JPS6344892A - Ester exchange reaction of fats and oils - Google Patents

Abstract

PURPOSE:To make it possible to carry out only ester exchange efficiency and economically, by using a lipase agent having thermostability at >= enough temperature to fuse a reaction substrate but not a solvent and removing water from the reaction system in the reaction. CONSTITUTION:In carrying out ester exchange reaction of fats and oils by using an enzyme preparation containing lipase, 5-100pts.wt. based on 100pts.wt. fats and adds of an enzyme preparation (e.g. immobilized enzyme) containing a lipase (lipase produced from a thermostable strain of Rhizopus, Pseudomonus, Mucor, etc.) having thermostability at >= enough temperature to fuse a reaction substrate is used, but no solvent is used and water is removed from the reaction system. Consequently, hydrolysis of fats and oils are suppressed and only ester exchange can be efficiently and economically effected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for transesterification of oils and fats using lipase (lipid degrading enzyme). More specifically, the present invention relates to a method for transesterification of fats and oils using an enzyme preparation containing a lipase that has sufficient heat resistance at temperatures necessary to melt fats and oils and fatty acids as substrates.

Transesterification of oils and fats is an important processing technology along with hydrogenation in the production of edible processed oils and fats such as margarine and shortening. - [Prior Art] Transesterification of oils and fats has conventionally been carried out by chemical methods. That is, it has been carried out by a method using an alkaline substance such as an alkali metal, an alkali metal alcoholade, an alkali metal hydroxide, or various metal salts as a catalyst.

However, in this method, rearrangement of fatty acids in fats and oils occurs according to the law of indiscriminate distribution, so no specificity is observed in the positions of fatty acids that bind to the fats and oils obtained.

That is: - Conventional chemical methods are non-selective regarding the position of bound fatty acids in glycerides. This property may have the effect of improving the physical properties of fats and oils when the purpose is to produce edible processed fats and oils such as ordinary margarine and shortening. However, they have a unique glyceride composition. When the purpose is to produce fats and oils, this cannot be achieved using conventional non-selective methods.The unique glyceride composition referred to here means that most of the glycerides are symmetrical, such as in natural cocoa butter. This is a case where it has a structure.

Recently, when it is intended to produce such fats and oils, a method for regioselectively transesterifying fats and oils has been developed in place of the conventional non-selective chemical method.

That is, it is an attempt to regioselectively transesterify fats and oils using lipase, which is an enzyme that originally hydrolyzes fats and oils (Japanese Patent Application Laid-Open No. 104506/1983).
. According to this method, the presence of water in the reaction system is an essential condition for activating lipase. Although this water content is small at 0.2 to 1.0%, due to the inherent properties of lipase, hydrolysis of fats and oils will inevitably occur, and a decrease in the yield of exchange fat due to the by-product of diglyceride can be avoided. I can't. □Furthermore, in order to reduce by-products, it has been proposed to conduct the reaction by lowering the water content to 0.1% or less, but reducing the water content will substantially reduce the reaction rate, making it impractical. The above is not a good idea (
JP-A-55-71797).

Furthermore, as a method to increase the rate of transesterification, there have been proposals for a method in which the reaction process is divided into two stages, decomposition and synthesis (Japanese Patent Application Laid-Open No. 60-19495, Japanese Patent Application Laid-open No. 60-20).
3196), there are difficulties in controlling the reaction, especially in controlling the decomposition process. Although this method is interesting in that it focuses on diglycerides, it is technically difficult to selectively obtain only diglycerides in the decomposition process, and monoglycerides, monoglycerides,
At the same time as decomposition to glycerin occurs, more triglycerides remain undegraded. Furthermore, the presence of 1,3-diglyceride produced by non-enzymatic transfer of diglyceride inevitably reduces the yield of the desired transesterified product in the second stage synthesis step, and this adverse effect becomes particularly pronounced as the temperature increases. big. Furthermore, the second stage synthesis reaction rate cannot be said to be sufficient compared to the usual transesterification rate. From this perspective, it is judged that complication of process operations is unavoidable.

In addition, conventional enzyme preparations have insufficient heat resistance, and in particular when reacting a reaction substrate with a high melting point, it is necessary to use a solvent to dissolve the substrate. As a means to solve these problems, the development of heat-resistant enzyme preparations has recently been progressing (Japanese Patent Application Laid-Open No. 60-98984).
If the reaction is carried out without a solvent at a relatively high temperature for an enzyme reaction of 50°C or higher, the water contained in the enzyme preparation is likely to be released into the reaction system, resulting in an increase in the by-product of diglyceride and a decrease in yield. It had

As mentioned above, while the transesterification reaction of oils and fats using lipase has unique and advantageous points compared to the chemical methods mentioned above, there are still many problems that need to be solved.
These problems need to be solved for industrial implementation.

[Problems to be solved by the invention] ``From an industrial economic perspective, the use of solvents causes a decrease in productivity and a large loss of energy, so it is possible to carry out the reaction without using a solvent by using a heat-resistant lipase preparation. It is hoped that

On the other hand, the cost of the enzymes required to catalyze these reactions is still very high, and industrialization of these reactions requires reducing the amount of enzymes used or recovering and repeatedly using them. Become.

Attempts to reduce the amount of water in enzyme preparations actually lead to a reduction in the reaction rate, making the reaction equipment larger and reducing production efficiency.
Deterioration of enzymes over time cannot be avoided, and there is a natural limit to the amount of transesterified product that can be produced from a given weight of enzyme. As described above, no conventional technology has yet been found that achieves both the reaction rate and suppression of diglycerides from an industrial perspective, and the durability of enzymes from an economic perspective.

[Means for solving problems]

Under these circumstances, the present inventors have diligently studied methods for suppressing the hydrolysis of fats and oils and performing only transesterification efficiently and economically, and in order to solve the above five problems, the present inventors have developed a method for suppressing the hydrolysis of oils and fats and for the purpose of solving the above five problems. As a result of various studies on the transesterification method using an enzyme preparation (hereinafter abbreviated as a lipase agent) and the characteristics of lipase, an effective method for using a lipase agent was discovered and the present invention was completed.

That is, the present invention is a method for transesterifying oils and fats using a lipase agent, which uses a lipase agent that has heat resistance above a temperature sufficient to melt the reaction substrate, and without using a solvent. The present invention relates to a transesterification reaction method for oils and fats, which is characterized in that water is removed from the reaction system during the reaction.

In the present invention, the transesterification reaction of oils and fats refers to the transesterification reaction between fats and oils and fatty acids or fatty acid esters, the transesterification reaction between fats and oils, the transesterification reaction between fatty acid esters and fatty acids, and the transesterification reaction between fatty acid esters. It includes.

Pioneering research by Iwai, Tsujisaka et al. has revealed that lipase catalyzes not only hydrolysis but also the reverse synthesis reaction (M, Iwai).

Y, Tsujisaka, J, Fukumoto+
J, Gen, Appl, Microbiol.

10, 13. (1964)).

Based on this experimental fact, the present inventors analyzed the transesterification reaction of oils and fats from the perspective of enzyme chemistry and reaction engineering, and found that a complex of diglyceride and enzyme is involved in the reaction, and the transesterification rate is was found to be expressed by the following formula.

V=k [E-DG] [FA] where k is the overall reaction rate constant, [FA] is the fatty acid concentration,
[E-DG] represents the diglyceride/enzyme complex concentration.

Although k largely depends on the water content and enzyme concentration in the reaction system, increasing the water content only promotes an increase in free diglyceride, and no substantial increase in the transesterification rate is observed.

On the other hand, an increase in enzyme concentration suppresses the increase in free diglyceride in the reaction system, and from the above rate equation, 9
/”%M Obviously, it makes it possible to increase the rate of transesterification reaction. However, simply increasing the amount of lipase agent results in the water contained in the agent being easily released into the reaction system, which leads to an increase in the rate of the transesterification reaction. Suppression is difficult.

The present inventors focused on the fact that the synthetic ability of lipase varies depending on the moisture content, and that transesterification can be carried out efficiently without decomposition of side reactions under low moisture conditions, and this led to the completion of the present invention. be.

Specifically, the present invention is as follows.

That is, when performing a transesterification reaction of oils and fats using a lipase agent having lipolytic activity, preferably 5 to 100 parts of the lipase agent is used per 100 parts (by weight, the same applies hereinafter) of the above reaction substrate mixture, and the By continuously dehydrating the reaction system from the beginning or during the reaction, it is possible to significantly shorten the time by performing a single reaction without requiring complicated reaction steps, and to increase the yield of the target component by hydrolysis of the substrate. It is possible to further suppress a decrease in the transesterification activity of the lipase agent without causing a decrease, and to increase the number of times of recovery and use as much as possible.

In the present invention, the type of reactor is not particularly limited, and a conventional stirring type batch reactor or packed column type circulation reactor is effective from the viewpoint of dehydration efficiency. Further, a continuous reactor of a falling type or a fluidized bed type can also be used.

As the lipase agent used in the present invention, a heat-resistant immobilized lipase preparation supported on various carriers is preferable. The appropriate amount to use is 5 to 100 parts per 100 parts of fats and oils.
part is preferred. Further, the presence of more lipase agent than necessary is not preferable because it impairs workability due to an increase in the slurry concentration in the reaction system.

The lipases used in the present invention include Rhizopus genus, Aspergillus genus, Chromobacterium genus, Mucor genus, and Pseudomonas genus, which have excellent regioselectivity.
monus), geotrichems with fatty acid specificity (
Examples include lipases originating from microorganisms such as the genus Geot-richum, the genus Candida which shows no specificity, and animal lipases such as pancreatic lipase.

Among these, it is more preferable to use lipases produced by heat-resistant strains of the genus Rhizopus, Pseudomonas, Chromobacterium, Mucor, or Candida.

It is preferable to use lipase by immobilizing it on a known carrier, but examples of immobilizing carriers include transesterification systems such as celite, diatomaceous earth, kaolinite, silica gel, perlite, glass fiber, molecular sieve, activated carbon, and calcium carbonate. Any carrier can be used as long as it does not adversely affect the lipase activity, such as insoluble inorganic carriers and organic polymers such as cellulose powder, ion exchange resins, and chitosan. The carrier may be in various shapes such as powder, fruit, fiber, sponge, etc., and any of these can be used. In particular, it is more desirable if the heat resistance and activity are enhanced by immobilization, and it is particularly preferable to use a lipase immobilized on a macroscopically porous anion exchange resin.

The oils and fats used in the present invention include common vegetable oils,
Examples include animal fats and oils, processed fats and oils, and mixtures thereof. Examples of these include soybean oil, cottonseed oil, rapeseed oil, corn oil, safflower oil, sunflower oil, coconut oil, beef tallow, lard, fish oil, and the like. Furthermore, when the purpose is to produce a cocoa butter substitute fat by transesterification, oils and fats containing a large amount of oleic acid at the 2nd position of the glyceride, such as palm oil, olive oil, high oleic acid sunflower oil, high oleic acid It is possible to use Japanese flower oil, camellia oil, sasanqua oil, monkey butter, shea butter, illipe butter, kokum butter, mora butter, fulwara butter, porneotallow butter, mango kernel oil, or fractionated fats and oils thereof.

Transesterification is carried out by reacting esters with fatty acids, with each other, or with alcohols. The fatty acids include straight chain fatty acids with 2 to 24 carbon atoms that normally exist in nature, such as saturated fatty acids such as palmitic acid, stearic acid, and behenic acid, and oleic acid, linoleic acid, and eicosapencitric acid. Unsaturated fatty acids and the like can also be used.

The reaction temperature in the present invention can be carried out at a temperature of 30 to 90°C, which is slightly higher than that of a normal enzyme reaction. As a method for removing water from the reaction system, it is preferable to reduce the pressure of the reaction system to a water vapor pressure or lower. The degree of reduced pressure is not particularly limited, but is preferably 3 to 150 mm).

It is desirable that the water content in the reaction system at the end of the reaction be 0.03 parts or less (based on 1.0 parts of fats and oils as a substrate) from the viewpoint of suppressing the by-product of diglyceride.

Since rapid dehydration causes a decrease in the reaction rate, the dehydration rate should be between 1.0 Xl0-' and 1.0 Xl0-'. OXl0-”g
/g substrate/Hr is preferable from the viewpoint of maintaining the reaction rate, but is not limited thereto.

Further, if necessary, moisture can be removed from the reaction system by blowing inert gas such as dry nitrogen.

From the reaction mixture after the transesterification reaction, fatty acids,
Small amounts of partial esters such as monoglycerides and diglycerides, unreacted alcohols, etc. can be easily removed by using conventional separation and purification methods such as liquid-liquid extraction, alkali neutralization, vacuum or molecular distillation, alone or in an appropriate combination. can be removed to obtain a purified transesterified product.

〔Effect of the invention〕

The method of the present invention is for fully demonstrating the synthetic activity of lipase, and effectively utilizes the fact that the synthetic activity of lipase is proportional to the enzyme concentration and inversely proportional to the water content.

The greatest effect of the present invention is that when the amount of enzyme used is sufficiently high relative to the oils and fats used as reaction substrates, water that promotes hydrolysis of side reactions can be removed from the reaction system at the beginning or during the reaction. By doing so, it is possible to suppress the increase in by-products without reducing the reaction rate.

The combined effect of the present invention is that by increasing the concentration of the lipase agent in the reaction system sufficiently, a mutual stabilizing effect of the enzymes is expressed, and as a result, the decrease in enzyme activity over time is reduced, and the concentration of the lipase agent recovered after the reaction is reduced. The lipase agent can be effectively reused, and the productivity per weight of enzyme can be significantly improved in industrial scale implementation, thereby improving economic efficiency. Furthermore, if the present invention is applied to transesterification of fats and oils, by using a regioselective lipase agent, an expensive cocoa substitute fat can be effectively produced from, for example, inexpensive palm oil.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples.

Example 1 Palm oil medium melting point (iodine value 30.5, diglyceride 4.
6%) 100 parts and commercially available stearic acid (Lunatsuk S□-
90, stearic acid purity 93%, Kao Corporation type) 10
0 parts, a commercially available heat-resistant immobilized enzyme (lipase of Mucor mlehet origin immobilized on macroscopically porous anion exchange resin, manufactured by Novo Industri A-3, moisture content) 8.0%) was added thereto, and the reaction was carried out at 60° C. and 150 mmWg for 5 hours. Further, the water content in the reaction system at the initial stage of the reaction was 0.045 parts per 1.0 part of the reaction raw materials. After the reaction was completed, the water content was 0.004 part.

After the reaction was completed, the product was collected, and a triglyceride fraction was collected by silica gel column chromatography (Merck, 117735) (developing solvent: n-hexane:
Ethyl ether = 90:10).

The separated triglyceride fraction was analyzed for alkyl group composition by gas chromatography as methyl ester according to the standard oil and fat analysis method. From the amount of stearic acid incorporated into triglycerides by the reaction,
The degree of progress of the transesterification reaction was investigated by calculating the reaction rate when the equilibrium value expressed by the following formula was taken as 100%. The reaction rate at this time was 91.8%, indicating that the reaction was sufficiently performed.

Reaction rate % (time &) = 100X (St-3o)/
(Soo-3o) In the above formula, St: Stearic acid content in fats and oils at time t So:
Stearic acid content in raw material fat before reaction S00: 1
．． 3 Means the stearic acid content at random equilibrium.

In addition, from the sample after the completion of the reaction, Florisil (manufactured by Merck & Co., Ltd.,
1112518) column chromatography to remove fatty acids and reverse phase high performance liquid chromatography (ODS
Silica = Hitachi gel 113750, eluent = acetone:
Glyceride composition was analyzed using acetonitrile).

The diglyceride content after the reaction remained at 4.8%, and the actual increase due to the reaction was only 0.2%.

Comparative Example 1 A reaction was carried out in exactly the same manner as in Example 1, except that the reaction was carried out under normal pressure. The reaction rate after 5 hours was as high as 101%, but the diglyceride value was very high at 25.1%, indicating that the yield of the desired transesterified fat was low and the quality was insufficient. became.

Example 2 In Example 1, instead of running the reaction under reduced pressure, dry nitrogen was bubbled into the headspace at a flow rate of 0.01 v/v/m. As a result of analysis in the same manner as in Example 1, the reaction rate was 91.
4%, diglyceride 9.6%, and sufficient results were obtained similar to the reduced pressure reaction.

Example 3 In Example 2, after 3 hours during the reaction, the reaction system was
The pressure was reduced to 00 mmHH.

The reaction rate after 5 hours was 96.4%, diglyceride was 5.6
%, and a sufficient effect was obtained.

Example 4 In Example 1, a commercially available heat-resistant immobilized enzyme (
Mucor immobilized on macroscopic porous anion exchange resin
Lipase originating from Mucor m1ehei, manufactured by Novo Industri A-S, moisture 8.0%
) was previously dried under reduced pressure to have a water content of 5.5%, and 50 parts thereof were used to carry out the reaction in the same manner as in Example 1, except that the temperature was 70°C.

The reaction rate after 5 hours was 98.1%, and the diglyceride content was 4.1%, which was lower than the diglyceride content of the starting material, confirming that the synthesis was being carried out.

Example 5 The reaction shown below was carried out using the reactor shown in FIG.

That is, a commercially available thermostable immobilized enzyme (Mucor-Mayhei immobilized on a macroscopically porous anion exchange resin) was used.
Mucor m1ehei) origin lipase, manufactured by Novo Industri A-3, water content: 8.0%) was previously dried under reduced pressure to reduce the water content to 6.2%, and 30 g of it was packed into packed tower 1 with an internal capacity of 75 cm. A mixture of 100 g of medium melting point palm oil and 100 g of stearic acid was circulated through the packed tower at 65°C. The liquid passing rate at this time was 0.18 cm/sec as a superficial velocity. Further, a 500-meter receiving tank 3 was directly connected to the bottom of the packed tower 1 to recover the circulating fluid. At this time, the pressure inside the receiving tank 3 was reduced to 160 mmHg. The reaction rate after 5 hours was 90.2%, and the diglyceride content was 9.0%. By continuing circulation until after the reaction for an additional 8 hours,
The reaction rate increased to 96.9% and the diglyceride was 8.1%.
It declined to .

In the reactor shown in FIG. 1, 2, 2'' is a jacket, 4 is a fixed blade, 5 is a stirring blade, 6 is a liquid feeding pump, 7 is a flow meter, and 8 is a pressure gauge.

Further, detailed results of this example are shown in Table 1.

Table 1 Comparative Example 2 The test was carried out in the same manner as in Example 5 except that the pressure inside the receiving tank was kept at normal pressure. The reaction rate after 5 hours was 90.6%, but the production of diglyceride increased over time and reached 18.0% after 5 hours.
It showed a very high value.

The details of this implementation result are shown in Table 2.

Table 2 As can be seen from the above examples, it is a heat-resistant glue.

By using an enzyme preparation containing Base and dehydrating it during a solvent-free reaction, it is possible to maintain both the rate of the transesterification reaction and suppress the by-product diglyceride, making it possible to carry out the process on an industrial scale.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing the reactor (external circulation reactor using a packed column) used in Example 5. 1... Packed tower 2.2゛... Jacket 3... Receiving tank 4... Fixed blade 5... Stirring blade 6... Liquid feed pump 7... Flow meter 8... Pressure gauge Applicant's agent Kaoru Furuya Figure 1

Claims (1)

[Scope of Claims] 1. An enzyme containing a lipase that has heat resistance at a temperature sufficient to melt a reaction substrate or higher in a method for transesterifying oils and fats using an enzyme preparation containing a lipase. A method for transesterification of oils and fats, which uses a preparation, does not use a solvent, and removes water from the reaction system during the reaction. 2. The method for transesterification of oils and fats according to claim 1, wherein the reaction is carried out under reduced pressure to remove water. 3. The method for transesterification of oils and fats according to claim 1, wherein an inert gas is introduced into the reaction system to remove water. 4. The method for transesterification of oils and fats according to any one of claims 1 to 3, in which an immobilized enzyme is used as the enzyme preparation containing a heat-resistant lipase. 5. The method for transesterification of oils and fats according to claim 4, which uses lipase immobilized on a macroscopically porous anion exchange resin as the immobilized enzyme. 6. Claim 1, wherein the lipase is a lipase produced from a heat-resistant strain of Rhizopus, Pseudomonas, Chromobacterium, Mucor, or Candida.
The method for transesterification of oils and fats according to item 5 or item 5.