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JP-7856808-B2 - Composition containing highly unsaturated fatty acids or their alkyl esters and method for producing the same

JP7856808B2JP 7856808 B2JP7856808 B2JP 7856808B2JP-7856808-B2

Inventors

  • 土居崎 信滋
  • 降旗 清代美
  • 山口 秀明

Assignees

  • 株式会社ニッスイ

Dates

Publication Date
20260511
Application Date
20250228
Priority Date
20181212

Claims (7)

  1. A composition comprising a fatty acid or a fatty acid alkyl ester as a main component, wherein the composition contains a highly unsaturated fatty acid or its alkyl ester, the proportion of highly unsaturated fatty acids in the constituent fatty acids of the composition is 50 area% or more, the concentration of 3-MCPD obtained when the composition is analyzed by the American Oil Chemists' Society official method Cd29b-13 assay A is less than 1.80 ppm, and (1) the concentration of the trans isomer of the highly unsaturated fatty acid alkyl ester is 0.01 area% or more, or (2) the cholesterol content is 0.01 by weight or more.
  2. The composition according to claim 1, wherein the proportion of highly unsaturated fatty acids in the constituent fatty acids of the composition is 70 area % or more.
  3. The composition according to claim 1 or 2, wherein the concentration of 3-MCPD obtained when the composition is analyzed by the American Oil Chemists' Society official method Cd29b-13 assay A is below the detection limit.
  4. The composition according to claim 1 or 2, wherein the concentration of 3-MCPD obtained when the composition is analyzed by the American Oil Chemists' Society official method Cd29b-13 assay A is 0.01 ppm or higher.
  5. The composition according to any one of claims 1 to 4, wherein the highly unsaturated fatty acid is eicosapentaenoic acid, docosahexaenoic acid, dihomo-γ-linolenic acid, arachidonic acid, or a combination thereof.
  6. A composition according to any one of claims 1 to 5, which is a distillate.
  7. A composition according to any one of claims 1 to 6, wherein the raw material is fish oil, microbial oil, vegetable oil, or marine animal oil.

Description

This invention relates to a composition containing a highly unsaturated fatty acid or its alkyl ester, and a method for producing the same. 3-Chloropropane-1,2-diol (3-MCPD) is a compound suspected of being carcinogenic. Regulations have been established in various countries, including the EU, regarding the concentration of 3-MCPD in food products. In oils and fats, it is known that 3-MCPD can be produced using diacylglycerol (DAG) and monoacylglycerol (MAG) as substrates (Non-Patent Document 1). Since the presence of 3-MCPD in oils and fats rich in diacylglycerol (DAG) was pointed out, various methods have been attempted to reduce its content in oils and fats. For example, it is known that 3-MCPD is formed at high temperatures, and Patent Documents 1 and 2 disclose that the concentration of substances that produce 3-MCPD in oils and fats can be reduced by adsorbent treatment, lowering the deodorization temperature, or shortening the treatment time. However, these are methods for reducing the concentration of substances that produce 3-MCPD in the production of triacylglycerol, and Patent Documents 1 and 2 do not describe methods for reducing the concentration of 3-MCPD fatty acid esters in the production of alkyl esters. Polyunsaturated fatty acids (PUFAs) are known to possess various functional properties, and highly concentrated PUFAs are used in foods, supplements, pharmaceuticals, and cosmetics. When PUFAs are highly concentrated, increasing the proportion of the desired PUFA in the starting composition, they are converted from glycerides, primarily triacylglycerols, to alkyl esters with lower alcohols. Therefore, highly purified and concentrated PUFAs used in foods, supplements, pharmaceuticals, and cosmetics are often alkyl esters. To date, no method has been known to reduce the concentration of 3-MCPD fatty acid esters in such high-concentration PUFA alkyl esters. Factors known to influence the formation of 3-MCPD fatty acid esters include the chlorine source, substrates such as MAG and DAG, and processing time at high temperatures (Non-Patent Documents 1 and 2). However, in oils used as raw materials for foods containing PUFAs, the content of chlorine sources and substrates such as MAG and DAG is usually small, and their impact on the purification of the target PUFA is extremely small. Therefore, the need to remove them is not generally recognized. Furthermore, complete removal of chlorine sources and substrates such as MAG and DAG is not performed due to the technical difficulty and its impact on productivity, such as the recovery rate of PUFAs. Rectification is a type of distillation that offers high separation capabilities, but it often requires heating at high temperatures of 150°C or above because it necessitates internal packing and reflux. Molecular distillation and short-path distillation are different. Although the heating temperature is below 150°C, and the process can be carried out at a relatively low temperature compared to rectification, repeated processing is required to sufficiently concentrate PUFAs. Therefore, there is a risk of generating a large amount of 3-MCPD during PUFA distillation. Urea addition and HPLC are methods for separating molecules based on the structure of the fatty acids that make up the molecule (e.g., chain length, number of double bonds, etc.). However, when 3-MCPD is present in the raw material as a di or mono fatty acid ester, it can be difficult to separate it from the target alkyl ester depending on the type of fatty acid that makes up the ester, making it difficult to stably obtain a fatty acid alkyl ester with reduced 3-MCPD fatty acid ester levels. Therefore, purification processes involving heat treatment such as solvent removal and distillation carry a clear risk of generating 3-MCPD fatty acid esters, and methods such as urea addition and HPLC do not necessarily remove the diverse 3-MCPD fatty acid esters present in the raw materials. Japanese Patent Publication No. 2011-147435Japanese Patent Publication No. 2011-147436 Eur. J. Lipid Sci. Technol. 114, 1268-1273 (2012)Eur. J. Lipid Sci. Technol. 115, 735-739 (2013)J. Agric. Food. Chem. 63(6) 1839-48 (2015) The present invention will be described in detail below. In this specification, when describing fatty acids, numerical representations using a combination of numbers and letters may be used to express the number of carbon atoms, the number of double bonds, and the position of the double bonds in a simplified manner. For example, a saturated fatty acid with 20 carbon atoms may be written as "C20:0", a monounsaturated fatty acid with 18 carbon atoms as "C18:1", and eicosapentaenoic acid as "C20:5 n-3", etc. "n-" indicates the position of the double bond counted from the methyl end of the fatty acid. For example, "n-3" indicates that the bond between the third and fourth carbon atoms counted from the methyl end of the fatty acid is a double bond. This method is well known to those skilled in the art,