lysine content of about 92% or greater, and even more preferably about 94% or greater, relative to the total lysine content.

[0124] The apparent digestibility (ADC) of the trout of the coagulated blood meal product relative to crude protein is preferably about 80% or greater, even more preferably about 85% or greater, and most preferably about 87% or greater.

[0125] Blood meal contains at least 17 amino acids, preferably at least 18 amino acids, such as lysine.

[0126] Preferably, the amount of lysine is about 7 wt% or more relative to the total protein content.

[0127] Blood meal is rich in heme iron, which is the most biologically available form of iron.

[0128] The powder properties described below relate to all products obtainable by the process of the present invention and therefore apply to blood powder obtained from coagulated blood, anticoagulated blood and / or a mixture of both. They also apply to the hemoglobin fraction of whole blood and / or the plasma fraction of whole blood and / or any mixture of a hemoglobin fraction, a plasma fraction, coagulated blood and anticoagulated blood.

[0129] The dried and ground material exiting the air turbulence mill is typically in the form of particles of which greater than about 99% by weight are smaller than a few millimeters, e.g., smaller than about 2 mm, preferably smaller than 1 mm. Typically, greater than about 95% by weight are larger than about 8 μm, so as to provide a free-flowing powder that can be easily handled and further processed into, for example, formulated pet foods and animal feeds.

[0130] In a preferred embodiment, the average particle size of the classified product (defined as d50; the volume fraction of particles is 50% larger and 50% smaller), as measured on a Beckman Coulter particle size analyzer using standard software, is between about 20 μm and about 0.7 mm, preferably between about 20 μm and about 500 μm, more preferably about 40 μm or higher, and more preferably about 50 μm to about 300 μm. For example, the average particle size is about 75 μm or about 150 μm.

[0131] d90 is preferably less than about 1 mm, more preferably less than about 0.7 mm. d10 is preferably greater than about 10 μm, more preferably greater than about 15 μm.

[0132] These sizes are very advantageous. Steam-condensed blood dried in conventional disc or drum dryers or blood dried by freeze drying has a coarse, non-uniform particle size distribution at the dryer outlet, with a significant number of particles larger than 1.8 mm and often larger than 2 mm or higher, requiring further grinding and screening equipment, resulting in additional floor space requirements and additional dust emission issues. This makes such equipment a less attractive process unit.

[0133] The particle size distribution of the blood meal of the present invention is relatively uniform. For example, d90 divided by d10 is about 12 or less, preferably about 10 or less, and d90 is about 1 mm or less.

[0134] The blood meal obtained with the process according to the invention is in the form of a powder, preferably with powder properties such that the powder has good flow properties, packaging properties and good dosing properties for formulating pet food and animal feed.

[0135] The powder according to the invention has a Hausner ratio (tap density divided by poured bulk density) of about 1.06 to 1.18, ie preferably below about 1.2, which is considered to be an indication of good flowability.

[0136] In a preferred embodiment of the present invention, the blood meal has a poured (bulk) density of about 0.35 g / cm 3 or higher, more preferably about 0.45 g / cm 3 or higher, even more preferably about 0.5 g / cm 3 Or higher. Typically, the poured density will be about 0.7 g / cm 3 or lower, such as about 0.6 g / cm 3 or lower.

[0137] In another preferred embodiment of the present invention, the tapped bulk density of the blood meal is about 0.4 g / cm 3or higher, more preferably about 0.5 g / cm 3 or higher, even more preferably 0.55 g / cm 3 Or higher. Typically, the tapped bulk density will be about 0.75 g / cm 3 or lower, such as 0.65g / cm 3 or lower.

[0138] In another embodiment, the blood meal may be pelletized to increase its density to optimize volume and shipping costs.

[0139] Furthermore, the blood meal obtained according to the method described herein has a significantly milder odor compared to conventional pan-dried blood meal. The high turbulence, very short residence time, lack of contact with hot surfaces (unlike in pan dryers), and lack of deposits on the inner walls (unlike in spray dryers and in the pipes of ring dryers) avoid the formation of burnt particles and odorous compounds.

[0140] Another advantage of drying and grinding in an air turbulence mill is that the material is lighter and more uniform in color than conventionally dried material. In particular, black specks are virtually absent.

[0141] Preferably, blood meals according to the present invention contain no detectable Salmonella in standard assays.

[0142] Antioxidants and / or anti-caking agents may be incorporated into the blood meal to improve its oxidative stability and its flowability, respectively.

[0143] In a preferred embodiment, the antioxidant is added in liquid or solid form and mixed into the concentrated blood mixture before the turbulent mill in order to have a uniform incorporation and avoid undesirable specks and agglomerations if such incorporation is performed on the finished powder. When using dry blood meal for backmixing and thus mixing with a dry product that already contains antioxidants, the amount of antioxidant added to the fresh wet stream is adjusted accordingly.

[0144] Some amino acids can be added to the blood meal before or after drying. In particular, it is useful to add isoleucine, cysteine, and / or methionine, or digestible proteins containing relatively high amounts of these amino acids, since these amino acids are relatively low in blood meal. Typically, the amount added will be about 20 wt% or less, preferably about 10 wt% or less.

[0145] Blood meal can be packed in small bags, large bags or other large containers. Dried blood meal can be packed and shipped in any large container, large bag or other container.

[0146] Blood meal can be used as a feed or feed supplement, for example in pet food and / or aquaculture feed. The material can be used in powder form or converted to larger dosage units using conventional processing techniques in the form of granules, flakes, etc. Blood meal can be used as a carrier for other ingredients and / or as a bulking agent.

[0147] When used in the preparation of feed, the blood meal produced according to the present invention can be combined with one or more of the following: a nutritionally acceptable carrier or bulking agent, a nutritionally acceptable diluent, a nutritionally acceptable excipient, a nutritionally acceptable adjuvant, or a nutritionally active ingredient. The blood meal itself can serve as a carrier or bulking agent for other functional ingredients, such as flavoring agents, mouthfeel agents, and attractants.

[0148] The method of the present invention can be easily applied to conventional plants for processing at least partially coagulated blood, anticoagulated blood, fractions thereof, and / or mixtures thereof, since an air turbulence mill with an optional classifier, cyclone separator, and air supply occupies significantly less space than a conventional disk dryer or other conventional dryers with auxiliary equipment. Therefore, the present invention also relates to a method for converting a blood meal plant by replacing a conventional drying plant with an air turbulence mill and a cyclone separator with auxiliary equipment, or by adding such an air turbulence mill after a conventional drying plant and operating the conventional plant to a higher residual moisture content and completing the drying in the air turbulence mill.

[0149] Measurement method

[0150] The following methods were used in the examples and are suitable as methods for measuring the parameters described in the specification and claims:

[0151] Water by weight (wt%): The damp material was dried overnight in a vacuum oven under reduced pressure with a desiccant. The material was weighed before and after the drying step, and the amount of water was calculated using the initial measured weight as 100% and assuming that all volatile material was water.

[0152] Solids content is defined as the solids remaining after removing the water as described for the moisture wt%.

[0153] Precipitation test: Add 3 grams of blood meal to 100 ml of water in a clear beaker at room temperature and stir for 1 minute. Let the beaker sit for 24 hours. Afterward, take a photograph and determine whether a clear precipitate is visible or whether the liquid has uniformly darkened.

[0154] Pepsin digestibility was measured according to ISO 6655 (August 1997) using a pepsin concentration of 0.02% in hydrochloric acid as described.

[0155] Ileal digestibility (also called Boisen digestibility) was measured according to the method described by S. Boisen, "Prediction of apparent ileal digestibility of protein and amino acids in swine feeds by in vitro analysis," Animal Feed Science Technology, 51, pp. 29-43 (1995) and further described in "In vitro analysis for determining the standardized ileal digestibility of protein and amino acids in actual batches of swine feeds and diets," Livestock Science, 309: pp. 182-185 (2007).

[0156] Particle size distribution was measured by laser diffraction on a Beckman Coulter Particle Size Analyzer – Dry Powder System using the manufacturer's standard software. Results are reported as d10, d50, d90, etc., which are related to volume fraction.

[0157] The poured and tapped densities were measured on a Jolting Volumeter Type STAV II from Engelsmann. According to the manufacturer's manual, this device is used to determine the volume before and after tamping, the compacted and tapped density according to the European Pharmacopoeia, DIN ISO 787 Part 11, ISO 3953, ISO 8967 and ASTM B 527-93.

[0158] Lysine is measured according to ISO 5510:1984, where both bioavailable lysine and total lysine are determined to determine the ratio between the two.

[0159] Apparent digestibility (ADC) experiments were conducted on rainbow trout using a triplicate model test (3 boxes of 15 trout). The water in the boxes was adjusted to 17°C + / - 0.5°C, the oxygen content at the inlet was controlled and maintained at 9.5 ppm, nitrogen was removed by a biofilter, and the fish were exposed to a 12-hour photoperiod. The fish were fed ad libitum twice a day. The feed was prepared by mixing 20% ​​of the test ingredient with 80% of a reference feed (which contained fish meal (75%), starch, wheat gluten, a premix of minerals and vitamins, and yttrium as an inert marker); the mixture was extruded into 4 mm pellets using a twin-screw Clextral extruder, and fish oil was incorporated into the pellets under vacuum. The average starting weight of the trout was between 100 and 120 grams. The boxes were equipped with an automatic feces collection system. Feces were collected only after one week to allow the fish to acclimate to their box environment and their feed to stabilize ADC. Feces were collected once a day in the morning before eating, frozen, and then freeze-dried before analysis. ADC was calculated using an indirect method according to the formula of Maynard and Loosli (Animal Nutrition, 6th edition, McGraw Hill, New-York, 1969).

[0160] Cecoectomized Rooster Method: In vivo digestibility of crude protein, dry matter, and amino acids is determined by a specialized laboratory using a duplicate model. Two groups of three cecoectomized roosters are fasted for 24 hours and then force-fed with a precise amount of a formulated diet containing the dried blood sample to be analyzed. Feces, including endogenous losses, are collected within 48 hours. The feces are cleaned to remove foreign matter such as feathers and then further frozen, freeze-dried, and homogenized. Digestibility is then calculated by comparing the crude protein, dry matter, and total amino acid content measured in the dried blood sample with that in the freeze-dried feces, after correction for endogenous losses.

[0161] Further modifications besides those described above may be made to the materials and methods described herein without departing from the spirit and scope of the present invention.

[0162] Therefore, although certain embodiments have been described, the following is by way of example only, and is not intended to limit the scope of the invention.

[0163] Example

[0164] Raw partially coagulated blood is obtained from slaughterhouses. It contains >90% poultry blood. The solids content is approximately 10%.

[0165] The raw partially coagulated blood is further coagulated with fresh steam (about 150 kg steam per ton of partially coagulated blood), and the clotted blood is concentrated in a centrifuge to obtain a clotted blood mixture with a solid content of about 40%.

[0166] The clotted blood mixture was placed in an air turbulence mill ( The concentrated blood mixture was dried in an Ultra Rotor III a) with a feed rate of 200 kg / h. The clotted blood mixture was dried and ground in multiple runs. The air turbulence mill was operated at a temperature of 160° C. using an inlet gas (air). The gas volume was approximately 15 to 30 m 3 / hr*kg. The tip speed of the rotor is between 80 and 90 m / s.

[0167] The average residence time of the product was estimated to be less than about 1 second. During the drying and grinding process, the blood meal product was estimated to have not reached temperatures above about 80°C, as the air temperature at the outlet of the air turbulence mill was about 90°C. The product was sieved using a 300 μm sieve, and the smaller particle size fraction was further characterized as described below. In one test, the larger particle size fraction (about 2-5 wt%) was fed back into the feed of the air turbulence mill; this run stabilized the operation.

[0168] The product thus obtained was compared with conventionally dried (in a disk dryer) blood meal; it was also compared with spray-dried blood meal in a conventional ring dryer. It must be recognized that the spray-dried material is made from anticoagulated blood; otherwise the spray nozzle would clog.

[0169] Many characteristics are compared. It can be concluded from the following table:

[0170] - The ileal (Boisen) digestibility of the product produced according to the method of the invention is higher compared to conventional dried clotted blood products.

[0171] - The in vivo digestibility of the product according to the invention in cecally removed roosters was much better than that of conventional dried clotted products and was essentially the same as that of spray-dried blood meal.

[0172] - The apparent digestibility coefficient (ADC) of trout based on crude protein of the product prepared according to the process of the invention is much better compared to conventional dried coagulated products.

[0173] - Also compared to the spray-dried product, the bioavailable lysine, an important indicator of the bioavailable amino acids, was significantly higher in the product according to the invention.

[0174] The product obtained with the process of the present invention can have a particle size distribution as good as that obtained by spray drying. A narrower particle size distribution can be achieved with the process according to the present invention. However, it should be noted that by allowing fractionation at, for example, 1 mm instead of 300 μm, a coarser material can be easily obtained.

[0175] - Sedimentation tests showed that blood meal from clotted blood showed clear sedimentation, unlike spray-dried blood meal.

[0176] In addition (not shown in the table), the color of the product prepared according to the method of the present invention is lighter and more uniform than that of conventional dried clotted blood products. Moreover, the product obtained by the method of the present invention has a significantly milder odor (neutral to mild odor) than that of conventional dried clotted blood products.

[0177] The process of the invention allows to obtain very high quality blood meal, even with a bioavailable lysine content that is significantly higher than the best quality blood meal to date (spray-dried blood meal).

[0178] The method using an air turbulence mill is significantly cheaper and simpler to operate than the spray drying method, and can achieve a quality substantially equivalent to that of a spray-dried product, which is very advantageous.

[0179]

Claims

1. A method for preparing blood meal, comprising the following steps: (i) providing an aqueous mixture comprising raw blood, preferably having a solids content of about 5 wt% to about 18 wt%, and (ii) increasing the solids content of the mixture to obtain a mixture having a solids content of about 20 wt% or more, preferably about 20-80 wt% and (iii) simultaneously drying and grinding the resulting mixture in an air turbulence mill to obtain a blood meal having an average particle size (d50) of 20 μm to 0.7 mm, a d90 of less than 1 mm, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, and an ileal digestibility of about 85% or more, preferably about 87% or more, more preferably about 90% or more.

2. The method according to claim 1 , wherein the aqueous mixture of step (i) is subjected to a coagulation step, preferably using live steam, and wherein an increased solids content is subsequently obtained by removing a portion of the water, thereby obtaining a coagulated blood mixture with a solids content of 30-70 wt %, preferably 40-60 wt %.

3. The method of claim 1 , wherein the aqueous mixture comprising raw blood has a solids content of less than 18 wt % or less than 12 wt %, wherein the mixture is optionally homogenized and the solids content is increased in step (ii) to a solids content of about 30 wt % or more by removing water and / or by adding dry blood powder and / or concentrated blood, preferably at least a portion of the increase in solids content is achieved by back-mixing dry blood powder into the mixture.

4. The process of claim 3, wherein the amount of back-mixed blood meal is between about 2 wt% and about 90 wt%, wherein the amount is given as a wt% of the dry product back-mixed into the feed stream supplied to the air turbulence mill, preferably between about 10 wt% and about 80 wt%.

5. The process according to any one of the preceding claims, wherein the solids content in step (ii) is increased by about 10 wt% or more, preferably about 20 wt% or more.

6. A method according to any one of the preceding claims, wherein the mixture comprising raw blood is treated at a sufficiently high temperature and for a sufficient time to achieve pasteurisation or sterilisation of the mixture before supplying the mixture to the air turbulence mill.

7. A process according to claim 6, wherein the pasteurisation conditions are such as to impart a temperature / time treatment at least equal to 85°C, or preferably 90°C, even more preferably about 95°C, for 2 minutes at 10 wt% solids.

8. The method according to any one of claims 6 or 7, wherein the mixture comprising the raw blood is treated at a sufficiently high temperature and for a sufficiently long time to achieve the thermal death time of Salmonella and Clostridium perfringens.

9. The method according to any one of the preceding claims, wherein drying and grinding are carried out simultaneously at a temperature such that the material being dried and ground is maintained at a temperature of about 90°C or less, preferably about 80°C or less and more preferably below 60°C.

10. The method according to any one of the preceding claims, wherein the air turbulence mill comprises a chamber with appropriate inlets and outlets for product and gas streams, wherein a rotating member is mounted with a stack of impact devices, the rotating member being rotatable at high speed, and wherein preferably the inner wall of the stator is lined with impact members, wherein the rotating member rotates at a tip speed of 35-250 m / s.

11. A method according to any one of the preceding claims, wherein the air turbulence mill comprises an internal or external classifying device which allows for the recirculation of coarse material into the mill.

12. The process according to any one of the preceding claims, wherein the air turbulence mill is operated at a temperature between about 20° C. and about 500° C., preferably at a temperature between about 20° C. and about 450° C., with a gas stream, preferably an air stream with an optionally reduced oxygen content, and wherein the gas flow rate is about 5 m3 / kg of feed. 3 / hr to about 50m 3 / hr, the flow rate can be adjusted to affect the particle size of the dried blood meal, and the residence time is less than 10 seconds.

13. Coagulated blood meal having an average particle size (d50) of between 20 μm and 0.7 mm, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, a d90 of less than 1 mm, and an ileal digestibility of 85% or more, preferably about 87% or more, even more preferably about 90% or more, and a moisture content of about 10 wt% or less, preferably 5-8 wt%.

14. A blood meal according to claim 13 or obtained by the method according to any one of claims 1 to 12, wherein the blood meal has a bioavailable lysine content of about 92% or more, preferably about 94% or more.

15. A blood meal according to any one of claims 13 to 14 or obtained by the process according to any one of claims 1 to 12, wherein the blood meal has an apparent digestibility coefficient in trout of about 80% or more, preferably about 85% or more, more preferably about 87% or more, based on crude protein.

16. A blood meal according to any one of claims 13 to 15 or obtained by the method of any one of claims 1 to 12, wherein the blood meal has an average particle size (d50) of between about 20 μm and about 0.5 mm, preferably between about 50 μm and about 300 μm, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer.

17. A blood meal according to any one of claims 13 to 16 or obtained by the method of any one of claims 1 to 12, wherein the blood meal has a d90 particle size of about 0.7 mm or less as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer, and / or wherein the blood meal has a d10 particle size of about 10 μm or more, preferably about 15 μm or more, as measured by laser diffraction using a dry powder Beckman Coulter particle size analyzer.

18. Use of the blood meal obtained according to any one of claims 1 to 12 or according to any one of claims 13 to 17 as feed and / or feed additive, for example in pet food or for aquaculture feed; or in cosmetics; as a carrier for mouthfeel agents in pet food and feed and / or as a protein extender.

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