JPH0725797B2 - Twain manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing highly etal-soluble zein from corn or corn gluten meal.

[Conventional technology]

Zein, which is the main component of corn protein, is soluble in alcohol, has adhesiveness and the ability to form films and fibers, and can be sprayed with alcohol or alkaline solutions.
It is known that a film excellent in water resistance, acid resistance, heat resistance, electric insulation, etc. is formed by adhering it to the surface of the object to be treated by an appropriate means such as coating or dipping and drying it. .

Due to these properties, zein is used as a coating agent for papermaking, surface coating of wood products, an adhesive agent for plywood, a moistureproof agent, and a coating agent for foods, tablets and the like.

Regarding the manufacturing method of zein, JP-A-61-167700 and “Seed Proteins Biochemistry, Genetics, Nutritive Value (Seed Prote
ins Bichemistry, Genetics, Nutritive Value) "(W.Go
ttschalk, HP Muller, Martinus Nijhoff / Dr.W.Junk
Publishers, 1983) 70-90% of raw materials such as corn gluten meal are generally used as outlined on pages 275-287.
(V / v) Ethal, 90% (v / v) About 90% (v / v) Isopropal and other hydrous lower alcohols are extracted, and the solvent is distilled off from the resulting alcohol solution, or the solution is poured into water or a salt solution. Then, it is produced by a method such as precipitating zein.

[Problems to be solved by the invention]

In applications such as coating materials for foods and tablets, zein is most importantly required to be soluble in ethanol, that is, dissolved in various concentrations of etal and stable for a certain period of time. However, the conventional method for producing zein has the first purpose of increasing the recovery rate of zein from the raw materials, and no etal-soluble products have been satisfactory so far. In other words, the standard of zein is 20 times the amount of 6
When observed by dispersing and dissolving in 0,80 and 90% (v / v) of each etal solution, the product produced by the conventional method appears to be well dispersed, but the precipitates appear when left for a day. etc,
All had poor solubility. For use as a drug coating, depending on the application, it is desired that the alcohol solution be kept completely clear for at least one day and night.

[Means for solving problems]

The present invention provides a method for maintaining a high level of recovery of zein from a raw material and obtaining zein having extremely good solubility in etal.

The present invention is a method for producing zein in which zein is extracted and separated from corn or corn gluten meal using hydrous ethanol, and the zein is extracted while maintaining the pH of the extract at 8 to 10. Is the law. In addition, the extract according to the above is concentrated to a solid concentration of 20 to 50%, and this is added to water to separate precipitated zein,
When recovered, a product with particularly good odor and color tone is obtained.

Corn gluten meal, which is one of the starting materials of the present invention, is obtained as a by-product in the process of separating and producing corn starch from corn by a conventional wet treatment method. 80 if using corn as the starting material
It is recommended to pulverize to 100 mesh or less before use.

In the present invention, first, 60 to 90% (v /
Extract with the hydrous etal of v). The extraction step is
Using the water-containing etal in an amount equivalent to 3 to 10 times that of the raw material,
It is carried out at 65 ° C. for 30 to 180 minutes with stirring, but it is essential to maintain the pH of the extract at 8 to 10 throughout the whole extraction process. For example, when gluten meal is extracted with 5 times the volume of 90% (v / v) hydrous ethanol at 60 ° C for 2 hours, the pH of the extract is from the initial 6.4 to 5.2, and the initial extract is water. Even if the pH is adjusted to 8 with an alkaline agent such as sodium oxide, it will also drop to about 5.2.

In the present invention, a method such as operating a pH stat device equipped with an automatic pH measuring mechanism and an alkaline agent automatic adding mechanism that works in conjunction with the method is appropriately applied to continuously maintain the pH of the extract at 8-10. It is a thing. When the pH of the extract is lowered to 8 or less, the solubility of zein prepared from it in etal is remarkably lowered, and further, the yield of zein with respect to the raw materials is lowered. Further, even if the pH of the extract is increased to 10 or higher, the extraction rate hardly increases, which may cause an undesirable decomposition reaction of zein, which is disadvantageous.

After extraction for a predetermined time, an extract is obtained by an appropriate means such as centrifugation or pressure filtration.

From the extract obtained as described above, zein is recovered by a known method such as removing etal by distillation, concentrating it if necessary, and then dropping it into water or a neutral salt solution to precipitate zein. can do.

As a means of recovering zein, the above-mentioned extract was added to the solids concentration 20
It is especially advantageous if it is concentrated to about 50% and the precipitate formed by adding this to water (approximately 6 times the amount of the concentrated solution or more) is obtained because high-quality zein with little odor or coloration can be obtained. is there. In order to obtain zein with little odor and coloration by this method, the pH of the extract is adjusted to 8 ~
It is necessary to maintain the temperature at 10, and it is not possible to obtain such high-quality zein from an extract obtained by another method.

〔Example〕

Example 1 500 g of 90% (v / v) hydrous ethanol in 100 g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation and concentrated,
By drying, zein having a protein purity of 88.2% is obtained with a yield of 24.8% (W) (% of raw material).

Example 2 500 ml of 90% (v / v) hydrous ethanol in 100 g of gluten meal
Was added for 2 hours at 60 ° C., and the pH of this extract was adjusted to 9.0-9.5 throughout the entire extraction period by intermittently adding 1N sodium hydroxide using a pH stat device. After the passage of time, an extract was obtained by centrifugation, concentrated and dried to give 24.7% (W) of zein with a protein purity of 88.1%.
Obtained in a yield of (% of raw material).

Example 3 100 ml of gluten meal 500 ml of ethanol containing 80% (v / v)
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
It was adjusted to be in the range of 8.0 to 8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation and concentrated,
By drying, zein having a protein purity of 87.2% is obtained in a yield of 27.2% (W) (% of raw material).

Example 4 500 ml of 70% (v / v) hydrous ethanol in 100 g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation and concentrated,
By drying, zein having a protein purity of 87.3% is obtained with a yield of 27.3% (W) (% of raw material).

Example 5 Gluten meal 100 g, 60% (v / v) hydrous ethanol 500 ml
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation and concentrated,
By drying, zein having a protein purity of 87.2% is obtained with a yield of 29.2% (W) (% of raw material).

Example 6 500g of 90% (v / v) hydrous ethanol in 100g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation,
Concentrate and shrink to 20%. This concentrate was added dropwise to 10 times the amount of cold water to precipitate zein, which was recovered by centrifugation and dried in vacuum to give 15.7% zein with a protein purity of 97.8%.
Obtained in a yield of (W) (% of raw material).

Example 7 Gluten meal 100 g, 90% (v / v) hydrous ethanol 500 ml
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
It was adjusted to be in the range of 9.0 to 9.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation,
Concentrate to 20%. This concentrated solution was added dropwise to 10 times the amount of cold water to precipitate zein, and zein having a protein purity of 98.2% was obtained by centrifugation at a yield of 16.3% (W) (% of raw material).

Example 8 500 ml of 80% (v / v) hydrous ethanol in 100 g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation,
Concentrate to 20%. This concentrate was added dropwise to 10 times the amount of cold water to precipitate zein, which was recovered by centrifugation and dried in vacuum to give 17.1% zein with 96.8% protein purity.
Obtained in a yield of (W) (% of raw material).

Example 9 Gluten meal 100 g, 70% (v / v) hydrous ethanol 500 m
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation,
Concentrate to 20%. This concentrated solution was dropped into 10 times the amount of cold water to precipitate zein, and zein having a protein purity of 97.2% was obtained by centrifugation at a yield of 18.2% (W) (% of raw material).

Example 10 500 g of water containing 60% (v / v) water in 100 g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device,
Adjusted to be in the range of 8.0-8.5 throughout the extraction period. After a lapse of time, an extract was obtained by centrifugation,
Concentrate to 20%. This concentrate was added dropwise to 10 times the amount of cold water to precipitate the zein, which was recovered by centrifugation and vacuum dried to yield 19.5% zein with a protein purity of 96.5%.
Obtained in a yield of (W) (% of raw material).

The zein obtained by the production method of the present invention has extremely excellent alcohol solubility, maintains a stable clear state even when left standing for a long time, and does not cause coloring or odor.

Next, a test example for clarifying this will be shown.

Test Example 1. Test sample Zein obtained by the manufacturing method of the present invention of Examples 1 to 10,
As a control, the zein obtained in the following production example was used.

Production Example 1 500g of 90% (v / v) hydrous ethanol in 100g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is 6.
It decreased from 4 to 5.2 at the end of extraction. After a lapse of time, an extract was obtained by centrifugation, concentrated and dried to a protein purity of 87%.
Get the zein of.

Production Example 2 Using the same raw material as in Production Example 1, extraction was performed at 60 ° C. for 2 hours.
The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device and adjusted to be in the range of 7.0 to 7.5 throughout the period to obtain zein with a protein purity of 87.5%.

Production Example 3 The same raw material as in Production Example 1 was used, extraction was performed with 80% (v / v) hydrous ethanol, and the pH of the extract was adjusted throughout the entire extraction period.
A zein having a protein purity of 87.0% is obtained by the same procedure as in Production Example 2 except that the zein is adjusted to a range of 0 to 7.5.

Production Example 4 The same raw material as in Production Example 1 was used, extraction was performed with 70% (v / v) hydrous ethanol, and the pH of the extract was adjusted throughout the entire extraction period.
A zein having a protein purity of 86.8% is obtained by the same procedure as in Production Example 2 except that the zein is adjusted to a range of 0 to 7.5.

Production Example 5 The same raw material as in Production Example 1 was used, extraction was carried out with 60% (v / v) hydrous ethanol, and the pH of the extract was adjusted throughout the entire extraction period.
A zein having a protein purity of 86.9% is obtained by the same procedure as in Production Example 2 except that the zein is adjusted to have a range of 0 to 7.5.

Production Example 6 500 ml of 90% (v / v) hydrous ethanol in 100 g of gluten meal
Was added and the mixture was extracted at 60 ° C. for 2 hours. The pH of the extract is 6.
It decreased from 4 to 5.2 at the end of extraction. After a lapse of time, an extract is obtained by centrifugation and concentrated to a solid content of 20%. The concentrate is added dropwise to 10 times the amount of cold water to precipitate the zein, and dried in vacuum to obtain zein with a protein purity of 91.3%.

Production Example 7 Using the same raw material as in Production Example 6, extraction was performed at 60 ° C. for 2 hours.
The pH of the extract is intermittently added with 1N sodium hydroxide using a pH stat device and adjusted so as to be in the range of 7.0 to 7.5 throughout the extraction period to obtain zein having a protein purity of 92.1%.

Production Example 8 The same raw material as in Production Example 6 was used, extraction was performed with 80% (v / v) hydrous ethanol, and the pH of the extract was adjusted to 7.0 to 7.5 throughout the entire extraction period according to Production Example 7. Zein with a protein purity of 91.6% is obtained.

Production Example 9 The same raw material as in Production Example 6 was used, extraction was performed with 70% (v / v) hydrous ethanol, and the pH of the extract was adjusted throughout the entire extraction period.
A zein having a protein purity of 90.3% is obtained by the same procedure as in Production Example 7, except that the zein is adjusted to have a range of 0 to 7.5.

2. Test method 1 g of each sample above is 20% volume 60% (v / v), 80% (v / v),
It was dispersed and dissolved in 90% (v / v) water-containing ethanol, and the state immediately after that and after 24 hours at 25 ° C was observed.

In addition, zein obtained in Examples 6 to 10 and Production Examples 6 to 9
The zein obtained in 1. was also observed for color and odor.

3. Test results The test results are shown in the table below.

As is clear from Table 1, in the case where zein was extracted according to the present invention while maintaining the pH of the extract at 8 to 10, the concentration of the extracted etal was in the range of 60 to 90% (v / v). , 60,
It showed excellent solubility for all tested concentrations of etal at 80 and 90% (v / v), making it suitable for applications such as drug coating. On the other hand, in those without pH adjustment and with extraction at pH 8 or less,
All of them had poor solubility and were not suitable for the above purpose.

As is clear from Table 2, zein extracted according to the present invention while maintaining the pH of the extract at 8 to 10 has excellent solubility in hydrous ethanol as in the previous section, and also has no dye or pigment during precipitation with water. Since impurities such as odor components are dissolved and removed in water, it is possible to obtain high-quality zein having a light hue and a small odor. On the other hand, in the case where the pH was not adjusted and the case where the extraction was performed at a pH of 8 or less, not only the solubility but also the removal of the pigment and the odorous component were poor.

〔The invention's effect〕

According to the present invention, it is possible to economically produce zein, which is suitable as a coating agent for medicines, foods, etc., has particularly high solubility in etal, and has no coloration or odor. Of course, the zein according to the present invention can be used as an industrial material, a confectionery material, etc., and has a wide range of applications.

Claims (2)

[Claims] 1. A method for producing zein in which zein is extracted and separated from corn or corn gluten meal using hydrous ethanol, wherein the zein is extracted while maintaining the pH of the extract at 8 to 10. Manufacturing method. 2. An extract obtained by extraction from corn or corn gluten meal with hydrous ethanol while maintaining the pH of the extract at 8 to 10 is concentrated to a solid concentration of 20 to 50%. The method for producing zein according to claim 1, wherein the zein precipitated in addition to water is separated and recovered.