JPH0662876A - Method for processing lipid - Google Patents

Abstract

PURPOSE:To make it possible to produce a lipid having arbitrary fatty acid composition in high purity and efficiently produce lipids having high value added. CONSTITUTION:When a mixture consisting of a raw material oil and fat and a raw material fatty acid is made to react with, a lipase enzyme to carry out ester interchange reaction, the raw material fatty acid is continuously or intermittently added to the reaction system as the ester interchange reaction proceeds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a lipid by an enzyme, more specifically, a transesterification reaction in which a raw fat and oil is reacted with a raw fatty acid using a lipase, and an acyl group in the fat is exchanged with that of the raw fatty acid. The present invention relates to a lipid processing method using.

[0002]

2. Description of the Related Art Hydrogenation, fractionation, transesterification and the like have been conventionally known as basic means for lipid processing.
Regarding the transesterification reaction, a method using lipase, which is a lipolytic enzyme, has been actively studied and reported in recent years. This method makes it easy to introduce a specific fatty acid into a specific site of triglyceride, which was difficult by transesterification using a conventional alkali metal catalyst, by utilizing the action site specificity of lipase. It is one of the high-potential lipid processing technologies that has received attention in the industrial world.

The lipase which is a hydrolase undergoes a hydrolysis reaction mainly when a large amount of water is present in the reaction system, and decomposes a lipid which is a triglyceride into a fatty acid and a diglyceride, a monoglyceride or glycerin. On the other hand, many studies have recently revealed that the presence of a minimum amount of water is indispensable for maintaining the active three-dimensional structure of a protein enzyme. For example, Dordick, JS: Enzyme Microbiol. Technol., 1
1 , 194 (1989), Zaks, A. et al .: J. Biotechnol., 8, 259
(1988), Klivanov, AM: Chemtechnology, 16 , 354 (1
986). Therefore, in order to efficiently carry out a transesterification reaction, which has a high potential as a lipid processing technique, it is necessary to maintain the minimum amount of essential water necessary for maintaining the active conformation around the lipase enzyme. Achieves a very low water content in the entire reaction system,
It is very important to construct a so-called slightly water reaction system.

In order to industrially realize such a fine water reaction system, carriers such as celite, perlite, cellulose powder, kaolinite and activated carbon have already been added to the aqueous lipase solution, and the lipase is physically adsorbed on these carriers. After that, means for separating water from the aqueous solution and drying to adjust the water content in the carrier is disclosed. As a reactor for carrying out a transesterification reaction using such a carrier-immobilized lipase, a packed tank type column reactor is generally used because of the nature of these carriers being fine particles. For example, Japanese Patent Publication No. 57-27159, Japanese Patent Publication No. 63-22795, Japanese Patent Publication No. 63-22798, Japanese Patent Publication No. 3-44757,
JP-B-62-43678, JP-A-62-61591, JP-A
62-61582, Japanese Patent Publication No. 57-6480, Japanese Patent Publication No. 3143
See JP-A No. 8 and JP-A-57-198798.

However, when industrially carrying out the transesterification reaction process of the column reaction system using the lipase immobilized on a carrier such as Celite as described above,
It has the following problems. First, as many researchers in this field have pointed out, the prices of commercially available lipase enzymes are higher than those of other hydrolases such as amylase and protease, and they are added by transesterification reaction. In the current situation where the market price of value-added products, such as cocoa butter substitute fats, is not significantly high, there is the problem that the lipase enzyme cost in the production cost is inevitably high. , For example, Macrae, AR: Biochem. So
c. Transactions, 17 , 1146 (1989), Yamane, T .: J. A.
m. Oil Chem. Soc., 64 , 1657 (1987), Hashimoto S .: Bioscience and Bioindustry, 47 , 36 (1989),
See Tamase Mase et al .: Bioindustry, 7, 455 (1990). Therefore, development of an inexpensive method for supplying a lipase enzyme has been earnestly desired.

Second, in the transesterification reaction of the column reaction system, the flow of the reaction solution in the reactor becomes a plug flow, and the reaction rate increases in the flow direction. As described above, in the transesterification reaction, the water content of the reaction system is an important operating factor in view of the balance with the hydrolysis reaction which is a side reaction. However, in the column reaction system,
Since the reaction liquid becomes a plug flow flow, it is extremely difficult to control the water concentration in the column to a constant value due to the characteristics of the device.In any case, it is possible to avoid the water concentration distribution in the column. Absent. According to the results of studies conducted by the present inventors, the presence of such a water concentration distribution not only affects the hydrolysis reaction which is a side reaction, but is also remarkable in deactivating the lipase enzyme immobilized on the carrier. (Kyotani, et al . : J. Ferment. Bioeng., 71
286, (1991)), construction of a reaction system capable of controlling the water concentration of the reaction system to a constant value in the transesterification reaction, and development of a necessary and appropriate use form of the lipase enzyme (immobilization method) are desired. Was there.

[0007] In order to overcome these drawbacks, the present inventors have used, as a lipase enzyme, an ester exchange reaction system (hereinafter referred to as the immobilized microbial cell method) which utilizes intracellular lipase of the microbial cells immobilized on a microbial support material. Has already been proposed (JP-A-60-34189, JP-A-62-118883, JP-A-63-146782, JP-A-64-63385,
JP 2-49582 JP, JP 1-309689 JP, JP
1-59078). In such an immobilized cell method, an immobilized lipase enzyme preparation can be inexpensively prepared by adjusting the culture conditions (Japanese Patent Laid-Open Nos. 62-118883 and 63-1).
46782, JP2-49582, JP1-309689
Issue). Also, in the immobilized cell method, it is possible to use any of the plug flow type and complete mixed type reaction formats by utilizing its characteristics, and the reaction solution is placed in the reactor filled with the immobilized cell. We have already reported an industrially advantageous transesterification process in which a completely mixed process can be constructed by circulating at high speed, and the water concentration inside the cells (near the lipase enzyme) can be controlled arbitrarily (special features). JP-A-64-63385, JP-A-1-59078).

[0008]

However, the transesterification reaction further has one industrial problem derived from its own reaction characteristics. The essence of the transesterification reaction is the randomization (disordering) of the fatty acid distribution between the sites of action. Therefore, the larger the difference in the constituent fatty acids at the action site between the raw material triglyceride to be processed and the target triglyceride, the larger the amount of the introduced raw material fatty acid source required (the transesterification reaction is an equilibrium reaction).
That is, in a general industrial process, the higher the concentration of the target product, the higher the efficiency in the recovery step, which is desirable. However, in the transesterification reaction, if the reaction product is to be obtained in a high concentration, The amount of the raw material fatty acid that must be introduced into the product extremely increases, and in the end, it becomes necessary to separate the raw material fatty acid introduced in a large amount in the recovery step, which is not industrially remarkable. For example, when a 1,3-regiospecific lipase is allowed to act on a mixture of 2-unsaturated triglyceride and a saturated fatty acid such as stearic acid or palmitic acid to carry out a transesterification reaction to produce a cocoa butter substitute fat, In order to increase the concentration of the product cocoa butter substitute fat in the total glyceride, a large amount of saturated fatty acid must be introduced into the reaction system. However, as a practical matter, these saturated fatty acids have low solubility in a solvent such as hexane, and it is difficult to add them in large amounts to the reaction system. Further, in order to introduce a large amount of saturated fatty acid into the reaction system, a large amount of solvent is required, and as a result, the volumetric efficiency of the reactor is reduced, and it is necessary to recover a large amount of solvent. Occurs.

In order to avoid such problems, many attempts have been made to carry out a transesterification reaction in a solvent-free system, but at present, a lipase having sufficient heat resistance has not been obtained, and the whole reactor has not been obtained. There are many industrial disadvantages such as requiring a large amount of energy to maintain the temperature at high temperature. Further, according to the results of studies by the present inventors, when the transesterification reaction is carried out at a high temperature, the rate of acyl group transfer in the glyceride molecule is accelerated, the yield of the product is lowered, and the quality of the product is adversely affected. However, it was found to be unfavorable industrially because of many new problems. Therefore, in the industrial transesterification reaction, the development of a method for increasing the concentration of the target product triglyceride without lowering the volumetric efficiency of the reactor has been an important subject for study in order to increase the productivity.

[0010]

Means for Solving the Problems As a result of intensive studies from the above viewpoints, the present inventors have conducted a transesterification reaction by causing a lipase enzyme to act on a mixture of raw fats and oils and fatty acids, By continuously or intermittently adding the raw material fatty acid to the reaction system along with the progress of the transesterification reaction, it was found that the concentration of the target triglyceride in the total triglyceride can be increased without lowering the volumetric efficiency of the reactor, The present invention has been completed. The method of carrying out the transesterification reaction while adding such a fatty acid to improve the productivity of the target triglyceride is carried out in a completely mixed transesterification reaction process using immobilized cells proposed by the present inventors. It is extremely effective.

In the transesterification reaction, since the raw material fatty acid is incorporated into the raw material fat and oil, the fatty acid composition and the fat and oil composition of the reaction system change with the progress of the reaction. According to the present invention, with such changes in the oil and fat composition and the fatty acid composition of the reaction system, the solubility of the raw material fatty acid that could not be introduced into the reaction system increases due to its low solubility at the start of the transesterification reaction. By utilizing this phenomenon, the raw material fatty acid is introduced into the reaction system at a concentration higher than the solubility at the start of the transesterification reaction to achieve a high concentration of the target product, oil or fat.

In the present invention, any saturated or unsaturated fatty acid having 2 to 30 carbon atoms existing in nature can be used as a raw material fatty acid, but the effect of the present invention is remarkably found. This is the case where 30 saturated fatty acids were used as raw material fatty acids. Specific examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid and melicinic acid.

In the present invention, as the raw material fats and oils, usual animal and vegetable fats and oils or synthetic fats and oils are used. Specifically, olive oil, palm oil, shea butter, soybean oil, cottonseed oil,
Safflower oil, sunflower oil, high oleic sunflower oil, high oleic safflower oil, camellia oil, mountain tea flower oil, tea oil, beef tallow, lard, fish oil, monkey fat, illipe fat,
Examples thereof include mango butter, coke butter, mauer butter, fluwara butter, triolein, tripalmitin, tristearin, diolein, dipalmitin, distearin, monoolein, monopalmitin, monostearin and the like. Further, the high melting point portion, the medium melting point portion and the low melting point portion of these oils and fats obtained after these oils and fats have been subjected to a normal fractional crystallization step can also be used as the starting oils and fats.

In the present invention, the above-mentioned raw material fats and oils and raw material fatty acids are diluted with an organic solvent such as n-hexane, isooctane, acetone, ethanol, methanol, petroleum ether, ethyl acetate and subjected to a transesterification reaction. It

In the present invention, when the raw material fatty acid is added to the reaction system along with the progress of the transesterification reaction, either a continuous method or an intermittent method can be applied. When the raw material fatty acid is solid or powder at room temperature,
In the case of intermittent supply, it can be added as it is, but in the case of continuous supply, it is convenient for operation to add it in a liquid state by heating it to a temperature above its melting point or dissolving it in the above organic solvent. is there. However, the method of adding by dissolving in this organic solvent causes a decrease in the volumetric efficiency of the reactor, so industrially, intermittently in a powder state,
Alternatively, it is preferable that the liquid be heated to a temperature equal to or higher than the melting point to be in a liquid state and supplied intermittently or continuously.

In the method of the present invention, the use form of the lipase which is a reaction catalyst when carrying out the transesterification reaction is as follows:
The material is not particularly limited as long as it can realize the slightly water environment required for the transesterification reaction. For example, lipase enzyme directly in powder form, or by a known method, Celite, activated alumina, activated clay, diatomaceous earth, activated carbon,
Immobilized lipase physically adsorbed and immobilized on a carrier such as perlite, cellulose powder, kaolinite, urethane prepolymer, carrageenan, alginic acid gel, entrapped and immobilized on photocurable resin, or cross-linking agent such as glutaraldehyde And a cross-linked and immobilized lipase is used. Furthermore, a dry microbial cell containing the lipase previously proposed by the present inventors can also be used. In the case of dried bacterial cells, the dried bacterial cells are directly cultured or, as previously reported, cultured with a microorganism retaining material,
It is also possible to immobilize it on the holding material at the same time as culturing, and then use the dried microorganism holding material-immobilized dry cells.

In the method of the present invention, since the raw material fatty acid is continuously or intermittently added as the transesterification reaction progresses, it is preferable that the inside of the reactor to be applied be in a completely mixed flow. When using the adsorption-immobilized lipase, entrapment-immobilized lipase, and cross-linking immobilized lipase, a plug flow flow column reactor is generally used, but even if these immobilized lipases are used, for example, in a stirring tank. Alternatively, the method of the present invention can be applied if the transesterification reaction is carried out by making the column multistage and stirring each stage. Under vigorous stirring conditions, destruction of the immobilized carrier occurs, and recovery and use of expensive lipase enzyme are expected to cause inconveniences such as difficulty in repeated use. Immobilized lipase physically adsorbed and immobilized on a carrier such as activated clay, diatomaceous earth, activated carbon, perlite, cellulose powder, kaolinite, urethane prepolymer, carrageenan, alginate gel, entrapped and immobilized on photocurable resin. It is necessary to pay attention to the reaction operation conditions when using a substance or a substance in which a cross-linking agent such as glutaraldehyde is used and a lipase is cross-linked and immobilized under a completely mixed flow condition.

On the other hand, in the method using the intracellular lipase proposed by the present inventors, particularly the method using the microorganism-supporting material-immobilized cells, the reaction liquid is rapidly fed into the reactor filled with the immobilized cells. By circulating or by setting the circulating liquid amount to an appropriate amount, the immobilized microorganisms can be made to flow, so that a complete mixed flow can be easily realized without introducing special equipment such as a stirrer. It is very convenient to apply the method. Furthermore, in the case of the microorganisms on which the microorganism-retaining material is immobilized, the intracellular lipase activity is remarkably amplified by the immobilization procedure as previously reported (JP-A-63-14678).
2), that the activity amplified by fed-batch culture is further amplified (JP-A-62-18883, JP-A-2-49582), and the transesterification reaction in the reaction system. It is easy to control the water concentration in the reaction solution, which is the most important operating factor in JP-A-64-63385, JP-A-1-309689, and JP-A-1-59078.
In such a situation that the lipase enzyme is expensive, it is possible to construct an industrially and economically advantageous transesterification reaction system, which is extremely convenient.

The target product (triglyceride), which has been increased to a high concentration by the method of the present invention, is subjected to a conventional method to recover the solvent by evaporation, and is subjected to transesterification from the remaining raw material fatty acid and raw material fat by vacuum distillation, for example steam distillation. After separating the fatty acid liberated as a result of the reaction, it is recovered as a product through a solvent fractionation crystallization step. The fatty acid mixture thus obtained (fatty acids liberated as a result of the transesterification reaction from the remaining raw material fatty acids and raw material fats or oils) or the remaining fats and oils obtained by recovering the target product as a product are again used as raw materials in the method of the present invention. Fats and oils,
It is industrially preferable to use it as a raw material fatty acid. In particular, in the method of the present invention, the amount of saturated fatty acid contained in the reaction solution is larger than that in the conventional method, so it is industrially necessary to recover and reuse the saturated fatty acid. Therefore, in the method of the present invention, the fatty acid mixture obtained by the above-mentioned distillation (fatty acid that has been liberated as a result of the transesterification reaction from the residual raw material fatty acid and raw material fat) is liberated from the raw material fat as a result of the transesterification reaction. It is preferable to remove the unsaturated fatty acid from the fatty acid and reuse it in order to increase the yield of the target product. Known methods for separating unsaturated fatty acids from such a mixture of saturated fatty acids and unsaturated fatty acids include, for example, solvent fractionation, solvent-free fractionation, molecular distillation, zone melting, urea addition method, adsorption separation and the like. Available.

On the other hand, the unsaturated fatty acid is not separated,
It is also possible to convert unsaturated fatty acids into saturated fatty acids and reuse them by a known hydrogenation method. This hydrogenation method is carried out, for example, by adding an appropriate catalyst to the fatty acid mixture and passing hydrogen gas while heating and stirring. At this time, if the temperature, pressure, type of catalyst, amount of hydrogen, etc. are properly selected, the hydrogenation reaction will occur rapidly, and if it is allowed to proceed as it is, all the unsaturated fatty acid double bonds will be saturated and the hydrogenation reaction will be completely completed. Hydrogen is added. In such a case, the saturated fatty acid obtained by hydrogenation can be reused as a raw material fatty acid for the transesterification reaction of the present invention. However, in the method of the present invention, the majority of the fatty acid mixture fed to the hydrogenation process is saturated fatty acids, and despite the low content of unsaturated fatty acids that must be hydrogenated, they are simultaneously hydrogenated. Since it has to be used for the reaction, the capacity of the reactor becomes unnecessarily large, which is not industrially preferable. Rather, the above-mentioned known methods, for example, solvent fractionation, solvent-free fractionation, molecular distillation, zone melting, urea addition, adsorption separation, etc., first separate saturated fatty acids and unsaturated fatty acids, then only unsaturated fatty acids. It is industrially more efficient to add hydrogen.

According to the experience of the present inventors, in the hydrogenation reaction, the reaction rate decreases as the unsaturated fatty acid content decreases, so that the processing time becomes enormous and industrially completely saturated. It is difficult to hydrocure even fatty acids. When the fatty acid mixture obtained when the hydrogenation is not completely completed is reused as the raw material fatty acid for the transesterification reaction not only in the method of the present invention, not only the yield of the target product is lowered but also the target product is obtained. It also causes problems such as deterioration of the quality of. The causative substance causing such a problem is an isomerized unsaturated fatty acid produced when hydrogenating an unsaturated fatty acid. For example, geometric isomers of elaidic acid and oleic acid produced when hydrogenating oleic acid are used. For example, a positional isomer in which the double bond at the center is moved to another position. According to the results of studies conducted by the present inventors, for example, when a cocoa butter substitute fat is produced by a transesterification reaction, when a fatty acid mixture containing these isomerized unsaturated fatty acids is used as a raw material fatty acid, isomerized unsaturated Fatty acids are incorporated into the cocoa butter substitute fat, which is the target product, and sharp melting properties are impaired, which reduces the product value of the cocoa butter substitute fat. According to the experience of the present inventors, such a phenomenon occurs when only a few percent of the isomerized fatty acid is present in the raw material fatty acid, and industrially, the unsaturated fatty acid is converted into a saturated fatty acid by the hydrogenation method. When it is converted and reused as a raw material fatty acid in the method of the present invention, the reaction conditions must be taken into consideration so that the isomerization reaction does not occur. Among the above methods, a method capable of suppressing the isomerization reaction, for example, solvent fractionation,
Solvent-free fractionation, zone melting, urea addition method, adsorption separation and the like are industrially preferable.

[0022]

EXAMPLES Next, the present invention will be explained using examples.
Of course, the present invention is not limited to these examples.

In the following examples, the bacterial cells immobilized on the microbial support were separated from the culture solution and then washed with tap water.
Wash twice, then twice with acetone, then at room temperature for 4
It was vacuum dried for 8 hours to prepare immobilized dry cells.

Further, since a general method for measuring the transesterification activity of lipase has not been established yet, in the present invention, olive oil: methyl stearate: hexane = 1: 4: 2.5 (weight ratio) Using a mixture of the following, an appropriate amount of lipase enzyme agent was added, and the mixture was reacted at 40 ° C. for a certain period of time, and the amount of the enzyme that produced 1 μmol of methyl oleate per minute was 1% from the amount of methyl oleate produced
A unit (1U) was used.

The compositions of methyl oleate and triglyceride were analyzed by gas chromatography and high performance liquid chromatography, respectively, according to known methods.

The amount of water contained in the immobilized enzyme or dried cells was measured by the known Karl Fischer method.

Example 1 1 part of a commercially available lipase of Rhizopus delemar (Seikagaku Kogyo Co., Ltd.) and 2 parts of diatomaceous earth were mixed, and then cold water was sprayed with stirring to form granules. It was vacuum dried at room temperature to obtain a diatomaceous earth-immobilized lipase having a water content of 2.3%. The same operation is performed on the commercially available Rhizop
us niveus lipase (Amano Pharmaceutical Co., Ltd.) and Celite,
Rhizopus japonicus lipase (Osaka Institute (made))
And perlite, Aspergillus nigar lipase (Amano Pharmaceutical Co., Ltd.) and kaolinite, respectively, with a celite-immobilized lipase having a water content of 3.3%, a perlite-immobilized lipase having a water content of 2.8%, and a water content of 4.1. % Kaolinite immobilized lipase was obtained. The transesterification activities of these immobilized lipase enzymes are shown in Table 1.

[0028]

[Table 1]

500 mg of these immobilized lipases and olive oil: palmitic acid: hexane = 1: 4: 10
15 g of the reaction mixture consisting of (weight ratio) was added to a 50 ml container and stirred with a magnetic stirrer while stirring 40 times.
The transesterification reaction was carried out at 24 ° C. for 24 hours. After starting the reaction
At 6 hours, 12 hours, and 18 hours, 0.25 g of palmitic acid was added in powder form and dissolved, and the transesterification reaction was continued. Table 2 shows the numbers of additions of palmitic acid for each immobilized lipase, 0 times, 1 time, 2 times, 3 times, respectively.
The amount of 1,3-dipalmitoyl-2-oleoylglycerol (POP), which is a reaction product in the triglyceride after 24 hours when the number of times is indicated, is shown.

[0030]

[Table 2]

Palmitic acid is hardly soluble in hexane, and it is difficult to dissolve olive oil: palmitic acid: hexane = 1: 4: 10 (weight ratio) or more in the reaction solution composition at the start of the reaction, but during the reaction It was possible to increase the total amount by sequentially adding to, and to make the target product a higher concentration.

Example 2 Rhizopus chinensis was prepared in the same manner as in Example 1 of JP-A-63-146782.
IFO 4768 was immobilized on a block-shaped polyurethane microbial support material (Bridgestone (product name), Everlite Scott HR-40) having a side length of 6 mm to prepare immobilized dry cells (transesterification activity: 15 U / g-). Carrier). The immobilized dried bacterial cells and commercially available immobilized lipase (Novo Co., Ltd., trade name: lipozyme; transesterification activity: 20)
U / g-carrier) was used to carry out the transesterification reaction between triolein (Wako Pure Chemical Industries, Ltd.) and behenic acid.
Immobilized dry cells and lipozyme (300 mg) in triolein: behenic acid: hexane = 1: 2: 20 (weight ratio)
15 g of the reaction solution having the composition of was added and reacted at 40 ° C. in the same manner as in Example 1 of the present application. On the way, 0.15 g of behenic acid was added at 6 hours, 12 hours, and 18 hours. The results are shown in Table 3.

[0033]

[Table 3]

It can be seen from Table 3 that the method of the present invention is effective for increasing the concentration of the target product without reducing the volumetric efficiency of the reaction solution even for behenic acid having extremely low solubility in hexane. I understand. In this reaction system, it was extremely difficult to dissolve behenic acid at a reaction liquid composition at the start of the reaction of at least triolein: behenic acid: hexane = 1: 2: 20 (weight ratio).

Example 3 Lipase-producing bacterium Rhizopus niv
Using the bubble column (Circulating bed fermentor) shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2-49582, eus IFO 4759
Immobilized cells were prepared by culturing with a block-shaped cellulosic microorganism-holding material having a side of 10 mm (Sakai Enex Co., Ltd., trade name: SIC-CS). However, as a vent for the bubble column, a sintered metal plate (manufactured by Nippon Seisen Co., Ltd., trade name: instead of the perforated plate shown in FIG. 2 of JP-A-2-49582) is used.
Naslon Filter Media Finepore NF-06) was used. The culturing method is described in Example 2 of JP-A-2-49582.
The specific substrate (meat extract) feed rate is 0.06 (g-) based on the empirical formula for predicting the bacterial cell concentration shown in Reference Example 1 of JP-A-2-49582. Meat extract) (g-cell) ^-1 (h) ^-1 was controlled and cultured.
The dried bacterial cells on which the cellulose microorganism-supporting material was thus obtained had a transesterification activity of 19 U / g-carrier. This cellulose-immobilized microbial cell was prepared as described in JP-A-1-309689.
Filled in the transesterification reactor shown in FIG. 5 of Japanese Patent Publication No. Heiolaik Sunflower Oil: Stearic Acid:
A reaction liquid having a composition of hexane = 1: 3: 12 (weight ratio) was charged to produce a cocoa butter substitute fat. The water concentration in the reaction solution is described in JP-A-64-63385,
It was controlled to 100 ppm throughout the reaction by the method disclosed in JP-A 1-309689. In RUN-1, stearic acid was not added in the middle and the batch reaction was performed for 18 hours.
In RUN-2, under the same reaction conditions as in RUN-1, stearic acid equivalent to 30% of stearic acid contained in the initial reaction liquid was continuously melted at a constant flow rate from the 3rd to 15th hours after the reaction was started. Was added to the reaction system, and batch reaction was performed for 18 hours. Table 4 shows the cocoa butter substitute fat (SOS: SOS: which is the target product at each reaction time of RUN-1 and RUN-2).
The changes in the concentration of 1,3-distearoyl-2-oleoylglycerol) were compared.

[0036]

[Table 4]

In the transesterification reaction bioreactor as used in this example, the raw material fatty acid is continuously added in the molten state as the reaction progresses, so that the bioreactor of the bioreactor can be obtained without complicated operations. We were able to increase productivity by 10% with volume efficiency unchanged.

(Example 4) RUN- in Example 3
From each reaction mixture after the reaction of 1 and RUN-2, hexane as a solvent was evaporated and collected according to a conventional method. Further, the fatty acid and the lipid triglyceride were separated by a conventional vacuum distillation. The separated triglyceride was further separated into a high melting point portion, a medium melting point portion and a low melting point portion by a conventional fractional crystallization, and the product cocoa butter substitute fat was recovered in the medium melting point portion. The yield (yield) in this fractional crystallization was 10% or more in RUN-2 in which the concentration of the cocoa butter substitute fat was increased.
In addition, the method of the present invention not only increased the productivity in the transesterification reaction step, but also had an effect on the recovery rate in the post-treatment step such as crystallization.

Next, the above-mentioned recovered fatty acid was subjected to the following two kinds of treatments to remove the unsaturated fatty acid liberated from the raw material fat as a result of the transesterification reaction. Using the same bioreactor as in Example 3, the fatty acid that had been subjected to these treatments was again used as a raw material fatty acid, and the low melting point portion obtained by the fractional crystallization of triglyceride was used as a raw material oil and fat again.
The transesterification reaction for producing cocoa butter substitute fat was carried out by the same procedure.

(Process 1) The recovered fatty acid was dissolved in hexane again, and three-stage crystallization was performed at crystallization temperatures of 40 ° C., 30 ° C. and 25 ° C. to recover a saturated fatty acid containing stearic acid.
The cake was washed several times with hexane during filtration to remove the unsaturated fatty acids entrained in the precipitated cake.

(Processing 2) A stirring tank (actual capacity: 10 L) type hydrogenation apparatus using a nickel metal catalyst at a temperature of 160 to 1
Add hydrogen to maintain a pressure of 3 kg / cm ² at 80 ° C,
The hydrogenation reaction was carried out for 1 hour.

The composition of the initial reaction solution was set to the mid-melting point: recovered fatty acid:
With hexane = 1: 2: 8 (weight ratio), the fatty acid treated in the same manner as in Example 3 was treated with the fatty acid, and the results with and without addition were shown in Table 5 and Treatment 2. The results with and without addition of fatty acid are shown in Table 6 as the reaction progressed.

[0043]

[Table 5]

[0044]

[Table 6]

The cocoa butter substitute fat obtained in Example 3,
When the quality of the cocoa butter substitute fat obtained by using the fatty acids subjected to the treatments 1 and 2 of Example 4 was compared, it was found that the treatment 1 of Examples 3 and 4 was a conventional product (fractionated from shea butter). It was not inferior to that of the crystallized product), but rather showed sharper meltability than the conventional product and was good. On the other hand, the treatment 2 of Example 4 exhibited unfavorable behavior such as a decrease in melt sharpness.

[0046]

INDUSTRIAL APPLICABILITY According to the method of the present invention, in the transesterification reaction using a saturated fatty acid having a low solubility in an organic solvent such as hexane as a raw material fatty acid in the production of cocoa butter substitute fat, the volumetric efficiency of the reactor is increased. It is possible to increase the concentration of the target product and improve its productivity without decreasing Further, such a high concentration of the target product leads to an improvement in the yield (yield) in the subsequent treatment step, which is extremely convenient industrially.

Claims (3)

[Claims] 1. When a lipase enzyme is allowed to act on a mixture of raw fats and oils and raw fatty acids to carry out transesterification, the raw fatty acids are added to the reaction system continuously or intermittently along with the progress of the transesterification reaction. Characteristic lipid processing method. 2. The method for processing a lipid according to claim 1, wherein the raw material fatty acid is a saturated fatty acid having a carbon number of 12 to 30. 3. A saturated fatty acid obtained as a raw material fatty acid by separating a fat and a fatty acid which are triglycerides from a transesterified reaction mixture and a fatty acid, and further removing an unsaturated fatty acid released from the raw material fat and oil by a transesterification reaction from the fatty acid. The lipid processing method according to claim 1 or 2, which is reused.