Method for producing feed composition

Abstract

To provide a production method for producing a feed composition, the method having high general versatility, capable of achieving efficient workability, and improving a formation rate of fatty acid calcium, and the feed composition having a high content of fatty acid calcium.SOLUTION: A production method of a feed composition that includes fatty acid calcium includes: an enzyme decomposition step (S1) of enzyme decomposing triglyceride after mixing the triglyceride including unsaturated fatty acid as constituent fatty acid and lipase in the presence of water; a salt formation step (S2) of forming fatty acid calcium by adding and mixing calcium hydroxide to the decomposed matter obtained in the enzyme decomposition step (S1); and a solidification step (S5). The salt formation step (S2) is a step of heating the mixture at a temperature near the melting point of fatty acid calcium. The solidification step (S5) is a step of discharging the processed matter in a half-molten state after the salt formation step (S2) and cooling the processed matter to be solidified.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a feed composition containing fatty acid calcium. [Background technology]

[0002] Conventionally, feed compositions containing triglycerides, fatty acids, etc. have been widely used in feeds for livestock animals such as cows and pigs. These are formulated for the purpose of efficiently supplying energy, and fatty acid calcium, a metal salt of fatty acid, is primarily formulated for dairy cows to suppress the decline in milk fat in the summer. Furthermore, fatty acid calcium containing n-3 fatty acids, which uses linseed oil or other raw oils, is formulated into feed for the purpose of improving the quality of meat (beef, pigs, chickens, etc.) and eggs by transferring the n-3 fatty acids. For example, fatty acid calcium is premixed into feed by a feed company or added to each feed at each livestock farm immediately before feeding.

[0003] Patent Document 1 proposes a production technology for a feed composition containing fatty acid calcium. Patent Document 1 describes a method for producing the feed composition, which includes the steps of mixing a triglyceride mainly composed of unsaturated fatty acids, calcium hydroxide, water, caramel having antioxidant properties, and lipase, and reacting the mixture at a temperature of 60°C or less to produce a composition containing fatty acid calcium. It also describes that this method produces a feed composition with high oxidation stability and excellent odor and palatability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-108076 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, fatty acid calcium is obtained by an enzymatic hydrolysis method using lipase, an enzyme that hydrolyzes fats and oils. In such enzymatic hydrolysis methods, the hydrolysis efficiency is affected by factors such as the type of lipase, resulting in different yields of fatty acid calcium. In Patent Document 1, the enzymatic hydrolysis is carried out under alkaline conditions, which limits the lipases that can be used, and this may affect the hydrolysis efficiency. In addition, alkaline lipases are relatively expensive, and there is room for improvement in terms of versatility.

[0006] In addition, in the manufacturing method of Patent Document 1, raw materials including triglyceride, calcium hydroxide, antioxidant caramel, and lipase are mixed for about 30 minutes, and then transferred to a separate container when the viscosity increases. In the separate container, an enzymatic decomposition reaction of the oil and fat and a reaction to produce fatty acid calcium are carried out for about 30 hours, resulting in solidification. The solidified material is then removed from the container and crushed to obtain fatty acid calcium. However, this method is thought to have room for improvement in terms of workability.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a method for producing a feed composition containing a high content of fatty acid calcium, which is highly versatile, has high workability, and can improve the production rate of fatty acid calcium. [Means for solving the problem]

[0008] The method for producing a feed composition of the present invention is a method for producing a feed composition containing fatty acid calcium, and comprises an enzymatic decomposition step in which triglycerides containing unsaturated fatty acids as constituent fatty acids are mixed with lipase in the presence of water to enzymatically decompose the triglycerides; a salt production step in which calcium hydroxide is added to and mixed with the decomposition product obtained in the enzymatic decomposition step to produce fatty acid calcium; and a solidification step, wherein the salt production step is a step of heating at a temperature near the melting point of the fatty acid calcium, and the solidification step is a step of discharging the semi-molten treated product after the salt production step and cooling it to solidify it.

[0009] The enzymatic decomposition step is characterized by being carried out at 30°C to 50°C for 2 hours or more.

[0010] The salt production step is characterized by being a step of stirring the fatty acid calcium salt at a temperature near the melting point of the fatty acid calcium salt for one hour or less.

[0011] The triglyceride is characterized in that the content of n-3 fatty acids is 50% by mass or more relative to the total constituent fatty acids. [Effects of the Invention]

[0012] The method for producing a feed composition of the present invention comprises an enzymatic hydrolysis step in which triglycerides containing unsaturated fatty acids as constituent fatty acids are mixed with lipase in the presence of water to enzymatically hydrolyze the triglycerides, and a salt production step in which the hydrolysis product is mixed with calcium hydroxide to produce fatty acid calcium.The enzymatic hydrolysis step can be carried out under neutral conditions, and there are few restrictions on the type of lipase, allowing the use of a lipase that is highly versatile and suitable for the hydrolysis efficiency of triglycerides.As a result, the production rate of fatty acid calcium can be improved, and a feed composition containing a high content of fatty acid calcium can be obtained.

[0013] Furthermore, the salt production step involves heating at a temperature near the melting point of fatty acid calcium salt, causing the fatty acid (including water) after enzymatic decomposition to react with calcium hydroxide, producing fatty acid calcium salt in a semi-molten state, so that the reaction for producing fatty acid calcium salt can be completed quickly (for example, within one hour), thereby improving work efficiency.

[0014] The enzymatic decomposition step is carried out at 30°C to 50°C for 2 hours or more, which promotes lipase activity and ensures more reliable enzymatic decomposition.

[0015] The lipase is a position-nonspecific lipase for triglycerides, and can randomly hydrolyze ester bonds in triglycerides, thereby improving the production rate of free fatty acids including unsaturated fatty acids (for example, the production rate of free fatty acids in the oil layer after lipase hydrolysis is about 95 to 97%). In addition, position-nonspecific lipases are generally cheaper than alkaline lipases, and can reduce costs. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a flow chart showing an example of a method for producing a feed composition of the present invention. [Figure 2] FIG. 1 is a flow chart showing another example of the method for producing a feed composition of the present invention. [Figure 3] 1 shows photographs of the appearance of feed compositions of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0017] The method for producing a feed composition of the present invention will be explained with reference to Figure 1. Figure 1 is a flow diagram showing an example of the method for producing a feed composition of the present invention. The production method shown in Figure 1 comprises an enzymatic decomposition step (S1), a salt production step (S2), a solid-liquid separation step (S3), and an antioxidant step (S4). The feed composition obtained by this production method is used as feed for livestock animals, etc. Each step will be explained in detail below.

[0018] [Enzyme degradation process (S1)] This process involves enzymatically hydrolyzing triglycerides using lipase. The triglycerides used as the raw oil or fat may contain at least one unsaturated fatty acid. Examples of unsaturated fatty acids include oleic acid, linoleic acid, α-linolenic acid, bishomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Examples of raw oils or fats containing these unsaturated fatty acids include linseed oil, soybean oil, rapeseed oil, corn oil, perilla oil, fish oil, and green nut oil, which can be used alone or in combination.

[0019] The raw material fats and oils preferably contain n-3 fatty acids such as α-linolenic acid, EPA, and DHA in an amount of 50% by mass or more relative to the total amount of constituent fatty acids, and more preferably contain α-linolenic acid in an amount of 50% by mass or more relative to the total amount of constituent fatty acids. Specific examples of such raw material fats and oils include linseed oil and perilla oil.

[0020] From another perspective, the mass ratio of n-3 fatty acids to n-6 fatty acids (n-3 fatty acids / n-6 fatty acids) in the constituent fatty acids of the raw material oil or fat is preferably 1 to 10, more preferably 2 to 6.

[0021] Linseed oil is a vegetable oil extracted from linseed, the seed of flax (Linum usitatissimum). After extraction from linseed, linseed oil is degummed, deacidified, bleached, etc. to remove moisture, gums, free fatty acids, color components, etc., and is commercially available. Such commercially available products can be used as the raw material oil. Deodorized linseed oil may also be used as the linseed oil.

[0022] The lipase used in step S1 is not particularly limited, and lipases derived from animals, plants, or microorganisms can be used. For example, lipases derived from the genera Candida, Aspergillus, Mucor, Pseudomonas, and Burkholderia can be used. Regarding the positional specificity of triglycerides, lipases are classified into 1,3-specific lipases and position-nonspecific lipases. Commercially available 1,3-specific lipases include, for example, Lipase AK "Amano" (manufactured by Amano Enzyme Co., Ltd., derived from Pseudomonas fluorescens), Lipase AS "Amano" (manufactured by Amano Enzyme Co., Ltd., derived from Aspergillus niger), Lipase PL (manufactured by Meito Sangyo Co., Ltd., derived from Pseudomonas pseudoalcaligenes), and Lipase QLM (manufactured by Meito Sangyo Co., Ltd., derived from Burkholderia ubonensis).

[0023] In the present invention, from the viewpoint of hydrolysis efficiency, it is preferable to use a position-nonspecific lipase, i.e., a lipase that can randomly hydrolyze ester bonds in triglycerides. Such position-nonspecific lipases are easily inactivated in alkaline conditions. Specifically, lipases originating from the genus Candida are preferred as position-nonspecific lipases, and commercially available products include, for example, Lipase OF (manufactured by Meito Sangyo Co., Ltd., originating from Candida cylindracea) and Lipase AYS "Amano" (manufactured by Amano Enzyme Co., Ltd., originating from Candida rugosa).

[0024] The amount of lipase added in step S1 is appropriately determined depending on the activity of the lipase, for example, a lipase with a titer of 100 U to 1000 U is added per 1 g of the raw material oil or fat, and preferably 300 U to 1000 U. Note that the lipase is, for example, dissolved in water while kneading to prepare a lipase solution, and the lipase solution is added to the raw material oil or fat while stirring.

[0025] The amount of water added in step S1 (including water in the lipase solution) is, for example, 0.5 to 5 times the weight of the raw material fat or oil. Considering the hydrolysis efficiency and handling in subsequent steps, the amount of water added is preferably 0.5 to 3 times, and more preferably 0.5 to 2 times the weight of the raw material fat or oil.

[0026] Step S1 is preferably carried out at 30°C to 60°C. This temperature range is excellent in terms of lipase reaction temperature, activity, thermal stability, etc., and high effectiveness can be expected. More preferably, it is 30°C to 50°C, and even more preferably 30°C to 45°C. The heating time in step S1 is preferably 2 hours or more, more preferably 4 hours or more, to complete enzymatic hydrolysis. When using raw oils and fats with a high content of unsaturated fatty acids, the upper limit of the heating time at 30°C to 45°C is preferably about 10 hours from the viewpoint of preventing oxidation. After the end of the heating time, the reaction may be continued for a predetermined period of time without heating, if necessary.

[0027] In step S1, an antioxidant may be added as needed to suppress oxidation of unsaturated fatty acid residues in the raw oil or fat. Examples of antioxidants include ethoxyquin, dibutylhydroxytoluene (BHT), and butylhydroxyanisole (BHA). These may be used alone or in combination of two or more.

[0028] [Salt production process (S2)] This step is a step of producing fatty acid calcium using calcium hydroxide. For example, the reaction solution after step S1 is added to another reaction vessel containing calcium hydroxide and water while stirring. Water may be used as needed, and when used, the amount used is, for example, 2 to 10 times the weight of the raw material fat or oil. After the entire reaction solution after step S1 is added, the mixture is stirred at room temperature (e.g., 25°C) for 10 minutes or more, preferably 1 hour or more. This step differs from the above-mentioned step S1 in that heat is not intentionally applied. The free fatty acids produced in step S1 react with calcium hydroxide, and fatty acid calcium particles precipitate as a solid.

[0029] The molar ratio of calcium hydroxide used in step S2 is not particularly limited, but is preferably 1.2 to 2.0, more preferably 1.3 to 1.8, relative to the raw oil / fat. For example, when linseed oil is used as the raw oil / fat, the molar ratio of calcium hydroxide is calculated based on the molar ratio obtained from the molecular weight of triglyceride (molecular weight 872) calculated based on the composition of constituent fatty acids of the linseed oil and the weight of linseed oil used.

[0030] [Solid-liquid separation process (S3)] This step is a step of separating solid matter from the treated product after step S2. Well-known solid-liquid separation methods can be used for solid-liquid separation, such as mesh filtration, suction filtration, and centrifugation. For example, when mesh filtration is performed, it is preferable to use a sieve with a mesh size of 32 mesh (opening size 50 μm) to 100 mesh (opening size 154 μm). The separated liquid is then pH-adjusted and disposed of as waste liquid.

[0031] The solid obtained by solid-liquid separation may be used as is in the subsequent step S4, or may be dehydrated, if necessary, to reduce the moisture content of the solid to a predetermined value or less. For example, the moisture content of the solid separated by mesh filtration is about 40% by mass, and this solid is dehydrated to a moisture content of 10% to 30% by mass. A lower moisture content is preferred to minimize foaming during vacuum drying in the subsequent oxidation prevention step. However, the moisture content is set to, for example, 10% by mass or more to facilitate the affinity of the antioxidant caramel to the fatty acid calcium particles and to allow the caramel to be mixed uniformly. The moisture content of the solid after dehydration is preferably 20% to 30% by mass.

[0032] From the viewpoint of preventing oxidation, the dehydration treatment is preferably carried out under conditions in which the product temperature is maintained at 40°C or less, preferably 25°C to 35°C. The dehydration treatment may be carried out using various drying devices, suction filtration, centrifugation, or the like. For example, when using a reduced-pressure drying device such as an evaporator, the dehydration is carried out at a reduced pressure of 10 Torr to 50 Torr and a heating temperature (water bath temperature) of 50°C to 90°C. Alternatively, drying may be carried out by heating using a conduction heat transfer type rotary dryer such as a double cone dryer. Note that the above dehydration treatment may involve a combination of several methods. For example, centrifugation may be followed by drying using a double cone dryer.

[0033] The moisture content of the solid matter can be calculated by the loss on drying method (method listed in the Feed Analysis Standards). The dehydration treatment is completed based on the calculated moisture content.

[0034] When, instead of mesh filtration, suction filtration or centrifugation is used as a means of solid-liquid separation, the treatment can be continued while separating the solid matter until the water content of the solid matter reaches 30 mass% or less, as in the above-mentioned numerical range.

[0035] [Anti-oxidation process (S4)] This step involves mixing and stirring the solid material separated in step S3 with antioxidant caramel to obtain a feed composition. Antioxidant caramel is a caramel with antioxidant properties that can be obtained, for example, by heating an aqueous solution of pentose or hexose monosaccharides in the presence of a basic compound under specific conditions. When adding the antioxidant caramel to the solid material, it is preferable to heat the antioxidant caramel to about 40°C in advance to make it fluid before adding it.

[0036] The amount of antioxidant caramel added is preferably 1% by mass to 10% by mass, more preferably 4% by mass to 10% by mass, based on the weight of fatty acid calcium. The weight of fatty acid calcium can be determined, for example, by calculating the moisture content of the dehydrated solid material after step S3 using the loss on drying method (method listed in the Feed Analysis Standards), and then subtracting the moisture content from the weight of the solid material.

[0037] Examples of monosaccharides used as raw materials for antioxidant caramel include glucose, xylose, galactose, and fructose. Among these, glucose is preferred because it is easily available and inexpensive. Examples of basic compounds include alkali metal carbonates such as sodium carbonate and potassium carbonate, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal bicarbonates such as sodium bicarbonate and potassium bicarbonate, sodium salts and ammonium salts of organic acids such as acetic acid and citric acid, and ammonium hydroxide. The antioxidant caramel used in the present invention is preferably caramel obtained by heat-treating glucose and sodium carbonate.

[0038] Antioxidant caramel can be obtained, for example, by heating 100 parts by mass of a 75% to 95% by mass aqueous solution of monosaccharides in the presence of 1 to 10 parts by mass of a basic compound for about 1 to 10 hours. The heating temperature is preferably 100°C or higher, more preferably 120 to 150°C. The pH of the obtained caramel is preferably 5 or lower.

[0039] The antioxidant properties of the resulting caramel can be evaluated, for example, by the following method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). First, a predetermined amount of the caramel is dissolved in ethanol, to which a 0.5 mM ethanol solution of DPPH is added, and the mixture is incubated at 37°C for 30 minutes. The absorbance at 517 nm is then measured, and a regression line is created between the amount of caramel and the amount of absorbance reduction due to the addition of caramel. The amount of absorbance reduction per 1 mg of caramel is calculated from this regression line, and this value can be used to evaluate the antioxidant properties of the caramel. This value is preferably 0.6 to 1.1.

[0040] In step S4, mixing of the solid material and antioxidant caramel and drying of the processed product may be carried out simultaneously. For example, mixing and stirring can be carried out under a predetermined reduced pressure and a predetermined temperature. In this case, it is preferable to carry out the process under conditions where the product temperature is maintained at 40°C or less, preferably 25°C to 35°C. The reduced pressure is preferably 10 Torr to 50 Torr, and the heating temperature is preferably 50°C to 90°C.

[0041] In step S4, mixing and drying may be performed separately rather than simultaneously. In this case, the solid material and antioxidant caramel are mixed at room temperature (e.g., 25°C) without heating. The subsequent drying is performed under reduced pressure so that the product temperature can be maintained at 40°C or below. For example, drying is performed at a reduced pressure of 10 to 50 Torr and a heating temperature of 50 to 90°C.

[0042] The drying in step S4 is carried out until the moisture content of the treated product reaches a predetermined moisture content (for example, 13.5% by mass). The feed composition obtained by drying may be pulverized into powder using a hammer mill or other pulverizer, if necessary.

[0043] In the manufacturing method of Figure 1, a preferred embodiment of steps S3 and S4 is a solid-liquid separation step (S3) in which solid-liquid separation is first performed to obtain a solid (moisture content: approximately 40% by mass), and then the solid is dehydrated using a centrifuge or an evaporator to reduce the moisture content to 10% to 30% by mass, and then in the anti-oxidation step (S4), antioxidant caramel is added and the solid is further dried to reduce the moisture content to 10% to 13.5% by mass. In this case, the solid-liquid separation step includes a dehydration treatment, and the anti-oxidation step includes a drying step.

[0044] A specific example of the preferred embodiment is shown below. The fatty acid calcium produced in the salt production step (S2) is charged into a double cone while still containing water. This double cone is fitted with a mesh at its outlet, which performs solid-liquid separation and dehydration (drying). First, solids are separated by solid-liquid separation using the mesh, and then the solids are dried in the double cone. Then, when the solids have been dried to a moisture content of 10% to 30% by mass, antioxidant caramel is added through a nozzle while the double cone is rotated without releasing the vacuum. The caramel is mixed with the fatty acid calcium particles and dried until the moisture content reaches 10% to 13.5% by mass. By performing steps S3 and S4 in this sequence, workability can be further improved.

[0045] Figure 2 is a flow chart showing another example of the method for producing a feed composition of the present invention. The production method shown in Figure 2 comprises an enzymatic decomposition step (S1), a salt production step (S2'), a solidification step (S5), and a pulverization step (S6). Each step will be explained below. Note that the enzymatic decomposition step (S1) is the same as the enzymatic decomposition step in Figure 1 above, and therefore its explanation will be omitted.

[0046] [Salt production step (S2')] This step is a step of producing fatty acid calcium using calcium hydroxide. For example, the oil layer (containing water) of the reaction solution from step S1 is transferred to another reaction vessel, and calcium hydroxide, water, and antioxidant caramel are added thereto with stirring. Water may be used as needed, and when used, the amount used is, for example, 0.001 to 1.0 times the weight of the raw material fat or oil. The molar ratio of calcium hydroxide used in this step, the amount of antioxidant caramel added, and the antioxidant properties of the antioxidant caramel can be appropriately adjusted within the above-mentioned numerical ranges. After calcium hydroxide, water, and antioxidant caramel are added to the oil layer (containing water) of the reaction solution from step S1, the mixture is stirred for 1 hour or less, preferably 10 to 30 minutes, at a temperature near the melting point of the fatty acid calcium, for example.

[0047] Step S2' differs from step S2 in the production method shown in FIG. 1 above in that step S2 is carried out under specific heating conditions. The temperature near the melting point of the fatty acid calcium is, for example, within a range of ±30°C of the melting point of the fatty acid calcium. This fatty acid calcium refers to at least one of the fatty acid calciums derived from the constituent fatty acids of the raw fat or oil. For example, when linseed oil is used as the raw fat or oil, step S2' is carried out by heating at 70°C to 200°C. More preferably, it is carried out by heating at 90°C to 160°C. By carrying out the reaction in the presence of a small amount of water while controlling the reaction temperature, fatty acid calcium can be produced in a semi-molten state, and the reaction can be completed quickly.

[0048] [Solidification process (S5)] The processed product after step S2' is taken out into another container and cooled to solidify, for example, by leaving it to stand at room temperature for 1 to 15 hours. In the conventional technology, the enzymatic hydrolysis reaction of fats and oils and the reaction to produce fatty acid calcium are carried out in separate containers, and the containers are left to stand for a long period of time (approximately 30 hours). In contrast, in the manufacturing method of Figure 2, the enzymatic hydrolysis reaction of fats and oils and the reaction to produce fatty acid calcium are completed in stages before step S5, and step S5 is carried out to solidify the semi-molten fatty acid calcium. In other words, the conventional technology and the manufacturing method of Figure 2 have different purposes after transferring the mixture to a separate container. As a result, the standing time in step S5 can be shorter than the standing time in the conventional technology (approximately 30 hours), improving work efficiency.

[0049] [Crushing process (S6)] The solidified material obtained in step S5 is pulverized into powder using a hammer mill or other pulverizing device.

[0050] In the production method of the present invention, in addition to the raw material oil / fat, lipase, calcium hydroxide, water, and antioxidant caramel, other additives may be added as appropriate, such as a palatability improver such as molasses, an emulsifier such as glycerin fatty acid ester, an anti-mold agent such as propionic acid, a sweetener such as saccharin sodium, and a flavoring.

[0051] The feed composition obtained by the above production method can be fed to livestock animals as is or mixed with other feed compositions to form feed. The obtained feed composition preferably contains fatty acid calcium in an amount of 52% by mass or more, more preferably 55% by mass or more, based on the total amount of the composition.

[0052] The resulting feed composition also has excellent oxidation stability: the peroxide value (POV) of the feed composition immediately after production is 5 or less, preferably 3 or less, and more preferably 1 or less. [Example]

[0053] Example 1 600 g of deodorized linseed oil was added to a reactor, and a lipase solution prepared by dispersing 345 U of Lipase OF (manufactured by Meito Sangyo Co., Ltd.) in 420 g of water (0.7 times the weight of linseed oil) per 1 g of linseed oil was added to the reactor with stirring, and the mixture was stirred at 40°C for at least 6 hours. In a separate reactor, 1634 g of water and 81.58 g of calcium hydroxide (at a molar ratio of at least 1.5 relative to the linseed oil) were mixed with stirring, and the entire amount of the reaction solution containing lipase was added in small portions and stirred at 25°C for at least 6 hours. After stirring, the mixture was subjected to solid-liquid separation using a 100-mesh filter, and the solid matter was collected. The separated liquid matter was treated as waste liquid.

[0054] The water content of the obtained solid was approximately 40% by mass. This solid was dehydrated in an evaporator under conditions of a vacuum of 10 to 20 Torr and a water bath temperature of 85°C, while maintaining a product temperature of 27 to 35°C, until the water content reached 25 to 28% by mass. Next, antioxidant caramel (6.5% by mass based on the solid weight of fatty acid calcium) preheated to approximately 40°C was added to the dehydrated solid, and the mixture was mixed and dried under reduced pressure. Specifically, the mixture was mixed and dried under conditions of a vacuum of 10 to 20 Torr and a water bath temperature of 85°C, while maintaining a product temperature of 27 to 35°C, until the water content reached 12 to 13.5% by mass, to obtain a feed composition. The obtained feed composition was brown granular (see Figure 3(a)).

[0055] The antioxidant caramel used in Example 1 was prepared by mixing 72.5 parts by mass of glucose, 4.5 parts by mass of sodium carbonate as a basic compound, and 23 parts by mass of water, reacting them at 130°C for 3 hours, and then adding 23 parts by mass of water to adjust the viscosity. The antioxidant activity of the antioxidant caramel was 1.064.

[0056] The weights of the water content, crude lipid content, and ash content of the obtained feed composition were measured by the following methods, and the mass percentages relative to the total amount of the feed composition were calculated. The results are shown in Table 1. <Moisture> 2 to 5 g of the feed composition was accurately weighed into a glass beaker (which had been dried and accurately weighed beforehand), and 15 g of sea sand was added to this and stirred well. The mixture was dried at 105±2°C for 3 hours, allowed to cool in a desiccator, and then accurately weighed. The weight of the water content was calculated from the difference in weight before and after drying. <crude lipid> Crude lipids were determined using the acid hydrolysis / diethyl ether extraction method. The acid value of the crude lipids was measured to determine the total amounts of free fatty acids (Ca-bound), triacylglycerols (TG), diacylglycerols (DG), and monoacylglycerols (MG). The content of Ca-unbound free fatty acids was determined by adding an ether-ethanol mixture (2:1) to the feed composition, shaking vigorously, filtering through filter paper, adding a few drops of phenolphthalein indicator to the filtrate, and titrating it with 0.1 N potassium hydroxide-ethanol solution. <ash content> 2 to 5 g of the feed composition was accurately weighed, placed in a crucible, and gently heated to carbonize, then heated at 550 to 600°C for 4 hours to incinerate, allowed to cool in a desiccator, and then accurately weighed to determine the weight of the ash.

[0057] <Fatty acid calcium production rate> The production rate of fatty acid calcium (Ca-bound free fatty acid) in the feed composition was calculated, assuming that the production rate when all of the constituent fatty acids in the linseed oil (deodorized oil) used as the raw material oil and fat were converted to fatty acid calcium was 100%.

[0058] Example 2 40 kg of linseed oil (deodorized oil) was added to a reaction vessel, and a lipase solution prepared by dispersing 345 U of Lipase OF (manufactured by Meito Sangyo Co., Ltd.) in 40 kg of water (equal to the weight of the linseed oil) per 1 g of linseed oil was added to the reaction vessel with stirring, and the mixture was stirred for 6 hours or more at 30° C. After that, the stirring and heating were stopped and the mixture was allowed to stand for 15 hours for separation, and 36.8 kg of the aqueous layer was discharged.

[0059] The oil layer remaining in the reaction vessel (a lipase-treated solution containing linseed oil fatty acids and water) was transferred to a reaction vessel for producing fatty acid calcium. Antioxidant caramel (5.25% by mass based on the solid weight of the fatty acid calcium to be produced), which had been preheated to 30°C, was then added. The product temperature was then raised to 95°C with stirring, and 5.48 kg of calcium hydroxide (at a molar ratio of 1.5 or more relative to linseed oil) was added. Air was sealed in the reaction vessel, and stirring was continued at approximately 100°C for 25 minutes while applying pressure. The reaction to produce fatty acid calcium in a semi-molten state was then carried out. After the reaction, the semi-molten fatty acid calcium was discharged from the bottom of the reaction vessel and collected on a tray. The collected fatty acid calcium solidified as the product temperature decreased, so it was left to stand at room temperature for 15 hours. The solidified fatty acid calcium was then crushed into blocks and pulverized using a food mixer to obtain a feed composition. The resulting feed composition was a brown-colored powder (see Figure 3(b)). For this feed composition, the weights of water, crude lipids, and ash were measured in the same manner as in Example 1.

[0060] Comparative Example 10.6 parts by mass of calcium hydroxide was added to 78 parts by mass of linseed oil (deodorized oil), and the mixture was mixed and stirred in a mixing tank. 4 parts by mass of antioxidant caramel prepared in the same manner as above, 7.4 parts by mass of water, and 0.04 parts by mass of Lipase PL (manufactured by Meito Sangyo Co., Ltd.) were added to this mixture, and the mixture was heated to 40°C and stirred for an additional 30 minutes. A block-shaped solid was removed from the mixing tank and placed in a container. The mixture was then left to stand at room temperature for 30 hours, and the solidified mixture was removed from the container and pulverized using a hammer mill. As a result, a yellowish powdery feed composition was obtained (see Figure 3(c)). Lipase PL is an alkali-resistant lipase. The weights of the moisture, crude lipids, and ash of this feed composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0061] [Table 1]

[0062] As shown in Table 1, the moisture values of the feed compositions of Examples 1 and 2 and the Comparative Example were approximately 10% by mass. The free fatty acids (Ca-bound) were higher in the feed compositions of Examples 1 and 2 than in the feed composition of the Comparative Example, demonstrating that a feed composition with a higher content of fatty acid calcium was obtained. Furthermore, the separately calculated fatty acid calcium production rate was 76.9% for the Comparative Example and 80.7% for Example 1, demonstrating superior results for Example 1. The production method of Example 1 differs from the Comparative Example (prior art) in that the enzymatic hydrolysis step and salt production step are carried out stepwise, allowing the use of a regio-nonselective lipase, which is thought to have improved hydrolysis efficiency. Furthermore, although the production method of Example 1 involves a solid-liquid separation step to separate solids, it does not require the work of removing the solidified material from the container as in the prior art, and therefore provides good workability even in mass production.

[0063] On the other hand, the fatty acid calcium production rate in Example 2 was 75.0%. However, the production method of Example 2 allows the fatty acid calcium production reaction to be carried out in a short time by the semi-melting method, and it is thought that the fatty acid calcium production rate can be further increased by extending the reaction time by an additional 5 to 10 minutes. Furthermore, in Example 2, the reaction can be completed within the reaction tank for fatty acid calcium production, so that after discharge, the product can be immediately crushed when solidified by cooling, thereby making it possible to shorten the working time compared to conventional techniques.

[0064] <Peroxide Value (POV)> The POV of the feed composition of Example 1 was measured immediately after production, and after filling it into an aluminum pouch and storing it in a warehouse (25°C) for 7 days. The measurements were performed in accordance with "Standard Test Methods for the Analysis of Fats, Oils, and Related Materials" compiled by the Japan Oil Chemists' Society. The POV was 0.27 immediately after production, and 0.49 after 7 days. Both the POVs immediately after production and after 7 days were 1 or less, indicating excellent oxidation stability. Meanwhile, the POV of Example 2 was measured in the same manner as in Example 1, and the POVs immediately after production and after 7 days were 0. [Industrial Applicability]

[0065] The method for producing a feed composition of the present invention comprises an enzymatic decomposition step and a salt production step, and can improve the production rate of fatty acid calcium and produce a feed composition containing a high content of fatty acid calcium, making it suitable for use in the livestock industry.

Claims

1. A method for producing a feed composition containing fatty acid calcium, comprising: The method comprises an enzymatic decomposition step of enzymatically decomposing a triglyceride containing unsaturated fatty acids as constituent fatty acids by mixing the triglyceride with lipase in the presence of water, a salt production step of adding calcium hydroxide to the decomposition product obtained in the enzymatic decomposition step and mixing the resulting product to produce fatty acid calcium salts, and a solidification step, The salt-forming step is a step of heating the fatty acid calcium salt at a temperature close to the melting point of the fatty acid calcium salt, The solidification step is a step of discharging the semi-molten processed product obtained after the salt production step, and cooling and solidifying the product.

2. 2. The method for producing a feed composition according to claim 1, wherein the enzymatic decomposition step is carried out at 30 to 50°C for 2 hours or more.

3. 3. The method for producing a feed composition according to claim 1, wherein the salt-forming step comprises stirring the fatty acid calcium salt at a temperature near the melting point of the fatty acid calcium salt for one hour or less.

4. 4. The method for producing a feed composition according to claim 1, wherein the triglyceride contains n-3 fatty acids in an amount of 50% by mass or more based on the total amount of constituent fatty acids.

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