JP2002302499A - Granular silk fibroin and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain granular silk fibroin whose existence can visibly be confirmed, which is suitable in the fields of cosmetics foods, industrial materials, and the like, permits the enjoyment of a proper granular touch, and the like, therefore has the possibility of various hidden uses, and is expected to be developed for various uses in the future. SOLUTION: The granular silk fibroin consisting mainly of finely powdery silk fibroin is characterized by being granulated through a granular layer containing silk fibroin as a main component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a granular silk fibroin and a method for producing the same, and in particular, a granular silk fibroin suitable for the fields of cosmetics, foods, industrial materials, etc., a method for producing the same, and a cosmetic containing the same. And foods containing the same.

[0002]

2. Description of the Related Art Silk fibroin has a moderate moisture absorption / desorption property,
Because of its characteristics such as affinity for skin and hair and ultraviolet absorption, it is widely used in the form of powders, aqueous solutions or derivatives thereof. It has a proven track record for prescription in cosmetics such as shampoo and soap, and for use in industrial materials such as kneading in paints. Many applications to food such as bread, noodles, candy, and dressings are also found.

[0003] The powder of the silk fibroin used in these is disclosed in Japanese Patent Publication No.
According to JP-A-6-4947 and JP-B-58-38449, a fibrous silk fibroin powder obtained by pulverizing a silk raw material as it is or embrittled by a chemical treatment, and converting the silk raw material into an appropriate concentrated neutral salt, etc. A granular silk fibroin powder obtained by pulverizing gel-like silk fibroin obtained by spray-drying a solution dialyzed colloid solution, and a colloid obtained by dissolving a silk raw material in an appropriate inorganic neutral salt or alkaline aqueous solution and then dialyzing or not. From the solution, the addition of coagulable salt, air blowing, isoelectric coagulation, ultrasonic treatment or stirring at a high shear deformation rate to coagulate and precipitate silk fibroin, dewatering, drying and pulverized silk fibroin powder are disclosed. ing.

[0004] The silk fibroin powder thus obtained is used after being pulverized to about 1 µm for small grades and to about 50 µm for large grades in terms of average particle size. Of these, those with large grades are used exclusively as raw materials for reprocessing, and most of those actually available in the market as silk powder have an average particle size of about 5 μm. This means that the particles have a minimum particle size so that they can be uniformly mixed with other pigments and other substances to be mixed and do not have a foreign-body sensation when mixed and formulated into cosmetics and paints.

On the other hand, among silk fibroin, an aqueous solution of silk fibroin is disclosed in Japanese Patent Publication No. 57-4723.
Group consisting of copper-ethylenediamine aqueous solution, copper hydroxide-ammonia aqueous solution, copper hydroxide-alkali-glycerin aqueous solution, lithium bromide aqueous solution, calcium or magnesium or zinc hydrochloride or nitrate or thiocyanate aqueous solution, sodium thiocyanate aqueous solution A method for producing a silk fibroin aqueous solution, comprising dissolving a refined silk raw material in at least one solvent selected from the group consisting of:

The silk fibroin aqueous solution thus obtained is sold as it is or in a form in which the molecular weight and the fibroin concentration are adjusted as required. Numerous types are also sold in the form of derivatives using the aqueous solution as a starting material and by adding various functional groups.

[0007] Granular silk fibroin is disclosed in JP-A-8-268905. Silk fibroin formed into granules, when mixed with cosmetic scrubbing agents and massage agents, can visually confirm its existence and enjoy a moderate particle feeling. Usage expansion is expected. But,
The granules obtained by the conventional method are not preferred in that they must contain a certain amount of other components as a binder in order to granulate the pigment in addition to the silk fibroin which is the main component of the desired silk fibroin granules. Therefore, there has been a demand for the development of granular silk fibroin containing as little as possible other than silk fibroin and active ingredients.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a granular silk fibroin suitable particularly in the fields of cosmetics, foods, industrial materials, and the like, and a method of industrially easily and inexpensively producing a granular silk fibroin. Is to provide.

[0009]

An object of the present invention is to provide a granular silk fibroin mainly composed of finely powdered silk fibroin, which is characterized in that it is granulated through a granulation layer mainly composed of silk fibroin. And granular silk fibroin.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The fine powdered silk fibroin used in the present invention is a silk fibroin having an average particle diameter of 1 μm to 50 μm.
It is formed in the form of a powder having a size of m, but the size is not particularly limited. Any generally available finely powdered silk fibroin may be used alone or in combination of two or more as long as it is water-insoluble. Tokuhei 5-7926
Fine powdered silk fibroin obtained by complexing silk fibroin with other active ingredients as described in JP-A No. 0, JP-A-4-193812 and JP-A-7-267822 may be used. Also, a water-soluble fine powdered silk fibroin peptide as disclosed in Japanese Patent Publication No. 6-4679 is poured into an organic solvent such as ethyl alcohol with stirring, and then the solvent is removed and dried to remove water. Can be used without any problem.

The silk fibroin component used as the raw material of the finely powdered silk fibroin and the aqueous solution of silk fibroin used in the present invention may be obtained by a conventional method such as eyebrows, raw silk, eyebrows waste, raw silk waste, screws, fried cotton, silk cloth waste, and boulet. According to the above, if necessary, sericin can be removed in warm water or in warm water in the presence of an enzyme in the presence of an activator and dried.

[0013] Examples of the method for producing fine powdered silk fibroin include a method of pulverizing the above-mentioned silk raw material as it is, a method of pulverizing embrittled one by a chemical treatment, and a method of applying the above-mentioned silk raw material to a suitable concentrated neutral A method of pulverizing gel-like silk fibroin obtained by spray-drying a colloid solution dissolved and dialyzed in salt or the like,
From the colloid solution obtained with or without dialysis after dissolving the silk raw material in a suitable inorganic neutral salt or alkaline aqueous solution,
A method of coagulating and depositing silk fibroin by addition of a coagulable salt, air blowing, isoelectric coagulation, ultrasonic treatment, or stirring at a high shear deformation rate, followed by dehydration, drying and pulverization is exemplified.

An example of a method for coagulating and depositing a silk fibroin component from a solution in which silk fibroin is dissolved is described below.

After refining the above silk fibroin raw material, it is added to a solvent comprising the following aqueous solution, and uniformly dissolved at a temperature of 60 to 95 ° C., preferably 70 to 85 ° C. while stirring in a device such as a kneader. The solvent ratio is usually 2 to 50, preferably 3 to 30, with respect to the silk raw material 1. Solvents applicable to the present invention include aqueous solutions of copper-ethylenediamine, aqueous solutions of copper hydroxide-ammonia (Schweizer reagent), aqueous solutions of copper hydroxide-alkali-glycerin (Roe's reagent), aqueous solutions of lithium bromide, and calcium, magnesium or zinc hydrochlorides. , Nitrate or thiocyanate aqueous solution and sodium thiocyanate aqueous solution, and calcium or magnesium hydrochloride or nitrate is preferred in view of cost and use. The concentration of these aqueous solutions depends on the type of solvent used,
Depends on temperature etc., concentration of metal salt etc. is usually 10 ~ 80%
(Mass), preferably 20 to 40% (mass). 80%
Although it dissolves even if it is (mass) or more, there is no substantial difference in the produced silk solution, which is a problem in terms of economy.

In order to obtain a high-purity silk fibroin solution from the obtained silk solution, dialysis is performed. The dialysis uses a dialysis membrane typified by a cellophane membrane or a dialyzer using hollow fibers to remove the salts and the like almost completely. In this case, in order to narrow the molecular weight distribution of the target silk fibroin as much as possible, the proportion of the water-soluble peptide having an α-structure was set to 50% by mass.
For the above adjustment, it is necessary to specify the dialysis amount and the dialysis membrane area. That is, desalting is performed using a multilayer structure or a hollow fiber bundle structure that satisfies Formula 1.

[0017]

[Formula 1] Membrane surface area (square cm) / priming capacity (cubic
cm) ≧ 10 where the priming volume indicates the internal volume between the dialysis tube or membrane.

When the above value is less than 10, the membrane separation is not carried out quickly, so that the residence time in the dialyzer becomes long, and the resulting fibroin solution often has already started spoiling. In such a case, the silk fibroin protein becomes water-insoluble (β structure) due to denaturation due to putrefaction, and it is difficult to make it soluble in cold water again.

In particular, in order to smoothly and economically perform the dialysis in the present invention, the above numerical value is preferably 30 or more, particularly preferably 50 or more. In order to satisfy the condition, for example, in the case of a hollow fiber bundle structure, the diameter of the hollow fiber needs to be 4 mm or less. The dialysate obtained by the method of the present invention has a very low residual salt concentration of 0.003 to 0.06% (mass), and particularly when the diameter of the hollow fiber is about 0.2 mm, the above value becomes about 200, and the dialysate is used in a dialyzer. This can be achieved with a residence time of 10 minutes, from which a very high quality silk fibroin solution can be obtained.

The fibroin concentration of the silk fibroin solution at that time is usually 1 to 30% (by mass), preferably 2%.
20% (mass), optionally concentrated. 1%
If the amount is less than (mass), concentration is required in the subsequent step, which is uneconomical. If the amount is more than 30% (mass), the viscosity becomes high and the reaction or operation becomes impossible.

The silk fibroin solution having the adjusted fibroin concentration is then precipitated in a coagulation step. The coagulation step is to add a coagulable salt to the silk fibroin solution,
Silk fibroin is precipitated in the solution by using at least one method such as air blowing, isoelectric solidification, ultrasonic treatment, or stirring at a high shear deformation rate. The obtained silk fibroin precipitate is dehydrated, dried and pulverized to obtain fine powdered silk fibroin.

In the granular fibroin of the present invention, silk fibroin alone may be used as the powder component, but any water-insoluble fine powder component may be used in combination as long as the properties of silk fibroin are not impaired. Can be. For example,
When used in cosmetics and foods, coloring may be required in some cases. In such a case, other particulate components such as pigments may be added according to the color to be colored. Those that can be used in combination are red iron oxide, activated carbon, yellow iron oxide, black iron oxide,
Colored pigments such as chromium oxide, carbon black, ultramarine and navy blue, white pigments such as zinc oxide, titanium oxide, cerium oxide, and barium sulfate; extender pigments such as talc, mica, sericite, kaolin, and barium sulfate, titanium mica Examples include, but are not limited to, pigments such as pearl pigments such as carmine-treated titanium mica, bismuth oxychloride, and pearl pigments such as fish scale foil, and food colorings, but are not limited to those usually used in cosmetics and foods. Any can be used together.

The granular silk fibroin of the present invention can be used in combination with other active ingredients of silk fibroin. In the present invention, the active ingredient refers to a component different from silk fibroin to be added for the purpose of imparting functionality to the granules, and refers to a component directly contributing to function and efficacy and a component contributing to product safety. Specifically, it refers to surfactants, humectants, whitening agents, anti-inflammatory agents, preservatives and the like. These active ingredients may be compounded with finely powdered silk fibroin before granulating into granules, or may be mixed in a granulating agent described below.

Next, the silk fibroin solution used as a granulating agent in the present invention will be described.

The silk fibroin used as a granulating agent in the present invention refers to silk fibroin or a product obtained by hydrolyzing the same with an enzyme, acid or alkali, and is generally dispersed in a silk fibroin solution or a solvent solution dissolved in a solvent. Use a colloidal solution. It is desirable to use an aqueous solvent as a solvent and to dissolve or disperse silk fibroin in the solvent.

The production method is not particularly limited, but it is preferable to obtain an aqueous solution or a colloid solution of silk fibroin by dissolving the raw material of silk fibroin in the aqueous solution and dialyzing the silk fibroin solution.

The silk fibroin concentration and the average molecular weight of the aqueous solution or colloid solution of silk fibroin used as a granulating agent directly influence the hardness of granular silk fibroin. In general, the higher the silk fibroin concentration and the higher the average molecular weight, the higher the hardness. Therefore, if the average molecular weight is reduced, the hardness of the granular silk fibroin obtained is further reduced, and a granular silk fibroin which disintegrates with a small external force is obtained. Similarly, if the fibroin concentration is increased, the hardness of the obtained granular silk fibroin increases, and a granular silk fibroin that can withstand a larger external force is obtained.
In addition, when adjusting the average molecular weight of silk fibroin, this is hydrolyzed using enzymes, acids or alkalis. Therefore, if necessary, the aqueous solution is hydrolyzed with an enzyme, acid or alkali to deactivate or neutralize the enzyme and desalt (or not), and adjust the average molecular weight of the silk fibroin aqueous solution or colloid solution. I do.

Although the silk fibroin solution thus obtained can be used alone as a granulating agent, other general water-based granulating agents such as gelatin, arabic gum, shellac, methylcellulose and the like can be used. It can also be used by optionally mixing with a cellulose derivative such as hydroxypropyl cellulose, polyvinyl alcohol, sodium alginate, an emulsion of acrylic acid polymer and the like. These additives influence the strength of the granules. But,
Less of these additives are preferred in terms of increasing the proportion of silk components in the product.

The granulating apparatus used for granulation using these components is not particularly limited, and examples thereof include a rolling type, an extrusion type, a stirring type and a fluidized bed type. In each case, granulation is performed using a granulating agent by a granulation method according to a standard method. Next, the obtained granulated product is dried by a method such as fluidized-bed drying or tray drying in order to remove moisture contained in the granulating agent.

The silk fibroin granules in the present invention are coated by a generally known method, for example, by using a water repellent or moisture proof agent such as a silicon or fluorine type to impart water resistance during granulation or before and after drying. Can also be applied.

For finishing, the particle size is adjusted by a sieving machine or the like as necessary to obtain granular silk fibroin.

【The invention's effect】

The granular silk fibroin obtained as described above is characterized in that the ratio of the silk component containing the silk component is higher than that in the related art. In addition, when this granular silk fibroin is blended into scrubbing agents for cosmetics, various cleaning agents and massage agents, it can make use of the granular feeling and visual sense unique to granules,
It enables the production of high-quality cosmetics with high affinity for skin and high moisturizing properties, which are characteristics of silk fibroin. Also, when mixed with foods, the ratio of substances other than silk fibroin is lower than before, so it can meet nutritional and health needs, and enjoy the unique texture and sight of granules. To be able to produce food that can.

【Example】

Hereinafter, an example of the present invention will be described with reference to examples. In addition,% notation in an example represents mass%.

The hardness described in the examples was measured by the following method. Gently take any one of the granular silk fibroin, sandwich the fibroin between a pair of smooth upper and lower glass plates, one of which is fixed and the other moves vertically to this,
A load is applied on a movable glass plate to crack the fibroin.
The deformation due to the collapse is visually confirmed, and the weight value at the time when the fibroin is deformed is read. The operation was continuously measured for 10 grains, and the average of the weight values was determined as the hardness [g / grain] of the fibroin.
And

[Example 1] A twisting waste as a raw material of an aqueous solution of silk fibroin was replaced with a 1.0% Marcel soap solution (bath ratio 30 times).
For 1 hour to remove sericin, washed with water and dried with hot air. Next, the de-sericin twist yarn waste was kneaded and dissolved in a heated 38.0% calcium chloride aqueous solution at a bath ratio of 5 times using a kneader. After filtration to remove impurities, dialysis and desalting were performed using a hollow fiber type dialysis device to obtain an aqueous solution of silk fibroin. The fibroin concentration of the obtained aqueous solution of silk fibroin was 5.9%.

A fine powdered silk fibroin (silk powder CN manufactured by Kanebo Co., Ltd.,
100 g of an average particle diameter of 4.3 μm) was stirred and granulated using the above-mentioned aqueous solution of silk fibroin as a granulating agent. The required fibroin aqueous solution was 45 g. After granulation, the product is dried in a fluidized bed dryer until the product temperature reaches 40 ° C.
Fine particles were cut at 00 μm to obtain products. The recovered granular silk fibroin was 72 g, and the yield was 70%. The hardness of the obtained product was 2.8 g / grain.

Example 2 5 g of caustic soda was added to 1000 g of the aqueous solution of silk fibroin obtained in Example 1 and the mixture was heated at 85 ° C. under mild stirring.
It was hydrolyzed for 0 minutes and neutralized with hydrochloric acid. After cooling, pore size 0.4
The solution was filtered through a 5 μm membrane filter. In 90 g of the obtained hydrolyzed silk fibroin solution, 10 g of hydroxypropylcellulose (Nisso HPC-L manufactured by Nippon Soda Co., Ltd.) was dissolved to prepare a granulating agent.

90 g of the finely powdered silk fibroin used in Example 1 was added to talc (Asada Talc JA-1 manufactured by Asada Flour Milling Co., Ltd.).
3R) 10 g of powder was mixed, and the granulating agent prepared previously was added thereto, followed by stirring and granulating. After granulation, it was dried in a tray dryer until it reached a constant weight. Thereafter, coarse particles were cut at 500 μm, and fine powder was cut at 250 μm to adjust the particle size to obtain a product. The required granulation amount was 36 g, and the yield was 48%. The hardness of the obtained product was 165.2 g / grain.

Example 3 12 g of caustic soda was added to 1000 g of the aqueous solution of silk fibroin obtained in Example 1 and the mixture was stirred at 85 ° C. under mild stirring.
It was hydrolyzed for 60 minutes and neutralized with hydrochloric acid. After cooling, the pore size is 0.
The solution was filtered through a 45 μm membrane filter, and then concentrated under reduced pressure using a rotary evaporator. The obtained concentrate was a transparent brown viscous liquid and had a silk fibroin protein concentration of 46%.

From a colloidal silk fibroin solution substantially free of sericin protein, silk fibroin was recrystallized physicochemically and then mechanically pulverized into fine powdered silk fibroin (silk powder IM, manufactured by Kanebo Co., 100 g of 6.8 μm in diameter) and 238 g of the concentrated aqueous solution of silk fibroin previously prepared as a granulating agent were kneaded to obtain an extruded granulation. After granulation, it was dried in a tray dryer until it reached a constant weight. Thereafter, coarse particles were cut at 2 mm, and fine particles were cut at 1 mm to adjust the particle size to obtain a product. The product obtained is 159
g, the yield was 76% and the hardness was 101.4 g / grain.

The obtained granules have a unique feeling of use, touch, and sight of the granules such as moderate hardness and graininess, and contain a silk component at a higher ratio than in the past. It is suitable for applications such as food.

Hereinafter, an example of a cosmetic formulation according to the present invention will be described with reference to formulation examples. In addition,% notation in an example represents mass%.

1. 1. Sodium lauroyl glutamate balance 2. Sodium starch octenyl succinate 10 3. Palm oil fatty acid ethyl ester sodium sulfonate 10 Talc 20 5. 5. Dipotassium glycyrrhizinate 0.5 Granules of Example 2 (Product of the Invention) 5 First, 1 to 5 were granulated in advance using a 5% by mass aqueous solution of hydroxypropylcellulose as a granulating agent using a mixer. 250 μm or less of 500 μm or less
The resulting mixture was sieved and sized, and 6 was added thereto.

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Claims (5)

[Claims] 1. Granular silk fibroin mainly composed of fine powdered silk fibroin, characterized by being granulated through a granulation layer mainly composed of silk fibroin. 2. A granulating agent for granulating a powder component into granules, which is mainly composed of silk fibroin. 3. A method for producing granular silk fibroin, wherein a powder component mainly composed of fine powdered silk fibroin is granulated with a granulating agent containing silk fibroin as a main component. 4. A cosmetic comprising the granular silk fibroin of claim 1. 5. A food containing the granular silk fibroin of claim 1.