JP2664999B2 - Egg yolk phosvitin extraction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for extracting yolk phosvitin.

[Conventional technology]

Egg yolk phosvitin is about 2 of the proteins contained in egg yolk.
% Of the protein, which has a strong ability to chelate iron and copper ions and is a natural antioxidant. Further, since it easily binds to calcium ions, it is expected as an auxiliary agent for a calcium content enhancer.

However, conventionally, to extract phosvitin from egg yolk, as shown in J. Agric. Food Chem., Vol 25, No. 3 1977, 632-637, add fresh egg yolk in diluted saline and centrifuge. A precipitate (aggregate) consisting of a mixture of phosvitin and lipovitelin is obtained, and the aggregate is dissolved in 1N saline, and then a high-concentration aqueous solution of ammonium sulfate is added to the saline, and then tens of thousands of revolutions / minute (rpm) Centrifuge and precipitate (lipovitelin)
Except that phosvitin was collected from the resulting supernatant.

As described above, according to the conventional method, there is a problem that the obtained phosvitin is expensive because the extraction step of phosvitin is complicated. Further, the conventional method has a problem that only raw egg yolk can be used as a raw material of phosvitin, and therefore, defatted egg yolk insoluble in fresh water cannot be used as a raw material.

[Problems to be Solved by the Invention] By the way, today, when demand for phosvitin is expected, it is urgently necessary to supply phosvitin at low cost. Is desired.

Thus, the present inventors have conducted research for developing such a technique, and as a result, have completed the present invention.

[Means for solving the problem]

The present invention relates to a method for extracting yolk phosvitin, adding an aqueous solution of ammonium sulfate to yolk or defatted egg yolk and stirring, elutes phosvitin into this aqueous solution, removes aggregates from the aqueous solution,
Next, phosvitin is collected from the aqueous solution.

In the present invention, the yolk means, in addition to raw egg yolk obtained by breaking a shell egg to remove egg white, frozen yolk obtained by freezing raw yolk, yolk powder obtained by drying raw yolk, and the like. .
In addition, defatted egg yolk refers to those obtained by removing some or all of the oil and fat components such as lecithin and neutral lipids contained in the egg yolk with a solvent such as ethanol or hexane from the egg yolk, and is usually finished in a dry state. Commercially available as defatted egg yolk powder. Since defatted egg yolks have denatured egg yolk proteins due to solvent treatment and are insoluble in fresh water, they have been conventionally used only for feed for livestock and fry.

In the practice of the present invention, the raw yolk or defatted yolk is first facilitated. If the yolk is a frozen yolk, it may be thawed in advance. When the yolk is yolk powder or when the defatted yolk is dry, it may be used as it is.

Next, an aqueous solution of ammonium sulfate is added to the raw material and stirred to elute phosvitin contained in the raw material into the aqueous solution.
In order to efficiently elute phosvitin, when using dried egg yolk or defatted egg yolk, add a 70% saturated ammonium sulfate aqueous solution,
It is desirable to stir at 50 to 300 rpm for 3 to 24 hours. When using raw egg yolk, add a 100% saturated ammonium sulfate aqueous solution so that the final ammonium sulfate concentration becomes 70% saturated, and then add this aqueous solution to 80%.
It is desirable to heat the egg yolk protein for about 15 minutes at -100 ° C to coagulate the yolk protein.

Next, aggregates insoluble in the aqueous ammonium sulfate solution are removed from the aqueous ammonium sulfate solution from which phosvitin has been eluted. Aggregates can be removed by low-speed centrifugation or filtration.

Lastly, phosvitin is collected from the aqueous solution from which the aggregates have been removed. In order to collect phosvitin, for example, the aqueous solution is adjusted to pH 1.5 to 1.8 to precipitate phosvitin and separated from the aqueous solution, or the aqueous solution is dialyzed against dilute hydrochloric acid to precipitate phosvitin. There is a method of separating from an aqueous solution.

As described above, the method of extracting yolk phosvitin of the present invention comprises:
It consists of a combination of agitation, precipitation and separation steps, can be industrially performed using a large tank or a centrifuge, and can mass-produce egg yolk phosvitin. And although the yolk phosvitin thus obtained is extracted by an extremely simple process, it has a high purity (95%
Above).

〔Example〕

Example 1 A 70% saturated aqueous solution of ammonium sulfate 2 was added to 100 g of defatted egg yolk powder (trade name "York Protein H" manufactured by KP Corporation), followed by stirring at 200 rpm for 24 hours.

Next, this aqueous solution was centrifuged at 3,000 rpm for 15 minutes to remove aggregates, and then filtered with No. 5C filter paper.

Next, the obtained filtrate is passed through a dialysis tube (cut molecular weight of about
10,000), 5 to 6 ° C for about 20 times the volume of 0.04N hydrochloric acid
, And centrifuged at 3,000 rpm for 15 minutes. The obtained precipitate was washed with 0.04N hydrochloric acid, further dialyzed against distilled water, and freeze-dried to obtain 740 mg of egg yolk phosvitin.

Example 2 70 g of 100 g of defatted egg yolk powder (same as used in Example 1)
2% saturated ammonium sulfate aqueous solution 2 was added and stirred at 200 rpm for 24 hours.

Next, this aqueous solution was centrifuged at 3,000 rpm for 15 minutes to remove aggregates, and then filtered with No. 5C filter paper. Then, after adjusting the pH of the filtrate to 1.8 and aggregating phosvitin, 3,000
The precipitate was collected by centrifugation at rpm for 15 minutes, and the precipitate was dialyzed against distilled water and freeze-dried to obtain 664 mg of egg yolk phosvitin.

Example 3 Using 10 g of yolk powder (trade name "yolk powder", manufactured by KUP Co., Ltd.) as a raw material, the yolk powder was treated in the same manner as in Example 1 to obtain 106 mg of yolk phosvitin.

Example 4 Egg yolk powder as raw material (same as used in Example 3) 10
This yolk powder was treated in the same manner as in Example 2 to obtain 30 mg of yolk phosvitin.

Example 5 As raw material, 20 g of raw egg yolk obtained by breaking shelled eggs was used.
To this, add 40 ml of distilled water and 70 ml of a saturated aqueous solution of ammonium sulfate, and add
Heat for 5 minutes. Next, centrifugation was performed at 3,000 rpm for 15 minutes to remove the floating aggregates, thereby obtaining a lower layer liquid. This lower layer solution is
The solution was filtered through o.5C filter paper, and the filtrate was treated in the same manner as in Example 1 to obtain 93 mg of egg yolk phosvitin.

Example 6 Raw egg yolk as raw material (same as used in Example 5)
Using 20 g, a lower layer solution was obtained in the same manner as in Example 5. This lower layer solution was treated in the same manner as in Example 2 to obtain 27 mg of egg yolk phosvitin.

(Test example)

The yolk phosvitin obtained in Examples 1 to 6 was used as a test group, 83 g of raw egg yolk was added with an equal volume of 0.16N saline, and the mixture was centrifuged at 20,000 rpm for 30 minutes.
Disperse in 60 g 0.16 N saline, then add this suspension to
Centrifuge at 00 rpm for 30 minutes to obtain a precipitate,
After dissolving in 5 g of 1N saline, 226 g of 100
% Saturated ammonium sulfate aqueous solution,
Filtration was performed by centrifuging at 15 rpm for 15 minutes, and phosvitin was collected from this filtrate in the same manner as in Example 1 (known J. Agric
Food Chem), and the obtained egg yolk phosvitin was used as a control.

And the yield of each said yolk phosvitin was calculated and the purity was measured, and the result of Table 1 was obtained.

The yield is a percentage (weight ratio) of the obtained yolk phosvitin with respect to the theoretical value of the content of yolk phosvitin contained in the raw material. The purity was measured from the results of SDS polyacrylamide gel electrophoresis and the results of constrained liquid chromatography (using anion exchange chromatography).

[Effects of the Invention] As described above, according to the present invention, high-purity egg yolk phosvitin can be obtained with a high yield by a simple method. And since yolk phosvitin can be mass-produced using a large tank or a centrifuge, it is possible to provide yolk phosvitin at low cost. Also, there is an advantage that egg yolk phosvitin can be obtained using defatted egg yolk, which has not been used so far as a raw material.

Claims (1)

(57) [Claims] (1) An aqueous solution of ammonium sulfate is added to egg yolk or defatted egg yolk, stirred, phosvitin is eluted in the aqueous solution, aggregates are removed from the aqueous solution, and phosvitin is collected from the aqueous solution. Egg yolk phosvitin extraction method.