JP2008239658A - Method for producing oil and fat with reduced free fatty acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing an oil and fat from which a free fatty acid is reduced and which has a good color from an oil and fat composition containing the free fatty acid by a simple operation in high recovery. <P>SOLUTION: The method for producing the oil and fat with the reduced free fatty acid includes mixing (A) the oil and fat containing the free fatty acid, with (B) an alkali agent, (C) an organic solvent and (D) water, and passing the resultant mixed liquid through a hydrophobic nonporous membrane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing fats and oils from which free fatty acids have been removed from a fat and oil composition containing free fatty acids.

  When producing fats and oils useful for food, an operation for removing excess free fatty acids coexisting in the fat and oil composition is performed. For example, when selectively hydrolyzing only saturated fatty acids from fats and oils and removing them out of the system, or when producing fats and oils by reacting fatty acids with glycerin, excess excess fatty acids added are reacted. For example, when it is removed later. In this case, the method of removing by distillation is common, but in order to reduce the amount of free fatty acids to the edible level, treatment at a high temperature is necessary. It may cause quality degradation such as an increase in saturated fatty acids.

Various methods of separation using membranes (hereinafter also referred to as “membrane separation methods”) have been proposed as methods for purifying oils and fats having a small thermal history. Phospholipids and wax content can be removed by treatment with an ultrafiltration membrane made of a general inorganic fine membrane (see Patent Document 1). As a method for removing free fatty acids by a membrane separation method, a method in which a solvent such as ethanol is added to an oil and fat composition containing free fatty acids and a solution in which only free fatty acids are dissolved is passed through a hydrophilic ultrafiltration membrane. Has been proposed (see Non-Patent Document 1). It has also been reported that waste edible oil can be decolorized by using a hydrophobic high density non-porous membrane as a waste edible oil regeneration technique using membrane separation (see Non-Patent Documents 2 and 3). .
Japanese Patent Laid-Open No. 4-132796 Oil Chemistry Vol.43, No.2, p.116 (1994) Oreoscience Vol.6, No.10, 484 (2006) Journal of the American Oil Chemistry Society Vol. 77, No. 3, p. 323 (2000)

  Among the above-mentioned conventional techniques, in the treatment with an ultrafiltration membrane comprising an inorganic fine membrane, free fatty acids cannot be removed, and a method by dissolving free fatty acids and permeating through a hydrophilic ultrafiltration membrane Then, it was found that the operation is complicated and the effect of improving the hue is small. Furthermore, in the method using a hydrophobic high-density non-porous membrane, removal of free fatty acids is not sufficient simply by permeation of fats and oils. Hue and free fatty acids are reduced unless an adsorption method using silica gel or the like is combined. It has also been found that this balance cannot be achieved.

  That is, the present invention provides a method for efficiently producing fats and oils containing free fatty acids from a fatty acid composition containing free fatty acids and having a good hue with a simple operation. Objective.

  Therefore, as a result of studying a method for removing free fatty acids, pigment components and the like from an oil and fat composition containing free fatty acids, the present inventor mixed an alkaline agent, an organic solvent, and water with the oil and fat composition to obtain a hydrophobic property. The inventors have found that by allowing permeation through a non-porous membrane, reduction of free fatty acids and improvement of hue can be achieved simultaneously, and the present invention has been completed.

  That is, the present invention mixes (A) an oil and fat composition containing a free fatty acid, (B) an alkali agent, (C) an organic solvent and (D) water, and then permeates the mixed solution through a hydrophobic non-porous membrane. The present invention provides a method for producing fats and oils with reduced free fatty acids.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture efficiently the fats and oils from which the free fatty acid is reduced and the hue is favorable from a fat and oil composition containing a free fatty acid by a simple operation with a high recovery rate.

  As the fat and oil composition containing free fatty acids used in the present invention, crude oil obtained by squeezing or extracting a fat raw material, or crude purification obtained by subjecting the crude oil or fat to a treatment such as filtration or centrifugation Examples of the fats and oils include oils and fat compositions obtained by esterification reaction of fatty acids and glycerin, and fats and oils obtained by subjecting raw material fats and oils to high-pressure hydrolysis, enzyme hydrolysis, alkali treatment, heat treatment, and the like. These oil and fat compositions may contain triglycerides, diglycerides, monoglycerides and other trace components in addition to free fatty acids.

  The oil and fat composition containing the free fatty acid used in the present invention is derived from vegetable oils such as rapeseed, sunflower, corn, soybean, sweet potato, rice, safflower, and cottonseed, and animals such as cows, pigs, and fish. An oil and fat raw material can be mentioned. According to the method of the present invention, since the operation at high temperature is not performed, the obtained fats and oils hardly increase in trans unsaturated fatty acids. Therefore, in the constituent fatty acids, the fats and oils composition having a high unsaturated fatty acid content is obtained. It is preferable to apply to this. It is preferable to use an oil or fat composition having an unsaturated fatty acid content in the constituent fatty acid in the oil or fat composition of 10% by mass (hereinafter simply referred to as “%”) or more, further 40 to 100%, particularly 70 to 90%. preferable. Specifically, it is preferable to use a hydrolyzate of fish oil as the fat composition containing free fatty acids.

  The content of free fatty acid in the oil or fat composition containing free fatty acid used in the method of the present invention is preferably 1 to 80%. The method of the present invention exerts a higher effect on those having a high free fatty acid content in the oil and fat composition from the viewpoint that free fatty acids can be efficiently removed at a high recovery rate by a simple operation. The free fatty acid content in the oil / fat composition is further 2 to 80%, more preferably 5 to 75%, more preferably 10 to 75%, particularly 20 to 70%, and particularly 50 to 65%. From the viewpoint that free fatty acids can be efficiently separated.

  As the alkali agent of the component (B) used in the present invention, alkali metal or alkaline earth metal hydroxides and carbonates can be used. Specifically, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium hydrogen carbonate, or the like can be used, but alkali metal or alkaline earth metal hydroxides are preferable, among which sodium hydroxide, Use of calcium hydroxide is preferred from the viewpoint of solid-liquid separation efficiency (filtration rate) and oil / fat separability (glyceride recovery rate), and calcium hydroxide is particularly preferred. The amount of the alkaline agent used depends on the amount of free fatty acid contained in the oil and fat composition, but it is 1 to 10 moles, more preferably 1.5 to 5 moles, especially 1.7 to It is preferable to set it as 3 mol times from the point of solid-liquid separation efficiency and fat-and-oil separation property like the above.

  Examples of the organic solvent of component (C) used in the present invention include lower alcohols such as methyl alcohol and ethyl alcohol, acetone, ethyl acetate, chloroform, and hexane. Ethanol and acetone that can be used in food production processes Of these, hexane is preferable, and ethanol and acetone are particularly preferable from the viewpoint of solid-liquid separation efficiency and oil / fat separability. The amount of the organic solvent used is 5 to 97% in the mixed solution of (A) to (D), more preferably 40 to 90%, and particularly 50 to 80%, improving the removal rate of free fatty acids. It is preferable from the point which can improve the solid-liquid separation efficiency.

  The water of component (D) used in the present invention is ordinary water, and it is preferable to use purified water. (C) The amount of water used is such that the content in the mixture of (A) to (D) is 0.01 to 99.99%, more preferably 1 to 50%, especially 3 to 10%. It is preferable from the point which can improve the recovery rate of the fat and oil composition after removing the fatty acid removal rate and free fatty acid.

  In this invention, the mixing method of component (A)-(D) prepares the preparation liquid (E) containing component (B)-(D) previously, and component (A) free fatty acid is added to this. It is preferable from the point of the removal efficiency of a free fatty acid to mix the fats and oils composition to contain. In addition, the preparation means of the preparation liquid (E) is not particularly limited, but it is an oil or fat prepared by mixing a liquid containing (B) an alkali agent and (D) water and (C) an organic solvent. It is preferable in terms of separability and removal efficiency of free fatty acids.

  In the present invention, the mass ratio of (C) organic solvent / (D) water is preferably 2 to 100, more preferably 4 to 50, particularly 5 to 25, and especially 6 to 20 It is preferable from the viewpoint that the removal efficiency of fatty acids and the recovery rate of fats and oils after removing free fatty acids can be improved.

In the method of the present invention, the conditions for mixing the components (A) to (D) are not particularly limited as long as the whole can be uniformly dispersed, but the stirring conditions at the time of mixing are 0.1 to 5 kW / It is preferable to carry out with a stirring power of m ³ and 0.2 to ³ kW / m ^{3 from} the viewpoint of sufficiently producing a salt of free fatty acid to improve the oil recovery rate and reducing the cost. The mixing temperature is preferably 0 to 50 ° C, more preferably 10 to 40 ° C, and particularly preferably 20 to 35 ° C.

  When the preparation liquid (E) is prepared in advance and mixed with the oil and fat composition containing (A) a free fatty acid, the mixing means of (A) and (E) is not particularly limited, but (E) ( It is preferable to add A), and in particular, it is preferable to gradually add (A) to (E) and further add dropwise. The time taken for the addition is preferably about 0.2 to 20 minutes, more preferably about 0.5 to 5 minutes. That is, for example, when 1 kg of (A) is processed, the addition rate is preferably 0.05 to 5 kg- (A) / min, and more preferably 0.2 to 2 kg- (A) / min. (E) is 100 to 800 parts by mass, more preferably 200 to 600 parts by mass, and particularly 300 to 500 parts by mass with respect to 100 parts by mass of (A). It is preferable from the point which can improve the collection | recovery rate of an oil-fat composition. The mixing temperature of (A) and (E) is preferably 0 to 50 ° C, more preferably 10 to 40 ° C, and particularly preferably 20 to 35 ° C.

In the method of the present invention, (A) an oil / fat composition containing free fatty acid, (B) an alkali agent, (C) an organic solvent, and (C) water are mixed, and then permeated through a hydrophobic non-porous membrane. Let
The hydrophobic nonporous membrane used in the method of the present invention is a composite membrane having a high density nonporous active layer on a support. The support has a role of maintaining the mechanical strength of the membrane, and the active layer actually acts on the separation of substances. The mechanism for separating the target object by the non-porous film is different from the porous film in that the difference in the degree of dissolution and diffusion of the target object with respect to the film is dominant. The hydrophobic non-porous membrane is preferably a membrane in the region of reverse osmosis membrane (RO) to nanofiltration membrane (NF), which is smaller than the ultrafiltration membrane (UF), according to the classification of the separation membrane by the molecular weight cut-off. The molecular weight cutoff is preferably in the range of several tens to several hundreds. As for the hydrophobicity of the membrane, the contact angle of water with the membrane is preferably 60 to 180 degrees, and particularly preferably 90 to 160 degrees. Examples of the membrane include a flat membrane, a spiral type, a tubular type, and a capillary type. Among these, a flat membrane and a spiral type are preferable from the viewpoint of operability. The thickness of the membrane is preferably 10 μm to 10 mm for the support and 0.01 to 10 μm for the active layer.

  The structure of the hydrophobic non-porous membrane includes, as an active layer, inorganic materials such as polymers such as polyimide, polyamide, polyethylene, polypropylene, polystyrene, polysulfone, polyvinyl, and polytetrafluoroethylene, and ceramics. Examples thereof include silicone resin, silicone rubber, phenol resin, cellulose acetate, aromatic polyamide, polyimide, chitosan gel, and zeolite. Among these, it is preferable to use a polyimide as a support and a composite film having a silicone resin as an active layer from the viewpoint of obtaining a high recovery rate of fats and oils with reduced free fatty acids and good hue. Specific examples of the hydrophobic non-porous film include NTGS-2200 (manufactured by Nitto Denko).

The method of allowing the mixed liquid of the components (A) to (D) to permeate the hydrophobic non-porous membrane is preferably a method by pressurization. The pressure is preferably 0.1 MPa or more, more preferably 0.5 MPa or more, particularly 1 MPa or more from the viewpoint of increasing the permeation rate, and 100 MPa or less, more preferably 50 MPa or less, particularly 10 MPa from the point of pressure resistance of the apparatus and avoiding filtration leakage. The following is preferred.
The temperature at which the mixed liquid of the components (A) to (D) is allowed to permeate through the hydrophobic non-porous membrane is −10 to 150 ° C., more preferably 0 to 80 ° C. from the viewpoint of the removal efficiency of free fatty acid and the permeation rate. 20-40 degreeC is preferable.

  According to the method of the present invention, the free fatty acid can be efficiently removed from the oil / fat composition containing the free fatty acid by non-heat treatment, so that the obtained oil / fat has a low content of trans-unsaturated fatty acid. Therefore, the fats and oils obtained by the present invention are particularly preferable as edible fats and oils.

[Preparation of oil and fat composition containing free fatty acid]
Tuna oil (Nippon Chemical Feed Co., Ltd.) was hydrolyzed with lipase-AY (Amanoenzyme Co., Ltd.), then centrifuged, and the oil phase was separated to obtain a fat composition containing free fatty acids as raw materials. . Table 1 shows the glyceride composition (%) and the fatty acid composition (%) of the raw oil composition. The fatty acid content was 55% and the hue was 10R + Y = 194.

[Various measurement methods for oil and fat composition]
The glyceride composition of the oil and fat composition was analyzed by liquid chromatography, and the fatty acid composition was analyzed by gas chromatography. The hue was measured by a method (133.4 mm cell) according to “Standard Analysis Method for Oils and Fats” (2.2.1.1-1996) established by the Japan Oil Chemists' Society. The Red value is R, the Yellow value is Y, and the hue is a value obtained by adding Y to a value obtained by multiplying R by 10 (10R + Y).

[Measurement method of fatty acid content of fat after membrane treatment]
The free fatty acid content of fat after membrane treatment is the soap content (expressed in mg / kg as sodium oleate) measured in accordance with the Japan Oil Chemists'Society's “Standard Oil Analysis Test Method” (2.6.2-1996) ) From the following formula (1).
FA (%) = C × 10 ⁻⁴ × M ₂ / M ₁ (1)
(FA: free fatty acid content, C: soap content, M ₁ : molecular weight of sodium oleate, M ₂ : average molecular weight of constituent fatty acids of fats and oils)

[Oil collection rate]
The recovery rate of fats and oils was calculated | required as a percentage of the mass of the fats and oils after film | membrane processing with respect to mass other than the free fatty acid in the fats and oils composition containing (A) free fatty acid.

Example 1
Water (5 g) and calcium hydroxide (6.5 g) were added to a 300 mL round bottom flask and weakly stirred. Further, 75 g of acetone was added and stirred uniformly at 400 r / min to prepare a preparation solution. 20 g of the prepared raw oil / fat composition was added dropwise at a rate of 20 g / min to the preparation solution with a liquid temperature of 20 ° C. while stirring, and the mixture was continuously stirred for 20 minutes after the addition.
The obtained liquid mixture was charged into a pressure filter C40-B (Nitto Denko Corporation), and a pressure of 2 MPa was applied with nitrogen while stirring to permeate the membrane. As the membrane, NTGS-2200 (Nitto Denko Corporation, a composite membrane having polyimide as a support and silicone resin as an active layer), which is a hydrophobic non-porous membrane, was used.
Acetone was removed from the obtained permeate using an evaporator at 50 ° C. and a reduced pressure of 5 to 30 kPa. Table 2 shows the recovery rate, hue, and free fatty acid content of the obtained fat.

Example 2
To a 300 mL round bottom flask, 20 g of water and 5.7 g of calcium hydroxide were added and stirred gently. Furthermore, 45 g of ethanol was added and stirred uniformly at 400 r / min to prepare a preparation solution. 20 g of the raw material oil composition prepared as described above was added dropwise at a rate of 20 g / min to the preparation solution with a liquid temperature of 20 ° C. while stirring, and the mixture was continuously stirred for 20 minutes after the addition.
The obtained mixed liquid was charged into a pressure filter C40-B (Nitto Denko Corporation), and the membrane was permeated by applying a pressure of 2 MPa with nitrogen while stirring. NTGS-2200 (Nitto Denko Corporation), which is a hydrophobic non-porous membrane, was used as the membrane.
Ethanol was removed from the resulting permeate using an evaporator at 50 ° C. and a reduced pressure of 5 to 30 kPa. Table 2 shows the recovery rate, hue, and fatty acid content of the resulting oil and fat.

Comparative Example 1
The same mixed solution as in Example 1 was used, and the membrane was No. 1 which is a high purity filter paper. The same operation as Example 1 was performed except having changed to 5C (ADVANTEC). Table 2 shows the recovery rate, hue, and fatty acid content of the obtained fat.

Comparative Example 2
The same operation as in Example 1 was performed, except that the same mixed solution as in Example 1 was used and the membrane was changed to MPF-50 (Nippon Abcor Corporation), which is a hydrophobic porous membrane. Table 2 shows the recovery rate, hue, and fatty acid content of the obtained fat.

As is apparent from Table 2, the fatty acid composition containing a free fatty acid is mixed with an alkali agent, an organic solvent and water and permeated through a hydrophobic non-porous membrane, whereby the free fatty acid is reduced and the hue is reduced. It was found that good fats and oils can be efficiently produced with a high recovery rate.
On the other hand, when filter paper (Comparative Example 1) or a hydrophobic porous membrane (Comparative Example 2) was used as the membrane, it was found that free fatty acids were not sufficiently reduced and the hue was poor.

Claims (4)

  (A) Oil composition containing free fatty acid, (B) Alkaline agent, (C) Organic solvent and (D) Water is mixed, and then the mixed liquid is allowed to permeate the hydrophobic non-porous membrane. Free fatty acid is reduced Method for producing oils and fats.   (A) The manufacturing method of the fats and oils of Claim 1 whose free fatty acid content in the fats and oils composition containing a free fatty acid is 1-80 mass%.   2. A preparation liquid (E) containing (B) an alkali agent, (C) an organic solvent and (D) water in advance, and (A) an oil and fat composition containing a free fatty acid is mixed with the preparation liquid (E). Or the manufacturing method of fats and oils of 2.   The preparation liquid (E) is prepared by mixing a liquid containing (B) an alkali agent and (D) water and (C) an organic solvent. The manufacturing method of fats and oils as described in any one of.