JPH0881692A - Production of oil and fat - Google Patents

Abstract

PURPOSE: To efficiently deacidify an oil and fat containing a free fatty acid by simple operations and obtain the oil and fat of good quality by dissolving an oil and fat containing a free fatty acid in a polar organic solvent and then mixing an aqueous solution of a specific salt with the resultant solution. CONSTITUTION: This method for producing an oil and fat is to dissolve an oil and fat containing a free fatty acid, preferably at 5-15% concentration in a polar organic solvent, then mix an aqueous solution of a carbonate or a phosphate with the resultant solution and usually separate the hydrous organic solvent containing the fatty acid and fat and oil by centrifugation. Furthermore, the concentration of the carbonate or the phosphate is preferably 0.1-0.3% and the ratio of the solution of the oil and fat in the polar organic solvent to the aqueous solution of the salts is preferably (10:5) to (10:12). When an edible oil and fat is produced, ethyl alcohol or acetone is preferably used as the polar organic solvent and sodium carbonate or disodium hydrogenphosphate is preferably used as the carbonate or phosphate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing fats and oils from fats and oils containing free fatty acids.

[0002]

2. Description of the Related Art Oils and fats used for food are all natural products derived from animals and plants. The fats and oils extracted as the natural products often contain free fatty acids. In many cases, a lipase reaction is used to hydrolyze fats or oils or fatty acids constituting fats and oils are subjected to transesterification reaction to be reformed into fats and oils having a novel function. Natural fats and oils contain free fatty acids even though their contents differ. The fat and oil treated with lipase contains a large amount of free fatty acids. The content of this free fatty acid, so-called acid value, represents the quality of fats and oils, and it is necessary to reduce the content of fatty acids in fats and oils to below a specified amount. For this purpose, a step of separating and removing natural fats and oils or fatty acids produced by enzymatic reaction from fats and oils is performed. This step is called a deoxidation step, but generally, an alkaline aqueous solution is directly added to oils and fats containing free fatty acids and stirred, and then fatty acids are removed as soap by centrifugation, or oils and fats containing free fatty acids are mixed with non-polar organic compounds such as hexane. Dissolve in a solvent, add a water-containing polar organic solvent such as alcohol or acetone to this, add and mix an alkali such as sodium hydroxide or potassium hydroxide, and centrifuge to collect the hexane layer from which free fatty acids have been removed. The so-called alkaline deoxidation method, such as the production of fats and oils by vacuum concentration, is generally performed.

[0003]

When the amount of fatty acid mixed in fats and oils is very small, after converting the fatty acid to sodium salt with an alkali such as sodium hydroxide or potassium hydroxide,
By the method of separating from fats and oils by means such as centrifugation, fats and oils having an acid value of not more than a specified amount can be produced, but since a strong alkali is used, the fats and oils should be sufficient so that the alkalis do not remain in the fats and oils. It was complicated to wash with water. Further, in the case of fats and oils having an extremely large acid value such as lipase-treated fats and oils, in the above-mentioned deoxidation method, the whole fatty acid is emulsified because it is dispersed in the fats and oils as soap, and the fats and fatty acids are also separated by centrifugation. Was extremely difficult to separate. In such a case, a fat or oil containing a free fatty acid is dissolved in a non-polar organic solvent such as n-hexane, an alkali such as sodium hydroxide or potassium hydroxide is added, and the free fatty acid is soaped from the hexane layer into a hydrous alcohol. Since the process of shifting to (1) was complicated, it was necessary to use many kinds of solvents. Even in this method deoxidation efficiency is insufficient,
There are problems such as coloring due to alkalis, conversion of fatty acids in fats and oils present in the form of esters into ethyl esters, and a complicated process of washing and removing remaining alkalis. An object of the present invention is to efficiently deoxidize fats and oils containing free fatty acids to produce high-quality fats and oils.

[0004]

Means for Solving the Problems As a result of earnest studies on a method for efficiently separating fats and oils from free fatty acids, the present inventors have dissolved fats and oils containing free fatty acids in a polar organic solvent, and then added carbonate Alternatively, they have found that oils and fats and fatty acids can be efficiently separated by a simple operation of adding an aqueous solution of phosphate, and have completed the present invention.

According to the present invention, in the step of removing free fatty acids from fats and oils containing free fatty acids, a solution of the fats and oils containing free fatty acids in a polar organic solvent is mixed with an aqueous solution of carbonate or phosphate to contain fatty acids. A method for producing fats and oils, characterized in that a water-containing organic solvent and fats and oils are separated.

The present invention will be described in more detail below. Although various alcohols and ketones can be used as the polar organic solvent that dissolves the fats and oils containing free fatty acids used in the present invention, ethyl alcohol and acetone are preferred for the production of edible fats and oils. The types of fats and oils containing free fatty acids include natural fats and oils derived from animals, plants and microorganisms,
It may be an oil or fat containing free fatty acids after hydrolysis or transesterification of these oils or fats with lipase. As the lipase, lipase derived from plants and animals and microorganisms is used. For example, there are lipases produced by pancreatic lipase, Chromobacterium, Pseudomonas, Penicillium, Rhizopus, or Candida.

The concentration of fats and oils containing free fatty acids is 1 to 3.
It can be used in the range of 0%, but is preferably 5 to 15%. When a divalent metal ion such as calcium chloride is added to the lipase reaction system to carry out an enzymatic reaction, fatty acids produced by the enzymatic reaction form calcium salts. When the oil or fat is extracted from the reaction product with acetone or ethyl alcohol, the calcium salt of this fatty acid is insoluble in these polar organic solvents, and therefore it is preferable to remove it by filtration or centrifugation in advance.

Next, an aqueous solution of carbonate or phosphate is added to the oil / fat solution obtained by the above operation, and mixed and stirred.
The concentration of carbonates and phosphates is 0.0, depending on the concentration of fats and oils.
It can be used in the range of 5 to 1%, preferably 0.
It is 1 to 0.3%. Carbonates having a deoxidizing effect include sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, and the like, and phosphates include disodium hydrogen phosphate, dipotassium hydrogen phosphate, ammonium dihydrogen phosphate, trisodium phosphate, and the like. Examples thereof include salts such as tripotassium phosphate. When the target oil and fat is edible oil and fat, sodium carbonate and disodium hydrogen phosphate are preferable. Moreover, these salts may be used alone or in combination. The ratio of the oil solution to the salt solution is 10: 1 to 1
It can be used in the range of 0:20, but is preferably 10: 5 to 10:12.

The mixing of the oil / fat solution and the aqueous salt solution may be carried out within a temperature range (0 to 50 ° C.) at which the target oil / fat does not solidify. Although temperature control may be performed, stirring and mixing may be performed at room temperature. When the sufficiently stirred mixture is subjected to centrifugation, the oil and fat can be separated into the upper layer and the fatty acid can be separated into the lower layer. Centrifugation may be performed in a batch format, but continuous centrifugation is preferred in the case of large-scale processing. Since the oil and fat component in the upper layer contains a small amount of a polar solvent, a fatty acid-free oil and fat can be obtained by removing it by an operation such as concentration under reduced pressure.

[0010]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to efficiently deoxidize fats and oils containing a large amount of free fatty acids.
It is possible to produce high-quality fats and oils.

[0011]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. (Example 1) 12 grams of 10 grams of olive oil having an acid value of 2.6
Dissolve in 0 ml of acetone and add 100 ml to this oil solution.
0.25% of an aqueous solution of carbonate and phosphate shown in Table 1 was added, and the mixture was stirred at room temperature for 2 hours. Then, this mixed solution was centrifuged at 3,000 rotations for 5 minutes. The upper oil and fat layer was recovered, and a small amount of acetone contained in the oil and fat was removed under reduced pressure to obtain an oil and fat. The results of measuring the acid value of the obtained fats and oils are shown in Table 1.

[0012]

[Table 1]

Example 2 500 ml of a reaction solution composed of 0.005 M Tris-hydrochloric acid buffer (pH 8.2), 0.2 M calcium chloride, and 5% gum arabic was added,
12,500 units (U) of lipase derived from Candida lipolytica was dissolved, and 50 g of fish oil (DHA content: 22.4%, EPA: 7.0%) was mixed,
The pH was adjusted to 8.2 at 25 ° C, and the hydrolysis reaction was performed for 15 hours with stirring (hydrolysis rate: 72%). The decomposed oil was collected by filtration, 750 ml of ethyl alcohol was added thereto, stirred at room temperature, and then centrifuged at 3,000 rpm for 10 minutes to obtain an extract. Then, the extract was mixed with 0.
After adding 750 ml of a 2% aqueous solution of disodium hydrogen phosphate and centrifuging (3,000 rpm, 10 minutes), the upper layers were collected and concentrated under reduced pressure to obtain 12.4 g of oil and fat. The ethyl alcohol extract had an acid value of 38.5, and the fat and oil after deoxidation had an acid value of 0.08.

(Comparative Example 1) 500 ml of a reaction solution composed of 0.005 M Tris-hydrochloric acid buffer (pH 8.2), 0.2 M calcium chloride, and 5% gum arabic,
12,500 units (U) of Candida lipolytica-derived lipase were dissolved, and 50 g of fish oil (DHA content: 22.4%, EPA: 7.0%) was mixed,
The pH was adjusted to 8.2 at 25 ° C, and the hydrolysis reaction was performed for 15 hours with stirring (hydrolysis rate: 72%). The decomposed oil was collected by filtration, 600 ml of acetone was added thereto, and the mixture was stirred at room temperature and then centrifuged at 3,000 rpm for 10 minutes to obtain an extract. Next, this extract was concentrated under reduced pressure to obtain 13.7 g of a solvent-free fat and oil containing free fatty acid (acid value: 36.3). 0.43 ml of 20% sodium hydroxide aqueous solution was added to this oil and fat while stirring. After stirring at room temperature for 1 hour, 3,000 rpm, 30
Centrifuge for minutes. After recovering the oil / fat layer, the oil / fat was washed with a sufficient amount of water to obtain 11.7 g of an oil / fat. The acid value of this fat was 1.8.

Claims (4)

[Claims] 1. In the step of removing free fatty acids from fats and oils containing free fatty acids, an aqueous solution of carbonate or phosphate is added to and mixed with a solution of fats and oils containing free fatty acids in a polar organic solvent, and a water-containing organic substance containing fatty acids is mixed. A method for producing fats and oils, characterized in that a solvent and fats and oils are separated. 2. The carbonate or phosphate is sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate,
The method for producing fats and oils according to claim 1, which is a salt of any of disodium hydrogen phosphate, dipotassium hydrogen phosphate, ammonium dihydrogen phosphate, trisodium phosphate, tripotassium phosphate, or a mixture thereof. 3. The method for producing fats and oils according to claim 1, wherein the polar organic solvent is ethyl alcohol or acetone. 4. The method for producing fats and oils according to claim 1, wherein the fats and oils containing free fatty acids are natural fats and oils treated with lipase.