JPS62263192A - Production of egg yolk lecithin - Google Patents

Abstract

PURPOSE:To sanitarily obtain high-purity lecithin in high yield, by extracting lipid in egg yolk with a specific mixed solvent, adding ice, fractionating and removing a water-soluble layer and treating the residual solvent layer with an ultrafiltration membrane. CONSTITUTION:A mixed solvent of an alcohol, e.g. ethanol, etc., and a nonpolar solvent, e.g. n-hexane, etc., preferably at 50/50-10/90 ratio of the alcohol to the nonpolar solvent in a volume of 1-5 times based on lecithin is added thereto and then stirred to carry out solid-liquid separation. The solvent extracting lipid containing the lecithin is recovered. Water in an amount of preferably 0.05-0.3pts.wt. based on the nonpolar solvent in the above-mentioned solvent is added to separate and remove the alcohol and the nonpolar solvent layer is passed through a solvent-resistant ultrafiltration membrane having >=5,000 fractionation molecular weight to fractionate the lecithin into a neutral lipid fraction and afford the aimed high-purity lecithin.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for extracting and producing lecithin from egg yolk. In particular, the present invention relates to a method for hygienically obtaining high-yield lecithin of high purity that can be used in pharmaceuticals and the like.

Lecithin is used in the food and pharmaceutical fields due to its surface activity, and egg yolk lecithin is used and developed in the pharmaceutical field, including artificial blood, lipo-emulsions, and vitamin E, due to its emulsification retention and safety. Therefore, establishing a method for producing egg yolk lecithin that is inexpensive and highly safe will greatly contribute to these industries.

``Prior art'' There are several known methods for producing egg yolk lecithin.
7-6259 and the like. Tokuko Sho 56-4791
Method 5 is a method for separating lecithin and neutral lipids by extracting and separating lecithin, neutral lipids, and some water from raw egg yolk with dimethyl ether, removing the solvent, and adjusting the water content in the extracted oil.

In this method, lecithin is recovered together with water, so it must be dehydrated and dried afterwards, but it is not possible to raise the temperature of the product because it affects the quality of the lecithin, forcing expensive freeze-drying. It has drawbacks such as:

Japanese Patent Publication No. 46-42186 involves adding half to twice the amount of monohydric alcohol and a small amount of acid to egg yolk, stirring to bring the pH to about 3 to 6, and then adding twice to four times the amount of water to the egg yolk and centrifuging to remove the upper layer. It is characterized by separating the triglyceride/sterin layer, which does not contain phospholipids, into a phospholipid layer and a protein layer. This process denatures protein with acid or alcohol, making it easier to separate lipids and proteins.As is known from degumming (removal of phospholipid content) from vegetable oils, phospholipids are removed in the presence of water. Taking advantage of the fact that it does not dissolve in neutral lipids such as triglycerides,
Water is added to separate it from triglycerides, and it is further separated from proteins based on the difference in specific gravity.

Japanese Patent Publication No. 37-6259 discloses a method for obtaining extracted egg yolk oil by soaking and filtering egg yolks which have been semi-dried to a moisture content of 37 to 29% with acid-added absolute alcohols, and then using an oil-fat solvent. This method requires pretreatment steps such as semi-drying and acid removal.

The steps such as filtration are complicated, and the obtained egg yolk oil contains neutral lipids, unlike the high-purity lecithin expected by the present inventors.

Lecithin is normally insoluble in acetone, but neutral lipids are soluble in acetone, so lecithin,
Methods for purifying methane are also known, but these methods have the disadvantage that deacetonization is not easy and mesityl oxide, which has a characteristic odor, remains.

As described above, the methods known so far are high in cost, have complicated steps, and contain components with unique odors, so there is still room for improvement.

"Problems to be Solved by the Invention" The purpose of the present invention is to extract lipids containing lecithin from egg yolks and to produce lecithin from the lipids using safe solvents commonly used in food production. The object of the present invention is to provide a method capable of obtaining hygienically safe and highly purified lecithin at a high yield.

Egg yolk is approximately 50% water, 15% protein, and 35% fat.
It is a system in which neutral lipids are emulsified with lecithin, cholesterol, and protein. Since this emulsion is very stable, even if an extraction operation is performed simply with a non-polar solvent such as hexane, the extraction rate is very low, and in particular, phospholipids, which are polar lipids, are difficult to extract.

The present inventors focused on the fact that emulsification is an effect of lecithin, cholesterol, and protein, and preferably denatured the protein by freezing, etc., and then used a mixed solvent of alcohols and non-polar solvents to create an emulsified system. The present inventors have discovered a method for producing lecithin at a high yield by destroying it and efficiently extracting lipids, and then separating lecithin and neutral oil from this extraction process into fecal matter, thereby completing the present invention.

"Means for Solving the Problems" That is, the present invention extracts lipids in egg yolk with a mixed solvent consisting of alcohols and non-polar solvents, adds water to the mixed solvent layer, and extracts the water-alcohol layer. This is a method for producing egg yolk lecithin, which is characterized in that lecithin is obtained by treatment with an ultrafiltration membrane.

The present invention will be explained in detail below.

In the present invention, when extracting and manufacturing lecithin from egg yolk, first, a mixed solvent consisting of alcohols and a non-polar solvent is added to the egg yolk, and after stirring, solid-liquid separation is performed to recover the solvent from which lipids containing lecithin are extracted. .

In this case, the extraction can be carried out efficiently by denaturing the egg yolk protein in advance, preferably by freezing the egg yolk.

When egg yolks are used industrially, they are often frozen for hygiene and storage reasons, but in this case, salts such as table salt, sugar, etc.*i are added to reduce protein denaturation. used.

In the present invention, we have discovered that by freezing egg yolks as they are, proteins are actively denatured and the subsequent extraction rate is increased. If freezing is sanitary, there is no need to flash freeze the food, and it is sufficient to store it at the temperature at which it is normally shipped frozen.

As the alcohol used in the present invention, methanol, ethanol, propatool, etc. can be used, but from the viewpoint of food hygiene, it is preferable to use ethanol.As the non-polar solvent, benzene, hexane, etc. can be used. , n-, which is still used for edible oil extraction, etc.
Preferably hexane is used. The amount of mixed solvent used is preferably 1 to 5 times the volume of egg yolk in terms of extraction efficiency.

The mixing ratio of alcohols and non-polar solvents in the mixed solvent used in the present invention is in the order of alcohol/non-polar solvent-5015
0 to 10/90 is preferable, more preferably 25/75 to
It is 15/85. As shown in Table 1, when the ratio of alcohols increases, the phospholipid content in the extracted lipids increases, but the total lipid extraction rate decreases, which is undesirable. At the same time, the phospholipid content also becomes low, which is undesirable.From these results, the above mixing ratio is preferable.

Table 1 Extraction rate Note: Add 2000 mjl of solvent to 1000 g of frozen egg yolk, stir at room temperature using a homomixer, centrifuge, and analyze the lipid content in the solvent layer obtained. Lecithin, neutral lipids, etc. are extracted, but alcohols must be removed during the ultrafiltration process in the next step. By adding 0.5 parts of water, preferably 0.05 to 0.3 parts of water, the alcohols are separated off from the non-polar solvent together with the water.

The alcohol aqueous layer and the nonpolar solvent layer thus separated can be easily separated using decanethisilane or the like.

During this process, lecithin was slightly dissolved in the polar solvent, but if the amount of water added was within the above range, the amount was negligible and could be ignored in industrial production.

As a result of an investigation of adding salts to the water, it was found that by using monovalent metal salts such as sodium chloride and potassium chloride, the distribution of lecithin to the aqueous layer was further reduced and the yield was improved. However, when divalent metal salts such as calcium and magnesium were used, they reacted with lecithin to form insoluble matter, resulting in a low yield.

Thereafter, the resulting non-polar solvent layer is passed through a solvent-resistant ultrafiltration membrane to fractionate the lecithin component into a neutral lipid fraction to obtain highly pure lecithin.

The ultrafiltration membrane should have a molecular weight fraction of 15,000 or more that can separate lecithin aggregates and neutral lipids, and constant volume filtration and batch filtration may be repeated using the same non-polar solvent to increase purity. can.

Examples of such ultrafiltration membranes include DOS-40 (cylindrical module, membrane material: polyethersulfone, molecular weight cutoff: 40,000) manufactured by Daicel Chemical Industries, Ltd., and PM-10, 30, 50 manufactured by Romicon. and 100 hollow fiber module, membrane material: polysulfone, molecular weight cut off: 5000.10000, 30000.50000 and 100000, respectively), IRIS- manufactured by Mitsui Petrochemical Corporation ■
3038 (flat plate module, membrane material: polyacrylonitrile copolymer, molecular weight cutoff: 15,000-2,000
0 and MPS-3400 (flat plate model, membrane material: polysulfone, fractionated molecules 11: 30,000-40
000).

"Example" Example 1 A mixed solvent of 1000 ml of hexane and 1000 ml of ethanol was added to 1000 g of frozen egg yolk, stirred for 5 minutes using a homomixer, and then centrifuged at 3000 rpm for 5 minutes to obtain 11,820 m/ml of a solvent. Water 3 in this solvent layer
After adding 00 ml of the mixture and allowing it to stand still, decantation was performed to obtain 980 ml of hexane iJ. The lipid content in the hexane layer was 25.8%. This ultrafiltration membrane D [1S-40 (molecular weight cut off 40) manufactured by Daicel Chemical Industries, Ltd.
000) and hexane 3000mA! Volumetric filtration was performed using a filtration solution to obtain 82 g of egg yolk lecithin with a purity of 90%.

Example 2 1000 g of frozen egg yolk and 1600 ml of hexane! ,
Ethanol 400mm! After adding a mixed solvent and stirring for 5 minutes using a homomixer, centrifugation was performed at 3000 rpm for 5 minutes to obtain a solvent layer containing 1 ton of solvent and 1960 ml of solvent. After adding 200mj of 3% saline solution to the solvent layer and leaving it to stand,
Perform decantation to obtain a hexane layer of 1620 m I
I got l. The lipid content in hexane was 20.8%.

This is an ultrafiltration membrane manufactured by Mitsui Petrochemical Industries, Ltd., MPS-3.
400 (molecular weight cut off 30,000-40,000)
Volumetric filtration was performed using 0ml to obtain 108g of 95% pure egg yolk lecithin.

"Effects of the Invention" As is clear from the above, according to the present invention, high-purity egg yolk lecithin that can be used in pharmaceuticals can be produced simply, in high yield, and hygienically and safely. Lecithin has a very good flavor, unlike that obtained by fractionation with acetone, and is used in cosmetics, cosmetics, etc.
It has high utility value as an emulsifier and surfactant in foods, etc.

Claims (10)

[Claims] (1) Extract the lipids in the egg yolk with a mixed solvent consisting of alcohols and non-polar solvents, add water to the mixed solvent layer,
A method for producing egg yolk lecithin, which comprises separating a water-alcohol layer and treating the obtained non-polar solvent layer with an ultrafiltration membrane to obtain lecithin. (2) The manufacturing method according to claim 1, wherein the alcohol is ethanol. (3) The manufacturing method according to claim 1, wherein the nonpolar solvent is n-hexane. (4) The manufacturing method according to claim 1, wherein extraction is performed with a mixed solvent of 1 to 5 times the volume of egg yolk. (5) The mixing ratio of alcohol and non-polar solvent in the mixed solvent is alcohol/non-polar solvent = 50/50 to 10/90
The manufacturing method according to claim 1. (6) The production according to claim 1, wherein the amount of water added to the solvent phase obtained by solid-liquid separation is in the range of 0.01 to 0.5 times based on 1 part of the non-polar solvent used. Method. (7) The manufacturing method according to claim 1, wherein the aqueous phase added to the solvent phase contains a monovalent metal salt. (8) The manufacturing method according to claim 7, wherein the monovalent metal salt is sodium chloride. (9) The manufacturing method according to claim 1, wherein the solvent-resistant ultrafiltration membrane has a molecular weight cutoff of 5,000 or more. (10) The manufacturing method according to claim 1, wherein the egg yolk is frozen egg yolk.