EP1926392A1

EP1926392A1 - Method for producing solid enzyme granulates for animal food

Info

Publication number: EP1926392A1
Application number: EP06793398A
Authority: EP
Inventors: Markus Lohscheidt; Roland Betz; Jörg Braun; Wolf Pelletier; Andreas Habich; Peter Ader
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2005-09-12
Filing date: 2006-09-11
Publication date: 2008-06-04
Also published as: CN101291594A; TW200728462A; WO2007031481A1; RU2008113850A; DE102005043327A1; BRPI0615854A2; AR055427A1; US20090263543A1

Abstract

The invention relates to novel methods for producing coated, granulated animal food additives which contain enzymes, and to the coated granulates which contain enzymes and which are produced in said manner, in addition to animal food compositions which can be obtained using the coated granulates. Said method consists of the following steps : a) a dough containing said enzyme, which contains, in addition to water, i) 50 96.9 wt.-% of at least solid carrier material which is suitable for animal food, ii) 0.1 - 20 wt.-% of at least one polymer which is water-soluble, iii) 3 49.9 wt.% of at least one enzyme, is extruded, wherein the weight proportion of i), ii) and iii) are respectively relative to the non-aqueous components of the dough; b) the extruded product is prepared into a raw granulate having a water content of not more than 15 wt.%, and c) the raw granulate is coated with a hydrophobic material which is selected from at least 70 wt.%, in relation to the hydrophobic material, from saturated fatty acids, the esters of saturated acids, in particular mono-, di- and triglycerides of saturated fatty acids, and mixtures thereof.

Description

Process for the preparation of solid enzyme granules for feed

description

The present invention relates to novel processes for the preparation of coated granulated enzyme-containing feed additives, the coated enzyme-containing granules prepared in this manner, and to feed compositions obtainable using the coated granules.

It is common practice to add enzymes to the animal feed to ensure better feed utilization, better product quality or less environmental impact. Moreover, it is common practice to feed animal feed in pelleted form, as pelleting not only facilitates feed intake but also improves handling of the feed. In addition, it has been shown that in the case of pelleted feed certain feed ingredients are better digested and added to the feed ingredients such. As vitamins, enzymes, trace elements, can be better included in the feed mixture.

To reduce the germ burden (sanitization) of such animal feed is often carried out a heat treatment. Heat treatment also takes place in the context of the conditioning required for pelleting, in which the feed is steamed and thereby heated and moistened. In the actual pelleting step, the feed is pressed through a die. Other processes used in the feed industry include extrusion and expansion. The effect of heat in all these processes is a problem especially when enzymes, which are usually thermally unstable, are included in the feed mixture. Various efforts have therefore been made to improve the thermal stability and in particular the pelleting stability of enzyme-containing feed compositions.

In EP-A-0 257 996, for example, it is proposed to stabilize enzymes for feed mixtures by pelleting them in admixture with a carrier having a major proportion of cereal flour.

WO 98/54980, in turn, describes enzyme-containing granules with improved pelleting stability, which are prepared by extrusion of an aqueous enzyme solution with an edible carbohydrate carrier and subsequent drying.

In WO 92/12645 it is proposed to convert feed enzymes into so-called T

To incorporate granules. This T granulate comprises a proportion of 2 to 40% by weight. Cellulose fibers. This particular granule is then coated in a specific manner. The coating comprises a high proportion, preferably about 60 to 65% by weight of an inorganic filler, such as. Kaolin, magnesium silicate or calcium carbonate. As is apparent from the embodiments of WO 92/12645, a one-step application of the coating is not possible. Rather, in several steps alternately a high-melting fat or wax and the filler must be applied to the T-granules. The disadvantages of the approach proposed in this prior art for improving pelleting stability are evident. On the one hand, a very special carrier material is absolutely necessary; on the other hand, a complex multistage coating of the carrier material is necessary.

WO 01/00042 in turn teaches polymer-coated enzyme granules. The use of fats for coating is described as disadvantageous.

WO 03/059086 in turn teaches a process for the preparation of enzyme granules having improved pelleting stability, in which an enzyme-containing raw granules are coated with an aqueous dispersion of a hydrophobic substance. In the case of fat dispersions, this method does not provide satisfactory pelleting stabilities.

It is therefore an object of the present invention to provide a process for the preparation of enzyme-containing feed additives with improved pelleting stability.

It has surprisingly been found that enzyme granules with particularly good pelleting stability are obtained by the process described in more detail below. This procedure includes the following steps:

a) extrusion of an enzyme-containing dough, which besides water i) 50 to 96.9 wt .-% of at least one suitable for feed solid,

Ii) from 0.1 to 20% by weight, of at least one water-soluble polymer, iii) from 3 to 49.9% by weight of at least one enzyme, the proportions by weight of i), ii) and iii) each based on the non-aqueous components of the dough; b) preparing the extrudate into a raw granulate having a water content of not more than 15% by weight, and c) coating the raw granules with a hydrophobic material containing at least 70% by weight, based on the hydrophobic material, of saturated fatty acids , the esters of saturated fatty acids, in particular the mono-, di- and triglycerides of saturated fatty acids, and mixtures thereof is selected. Accordingly, the invention relates to such a process and the enzyme granules obtainable by this process as well as feed compositions, in particular hydrothermally treated and especially feed compositions in pelletized form, which contain such an enzyme granulate.

According to the invention, the production of the raw granulate in a first step comprises the extrusion of a hydrous dough comprising at least one feed material suitable for feed.

Conventional inert inorganic or organic carriers can be used as feed-compatible carrier materials. An "inert" carrier must not show negative interactions with the enzyme (s) of the feed additive of the invention, such as e.g. B. cause irreversible inhibition of enzyme activity, and must be safe for use as an adjuvant in feed additives. Examples of suitable support materials are: low molecular weight organic compounds and higher molecular weight organic compounds of natural or synthetic origin and inert inorganic salts. Preference is given to organic support materials. Of these, carbohydrates are particularly preferred.

Examples of suitable low molecular weight organic carriers are in particular sugars, such as. As glucose, fructose, sucrose. Examples of higher molecular weight organic carriers are carbohydrate polymers, in particular those which contain α-D-glucopyranose, amylose or amylopectin units, in particular native and modified starches, microcrystalline cellulose but also α-glucans and β-glucans, pectin (cf. including protopectin) and glycogen. Preferably, the carrier material comprises at least one water-insoluble polymeric carbohydrate, in particular a native starch material, in particular corn starch, rice starch, wheat starch, potato starch, starches from other vegetable sources such as starch from tapioca, cassava, sago, rye, oats, barley, sweet potato, arrowroot and The like, continue to consume flour such. B. corn, wheat, rye, barley and oatmeal and rice flour. Also suitable in particular are mixtures of the abovementioned carrier materials, in particular mixtures which comprise predominantly, ie at least 50% by weight, based on the carrier material, one or more starch materials. The water-insoluble carbohydrate preferably constitutes at least 50% by weight, in particular at least 65% by weight and especially at least 80% by weight, of the support material. Particularly preferred carrier materials are starches which contain not more than 5% by weight and in particular not more than 2% by weight of protein or other constituents. Another preferred carrier material is microcrystalline cellulose. This can be used alone or in admixture with the abovementioned support materials. If the microcrystalline cellulose is used in admixture with other carrier materials, it preferably makes no more than 50% by weight, in particular no more as 30 wt .-%, for example 1 to 50 wt .-%, in particular 1 to 30 wt .-% and especially 1 to 10 wt .-% of the carrier material from.

Suitable inorganic carrier materials are in principle all inorganic carrier materials known for feed and feed additives, for example inert inorganic salts, e.g. Sulfates or carbonates of alkali and alkaline earth metals such as sodium, magnesium, calcium and potassium sulfate or carbonate, further feed-compatible silicates such as talc and silicic acids. The amount of inorganic carrier material, based on the total amount of carrier material, will generally not exceed 50% by weight, especially 35% by weight and very particularly 20% by weight. In a preferred embodiment, the organic carrier materials make up the total amount or almost the total amount, i. at least 80% by weight of the support material.

The carrier material is usually from 50 to 96.9 wt .-%, often 55 to 94.5 wt .-% and in particular 60 to 90 wt .-%, of the non-aqueous constituents of the dough and is accordingly in these quantities in the containing enzyme granules according to the invention.

In addition to the feed-compatible carrier material according to the invention the dough to be extruded contains at least one water-soluble polymer. This polymer acts as a binder and at the same time increases pelleting stability. Preferred water-soluble polymers have a number-average molecular weight in the range from ⁵ × 10 ³ to ⁵ × 10 ⁶ DaIton, in particular in the range from ¹ × 10 ⁴ to ¹ × 10 ⁶ daltons. The polymers are considered to be water soluble if at least 3 g of polymer can be completely dissolved in 1 liter of water at 20 ° C.

The water-soluble polymers used according to the invention include

Polysaccharides, e.g. water-soluble modified starches with generally sticking properties, for example starch degradation products (dextrins) such as acid dextrins, roast dextrins, enzymatic partial hydrolysates (limiting dextrins), oxidatively degraded starches and their reaction products of dextrins with cationic or anionic polymers, reaction products of dextrins with Octyl succinate anhydride (OSA), starch glue, furthermore chitin, chitosan, carrageen, alginates, arabic acid salts, gums, eg Gum arabic, tragacanth, karaya

Rubber; Xanthan gum and gellan gum; galactomannans; water-soluble cellulose derivatives, for example methylcellulose, ethylcellulose and hydroxyalkylcelluloses, for example hydroxyethylcellulose (HEC), hydroxyethylmethylcellulose (HEMC), ethylhydroxyethylcellulose (EHEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC) and hydroxybutylcellulose, and also carboxymethylcellulose (CMC ); water-soluble proteins, for example proteins of animal origin such as gelatin, casein, in particular sodium caseinate and vegetable proteins such as soy protein, pea protein, bean protein, rape protein, sunflower protein, cottonseed protein, potato protein, lupine, zein, wheat protein, corn protein and rice protein, synthetic polymers, for example polyethylene glycol , Polyvinyl alcohol and in particular the Kollidon brands from BASF, vinyl alcohol-vinyl ester copolymers, homo- and copolymers of vinylpyrrolidone with vinyl acetate and / or CrC ₄ -alkyl acrylates, and optionally modified biopolymers, for example lignin or polylactide.

Preferred water-soluble polymers are neutral, i. they have no acidic or basic groups. These include polyvinyl alcohols, including partially saponified polyvinyl acetates having a degree of saponification of at least 80%, and especially water-soluble, neutral cellulose ethers such as methylcellulose, ethylcellulose and hydroxyalkylcelluloses such as e.g. Hydroxyethylcellulose (HEC), hydroxyethylmethylcellulose (HEMC), ethylhydroxyethylcellulose (EHEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC) and hydroxybutylcellulose are particularly preferred.

In a preferred embodiment of the invention, the water-soluble polymer is selected from neutral cellulose ethers. Examples of water-soluble, neutral cellulose ethers which are preferred according to the invention are methylcellulose, ethylcellulose and hydroxyalkylcelluloses, e.g. Hydroxyethylcellulose (HEC), hydroxyethylmethylcellulose (HEMC), ethylhydroxyethylcellulose (EHEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC) and hydroxybutylcellulose. Of these, methylcellulose, ethylcellulose and mixed cellulose ethers having methyl groups or ethyl groups and hydroxyalkyl groups such as HEMC, EHEC and HPMC are particularly preferred. Preferred methyl- or ethyl-substituted cellulose ethers have a degree of substitution DS (with respect to the alkyl groups) in the range from 0.8 to 2.2, and in the case of mixed cellulose ethers a degree of substitution DS with respect to the alkyl groups in the range from 0.5 to 2, 0 and a degree of substitution HS with respect to the hydroxyalkyl groups in the range of 0.02 to 1, 0 on.

The proportion of water-soluble polymers is preferably in the range of 0.2 to 10 wt .-%, in particular 0.3 to 5 wt .-% and especially 0.5 to 3 wt .-%, based on the dough forming, non-aqueous Components and is therefore part of the enzyme-containing raw granules in these amounts.

Furthermore, the dough contains at least one enzyme, although mixtures of different enzymes may also be present. Typical enzymes for animal feed are eg oxidoreduclear tases, transferases, lyases, isomerases, ligases, lipases and hydrolases.

Examples of hydrolases, d. H. Enzymes which cause a hydrolytic cleavage of chemical bonds are esterases, glycosidases, ether hydrolases, proteases, amidases, aminidases, nitrilases and phosphatases. Glycosidases (EC 3.2.1, also referred to as carbohydrases) include both endo- and exo-glycosides which cleave both α- and β-glycosidic bonds. Typical examples of these are amylases, maltases, keratinases, cellulases, endo-xylanases, e.g. endo-1, 4-.beta.-xylanase or xylan-endo-1,3-.beta.-xylosidase, .beta.-glucanases, in particular endo-1, 4-.beta.- and endo-1,3-.beta.-glucanases, mannanases, lysozymes, Galactosidases, pectinases, β-glucuronidases and the like. The inventive method is particularly suitable for producing pelletierstabiler enzyme granules, which are non-starch polysaccharide-cleaving enzymes such. As glucanases, and xylanases, and in particular phosphatases (EC 3.1.3) and especially phytases (EC 3.1.3.8, 3.1.3.26 and 3.1.3.72) are selected.

The term "phytase" encompasses both natural phytase enzymes and any other enzyme which exhibits phytase activity, for example, capable of catalyzing a reaction by which phosphorus or phosphate is released from myo-inositol phosphates. The phytase may be either a 3-phytase (EC 3.1.3.8) or a 4- or 6-phytase (EC 3.1.3.26) or a 5-phytase (EC 3.1.3.72) or a mixture act on it. The phytase preferably belongs to the enzyme class EC 3.1.3.8.

The phytase preferably used as the enzyme in the process of the present invention is not limited and may be of microbiological origin as well as a phytase obtained by genetic modification of a naturally occurring phytase or by de novo construction. The phytase may be a plant phytase, fungi, bacteria or a phytase produced by yeasts. Preferred are phytases from microbiological sources such as bacteria, yeasts or fungi. However, they can also be of plant origin. In a preferred embodiment, it is a phytase from a fungus strain, in particular from an Aspergillus strain, eg Aspergillus niger, Aspergillus oryzae, Aspergillus ficuum, Aspergillus awamori, Aspergillus fumigatus, Aspergillus nidulans or Aspergillus terreus. Particularly preferred are phytases derived from a strain of Aspergillus niger or a strain of Aspergillus oryzae. In another preferred embodiment, the phytase is derived from a bacterial strain, especially a Bacillus strain, an E. coli strain or a Pseudomonas strain, of which phytases derived from a Bacillus subtilis strain are preferred. In another preferred embodiment, the phytase is from a yeast, in particular a Kluveromyces strain or a Saccharomyces strain, of which phytases derived from a strain of Saccharomyces cerevisiae are preferred. In this invention, the term "an enzyme derived from one" encompasses the enzyme naturally produced by the respective strain, which is either derived from the strain or encoded by a DNA sequence isolated from the strain, and by a host organism that interacts with that DNA. Sequence was transformed, is produced. The phytase can be recovered from the respective microorganism by known techniques, which typically involves the fermentation of the phytase producing microorganism in a suitable nutrient medium (see, for example, ATCC catalog) and subsequent recovery of the phytase from the fermentation medium by standard techniques. Examples of phytases as well as methods for the preparation and isolation of phytases can be found in EP-A 420358, EP-A 684313, EP-A 897010, EP-A 897985, EP-A 10420358, WO 94/03072, WO 98/54980, WO 98/55599, WO 99/49022, WO 00/43503, WO 03/102174, the disclosure of which is hereby expressly incorporated by reference.

The amount of enzyme in the dough, of course, depends on the desired activity of the enzyme granules and the activity of the enzyme employed, and is typically in the range of 3 to 49.9% by weight, often in the range of 5 to 49.7% by weight. %, in particular in the range of 10 to 45 wt .-%, and especially in the range of 10 to 39 wt .-%, calculated as dry matter and based on the total weight of all non-aqueous constituents of the dough.

Furthermore, the dough used in step a) may additionally contain a salt stabilizing the enzyme. The stabilizing salts are typically salts of divalent cations, in particular salts of calcium, magnesium or zinc, and salts of monovalent cations, in particular of sodium or potassium, for example the sulfates, carbonates, bicarbonates and phosphates including hydrogen phosphates and ammonium hydrogen phos- phates of these metals. Preferred salts are the sulfates. Particularly preferred are magnesium sulfate and zinc sulfate, including their hydrates. The amount of salt is preferably in the range of 0.1 to 10 wt .-%, in particular in the range of 0.2 to 5 wt .-%, and especially in the range of 0.3 to 3 wt .-%, based on the total weight of all non-aqueous components of the dough.

In addition to the aforementioned ingredients, the dough contains water in an amount which ensures sufficient homogenization of the constituents of the dough and a sufficient consistency (plasticization) of the dough for the extrusion. The amount of water required for this purpose can be determined by a person skilled in the art of enzyme formulation in a manner known per se. The water content in the dough is typically in the range of> 15 to 50 wt .-%, especially in the range from 20 to 45% by weight and especially in the range of from 25 to 40% by weight, based on the total weight of the dough.

In addition, the dough may contain other ingredients in a minor amount, which usually make up not more than 10 wt .-% of the dough, for example, means for adjusting the pH such as buffer (phosphate buffer, potassium or sodium phosphate, their hydrates or dihydrates , Sodium or potassium carbonate), bases (sodium, potassium, calcium, magnesium or ammonium hydroxide, ammonia water) or acids (inorganic or organic acids, hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, acetic acid, formic acid, propionic acid). It is also possible to add further fillers to the dough which positively influence the properties of the dough, such as, for example, flow behavior or sticking behavior. These include substances such as salts (inorganic salts, sulfates or carbonates of alkali and alkaline earth metals, sodium, magnesium, calcium, potassium or zinc salts), sugars (glucose, fructose, sucrose, dextrins) or talc, microcrystalline cellulose and silicas.

The preparation of the dough is carried out in a conventional manner by mixing the constituents of the dough in a suitable mixing device, for example in a conventional mixer or kneader. For this, the solid (s), e.g. the support material, with the liquid phase, for example water, an aqueous binder solution or an aqueous enzyme concentrate, intensively mixed. In general, the carrier is introduced as a solid into the mixer and with an aqueous enzyme concentrate and with the water-soluble polymer, preferably in the form of a separate aqueous solution or dissolved in the aqueous enzyme concentrate, and optionally with the stabilizing salt, preferably in the form of a separate aqueous solution or suspension, in particular dissolved or suspended in the aqueous enzyme concentrate. Optionally, additional water will be added to adjust the desired consistency of the dough. It is preferable to not exceed a temperature of 60.degree. C., in particular of 40.degree. C., during thorough mixing. More preferably, the temperature of the dough during mixing is 10 to 30 ° C. Optionally, therefore, one will cool the mixing device during mixing.

Furthermore, it has been proven to control the pH of the aqueous phase before or during dough preparation. According to a preferred embodiment of the invention, therefore, a pH in the range of 3.5 to 7, in particular in the range of 4 to 6 and especially in the range of 4.5 to 5.5 will be set. The pH adjustment surprisingly also leads to a better stability of the enzyme granules, especially when the enzyme is a hydrolase and especially a

Phosphatase acts. To adjust the pH, you can, for example, a Use acid or base or a buffer. Preferably, one will choose such pH adjusting agents as are permitted in feeds. The pH adjusting agent may be added either to the dough as such or together with one of the aforementioned constituents of the dough, preferably in the form of an aqueous solution. In particular, the agent for adjusting the pH in a form dissolved in the enzyme concentrate is added. Accordingly, the pH of the enzyme concentrate is preferably adjusted before mixing according to the above-mentioned ranges. The means for adjusting the pH naturally depends on the pH, which is established by mixing the constituents. Since the enzyme concentrate often has a weakly acidic pH below 4, it is preferred to add a buffer or a base. Suitable bases are, in addition to ammonia, ammonia water and ammonium hydroxide, alkali metal and alkaline earth metal salts, such as, for example, sodium, potassium, magnesium and calcium hydroxides, citrates, acetates, formates, hydrogen formates, carbonates and bicarbonates, and amines and alkaline earth metal oxides, such as CaO and MgO. Examples of inorganic buffering agents are alkali metal hydrogen phosphates, in particular sodium and potassium hydrogen phosphates, for example K ₂ HPO ₄ , KH ₂ PO ₄ and Na ₂ HPO ₄ .

The preferred means for adjusting the pH is ammonia or ammonia or sulfuric acid. Suitable buffers are e.g. Mixtures of the abovementioned bases with organic acids such as acetic acid, formic acid, citric acid.

The dough thus obtained is then subjected to extrusion, preferably low pressure extrusion. The extrusion, in particular the extrusion at low pressure, is usually carried out in an apparatus in which the mass to be extruded (dough) is pressed through a die. The hole diameter of the die determines the particle diameter and is usually in the range of 0.3 to 2 mm and in particular in the range of 0.4 to 1, 0 mm. Suitable extruders are for. B. Domextruder or basket extruder, which are sold, inter alia, by companies such as Fitzpatrick or Bepex. With correct consistency of the mass to be granulated, this results in only a slight increase in temperature when passing through the die (up to about 20 ° C). Preferably, the extrusion is under temperature control, i. the temperature of the dough should not exceed a temperature of 70 ° C, especially 60 ° C during extrusion. In particular, the temperature of the dough during extrusion is in the range of 20 to 50 ° C.

The extruded dough strands leaving the extruder break up into short granular particles or, if appropriate, can be broken with the aid of suitable cutting devices. The granulate particles thus obtained typically have a homogeneous grain size, ie a narrow particle size distribution. In this way, a raw granules having a comparatively high water content, which is generally more than 15 wt .-%, for example in the range of 15 to 50 wt .-%, in particular in the range of 20 to 45 wt .-%, based on the total weight of the wet raw granules. According to the invention, it is therefore formulated prior to coating in such a way that its water content is not more than 15% by weight and preferably in the range from 1 to 12% by weight, in particular in the range from 3 to 10% by weight and especially in the Range of 5 to 9 wt .-% is.

Accordingly, the packaging usually comprises a drying step. This is preferably carried out in a fluidized bed dryer. In this case, a heated gas, usually air or a nitrogen gas stream, passed from below through the product layer. The amount of gas is usually adjusted so that the particles are fluidized and swirl. The heat transfer gas / particles evaporates the water. Since enzyme-containing raw granules are usually temperature labile, it will be important to ensure that the temperature of the raw granules does not rise too high, ie usually not above 80 ⁰ C and preferably not above 70 ⁰ C. In particular, the temperature of the granules during drying in the range of 30 to 70 ° C. The drying temperature can be easily controlled by the temperature of the gas flow. The temperature of the gas stream is typically in the range of 140 to 40 ° C and in particular in the range of 120 to 60 ° C. Drying can be continuous and discontinuous.

After drying, the granules can be fractionated by means of a sieve (optional). Coarse and fine material can be ground and returned to the mixer for the preparation of the extrusion of the granulation mass.

Furthermore, it has proved to be advantageous to round the still moist raw granules before carrying out the drying, i. to spheronize. In particular, the formation of unwanted dust in the end product is reduced.

Devices suitable for rounding the moist raw granules are so-called spheronizers, which essentially have a horizontally rotating disk on which the stringers are pressed against the wall by the centrifugal force. The stringers break up at the predetermined by the extrusion process micro-notches, so that cylindrical particles with a diameter to length ratio of about 1: 1, 3 to 1: 3 arise. Due to the mechanical stress in the spheronizer, the initially cylindrical particles are rounded somewhat.

The raw granules obtained after the preparation advantageously have an average particle size in the range from 100 to 2000 .mu.m, in particular in the range from 200 to 1500 .mu.m and especially in the range from 300 to 1000 .mu.m. The middle part Chen size distribution can be determined in a conventional manner by light scattering, eg with a Mastersizer S, the company. Malvern Instruments GmbH or sieve analysis, eg with a screening machine type Vibro VS 10000 Fa. Retsch. The average particle size is understood by the person skilled in the art to be the so-called D50 value of the particle size distribution curve, ie the value which exceeds or falls below 50% by weight of all particles. Preference is given to crude granules having a narrow particle size distribution.

Subsequently, the granules thus obtained are provided with a hydrophobic coating. According to the invention, the material forming the coating consists of at least 70% by weight, especially at least 80% by weight, in particular at least 90% by weight, of saturated fatty acids, fatty acid esters or mixtures thereof.

Saturated means that the hydrophobic material is substantially free of unsaturated constituents and accordingly has an iodine value below 5 and in particular below 2 (method according to Wijs, DIN 53 241).

Fatty acid esters are in particular the mono-, di- and triglycerides of saturated fatty acids and esters of fatty acids with saturated fatty alcohols having, for example, 10 to 32 C atoms, in particular having 16 to 24 C atoms, such as cetyl alcohol or stearyl alcohol.

The fatty acids or the fatty acid residues in the fatty acid esters preferably have 10 to 32 C atoms, frequently 12 to 24 C atoms and in particular 16 to 22 C atoms. Preference is given to hydrophobic materials having melting points in the range from 40 to 95.degree. C., in particular in the range from 45 to 80.degree. C., in particular in the range from 50 to 70.degree.

The hydrophobic material is preferably low in acid and has an acid number below 80, in particular below 30 and especially below 10 (determined according to ISO 660). Particularly preferably, the hydrophobic material consists of at least 70% by weight, in particular at least 80% by weight and especially at least 90% by weight, of the abovementioned triglycerides.

In a preferred embodiment of the invention, the coating composition predominantly, ie at least 70 wt .-%, in particular at least 80 wt .-% and especially over 90 wt .-% hydrogenated vegetable oils including triglycerides, eg hydrogenated cottonseed, corn, peanut , Soybean, palm, palm kernel, babas, rape, sunflower and safflower oils. Among these, particularly preferred hydrogenated vegetable oils are hydrogenated palm oil, cottonseed oil and soybean oil. The most preferred hydrogenated vegetable oil is hydrogenated soybean oil. In the same way, other fats and waxes derived from plants and animals are also is suitable, for example, bovine fat. Also suitable are nature-identical fats and waxes, ie synthetic waxes and fats with a composition that corresponds to the natural products predominantly.

The following table lists some examples of suitable coating materials according to the invention.

Also suitable are the products marketed under the trade name Vegeol PR from Aarhus ONe, DK, eg Vegeol® PR 267, PR 272, PR 273, PR 274, PR 275, PR 276, PR 277, PR 278 and PR 279. The amount of hydrophobic material is usually 1 to 35 wt .-%, preferably 4 to 30 wt .-%, in particular 5 to 25 wt .-% and especially 7 to 21 wt .-%, based on the used and dried raw granulate.

The application of the hydrophobic material can be carried out in a manner known per se by applying a solution, dispersion or suspension of the hydrophobic material in a suitable solvent, for example water, or by applying a melt of the hydrophobic material. The application of a melt is inventively preferred, because this can be dispensed sions or dispersing the subsequent removal of the solvent. That is, for the application of a melt, the use of an expensive dryer / coater (e.g., a fluidized bed dryer) is not required, but the use of a mixer becomes possible. Coating with a melt of the hydrophobic material is also referred to below as melt-coating.

Suitable methods of applying the coating include coating in a fluidized bed or fluidized bed, and coating in a mixer (continuous or batchwise), e.g. a granulating drum, a plowshare mixer e.g. Fa. Lödige, a paddle mixer e.g. Forberg, a Nauta mixer, a granulating mixer, a granulating dryer, a vacuum coater e.g. Fa. Forberg or a high-shear granulator done.

In particular, the coating of the raw granulate i) takes place in a fluidized bed or in a fluidized bed, e.g. by spraying the raw granules with a melt, a solution or dispersion of the hydrophobic material; and ii) in one of the aforementioned mixing devices by introducing the raw granules into a melt of the hydrophobic material or by spraying or dousing the raw granules with a melt, a solution or dispersion of the hydrophobic material.

Coating by spraying the raw granules with a melt, a solution or dispersion in a fluidized bed or in a fluidized bed is particularly preferred according to the invention. The spraying of the raw granules with a melt, a solution or dispersion of the hydrophobic material can in principle in the fluidized bed apparatus in the bottom spray method (nozzle sits in the distributor plate and sprays upwards) or in the top-spray method (coating is from above in the Fluidized bed sprayed) are performed.

The coating of the raw granules can be carried out continuously or discontinuously within the scope of the process according to the invention. According to a first preferred embodiment of the method according to the invention, the raw granules are introduced into a fluidized bed, vortexed and coated by spraying an aqueous or non-aqueous, preferably aqueous dispersion of the hydrophobic material with this material. For this purpose, preferably a highly concentrated, still sprayable liquid, such as. Example, a 10 to 50 wt .-% aqueous dispersion or nonaqueous solution or dispersion of the hydrophobic material.

The spraying of the solution or dispersion of the hydrophobic material is preferably carried out so as to submit the raw granules in a fluidized bed apparatus or a mixer and sprayed with simultaneous heating of the template, the sprayed. The energy is supplied in the fluidized bed apparatus by contact with heated drying gas, often air. A preheating of the solution or dispersion may be useful if sprayed with higher dry matter content can be sprayed. In the case of the use of organic liquid phases, solvent recovery is expedient and the use of nitrogen as a drying gas to avoid explosive gas mixtures is preferred. The product temperature during the coating should be up to 60 ° C in the range of about 30 to 80 ⁰ C and in particular in the range of 35 to 70 ° C and especially in the range of 40th The coating can be carried out in the fluidized bed apparatus in principle by the bottom spray method (nozzle is located in the distributor plate and sprayed upward) or in the top spray method (coating is sprayed from above into the fluidized bed). When using a mixer for coating, after spraying the solution or dispersion, the solvent or the liquid of the dispersion must be removed. This can be done in a dryer.

According to a second, particularly preferred embodiment of the method according to the invention, the coating of the raw granules presented in a fluidized bed or mixer takes place by means of a melt of the hydrophobic material. The melt coating in a fluidized bed is preferably carried out by initially charging the raw granules to be coated in the fluidized bed apparatus. The hydrophobic material is melted in an external reservoir and pumped for example via a heatable line to the spray nozzle. A heating of the nozzle gas is appropriate. Spray rate and inlet temperature of the melt are preferably adjusted so that the hydrophobic material still runs well on the surface of the granules and this covers evenly. Preheating of the granules before injection of the melt is possible. In the case of hydrophobic materials with a high melting point, the temperature will generally be chosen so that a loss of enzyme activity is largely avoided. The product temperature should preferably be in the range of about 30 to 80 ⁰ C and in particular in the range of 35 to 70 ° C and spe- range from 40 to 60 ° C. The melt coating can also be carried out in principle by the bottom spray method or by the top spray method.

Melt-coating in a mixer can be done in two different ways. Either put the granules to be coated in a suitable mixer and spray or pour a melt of the hydrophobic material into the mixer. Another possibility is to mix the solid-form hydrophobic material with the product. By supplying energy via the container wall or via the mixing tools, the hydrophobic material is melted and thus coats the raw granules. Depending on requirements, some release agent may be added from time to time. Suitable release agents are, for example, silica, talc, stearates and tricalcium phosphate, or salts such as magnesium sulfate, sodium sulfate or calcium carbonate.

The solutions, dispersions or melts used for the coating may optionally contain other additives, such as. As microcrystalline cellulose, talc and kaolin, or salts are added.

In a particular embodiment of the method according to the invention, it is possible to dispense with the addition of release agents during the application of the hydrophobic material or the addition of release agent to the solution, dispersion or melt to be applied. This is possible in particular if the enzyme cores used have mean particle sizes of at least 300 μm, preferably at least 350 μm, in particular at least 400 μm, e.g. In the range of

250 to 1600 microns, preferably in the range of 300 microns to 1500 microns and in particular in the range of 400 microns to 1400 microns, and at the same time the amount of hydrophobic coating material used based on the total particle not more than 30 wt .-%, preferably not more than 25% by weight, in particular not more than 20% by weight and especially not more than 17% by weight. In these cases, enzyme nuclei can be coated particularly well without agglomeration of the particles.

The addition of a flow aid after the coating step can improve the flow properties of the product. Typical flow aids are silicic acids, for example the sipamerate products of the company Degussa or the Tixosil products of the company Rhodia, talc, stearates and tricalcium phosphate or salts such as magnesium sulfate, sodium sulfate or calcium carbonate. The flow aids are added, based on the total weight of the product, in an amount of 0.005 wt .-% to 5 wt .-% of the coated product. Preferred contents are from 0.1% by weight to 3% by weight and more preferably from 0.2% by weight to 1.5% by weight. It is understood that, in addition to the coating of the hydrophobic material, one or more, for example 1, 2 or 3, further coatings which consist of other materials, for example the polymer coatings taught in the prior art, can also be applied by the method according to the invention, as known, for example, from WO 01/00042, WO 03/059086 and WO 03/059087. It is essential to the invention that at least one coating consists of the previously defined hydrophobic materials, it being possible for this layer to be arranged as desired and, in particular, arranged directly on the enzyme-containing core.

The enzyme granules obtainable by the process according to the invention are distinguished by a particularly high stability, in particular a particularly high pelleting stability. Accordingly, the present invention relates to the enzyme granules obtainable by the process according to the invention.

The granulate particles of the enzyme granules obtainable according to the invention have, due to their production, an enzyme-containing core and at least one hydrophobic coating arranged on the surface of the core and consisting of the previously defined hydrophobic materials. In addition, the granules may also contain one or more, e.g. 1, 2 or 3 further coatings of other materials, wherein the coating of the hydrophobic material according to the invention are preferably arranged directly on the enzyme-containing core.

Without wishing to be limited to one theory, it may be assumed that the particular stability of the enzyme granules obtainable according to the invention is based on an interaction of the specific composition of the enzyme core with the special hydrophobic coating.

Accordingly, the invention relates in particular to enzyme granules for feedstuffs whose particles A) contain an enzyme-containing core having a water content below 15% by weight, frequently in the range from 1 to 12% by weight, in particular in the range from 3 to 10% by weight and especially in the range of 5 to 9% by weight, based on the weight of the enzyme-containing core, of i) 50 to 96.9% by weight, preferably 55 to 94.5% by weight and in particular 60 to 90% by weight % of at least one of the abovementioned solid organic carrier materials, ii) 0.1 to 20% by weight, preferably 0.2 to 10% by weight, in particular 0.3 to 5% by weight and especially 0.5 to 3% by weight, of at least one of the aforementioned water-soluble polymeric binders, iii) from 3 to 49.9% by weight, in particular from 5 to 49.7% by weight and especially from 10 to

40 wt .-%, at least one of the aforementioned enzymes, as well as iv) optionally at least one of the abovementioned stabilizing salts in an amount of preferably up to 10 wt .-%, for example 0.1 to 10 wt .-%, in particular 0.2 to 5 wt .-%, and especially 0.3 to 3 wt .-%, wherein the proportions by weight of i), ii) and iii) and optionally iv) are based on the non-aqueous constituents of the core; and

B) have at least one hydrophobic coating arranged on the surface of the core, comprising at least 70% by weight, in particular at least 80% and especially at least 90% by weight of the coating, of saturated fatty acids, the esters of saturated fatty acids or Mixtures of it exists.

The weight ratio of core to coating is generally in the range of 70:30 to 99: 1, preferably in the range of 75:25 to 98: 2, in particular in the range of 80:20 to 96: 4 and especially in the range of 85 : 15 to 95: 5.

The enzyme granules according to the invention typically have particle sizes (particle diameter) which largely correspond to those of the crude granulate, ie. the ratio of mean particle diameter of the granules according to the invention to the mean particle diameter of the raw granules will generally not exceed a value of 1, 1: 1 and in particular a value of 1, 09: 1. Accordingly, the enzyme granules according to the invention advantageously have an average particle size in the range from 100 to 2000 .mu.m, in particular in the range from 200 to 1500 .mu.m and especially in the range from 300 to 1000 .mu.m. The geometry of the granules is usually cylindrical with a diameter to length ratio of about 1: 1, 3 to 1: 3 and optionally rounded ends.

Particularly preferred enzyme granules contain as enzyme at least one phosphatase and in particular one of the aforementioned phytases.

Phytase-containing enzyme granules preferably have a phytase activity in the range from 1 × 10 ³ to 1 × 10 ⁵ FTU, in particular 5 × 10 ³ to 5 × 10 ⁴ FTU, and especially 1 × 10 ⁴ to 3 × 10 ⁴ FTU. 1 FTU phytase activity is defined as the amount of enzyme that liberates 1 micromole of inorganic phosphate per minute from 0.0051 mol / l aqueous sodium phytate at pH 5.5 and 37 ° C. The determination of the phytase activity can be carried out, for example, according to "Determination of Phytase Activity in Feed by a Colorimetric Enzymatic Method": Collaborative Interlaboratory Study Engelen et al .: Journal of AOAC International Vol. 84, no. 3, 2001, or Simple and Rapid Determination of Phytase Activity, Engelen et al., Journal of AOAC International, Vol. 3, 1994 be performed. Enzyme granules containing a plant cell wall degrading enzyme, eg a xylanase, typically have an enzyme activity in the range of 300 to 500,000, preferably 1,000 to 250,000, especially 1,500 to 100,000, more preferably 2,000 to 80,000 and especially 3,000 to 70,000 EXU / g.

Enzyme granules containing a cellulase, e.g. a glucanase such as a β-glucanase, typically have an enzyme activity in the range of 100 to 150,000, preferably 500 to 100,000, especially 750 to 50,000, more preferably 1000 to 10,000 and especially 1500 to 8000 BGU / g.

Endo-xylanase activity (EXU) is defined as the amount of enzyme that releases 1.00 micromoles of reducing sugars, measured as xylose equivalents, per minute at pH 3.5 and 40 ° C. A beta-glucanase unit (BGU) is defined as the amount of enzyme that releases 0.258 micromoles of reducing sugar, measured as glucose equivalents, per minute at pH 3.5 and 40 ° C. Endo-xylanase activity (EXU) and β-glucanase activity (BGU) can be determined according to Engelen et al., Journal of AOAC International Vol. 5, 1019 (1996).

Another object of the invention relates to feed compositions, in particular pelletized feed compositions containing in addition to conventional ingredients at least one feed additive according to the above definition as an admixture.

Finally, the invention also relates to the use of a feed additive as defined above for the production of feed compositions, in particular of hydrothermally treated and especially of pelleted feed compositions.

For the preparation of the feed compositions, the coated enzyme granules produced according to the invention are mixed with conventional animal feed (such as, for example, pig feed, piglet feed, sow feed, broiler feed and turkey feed). The enzyme granulate content is chosen so that the enzyme content z. B. is in the range of 10 to 1000 ppm. Then the feed is pelleted using a suitable pellet press. For this purpose, the feed mixture is conventionally conditioned by steam injection and then pressed through a die. Depending on the die pellets of about 2 to 8 mm in diameter can be produced. The highest process temperature occurs during conditioning or during pressing of the mixture through the die. Here, temperatures in the range of about 60 to 100 ⁰ C can be achieved.

Example 1 : a) In an aqueous phytase concentrate having a dry matter content of about 25 to 35 wt .-%, a pH in the range of 3.7-3.9 and an activity of 26000 to 36000 FTU / g was dissolved at 4-10 ° C 1 wt .-% zinc sulfate hexahydrate, based on the concentrate.

b) In a mixer with a chopper knife, 900 g of corn starch were prepared, homogenized and slowly added thereto at temperatures of 10 to 30 ° C. with homogenization while simultaneously 380 g of the zinc sulfate-containing phytase concentrate and 140 g of a 10% strength by weight solution of polyvinyl alcohol (degree of hydrolysis:

87-89%). The mixture was homogenized while cooling the mixer for a further 5 minutes at temperatures in the range of 10 to 50 ° C, then transferred the dough thus obtained in a dome extruder and extruded the dough at temperatures in the range of 30 to 50 ° C by a die with a Hole diameter of 0.7 mm to 5 cm long strands.

c) The extrudate thus obtained was in a rounding machine (type P50, Glatt company) for 5 min at 350 min ^"1 (rotational speed of the rotating plate) rounded and then in a fluidized bed dryer at a temperature of up to 40 ° C (product temperature) to a Residual moisture of about 6 wt .-% dried.

The raw granules thus obtained had an activity of about 14200 FTU / g. The granules had a maximum particle size of 1300 μm and an average particle size of 650 μm (sieve analysis).

d) For the subsequent coating, the raw granules were placed in a laboratory fluidized bed Aeromat type MP-1 from Niro-Aeromatic. As a reservoir, a plastic cone was used with a distributor plate diameter of 1 10 mm and a perforated bottom with 12% free area. The coating agent was a commercial saturated triglyceride

Ci ₆ / Ci ₈ fatty acids (melting point 57-61 ° C, iodine value 0.35, saponification number 192).

The crude granules charged into the fluidized bed (700 g) was heated with swirling with an airflow of 50 m ³ / h at 45 ⁰ C product temperature. 124 g of Trigly- cerids were melted in a beaker at 85 ⁰ C and sprayed onto the raw granules at 1 bar spraying pressure with heated spray gas of 80 to 90 ⁰ C by means of a two Unterdruckeinsaugung (1 mm) in the bottom spray method. During the spraying was the coating material and the intake to 80 to 90 ⁰ C heated to obtain a fine spray, so that a uniform coating layer formed around the particles and completely enveloped them. During the spraying process, the amount of air on 60 m ³ / h increased to keep the fluidized bed height. The spraying time was 15 min, the product temperature being 45 to 48 ⁰ C and the inlet air temperature was about 45 ⁰ C. Subsequently, the product was cooled to 30 ^° C. with vortexing at 50 m ³ / h supply air.

A product was obtained with the following characteristics:

Composition:

Corn starch 68.0% by weight Phytase (dry matter) 12.0% by weight

Polyvinyl alcohol: 1, 1 wt .-%

Zinc sulfate (ZnSO ₄ ): 0.4% by weight

Triglyceride: 15.0% by weight

Residual moisture: 3.5% by weight

Phytase activity: about 11,800 FTU / g

Appearance (microscope): particles with a smooth surface

Comparative Example V1:

In analogy to the procedure of Example 1, steps a) to c), a raw granulate was prepared. The crude granules thus obtained had a phytase activity of about 13,000 FTU / g and was then sprayed in the fluidized-bed apparatus according to example 1, step d) with a commercially available aqueous polyethylene dispersion (solids content 30% by weight, viscosity: 50%). 300 mPas, pH 9.5 - 1 1, 5)

For this purpose, the raw granules (700 g) were vortexed at room temperature with a supply air volume of 35 m ³ / h. The polyethylene dispersion was sprayed with a two-fluid nozzle (1, 2 mm) at a supply air temperature of 35 ⁰ C, supply air of 45 m ³ / h, at 1, 5 bar by pumping with a peristaltic pump on the enzyme granules. The product temperature during spraying was 30 to 50 ⁰ C. The dispersion was sprayed in the top spray on the enzyme granules. The water of the dispersion evaporated and the PE particles enveloped the granules and adhered to their surface (coating). During the spraying, the supply air quantity was gradually increased to 65 m ³ / h in order to maintain the turbulence. The spraying time was 15 min. Subsequently, the product was dried at 30 to 45 ⁰ C product temperature for 30 min, the supply air was lowered to 55 m ³ / h, in order to minimize abrasion of the coating shell.

A product was obtained with the following characteristics: Composition:

Corn starch 78.6% by weight Phytase (dry matter) 12.0% by weight

Polyvinyl alcohol: 1.4% by weight of zinc sulfate (ZnSO ₄ ): 0.5% by weight

Polyethylene: 4.0% by weight

Residual moisture: 3.5% by weight

Phytase activity: ca. 12530 FTU / g Appearance (microscope): particles with a smooth surface

Example 2:

a) In an aqueous phytase concentrate having a dry matter content of about 25-35 wt .-%, a pH in the range of 3.7-3.9 and an activity of

26000-36000 FTU / g were dissolved at 4-10 ° C 1 wt .-% zinc sulfate hexahydrate, based on the concentrate. Subsequently, by addition of 5% by weight, based on the phytase concentrate, of a 5% strength by weight aqueous ammonia solution, a pH of 5 was set.

b) + c) Using the neutralized phytase concentrate prepared in a), according to the procedure of Example 1, steps b) and c), a rounded raw granulate was prepared.

The raw granules thus obtained had an activity of about 13300FTU / g. The

Granules had a maximum particle size of 1300 μm and an average particle size of 645 μm (sieve analysis).

d) The crude granules thus obtained were then used in a laboratory fluidized bed Aero-type MP-1 from Niro-Aeromatic according to the procedure of Example 1,

Step d) coated. In the coating agent was a commercially available triglyceride based on saturated C ₆ / Cie fatty acids (melting point 57-61 ° C, iodine value 0.35, saponification value 192).

A product was obtained with the following characteristics:

Composition:

Corn starch 68.0% by weight

Phytase (dry matter) 12.0% by weight of polyvinyl alcohol: 1, 1% by weight

Zinc sulfate (ZnSO ₄ ): 0.4% by weight Triglyceride: 15.0% by weight Residual moisture content: 3.5% by weight

Phytase activity: approx. 11050 FTU / g Appearance (microscope): particles with a smooth surface

Example 3:

26000-36000 FTU / g were dissolved at 4-10 ° C 1 wt .-% zinc sulfate hexahydrate, based on the concentrate. The concentrate was heated to 30.degree. C. and 1, 1% by weight of methylcellulose (molecular weight of 70000-120000 g / mol, viscosity: 4600 cps at 2% by weight in water and 20.degree. C., degree of substitution 1) was heated , 6-1, 9) and stirred until the methylcellulose completely dissolved.

Subsequently, by adding 5 wt .-%, based on the phytase concentrate, a 5 wt .-% aqueous ammonia solution, a pH of 5 a.

b) 890 g of corn starch were placed in a mixer with chopper knife, homogenized and slowly added at temperatures of 10 to 30 ° C. with homogenization 433 g of the phytase concentrate from step a). The mixture was homogenized while cooling the mixer for a further 5 minutes at temperatures in the range of 10 to 50 ° C, then transferred the dough thus obtained in a dome extruder and extruded the dough at temperatures in the range of 30 to 50 ° C through a die with a hole diameter of 0.7 mm to 5 cm long strands.

c) The extrudate thus obtained was placed in a rounding machine (type P50, Glatt company) for 5 min. at 350 min ^"1 (speed of the plate) rounded and then dried in a fluidized bed dryer at a temperature of 40 ° C (product temperature) to a residual moisture content of about 6 wt .-%.

The raw granules thus obtained had an activity of about 12700 FTU / g. The granules had a maximum particle size of 1400 μm and a mean particle size of 662 μm (sieve analysis).

d) The raw granules thus obtained were then coated in a laboratory fluidized bed Aero-type MP-1 from Niro-Aeromatic according to the procedure of Example 1, step b). In the coating agent was a commercially available triglyceride based on saturated C ₆ / C ₈ fatty acids (melting point 57-61 ° C, iodine value 0.35, saponification number 192).

A product was obtained with the following characteristics:

Composition:

Corn starch 68.6% by weight Phytase (dry matter) 12.0% by weight

Methylcellulose: 0.5% by weight

Zinc sulfate (ZnSO ₄ ): 0.4% by weight triglyceride: 15.0% by weight

Residual moisture: 3.5% by weight

Phytase activity: about 10450 FTU / g

Appearance (microscope): particles with a smooth surface

Example 4:

The preparation was carried out analogously to Example 3, wherein, in contrast to the rule given there, no aqueous ammonia solution was added.

A product was obtained with the following characteristics:

Composition: corn starch 68.6% by weight

Phytase (dry matter) 12.0% by weight

Methylcellulose: 0.5% by weight,

Zinc sulfate (ZnSO ₄ ): 0.4% by weight

Triglyceride: 15.0% by weight Residual moisture content: 3.5% by weight

Phytase activity: about 10760 FTU / g

Appearance (microscope): particles with a smooth surface

Experiment 1: Determination of pelleting stability

To assess the pelleting stability of the enzyme granules described above, standard pelleting was determined. For this purpose, the dosage in the feed was increased to improve the analytical content. The pelleting was carried out so that a conditioning temperature of 80 to 85 ⁰ C was reached. Representative samples of the feed were obtained before and after pelleting. In These samples were determined for enzyme activity. Optionally, after correction for the level of enzyme present natively, the losses due to pelleting or the relative residual activity (= retention) can be calculated.

The method of analysis for phytase is described in several publications: Simple and Rapid Determination of Phytase Activity, Engelen et al., Journal of AOAC International, Vol. 3, 1994; Phytase Activity, General Tests and Assays, Food Chemicals Codex (FCC), IV, 1996, p. 808-810; Determination of Phytase Activity in Enzyme Standard Materials and Enzyme Preparations VDLUFA Method Book, Vol. IM, 4. Erg. 1997; or Determination of phytase activity in feed and premixtures VDLUFA Method Book, Volume IM, 4th ed. 1997th

The feed used was a broiler feed with the following composition:

Corn 45.5%

Soya meal 27.0%

Full fat soybeans 10,0%

Peas 5.0%

Tapioca 4.7%

Soybean oil 3.5%

Lime 1, 35%

Monocalcium phosphate 1, 30%

Cattle salt 0.35%

Vitamin / trace element premix 1, 00%

D, L-methionine 0.25%

L-lysine HCl 0.05%

100%

The coated granules prepared in the above examples were mixed with the above standard feed (proportion of 500 ppm), pelletized, and the samples obtained were analyzed. The relative improvement in the retention of the enzyme activity over the granules from Comparative Example C1 was calculated as follows: Ratio Retention of the enzyme activity of the improved granules to retention of the enzyme activity of the granules from Comparative Example C1. The results are summarized in Table 1 below.

Table 1: Achieved pelleting stability

PE = polyethylene PVA = polyvinyl alcohol MC = methylcellulose

Claims

claims:

A process for the preparation of solid enzyme granules for animal feed, comprising the following steps: a) extrusion of an enzyme-containing dough containing, in addition to water, i) 50 to 96.9% by weight of at least one solid carrier material suitable for animal feed, ii) 0.1 to 20% by weight of at least one water-soluble polymer

Binder, iii) contains from 3 to 49.9% by weight of at least one enzyme, the proportions by weight of i), ii) and iii) being based respectively on the nonaqueous constituents of the dough; b) preparing the extrudate into a raw granulate having a water content of not more than 15% by weight, and c) coating the raw granules with a hydrophobic material containing at least 70% by weight, based on the hydrophobic material, of saturated fatty acids , the esters of saturated fatty acids and mixtures thereof is selected.

2. The method of claim 1, wherein in step c) the raw granules with the hydrophobic material in an amount of 1 to 30 wt .-%, based on the non-aqueous constituents of the raw granules, coated.

3. The method of claim 1 or 2, wherein in step c) the hydrophobic material is used in the form of its melt.

4. The method according to any one of the preceding claims, wherein the hydrophobic material consists of at least 70 wt .-% of one or more triglycerides.

5. The method according to any one of the preceding claims, wherein in step b) the extrudate from step a) subjected to a spheronization and then dried to a raw granules having a residual water content of not more than 15 wt .-%, based on the total weight of the raw granules , to obtain.

6. The method according to any one of the preceding claims, wherein the raw granules obtained in step b) has an average particle size in the range of 100 to 2000 microns.

A process according to any one of the preceding claims, wherein the support material comprises at least one water insoluble polymeric carbohydrate.

8. The method according to any one of the preceding claims, wherein the water-soluble, polymeric binder is selected from polyvinyl alcohol and water-soluble polysaccharides.

The method of claim 8 wherein the water-soluble polymeric binder is methylcellulose.

10. The method according to any one of the preceding claims, wherein the enzyme is a phosphatase [E. C. 3.1.3], in particular a phytase.

A process according to any one of the preceding claims, wherein the dough used in step a) additionally contains an enzyme stabilizing salt in an amount of from 0.1 to 10% by weight, based on the total weight of all non-aqueous constituents of the dough.

12. The method of claim 11, wherein the salt is selected from zinc sulfate and magnesium sulfate.

13. Enzyme granules for animal feed, obtainable by a process according to one of claims 1 to 12.

14. Enzyme granules for feed, its particles

A) an enzyme-containing core having a water content of less than 15% by weight, based on the weight of the enzyme-containing core, of i) from 50 to 96.9% by weight of at least one solid support material suitable for animal feed, ii) from 0.1 to 20 Wt .-%, at least one water-soluble polymer

Iii) from 3 to 49.9% by weight of at least one enzyme, the proportions by weight of i), ii) and iii) being based on the non-aqueous constituents of the core, respectively; and

B) at least one disposed on the surface of the core hydrophobic coating, which consists of at least 70 wt .-%, based on the weight of the coating, of saturated fatty acids, the esters of saturated fatty acids or mixtures thereof.

15. Enzyme granules according to claim 14, wherein the weight ratio of core to coating is in the range from 70:30 to 99: 1.

16. Enzyme granules according to claim 14 or 15, wherein the hydrophobic coating consists of at least 70 wt .-% of one or more triglycerides.

17. Enzyme granules according to any one of claims 14 to 16, which has a mean particle size in the range of 100 to 2000 microns.

18. Enzyme granules according to any one of claims 14 to 17, wherein the carrier material comprises at least one water-insoluble polymeric carbohydrate.

19. Enzyme granules according to any one of claims 14 to 18, wherein the water-soluble, polymeric binder is selected from polyvinyl alcohol and water-soluble polysaccharides.

20. Enzyme granules according to claim 19, wherein the water-soluble, polymeric binder is methylcellulose.

21. Enzyme granules according to any one of claims 14 to 20, wherein the enzyme is a phosphatase [E. C. 3.1.3], in particular a phytase.

22. Enzyme granules according to any one of claims 14 to 21, wherein the core additionally contains an enzyme-stabilizing salt in an amount of 0.1 to 10% by weight, based on the total weight of all non-aqueous constituents of the core.

23. Enzyme granules according to claim 22, wherein the salt is selected from zinc sulfate and magnesium sulfate.

24. Use of an enzyme granulate according to any one of claims 13 to 23 in feeds.

25. Feed containing at least one enzyme granules according to any one of claims 13 to 23 and conventional feed ingredients.

26. Feed according to claim 25 in the form of a pelleted feed.