Coated vitamin C preparation for animal feed, production and use thereof

Abstract: A coated vitamin C preparation for animal feed, comprising a particulate core substance having a content of vitamin C and a coating material composed of one or more fine powdery lipids having a melting point of at least 40°C and a content of vitamin E, said coating material being present as an agglomerated coating layer surrounding the entire circumference of each particle of said particulate core substance. The coated vitamin C preparation is produced by a process, which comprises a step of bringing particles of a particulate core substance having a content of vitamin C into contact collidingly with particles of a coating material composed of one or more fine powdery lipids having a melting point of at least 40 °C and a content of vitamin E, so as to form a coating layer of agglomerated particles of the coating material surrounding the entire circumference of each particle of the core substance. The coated vitamin C preparation is useful as a supplement to feeds for animals, such as, livestock, poultry and marine animals, by admixing as such to the feed. The coated vitamin C preparation is superior, as compared with conventional coated preparations, in the coverage performance, vitamin C isolation effect against external influences of, such as, light, heat, moisture and atmosphere, to attain better preservation of the vitamin C activity even upon admixing to feed mixtures, with high adsorptibility of vitamin C by organisms.

Description: FIELD OF THE INVENTION The present invention relates to a coated vitamin C preparation for animal feed and a process for the production and use thereof. More particularly, the present invention relates to a coated vitamin C preparation for animal feed in a form of particles each having a core containing vitamin C coated by a layer of lipid, as well as to a process for the production and use thereof. BACKGROUND OF THE INVENTION Vitamin C has widely been incorporated in animal feeds as a vitamin C supplement and as an antioxidant. The physiological activity of vitamin C decreases on the influence of atmosphere and moisture and by the action of light, heat and co-existing substances, such as metal ions etc. Thus, the vitaminic effectivity thereof is apt to be destroyed easily. Under these circumstances, attempts had been made for providing a coated granular vitamin C preparation capable of attaining prevention of such activity decrease of vitamin C. The hitherto proposed methods for preparing coated or encapsulated products of water-soluble vitamins inclusive of vitamin C can be classified into the following two generalized ways: The first way comprises procedures of preparing an oil suspension of particulate product of water-soluble vitamin in a melt of a coating material composed of, such as, hardened oil, wax etc., spraying the resulting oil suspension using a spraying device or a rotary disc and solidifying the droplets formed upon the spraying by cooling, so as to form solid encapsulated particles of the water-soluble vitamin within a coverage layer of the coating material (See, for example, "Raw Feed Composition for Fish Cultivation" described in the Japanese Patent Publication No. 13192/1975, "Feeds for Fish Cultivation" given in the Japanese Patent Application Kokai No. 205461/1983 and so on). The second way consists in a so-called fluidized bed process which comprises procedures of forming a gaseous suspension of a particulate product of water-soluble vitamin in a pneumatically fluidized layer on a lifting wind blown up from the bottom of a fluidizing apparatus and spraying a solution of coating material, such as, a hardened fatty oil, wax etc., in a volatile solvent into the fluidizing layer as mist or liquid droplets from the side or upper portion of the fluidizing layer to effect coating of the vitamin particles and evaporating off the solvent to dry the coating layer, or similar procedures using a fluidizing apparatus (See, for example, "Process for Effecting Coating of Particulate Product of Vitamin" as given in the Japanese Patent Application Kokai No. 52221/1975). As to the coating material to be employed for producing coated or encapsulated particulate preparation of vitamins, there had been disclosed many researches, such as for example, "Method for Stabilizing L-Ascorbic Acid and its Salts" with the use of hardened fatty oils, lecithin and glycerin fatty acid monoesters, as given in the Japanese Patent Publication No. 16779/1981; "Feeds for Fish Cultivation" with the use of higher fatty acids, as disclosed in the Japanese Patent Application Kokai No. 205461/1983; "Thiamin Preparation for Fish Cultivation" with the use of waxes, as disclosed in the Japanese Patent Application Kokai No. 157020/1984 and so on. The conventional coated vitamin C preparations for animal feeds have disadvantages, such as for example, insufficient coverage performance, lower content of vitamin C in the preparation with concomitant necessity of large application rate, poor conservation of vitamin C activity, lower absorptibility of vitamin C by organisms and so on. On the other hand, it has been proposed a method for coating over the entire circumferential surface of each particle of a pulverous product of amino acids as core material with a layer of a powdery product of a lipid having a melting point of at least 40 °C as coating material by causing the particles of the coating material to adhere uniformly onto the surface of particle of the core material (Japanese Patent Application Kokai No. 2554/1989). If this method is applied to effect coating of particles of a pulverous vitamin C product, no coated vitamin C preparation exhibiting superior preservation of vitamin activity can be obtained. JP-A-63164863 discloses a preparation produced by coating a core substance of an organic acid or its salt with a particulate lipid as a coating material, over the entire surface of the core particle. The lipid may have a melting point of at least 40°C, the core substance a particle size of 1 µm to 1 mm, a particle size ratio of the core substance to the coating material (core particle size/coating particle size) of 1 to 1000, and a weight ratio of the core substance to the coating material of 0.5:1 to 50:1. In reference Example 1, the core substance is produced by adding 250 g of L-ascorbic acid to 1 kg of rapeseed oil. An object behind the present invention is to provide a coated vitamin C preparation for application to animal feeds, which provides high absorption of vitamin C by organisms and effective isolation of the vitamin C from external influences such as atmosphere, moisture, light and heat. SUMMARY OF THE INVENTION A vitamin preparation according to the present invention comprises a particulate core substance containing vitamin C and, entirely surrounding each core particle, a coating material layer of agglomerated particles of one or more finely particulate lipids having a melting point of at least 40°C; wherein the core substance comprises at least 10% by weight vitamin C, and the coating material comprises 0.5 to 10% by weight vitamin E. The novel preparation may be produced by bringing the vitamin C core substance particles into colliding contact with the coating material particles containing vitamin E, so as to form a coating layer by the coating material to enclose the vitamin C particle therein. The coated vitamin C preparation according to the present invention is utilized for supplementing feeds for livestock, poultry, marine culture animals by admixing it to the feeds. DETAILED DESCRIPTION OF THE INVENTION The particulate vitamin C product to be employed as the core substance of the coated vitamin C preparation according to the present invention may be either a product from natural material or a synthesized product existing in a form of powder or particles at ordinary temperature. The particulate vitamin C product may either be crystalline or amorphous. Such particulate vitamin C product can be utilized as such for the raw material of core substance of the coated preparation according to the present invention, while it is of course possible to incorporate a preliminary granulation or pre-coating of the particulate or powdery vitamin C product with other components, such as, water-soluble materials, fatty substances and so on, for use for the core substance. Concrete examples of the particulate vitamin C product include those of L-ascorbic acid, DL-ascorbic acid, araboascorbic acid, L-glucoascorbic acid, L-rhamnoascorbic acid and 6-desoxyascorbic acid; salts of these acids with metal cations, such as, calcium, sodium, potassium and so on; esters of these acids with, such as, phosphoric acid, acetic acid, sulfuric acid, fatty acids and derivatives, such as, metal salts etc., of these esters. These products can be employed solely or in combination of two or more of them for the core substance of the coated preparation according to the present invention. For the water-soluble componenets which can be employed for the above-mentioned preliminary granulation or pre-coating of the particulate vitamin C product, there may be enumerated, for example, sugars, proteins, amino acids, inorganic salts and so on. As the fatty substances, there may be employed various lipids, such as, natural fats and oils, hardened oils, waxes, fatty acid monoglycerides, fatty acid diglycerides, fatty acids. Other components which can be employed are organic and inorganic high molecular weight substances of natural or synthetic nature. The content of vitamin C in the starting particulate core substance should be at least 10 % by weight, preferably at least 50 % by weight. The particle size of the particulate starting core substance may be in the range from 0.1 to 1,000 µ m, preferably in the range from 10 to 700µ m. The coating material to be employed in the coated preparation according to the present invention may be a particulate lipid material having a melting point of at least 40°C and a content of vitamin E. As the lipid to be incorporated in the coated vitamin C preparation according to the present invention, there may be enumerated animal and vegetable oils, such as, soybean oil, palm oil, rapeseed oil, coconut oil, beaf tallow, lard and so on; oils produced by microorganisms; fatty acid esters, such as, fatty acid monoglycerides, fatty acid diglycerides, fatty acid propylene glycol esters and fatty acid sucrose esters; fatty acids and metal salts thereof; higher alcohols; waxes; phospholipids containing phosphrus and nitrogen; sugar lipids having sugar as the component; sulfolipids having sulfo group; sterols; hydrocarbons; antioxidants, such as, ethoxyquin (6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline), butyl hydroxyanisole, butyl hydroxytoluene, tert-butyl hydroquinone, oryzanol and spice extract; fat soluble vitamins, such as, vitamin A, vitamin K and so on; and hardened materials of these lipids. These lipids can be employed alone or in mixture of two or more of them . As the vitamin E component, products of either natural material and synthesized material can be employed, above all, α -, β -, γ - and δ -tocopherols, esters of these with acetic acid, nicotinic acid and succinic acid. They are used solely or in combination of one or more of them. The coating material to be employed in the coated vitamin C preparation according to the present invention is composed of fine powdery product of the above-mentioned lipid material having a melting point of at least 40°C with an addition of vitamin E component. The content of vitamin E in the coating material may be in the range from 0.5 to 10 %, preferably from 0.5 to 5 %, based on the weight of the fine powdery coating material. The particle size of the fine powdery coating material may be in the range from 0.1 to 100 µ m, preferably from 0.5 to 50 µ m. The restriction as to the melting point of the fine powdery coating material is due to the practical requirement for attaining coating over the core particle of vitamin C by a solid coverage layer of agglomerated particles of the fine powdery coating material at ordinary temperature. If the melting point is lower than 40°C, the solid discrete particulate state of the coated vitamin C preparation on storage at ordinary temperature will no longer be maintained. The coated vitamin C preparation for animal feed according to the present invention is thus composed of a particulate core substance essentially of, or containing, vitamin C coated around its entire circumference with a layer of the lipid fine powdery coating material, whereby the particulate core substance is isolated efficiently against external influences, such as ambient atmosphere etc. The coating layer is composed of an agglomerate of fine particles of the powdery lipid, which is distinguished from that of conventional preparations in which the coating layer is formed from a melt or solution of the coating material resulting in a successive filmy coverage layer. A suitable weight proportion of the particulate core substance to the powdery coating material may be in the range from 0.1 to 50, preferably from 1 to 5. A suitable ratio of particle size of the particulate core substance to that of the powdery lipid coating material may be in the range from 0.1 to 10,000, preferably from 10 to 500. The coated vitamin C preparation for animal feed according to the present invention is produced by causing the particles of the lipid fine powdery coating material having a melting point of at least 40 °C and a content of vitamin E to bring into contact with particles of the core substance under collision, to thereby form a coating layer of agglomerate of the particles of fine powdery coating material surrounding the entire circumference of each of the core particles. Upon collision of particles of the core substance with the fine particles of the coating material and the fine particles of the coating material with each other, the impinged portion of the fine particles of coating material will superficially be melted and the particles will fuse together, whereby a tight coating layer is built up. As compared with the film-like continuous coating layer of conventional coated preparation in which the thickness of the coating layer is extremely thin at sharp portions, such as, edges, pointing ends etc., of the core particle where the coating layer will tend to be broken to expose the core, coating layer of the coated vitamin C preparation according to the present invention formed by collision of the particles provides a complete coverage of such sharp edges of the core particle, since the coating is effected by integration of fine particles under agglomeration, which tends to form a rounded contour. For realizing contact of the fine particles of coating material with the particle of core substance under collision, various apparatuses can be utilized, such as, ball mill, electric mortar, high efficiency powder mixer, pnuematic high vortex apparatus and so on (hereinafter denoted as coating devices). Care must be paid here for not causing excessively vigorous condition to occur, in order to prevent crushing or collapse of the core particle upon collision. Thus, the collision of the particles may preferably be effected under such a mild condition, that the core particle will not be broken and will be coated with agglomerate of fine particles of the powdery coating material over the entire circumference of the core particle by partial melting of the collided fine particles with fusion with each other to form a tight integrated coating layer. Such a mild condition may be attained on a rotating mechanical coating device at a circumferential velocity not higher than 70 m/sec. Here, the temperature of the entire system of the coating device should not exceed above 40 °C. While it is possible to effect the colliding contact of the fine particles of coating material with the particle of core substance by supplying both the starting materials directly to a coating device, an increase in the coverage performance may be attained when both the starting materials are once subjected to a pre-mixing on a suitable device and the resulting pre-mixture is supplied to the coating device to effect the intrinsic contact under collision. A further increase in the coverage performance will be realized, when the coating material is supplied to the coating device in several aliquotes to realize the colliding contact in multiplex steps. The mixing ratio of the core substance to the coating material (core substance/coating material weight ratio) may usually be in a range from 0.1 to 50, which may preferably be adjusted in conjunction with the particle size ratio. If the particle size ratio of the core substance to the coating material is greater, the said mixing ratio can be settled at a high value, while the mixing ratio may preferably be settled at a low value if the paticle size ratio is smaller. However, the coverage performance will not simply be increased by selecting the mixing ratio at a lower level, but a better performance may in some cases be attained even with a greater mixing ratio. With a same mixing ratio, an increase in the coverage performance will be attained by effecting the coating process in several steps by supplying the coating material under division into two or more aliquotes. The coated vitamin C preparation according to the present invention is useful for supplementing animal feeds by admixing it to conventional feed components as such so as to be received by, such as, livestock, poultry and marine culture animals. The rate of application or admixing of the coated vitamin C preparation according to the present invention depends on each specific animal, condition of such animal and so on, while an application rate of 0.0001 - 5 %, calculated as pure substance of vitamin C, based on the total weight of the feed, as a general measure, may be practical. The coated vitamin C preparation according to the present invention is superior in the coverage performance, as compared with conventional coated preparations, for effectively isolating the vitamin C core particle from external influences of, such as, other components, radiant rays, heat, moisture and ambient atmosphere, providing efficient preservation of the physiological activity of vitamin C for longer period of time. The effectivity of each component in the preparation is not destroyed upon blunt mixing with other feed materials for application. The absorptibility of vitamin C of the preparation according to the present invention by animals is quite high. Thus, an efficient absorption of vitamin C by organisms can be attained. According to the present invention, it is possible to increase the content of vitamin C in the coated preparation, permitting thus decrease of rate of application, resulting in a lowering of the over-all feed cost. By the process for producing the coated vitamin C preparation according to the present invention, coated vitamin C preparation exhibiting excellent properties as described above can easily and efficiently be obtained. PREFERRED EMBODIMENTS OF THE INVENTION Below, the present invention will be described by way of Examples, in which values for per cent are those on weight basis. Example 1 470 g of hardened rapeseed oil and 30 g of a mixed tocopherol concentrate [ d-Mixed Tocopherols Concentrate 40 (trademark) of Eisai Co., Ltd. ] were melted together and mixed homogeneously and the mixture was cooled to solidify. The resulting solid mixture was crushed into fine powder to prepare a fine powdery coating material having a melting point of 67.2 °C and an average particle size of 10 µ m. 150 g of the above powdery coating material were supplied together with 350 g of a particulate product of L-ascorbic acid having an average particle size of 120µ m to a high efficiency powder mixer [ NARA Hybridization System (trademark) of NARA Machinery Co., Ltd.] and were worked up therein at a circumferential velocity of 13 m/sec at a water-cooling jacket temperature of 25 °C for 20 minutes. The resulting coated vitamin C preparation for animal feed was admixed to a kneaded feed for eel cultivation at an application rate of 1 %, calculated as pure L-ascorbic acid, based on the weight of the kneaded feed, and the mixture was served for cultivation of eel, while observing the L-ascorbic acid level in the blood of eel during cultivation, in order to assess the absorptibility of L-ascorbic acid by the eel. The mixed kneaded feed prepared as above was administered to 10 eels by injecting the feed using a catheter into the stomach of each eel in an amount of 10 grams per 1 kilogram of the eel body weight and the ascorbic acid level in the blood was observed in the course of cultivation. Results are summarized in Table 1. Comparison Example 1 500 g of hardened rapeseed oil were solidified and crushed into fine powder to prepare a fine powdery coating material having a melting point of 67.3 °C and an average particle size of 10 µ m. Using this coating material, a coated vitamin C preparation was produced in the same manner as in Example 1 and a similar absorptibility tests were carried out on eel with it. Results are also given in Table 1. From Table 1, it is clear that the absorptibility of vitamin C by eel is better as compared with the coated preparation of Comparison Example 1. Example 2 920 g of hardened soybean oil, 50 g of palm oil and 30 g of dl-α -tocopherol were melted together to form a homogeneous mixture. This mixture was cooled to solidify and the solid mixture was crushed into powder to prepare a fine powdery coating material having a melting point of 64.8 °C and an average particle size of 10µ m. 300 g of the above fine powdery coating material were supplied to a Henschel Mixer together with 700 g of a particulate product of L-ascorbic acid having an average particle size of 120µ m to work up at a circumferential velocity of 30 m/sec at a cooling jacket temperature of 20 °C for 15 minutes. The thus obtained coated vitamin C preparation for animal feed was admixed to a kneaded feed for cultivating eel in an addition rate of 5 %, calculated as pure L-ascorbic acid, based on the weight of the kneaded feed. Using this mixed feed, eels were cultivated and the L-ascorbic acid level in the blood of eel was observed in the same manner as in Example 1. Results are also given in Table 2. Comparison Example 2 300 g of L-ascorbic acid were suspended in a fluidizing layer on a pneumatic fluidized bed granulator at a lifting wind temperature of 20 - 25°C at a flow rate of 0.2 m³/min and, into the fluidizing layer thus formed, 200 g of a melt of hardened beaf tallow were sprayed at a rate of 20 ml/min to obtain a coated L-ascorbic acid preparation. Using this coated preparation, L-ascorbic acid absorptibility tests were carried out on eel in the same manner as in Example 2. Results are recited also in Table 2. From the results of Table 2, it is confirmed that the absorptibility of vitamin C is superior for the coated vitamin C preparation of the present invention as compared with that of Comparison Example 2 on eel. While the difference in the absorptibility seems to be not highly distinguishable, the effect over the retention duration is large for the coated preparation of the present invention. Example 3 0.5 g of the coated vitamin C preparation obtained in Example 2 was mixed with 225 g of wheat flour, 269.5 g of fish meal, 2.5 g of mineral components and 2.5 g of choline chloride and the mixture was treated using a Brabender Extruder at a barrel temperature of 80°C with a water addition rate of 5 %, in order to produce pelletized feed. The residual proportion of L-ascorbic acid (weight % remained) in the thus obtained pellet is given in Table 3. Comparison Example 3 The coated preparation obtained in Comparison Example 2 was worked up into pellets under the same condition as in Example 3, whereupon the residual proportion of L-ascorbic acid in the pellet obtained was determined. Result is given in Table 3. From the result of Table 3, it is recognized that the vitamin C preservation effect is higher for the preparation of the present invention than that of Comparison Example 3. Example 4 The coated vitamin C preparation obtained in Example 2 was admixed, at an additon rate of 0.1 %, calculated as pure L-ascorbic acid, to a raw feed of mixer-minced raw sardine, whereupon the "strengthened" feed was stored at room temperature. The vitamin C content in the stored feed remaining in the course of storage was observed at intervals. Results are given in Table 4. Comparison Example 4 Calcium L-ascorbate was admixed, at an addition rate of 0.1 %, calculated as pure L-ascorbic acid, to the same feed employed in Example 4 and preservation of L-ascorbate was observed in the same manner as in Example 4. Results are also given in Table 4. Comparison Example 5 The coated vitamin C preparation obtained in Comparison Example 2 was admixed, at an addition rate of 0.1 %, calculated as pure L-ascorbic acid, to the same feed employed in Example 4 and preservation of L-ascorbic acid was observed in the same manner as in Example 4. Results are also given in Table 4. Comparison Example 6 In a melt of mixed oil (melting point 55°C ) composed of 360 g of hardened rapeseed oil and 840 g of hardened palm oil, 800 g of powdery L-ascorbic acid milled on a crusher to a particle size of below 20µ m were suspended. This oil suspension was sprayed into a cold wind to form a coated pulverous preparation having a vitamin C content of 40 %. Using this preparation, the same preservation tests as in Example 4 were carried out on the same feed. Results are given in Table 4. Example 5 The coated vitamin C preparation obtained in Example 2 was admixed, at an addition rate of 0.1 %, calculated as pure L-ascorbic acid, to a starting mass for moist pellet composed of 5 : 5 mixture of a raw feed of mixer minced raw asrdine and a composite feed composed of 54 % of fish meal, 45 % of wheat flour, 0.5 % of mineral components and 0.5 % of choline chloride, whereupon the "strengthened" feed was stored at room temperature. The vitamin C content in the stored feed remaining in the course of storage was observed at intervals. Results are given in Table 5. Comparison Example 7 Calcium L-ascorbate was admixed, at an addition rate of 0.1 %, calculated as pure L-ascorbic acid, to the same feed employed in Example 5 and preservation of L-ascorbate was observed in the same manner as in Example 5. Results are also given in Table 5. Comparison Example 8 The coated vitamin C preparation obtained in Comparison Example 2 was admixed, at an addition rate of 0.1 %, calculated as pure L-ascorbic acid, to the same feed employed in Example 5 and preservation of L-ascorbic acid was observed in the same manner as in Example 5. Results are also given in Table 5. From the results of Tables 4 and 5, it is seen that the coated vitamin C preparation according to the present invention exhibits an increased stability of vitamin C than the stabilized derivative of L-ascorbic acid (Ca L-ascorbate) and than the preparation obtained by a conventional method.

Claims: A vitamin preparation, comprising a particulate core substance containing vitamin C and, entirely surrounding each core particle, a coating material layer of agglomerated particles of one or more finely particulate lipids having a melting point of at least 40°C; characterised in that the core substance comprises at least 10% by weight vitamin C, and in that the coating material comprises 0.5 to 10% by weight vitamin E. A preparation as claimed in claim 1, wherein the weight ratio of the core substance to the coating material is from 0.1:1 to 50:1. A preparation as claimed in claim 1 or claim 2, wherein the core substance has a particle size of 0.1 to 1000 µm. A preparation as claimed in any preceding claim, wherein the coating material has a particle size of 0.1 to 100 µm. A process for producing a preparation as claimed in any preceding claim, comprising contacting the respective particles of the core substance and of the coating material. An animal feed composition additionally comprising a preparation as claimed in any of claims 1 to 4. A method for cultivating animals selected from livestock, poultry and marine animals, comprising feeding the animals with a preparation as claimed in any of claims 1 to 4.

Inventors: HISAMOTO TAKAAKI, IWANAMI KOICHI, KUBOTA SABUROH, HISAMOTO, TAKAAKI, IWANAMI, KOICHI, KUBOTA, SABUROH
Applicants: EISAI CO LTD, NIPPON OILS & FATS CO LTD, EISAI CO., LTD., NIPPON OIL AND FATS COMPANY, LIMITED
Application year: 1991
Main classification: A23K1
IPC codes: A61K31, A23K1, A61K9