JP2002088392A - Method for ester interchange of oils or fats - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ester interchange reaction method by which an aimed triglyceride is always stably obtained in a high quality, while inhibiting the production of undesired by-products. SOLUTION: This method for the ester interchange of an oil or fat in the presence of an enzyme is characterized in that the oil or fat as a reactant is selected from oils or fats (triglycerides), fatty acids, and fatty acid esters, and that the acid value of the reactant is 8 to 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for transesterifying fats and oils with an enzyme.

[0002]

2. Description of the Related Art Conventionally, triglycerides have been converted by an enzymatic transesterification reaction between fats and oils and fatty acids or monohydric lower alcohol esters thereof (the lower alcohol esters of fatty acids are referred to as "fatty acid esters" in this specification). Attempts have been made to improve the properties of fats and oils by increasing the concentration of specific triglyceride molecular species. In this reaction, when the water content in the system is high, the amount of diglyceride, which is a product of the hydrolysis reaction, increases. The diglyceride itself not only affects the quality of the converted end product triglyceride, but also triggers the isomerization of triglyceride which occurs as a side reaction during the above reaction.
It can be. In the production of SOS (1,3-di-stearoyl-2-oleoylglycerin) type hard butter with oleic oil and stearic acid or an ester thereof, when the above side reaction occurs, isomer triglyceride SSO is generated, and triglyceride SSS is also generated. Generate.

[0003] Since these triglycerides have a very significant effect on the quality of SOS type hard butter, it is necessary to remove them by means such as fractionation. Solvent fractionation is an effective means for obtaining a fraction enriched with the target triglyceride SOS, but it requires large-scale equipment, which increases costs, and it is preferable to use as little solvent as possible from the viewpoint of work safety. . There is also a proposal to remove the converted triglyceride obtained by the transesterification reaction by a treatment with an enzyme specific to the hydrolysis of diglyceride and / or monoglyceride (for example, Japanese Patent Application Laid-Open No. 62-287). The disadvantage is that it is complicated. Therefore, it is important to minimize the generation of diglyceride, which is the cause.

Since it has been proposed to carry out a transesterification reaction in a reaction system as dry as possible (Japanese Patent Laid-Open No. 57-8787, etc.), various proposals have been made to suppress the formation of diglycerides by controlling the water content of the reaction system. However, when using a free fatty acid as a fatty acid source to be newly introduced and replaced in fats and oils to reduce the water content, the transesterification reaction rate is excessively reduced, so that the amount of water present in the reaction system is reduced. It cannot be reduced much, so that the effects of partial glycerides resulting from the degradation remain. In addition, fatty acids have a problem that the temperature of the reaction system becomes considerably high due to the high melting point thereof.Therefore, it is necessary to use a thermostable enzyme or otherwise introduce an organic solvent into the reaction system to dissolve the fatty acids. It was necessary to lower the temperature of the system. Introducing organic solvents involves considerable investment in equipment and safety.

[0005] On the other hand, when a fatty acid ester is used as a fatty acid source, the reaction system can be constituted at a temperature not so high without introducing an organic solvent, which is extremely advantageous industrially. In this reaction system, the transesterification reaction rate is relatively fast, so it is possible to considerably limit the amount of water present in the reaction system, but still, harmful triglycerides such as SSS can be generated, and the quality is still improved There is room to do so.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transesterification method whereby a desired triglyceride can always be obtained stably with high quality.

[0007]

As a result of intensive studies on various transesterification reaction methods, the present inventors have limited the amount of water in the reaction system, and have conventionally used fats and oils or fatty acids or fatty acids and fatty acid esters as reaction substrates. We reviewed that only alternative combinations had been tried, and adjusted the balance between three types of fats and oils, fatty acids and fatty acid esters to control undesired diglycerides and S
We found that we could control the production of SS triglycerides,
The present invention has been completed.

[0008] That is, the present invention relates to an oil or fat produced by an enzyme whose main constituent is that the oil or fat as a reaction substrate is composed of an oil or fat (triglyceride), a fatty acid or a fatty acid ester, and the acid value of the reaction substrate is 8 to 30. Is a transesterification method.

Any kind of fats and oils, fatty acids and fatty acid esters can be selected as the reaction substrate, but it is selected so that both fatty acid groups of the fatty acids and fatty acid esters are fatty acid groups to be introduced into the fat and oil. The ratio of the sum of the two to the fat is preferably 0.1 to 20 times, preferably 0.3 to 10 times. Typically, in the present invention, the fats and oils used for the substrate are unsaturated at the 2-position, the fatty acid groups of the introduced fatty acids are saturated fatty acids, and the main formed fats and oils are 1,3-saturated 2-unsaturated.

In the present invention, when converting triglycerides by transesterification of fats and oils with enzymes, free fatty acids and fatty acid esters are used in combination as a source of new fatty acids to be introduced and exchanged. Triglyceride (TG), diglyceride (DG), water (H2O) and free fatty acids (FA) coexist in equilibrium.

TG + H2O = DG + F
A

Here, the larger the amount of FA present, the more the rightward hydrolysis reaction for producing FA is suppressed.
Therefore, the hydrolysis reaction is suppressed by the addition of the free fatty acid to the transesterification reaction system between the fat and oil and the fatty acid ester, and the production of diglyceride and thus the production of SSS in the above-described typical example are suppressed without reducing the reaction rate or using a solvent. it can.

The effect increases as the acid value indicating the amount of free fatty acids increases, but when the acid value exceeds 30, the transesterification reaction rate, which is the main reaction, decreases, and the conversion of the target triglyceride also decreases remarkably. On top, crystals of free fatty acids tend to precipitate. In order to prevent this, it is necessary to raise the reaction temperature to near 60 ° C., but the reaction at such a high temperature is generally undesirable because it accelerates the deactivation of the enzyme. Therefore, the acid value of the reaction substrate is preferably 30 or less, particularly preferably 20 or less. When the acid value is smaller than 8, the effect of suppressing hydrolysis is hardly recognized. From the above, the acid value of the substrate is 8 or more, especially when the transesterification is carried out in multiple stages.
0 or more is preferable.

[0014] The smaller the amount of water present, the more the reaction to the right that consumes water, that is, hydrolysis, is suppressed. When the amount of water contained in the reaction substrate exceeds 1800 ppm, even if the acid value of the substrate is within the above range, hydrolysis occurs undesirably, and to achieve the object of the present invention, 1800
It must be below ppm, preferably below 100 ppm.

An ester exchange reaction is carried out by reacting an enzyme with a reaction substrate prepared under the above conditions. The enzyme can be used from any of microorganisms, plants, and animals. For example, it is derived from microorganisms such as Rhizopus delemar, Mucor miehei, and Alcaligenes sp. So-called random lipase, soybean, rice bran, etc., derived from microorganisms such as lipases having selectivity at the position, Aspergillus niger, Candidacylindracea, Geotricum candidum, etc.
There are lipases derived from plants such as castor seeds and animal pancreatic lipases, and it is usually convenient to use commercially available products of these. Examples of such a lipase agent include lipase itself, immobilized lipase obtained by a conventional method such as an adsorption method, an ion or covalent bonding method, an entrapment method, and microorganisms such as mold, yeast, and bacteria capable of producing the lipase. It may be used itself.

According to the method of the present invention, the production of undesired diglycerides and SSS triglycerides can be suppressed, so that the desired triglycerides can be obtained with high quality and stability. Further, the present invention is applied to a multi-stage reaction, that is, the following 1) to 4) are repeated, and in the final cycle, the fatty acids and fatty acid esters are completely distilled off from the reactants without performing the operations of 3) and 4). By obtaining the above fats and oils, it becomes possible to increase the concentration of the target triglyceride only by transesterification without solvent separation. 1) preparing a reaction substrate composed of fats and oils (triglycerides), fatty acids and fatty acid esters, and having an acid value of 8 to 30; 2) performing a transesterification reaction of fats and oils with an enzyme on the reaction substrate; 3) All or part of the fatty acids and fatty acid esters are distilled off from the reaction product by distillation, and 4) Fatty acids and fatty acid esters are added to the remaining distillate to prepare the reaction substrate described in 1).

[0017]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the scope of the present invention is not limited to these examples. In the examples, parts and% mean weight basis. (Example 1) Ethyl stearate (C18 purity 97.8%) and stearic acid (C18 purity 97.2%) were mixed to adjust the acid value to 12.5. For 80 parts of this fatty acid / fatty acid ester mixed composition, deoxidized oil of high oleic sunflower oil (acid value 0.13)
20 parts were added and mixed uniformly. The obtained oil / fat mixture (acid value 10.0) was heated to 110 ° C. under vacuum to dehydrate the water in the oil / fat mixture to 30 ppm. Molecular sieves 3A was added to the dehydrated oil / fat mixture (reaction substrate) to further reduce the water content to 20 ppm. Diatomaceous earth supporting lipase with specificity and transesterification activity
(Immobilized enzyme catalyst) The above reaction substrate was passed through a column packed with 120 g at 40 ° C. at a flow rate of 50 g / hr to carry out a transesterification reaction. 67 hours after the start of the reaction, the composition of the mixed solution after the reaction at the column outlet was analyzed by GLC and HPLC.
The analysis results are shown in Table 1 together with the following Comparative Example 1.

Comparative Example 1 In Example 1, 80 parts of ethyl stearate was used without using stearic acid, and 20 parts of deoxidized oil of high oleic sunflower oil (acid value 0.13) was added to mix oils and fats. Except having prepared the liquid, it carried out similarly to Example 1. The results are shown in Table 1 together with Example 1 above.

[Table 1] + −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− || Example 1 | Comparative Example 1 | Comparative Example 2 | + −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −− + | DG | SOS | SSS | DG | SOS | SSS | DG | SOS | SSS | −− + −−−− ++ −−− + | 2.3% | 62.3% | 0.7% | 3.6% | 61.8% | 2.0% | 3.0% | 62.7% | 1.1% | −−− + −−− + −−−− + −−− + −−− + −−−− + −−− +

(Comparative Example 2) The same procedure as in Example 1 was carried out except that the acid value of the stearic acid / stearic acid ester mixture composition in Example 1 was changed to 4.5 (the acid value of the oil / fat mixture was 3.6). Was. Table 1 shows the results.

Example 2 Ethyl stearate (C18 purity 92.1%) and stearic acid (C18 purity 97.2%) were mixed.
The acid value was adjusted to 15. An oil and fat mixture (acid value 12) prepared by adding 20 parts of a deoxidized oil of high oleic sunflower oil (acid value 0.13) to 80 parts of this stearic acid / stearic acid ester mixture composition was dehydrated by vacuum heating, Further, Molecular Sieves 3A was added to adjust the water content to 20 ppm. Thereafter, a transesterification reaction was performed in the column in the same manner as in Example 1. The fatty acid ester and a part of the fatty acid were removed from the mixed composition after the reaction by distillation, and the glyceride fat was concentrated.

To the concentrated glyceride oil and fat, the fatty acid ester and the fatty acid mixed composition distilled off by the above-mentioned distillation are extremely hardened until the unsaturated fatty acid ester and unsaturated fatty acid become saturated fatty acid ester and saturated fatty acid, and then added. The total acid value was adjusted to 12 again. Then, the water content was readjusted to 20 ppm, and the enzymatic transesterification was performed again in the column.

The resulting recombined mixed composition was subjected to distillation to remove all of the fatty acid esters and fatty acids, thereby obtaining transesterified fat and oil glycerides. The composition analysis results are shown in Table 2 together with Comparative Example 3 below.

Comparative Example 3 The procedure of Example 2 was repeated, except that the acid value of the stearic acid / ethyl stearate mixture composition was changed to 8 (the acid value of the oil / fat mixture was 6.4). went. Table 1 shows the results.

[Table 2] + −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− || Example 2 | Comparative Example 3 | +------------------------------------- | +---+---+--+---+---+---+---+---+ | 1.9% | 68.3% | 1.2% | 1.7% | 2.5% | 64.5% | 2.7% | 1.6% | +---+---+---+--+---+--+---+---+

[0026]

As described above, by making the amount of free fatty acids present in the reaction system at a certain ratio or more, the production of the by-products in the examples is less than that of the comparative examples. It can be seen that this is a transesterification reaction method in which a target triglyceride can always be obtained stably with high quality.

Continued on the front page (72) Inventor Masayuki Fukasawa 4-3 Kinnodai, Taniwara-mura, Tsukuba-gun, Ibaraki Pref. DA10 4H059 BA26 BA30 BA33 BB02 BB03 BC03 BC13 BC48 CA18 CA35 DA04

Claims (3)

[Claims] 1. A transesterification of fats and oils by an enzyme, wherein the fats and oils as reaction substrates are composed of fats and oils (triglycerides), fatty acids and fatty acid esters, and the acid value of the reaction substrates is 8 to 30. Method. 2. The method for transesterifying fats and oils according to claim 1, wherein the water content in the substrate is 1800 ppm or less. 3. The following 1) to 4) are repeated, and in the final cycle, the fatty acids and fatty acid esters are completely distilled off from the reaction product without performing the operations of 3) and 4) to obtain the remaining fats and oils. A method for transesterifying fats and oils. 1) preparing a reaction substrate composed of fats and oils (triglycerides), fatty acids and fatty acid esters, and having an acid value of 8 to 30; 2) performing a transesterification reaction of fats and oils with an enzyme on the reaction substrate; 3) All or part of the fatty acids and fatty acid esters are distilled off from the reaction product by distillation, and 4) Fatty acids and fatty acid esters are added to the remaining distillate to prepare the reaction substrate described in 1).