JP7065581B2 - Method for producing fatty acids - Google Patents

Description

The present invention relates to a method for producing saturated fatty acids or unsaturated fatty acids by naturally separating raw material fatty acids.

Fatty acids are widely used as intermediate raw materials for foods, additives for various other industrial products, and intermediate raw materials. Such fatty acids are generally produced by hydrolyzing vegetable oils such as rapeseed oil and soybean oil and animal oils such as beef tallow.
However, the fatty acids obtained by hydrolyzing fats and oils are not always suitable as industrial raw materials with the fatty acid composition as it is. That is, it is necessary to separate unsaturated fatty acids and saturated fatty acids according to the purpose of use.

For the separation of fatty acids, a pressing method, a solvent separation method, a natural separation method (dry separation method), and a wetting agent separation method are known. Among them, the natural fractionation method using polyglycerin fatty acid ester (for example, Patent Documents 1 and 2) is a preferable method from the viewpoint of separation efficiency, safety and economy.

Japanese Unexamined Patent Publication No. 2005-146098 Japanese Unexamined Patent Publication No. 2004-67998

When natural sorting is performed at the commercial level, it is necessary to strongly stir the raw material fatty acids for rapid cooling because the sorting tank becomes huge, but if the stirring conditions become strict, crystal growth is hindered and filterability There is a problem that it is easy to decrease. On the other hand, in Patent Document 1, the filterability is improved by using a polyglycerin fatty acid ester having a high degree of glycerin polymerization, but according to the present inventor, the mixture is further stirred strongly from the viewpoint of efficiency. However, it was found that the filtration rate was greatly reduced when the separation was performed.
Therefore, an object of the present invention is to provide a method for efficiently producing desired fatty acids by improving the filterability even under strong stirring conditions when naturally separating the raw material fatty acids.

As a result of diligent research focusing on the fatty acid composition of the raw material fatty acids to be separated and the polyglycerin fatty acid ester, the present inventor has made a specific relationship between the two, even under strong stirring conditions. We have found that high filtration rates can be maintained.

That is, the present invention is a step of adding and mixing polyglycerin fatty acid ester to raw material fatty acids, then cooling with stirring at a peripheral speed of 1.0 to 3.0 m / s to precipitate crystals, and then solid-liquid separation. A method for producing a saturated fatty acid or an unsaturated fatty acid containing
The melting point of the polyglycerin fatty acid ester is 25 to 40 ° C., and the content mass ratio x of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acids constituting the polyglycerin fatty acid ester, and the raw material fatty acids. The present invention provides a production method in which the content mass ratio y of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acid composition of the above satisfies the relationship of the following formula (1).
0.8 ≤ y / x ≤ 1.7 ... (1)

According to the present invention, since the filterability is excellent even under strong stirring conditions, the raw material fatty acids can be efficiently and naturally separated, and the desired fatty acids can be efficiently obtained.

The present invention includes a step of adding and mixing polyglycerin fatty acid ester to raw material fatty acids, then cooling with stirring at a peripheral speed of 1.0 to 3.0 m / s to precipitate crystals, and then solid-liquid separation. A method for producing saturated fatty acids or unsaturated fatty acids.
The melting point of the polyglycerin fatty acid ester is 25 to 40 ° C., and the content mass ratio x of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acids constituting the polyglycerin fatty acid ester, and the raw material fatty acids. This is a production method in which the content mass ratio y of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acid composition of the above satisfies the relationship of the following formula (1).
0.8 ≤ y / x ≤ 1.7 ... (1)
In the present specification, the fatty acid composition of the raw material fatty acid and the polyglycerin fatty acid ester is described in the method described in [Analytical Method] (i) described later, and the melting point of the polyglycerin fatty acid ester is described in [Analytical Method] (ii). Each can be obtained according to the method described above.

The raw material fatty acids to be sorted are produced by hydrolyzing the raw material fats and oils. The hydrolysis method may be either a high-temperature high-pressure decomposition method or an enzymatic decomposition method. Raw oils and fats are vegetable oils and fats such as soybean oil, rapeseed oil, perilla oil, flaxseed oil, egoma oil, chia seed oil, sachainchi oil and algae oil; animal oils and fats such as fish oil, lard, beef oil and butter oil; or their esters. Examples thereof include oils and fats such as replacement oil, hydrogenated oil, and fractionated oil. These fats and oils may be used alone or in combination of two or more.

The raw material fatty acids may contain fats and oils in addition to fatty acids. The substances constituting the fat (oil) include triglyceride (TAG), monoglyceride (MAG), and diglyceride (DAG).
The concentration of free fatty acids in the raw material fatty acids is preferably 50% by mass or more, more preferably 85% by mass or more, and further preferably 93% by mass, from the viewpoint of effectively exerting the effect of the present invention. The free fatty acid concentration refers to a value obtained according to the methods described in [Analytical Method] (iii) and (iv) described later.

The content of saturated fatty acids in the fatty acid composition of the raw material fatty acids is preferably 5 to 60% by mass, more preferably 8 to 50% by mass, from the viewpoint of filterability and filtration efficiency. The saturated fatty acid is preferably a saturated fatty acid having 12 to 24 carbon atoms and further preferably 14 to 22 carbon atoms.
Further, the sum of the contents of the saturated fatty acid having 16 carbon atoms and the saturated fatty acid having 18 carbon atoms in the fatty acid composition of the raw material fatty acids is 5 to 60% by mass, further 8 from the viewpoint of interaction with the polyglycerin fatty acid ester. It is preferably ~ 50% by mass.

The polyglycerin fatty acid ester used in the present invention is obtained by esterifying polyglycerin and a fatty acid.
The fatty acid esterified with polyglycerin is preferably composed of saturated or unsaturated fatty acids having 10 to 22 carbon atoms and 12 to 18 carbon atoms. The fatty acid may be composed of only a single fatty acid, but it is preferable that the fatty acid is composed of a mixed fatty acid from the viewpoint of large growth of crystals and improvement of filterability.

The melting point of the polyglycerin fatty acid ester is 25 to 40 ° C., but it is preferably 27 to 38 ° C. from the viewpoint of promoting the crystallization and growth of the raw material fatty acids.

The average degree of polymerization of glycerin in the polyglycerin fatty acid ester is not particularly limited, but is preferably 15 to 50, more preferably 20 to 45, and further preferably 25 to 40 from the viewpoint of obtaining crystals that can be easily filtered. .. The "average degree of polymerization of glycerin" means a value obtained by measuring the degree of polymerization of the polyglycerin portion of the polyglycerin fatty acid ester by GPC.

In the present invention, the content mass ratio of the saturated fatty acid (P) having 16 carbon atoms to the saturated fatty acid (S) having 18 carbon atoms in the fatty acids constituting the polyglycerin fatty acid ester [(P) / (S)], that is, x and The content mass ratio [(P) / (S)] of the saturated fatty acid (P) having 16 carbon atoms to the saturated fatty acid (S) having 18 carbon atoms in the fatty acid composition of the raw material fatty acids, that is, y is the following formula (1). Meet the relationship.
0.8 ≤ y / x ≤ 1.7 ... (1)
When the value [y / x] of y with respect to x is within such a range, a high filtration rate can be maintained even if fractionation is performed with stronger stirring as compared with Patent Document 1.
The value [y / x] of y with respect to x is 0.9 or more and 1.7 or less, and further 0.9 or more and 1.6 or less, from the viewpoint of the interaction between the raw material fatty acid and the polyglycerin fatty acid ester. preferable.

The content of saturated fatty acids in the fatty acids constituting the polyglycerin fatty acid ester is preferably 20% by mass or more, more preferably 30 to 100% by mass, and further 40 to 40% in terms of interaction with raw material fatty acids and melting point. It is more preferably 95% by mass, more preferably 50 to 90% by mass. The saturated fatty acid is preferably a saturated fatty acid having 12 to 22 carbon atoms and further preferably 12 to 18 carbon atoms.
Further, the sum of the contents of the saturated fatty acid having 16 carbon atoms and the saturated fatty acid having 18 carbon atoms in the fatty acids constituting the polyglycerin fatty acid ester is preferably 20% by mass or more, more preferably 20 to 20% by mass, from the same point of view. It is preferably 80% by mass, more preferably 30 to 60% by mass.

The content of unsaturated fatty acids in the fatty acids constituting the polyglycerin fatty acid ester is preferably 80% by mass or less, more preferably 0 to 70% by mass, and further, from the viewpoint of interaction with raw material fatty acids and the melting point. It is more preferably 5 to 60% by mass, more preferably 10 to 50% by mass.

Two or more kinds of polyglycerin fatty acid esters may be used in combination.
The amount of the polyglycerin fatty acid ester added is preferably 0.001 to 5% by mass, more preferably 0.05 to 1% by mass, based on the raw material fatty acids, from the viewpoint of filterability.
The timing of addition and mixing of the polyglycerin fatty acid ester is before the start of crystal precipitation, that is, before the start of cooling. The polyglycerin fatty acid ester is preferably mixed and dissolved at a temperature higher than the melting point of the polyglycerin fatty acid ester so that it can be completely dissolved in the raw material fatty acids.

Then, the mixture is cooled with stirring at a peripheral speed of 1.0 to 3.0 m / s.
The peripheral speed of stirring is 1.0 to 3.0 m / s, but it is more preferably 1.05 m / s or more from the viewpoint of mixing in a huge commercial facility, and further, suppression of crystal crushing and suppression of crystal crushing and From the viewpoint of filterability, it is more preferably 2.8 m / s or less.
The stirring blade may have any shape, but is preferably a paddle blade, a turbine blade, a propeller blade, an anchor blade, a large blade diameter paddle blade, or a max blend blade in order to improve crystal mixing.

The cooling temperature of the raw material fatty acids may be any temperature as long as the saturated fatty acids crystallize and precipitate, but from the viewpoint of separation efficiency, it is preferably in the range of −10 to 10 ° C., and more preferably −8 to 8 ° C.

The average cooling rate calculated from the time required from the temperature at the time of adding and mixing the polyglycerin fatty acid ester to the cooling temperature is 1 to 10 ° C./min, and further 2 to 9 ° C. from the viewpoint of crystal growth and efficiency. It is preferable to have. The cooling rate may be varied during the cooling operation. The change in the cooling rate is preferably 1 to 4 times. In addition, the method of changing the change is to increase the cooling rate until the temperature at which the crystals do not precipitate, and to increase the cooling rate near the temperature at which the crystals precipitate, from the point that the efficiency and the crystal grow greatly and the filterability is improved. It is preferable to reduce it.

The cooling time varies depending on the amount of raw material fatty acids, cooling capacity, etc., and may be appropriately adjusted. Generally, the cooling time is 1 to 30 hours.

After cooling, the precipitated crystals and the liquid part are separated.
The method of solid-liquid separation is not particularly limited, and examples thereof include filtration, centrifugation, and sedimentation separation. By the separation, a saturated fatty acid is obtained as a solid part (crystal part), and an unsaturated fatty acid is obtained as a liquid part.

[Analysis method]
(I) Measurement of fatty acid composition Fatty acids according to "Methyl esterification method (boron trifluoride methanol method) (2.4.1.2-1996)" in "Standard Fatty Acid Analysis Test Method 2003" edited by Japan Oil Chemists' Society. Methyl esters were prepared and the obtained samples were subjected to gas chromatography for analysis of constituent fatty acids.

(Ii) Measurement of melting point Measurement was performed by the standard oil and fat analysis test method (2.2.4.1-1996).

(Iii) Measurement of acid value The acid value was measured according to "Acid value (23.1-1996)" in "Standard Oil and Fat Analysis Test Method 2003" edited by Japan Oil Chemists' Society.

(Iv) Measurement of free fatty acid concentration The free fatty acid concentration was determined by the following formula (2) by measuring the acid value and fatty acid composition of the raw material fatty acids. The average fatty acid molecular weight of flaxseed oil was 280.
Fatty acid concentration (mass%) = a × b / 56.11 / 10 (2)
(A = acid value [mgKOH / g], b = average molecular weight obtained from fatty acid composition)

[Preparation of raw material fatty acids]
Linseed oil was hydrolyzed with a hydrolase (lipase) to prepare the raw material fatty acids shown in Table 1. Table 1 shows the fatty acid composition, saturated fatty acid ratio, [(P) / (S)] ratio, and free fatty acid concentration of each raw material fatty acid.

[Polyglycerin fatty acid ester]
Table 2 shows the analytical values of the polyglycerin fatty acid ester used in the following examples. The average degree of polymerization of glycerin of PGE1 to 3 was 38.

<Example 1>
Using the crystallization tank (No. 1) shown in Table 3, 3 g of PGE2 was added to 2 kg of raw material fatty acids (raw material 1), and the mixture was uniformly dissolved at 70 ° C. Then, while stirring at a stirring blade peripheral speed of 1.05 m / s (stirring speed of 200 r / min), the mixture was cooled to 16 ° C. at 6 ° C./hr and from 16 ° C. to 6 ° C. at 2.25 ° C./hr for 5 hours. Stirring was maintained. Next, using a nylon filter cloth (filtration area 39 cm ² , NY1260NLK, manufactured by Mitsubishi Kakoki Co., Ltd.), pressure filtration was performed at 0.03 MPa to form a liquid part (unsaturated fatty acid) and a solid part (saturated fatty acid) as a filtrate. Sorted. The time required for the amount of the filtrate to reach 400 mL was measured and used as the filtration time (minutes). In addition, the concentration of saturated fatty acids having 12 to 22 carbon atoms in the liquid part was determined.

<Comparative Example 1>
The polyglycerin fatty acid ester to be added was separated into a liquid part (unsaturated fatty acid) and a solid part (saturated fatty acid) according to the method described in Example 1 except that the polyglycerin fatty acid ester was changed to PGE1. The time required for the amount of the filtrate to reach 400 mL was measured, and the concentration of saturated fatty acids having 12 to 22 carbon atoms in the liquid part was determined.

<Reference example 1>
The liquid part (unsaturated) was according to the method described in Example 1 except that the polyglycerin fatty acid ester to be added was changed to PGE1 and the peripheral speed of the stirring blade was changed to 0.79 m / s (stirring speed 150 r / min). It was separated into a fatty acid) and a solid part (saturated fatty acid). The time required for the amount of the filtrate to reach 400 mL was measured, and the concentration of saturated fatty acids having 12 to 22 carbon atoms in the liquid part was determined.

<Example 2>
Using the crystallization tank (No. 2) shown in Table 3, 4.2 kg of PGE2 was added to 2800 kg of raw material fatty acids (raw material 2), and the mixture was uniformly dissolved at 70 ° C. Next, while stirring at a stirring blade peripheral speed of 2.25 m / s (stirring speed 25 r / min), the mixture was cooled to 16 ° C. at 8 ° C./hr and from 16 ° C. to 6 ° C. at 3 ° C./hr, and stirred for 5 hours. Retained. Then, a filtration operation was carried out according to the method described in Example 1 to separate the liquid part (unsaturated fatty acid) and the solid part (saturated fatty acid). The time required for the amount of the filtrate to reach 400 mL was measured, and the concentration of saturated fatty acids having 12 to 22 carbon atoms in the liquid part was determined.

<Example 3>
Using the crystallization tank (No. 3) shown in Table 3, 13.3 kg of PGE3 was added to 8900 kg of raw material fatty acids (raw material 3), and the mixture was uniformly dissolved at 70 ° C. Then, while stirring at a stirring blade peripheral speed of 2.64 m / s (stirring speed 28r / min), the temperature is 6 ° C / hr up to 11 ° C, 2 ° C / hr from 11 ° C to 5 ° C, and 5 ° C to -3 ° C. The mixture was cooled to 3 ° C./hr and kept stirring for 4 hours. Next, a filtration operation was performed according to the method described in Example 1, and the liquid portion (unsaturated fatty acid) and the solid portion (saturated fatty acid) were separated. The time required for the amount of the filtrate to reach 400 mL was measured, and the concentration of saturated fatty acids having 12 to 22 carbon atoms in the liquid part was determined.
The results are shown in Table 4.

As is clear from the comparison between Comparative Example 1 and Reference Example 1 in Table 4, the filterability deteriorates when the stirring conditions become strict, but the [y / x] value is in a predetermined range as in Examples 1 to 3. It was confirmed that the raw material fatty acids can be efficiently and naturally separated with excellent filterability even under strong stirring conditions.

Claims (4)

Using a crystallization tank with an inner diameter of 0.13 m or more, polyglycerin fatty acid ester is added and mixed with the raw material fatty acids, and then cooled with an anchor blade at a peripheral speed of 1.0 to 3.0 m / s to cool the crystals. A method for producing a saturated fatty acid or an unsaturated fatty acid, which comprises a step of solid-liquid separation after precipitation.
The melting point of the polyglycerin fatty acid ester is 25 to 40 ° C., and the content mass ratio x of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acids constituting the polyglycerin fatty acid ester, and the raw material fatty acids. A production method, wherein the content mass ratio y of the saturated fatty acid having 16 carbon atoms to the saturated fatty acid having 18 carbon atoms in the fatty acid composition of the above satisfies the relationship of the following formula (1).
0.8 ≤ y / x ≤ 1.7 ... (1) The method for producing a saturated fatty acid or an unsaturated fatty acid according to claim 1, wherein the glycerin of the polyglycerin fatty acid ester has an average degree of polymerization of 15 to 50. The method for producing a saturated fatty acid or an unsaturated fatty acid according to claim 1 or 2, wherein the amount of the polyglycerin fatty acid ester added is 0.001 to 5% by mass with respect to the raw material fatty acids. The saturated fatty acid or unsaturated fatty acid according to any one of claims 1 to 3, wherein the raw material fatty acid is a fatty acid derived from at least one oil and fat selected from perilla oil, flaxseed oil, perilla oil, chia seed oil and sacha inchi oil. Method for producing fatty acid.