JP2007099958A - Method for producing fatty acids - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing fatty acids having a low content of trans-unsaturated fatty acids and monoacyl glycerols in the constituting fatty acids and good external appearance with reduced coloring by hydrolyzing fats and oils. <P>SOLUTION: The method for producing fatty acids by hydrolyzing fats and oils comprises partially hydrolyzing fats and oils by high-temperature, high pressure decomposition, and thereafter hydrolyzing the partial hydrolyzate by enzymolysis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing fatty acids by hydrolyzing fats and oils.

  Fatty acids are produced by hydrolyzing fats and oils. As a method for hydrolyzing fats and oils, a high-temperature and high-pressure decomposition method (Patent Document 1) and an enzymatic decomposition method (Patent Document 2) are performed. The former is carried out under high temperature and high pressure conditions, and has the advantage of high productivity. However, if a raw material having a lot of unsaturated fatty acids is used, a large amount of trans unsaturated fatty acids may be produced depending on the conditions. On the other hand, the latter uses an enzyme such as lipase as a catalyst, and the reaction is carried out at a low temperature of 0 to 70 ° C., so that it does not produce a trans-unsaturated fatty acid, but is less productive than the high-temperature high-pressure decomposition method.

  In the high-temperature and high-pressure decomposition method, there is an induction period until decomposition starts at the beginning of the reaction. In order to eliminate or shorten the induction time, glycerides are first used with a 1,3-specific lipase, There is also a technique in which a partially hydrolyzed glyceride is prepared by partial hydrolysis by an enzymatic decomposition method, and then a high temperature high pressure decomposition method is performed (Patent Document 3).

JP 2003-113395 A JP 2000-160188 A Japanese National Patent Publication No. 8-507917

  In recent years, the effects of edible oils on health have attracted attention worldwide, and trans-unsaturated fatty acids, along with saturated fatty acids and cholesterol, increase LDL (bad) cholesterol levels and increase the risk of coronary heart disease. It is scientifically supported that In the United States, approximately 13 million people suffer from coronary heart disease, and more than 500,000 die from coronary heart disease each year. Under these circumstances, in the United States, “Nutrition Facts” (nutritional labeling), in addition to the conventional lipid, saturated fatty acid and cholesterol labeling, will be required to label the content of trans-unsaturated fatty acids from January 1, 2006. It became. In Denmark, it is inevitable that the trans-unsaturated fatty acid concentration of edible oil will be 2.0% by mass or less from 2004, and that it will spread throughout the EU countries. Thus, reduction of the trans unsaturated fatty acid of edible oil is desired worldwide. The monoacylglycerol content in fatty acids produced by hydrolyzing fats and oils is preferably low from the viewpoint of emulsification suppression.

Unrefined raw material fat and oil that omits the deodorizing step has a trans-unsaturated fatty acid content in the constituent fatty acid of 1.5% by mass or less. It will not rise. However, since the color derived from the raw material remains as it is, the appearance of the fatty acids obtained is poor. On the other hand, fatty acids obtained by hydrolysis only by the high-temperature and high-pressure decomposition method have a good appearance when the colored components are decomposed, but the content of trans-unsaturated fatty acids in the constituent fatty acids is high. Moreover, the subject that the monoacylglycerol content also became high became clear.
Accordingly, an object of the present invention is to provide a method for producing fatty acids having a good appearance in which the content of trans-unsaturated fatty acids and monoacylglycerols in the constituent fatty acids is low and the color is reduced by hydrolysis of fats and oils. It is in.

  Therefore, the present inventor conducted various studies on the combination of the high temperature and high pressure decomposition method and the enzymatic decomposition method in the hydrolysis reaction of fats and oils. First, the fats and oils were partially hydrolyzed by the high temperature and high pressure decomposition method, and then the enzymatic decomposition. It was found that fatty acids having a low content of trans-unsaturated fatty acid and monoacylglycerol in the constituent fatty acids and having a good appearance can be produced only when hydrolyzed by the method. It has also been found that the monoacylglycerol content cannot be reduced when the process is carried out in the reverse order.

  That is, the present invention is a method for producing fatty acids by hydrolyzing fats and oils, wherein the fats and oils are partially hydrolyzed by a high-temperature and high-pressure decomposition method, and then hydrolyzed by an enzymatic decomposition method. Is to provide.

  According to the present invention, fatty acids having a good appearance with a low content of trans-unsaturated fatty acids and monoacylglycerols in constituent fatty acids can be produced by hydrolysis of fats and oils.

  The “high temperature and high pressure decomposition method” in the present invention refers to a method of obtaining fatty acids and glycerin by adding water to a raw oil and fat and reacting under conditions of high temperature and high pressure. The “enzymatic degradation method” in the present invention refers to a method of obtaining fatty acids and glycerin by adding water to raw oil and fat, using an enzyme such as lipase as a catalyst, and reacting under low temperature conditions. Furthermore, “fatty acids” in the present invention include not only fatty acids but also those in which glycerin, monoacylglycerol, diacylglycerol, and triacylglycerol are present.

  In the present invention, the raw oil / fat to be hydrolyzed may be a vegetable oil / animal fat / oil. Specific examples of the raw material include rapeseed oil, sunflower oil, corn oil, soybean oil, linseed oil, rice oil, safflower oil, cottonseed oil, beef tallow, fish oil and the like. In addition, those obtained by separating and mixing these fats and oils, those obtained by adjusting the fatty acid composition by hydrogenation, transesterification, etc. can be used as raw materials. It is preferable from the viewpoint of reducing the content of trans-unsaturated fatty acid in the fatty acid.

  In the embodiment of the present invention, it is preferable to remove the solid content other than the oil component by filtration, centrifugation, or the like after squeezing the raw material oil from the plant or animal as the respective raw material. Next, it is preferable to degum by separating the gum by centrifugation or the like after adding water and optionally further acid and mixing. Moreover, after adding and mixing an alkali, it is preferable to deoxidize raw material fats by washing with water and dehydrating. Furthermore, it is preferable to decolorize raw material fats and oils by contacting with an adsorbent such as activated clay and then separating the adsorbent by filtration or the like. These processes are preferably performed in the above order, but the order may be changed. In addition to this, the raw oil and fat may be subjected to wintering for separating the solid content at a low temperature in order to remove the wax content. Furthermore, you may deodorize raw material fats and oils by making it contact with water vapor | steam under reduced pressure as needed. At this time, it is preferable to make the heat history as low as possible from the viewpoint of reducing the content of trans-unsaturated fatty acids in the fatty acids constituting the fats and oils. As for the conditions of the deodorizing step, the temperature is preferably controlled to 300 ° C. or less, particularly 270 ° C. or less, and the time is preferably 10 hours or less, particularly 5 hours or less.

  In the present invention, the raw fats and oils have a trans-unsaturated fatty acid content in the constituent fatty acids of 1.5% by mass or less, more preferably 1% by mass or less, particularly 0.5% by mass or less. It is preferable from the viewpoint of reducing the content of trans-unsaturated fatty acids in the constituent fatty acids of the fatty acids. For example, as raw material fats and oils, it is preferable to use undeodorized fats and oils for all or part of the raw materials because trans unsaturated fatty acids in fatty acids constituting fatty acids can be reduced. Here, the trans-unsaturated fatty acid content in the constituent fatty acid is the content in the total amount when two or more fats and oils are used.

  In the hydrolysis by the high-temperature and high-pressure decomposition method, the higher the degree of unsaturation of the constituent fatty acids of the raw material fats and oils, the easier it is to convert to heat. In particular, in the case of oleic acid having an unsaturation degree of 1, almost no trans-transformation occurs upon heating, and in the case of fatty acids having an unsaturation degree of 2 or more, such as linoleic acid or linolenic acid, trans-translation is remarkable. Become.

The raw fat and oil used in the production method of the present invention has a trans-unsaturated fatty acid content in the constituent fatty acid of 1.5% by mass or less, more preferably 0.01 to 1% by mass, and particularly 0.1 to 1% by mass. It is preferable from the viewpoint of physiological effects. The hue C is preferably 20 or more and more preferably 35 or more from the viewpoint that the effect of improving the appearance according to the present invention is remarkable.
The “content of trans-unsaturated fatty acid in the constituent fatty acid” and the “fatty acid composition” in the present invention are the “preparation method of fatty acid methyl ester” (2.4 1.2-1996) ”refers to a value obtained by preparing a fatty acid methyl ester according to American Oil Chemists. Society Official Method Ce 1f-96 (GLC method). The “hue C” of the raw oil or fat or fatty acid is a value obtained by the following equation (1) measured by a 5.25 inch cell according to American Oil Chemists. Society Official Method Ca 13e-92 (Lovibond method). .
C = 10R + Y (1)
(Where R = Red value, Y = Yellow value)

  In the present invention, the hydrolysis of fats and oils by the high-temperature and high-pressure decomposition method can be carried out batchwise, continuously, or semi-continuously, and the supply of raw oils and fats into the apparatus is a cocurrent flow type, countercurrent flow type. Either may be used, and the reaction is performed under the following reaction conditions. As the raw material fat and water to be supplied to the hydrolysis reaction apparatus, it is preferable from the viewpoint of suppressing the oxidation of the fat and oil to use raw material fat and water that have been deaerated or deoxygenated in advance if necessary.

  In the hydrolysis by the high-temperature and high-pressure decomposition method, water is added so as to be 10 to 250 parts by mass with respect to 100 parts by mass of fats and oils, and the temperature is 200 to 270 ° C. and the pressure is 2 to 8 MPa for 0.1 to 6 hours. It is preferable to hydrolyze it over time. The temperature is preferably 210 to 265 ° C, and more preferably 215 to 260 ° C, from the viewpoint of suppressing industrial productivity of fatty acids, decolorization, and generation of trans-unsaturated fatty acids. From the same point, the amount of water relative to 100 parts by mass of the fat is preferably 15 to 150 parts by mass, particularly 20 to 120 parts by mass. Further, from the same point, the pressure is preferably 2 to 7 MPa, particularly preferably 2.5 to 6 MPa. Further, from the same point, the reaction time is further preferably 0.2 to 5 hours, particularly 0.3 to 4 hours.

As a preferable reaction apparatus, a counter-current Colgate-Emery method oil decomposition tower (for example, IHI) equipped with a hydrolysis reaction tank having a capacity of 7 to 40 m ³ can be exemplified. In addition, a commercially available autoclave apparatus (for example, Nitto High Pressure Co., Ltd.) may be used as a hydrolysis reaction tank for laboratory-scale small-scale decomposition.

The hydrolysis reaction of fats and oils under high temperature and high pressure conditions is controlled by the fatty acid concentration, and may be terminated when a predetermined fatty acid concentration is reached. In addition, the “fatty acid concentration” in the present invention refers to a value obtained by measuring the acid value and fatty acid composition of fatty acids according to the knowledge of fats and oils products (Yukishobo Co., Ltd.) and calculating by the following formula (2). The acid value is measured by American Oil Chemists. Society Official Method Ca 5a-40.
Fatty acid concentration (mass%) = xxy / 56.1 / 10 (2)
(X = acid value [mg KOH / g], y = average molecular weight determined from fatty acid composition)

  The partial hydrolysis of fats and oils by the high-temperature high-pressure decomposition method has a fatty acid concentration of 0.5 to 90% by mass from the viewpoint of industrial productivity, good appearance, and suppression of the production of trans-unsaturated fatty acids and monoglycerides. It is preferable to carry out until it becomes 5-85 mass%, especially 20-70 mass%. As a result of partial hydrolysis, the hue C is preferably 35 or less, more preferably 1 to 30, particularly preferably 5 to 25, and the content of trans-unsaturated fatty acids in the constituent fatty acids is 0 to 1.5% by mass, and further preferably It is preferably 1 to 1.2% by mass, particularly preferably 0.2 to 0.7% by mass. Further, the monoglyceride is preferably 1 to 20% by mass, more preferably 1 to 15% by mass, and particularly preferably 3 to 10% by mass.

In the present invention, it is necessary to hydrolyze fats and oils by enzymatic decomposition after partial hydrolysis by high temperature and high pressure decomposition.
In the embodiment of the present invention, lipase is preferable as the fat and oil-decomposing enzyme used in the enzymatic decomposition method. As the lipase, not only animal-derived and plant-derived lipases but also commercially available lipases derived from microorganisms, and also immobilized enzymes on which lipases are immobilized can be used. For example, the enzymes for decomposing fats are Rizopus genus, Aspergillus genus, Chromobacterium genus, Mucor genus, Pseudomonas genus, Geotrichum genus, Penicillium (Penicillium) Examples include lipases originating from microorganisms such as the genus and Candida, and animal lipases such as pancreatic lipase. In order to obtain a high decomposition rate, a lipase having no position specificity (random type) is good, and the genus Pseudomonas, Candida and the like are good.

  In the embodiment of the present invention, the hydrolysis of fats and oils by the enzymatic degradation method is preferably from the viewpoint that the enzyme activity can be effectively used by using an immobilized enzyme in which the enzyme is immobilized on a carrier. As the immobilized enzyme, it is preferable to use a lipase supported on an immobilized carrier. Immobilization carriers include celite, diatomaceous earth, kaolinite, silica gel, molecular sieves, porous glass, activated carbon, calcium carbonate, ceramics and other inorganic carriers, ceramic powder, polyvinyl alcohol, polypropylene, chitosan, ion exchange resin, hydrophobic adsorption Examples include organic polymers such as resins, chelate resins, and synthetic adsorption resins, and ion exchange resins are preferred from the viewpoint of water retention. Of the ion exchange resins, a porous surface is preferable from the viewpoint that a large amount of lipase can be adsorbed by having a large surface area.

  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.

  When immobilizing an enzyme, the enzyme may be directly adsorbed on a carrier. However, in order to achieve an adsorption state that expresses high activity, the carrier is treated with a fat-soluble fatty acid or its derivative before the enzyme adsorption. May be. Examples of the fat-soluble fatty acid to be used include saturated or unsaturated, linear or branched fatty acids having 8 to 18 carbon atoms, which may be substituted with a hydroxyl group. Specific examples include capric acid, lauric acid, myristylic acid, oleic acid, linoleic acid, α-linolenic acid, ricinoleic acid, isostearic acid and the like. Examples of the derivatives include esters of these fatty acids with mono- or polyhydric alcohols, phospholipids, and derivatives 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. Two or more of these fat-soluble fatty acids or derivatives thereof may be used in combination.

  As a method for contacting these fat-soluble fatty acids or derivatives thereof with a carrier, these may be added directly to a carrier in water or an organic solvent, but in order to improve dispersibility, a fat-soluble fatty acid or derivative thereof is added to an organic solvent. Once dispersed and dissolved, it may be added to a carrier dispersed in water. Examples of the organic solvent include chloroform, hexane, ethanol, and the like. The amount of the fat-soluble fatty acid or derivative thereof used is preferably 1 to 500 parts by mass, more preferably 10 to 200 parts by mass with respect to 100 parts by mass of the carrier. The contact temperature is preferably 0 to 100 ° C., more 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.

  The temperature at which the enzyme is immobilized can be determined depending on the characteristics of the enzyme, but is preferably a temperature at which the enzyme is not deactivated, that is, 0 to 60 ° C., more preferably 5 to 40 ° C. 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 enzyme characteristics 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 by mass, more preferably 10 to 500 parts by mass with respect to 100 parts by mass of the carrier.

  Soybean oil that becomes a reaction substrate without drying after recovering the immobilized enzyme by removing it from the enzyme solution by filtration from the point of making it suitable for the hydrolysis reaction after immobilization of the enzyme It is preferable to contact the oil and fat. The water content in the immobilized enzyme after contact varies depending on the type of carrier used, but is 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, particularly 5 to 50 parts by weight, based on 100 parts by weight of the immobilized carrier. Preferably there is. At this time, it may be sealed in a packed container such as a column and the oil and fat may be circulated by a pump or the like, or the immobilized enzyme may be dispersed in the oil and fat. The contact temperature is preferably 20 ° C. to 60 ° C., and can be selected according to the characteristics of the enzyme. Furthermore, the contact time may be about 1 hour to 48 hours, and it is preferable from the viewpoint of industrial productivity that the immobilized enzyme is recovered by filtration after the contact is completed.

  The hydrolysis activity of the immobilized enzyme is preferably 20 U / g or more, more preferably 100 to 10,000 U / g, and particularly preferably 500 to 5000 U / g. Here, 1 U of the enzyme is an enzyme that produces 1 μmol of free fatty acid per minute when hydrolyzed for 30 minutes at 40 ° C. while stirring and mixing a mixture of oil: water = 100: 25 (mass ratio). Shows the resolution.

  In the present invention, the hydrolytic hydrolysis of fats and oils can be carried out batchwise, continuously, or semi-continuously, and the supply of partially hydrolyzed fatty acids and water into the apparatus is cocurrent. Either the formula or the countercurrent type may be used, and the reaction is carried out under the following reaction conditions. The partially hydrolyzed fatty acids supplied to the hydrolysis reaction apparatus are preferably degassed or deoxygenated in advance from the viewpoint of inhibiting oxidation of the fatty acids.

  The amount of immobilized enzyme used for the reaction of the enzymatic decomposition method can be appropriately determined in consideration of the activity of the enzyme, but is 0.01 to 30 parts by mass, and further 0.1 to 100 parts by mass of the fatty acids to be decomposed. ˜15 parts by mass, particularly 0.2 to 10 parts by mass is preferable. The amount of water is preferably 10 to 200 parts by mass, more preferably 20 to 100 parts by mass, and particularly preferably 30 to 80 parts by mass with respect to 100 parts by mass of the fatty acids to be decomposed. The water may be any of distilled water, ion exchange water, tap water, well water and the like. Other water-soluble components such as glycerin may be mixed. If necessary, a buffer solution having a pH of 3 to 9 may be used so that the stability of the enzyme can be maintained.

  The partially hydrolyzed fatty acids used for the enzymatic degradation reaction of fats and oils may be used as they are, but if necessary, the fatty acids and the aqueous phase are separated by a method such as stationary separation and centrifugation, and further the oil phase The glycerin distributed therein may be removed and purified by centrifugation, washing with water or the like.

  The reaction temperature is preferably 0 to 70 ° C., more preferably 20 to 50 ° C., which is a temperature at which the activity of the enzyme is more effectively extracted and free fatty acids generated by decomposition do not become crystals. The reaction is preferably carried out in the presence of an inert gas so that contact with air is avoided as much as possible.

  The hydrolysis reaction is controlled by the fatty acid concentration represented by the above formula (2), and may be terminated when a predetermined fatty acid concentration is reached. After completion of the hydrolysis reaction, the fatty acids and the aqueous phase are preferably separated by a method such as stationary separation or centrifugation. Furthermore, the glycerin distributed in the oil phase may be removed and purified by centrifugation, washing with water or the like.

  In the present invention, as described above, in the hydrolysis reaction of fats and oils, 10 to 250 parts by weight of water is added to 100 parts by weight of the fats and oils, and the temperature is 0. Hydrolyzed partially for 1 to 6 hours, and then added to 0.01 to 30 parts by weight of immobilized enzyme and 10 to 200 parts by weight of water for 100 parts by weight of partially hydrolyzed fatty acids. By hydrolyzing under conditions of a temperature of 0 to 70 ° C., industrial productivity, good appearance, trans-unsaturated fatty acids and fatty acids with reduced monoacylglycerol content can be obtained.

[Immobilized enzyme production method]
50 g of Duolite A-568 (Rohm & Hass) was stirred in 500 mL of 0.1N aqueous sodium hydroxide for 1 hour. Then, it was washed with 500 mL of distilled water for 1 hour, and the pH was equilibrated with 500 mL of 500 mM phosphate buffer (pH 7) for 2 hours. Thereafter, the pH was equilibrated twice with 500 mL of 50 mM phosphate buffer (pH 7) for 2 hours each. Thereafter, filtration was performed to recover the carrier, followed by ethanol replacement with 250 mL of ethanol for 30 minutes. After filtration, 250 mL of ethanol containing 50 g of ricinoleic acid was added and ricinoleic acid was adsorbed on the carrier for 30 minutes. Thereafter, filtration was performed to recover the carrier, followed by washing with 250 mL of 50 mM phosphate buffer (pH 7) four times, ethanol was removed, and the carrier was recovered by filtration. Thereafter, the mixture was brought into contact with 1000 mL of a 10% solution of lipase (Lipase AY “Amano” 30G, Amano Enzyme Co., Ltd.) acting on commercially available fats and oils for immobilization. After filtration, the immobilized enzyme was recovered and washed with 250 mL of 50 mM acetate buffer (pH 7) to remove non-immobilized enzyme and protein. All the above operations were performed at 20 ° C. The immobilization rate was determined to be 95% from the residual activity of the enzyme solution after immobilization and the activity difference between the enzyme solution before immobilization. Thereafter, 200 g of soybean oil was added and stirred at 40 ° C. for 2 hours, followed by filtration to separate from soybean oil to obtain an immobilized enzyme. The immobilized enzyme thus obtained was washed and filtered with partially hydrolyzed fatty acids, which are substrates for actual reaction before use.

[Raw oil]
As raw material fats and oils, undeodorized soybean oil shown in Table 1 was used. The glyceride composition was measured by the following method.
[Method for measuring glyceride composition]
To a glass sample bottle, 10 mg of a sample and 0.5 mL of a trimethylsilylating agent (“silylating agent TH”, manufactured by Kanto Chemical Co., Inc.) were added, sealed, and then heated at 70 ° C. for 15 minutes. Distilled water (1.0 mL) and hexane (2.0 mL) were added thereto, and after mixing, the hexane layer was measured by gas chromatography (GLC).
Apparatus: Hewlett Packard 6890 type column; DB-1HT (manufactured by J & W Scientific) 7m
Column temperature; initial = 80 ° C., final = 340 ° C.
Temperature rising rate = 10 ° C./min, hold at 340 ° C. for 20 minutes Detector; FID, temperature = 350 ° C.
Injection part; split ratio = 50: 1, temperature = 320 ° C.
Sample injection volume: 1 μL
Carrier gas; helium, flow rate = 1.0 mL / min

[Hydrolysis by high-temperature and high-pressure decomposition method]
The raw oil and fat were continuously fed from the lower side of the apparatus and water from the upper side of the apparatus to the oil-water countercurrent type high-pressure hydrothermal decomposition apparatus. The liquid feeding amount was 50 parts by mass of water with respect to 100 parts by mass of the raw material fat. At this time, the average residence time (hr) in the decomposition tower (column volume (m ³ ) / (flow rate of raw material oil (m ³ / hr) + flow rate of water (m ³ / hr))) was about 4 hr. . In the apparatus, the raw oil and fat was heated with high-pressure hot water (5.0 MPa, 240 ° C.). The reaction solution was appropriately collected from a sampling port in the middle of the oil-water counter-flow type high-pressure hydrothermal decomposition apparatus, and cooled to 25 ° C. in a nitrogen sealed and light-shielded state. Thereafter, the mixture was centrifuged (5,000 g, 30 minutes), the aqueous layer was removed, and then the fatty acid layer was dehydrated under reduced pressure at a temperature of 70 ° C. and a vacuum degree of 400 Pa for 30 minutes to obtain Samples A to E. Table 2 shows the analytical value of each fatty acid.

[Hydrolysis by enzymatic decomposition (1)]
Samples A to D, which are partially hydrolyzed fatty acids, and undeodorized soybean oil shown in Table 1 were hydrolyzed by an enzymatic decomposition method using an immobilized enzyme. Samples A to D or 5 g (dry weight) of each immobilized enzyme (hydrolysis activity 2700 U / g) washed with non-deodorized soybean oil were weighed into a 300 mL four-necked flask. To each of them, corresponding samples A to D or 100 g of undeodorized soybean oil and 60 g of distilled water were added and stirred at 40 ° C. in a nitrogen atmosphere in a sealed state (half moon blade φ60 mm × H15 mm: 250 r / min). However, the reaction was continued until the fatty acid concentration of the fatty acids reached 93% by mass or more. The reaction solution was centrifuged (5,000 × g, 30 minutes), the aqueous layer and the immobilized enzyme were removed, and the fatty acid layer was dehydrated under reduced pressure at a temperature of 70 ° C. and a vacuum degree of 400 Pa for 30 minutes to obtain fatty acids (Sample F). To J). Table 3 shows the analytical values of fatty acids (using immobilized enzyme). Here, each sample is obtained by hydrolyzing A for F, B for G, C for H, D for I, and undeodorized soybean oil for J.

[Hydrolysis by enzymatic degradation method (2)]
Samples A to D, which are partially hydrolyzed fatty acids, and undeodorized soybean oil shown in Table 1 were hydrolyzed by an enzymatic decomposition method using a powder enzyme. Samples A to D or 100 g of non-deodorized soybean oil and 55 g of distilled water were weighed into a 300 mL four-necked flask. Thereto, 0.1 g of lipase OF (origin: Candida cylindracea famous sugar industry) was dissolved in 5 g of distilled water, added in its entirety, and stirred in a sealed state in a nitrogen atmosphere at 40 ° C. (half moon blade φ60 mm × H15 mm: 250 r / min), the reaction was continued until the fatty acid concentration of the fatty acids reached 93% by mass or more. The reaction solution is centrifuged (5,000 × g, 30 minutes), and after removing the aqueous layer and the intermediate layer containing powder lipase, the fatty acid layer is dehydrated under reduced pressure at a temperature of 70 ° C. and a vacuum of 400 Pa for 30 minutes. (Samples K to O) were obtained. Table 4 shows analytical values of fatty acids (use of powder lipase). Here, each sample is obtained by hydrolyzing A for K, B for L, C for M, D for N, and undeodorized soybean oil for O.

As is clear from Tables 2 to 4, when the raw fats and oils are partially hydrolyzed under high temperature and high pressure conditions, the fatty acid concentration of fatty acids is 0.5 to 90% by mass, and then hydrolyzed with lipase. Thus, it was found that fatty acids having good appearance (samples G, H, I, L, M, and N) can be obtained with a lower content of trans-unsaturated fatty acid and monoacylglycerol in the constituent fatty acids.
In contrast, fatty acids (sample E) obtained by hydrolysis of raw material fats and oils only by hydrolysis under high temperature and high pressure conditions have a good appearance, but the content of trans-unsaturated fatty acids and monoacylglycerols in the constituent fatty acids It turned out to be expensive. Fatty acids obtained by partially hydrolyzing the raw oil and fat under high temperature and high pressure conditions to make the fatty acid concentration of fatty acids 90% by mass or more and then hydrolyzing with lipase (samples F and K) Was found to have a good appearance and a low monoacylglycerol content, but a high content of trans-unsaturated fatty acids in the constituent fatty acids.
Furthermore, it was found that the fatty acids (samples J and O) obtained from the raw fats and oils only by the enzymatic hydrolysis reaction have low trans-unsaturated fatty acid content and monoacylglycerol content in the constituent fatty acids, but the appearance is impaired. .

Claims (3)

  A method for producing fatty acids by hydrolyzing fats and oils, wherein the fats and oils are partially hydrolyzed by a high-temperature and high-pressure cracking method and then hydrolyzed by an enzymatic degradation method.   The method for producing fatty acids according to claim 1, wherein the hydrolysis by the high-temperature and high-pressure decomposition method is performed until the fatty acid concentration becomes 0.5 to 90% by mass.   The method for producing fatty acids according to claim 1 or 2, wherein the content of trans-unsaturated fatty acids in the constituent fatty acids of the fats and oils subjected to the hydrolysis reaction is 1.5% by mass or less.