WO2005082158A1

WO2005082158A1 - A method of producing an amino acid enriched animal feed

Info

Publication number: WO2005082158A1
Application number: PCT/IB2004/004181
Authority: WO
Inventors: Robert Fletcher Kenyon; David George Stedman
Original assignee: Forum Products Limited
Priority date: 2004-01-29
Filing date: 2004-12-13
Publication date: 2005-09-09

Abstract

A method of producing an amino acid enriched animal feed includes combining an amino acid, a base selected from aqueous ammonia and the oxides, hydroxides and carbonates of alkali or alkaline earth metals and mixtures thereof, optionally an inorganic acid, optionally a fatty acid and water in a first reaction zone over a first period of 2 - 60 seconds to produce a reaction mixture in the first reaction zone. The reaction mixture is then transferred from the first reaction zone to a second reaction zone, over a second period of 2 - 60 seconds. Heat generated by reaction between the reactants in the second reaction zone is allowed to drive off sufficient water to produce a product mixture in the form of an animal feed containing less than about 15%(m/m) water.

Description

A METHOD OF PRODUCING AN AMINO ACID ENRICHED ANIMAL FEED

THIS INVENTION relates to a method for the production of an amino acid enriched animal feed and to an amino acid enriched animal feed produced in accordance with the method.

The processes of fermentation and digestion which take place in the rumen of ruminant animals are beneficial under natural feeding conditions. However, for optimum production of meat and/or milk, modern husbandry methods require that animals such as cattle should be fed a proportion of their dietary requirements in a form that undergoes minimal alteration or degradation in the rumen. At the same time, these nutrients should not interfere with the normal processes of rumen fermentation.

It is known that, in order to maximize milk production or weight gain, a cow should be fed sufficient quantities of fat. However it is also known that if a mature cow is fed more than about 500 g of fat per day, the normal processes of rumen fermentation may be adversely affected.

Additionally it is known that triglycerides and free fatty acids can physically coat fibrous or cellulose-containing material in the rumen, thereby preventing the material from being broken down by the rumen bacteria. This can have an adverse effect on the total digestibility of the diet and is reflected in reduced yields of milk and/or butterfat. Furthermore, certain fatty acids, and particularly some unsaturated fatty acids, are known to be toxic to certain rumen bacteria and this too can have adverse effects on the total digestibility of the diet. The production of milk containing unsaturated fatty acid may also be reduced by the presence of unsaturated fats in the diet. It is also difficult to produce milk containing a high proportion of unsaturated fats from hydrogenated materials. This requires that, ideally, the fat be protected from normal rumen processes.

However it is also known that a proportion of the amino acids fed to ruminants is broken down before exiting the rumen. This results in a loss of nutrients. It is therefore desirable for a product containing essential amino acids and fats to pass through the rumen, but to be protected from the normal rumen processes.

There are many methods of protecting fats and proteins from the effects of rumen fermentation so that they are not digested until they reach the abomasum. Many of these methods depend partially upon protecting such fats and/or other nutrients (such as proteins, minerals, or essential vitamins) in a coating that resists the fermentation processes of the rumen. Alternatively, the protection may be brought about by the formation of a water-insoluble salt of a fatty acid. Several prior art procedures known to the Applicant describe the incorporation of insoluble fatty acid salts in ruminant feed as a means of increasing the fat content of the feed without deleteriously affecting the ruminant digestion cycle. A feed additive, such as a fatty acid calcium salt, functions as a rumen bypass product, and is subsequently metabolized in the abomasum or small intestine of the ruminant.

It is also well known within the animal feed industry that energy is one of the major costs incurred during the manufacture of animal feed. It has also been found that it is difficult to make an animal feed in solid form which is completely homogeneous if only one or two materials make up the bulk of the feed and minor ingredients such as anti-oxidants, flavourants, trace minerals and amino acids comprise only a small fraction of the product.

In an ideal situation, most of the components of an animal feed would be completely mixed before the drying stage. However it would be advantageous if drying could be achieved by chemical means, for example through exothermic reactions, typically with a basic metal or ammonium salts. This would allow many of the components to be utilized in their raw or liquid form and then dried whilst the mixture is completely homogeneous. This would result in products forming in-situ, whilst located within a matrix, and drying within the same matrix.

The Applicant is aware of prior art feedstuffs which are prepared by combining long chain fatty acids with bases such as the oxides, hydroxides and carbonates of alkali and alkaline earth metals. In some cases, the reactants include amino acids so that the feedstuff produced contains the salt of the fatty acid and the amino acid. However, in all of these cases, the amount of amino acid in the feedstuff is substantially less than the amount of the fatty acid. Furthermore, the amount of amino acid in the feedstuff is, in all cases, less than 20% and, in most cases, substantially less than 20%. Examples of such prior art feedstuffs are disclosed in US 4,642,317, 4,826,694, US 4,853,233, US 4,909,138, US 5,234,701 , US 5,382,678, US 5,391 ,787, US 5,391 ,788, US 5,425,963, US 5,456,927, US 5,585,134, US 5,670,191 and US 5,849,348.

However, these are two important differences between these prior art methods and the present invention. The first is that the method of the present invention allows the production of animal feedstuffs which contain substantially more amino acid (up to 80% or more) than the prior art processes. None of the prior art processes is able to produce a product which contains large amounts of amino acid. The second important difference between the prior art methods and the method of the invention is that the method of the invention involves the rapid combination of starting materials in a first reaction zone, in a mixing time which is measured in seconds, and the rapid transfer of the resulting reaction mixture to a second reaction zone, in a transfer time which is also measured in seconds, where the heat of reaction is allowed to drive off most of the water so that a granular product is produced.

According to a first aspect of the invention there is provided a method of producing an amino acid enriched animal feed, the method including the steps of combining and mixing reactants which include at least one amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally at least one fatty acid and water in a first reaction zone, the combining and mixing step being carried out over a first period of 2 - 60 seconds to produce a reaction mixture in the first reaction zone; transferring the reaction mixture at the end of the first period from the first reaction zone to a second reaction zone, the transferring step being carried out over a second period of 2 - 60 seconds; and allowing heat generated by reaction between at least some of the reactants in the second reaction zone to drive off sufficient water to produce a product mixture in the form of an animal feed containing less than about 15%(m/m) water.

The animal feed may preferably contain about less than 10% (m/m) water. More preferably, it will contain 5% or less water.

In this specification, the term percentage (m/m) refers to a mass per mass percentage. The product mixture is generally a dry, free flowing material.

The first period will preferably be between about 10 and 30 seconds. The second period will preferably be between about 2 and 15 seconds.

The reactants may optionally include one or more additional components selected from hydrolysed casein, di-peptides, tri-peptides, tetra-peptides disintegrants and combinations thereof. The disintegrant(s) may be selected from sodium starch, sodium glycollate and the like.

The alkali and alkaline earth metals may be selected from Li, Na, K, Ca and Mg.

The base is preferably selected from calcium oxide, calcium hydroxide, magnesium oxide, magnesium carbonate, burnt dolomite (magnesium/calcium oxides), dolomite lime (magnesium/calcium carbonate), sodium carbonate and mixtures thereof.

The fatty acid may be in a form selected from the free acid, a salt of the free acid and mixtures thereof. The fatty acid will preferably be a Cι - C₂o edible higher fatty acid or fatty acid distillate but is not limited to this range.

The fatty acid may thus be selected from Cι₄ - C₂o edible fatty acids and C₁₄ - C₂₀ edible fatty acid distillate. The edible fatty acid may be palm oil fatty acid (POFA) and the edible fatty acid distillate may be palm oil fatty acid distillate (PFAD).

The at least one amino acid may be selected from lysine, methionine, 2- hydroxy-4(mercaptomethyl)butanoic acid (also referred to as methionine hydroxy analogue free acid or MHA), threonine, proline, hydroxyproline, omithine, arginine and mixtures thereof.

The at least one amino acid may be provided in the form of an aqueous solution.

The aqueous solution of the amino acid may have a concentration of about 25 - 98% and preferably about 25 - 98% in the case of lysine and about 60- 98% in the case of methionine hydroxy analogue free acid.

The inorganic acid may be selected from phosphoric acid, sulphuric acid and mixtures thereof.

The amount of reactants may be selected so that the animal feed contains between about 0% and 72% of the fatty acid and between about 5% and 75% of the amino acid. Thus, in some embodiments of the invention the animal feed will contain no fatty acid. This is one of the main differences over prior art method which do not work if a large amount of fatty acid (which is substantially more than the amount of amino acid) is not present. Preferably, the amounts of reactants will be selected so that the animal feed contains between about 0% and 50% of the fatty acid and, more preferably, between about 0% and 25%. The amounts of reactants may be selected so that the animal feed contains between about 10% and 45% of the amino acid and preferably between about 12% and 40%. In preferred embodiments of the invention, the animal feedstuff will contain more than 20% and preferably more than 25% of the amino acid.

The amounts of reactants may be selected so that the animal feed contains the fatty acid, lysine, methionine, phosphorous, calcium, sodium, magnesium, and free moisture in the following amounts:

Fatty Acid 0 85% Lysine 0 80% Methionine 0 75% Phosphorous 0 20% Calcium 0 25% Sodium 0 15% Magnesium 0 15% Free moisture 0 10%

In preferred embodiments, the amounts of reactants will be selected so that the animal feed contains:

Fatty Acid 5 60% Lysine 0 50% Methionine 0 35% Phosphorous 0 15% Calcium 0 20% Sodium 0 5% Magnesium 0 5% Free moisture 2 10%

The reactants may include lysine and methionine and the mass ratio between the lysine and methionine in the animal feed will preferably be, but is not limited to, between about 1 :5 and 5:1.

The molar ratio between the total amount of base and the total amount of acid may be between about 0,70 : 1 ,00 and 1 ,30 : 1 ,00 and is preferably between about 0,95 : 1 ,00 and 1 ,10 : 1 ,00. However, where combinations of the amino acids (e.g. lysine and

methionine) are not required, or where the product may contain a fatty acid or

phosphorous as well (or a combination of a fatty acid, amino acid and

phosphorous), the feed may contain nutrients in the following ranges:

Fatty Acid 0 - 80%

Lysine 0 - 60%

Methionine 0 - 75%

Phosphorous 0 - 1 5%

Calcium 8 - 20%

The water present during the combining and mixing step will typically be the sum of the water of solution of the liquid components, although more water may be added if necessary. Water is also produced as one of the reaction products.

The total amount of water present during the combining and mixing step may be between about 2 and 45% of the total mass of the reactants and is preferably between about 2 and 35% of the total mass.

The dry raw materials may be individually combined and mixed in the first step. Optionally the dry raw materials may be pre-mixed prior to the first step. The basic metal salt may be mixed in with the other dry materials, but is preferably added separately. Similarly, the liquid components may be individually combined and mixed in the first step or they may be rapidly blended prior to the first step. If a fatty acid which is solid at room temperatures is used, it is preferably melted prior to use.

It is also possible to use the fatty acid as a solid. In this case, the aqueous component from the amino and inorganic acids helps fluidise the mixture. The rapid aggressive mixing used in the process breaks up the fatty acid and allows attack by the base salt. The smaller particles of fatty acid are readily attacked by the base salts. This, in turn, raises the temperature of the reacting magma, melting the remaining solid fatty acid.

In a preferred embodiment of the invention, the liquid reactants with the exception of the fatty acid are charged individually into a high-speed mixing unit. A blend of solid reactants excluding the basic salt or salts is then added. The basic salts and the fatty acid are added simultaneously as the last components.

However in another embodiment the liquid reactants are rapidly pre- blended and then a mixture of the dry solid reactants is rapidly added to the blended liquid reactants. The resulting product is substantially identical to that made by the preferred route.

The rapid mixing followed by rapid discharge allows an exothermic reaction between the components to be initiated but allows the reaction magma to be transferred before any significant loss of liquid or solidification occurs. The reaction is completed in a second or further stage downstream during which rapid moisture loss and drying takes place. Optionally, the second stage may be agitated. This applies in respect of each embodiment of the invention described herein.

The exothermic reaction generally starts within approximately 10 seconds of the addition of the basic salts. The commencement of the exotherm is characterized by a fast rise in the temperature of the fluid accompanied by frothing and a rapid expansion in the volume of the reacting liquid. Typically the temperature

of the reaction mixture rises from about 20°C to about 110°C within about two

minutes of the addition of the basic salt. The maximum temperature reached by the

mixture is usually about 120°C.

The free moisture of the product is generally below 10%, and usually below 4%. The pH of a 10% (m/m) slurry in water is usually in the range 6 - 10.

The method may include the further steps of successively combining and mixing a plurality of batches of the reactants in the first reaction zone according to the method described above to produce successive batches of the reaction mixture and successively transferring each of the batches to the second reaction zone. There may be more than one second reaction zone.

The second reaction zone may be a receiving vessel and one or more batches of reaction mixture may be transferred into the same receiving vessel until the receiving vessel is full or contains a predetermined quantity of the reaction mixture. The receiving vessel may then be replaced with a second receiving vessel and further batches may be added to the second receiving vessel. This process may be continued until the initially used receiving vessels have been emptied so that they can be reused. It is an advantage of this embodiment of the invention that the reaction vessel and all of the receiving vessels can be kept within an enclosed area so that steam and fumes produced in the reaction can be extracted and dealt with by an appropriate disposal system.

In an example of this embodiment of the invention, a material dosing system, controlled by a programmable logic controller or similar suitable control unit, weighs out the reactants in sequence into a mixing vessel. The agitator in the mixing vessel starts immediately on receiving a signal that the first of the reactants has been dosed. Optionally an operator-controlled delay can be introduced between the opening of the dosing valves and the beginning of the agitation.

Thus the method may be one in which a material dosing system controlled by a programmable logic controller, weighs out the reactants into the first reaction zone.

In this embodiment of the invention, the number of batches is determined by the size of the initial mixing vessel, the swelled volume of reactants and magma, the receiver capacity and the rate of loss of volatile materials from the reacting magma. When the receiving vessel is full, further batches may be discharged into a fresh receiving vessel. Once the material in the first receiving

vessel is dry enough (i.e. typically having a water content of less than about 10% and

usually less than about 4 - 8%), the contents are discharged and the vessel is reused.

The contents of the first receiving vessel are generally discharged when the second

receiving vessel is full and the contents of the second vessel are discharged when the

first vessel is full. The discharged material is allowed to cool and optionally crushed

to allow heat to escape. The final product is then dressed according to size and packaged. If necessary, an additional drying step can be introduced.

It is possible to run the process so that one or more liquid or solid

components are pre-weighed and premixed prior to discharge into the first stage.

This facilitates rapid discharge into the mix, and permits the elevation of the

temperature of one or more components. The elevation of the initial temperature

helps with the removal of free moisture. The warming up of the liquid

components is typically, but not limited to, about 10 - 40°C above the ambient

temperature within the manufacturing area.

Preferably, the reaction vessels will be designed to have no sharp internal corners or edges. The vessels will also preferably be lined with an inert

material such as a layer of PTFE (polytetrafluoroethylene) or a similar material. The top of the mixing/reaction vessel will preferably be provided with an extraction system

for extracting steam and vapours. The inner lining material serves to reduce adhesion between the reactants, the product and the vessel to facilitate rapid discharge when the vessel is discharged.

According to a second aspect of the invention, there is provided a method of producing an amino acid enriched animal feed, the method including the steps of combining and mixing reactants which include at least one amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water in a first reaction zone to produce a reaction mixture in the first reaction zone; and continuously transferring the reaction mixture from the first reaction zone to a second reaction zone, the reactants being added to the first reaction zone in successive batches and the reaction mixture being continuously removed from the first reaction zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is between about 2 and 60 seconds; and allowing heat generated by reaction between at least some of the reactants in the second reaction zone to drive off sufficient water to produce a product mixture containing less than about 15% water.

Preferably the method will involve allowing heat generated to drive off sufficient water to produce a product mixture containing less than about 10% water. In some embodiments, the product will contain less than about 5% water, in other embodiments it will contain about 4 - 8%. The rate of removal of the reaction mixture from the first reaction zone will depend on the production capacity of the installation and may vary between about 10 and about 10000 kg per hour.

According to a third aspect of the invention, there is provided a continuous method of producing an amino acid enriched animal feed, the method including the steps of simultaneously feeding, into a first reaction zone, reactants comprising an amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water to produce a reaction mixture in the reaction zone; and transferring the reaction mixture from the first reaction zone to a second zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is sufficient to allow heat generated by reaction between the reactants in the first reaction zone to drive off at least some of the water and allowing heat generated by further reaction in the second zone to drive off sufficient water to produce a product mixture containing less than about 15% water, the rate of transfer being selected so that the residence time of the reaction mixture in the first reaction zone is between about 2 and 60 seconds.

The product will preferably contain less than about 10% water. The rate will preferably be selected so that the residence time of the reaction mixture in the first reaction zone is between about 2 and 30 seconds and, in the second reaction zone, between about 2 and 30 minutes.

According to a fourth aspect of the invention, there is provided a continuous method of making an amino enriched animal feed, the method including the steps of simultaneously feeding, into a first reaction zone, reactants comprising an aqueous solution of an amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and the alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water to produce a reaction mixture in the reaction zone; and transferring the reaction mixture from the first reaction zone to a second zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is between about 5 and 60 seconds and is sufficient to initiate reaction between at least some of the reactants but not sufficient to drive off any substantial amount of water from the reaction mixture and allowing heat generated by further reaction between at least some of the reactants in the second zone to drive off sufficient water to produce a product mixture containing less than about 15% water.

The time in the first zone will preferably be between about 10 and 20 seconds. The product will preferably contain less than about 10% water.

The rate of addition of the reactants will depend upon the production capacity of the plant in which the process is conducted. Production levels of 10 tons per hour can be achieved by the method of the invention.

The reaction mixture in the first reaction zone may be transferred to an endless moving belt so that the second reaction zone is formed by the belt. The reactants will then react whilst being carried on the belt. The length of the belt and the speed of the belt will be selected so that, when the material is discharged from the belt, the resulting product mixture contains the desired amount of water. The belt will preferably be enclosed so that steam and fumes produced by reaction between the acid and the calcium salt can be extracted and dealt with by an appropriate disposal system as described above.

Preferably, at the point of discharge from the belt, the material will be passed through a rotating cutter, to reduce the particle size and to release trapped steam and gases in the product. The product will then be transported on a conveyor or suitable handling device for further processing as required, for example for granulation, drying, cooling, dressing or bagging.

There are several important advantages associated with this embodiment of the invention. Because there is minimal mixing of the product after the initial feeding and mixing stage, energy requirements of the process are reduced. Furthermore, when the product passes through the plastic stage, no mechanical agitation takes place. There is therefore no contact between a mixing device and the thickening product and no build-up or aggregation of material in the mixing vessel or on the agitator. It has been found that this largely removes the requirement of high pressure steam cleaning of equipment and the resulting effluent problem. It is also an advantage that the entire reaction system is enclosed. This allows relatively easy removal of steam, water vapour and gases produced in the reaction.

In this embodiment of the invention an agitator can be included at the beginning of the belt close to the discharge from the mixing vessel to ensure that complete mixing takes place before the material passes from the fluid stage. Preferably, the initial part of the belt has a U-shaped cross-section in order to hold the relatively fluid reaction mixture. The initial part of the belt is also arranged to slope downwardly from the reaction vessel to prevent reverse flow or spillage of material. The U-shaped section is selected to have a volume which is sufficient to hold up to 40 minutes' of plant production capacity. During this period, the reaction mixture passes through a fluid and then a plastic stage with the evolution of steam and gases. At the end of the U-shaped section, the belt flattens out to almost its full width but remains slightly curled at the outside edges to minimize the risk of spillage. At the point at which the belt flattens out, the product has already partially dried. The flattening of the belt causes the cake to split open to release steam, moisture and gases trapped inside the cake. The thickness of the cake on the belt is regulated to maximise the surface area available for the escape of steam and hot gases. The cake is then carried by the belt, drying as it moves and, at the end of the belt, the cake falls into a crumbling device. This reduces the particle size of the product and releases steam, moisture and trapped gases. The product is then transported to a second locality for treatment such as granulation, drying, cooling, enrichment, sizing or bagging.

In a preferred embodiment, the entire belt is enclosed by a canopy. Air is drawn through the enclosed space carrying with it steam, water vapour, fumes and gases produced in the reaction. The extracted vapours are treated in a suitable treatment plant.

Preferably the belt will be made of a suitable high temperature resistant material, PTFE, thin stainless steel, wooden slats or the like. The release-nature of the belt is also important. The belt must be sufficiently smooth to allow the product to drop off the belt as it passes around the final pulley. Ideally, no material should adhere to the belt. The enclosed belt system will typically have a width of about 2 m a length of approximately 25 m and a maximum height of about 2 m.

Where the raw materials, or reactants, are dosed on a batch basis, the dosage can be by weight or volume. Where the reactants are dosed on a continuous basis, the amount dosed will be measured by a belt weigher, mass flow meter or a similar dosing device.

The invention extends to an amino acid enriched animal feed produced by a method as hereinbefore described. It is an important feature of the process that it produces an animal feed which has a very high lysine and methionine content. This results in an intake of up to 90g of lysine and 30g of methionine or its hydroxy analogue per day per cow.

During the process of the invention, a composite product matrix is formed which comprises the metal or ammonium salts of the fatty acid, the mineral acid, the amino acids and any other components. Those materials that do not react are effectively evenly dispersed within the complex that is formed.

In preferred embodiments of the invention, animal feeds having the compositions set out below were prepared:

The invention does not require the presence of an inorganic acid in all cases and products such as POFA/POFD-MHA-Ca, POFA/POFD-lysine-Ca, POFA/POFD-lysine-MHA-Ca and lysine-MHA-Ca are prepared without an inorganic acid. Alternatively the process is flexible enough to make products such as POFA/PFAD-lysine-P-Ca, and MHA-P-Ca. Furthermore the process is not limited to producing salts containing calcium. Calcium is convenient as it is very useful in animal nutrition. The invention is now described, with reference to the accompanying examples. In the examples 2-hydroxy-4-(mercaptomethyl)butanoic acid, also referred to as methionine hydroxy analogue-free acid, is referred to as MHA.

EXAMPLE 1

Lysine (50% aqueous solution, 224g), MHA, (88% aqueous solution, 654g) and phosphoric acid (nominally 53,5% P₂O₅, 164g) were rapidly added in the above order to a mixing vessel over a period of 12 seconds and mixing was commenced. Quick lime (nominally 96% CaO, 223g) was then added to the liquid mixture over a period of less than 3 seconds and mixing was continued for a further 5 - 8 seconds. The resulting reaction mixture was then immediately discharged into a second vessel in which the reaction was allowed to go to completion. The temperature peaked at 118°C and, after approximately 18 minutes, the product which was in the form of a mixture of powder and flakes was removed and allowed to stand. It was then spread open and left for about 16 hours, screened and analysed.

The product had a lysine : methionine ratio of approximately 1 :5 and a methionine content of over 50%. The analysis gave the following:

Lysine 10,55% Methionine 54,44% Phosphorous 3,74% Calcium 15,60% Free moisture 2,90%

EXAMPLE 2

Sodium carbonate, (a commercial grade, 117,2g) and quick lime (97% CaO, 329,4g) were thoroughly mixed and the mixture was divided into three equal portions. Lysine (50% aqueous solution, 442, 6g) was mixed with MHA, (88% aqueous solution, 250,4g) and the resulting solution was divided into three equal portions. Three portions of defluorinated phosphoric acid (nominally 51% P₂O₅, 990g) were weighed out.

The first lysine/methionine mixture was added to a mixing vessel, immediately followed by the first phosphoric acid solution with mixing. After a period of 3 - 5 seconds the first quick lime/sodium carbonate mixture was added with vigorous stirring. The resulting mixture was mixed for a further 3 - 15 seconds. Reaction started almost immediately and the reaction mixture was transferred directly after the mixing step to a second reaction vessel over a period of about 10 seconds. The reaction was allowed to run to completion in the second vessel. The second lysine/methionine mixture and the second quick lime/sodium carbonate mixture were then added to the mixing vessel in the same way and the product transferred to the second vessel. The process was repeated for the third lysine/methionine mixture and the third quick lime/sodium carbonate mixture. After the third discharge no further mixing took place and a sample was drawn for analysis. The temperature in the reaction mixture reached 114°C about 12 minutes after the first mixture was prepared. The product was dry enough to discharge from the second vessel within 20 minutes of the start of the first mixing step. The product, which was in the form of a mixture of lumps and powder, was allowed to cool to room temperature and sieved through a 1 ,18 m/m screen. Oversized particles were crushed to pass through the same screen.

The product had a lysine : methionine : phosphorous : calcium ratio of approximately 1 :1 :1 :1 and analysis gave the following:

Lysine 12,6% Methionine 13,7% (expressed as MHA) Phosphorous 13,7% Calcium 13,8% Sodium 2,5% Magnesium 0,7%

The pH of a 10% slurry was 4,7.

EXAMPLE 3

Lysine (50% aqueous solution, 60g), MHA (88% aqueous solution, 13,6g), defluorinated phosphoric acid (nominally 55% P₂O₅, 125,8g), quick lime (approximately 69% CaO, 55,0g) and sodium carbonate (11 ,7g) were added in the above order to a mixing vessel over a period of approximately 45 seconds. The components were mixed for about 8 seconds after the addition of the sodium carbonate and the mixture was then rapidly discharged into a second vessel. The temperature of the reaction mixture ranged from about 82 - 96°C prior to the discharge step. As soon as the mixing vessel had been emptied the same starting materials in the same proportions were again added and the mixture transferred to the second vessel as before. The process was repeated a third time.

The product temperature reached 105°C and the material was dry enough to discharge after 18 minutes. The material was crushed and screened through a 1 ,18 mm screen before analysis.

The product was a non-ruminant feed with a lysine : methionine ratio of approximately 2 : 1. The analysis gave the following

Lysine 14,8% Methionine 6,3% (expressed as MHA) Phosphorous 15,0% Calcium 18,7% Sodium 1 ,7% Magnesium 0,7% Free moisture 3,4% The pH of a 10% slurry was 6,3.

EXAMPLE 4

Lysine (50% aqueous solution, 416g) was mixed with MHA (88% aqueous solution, 109g) to produce an acid mixture, quick lime (approximately 95% CaO, 230,5g) and sodium carbonate (112,6g) were mixed to produce a base mixture. Defluorinated phosphoric acid (approximately 51 % P₂O₅, 313,5g) was mixed with the acid mixture in a mixing vessel for a few seconds and, once the temperature of the mixture reached about 35°C, palm oil fatty acid (736g) was added to the mixture. The base mixture was then added and, as soon as reaction started, the mixture was poured into a second vessel. The maximum temperature reached was 105°C and the overall batch time was approximately 60 seconds.

The product was ruminant animal feed with a lysine : methionine ratio of approximately 2,2:1.

The composition of the palm oil fatty acid was as follows. Acid value mg KOH/g 209 Iodine value P.I/100P 35

Melting point °C 46

<C14 % 0.5

C14 % 1.5

C16 % 45.5 C18:0 % 16.0

C18:1 % 34.0

C18:2 % 1.5

>C18 % 1.0

EXAMPLE 5

Palm fatty acid (736g), lysine (50% aqueous solution, 416g), MHA (88% aqueous solution, 109g), defluorinated phosphoric acid (approximately 51% P₂O₅, 313,5g), quicklime (approximately 95% CaO, 230, 5g) and sodium carbonate (112,5g) were individually combined in a mixing vessel over a period of 25 seconds before being transferred to a reaction vessel

The product was again a ruminant animal feed with a lysine : methionine ratio of 2,2: 1. The analysis gave the following

Fatty acid 44,1% Lysine 12,5% Methionine 5,7% (expressed as MHA) Phosphorous 4,3% Calcium 9,7% Sodium 2,9% Magnesium 0,4% The pH of a 10% slurry was 8,7.

EXAMPLE 6

Palm fatty acid distillate (PFAD) (274g) was melted to form a liquid at 72°C. The liquid acid was added to a Moulinex 276 blender. Lysine (50% aqueous solution, (186g), MHA (88% aqueous solution, (35g) and phosphoric acid (nominally 53% P₂O₅, 137g) were added to the liquid acid with rapid agitation over a period of about 12 seconds. Calcium oxide (approximately 96% CaO, 115g) was then immediately added to the mixture. After a short initiation period of about 5 seconds, an exothermic reaction initiated and the reaction mixture swelled rapidly to over twice its initial volume. Mixing was continued for a further 8 - 10 seconds and the hot reaction mixture was discharged into a second vessel. The entire batching, mixing and discharge steps took place within about 30 seconds of commencement of the PFAD dosing.

The procedure was repeated with a second set of reactants and the reacting material was discharged into the same vessel. The temperature reached a maximum of about 105°C. After less than 25 minutes from initial discharge of the PFAD, the product was a dry free-flowing powder and could be discharged from the holding container.

The product was a ruminant animal feed with a lysine : methionine ratio of approximately 3:1. The analysis gave the following PFAD 43,5%

Lysine 15,3%

MHA 5,0%

Phosphorous 4,4%

Calcium 12,8%

Free moisture 7,8%

Citric acid soluble phosphorous 3,6%

The approximate composition of the palm fatty acid was:

Laurie acid 0.3%

Palmitic acid 45%

Stearic acid 4.5%

Oleic acid 39%

Linoleic acid 10%

Iodine value 48 (Wijs)

Melting point 45°C

Mixed gylceride esters 10%

Density (at 55' ^>C) 0.887 kg

EXAMPLE 7

The example below illustrates the use of a process without the inclusionic acid. Two successive batches were mixed in a Moulinex 276 blender and then discharged into a single container. Each batch consisted of palm oil fatty acid (127,3g) (at 96^°C) which was rapidly and vigorously blended with lysine solution (35, 9g) (nominal 50%) at room temperature. Quicklime (22, Og) was rapidly added to the mixture and the mixture was agitated for a further approximately 6 seconds. The fluid rapidly swelled and this was accompanied by a rapid temperature rise. The reacting magma was then rapidly discharged into a 2-litre container. The second batch was rapidly mixed and discharged as for the first batch into the same container. The temperature rose quickly to 104°C and the magma formed 'strings' and 'balls'. The mixture was then left for approximately 20 minutes before being discharged and broken up.

Analysis gave the following:

Fatty acid 71.1 %

Lysine 10.0%

Calcium 8.7%

Free moisture 3.0%

EXAMPLE 8

Using the above route but with Lysine solution containing 18% free

moisture, resulted in a product that contained 56.8% Lysine, 3.7% P and 1 2.5% Ca.

EXAMPLE 9

Using the same procedure, but using normal commercially available

methionine hydroxy analogue solution, 52% P2O5 phosphoric acid and quicklime

resulted in a product containing 48.2% methionine hydroxy analogue (MHA)

9.5% P, 1 5.0% Ca and 3.5% free moisture.

EXAMPLE 10

Using the same procedure but with the introduction of Palm Fatty

Acid Distillate produced a free-flowing dry product comprising 41 .5 % MHA,

9.2% P, 1 3.9% Ca and 2.7% free moisture.

EXAMPLE 1 1

The example below illustrates the use of the process with the

incorporation of a "heel" of material to assist with the drying of the product. In

this example 1 2 containers of each raw material (bar the fatty acid) were pre-

weighed . The containers were then reweighed after use to determine the exact

amount of each material used:

In each case the following order of addition was used : Lysine base solution

Methionine hydroxy analogue solution

Phosphoric acid

Calcium oxide and melted fatty acid (simultaneously) In each case the fatty acid was weighed immediately prior to

discharge into the mixer. The quantity discharged was determined by the loss in

weight of the container.

Each raw material was rapidly discharged into a conically-shaped

mixing vessel, fitted with a large full-throat ball valve . The conical mixing vessel

is fitted with a high-speed mixer. This in turn discharged into a ribbon-refiner

mixer.

The time taken to discharge the five raw materials was less than 30

seconds per batch. The materials were then mixed for a further 5-8 seconds after

the addition of the calcium oxide / fatty acid.

During this interval the temperature of the magma and volume rise

rapidly. It is essential to discharge the magma before any significant moisture

loss or thickening occurs. The material discharges in less than 5 seconds.

The magma drops into the refiner mixer below (preheated to 80°C) where the reaction proceeds to completion with the evolution of steam.

Once a bed of reactant has accumulated, an outlet in the end cover

of the refiner mixer can be opened and material bled from the reactor either semi-

or continuously, whilst maintaining a bed within the reactor.

This route resulted in a product containing 5.0% Fatty acid, 4.5%

Methionine hydroxy analogue, 21 .4% Lysine, 8.7 % P, 1 7.6% Ca and 7.4% free

moisture. EXAMPLE 12

This example illustrates the production of the salt of calcium lysinate and

dicalcium phosphate. Lysine solutions with concentrations of 60%, 65%, 70%

and 75% respectively were reacted with 96% calcium oxide and nominal 75%

defluorinated animal feed grade phosphoric acid. In each case, the hot lysine

solution (sufficient to provide 1 24g expressed as 1 00% lysine) was rapidly mixed

with the calcium oxide (60g) and the phosphoric acid (80g) for a period of about

20 seconds and the resulting reaction mixture was then dropped into a single

vessel where the reaction was allowed to run to completion. Once the product

had dried, it was screened through a 1 , 1 8 mm sieve and analysed. The samples

made with the differing concentration lysine solutions were free flowing products

containing 40 - 50% lysine, 6,2 - 7,2% phosphorous and 1 4,5 - 1 5,5% calcium. These products were mixed in a modified ribbon blender, sampled and analysed.

The resulting blended product contained 42,5% lysine, 6,4% phosphorous and

1 5,3% calcium .

A conical bottom mixing vessel complete with its own agitator was installed

directly above the ribbon blender. Lysine, 50% concentration (248g) at room

temperature, phosphoric acid (75% concentration) (80g) and 96% calcium oxide

(60g) were rapidly added to the conical bottom mixing vessel and blended over a

period of about 1 8 seconds. The bottom valve of the mixer was then fully

opened and the magma rapidly discharged onto the blended product which had

been pre-warmed to 70° . The magma drained out within 20 seconds. The valve

was then shut and the process repeated.

Once the product bed had reached the overflow level, a set quantity (275g) was

removed through a lower outlet to accommodate the next discharge of magma.

The product was then screened, any oversize material was crushed and the

crushed oversize and fines were returned to the mixer.

After several cycles, it was found that the 50% lysine solution contained too

much water to maintain a suitable dry granular product and it became necessary

to provide a stream of warm air into the mixer to strip off the excess moisture.

A suitable product was obtained by using hot (80°C or more) 50% lysine solution or hot (60°C or more) 60% lysine solution.

It was found that, when working with hot lysine solutions of concentrations

above 65%, the magma thickened very quickly and it became difficult to affect

rapid transfer. Significant thickening took place within 10 seconds of the raw

material addition. However, this was easily overcome by using a mixer which

had a positive downward action that would force the magma out the lower outlet

valve.

EXAMPLE 13

Material from Example 12 was accumulated and returned to the mixer. The material was warmed to 70° with hot air and the same conical mixing apparatus as described in Example 12 was used to apply a reaction magma of palm oil fatty acid (POFA) and quick lime onto the warm granules in the mixer. This resulted in a thin coating on the exterior of the granules already produced. The resulting coating product was separated into four different size fractions and analysed. The analyses of the fractions were all in the following range: 4.0 - 11.0% fatty acid

37.0 - 41.0% lysine

5.5 - 6.7% P

13.9 - 18% Ca

It was noted under the conditions of the trial that the lysine content decreased with decreasing size fraction; whilst the fatty acid (POFA) content increased with decreasing size fraction.

EXAMPLE 14

Using the method of Example 6, (except that the amino acid was increased at the expense of the fatty acid/phosphoric acid and the amino acid solution was maintained at 70° - 75°C), a product comprising palm fatty acid distillate (PFAD), lysine, phosphorous and calcium was produced. Three batches were prepared sequentially in a reaction vessel. The analysis of each batch is set out below. PFAD 50,3 51 ,1 50,8

Lysine (nominal 50%) 165,5 164,5 166,1

Phosphoric acid (75%) 101 ,9 104,1 106,0 Quick lime (CaO) 68,2 68,5 68,5

The PFAD was maintained at 93 - 95°C and the lysine at 73 - 80°C. The product analysed at 14,3% fatty acid, 23,5% lysine, 7,2% phosphorous and 14,3 calcium.

This material was then analysed for total lysine content and for the solubility of lysine in distilled water at 37°. The sample (5g) was stirred in distilled water (900m£) at 37°C for 24 hours at 100 rpm using a Dissolution tester. The lysine content was analysed on an automatic Amino Acid Analyser after extraction of a ground sample with 0,1 N HCt The results are shown graphically below. From the graph it can be seen that about 20% of the sample was undissolved after 6 hours.

Lysine content of Protected Ca-Lysine was analyzed by Automatic Amino Acid Analyzer after 0.1 HCI extration of grounded sample.

Solubility of Lysine (%) in Protected Ca-Lysine (Lysine content.23.2%) 110 100 . 90 80 a . ⁷⁰. -J → 60 o g 50 40 "o 30 20 Ca- Lysine 10

12 16 20 24 hr. hr. 5min. 3 6 12 24 Solubility of Lysine(%) 73.9 80.7 80.3 96.9 96.7 SD 12 7.3 6.9 1.7 9.6

As can be seen from the above results and graph, ±20% of the sample was undissolved after 6 hours.

It is an advantage of the invention illustrated that the products are free- flowing animal feeds suitable for both ruminants and non-ruminants. The method of the invention is flexible enough to provide animal feed containing a wide spectrum of nutrients such as fatty acids, nutrients selected from a range containing phosphate and sulphate salts, salts of calcium, magnesium, sodium and potassium. It is also an advantage of the invention that it is possible to incorporate additional proteinaceous materials such as natural proteins (including hydrolysed casein) or di-, tri- or tetra- peptides, NPN sources, trace elements, anti-oxidants, disintegrants and flavourants.

By varying the amounts of the reactants, a variety of combinations of fatty acids, metallic salts, amino acids, phosphates and sulphates can be produced. This allows for the manufacture of a variety of animal feed products suitable for a range of animals such as high yield dairy cows, ruminants, swine and poultry.

When the product contains mixtures of amino acids such as, but not limited to, lysine and methionine the total amino acid content will typically be between 15 and 50% and preferably be in the range of about 20 - 40% (all m/m). For products containing one amino acid and the salt of one or more inorganic acids, the amino acid content will typically be between about 15 and 75% and the inorganic acid content between about 0,5 and 20%. In the case of the inorganic acid, the concentration would refer to the element e.g. if the acid were phosphoric acid, the concentration would refer to a certain percentage of phosphorous (expressed as P). The ratios between the fatty acid and the amino acid of the product of the invention are typically in the range 5 - 50% fatty acid to 45 - 5% amino acid. For example the fatty acid amino acid ratio is 44:18 in Example 5, 43,5:20,3 in Example 6 and 5:25,9 in Example 8. The method of the invention lends itself to making feedstuffs with even higher amino acid content. The advantage of this is that higher levels of inclusion of amino acids in a feed ration can be obtained (where space is a limitation on formulating) with lower fatty acid content. As indicated earlier, a too high fatty acid content is a disadvantage in feed rations. The invention also provides, in an animal feed ration with limited space, a method of incorporating mineral acids in a useful assimilable form. The products made in accordance with the method of the invention generally do not require a large excess of the base metal or ammonium salt. Where the method of the invention uses 5 - 10% and occasionally 12% excess, prior art methods known to the Applicant typically use 15 - 20% excess.

It is an advantage of the invention that the heat of reaction of the various acid-base components and the heat of hydration is used to drive off water. The reaction components are mixed together in one or more mixing stage and the hot reaction mixture is handled so that water evaporates spontaneously and a friable free- flowing product is obtained. The process may be operated continuously or in batches.

Unlike prior art processes of which the Applicant is aware, the salts of the amino acids; phosphate or sulphates are not pre-formed. The amino acidsrwhicrr are added in solution, react in-situ with the basic metal and ammonium salts present and so form the appropriate salt of the amino acid, whilst within the fatty acid-salt reaction matrix. The Applicant believes that shielding and encapsulation provided by the matrix once it has dried imparts rumen by-pass properties to the amino and salts.

Products produced by prior art processes of which the Applicant is aware, cannot reach the same total nutrient levels achieved by the present invention. This is an advantage over prior art processes as there is a space limitation in every diet. The more nutrients that can be incorporated into each kilogram of diet, the more efficient and lower cost will be the total ration.

It is also an advantage of the method of the invention that it provides extreme flexibility in the composition of the product. This is partially due to the fact that no additional water need be added (unless so desired). In prior art processes known to the Applicant water is added in quantities of up to 30% of the mass of the fatty acid. This water serves the purpose of improving the homogeneity of the reaction mixture and is required for certain reactions and assists in the generation of heat (via hydration reactions). However, this extra water has to be removed by the use of excess heat-generating reagents, or by downstream drying."

Furthermore, there is no need for a large excess of the basic metal or ammonium slats as almost stoichiometric quantities of these components can be employed to achieve a dry free-flowing product.

It is a further advantage of the invention that when using liquid methionine hydroxy analogue as an amino acid source, the natural odours of the other components such as the lysine and fatty acids, mask or eliminate the unpleasant and penetrating odour of mercaptans i.e. the methionine hydroxy analogue smell.

The elimination of the mercaptan odour indicates that the amino acids have been completely encapsulated.

It is also an advantage of the invention that the process works with raw materials of substantially differing purities. For example the process works with phosphoric acid having a P₂Os equivalent of 40 - 55% P₂O₅, quick lime having a purity of 85 - 98%, sodium carbonate having a purity of 90 - 99% and magnesium oxide having a purity of 60 - 95%.

The invention provides a single process producing a product containing fatty acids for energy, essential amino acids such as lysine and methionine, as well as phosphorous, calcium, sodium and magnesium. In addition other amino acids, trace elements or other desirable chemicals, such as anti-oxidants or chelating agents, can be added. The process utilizes the heats of reaction between the various reactants to produce a homogenous reaction matrix. By manipulating the ratios of the various nutrients a range of free flowing products can be made requiring little or not additional drying. The nature of the products is such that they can be dried under partial or full vacuum. The products are also suitable for granulation if desired.

Claims

CLAIMS:

1. A method of producing an amino acid enriched animal feed, the method including the steps of combining and mixing reactants which include at least one amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally at least one fatty acid and water in a first reaction zone, the combining and mixing step being carried out over a first period of 2 - 60 seconds to produce a reaction mixture in the first reaction zone; transferring the reaction mixture at the end of the first period from the first reaction zone to a second reaction zone, the transferring step being carried out over a second period of 2 - 60 seconds; and allowing heat generated by reaction between at least some of the reactants in the second reaction zone to drive off sufficient water to produce a product mixture in the form of an animal feed containing less than about 15%(m/m) water.

2. A method as claimed in claim 1 , in which the animal feed contains less than about 10% (m/m) water.

3. A method as claimed in claim 1 or claim 2, in which the first period is between about 10 and 30 seconds.

4. A method as claimed in any one of the preceding claims in which the second period is between about 2 and 15 seconds.

5. A method as claimed in any one of the preceding claims, in which the reactants include one or more additional components selected from hydrolysed casein, di-peptides, tri-peptides, tetra-peptides, disintegrants and combinations thereof.

6. A method as claimed in claim 5, in which the or each disintegrant is selected from sodium starch and sodium glycollate.

7. A method as claimed in any one of the preceding claims, in which the alkali and alkaline earth metals are selected from Li, Na, K, Ca and Mg.

8. A method as claimed in any one of the preceding claims, in which the base is selected from calcium oxide, calcium hydroxide, magnesium oxide, magnesium carbonate, burnt dolomite (magnesium/calcium oxides), dolomite lime (magnesium/calcium carbonate), sodium carbonate and mixtures thereof.

9. A method as claimed in any one of the preceding claims, in which the fatty acid is in a form selected from the free acid, a salt of the free acid and mixtures thereof.

10. A method as claimed in any one of the preceding claims, in which the fatty acid is selected from C-|₄ - C₂o edible fatty acids and C - C₂₀ edible fatty acid distillates.

11. A method as claimed in claim 10, in which the edible fatty acid is palm oil fatty acid (POFA) and the edible fatty acid distillate is palm oil fatty acid distillate (PFAD).

12. A method as claimed in any one of the preceding claims, in which the at least one amino acid is selected from lysine, methionine, 2-hydroxy- 4(mercaptomethyl)butanoic acid, threonine, proline, hydroxyproline, ornithine, arginine and mixtures thereof.

13. A method as claimed in any one of the preceding claims, in which the at least one amino acid is provided in the form of an aqueous solution.

14. A method as claimed in claim 13, in which the aqueous solution of the amino acid has a concentration of about 25 - 98%.

15. A method as claimed in any one of the preceding claims, in which the inorganic acid is selected from phosphoric acid, sulphuric acid and mixtures thereof.

16. A method as claimed in any one of claims 12 to 15 inclusive, in which the reactants include lysine and methionine and in which the mass ratio between the lysine and methionine is between about 1 :5 and 5:1.

17. A method as claimed in any one of the preceding claims, in which the molar ratio between the total amount of base and the total amount of acid is between about 0,70 : 1 ,00 and 1 ,30 : 1 ,00.

18. A method as claimed in any one of the preceding claims, in which the total amount of water present during the combining and mixing step is between about 2 and 45% of the total mass of the reactants.

19. A method of producing an amino acid enriched animal feed, the method including the steps of combining and mixing reactants which include at least one amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water in a first reaction zone to produce a reaction mixture in the first reaction zone; and continuously transferring the reaction mixture from the first reaction zone to a second reaction zone, the reactants being added to the first reaction zone in successive batches and the reaction mixture being continuously removed from the first reaction zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is between about 2 and 60 seconds; and allowing heat generated by reaction between at least some of the reactants in the second reaction zone to drive off sufficient water to produce a product mixture containing less than about 15% water.

20. A method as claimed in claim 19, in which the heat generated is allowed to drive off sufficient water to produce a product mixture containing less than about 10% water.

21. A method as claimed in claim 19 or claim 20, in which the rate of removal of the reaction mixture from the first reaction zone is between about 10 and about 10000 kg per hour.

22. A continuous method of producing an amino acid enriched animal feed, the method including the steps of simultaneously feeding, into a first reaction zone, reactants comprising an amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water to produce a reaction mixture in the first reaction zone; and - - . - -. _ .. -. . - _ transferring the reaction mixture from the first reaction zone to a second zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is sufficient to allow heat generated by reaction between the reactants in the first reaction zone to drive off at least some of the water and allowing heat generated by further reaction in the second zone to drive off sufficient water to produce a product mixture containing less than about 15% water, the rate of transferring being selected so that the residence time of the reaction mixture in the first reaction zone is between about 2 and 60 seconds.

23. A continuous method of making an amino enriched animal feed, the method including the steps of simultaneously feeding, into a first reaction zone, reactants comprising an aqueous solution of an amino acid, at least one base selected from aqueous ammonia and the oxides, hydroxides and carbonates of a metal selected from the alkali and the alkaline earth metals and mixtures thereof, optionally at least one inorganic acid, optionally one or more fatty acids and water to produce a reaction mixture in the reaction zone; and transferring the reaction mixture from the first reaction zone to a second zone at a rate which is selected so that the residence time of the reaction mixture in the first reaction zone is between about 5 and 60 seconds and is sufficient to initiate reaction between at least some of the reactants but not sufficient to drive off any substantial amount of water from the reaction mixture and allowing heat generated by further reaction between at least some of the reactants in the second zone to drive off sufficient water to produce a product mixture containing less than about 15% water.

24. An amino acid enriched animal feed produced by a method as claimed in any one of the preceding claims.