JPS5967241A - Method for concentrating eicosapentaenoic acid in fish oil - Google Patents

Abstract

PURPOSE:To concentrate eicosapentaenoic acid in a fish oil, containing the eicosapentaenoic acid in high concentration, and useful as an edible fat or oil, by treating the fish oil containing the eicosapentaenoic acid as a fatty acid component with acetone under specific temperature conditions. CONSTITUTION:A fish oil containing eicosapentaenoic acid (hereinafter abbreviated to EPA), having inhibitory action on agglutination of blood platelets, and known to have the activity of about 4 times of the linoleic acid used as a preventing agent for cardiovascular diseases, e.g. cerebral thrombosis or cardiac infraction or a cholesterol-lowering agent capable of reducing cholesterol in the blood as a fatty acid component is introduced into acetone in a volume of 2-15 times of the EPA cooled at <=-25 deg.C, preferably at -40--60 deg.C, and kept at the above-mentioned temperature for 1-5hr under stirring. The acetone is then separated and distilled away to concentrate the EPA in the fish oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for concentrating EPA in fish oil to obtain an edible fat containing eicosapentaenoic acid (hereinafter abbreviated as EPAj) at a high concentration.

KPA has the effect of inhibiting platelet aggregation, and research by Dr. Dyerberg of Denmark (Am.
, J-Cl1n, Nat,, 28.58 Sada.

(1975) and research by Dr. Bain et al. (Lance
t.

2, p. 117, 1978).

It is also known that EPA not only inhibits platelet aggregation but also lowers blood cholesterol (6), and its activity is about four times that of linoleic acid, which is currently being used as a cholesterol-reducing agent. It is being

Since its potential as a medicine or health food was shown, consumption of sardines, mackerel, saury, etc., which contain a large amount of EPA'aj, has been advocated. However, the amount of fish oil contained in these fish is about 6% of their body weight, and the EPA content in the fish oil is about 8 to 17%. Therefore, a relatively large sardine with a weight of 100 g should contain about 6 g of fish oil, but when this is actually grilled in a fish roaster, most of the oil falls out. The amount of oil remaining in the edible portion is reduced to about 1.5g on average, or about 230rv in terms of EPA. On the other hand, it is said that the recommended intake of EPA for adult males is 2 to 3g per day, so eating grilled sardines and EPA'! & To add light, eat 8 or more fish every day.
In other words, it is necessary to eat three or more fish at every meal, and it can be said that it is impossible to do this without any knowledge. Therefore, it is desirable to extract oil from these fish in a fresh state and then extract only the part containing a high degree of EPA and use it as a concentrated fish oil for use as a raw material for medical products, foods, or food additives.

However, in the case of sardine oil, for example, it is in the form of a mixed glyceride containing saturated and unsaturated fatty acids with 12 to 24 carbon atoms and more than 70 fatty acids, and 1 to 3 fatty acids are bonded to one molecule of glyceride. There are monoglycerides 9, diglycerides 9, and triglycerides, and at the same time, there are many components such as isomers and optical isomers due to differences in the bonding position to the hydroxyl group of 3IvA of glycerin. Based on the physical and chemical properties of 9.1. No definitive method has yet been found to select the desired glycerinase, combine them, and condense them in the form of EPA'&1-IJ diglyceride.

All EPAs have 20 carbon atoms and 5 double bonds in the cis form.
Because it is a straight-chain highly unsaturated fatty acid, it is an unstable fatty acid that is extremely easily oxidized, and when concentrating EPA from fish oil, it is necessary to completely isolate it from heat buildup and heat. .

The present inventors have been conducting research for many years on a method for concentrating and separating fish oil while allocating the characteristics of EPA, but the molecular distillation method described above has the possibility of thermal denaturation, and the liquid chromatography method requires a Due to the fact that solvents are regulated by the Tribute Collection Law, the amount of solvent used is large, and the collection equipment is too large, the solvent extraction method becomes very hot. As a result of conducting research, it was found that when the fish oil contained in EPA' is cooled, solidified to an excessive size, and extracted with acetone at a low temperature, EPA's glycerides are more easily eluted into bare acetone than other glycerides, and are particularly difficult to extract. Temperature is below 125°C, preferably between -30 and -
It was found that this tendency becomes greater at 70°C.

When the fish oil itself is cooled, it changes slightly depending on its composition, but
The composition of the eluted fish oil may differ slightly from that of the raw fish oil depending on the type of organic solvent and the contact temperature when the fish oil is brought into contact with the solvent. When acetone is used as a solvent, the proportion of EPA glyceride in the eluted fish oil is greater than that of other solvents, and the lower the contact temperature, the greater the proportion. For example, at temperatures higher than -25°C, the proportion of EPA glycerides in fish oil eluted into acetone increases by only a few percent compared to that of the raw fish oil, but at temperatures below -25°C, it increases by as much as 10-16%. However, if the temperature is too low, the overall success in bathing will be reduced, so the more preferable temperature is -40 to -60°C.

According to the method of the present invention, fish oil containing EPA as a fatty acid component is poured into 2 to 15 times the volume of acetone cooled to -25°C or lower, and stirred for 2 to 44 hours to remove EPA in acetone.
Elute the fish oil at a rate of 1. In this case, the raw fish oil is put into acetone either at room temperature or after being cooled to an appropriate temperature in advance, and the fish oil is assimilated in the acetone. At this time, to prevent the fish oil from forming large lumps, it is preferable to add the fish oil to the cooled acetone in small portions (preferably, add the fish oil dropwise while stirring. After dropping -25
After stirring for 1 to 5 hours while maintaining the temperature below ℃, it is separated. When acetone is distilled off from the liquid part, EPA Miyamae dog fish oil is obtained. When the amount of acetone used is small, the composition of the eluted fish oil is the same as that of the raw fish oil, and as the amount of acetone is increased, the proportion of EPA in the eluted fish oil increases, but when the amount of acetone is excessive, the composition approaches that of the raw fish oil. The amount of acetone used is preferably 2 to 15 times the amount.

Furthermore, in the method of the present invention, the chemical used is acetone, which has extremely low toxicity and is approved by the Food Sanitation Law as an extraction solvent for edible oils and fats, and does not require other e-alkali or chromatographic carriers. . Furthermore, since the process is carried out at an extremely low temperature of -25° C. or lower, the fish oil does not undergo deterioration such as rancidity, oxidation, or polymerization (this is also a favorable condition from the perspective of preserving the freshness of the fish oil).

There is no example of obtaining a fish oil with a high EPA content by extracting a fish oil with a clear EPA content with acetone as in the present invention (the present invention is a method that can only be realized at a temperature of -25°C or lower).

The present invention will now be described in detail with reference to its implementation.

Example 1 Fish caught off the coast of Boso in May 1973, average length 20-2
33kt of sardine oil was extracted from 500q of fresh Inuba sardines, 4cm long and weighing 105.9cm, using the pre-preparation method in a nitrogen stream. Regarding the quality of this fish oil, the color tone is number 3 according to the 9 Gardner method established by the Japan Oil Chemists' Association, and the peroxide value is 2.1.
It is. Methanol was added to a portion of the mixture and heated in the presence of sodium methylate to convert the total fat v into methyl ester through a transesterification reaction, and then the fatty acid composition was analyzed using gas chromatography.
The content was 17.5%.

This sardine oil was pulverized with an atomizer while being cooled with liquid nitrogen, and then 500 g of the oil was added to acetone 4 cooled to -40'C and extracted with stirring for 5 hours. After suction filtration at -40°C, acetone was distilled off from the extract to obtain 115 g of extracted fish oil.

The color tone of this fish oil according to the Gardner method was No. 4, and the peroxide value was 3.2. According to the fatty acid composition analysis results by gas chromatography, the concentration of EPA is 29
．． It was 0%.

Example 2 From 500kJL of fresh saury with a body length of 27 to 30cm and an average weight of 130g, 30k was harvested in a nitrogen stream using the pre-preparation method.
I obtained saury oil.

This fish oil had a color tone of number 3 according to the Gardner method and a peroxide value of 3.3. The EPA content according to the same analytical method as in Example 1 was 10.3%.

The mixture was added dropwise to 250 g of the saury oil and acetone cooled to -50°C with stirring, stirred at -50°C for 3 hours, and then filtered to obtain an extract. Acetone Y was distilled off under reduced pressure at 50°C to obtain 43 g of shrunken fish oil.

The concentration of EPA according to gas chromatography method is 2
It was 5.3%. The color tone of the Gardner method is number 4,
The peroxide value was 3.6.

Claims (1)

[Claims] (1) Fish oil containing eicosapentaene as a fatty acid component is poured into acetone cooled to -25°C or below, and kept at that temperature with stirring for 1 to 5 hours, then the acetone portion is separated and the acetone is distilled off. Eicosa in fish oil is characterized by the introduction of citric acid.