JP3362203B2 - Production method of functional protein material - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a functional protein material. More specifically, the present invention relates to a method for producing a functional protein material soluble in an organic solvent.

[0002]

2. Description of the Related Art Conventionally, it has been attempted to add a protein to synthetic fibers in order to improve the feel of the synthetic fibers, the inhalation and release of moisture, the heat retention and the like.

For example, Japanese Patent Application Laid-Open No. 1-293143 proposes that fine powder of gelatin and silk is dispersed in a synthetic resin. However, there are variations in the particle size of the fine powder, and the fine powder is Since it is not uniformly dispersed in the resin, the synthetic fiber produced from the synthetic resin is not satisfactory in terms of touch, balance between inhalation and release of moisture, and heat retention. Moreover, the fine pulverization of gelatin and silk has a problem that the handling is very difficult due to the complexity of the pulverization operation and the scattering of pulverized products.

Therefore, in order to improve the dispersibility of the protein in the resin, it is obvious that preferable results can be obtained if the protein can be dissolved in an organic solvent that dissolves the resin.

As a protein that can be dissolved in an organic solvent, for example, a simple protein, prolamin, is known, but it is only soluble in 60 to 90% ethanol (that is, an aqueous organic solvent). Since it is insoluble in ethanol and other organic solvents having a higher purity of not less than%, it cannot be put to practical use.

Further, Japanese Patent Application Laid-Open No. 52-25800 discloses that
A statement that a modified protein obtained by hydrolyzing an addition reaction product of a protein and an isocyanate compound in the presence of an organic solvent or an aqueous organic solvent is soluble in an organic solvent such as dimethyl sulfoxide (DMSO) and dimethylacetamide (DMA). Has been done. However, such a protein has an infrared absorption of 1
It functions as a protein because it is a so-called low molecular weight protein denatured product in which the side chains having an amide bond or a urethane bond at around 740 cm ^-1 and 1222 cm ^-1 are cleaved and only the side chains having a urea bond remain. May decrease.
Moreover, the solubility of such a modified protein in an organic solvent is not sufficient.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies in view of the above-mentioned state of the art, and as a result, one raw material protein was crosslinked with a specific crosslinking agent such as diisocyanate to form a polymer. Found that a protein material soluble in an organic solvent was obtained, and applied for a patent first (Japanese Patent Application No. 4-
53466).

The protein material provided by the invention according to the above application has practically sufficient solubility in an organic solvent, but if the solubility can be further increased or the material is provided with a function other than the solubility in an organic solvent. If possible, it is expected that the practical range will be greatly expanded.

[0009]

Means for Solving the Problems As a result of continuous research on organic solvent-soluble protein materials, the present inventor used two or more different proteins as raw material proteins in combination, and made them into a crosslinked polymer by the above method. It was found that the function of the obtained organic solvent-soluble protein material (for example, solubility in an organic solvent or adsorptivity described later) can be improved or the yield of the material can be increased, and the present invention is completed here. Came to do.

That is, in the present invention, at least two kinds of proteins, water and a cross-linking agent are mixed and cross-linked, and at least one kind selected from an alkylating agent, a Schiff's agent and an acid is added to the cross-linked product of the obtained protein. The present invention relates to a method for producing a functional protein material characterized by reacting.

In producing the functional protein material of the present invention (hereinafter referred to as "the material"), first, two or more kinds of proteins, water and a crosslinking agent are mixed (preferably vigorously mixed).
Thereby, the protein and the crosslinking agent are subjected to addition polymerization to obtain a crosslinked product of the protein. At this time, the protein and water may be mixed in advance to prepare an aqueous protein solution, and the crosslinking agent may be added thereto. Alternatively, the cross-linking agent may be dissolved in an organic solvent, and this solution may be mixed with protein and water. At that time, the liquid after mixing is separated into an aqueous phase and an oil phase, and most of the cross-linked protein is contained in the aqueous phase.

The protein used in the present invention is not particularly limited, but among them, proteins and peptides having a free amino group are preferable, and examples thereof include egg white protein of eggs such as chicken, quail, duck and goose, whey protein, serum. Examples thereof include proteins (serum albumin and the like), casein, gelatin and the like, and at least two kinds may be selected from these. The amount of the protein used (the total amount of the two or more proteins used) is not particularly limited and can be appropriately selected from a wide range, but it is preferable to use the protein so that the protein concentration is usually about 1 to 5% by weight. When two or more proteins are used in combination, the combined ratio of these proteins is not particularly limited and may be appropriately selected depending on the function of the material to be obtained, the purpose of use, and the like. For example, egg white and gelatin are used. When used together to obtain a material having excellent substance adsorption as described below, gelatin is usually used in an amount of 1 to 1 of the total amount (total amount of protein used).
About 30% by weight, preferably about 5 to 15% by weight may be used.

The cross-linking agent that reacts with proteins can react with free amino groups and alcoholic hydroxyl groups between proteins to cross-link the proteins by chemical bonds such as urea bond, urethane bond and acid amide bond. There is no particular limitation as long as it can control the hydrophobicity of the protein, and examples thereof include diisocyanate compounds, dialdehyde compounds and diketone compounds. Among them, the diisocyanate compound is highly reactive and can be preferably used. As the diisocyanate compound, conventionally known compounds can be widely used, and examples thereof include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPD).
I), naphthalene diisocyanate (NDI) and the like can be exemplified by compounds having two or more isocyanate groups in one molecule. The amount of the cross-linking agent used is not particularly limited, but usually the total number of moles of amino groups and alcoholic hydroxyl groups is calculated from the primary structure of the protein to be reacted, and the amount of cross-linking agent used (the number of moles) is determined accordingly. Good.

As the organic solvent used for dissolving the cross-linking agent in the organic solvent, well-known organic solvents which allow the interfacial addition polymerization of the protein and the cross-linking agent can be widely used, and examples thereof include chloroform, hexane and toluene. be able to.

The reaction between the protein and the crosslinking agent is usually carried out by mixing the protein, water and the crosslinking agent. The condition of this reaction is not particularly limited as long as it causes crosslinking between proteins, but it is usually carried out at room temperature for about 1 hour or more.

The cross-linked product of the protein produced by the above reaction may be isolated from the reaction mixture by the usual separation and purification means and used in the next reaction, or the reaction mixture containing the cross-linked protein may be directly subjected to the next reaction. You may use it.

Next, the material of the present invention is produced by reacting a crosslinked product of protein with at least one selected from an alkylating agent, a Schiffing agent and an acid.

First, the case of adding an alkylating agent will be described. It is presumed that the addition of the alkylating agent alkylates (modifies) the residual amino groups, phenolic hydroxyl groups and carboxyl groups in the protein cross-linked product to obtain the desired material as a gel. A wide variety of known alkylating agents can be used, and examples thereof include dialkyl sulfates such as dimethyl sulfate, alkyl sulfates, alkyl halides and alkyl sulfonates. still,
The use of dialkylsulfuric acid, alkylsulfate and the like has not only an effect as an alkylating agent but also an effect as a pH adjusting agent. The addition amount of the alkylating agent may be appropriately selected according to the degree of the above crosslinking reaction, etc., but it is usually assumed that all amino groups are crosslinked, and the phenolic hydroxyl group and the carboxyl group are extracted from the primary structure of the protein to be reacted. The total number of moles of the crosslinking agent may be calculated, and the amount of the crosslinking agent used (number of moles) may be determined accordingly. The obtained gel-like material can be used as it is as the main material, but water is removed by normal separation means such as centrifugation and filtration, washed with water as necessary, and then a vacuum belt dryer or freeze-dry. It may be dried with a machine and used as a powder product.

Next, the case of adding a schiffing agent will be described. The Schiffing agent modifies the amino group by performing a Schiffing reaction with the residual amino group in the protein cross-linked product. By adding a Schiffing agent, the present material can be obtained as a gel-like material as in the case of the alkylating agent. Examples of the schiffing agent include conventionally known ones, such as aldehydes. The obtained gel-like material can be separated and dried as described above.

The case where an acid is further added will be described. Acid is added to the aqueous phase to adjust the pH of the phase below the isoelectric point of the starting protein. As a result, the material that is soluble in the organic solvent and insoluble in water is precipitated. The resulting precipitate can be pulverized by the same separating means and drying means as above. Any known acid can be used, for example, hydrochloric acid, citric acid, succinic acid, acetic acid, lactic acid, tartaric acid, fumaric acid, malic acid, adipic acid, glucono delta lactone,
Examples thereof include gluconic acid, ascorbic acid, levulinic acid and phthalic acid. In addition, if the crosslinking is insufficient or the hydrophobicity is insufficient, a precipitate is deposited even if the pH is lowered by adding an acid, but this material may not be produced. Therefore,
When the acid is used alone, the amount of the crosslinking agent used in the previous step is about 2 times or more the usual amount, preferably about 2 to 3 times.

The above-mentioned alkylating agent, Schiffing agent and acid can be used alone, but two or three of them can be used in combination.

In the present invention, for the purpose of advantageously promoting a reaction such as a crosslinking reaction, accelerating the reaction rate, and improving the performance and yield of this material, for example,
The protein may be pretreated prior to reacting the protein with the crosslinking agent.

The pretreatment method of the above-mentioned protein is not particularly limited, but examples thereof include dilution, electrodialysis, heating, pH adjustment, centrifugation, filtration and the like, and one of these may be carried out, or 2 You may perform it combining suitably more than one kind. More specifically, it is described in Japanese Patent Application Nos. 2-418876 and 4-53466.

The dilution is mainly carried out with water, and for example, in the case of egg white protein, the dilution ratio is usually 2 times or more, preferably about 2 to 5 times, more preferably about 2 to 3 times. Examples of water used for dilution include deionized water, distilled water, pure water and tap water.

Electrodialysis is carried out to reduce the ionic concentration of the protein or its diluent. Electrodialysis can be performed according to a conventional method. In addition, it is preferable to adjust the pH of the protein or its dilution prior to performing electrodialysis. In this case, it is preferable that the pH of the protein or its dilution is in the acidic to neutral range (usually about pH 5-8, preferably about 6-7). An acid is used for such pH adjustment. The acid to be added is not particularly limited, but an acid that becomes an acidulant in the food additive is suitable. Specific examples of such acid include citric acid, succinic acid, acetic acid,
Lactic acid, tartaric acid, fumaric acid, malic acid, adipic acid, glucono delta lactone, gluconic acid, ascorbic acid, hydrochloric acid and the like can be exemplified.

The heating is not particularly limited, but is usually about 75 ° C.
It takes about 30 minutes or more. The pH of the egg white or its diluted product before heating is preferably in the alkaline range (usually pH 8 or higher, preferably 9 or higher). Therefore, when the pH is lower than the above range, particularly when electrodialysis is performed and the pH is in the acidic or neutral range, the pH range may be adjusted by using an appropriate alkaline agent.
As the alkaline agent, conventionally known ones can be widely used,
Examples thereof include sodium hydroxide, calcium carbonate, ammonium carbonate, sodium carbonate, ammonium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, magnesium carbonate and polyphosphoric acid.

When aggregates or precipitates are deposited by the above-mentioned treatments such as dilution, electrodialysis, heating, etc., it is preferable to remove them by an ordinary separating means. For example, it may be filtered with a filter or centrifuged.

When the protein is reacted with the cross-linking agent, the pH of the protein or its diluent is in the alkaline range (usually p
H8 or more, preferably about 10 to 12). Therefore, when the pH is lower than the above range, the pH range may be adjusted by adding an appropriate alkaline agent.

Further, the pH may be adjusted prior to the reaction of the crosslinked product of the protein with the alkylating agent or the Schiffing agent.

The following is an example of a preferred embodiment for obtaining this material.

(A) The pH of egg white or a water dilution thereof (egg white concentration of about 1 to 5% by weight) is adjusted to an acidic or neutral range,
The ionic strength is reduced by electrodialysis, the pH of the resulting solution is adjusted to 9.0 or higher, and heating is performed.

(B) Another protein is added to the heated egg white aqueous solution and mixed to prepare a protein mixed aqueous solution.

(C) p of the heated protein mixed aqueous solution
Adjust H to an alkaline range (for example, pH 10 to 12).

(D) The protein mixed aqueous solution after pH adjustment and the organic solvent solution of the cross-linking agent are mixed and vigorously stirred and allowed to stand to separate into an aqueous phase and an oil phase.

(E) Aqueous phase (usually about pH 6.5-9)
Is collected and the pH is adjusted to an alkaline range (for example, about pH 12).

(F) Further adding an alkylating agent with stirring,
The precipitated gel-like substance is separated by centrifugation, washed with water and freeze-dried.

The material thus obtained is confirmed to be a protein from the results of amino acid analysis. The greatest feature of this material is that it is soluble in organic solvents such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide (DMA), phenol, formic acid, etc., but not water, even though this material is a protein. It is a point. However, when this material is dispersed in water and the pH is adjusted to the alkaline side (about 6 or more), it changes to a water-soluble material that is insoluble in organic solvents. Then, when the pH of the aqueous solution is again adjusted to be equal to or lower than the isoelectric point of this material, the material is changed to a material that is soluble in an organic solvent and insoluble in water. This change occurs reversibly any number of times by adjusting the pH as described above. Further, this material has an extremely excellent substance adsorption capacity.

[0038]

【The invention's effect】

(1) According to the present invention, by using two or more kinds of raw material proteins in combination, the function of the obtained organic solvent-soluble raw material can be improved or the yield of the raw material can be increased. . For example, if you use gelatin and egg white together,
The obtained material is provided with a protective colloid property of gelatin, and the yield is significantly improved as compared with the case where egg white is used alone.

(2) According to the present invention, Japanese Patent Application No. 4-53
It is possible to provide a protein material having a higher solubility in an organic solvent than that described in No. 466. When the raw material and the synthetic resin are dissolved and mixed in an organic solvent and the solvent is removed, the raw material disperses very uniformly in the resin, so that the protein is far superior to the case of mixing fine resin powder with the resin. Can perform the desired function.

(3) The present material has an excellent adsorptivity and is also characterized in that its physical properties are reversibly changed by the change of pH. By utilizing this property, the present material can be used as a substance adsorption / desorption agent. As the utilization of this adsorption / desorption property, for example, separation of substances that cause coloration or pollution from wastewater, recovery of useful substances, application of titanium dioxide or zirconium oxide as an ultraviolet absorber to fibers and cosmetics, etc. Etc. are possible.

(4) Since this material is soluble in an organic solvent, it can be dispersed very uniformly in a plastic film, sheet, tube, etc., and a new function can be imparted to the plastic.

For example, when this material is applied to synthetic fibers for clothes, it gives a non-greasy touch like natural materials, as compared with fibers made of plastic only, balance of inhalation and release of moisture, heat retention, etc. The excellent performance that the film has a good property and is less likely to cause dew condensation is exhibited.

Further, puffs for cosmetics and the like are conventionally manufactured by coagulating and vulcanizing porous rubber such as latex or by molding urethane foam, but they are satisfactory in terms of moist feeling on the surface, feel of the skin, etc. I haven't got what I want. Therefore, by adding an organic solvent solution of the present material when producing a urethane foam, a sponge (puff) having a moist feeling similar to silk and a smooth texture can be obtained. It should be noted that the production of the urethane foam may be carried out according to the conventional method, and the addition amount of this material may be appropriately selected according to the purpose of use of the sponge obtained.

(5) Since the present material has a property due to a functional group such as a carboxyl group in its molecule, it can be used for various purposes. For example, this material has a surfactant effect and can be used as a surfactant, a fiber auxiliary agent, an antistatic agent, a dye fixing agent, a dye auxiliary agent, and the like. Further, (the carboxyl group of this material) and esters such as ascorbic acid and pantothenic acid can be used as raw materials for cosmetics. This material can also be used as a raw material for a chelating agent that traps metal ions.

In addition, the present material is, for example, ink jet, recording paper, artificial skin, artificial organ, artificial leather, fixing agent for analytical / physical examination, coating agent for agricultural chemicals / fertilizer, biosensor for LB film formation. , Artificial functional membranes (for example, artificial cell membranes), microcapsule materials, drug delivery systems, etc.

[0046]

EXAMPLES The present invention will be further clarified by the following examples.

Example 1 800 g of frozen chicken egg white was left to thaw in warm water at 35 ° C., thawed, passed through a 32 mesh filter, diluted 2.5 times with tap water, and then gently stirred to 2M-. The pH was adjusted to 6.8 by adding citric acid. This adjusted egg white is passed through a 42-mesh filter and then centrifuged (7,000 rp).
m × 10 minutes), and the precipitate was removed by adjusting the pH.
The obtained supernatant is electrodialyzed (electrodialysis: CS-O type, trade name, manufactured by Asahi Glass Co., Ltd., flow rate: 250 liters / h
r. , Constant voltage: 14 V), and the electric conductivity was 950 μS / cm. The dialysate was adjusted to pH 10 by adding 1N and 6N sodium hydroxide. This was heated in boiling water for 30 minutes and cooled to room temperature to obtain an egg white liquid that passed through a 100-mesh filter. The absorbance of this egg white liquor is 0.37
0 (280 nm), and the egg white concentration was about 4%.

3 g of gelatin [produced by Nitta Gelatin Co., Ltd., molecular weight 15000] was dissolved in 800 ml of the obtained egg white liquor, and ionic water was added to make 1 liter. 1N and 6N sodium hydroxide were added to adjust pH to 12. did. The mixture was warmed to 45 ° C. On the other hand, 18.4 g of toluene diisocyanate was mixed with 300 g of chloroform, and this was added to the mixture solution which was being heated, and the mixture was stirred for 2 hours and then left at room temperature to separate into an aqueous phase and a chloroform phase. The aqueous phase was separated by centrifugation (8000 rpm x 10 minutes).

When this supernatant is adjusted to pH 4 with citric acid, this material precipitates, so it is centrifuged again (10,000 r
pm × 15 minutes). The separated material was easily dissolved in DMF, and when this solution was put in water, protein precipitation was observed. The powder obtained by freeze-drying this precipitate was also soluble in DMF, and when this solution was also put in water, precipitation of protein was observed.

Example 2 In the same manner as in Example 1, 5 to 20% by weight of the egg white amount of gelatin was added to produce this material.

Ionized water was added to 4 g of the obtained raw material to make a total volume of 1 liter, and 1N and 6N sodium hydroxide was added with stirring to adjust the pH to 7 to dissolve the raw material in water. To this solution, 1 ml of paprika pigment [natural emulsion of paprika pigment, trade name: paprika base 150, manufactured by Sanei Chemical Industry Co., Ltd.] was added and mixed, and 2M citric acid was added to adjust pH to 4 at room temperature. When left to stand, this material adsorbing the paprika pigment was deposited. After standing at room temperature for 2 hours, the absorbance (470 nm) of the supernatant was measured to examine the residual amount of paprika dye. The results are shown in Table 1.

For comparison, a functional protein material (that is, Japanese Patent Application No. 4-204) was prepared in the same manner as in Example 1 except that gelatin was not added.
The material described in No. 53466) was obtained and treated in the same manner as above to examine the residual amount of humprika pigment. The results are also shown in Table 1.

[0053]

[Table 1]

From Table 1, it can be seen that the larger the amount of gelatin added, the smaller the residual amount of paprika dye (the lower the absorbance).
Therefore, it is presumed that the protective colloid property of gelatin is exerted, and the adsorptivity increases as the amount of gelatin increases.
That is, according to this method, a protein material having a function of being soluble in an organic solvent while retaining the original function of gelatin can be obtained.

Example 3 To 2.5 g of the material obtained in Example 1 was added ionic water to make a total volume of 1 liter, and 1N and 6N sodium hydroxide was added to adjust the pH to 7 to dissolve the material in water. Let 1.5 g of titanium dioxide (trade name: TAF-100, particle diameter 0.05 μm, manufactured by Fuji Titanium Industry Co., Ltd.) in this solution.
And ultrasonic treatment and disperser treatment for each 10
Do this for a minute to disperse this material and titanium dioxide, then p
Adjust to H4 and deposit this material that has adsorbed titanium dioxide,
Allowed to settle. Centrifuge this (10000 rpm × 20
Then, the material adsorbing titanium dioxide was collected.

The product name of the ultrasonic generator is "BRA".
NSON 2200 "(manufactured by Yamato Scientific Co., Ltd.) and a trade name" Ultra Disperser Model LK-22 "(manufactured by Yamato Scientific Co., Ltd.) were used.

This material adsorbing titanium dioxide was dispersed in ionic water, and the ultraviolet absorption at 200 to 400 nm was measured. The results are shown in Fig. 1. From FIG. 1, it can be seen that the titanium dioxide-adsorbing material has an ultraviolet adsorption spectrum similar to that of titanium dioxide itself. Therefore, it is clear that titanium dioxide is adsorbed on this material.

Example 4 Nylon 66 chips were dissolved in formic acid for one day and dissolved in 20%.
A nylon-formic acid solution (solution A) was prepared. Further, the material obtained in Example 1 was dissolved in formic acid to prepare a 3% functional protein-formic acid solution (solution B).

2 ml of solution B was added to 10 g of solution A and stirred so as to be uniform, to prepare a nylon solution containing about 3% of this material. When this nylon solution was spread on a flat glass plate and air-dried to disperse the solvent, a white film having a weak tensile force was formed.

When this white film was heated and pressed with an impulse sealer (trade name: impulse sealer F1-200-10w type), a transparent and tensile strength nylon film was obtained. This product had a moisture permeability that was not found in nylon alone.

Example 5 800 g of frozen chicken egg white was left to thaw in warm water of 35 ° C. for 8 hours, thawed, filtered with a 32 mesh filter, diluted 2.5 times with tap water, and stirred gently. The pH was adjusted to 6.8 by adding 2M-citric acid. 42 of this adjusted egg white
Pass through a mesh filter and then centrifuge (7000
rpm × 10 minutes) to remove the precipitate by adjusting the pH.

The obtained supernatant was electrodialyzed (electrodialysis: C
S-O type, trade name, manufactured by Asahi Glass Co., Ltd., flow rate: 250 liters / hr. , Constant voltage: 14V) and conductivity 985μ
It was S / cm. The dialysate was adjusted to pH 10 with 1N and 6N sodium hydroxide. This is heated in boiling water for 30 minutes, cooled to room temperature, filtered through a 200 mesh filter, and has an absorbance of 0.386 (280n
m) egg white liquor was obtained and diluted to pH12. The absorbance of this diluted egg white liquid is 0.163 (280 n
m).

400 ml of the diluted egg white liquor obtained above was added to whey protein [trade name: DF-WPC, Meiji Dairy Co., Ltd.].
Made, partially defatted whey protein]
Was adjusted to 12. The absorbance at this time is 0.328 (28
0 nm). The mixed solution was heated to 45 ° C., and 7 g of toluene diisocyanate and 300 ml of chloroform were added thereto.
After the mixture with g was added and stirred for 2 hours, the mixture was allowed to stand at room temperature to separate into an aqueous phase and a chloroform phase, and the aqueous phase was separated. If citric acid is added to this aqueous phase to adjust the pH to 4, this material will precipitate and precipitate, so centrifuge (10,000 r
This material was collected by (pm × 30 minutes).

This material was easily dissolved in DMF, and when this solution was put in water, precipitation of protein was observed. The powder obtained by freeze-drying this material was also soluble in DMF, and when this solution was put in water, protein precipitation was observed.

Example 6 This material containing chicken egg white and gelatin obtained in Example 1 as raw materials, the chicken egg white obtained in Example 5 and this material containing whey protein as raw materials, and chicken egg white only as raw materials The solubility of the raw material (Example 2) in a solvent (DMF) was examined. The results are shown in Table 2.

[0066]

[Table 2]

It can be seen from Table 2 that the combined use of two kinds of proteins as the raw materials increases the solubility of the obtained protein raw material in the organic solvent.

Example 7 To 4 g of the raw material obtained in Example 5 was added ionized water to make a total volume of 1 liter, and while stirring, 1N and 6N sodium hydroxide was added to adjust the pH to 7 to dissolve the raw material. It was Add 1 ml of paprika dye to this solution [paprika base 15
0] is added and mixed, and 2M citric acid is added to adjust the pH to 3.
When this was adjusted to 3 and allowed to stand at room temperature, this material on which the paprika pigment was adsorbed was deposited.

Example 8 800 g of frozen chicken egg white was left to thaw in warm water at 35 ° C. for 8 hours, thawed, filtered through a 32 mesh filter, diluted 4 times with tap water, and centrifuged (7,000 rpm × 10 minutes).
Then, the pH was adjusted to 12. In 400 ml of this diluted egg white liquor, 7 g of whey protein [trade name: DF-WPC, partially defatted whey protein, manufactured by Meiji Dairy Co., Ltd.] was dissolved, and the pH was adjusted again.
Was adjusted to 12. The absorbance at this time is 0.355 (28
0 nm).

This protein mixture was heated to 45 ° C., and 7 g of toluene diisocyanate and 300 g of chloroform were added thereto.
After the mixture was added and stirred for 2 hours, the mixture was allowed to stand at room temperature and separated into an aqueous phase and a chloroform phase. The separated aqueous phase is centrifuged (8000 rpm x 10 minutes) to remove impurities, and then 2M-citric acid is added to lower the pH to 3.5. This material precipitates and precipitates. Therefore, centrifugation (8000 rp) is performed.
This material was collected. This material was easily soluble in DMF and insoluble in water.

Example 9 This material was prepared in the same manner as in Example 8 except that 10 g of toluene diisocyanate was used instead of the mixture of 7 g of toluene diisocyanate and 300 g of chloroform in Example 8, and that the material was easily soluble in DMF and insoluble in water. It was

[Brief description of drawings]

FIG. 1 200 to 40 agglomerates of this material and titanium dioxide
It is a figure which shows an ultraviolet absorption spectrum of 0 nm.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadashi Tsukiyama 463 Kagasuno, Kawauchi Town, Tokushima City, Tokushima Prefecture Otsuka Chemical Co., Ltd., Tokushima Plant (56) References JP-A-50-94000 (JP, A) JP-A 52-25800 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07K 1/00-1/10 C07K 14/415-14/765 BIOSIS (DIALOG)

Claims (3)

(57) [Claims] 1. At least two proteins, water and diiso
A process for producing a functional protein material, which comprises mixing and crosslinking a cyanate compound, and then reacting the resulting crosslinked protein with at least one selected from an alkylating agent, a Schiffing agent and an acid. 2. The method for producing a functional protein material according to claim 1, wherein the protein is a protein or peptide having a free amino group. 3. The functionality according to claim 2, wherein the protein or peptide having a free amino group is at least one selected from egg white protein of chicken, quail, duck or goose egg, whey protein, serum albumin and casein. A method of manufacturing protein materials.