JP2008263784A - Method for producing branched fatty acid-containing diacylglycerol-containing oil and fat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently produce oils and fats containing a diacylglycerol, having a branched fatty acid as a constituent fatty acid at a high concentration. <P>SOLUTION: The method for producing branched fatty acid-containing diacylglycerol-containing oils and fats includes the step making a monoacylglycerol containing a branched fatty acid as a constituent fatty acid react with a straight-chain fatty acid or its lower alcohol ester, in the presence of lipase under reduced pressure of 0.01-10 kPa. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing fats and oils containing diacylglycerol having a branched fatty acid as a constituent fatty acid at a high concentration.

  Diacylglycerol exhibits properties such as high hydrophilicity compared to triacylglycerol, and is an industrially useful oil and fat. Diacylglycerol is produced by performing an esterification reaction using monoacylglycerol and fatty acid or glycerin and fatty acid as raw materials, or by performing glycerolysis using triacylglycerol (ordinary fats and oils) and glycerin as raw materials. These reactions are classified into chemical methods or enzymatic methods depending on the catalyst used (see Patent Documents 1 to 3). In addition, since the esterification reaction generates water, means for dehydrating the reaction system by reducing the pressure in the reaction system has been adopted to advance the esterification reaction (see Patent Documents 4 and 5).

  Oils and fats containing branched fatty acids as constituent fatty acids have a low melting point. For example, when compared with stearic acid having 18 carbon atoms, the melting point for linear fatty acids is 70 ° C. (Oil and Chemicals Handbook), whereas the melting point for branched fatty acids is −20 ° C. It is. Moreover, it is known that diacylglycerol containing a branched fatty acid as a constituent fatty acid expresses remarkable characteristics in extensibility and crystallinity (Patent Document 6). Furthermore, it is known that diacylglycerol containing a branched fatty acid as a constituent fatty acid has a long lasting moisturizing effect (Patent Document 7). In the method of Reference 7, the esterification reaction is carried out under a vacuum condition of 13 kPa (100 mmHg). Usually, such dehydration is difficult under such a low vacuum, and the reaction takes time. Adopted.

When a monoacylglycerol having a straight chain fatty acid as a constituent fatty acid and an esterification reaction using the straight chain fatty acid as a raw material under a low vacuum, the diacylglycerol is transferred to the triacylglycerol and a high-purity diacylglycerol cannot be obtained. . As a countermeasure in this case, an esterification reaction is performed under a high vacuum, the reaction is promptly performed, the reaction is stopped at a certain reaction rate, and a decrease in diacylglycerol purity is suppressed.
JP-A-1-71495 International Publication No. 03/29392 Pamphlet JP-A-63-133992 JP-A-10-234391 JP 2001-169795 A Japanese Patent Laid-Open No. 1-1101890 JP-A-2-270811

  In the esterification reaction under the above-mentioned high vacuum conditions, a high vacuum equipment is required, so that the equipment load becomes large and high energy is required. In addition, since the purity of diacylglycerol is drastically reduced at a certain high reaction rate of 80% by mass or more, it is difficult to obtain a high reaction rate and high purity diacylglycerol.

  Then, an object of this invention is to provide the fats and oils which contain the diacylglycerol which has a branched fatty acid as a constituent fatty acid at high concentration.

  As a result of examining the above problems, the present inventor has found the following facts. When diacylglycerol is produced by esterification reaction of monoacylglycerol and a fatty acid, 1,2-diacylglycerol is converted into 1,2-diacylglycerol and 2 fatty acids bonded to the 1-position or 3-position of 1,3-diacylglycerol. Those transferred to the position cause a phenomenon that triacylglycerol is further generated by binding of fatty acid, and the purity of diacylglycerol is lowered. On the other hand, when comparing linear and branched fatty acids with the same number of carbon atoms, the branched fatty acids are sterically bulky despite the fact that both have the same molecular weight, and the mobility of the molecules is increased. I found that there is a specificity of getting worse. Therefore, by making the target to be reacted with a fatty acid monoacylglycerol having a branched fatty acid as a constituent fatty acid, it is difficult to change 1,2-diacylglycerol to triacylglycerol, and to the second position in 1,3-diacylglycerol. It has been found that the transfer reaction of fatty acids is difficult to occur. Furthermore, by reacting under specific vacuum conditions, it has been found that diacylglycerol-containing fats and oils having a branched fatty acid as a constituent fatty acid can be produced more efficiently than conventional production methods without applying equipment load, The present invention has been completed.

  That is, the present invention relates to a diacyl having a branched fatty acid in which a monoacylglycerol having a branched fatty acid as a constituent fatty acid and a linear fatty acid or a lower alcohol ester thereof are reacted under reduced pressure of 0.01 to 10 kPa in the presence of lipase. A method for producing a glycerol-containing fat is provided.

  According to the method of the present invention, fats and oils containing diacylglycerol having a branched fatty acid as a constituent fatty acid at a high concentration can be efficiently produced.

In the present invention, it is preferable to use monoacylglycerol having a branched fatty acid bonded to the 1- or 2-position of the glycerin skeleton as one of the substrates. The branched fatty acid is preferably further bonded to the 1-position of the glycerin skeleton. 4-24 are preferable and, as for carbon number of branched fatty acid, 16-22 are more preferable (Hereinafter, the fatty acid couple | bonded with the glycerol skeleton is described as a "constituent fatty acid"). Examples of the branched fatty acid that is a constituent fatty acid include isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, and isostearic acid. Isopalmitic acid and isostearic acid are preferable. In particular, it is preferable to use monoacylglycerol isostearate as a substrate from the viewpoint of obtaining high-purity diacylglycerol in a high yield, and it is also preferable from the viewpoint of making the reaction apparatus small in equipment load and compact.
The straight chain fatty acid or lower alcohol ester thereof as the other substrate is preferably a straight chain fatty acid having 8 to 24 carbon chains. In particular, a straight chain fatty acid having 10 to 14 carbon chains is preferable from the viewpoint of obtaining high-purity diacylglycerol in a high yield. In the case of a lower alcohol ester, the alcohol preferably has 1 to 3 carbon atoms.

  The origin of the linear fatty acid used in the present invention may be vegetable or animal fats. Specific examples of the raw material include fish oil such as bonito oil, sardine oil and tuna oil, vegetable oil such as linseed oil, perilla oil, soybean oil, rapeseed oil and sunflower oil. In addition, those obtained by separating and mixing these oils and fats, and those obtained by adjusting the fatty acid composition by hydrogenation or transesterification can be used as raw materials.

  The molar ratio of the linear fatty acid or its lower alcohol ester used in the present invention to the monoacylglycerol is preferably 0.1 to 10 mol times, more preferably 0.5 to 5 mol times, particularly 1 to 1.5 mol times. Is preferable from the viewpoint of economically obtaining highly pure diacylglycerol.

  In the present invention, lipase is used when a monoacylglycerol having a branched fatty acid as a constituent fatty acid is reacted with a linear fatty acid or a lower alcohol ester thereof. Examples of lipases include those derived from microorganisms of the genus Rhizopus, Aspergillus, Mucor, Geotrichum, Pseudomonas, Penicillium, Chromobacterium, Candida, Achromobacter, or Alcaligenes. Among these lipases, those that selectively act at the 1-position or 3-position of monoacylglycerol are preferred from the viewpoint that particularly useful diacylglycerol can be synthesized. As monoacylglycerol having a branched fatty acid as a constituent fatty acid, 1- (or 3-) monoacylglycerol is stable. In this case, by using a lipase that acts only at the 3-position (or 1-position), the branched fatty acid is used. And diacylglycerol containing linear fatty acid can be obtained very easily with high purity.

  As the lipase used in the present invention, the crude enzyme isolated and purified from the above cells may be used as it is, but from the economical point of view that it can be recovered and reused after the reaction, it is retained on various carriers and immobilized. It is preferable to use the lipase prepared.

  As a carrier for immobilizing lipase, inorganic carriers such as celite, diatomaceous earth, kaolinite, silica gel, molecular sieves, porous glass, activated carbon, calcium carbonate, ceramics, ceramic powder, polyvinyl alcohol, polypropylene, chitosan, ion exchange resin And organic polymers such as hydrophobic adsorption resins, chelate resins, and synthetic adsorption resins. Among them, ion exchange resins are particularly preferable from the viewpoint of water retention. Of the ion exchange resins, a porous surface is preferable because it has a large surface area, and thus a larger amount of adsorption of the enzyme can be obtained.

  The particle diameter of the resin used as the immobilization carrier is preferably 100 to 1000 μm, particularly preferably 250 to 750 μm. The pore diameter is preferably 10 to 150 nm. Examples of the material include phenol formaldehyde, polystyrene, acrylamide, divinylbenzene, and the like, and phenol formaldehyde resin (for example, Duolite A-568 manufactured by Rohm and Hass) is particularly preferable.

  In the present invention, when the lipase is immobilized on the carrier, the temperature at which the lipase is immobilized can be determined according to the characteristics of the enzyme, but 0 to 60 ° C., particularly 5 to 40 at which the enzyme is not deactivated. ° C is preferred. Moreover, the pH of the enzyme solution used at the time of immobilization may be in a range where no denaturation of the enzyme occurs, and can be determined by the characteristics of the enzyme as well as the temperature, but is preferably pH 3-9. In order to maintain this pH, a buffer solution is used. Examples of the buffer solution include an acetate buffer solution, a phosphate buffer solution, and a Tris-HCl buffer solution. The enzyme concentration in the enzyme solution is preferably not more than the saturation solubility of the enzyme and sufficient from the viewpoint of immobilization efficiency. Moreover, the enzyme solution can also use what was refine | purified by the supernatant obtained by removing the insoluble part by centrifugation, ultrafiltration, etc. as needed. Moreover, although the enzyme mass to be used varies depending on the enzyme activity, it is preferably 5 to 1000 parts, more preferably 10 to 500 parts, relative to 100 parts by mass of the carrier (hereinafter simply referred to as “part”).

  When the enzyme is immobilized, the carrier and the enzyme may be directly adsorbed. However, in order to obtain an adsorption state that expresses high activity, the carrier may be treated with a fat-soluble fatty acid or a derivative thereof in advance before the enzyme adsorption. preferable. As a method for contacting the fat-soluble fatty acid or derivative thereof with the carrier, these may be added directly to water or an organic solvent, but in order to improve dispersibility, the fat-soluble fatty acid or derivative thereof is once dispersed and dissolved in the organic solvent. And then added to a carrier dispersed in water. Examples of the organic solvent include chloroform, hexane, ethanol, and the like. The used mass of the fat-soluble fatty acid or derivative thereof is preferably 1 to 500 parts, particularly 10 to 200 parts, relative to 100 parts of the carrier. The contact temperature is preferably 0 to 100 ° C, particularly preferably 20 to 60 ° C, and the contact time is preferably about 5 minutes to 5 hours. The carrier after this treatment is collected by filtration, but may be dried. The drying temperature is preferably room temperature to 100 ° C., and drying under reduced pressure may be performed.

Among the fat-soluble fatty acids or derivatives thereof for treating the carrier in advance, the fat-soluble fatty acid has a saturated or unsaturated, linear or branched, hydroxy group having 4 to 24 carbon atoms, preferably 8 to 18 carbon atoms. Fatty acids that may be used are listed. Specific examples include capric acid, lauric acid, myristic acid, oleic acid, linoleic acid, α-linolenic acid, ricinoleic acid, isostearic acid and the like. Examples of the fat-soluble fatty acid derivatives include esters of these fat-soluble fatty acids with mono- or polyhydric alcohols or saccharides, phospholipids, and those obtained by adding ethylene oxide to these esters. Specific examples include methyl esters, ethyl esters, monoglycerides, diglycerides, ethylene oxide adducts thereof, polyglycerin esters, sorbitan esters, and sucrose esters of the above fatty acids. These fat-soluble fatty acids and derivatives thereof are preferably liquid at room temperature in terms of immobilizing the enzyme on the carrier. As these fat-soluble fatty acids or derivatives thereof, two or more of the above may be used in combination, and naturally derived fatty acids such as rapeseed fatty acids and soybean fatty acids may be used.
The amount of the immobilized lipase is 0.5 to 50 parts, preferably 1 to 100 parts of the total amount of monoacylglycerol and linear fatty acid or lower alcohol ester thereof having a branched fatty acid to be subjected to the reaction as a constituent fatty acid. 20 parts, more preferably 2 to 10 parts, and further 3 to 6 parts are preferred from the viewpoint of reaction time and enzyme cost.

Examples of the reaction include a method in which an enzyme or an immobilized enzyme is suspended in a substrate in a stirring tank, a method in which the substrate is circulated between a fixed bed filled with the immobilized enzyme and a dehydration tank. A method using a stirring tank is preferable from the viewpoint of improving the purity of diacylglycerol. The method using a fixed bed filled with an immobilized enzyme and a dehydration tank is preferable because a process for separating the diacylglycerol after the reaction from the immobilized enzyme is unnecessary and handling properties can be improved.

The pressure of the reaction in the method of the present invention is 0.1 to 10 kPa, preferably 0.2 to 9 kPa, more preferably 0.5 to 8 kPa, particularly 1.5 to 7 kPa, especially 5 to 7 kPa. From the viewpoint of efficiency, high purity of diacylglycerol, and industrialization. Here, the pressure refers to absolute pressure. The pressure is preferably larger from the viewpoint of the equipment cost and operating cost of the vacuum equipment, and preferably smaller from the viewpoint of increasing the purity of the diacylglycerol and shortening the reaction time. It is preferably 0.2 to 9 kPa, more preferably 0.5 to 8 kPa, especially 1.5 to 7 kPa, especially 5 to 7 kPa.
The reaction temperature is preferably 0 to 100 ° C., more preferably 20 to 80 ° C., particularly preferably 30 to 60 ° C. from the viewpoint of improving the reaction rate and suppressing the deactivation of the enzyme.

The reaction rate is preferably 50% by mass (hereinafter simply referred to as “%”) or more, more preferably 60% or more, particularly 70 to 100%, and particularly 80 to 95% for industrial productivity, It is preferable in terms of yield. The purity of diacylglycerol is preferably 70 to 100%, more preferably 75 to 97%, particularly 80 to 96%, and particularly 85 to 95%, for industrial productivity, moisturizing property of fats and oils containing diacylglycerol, It is preferable in terms of processing characteristics.
Here, in the present invention, the total content of diacylglycerol and triacylglycerol in the reaction solution (ester reaction oil) is referred to as “reaction rate (%)”. The diacylglycerol content in the total of diacylglycerol and triacylglycerol is referred to as “diacylglycerol purity (%)”.

  The ester reaction oil obtained by the esterification reaction can be made into a product of diacylglycerol-containing fat by performing post-treatment. The post-treatment is preferably performed by steps such as deoxidation, acid treatment, water washing, decolorization, and deodorization.

Deoxidation is a step of removing unreacted and by-product fatty acids and monoglycerides by distillation under reduced pressure. The acid treatment is a step of adding a chelating agent such as citric acid, mixing and dehydrating under reduced pressure, and further washing with water to remove a trace amount of components such as metals. Washing with water is a process of adding and mixing water to separate oil and water. A decoloring process is a process of improving a hue and flavor by contacting with an adsorbent. Deodorization is a process of improving flavor and hue by thermally decomposing pigment components that are decomposed by heat at the same time as removing odorous substances and low-boiling components by steam distillation under reduced pressure.
These post-treatments can be carried out by selecting the execution and non-execution of each step and the order and conditions of each step according to the degree of purification of the raw material, the composition of the ester reaction oil, and the required quality of the product. .

Since the diacylglycerol content of the diacylglycerol-containing fat after the post-treatment can be estimated from the diacylglycerol purity of the ester reaction oil, the diacylglycerol content of the diacylglycerol-containing fat and oil can be obtained by adjusting the diacylglycerol purity of the ester reaction oil. Can be adjusted to the range.

(Preparation of monoacylglycerol)
A monoacylglycerol having a branched fatty acid as a constituent fatty acid, which is one of the substrates for the reaction, was prepared by the following method.
36 g of isostearic acid (Nissan Chemical Co., Ltd.) and 10 g of glycerin were charged into a 200 mL four-necked flask. Next, 0.1 g of calcium hydroxide was added as a reaction catalyst, and the stirring speed was 400 rpm. The temperature of the liquid part in the flask was raised to 100 ° C. with a temperature controller, and the reaction was carried out for 2 hours. 5 g of 75% strength phosphoric acid aqueous solution was added to make the calcium hydroxide uncatalyzed. After cooling the liquid part in the flask after reaction, it filtered with the filter paper (No. 2). The obtained filtrate was charged into a 300 mL four-necked flask. 100 parts of water was added to 100 parts of the filtrate, followed by stirring at 70 ° C. and 400 rpm. Then, it left still and separated at 70 degreeC, oil and water were divided, glycerol was moved to the water phase side, and glycerol was removed from oil. The oil after removal of glycerin was supplied at a temperature of 180 ° C. and a pressure of 0.4 kPa at a flow rate of 150 mL / H using a thin-film distillation apparatus (55φ × 200H, effective heat transfer area 0.035 m ² ). The condenser was adjusted to 40 ° C. with a temperature controller, and monoacylglycerol was distilled and collected. The recovered oil and fat had a content of monoacylglycerol containing isostearic acid as a constituent fatty acid of 92% and an acid value of 9.8 (mg-KOH / g). The acid value was measured based on the standard oil analysis test method (2.3.1-1996).

[Preparation of immobilized enzyme]
54 g of Duolite A-568 (Rohm and Hass) was stirred in 5 L of N / 10 NaOH solution for 1 hour. After filtration, it was washed with 1 L of distilled water, and the pH was equilibrated with 5 L of 500 mM acetate buffer (pH 5). Thereafter, pH equilibration was performed twice with 5 L of 50 mM acetate buffer (pH 5) every 2 hours. After collecting the carrier by filtration, ethanol substitution with 2.5 L of ethanol was performed for 30 minutes. After filtration, 5 L of an ethanol solution containing 100 g of ricinoleic acid was brought into contact with the carrier for 30 minutes. After filtration, the buffer solution was replaced with 5 L of 50 mM acetate buffer (pH 5) four times for 0.5 hour. After filtration, the enzyme was adsorbed by contacting with 1 L of a 10% strength lipase (Nagase Sangyo Co., Ltd.) solution at room temperature for 4 hours. After adsorption, it was filtered and washed with 5 L of 50 mM phosphate buffer (pH 5) for 0.5 hour. After washing, filtration was performed to recover the immobilized enzyme. The residual water content of the immobilized enzyme at this time was 1.5%.

[Analysis of glyceride composition]
The glyceride composition was analyzed in accordance with the Japan Oil Chemists' Society "Standard Oil Analysis Test Method" (2.4.2.2.-1996).

Example 1
The prepared immobilized enzyme (5.2 g) was charged into a 200 mL four-necked flask. Next, 80 g of the prepared monoacylglycerol was added, the temperature of the reaction solution was adjusted to 52 ° C. with a temperature controller, and 49.3 g of myristic acid was further added while stirring at 200 rpm. Next, the reaction was carried out while adjusting the stirring speed to 500 rpm, adjusting the pressure in the flask to 0.2 to 0.4 kPa, and removing reaction water from the system. During the reaction, the reaction solution was sampled over time, and the reaction was stopped when the acid value of the reaction oil in the reaction solution decreased to 25 mg-KOH / g-reaction oil or less. Table 1 shows the glyceride composition of the reaction oil.

Examples 2-4
The reaction was performed in the same manner as in Example 1 except that the pressure during the reaction in Example 1 was changed to 0.7 to 1.2 kPa, 2 to 3 kPa, or 6 to 7 kPa. The results are shown in Table 1.

Comparative Example 1
The reaction was carried out in the same manner as in Example 1 except that the pressure during the reaction in Example 1 was changed to 12 to 14 kPa. The results are shown in Table 1.

Comparative Example 2
The prepared immobilized enzyme (5.1 g) was charged into a 200 mL four-necked flask. Next, 72.8 g of O-95R (Kao Co., Ltd.) whose main component is monoacylglycerol oleate (monoacylglycerol having a straight chain fatty acid as a constituent fatty acid) is added, and the temperature of the liquid is adjusted with a temperature controller. The temperature was adjusted to 52 ° C., and 49.3 g of myristic acid was further added while stirring at 200 rpm. Next, the reaction was carried out while adjusting the stirring speed to 500 rpm, reducing the pressure in the flask to 0.2 to 0.4 kPa, and removing reaction water from the system. During the reaction, the reaction solution was sampled over time, and the reaction was stopped when the acid value of the reaction oil in the reaction solution decreased to 25 mg-KOH / g-reaction oil or less. The results are shown in Table 1.

Comparative Examples 3 and 4
The reaction was performed in the same manner as in Comparative Example 2 except that the vacuum degree during the reaction of monoacylglycerol and myristic acid in Comparative Example 2 was 0.7 to 1.2 and 6 to 7 kPa. The results are shown in Table 1.

As is clear from Table 1, a monoacylglycerol having a branched fatty acid as a constituent fatty acid and a linear fatty acid react with each other under a reduced pressure of 0.01 to 10 kPa in the presence of lipase. It was found that an ester reaction oil having a high glycerol purity was obtained, and diacylglycerol-containing fats and oils having branched fatty acids could be produced efficiently (Examples 1 to 4).
In order to reduce the load on the vacuum equipment, it is preferable to reduce the degree of vacuum as much as possible (the pressure is increased). However, when the pressure exceeds 10 kPa (Comparative Example 1), the reaction is slow and the reaction time is lengthened. It was found that the reaction rate and the purity of diacylglycerol were low and the industrial productivity was poor.
In addition, when reacting a monoacylglycerol having a linear fatty acid as a constituent fatty acid with a linear fatty acid (Comparative Examples 2 to 4), the reaction rate is increased as the degree of vacuum decreases (the pressure increases). As a result, the purity of diacylglycerol was lowered, and the reaction rate and the diacylglycerol purity tended to be incompatible. On the other hand, in the case of reacting monoacylglycerol having a branched fatty acid as a constituent fatty acid and a linear fatty acid (Examples 1 to 4), the reaction rate is increased as the degree of vacuum is lowered (pressure is increased). It was found that the decrease in the purity of diacylglycerol was small, and the reaction rate and the purity of diacylglycerol were compatible.

Claims (3)

  A diacylglycerol having a branched fatty acid, characterized by reacting a monoacylglycerol having a branched fatty acid as a constituent fatty acid with a linear fatty acid or a lower alcohol ester thereof in the presence of lipase under a reduced pressure of 0.01 to 10 kPa. The manufacturing method of oil containing fat.   The method for producing a diacylglycerol-containing oil or fat having a branched fatty acid according to claim 1, wherein the lipase specifically acts at positions 1 and 3 of monoacylglycerol.   The method for producing a diacylglycerol-containing oil or fat having a branched fatty acid according to claim 1 or 2, wherein the lipase is immobilized.