JP7699794B2 - Method for producing a feed composition - Google Patents

Description

The present invention relates to a method for producing a feed composition containing fatty acid calcium.

Conventionally, feed compositions containing triglycerides and fatty acids have been widely used in feed given to livestock animals such as cows and pigs. These are formulated with the aim of efficiently supplying energy, and among them, fatty acid calcium, which is a metal salt of fatty acid, is mainly formulated for dairy cows to suppress the decrease in milk fat in summer. In addition, fatty acid calcium containing n-3 fatty acids using linseed oil and the like as raw oils and fats is formulated in feed with the aim of improving the quality by transferring n-3 fatty acids to meat (beef, pigs, chickens, etc.) and eggs. For example, fatty acid calcium is mixed into the feed in advance by a feed company, or added to each feed just before feeding at each livestock farm.

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

JP 2018-108076 A

In the above 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, and as a result, the production rate of fatty acid calcium varies. In the above Patent Document 1, the enzymatic hydrolysis is performed 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.

In addition, in the manufacturing method of Patent Document 1, raw materials containing triglyceride, calcium hydroxide, caramel with antioxidant properties, and lipase are mixed for about 30 minutes, and then transferred to a separate container when the viscosity increases, where the enzymatic decomposition reaction of fats and oils and the reaction to produce fatty acid calcium are carried out for about 30 hours to solidify. The solidified material is then removed from the container and crushed to obtain fatty acid calcium. However, it is believed that there is room for improvement in terms of workability with this method.

The present invention was made in consideration of these 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.

The method for producing a feed composition of the present invention is a method for producing a feed composition containing fatty acid calcium, and is characterized by having an enzymatic hydrolysis step in which a triglyceride containing an unsaturated fatty acid as a constituent fatty acid is mixed with lipase in the presence of water to enzymatically hydrolyze the triglyceride, and a salt production step in which the hydrolysis product obtained in the enzymatic hydrolysis step is mixed with calcium hydroxide to produce fatty acid calcium.

The lipase is characterized in that it is a position-nonspecific lipase for the triglyceride. The enzymatic hydrolysis process is also characterized in that it is carried out at 30°C to 50°C for 2 hours or more.

The above manufacturing method is further characterized by having a solid-liquid separation process for separating solid matter from the treated product after the salt production process, and an oxidation prevention process for mixing the separated solid matter with antioxidant caramel.

The solid-liquid separation process is characterized by having a dehydration treatment in which the separated solid matter is dehydrated so that its moisture content is 10% to 30% by mass.

The salt production process is characterized by heating the fatty acid calcium salt at a temperature near the melting point in the presence of antioxidant caramel.

The above manufacturing method is further characterized by having a solidification step for solidifying the treated material after the above salt production step, and a crushing step for crushing the solidified treated material.

The antioxidant caramel is characterized by a decrease in absorbance at 517 nm per mg of 0.6 to 1.1 after reacting with a 0.5 mM ethanol solution of 1,1-diphenyl-2-picrylhydrazyl (DPPH) at 37°C for 30 minutes.

The method for producing a feed composition of the present invention includes 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, making it possible to use 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.

The above 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 95-97%). Position-nonspecific lipases are generally cheaper than alkaline lipases, and can reduce costs. The enzymatic hydrolysis process is carried out at 30°C to 50°C for 2 hours or more, which promotes lipase activity and ensures enzymatic hydrolysis.

The manufacturing method of the present invention further includes a solid-liquid separation step for separating solids, and an oxidation prevention step for mixing the obtained solids with antioxidant caramel, so that there is no need to remove the solidified material from the container as in the conventional technology. In addition, in the conventional technology, after the reaction liquid is poured into another container, the reaction liquid remaining in the tank may also solidify, which may require time for cleaning the tank, but this cleaning is not necessary. As a result, the work efficiency is improved.

The solid-liquid separation process includes a dehydration treatment to dehydrate the separated solid matter so that its moisture content is 10% to 30% by mass, which makes it easier to carry out the subsequent oxidation prevention process appropriately. Specifically, foaming that accompanies the addition of antioxidant caramel during vacuum drying using a double cone or the like can be suppressed, and the antioxidant caramel contains 10% or more moisture, which makes it easier for the antioxidant caramel to blend with the fatty acid calcium particles, and the antioxidant caramel can be appropriately coated with the fatty acid calcium by being mixed uniformly.

The salt production process involves heating the fatty acid calcium salt at a temperature close to its melting point, reacting the fatty acid (including water) after enzymatic decomposition with calcium hydroxide to produce fatty acid calcium salt in a semi-molten state, so that the reaction to produce fatty acid calcium salt can be completed quickly (for example, within one hour). As a result, the work efficiency can be improved.

The antioxidant caramel has a certain antioxidant activity as evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), so it can effectively prevent the oxidation of unsaturated fatty acids even when using triglycerides with a high content of unsaturated fatty acids, such as linseed oil.

FIG. 1 is a flow chart showing an example of a method for producing a feed composition of the present invention. FIG. 2 is a flow chart showing another example of the method for producing a feed composition of the present invention. 1 shows photographs of the appearance of feed compositions of Examples and Comparative Examples.

The method for producing the feed composition of the present invention will be described with reference to Figure 1. Figure 1 is a flow diagram showing an example of the method for producing the 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 oxidation prevention step (S4). The feed composition obtained by this production method is used as feed for livestock animals. Each step will be described in detail below.

[Enzyme decomposition step (S1)]
This step is a step of enzymatically decomposing triglycerides using lipase. The triglycerides that are the raw oils and fats may have at least one constituent fatty acid that is an 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 and fats that contain these unsaturated fatty acids include linseed oil, soybean oil, rapeseed oil, corn oil, perilla oil, fish oil, and green nut oil, and these can be used alone or as a mixture.

The raw oils and fats preferably contain n-3 fatty acids such as α-linolenic acid, EPA, and DHA at a content of 50% by mass or more of the total constituent fatty acids, and more preferably contain α-linolenic acid at a content of 50% by mass or more of the total constituent fatty acids. Specific examples of such raw oils and fats include linseed oil and perilla oil.

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 is preferably 1 to 10, more preferably 2 to 6.

Linseed oil is a vegetable oil extracted from linseed, the seed of flax (Linum usitatissimum). After the oil is extracted from linseed, it is degummed, deacidified, bleached, etc. to remove moisture, gums, free fatty acids, color components, etc., and linseed oil is commercially available, and such commercially available products can be used as the raw oil. In addition, deodorized linseed oil can also be used as linseed oil.

The lipase used in step S1 is not particularly limited, and lipase derived from animals, plants, or microorganisms can be used. For example, lipases originating from the genera Candida, Aspergillus, Mucor, Pseudomonas, and Burkholderia can be used. Regarding the position specificity of triglycerides, lipases include 1,3-specific lipases and position non-specific lipases. Commercially available 1,3-specific lipases include, for example, Lipase AK "Amano" (manufactured by Amano Enzyme Co., Ltd., derived from Pseudomonas fluorescence), 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).

In the present invention, from the viewpoint of hydrolysis efficiency, it is preferable to use a position-nonspecific lipase, that is, 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 preferable as position-nonspecific lipases, and examples of commercially available products include 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).

The amount of lipase added in step S1 is appropriately set depending on the activity of the lipase, but for example, lipase with a titer of 100 U to 1000 U is added per 1 g of raw oil or fat, and preferably 300 U to 1000 U is added. 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 oil or fat while stirring.

The amount of water added in step S1 (including the water in the lipase solution) is, for example, 0.5 to 5 times the weight of the raw oil. Considering the efficiency of hydrolysis 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 oil.

The S1 step is preferably carried out at 30°C to 60°C. This temperature range provides excellent lipase reaction temperature, activity, and thermal stability, and is expected to be highly effective. More preferably, it is 30°C to 50°C, and even more preferably, it is 30°C to 45°C. The heating time for the S1 step is preferably 2 hours or more, and more preferably 4 hours or more, in order to complete the enzymatic decomposition. When using raw material 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 heating time has ended, the reaction may be continued for a predetermined period of time without heating, if necessary.

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

[Salt production step (S2)]
This step is a step of producing fatty acid calcium using calcium hydroxide. For example, the reaction liquid after step S1 is added to another reaction tank containing calcium hydroxide and water while stirring. Water may be used as necessary, and when used, the amount used is, for example, 2 to 10 times the weight of the raw oil and fat. After the entire reaction liquid after step S1 is added, it is stirred at room temperature (for example, 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 acid generated in step S1 reacts with calcium hydroxide, and fatty acid calcium particles are precipitated as a solid.

The molar ratio of calcium hydroxide used in step S2 is not particularly limited, but is preferably 1.2 to 2.0, and more preferably 1.3 to 1.8, relative to the raw oil. For example, when linseed oil is used as the raw oil, 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 the constituent fatty acids of the linseed oil and the weight of linseed oil used.

[Solid-liquid separation step (S3)]
This step is a step of separating solid matter from the treated product after step S2. As a means for solid-liquid separation, a well-known means for solid-liquid separation can be adopted, 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) as the filter. The separated liquid is treated as waste liquid after pH adjustment, etc.

The solid obtained by the solid-liquid separation means may be used as is in the subsequent step S4, but 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. In order to minimize foaming caused by vacuum drying in the subsequent oxidation prevention step, a lower moisture content is preferable, but the moisture content is set to, for example, 10% by mass or more in order to make the antioxidant caramel more compatible with the fatty acid calcium particles and to mix the caramel uniformly. The moisture content of the solid after dehydration is preferably 20% to 30% by mass.

From the viewpoint of preventing oxidation, it is preferable that the dehydration treatment is carried out under conditions where 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, etc. For example, when using a vacuum drying device such as an evaporator, the dehydration is carried out at a vacuum degree 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 conductive heat transfer type rotary dryer such as a double cone. Note that the above dehydration treatment may be carried out by combining multiple methods. For example, after centrifugation, drying using a double cone may be carried out.

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

In addition, if suction filtration or centrifugation is used instead of mesh filtration as a means of solid-liquid separation, the process can be continued while separating the solids until the moisture content of the solids becomes 30% by mass or less, as in the above numerical range.

[Antioxidation step (S4)]
In this step, the solid matter separated in step S3 and the antioxidant caramel are mixed and stirred to obtain a feed composition. The antioxidant caramel is a caramel having antioxidant properties, which is obtained, for example, by heating an aqueous solution of a monosaccharide of pentose or hexose under a specific condition in the presence of a basic compound. When adding the antioxidant caramel to the solid matter, it is preferable to heat the antioxidant caramel to about 40°C in advance and add it in a fluid state.

The amount of antioxidant caramel added is preferably 1% to 10% by weight, more preferably 4% to 10% by weight, 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 solid matter after the dehydrated S3 step 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 matter.

Examples of monosaccharides used as raw materials for antioxidant caramel include glucose, xylose, galactose, and fructose, and among these, glucose is preferred because it is easy to obtain and inexpensive. In addition, 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 hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate, sodium salts and ammonium salts of organic acids such as acetic acid and citric acid, and ammonium hydroxide. As the antioxidant caramel used in the present invention, it is preferable to use caramel obtained by heat-treating glucose and sodium carbonate.

Antioxidative 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.

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 specified amount of the above caramel is dissolved in ethanol, to which a 0.5 mM ethanol solution of DPPH is added, and the mixture is kept 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. From this regression line, the amount of absorbance reduction per mg of caramel is calculated, and this value can be used to evaluate the antioxidant properties of the caramel. This value is preferably 0.6 to 1.1.

In step S4, mixing of the solid matter and the antioxidant caramel and drying of the processed product may be performed simultaneously. For example, mixing and stirring can be performed under a specified degree of vacuum and a specified temperature condition. In this case, it is preferable to perform the process under conditions where the product temperature is maintained at 40°C or less, preferably 25°C to 35°C. The degree of vacuum is preferably 10 Torr to 50 Torr, and the heating temperature is preferably 50°C to 90°C.

In step S4, mixing and drying may be performed as separate processes rather than simultaneously. In this case, the solid matter and antioxidant caramel are mixed at room temperature (e.g., 25°C) without heating. The subsequent drying is performed under reduced pressure under conditions that maintain the product temperature at 40°C or less. For example, drying is performed at a reduced pressure of 10 Torr to 50 Torr and a heating temperature of 50°C to 90°C.

The drying in step S4 is carried out until the moisture content of the treated material reaches a predetermined moisture content (e.g., 13.5% by mass). If necessary, the feed composition obtained by drying may be pulverized into a powder form using a hammer mill or other pulverizing device.

In the manufacturing method of FIG. 1, a preferred embodiment for 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 oxidation prevention step (S4), antioxidant caramel is added and the solid is further dried until the moisture content is 10% to 13.5% by mass. In this case, the solid-liquid separation step includes a dehydration treatment, and the oxidation prevention step includes a drying step.

A specific example of the preferred embodiment is shown below. The fatty acid calcium produced in the salt production step (S2) is all put into the double cone while still containing water. This double cone is equipped with a mesh at the outlet, and solid-liquid separation and dehydration (drying) are performed by this double cone. 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 are dried to a moisture content of 10% to 30% by mass, antioxidant caramel is added through a nozzle while rotating the double cone without releasing the vacuum, and the caramel is mixed with the fatty acid calcium particles and dried until the moisture content is 10% to 13.5% by mass. By performing steps S3 and S4 in this sequence, it is possible to further improve the efficiency of the work.

Figure 2 is a flow diagram 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 described above, and therefore will not be explained here.

[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 liquid in step S1 is transferred to another reaction tank, and calcium hydroxide, water, and antioxidant caramel are added thereto while stirring. Water may be used as necessary, and the amount used when water is used is, for example, 0.001 to 1.0 times the weight of the raw material fat. In addition, 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 applied within the above-mentioned numerical ranges. After calcium hydroxide, water, and antioxidant caramel are added to the oil layer (containing water) of the reaction liquid after step S1, the mixture is stirred for 1 hour or less, preferably 10 to 30 minutes, at a temperature near the melting point of fatty acid calcium, for example.

Unlike step S2 in the manufacturing method of FIG. 1 described above, step S2' is carried out under a specified heating condition. 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 oil. For example, when linseed oil is used as the raw 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 while controlling the reaction temperature in the presence of a small amount of water, fatty acid calcium can be produced in a semi-molten state, and the reaction can be completed quickly.

[Solidification step (S5)]
The treated 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 decomposition reaction of fats and oils and the reaction for producing fatty acid calcium are carried out in separate containers, and are left to stand for a long time (about 30 hours). In contrast, in the manufacturing method of FIG. 2, the enzymatic decomposition reaction of fats and oils and the reaction for producing fatty acid calcium are completed in stages before step S5, and this step S5 is carried out to solidify the fatty acid calcium in a semi-molten state. In other words, the conventional technology and the manufacturing method of FIG. 2 have different purposes after transferring to a separate container. As a result, the standing time in step S5 can be made shorter than the standing time in the conventional technology (about 30 hours), and work efficiency can be improved.

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

In the manufacturing method of the present invention, in addition to the raw oil and fat, lipase, calcium hydroxide, water, and antioxidant caramel, other additives may be added as appropriate. For example, a palatability improver such as molasses, an emulsifier such as glycerin fatty acid ester, a fungicide such as propionic acid, a sweetener such as sodium saccharin, a flavoring, etc. may be added as appropriate.

The feed composition obtained by the above-mentioned manufacturing method can be fed to livestock animals as is, or can be mixed with other feed compositions and fed as 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.

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 1
600g of linseed oil (deodorized oil) was added to a reaction tank, and a lipase solution was added to the reaction tank, in which 345U of Lipase OF (manufactured by Meito Sangyo Co., Ltd.) was dispersed in 420g of water (0.7 times the weight of linseed oil) per 1g of linseed oil, while stirring, and the mixture was stirred at 40°C for 6 hours or more. 1634g of water and 81.58g of calcium hydroxide (molar ratio of 1.5 or more to linseed oil) were mixed and mixed in another reaction tank, and the above reaction solution containing lipase was added in small amounts in total, and the mixture was stirred and mixed at 25°C for 6 hours or more. After stirring, the mixture was separated into solid and liquid using a 100 mesh filter, and the solid matter was separated. The separated liquid matter was treated as waste liquid.

The water content of the obtained solid was about 40% by mass. This solid was dehydrated in an evaporator under conditions of a vacuum degree of 10 Torr to 20 Torr and a water bath temperature of 85°C, while maintaining the product temperature at 27°C 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 about 40°C was added to the dehydrated solid, and mixed and dried under reduced pressure. Specifically, the mixture was mixed and dried under conditions of a vacuum degree of 10 Torr to 20 Torr and a water bath temperature of 85°C, while maintaining the product temperature at 27°C 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)).

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 the mixture 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.

The weights of the moisture, crude lipids, and ash 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 in advance), 15 g of sea sand was added to this and mixed well, and the mixture was dried at 105±2°C for 3 hours. After cooling in a desiccator, the mixture was accurately weighed and the weight of the water content was calculated from the difference in weight before and after drying.
<crude lipid>
The crude lipid was determined using the acid decomposition diethyl ether extraction method. The total amount of free fatty acid (Ca-bound type) and triacylglycerol (TG), diacylglycerol (DG), and monoacylglycerol (MG) was determined by measuring the acid value of the crude lipid. The Ca-unbound free fatty acid content was determined by adding an ether-ethanol mixture (2:1) to the feed composition, shaking vigorously, filtering using filter paper, adding a few drops of phenolphthalein indicator to the filtrate, and titrating it with 0.1N potassium hydroxide-ethanol solution.
<Ash content>
2 to 5 g of the feed composition was accurately weighed out, placed in a crucible, and gently heated to carbonize, then heated at 550°C to 600°C for 4 hours to convert to ashed material, allowed to cool in a desiccator, and then accurately weighed to determine the weight of the ash.

<Fatty acid calcium production rate>
The production rate of fatty acid calcium (Ca-bound free fatty acid) in the feed composition was calculated based on the production rate of 100% 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.

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

The oil layer remaining in the reaction tank (a lipase-treated liquid containing linseed oil fatty acids and containing water) was transferred to a reaction tank for producing fatty acid calcium, and antioxidant caramel (5.25% by mass relative to the solid weight of the produced fatty acid calcium) preheated to 30°C was added thereto. Furthermore, the product temperature was raised to 95°C while stirring, and then 5.48 kg of calcium hydroxide (molar ratio of 1.5 or more relative to linseed oil) was added, and air was sealed in the reaction tank and stirring was continued for 25 minutes at about 100°C while applying pressure, and the reaction for producing fatty acid calcium was carried out in a semi-molten state. After the reaction, the fatty acid calcium in a semi-molten state was discharged from the bottom of the reaction tank 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 obtained feed composition was in the form of a brown powder (see Figure 3 (b)). The weights of moisture, crude lipids, and ash of this feed composition were measured in the same manner as in Example 1.

Comparative Example 10.6 parts by mass of calcium hydroxide was added to 78 parts by mass of linseed oil (deodorized oil), and mixed and stirred in a mixing tank. 4 parts by mass of antioxidant caramel produced 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, the liquid temperature was heated to 40°C, and the mixture was further stirred for 30 minutes, and a block-shaped solid was taken out of the mixing tank and placed in a container. After that, the mixture was left to stand at room temperature for 30 hours, and the solidified mixture was taken out of the container and crushed by a hammer mill crushing device. As a result, a yellowish powdery feed composition was obtained (see FIG. 3(c)). Note that Lipase PL is an alkali-resistant lipase. The weights of moisture, crude lipids, and ash were measured for this feed composition in the same manner as in Example 1. The results are shown in Table 1.

As shown in Table 1, the moisture content of the feed compositions of Examples 1-2 and Comparative Example was approximately 10% by mass. The free fatty acid (Ca-bound type) was higher in the feed compositions of Examples 1-2 than in the feed composition of Comparative Example, and it was found that a feed composition with a higher content of fatty acid calcium was obtained. In addition, the fatty acid calcium production rate calculated separately was 76.9% in the Comparative Example and 80.7% in Example 1, and Example 1 was a superior result. Here, the production method of Example 1 differs from the Comparative Example (conventional technology) in that the enzymatic decomposition step and the salt production step are carried out in stages, allowing the use of a position-nonselective lipase, which is thought to have increased the hydrolysis efficiency. In addition, although the production method of Example 1 includes a step of separating solids by a solid-liquid separation step, it does not require the work of removing the solidified solids from the container as in the conventional technology, and the workability is good even in mass production.

On the other hand, the fatty acid calcium production rate in Example 2 was 75.0%. However, the manufacturing method of Example 2 allows the fatty acid calcium production reaction to be carried out in a short time using the semi-melting method, and it is believed that the fatty acid calcium production rate can be further increased by extending the reaction time by an additional 5 to 10 minutes. Also, in Example 2, the reaction can be completed within the reaction tank for fatty acid calcium production, so that after discharge, the material can be immediately ground when it solidifies by cooling, making it possible to reduce the working time compared to conventional technology.

<Peroxide Value (POV)>
The POV of the feed composition of Example 1 immediately after production and after 7 days of storage in a warehouse (25°C) after filling an aluminum pouch bag were measured. The measurements were performed in accordance with "Standard Methods for Analysis of Fats, Oils and Related Materials" compiled by the Japan Oil Chemists' Association. As a result, the POV immediately after production was 0.27, and the POV after 7 days was 0.49. Both the POVs immediately after production and after 7 days were 1 or less, indicating that the composition has excellent oxidation stability. On the other hand, the POV of Example 2 was measured in the same manner as Example 1, and the POVs immediately after production and after 7 days were 0.

The method for producing a feed composition of the present invention includes 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 (4)

A method for producing a feed composition containing fatty acid calcium, comprising the steps of:
The method includes an enzymatic hydrolysis step of mixing a triglyceride containing an unsaturated fatty acid as a constituent fatty acid with lipase in the presence of water to enzymatically hydrolyze the triglyceride, and a salt production step of adding calcium hydroxide and antioxidant caramel to the hydrolysis product obtained in the enzymatic hydrolysis step and mixing them to produce fatty acid calcium salts,
the lipase is a position-non-specific lipase for the triglyceride;
A method for producing a feed composition, characterized in that the salt production step is a step of heating the fatty acid calcium salt in the presence of the antioxidant caramel at a temperature close to the melting point of the fatty acid calcium salt. The method for producing a feed composition according to claim 1, characterized in that the enzymatic decomposition process is carried out at 30°C to 50°C for 2 hours or more. The method for producing a feed composition according to claim 1 or 2, further comprising a solidification step for solidifying the treated product after the salt production step, and a grinding step for grinding the solidified treated product. The method for producing a feed composition according to any one of claims 1 to 3, characterized in that the antioxidant caramel exhibits a decrease in absorbance at 517 nm of 0.6 to 1.1 per mg after reacting the antioxidant caramel with a 0.5 mM ethanol solution of 1,1-diphenyl-2-picrylhydrazyl (DPPH) at 37°C for 30 minutes.

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