JPH10337402A - Method for removing protein from liquid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove protein from a protein-contg. liq. material in a profitable manner by bringing the liq. material into contact with a material coated with chitosan deposited from a chitosan soln. SOLUTION: In various protein removing processes in the treatment of waste liquor in a food plant, a material coated with chitosan deposited from a chitosan soln. is used as a flocculant, etc., and the waste liquor is brought into contact with the chitosan-coated material to flocculate and remove protein. It is preferable that a silica sol is added to the protein-contg. liq. material to flocculate the protein, the chitosan-coated material is added to the flocculated protein and pressure filtration or centrifugal filtration is carried out. The chitosan- coated material is preferably obtd. by adding a core material such as cellulose to an acidic aq. soln. of chitosan and then adding an alkali to deposit the chitosan.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing proteins from a liquid using chitosan.

[0002]

2. Description of the Related Art Coagulants and filter aids for coagulating and filtering proteins are used in various protein removal processes such as sake and soy sauce brewing processes and waste liquid treatment processes in food factories. Many types of coagulants and filter aids have been proposed so far. Among them, as a method effective for improving the coagulation effect and filtration speed,
A method in which silica sol and chitosan are used in combination has been known (Japanese Patent Application Laid-Open No. H8-322547). Further, a method in which chitosan and sodium alginate are used in combination as a coagulant has also been proposed (JP-A-2-174654).

In these prior arts, when chitosan is used as a filter aid, finely pulverized chitosan is added to the liquid to be treated in powder form. When chitosan is used as a body feed agent, powdery chitosan is used by mixing it into a powder, and when it is used as a precoat agent, filter paper is coated with chitosan powder.

[0004]

On the other hand, chitosan is a material which is difficult to pulverize because it is easily affected by heat. The chitosan powder used in the above-mentioned prior art is pulverized after cooling with, for example, liquid nitrogen at about −20 ° C. to −10 ° C. for 1 to 20 seconds, or a pulverization step requiring an extremely long time. For this reason, chitosan is an extremely expensive material, and at present it has not been sufficiently utilized in this field.

[0005] It is an object of the present invention to provide a simpler and more economical protein in removing protein from a liquid using chitosan, showing a coagulation effect and filtration performance equal to or higher than those of conventionally used chitosan powder. To provide a method for removing carbon dioxide.

[0006]

SUMMARY OF THE INVENTION The present invention is a method for removing a protein from a liquid material containing the protein, comprising using a chitosan-coated material whose surface is coated with chitosan by precipitating chitosan from a chitosan solution. The treatment is carried out by bringing the liquid to be treated into contact with the chitosan coating.

In one preferred embodiment according to the present invention, the protein is aggregated and removed by adding a silica sol and the above-mentioned chitosan coating as an aggregating agent to a liquid material containing the protein.

In another preferred embodiment according to the present invention, a silica sol is added to a liquid material containing a protein to coagulate the protein, and the above-mentioned chitosan-coated material as a body feed agent is added to the coagulated material, followed by mixing. Pressure filtration or centrifugal filtration.

In still another preferred embodiment according to the present invention, a protein is aggregated by adding silica sol to a liquid material containing the protein, and the aggregate is filtered using a filter precoated with the chitosan-coated material. .

The chitosan coating used in the present invention comprises:
Cellulose, silica, wollastonite, activated carbon, diatomaceous earth and other organic or inorganic fibrous, scaly or powdery substance in the presence of a core material, by precipitating chitosan from the chitosan solution, the core material Is a chitosan-coated product in which the surface is coated with chitosan. However, the chitosan coating does not necessarily have to cover the entire surface of the core material, and it is sufficient that chitosan is present at least on a part of the surface. Therefore, a part of the core material is dissolved in the chitosan solution, a part of the core material is precipitated together with the deposition of chitosan, and the state where the chitosan and the core material are mixed on the surface is also the present invention. Can be used as a chitosan coating.

As a specific method for producing a chitosan coating, for example, chitosan is dissolved in an acidic solution such as lactic acid, acetic acid, or citric acid, and a core material such as cellulose is added thereto. A method in which an alkali such as potassium hydroxide is added to form a chitosan coating on the surface of the core material, followed by washing, filtration and drying.
In such a manufacturing method, when a material that partially dissolves in an acidic solution, such as a core material such as cellulose, is used as the core material, a part of the core material is dissolved, and by adding an alkali, the core material is mixed with chitosan. Some precipitate, but as described above, such are also included in the chitosan coating of the present invention.

In addition, chitosan is produced by deacetylating chitin. When a chitosan solution is produced in the production process, a core material is added to the chitosan solution in the production process, and A chitosan coating may be produced by precipitating chitosan in the presence.
Thereby, a chitosan coating can be produced more easily and economically.

The chitosan used in the production of the chitosan coating preferably has a degree of deacetylation of 70% or more, more preferably 85% or more. The chitosan coating amount of the chitosan coating in the present invention,
There is no particular limitation, but usually 5 to 100 parts by weight of the core material.
Those coated at a rate of up to 300 parts by weight are used.

The shape of the chitosan coating in the present invention is preferably about 1 μm to 5 mm in the case of a powdery substance, and about 1 μm to 1 mm in the case of a fibrous substance, and an aspect ratio of about 2 to 100. Is preferred. The shape of these chitosan coatings can be appropriately set by selecting the shape of the core material. Therefore, the particle size, specific gravity, specific surface area and the like of the chitosan coating can be freely adjusted according to the type of the liquid material, whereby the sedimentation speed and the filtration speed of the chitosan coating can be appropriately set. . It is also possible to make a fibrous chitosan-coated product and use it as a filter paper.

In the present invention, when the chitosan-coated material is used as a flocculant by adding it to a liquid material containing a protein, the amount used is usually preferably about 10 to 100 g per kiloliter of the liquid material. When used, it can be used by directly adding it to the liquid to be treated. At that time, the use of silica sol can synergistically improve the aggregation effect.

In the present invention, when the chitosan-coated material is used as a body feed agent, that is, when the protein is aggregated by adding silica sol and the chitosan-coated material is added to and mixed with the aggregate, the amount of the chitosan-coated material used is: It can be determined by converting from the amount used as the flocculant,
10 to 100 g per 1 liter of liquid before aggregation
It is preferable to add such an amount as to obtain the degree.

In the present invention, when the chitosan-coated material is used by pre-coating on a filter, that is, silica sol is added to agglomerate the protein, and when the aggregate is filtered, a filter pre-coated with the chitosan-coated material is used. The amount of the chitosan-coated material used for filtration is preferably 100 g to 2 kg, more preferably 300 g to 800 g, per square meter of the filtration area of the filter.

The silica sol used in the present invention is not particularly limited, and various modified or unmodified silica sols can be used. Usually, silica content 15 ~
About 45% by weight of silica sol is used, and commercially available products are Copolloc 300 and 306 (manufactured by Otsuka Chemical Co., Ltd.
Silica content of 30% by weight) is preferably used.

In the case of silica sol having a silica content of 30% by weight, the amount of the silica sol is usually preferably about 100 to 3000 ml, more preferably 300 to 2 ml per kiloliter of a liquid containing protein.
It is about 000 ml. In the case of a silica sol having a silica content of 20% by weight, 300 to 3000
It is preferable to use about milliliter.

In the present invention, when the chitosan-coated material is used as a coagulant, gelatin, peptides, proteins such as wheat proteins, alginic acid, carrageenan, polysaccharides such as agar, and polyacrylic acid, as long as the effects of the present invention are not impaired. Gelling agents such as acid soda, persimmon juice, tannic acid, PVPP
One or more of adsorbents such as (polyvinylpolypyrrolidone), silica gel, bentonite, acid clay, talc, alum and activated carbon, and filter aids such as cellulose and diatomaceous earth may be used in combination.

In the present invention, when the chitosan-coated material is used for a body feed or a precoat, a filter aid such as diatomaceous earth or cellulose and an adsorbent such as activated carbon may be appropriately mixed and used in addition to the chitosan-coated material. it can.

The method for removing protein of the present invention comprises:
The present invention can be applied to various processes from production of a liquid containing a protein such as wine, beer, vinegar, soy sauce, fish sauce, fruit juice, to raw material adjustment, purification, and waste liquid treatment.

According to the method of the present invention, even in a filtration step involving pressurization and contact with water, destruction of protein flocs is prevented, and good separation and removal of proteins becomes possible. Further, according to the method of the present invention, the use of expensive chitosan can be reduced in a smaller amount, and good coagulation and rapid filtration become possible.

[0024]

Hereinafter, the present invention will be described in more detail with reference to specific examples according to the present invention. However, the present invention is not limited to the following examples.

Preparation Example 1 (Preparation of chitosan coating) 1 g of chitosan and 5% of lactic acid (90% by weight) in 100 ml of water
ml of chitosan to completely dissolve, and cellulose therein (average fiber diameter 0.7 mm, average fiber length 3 mm).
Was added. Next, an aqueous sodium hydroxide solution was added for neutralization, followed by filtration, washing and drying to obtain 2.3 g of a chitosan-coated product (chitosan content: 35% by weight).

Examples 1 and 2 and Comparative Example 1 Activated carbon (trade name "Special Shirasagi" manufactured by Takeda Pharmaceutical Co., Ltd.) was added to sake at a ratio of 500 g / kl.
After stirring, the mixture was transferred to a 100 ml measuring cylinder, and silica sol (trade name “COPOLOC 30” manufactured by Otsuka Chemical Co., Ltd.)
0 ", a silica content of 30% by weight) was added and stirred at a rate of 600 ml / kl, and further, 3 mg of low molecular gelatin (manufactured by Tomiyama," purified gelatin ") was added and stirred. After 24 hours, the supernatant and the origin part were filtered as follows, and the turbidity of the filtrate was measured. The turbidity was measured by Nippon Denshoku Industries Co., Ltd., N
It was measured with a DH-20D turbidimeter.

[0027] The above filtration was performed using Advantech Toyo Co., Ltd. Using a 5A filter paper, the filter paper was pre-coated with 1 g of diatomaceous earth (trade name "Standard Supercell") manufactured by Celite Co., USA, and then precoated with 1 g of the filter paper. Apply the coating to 0.
03 g (Example 1) and 0.1 g (Example 2) were precoated, and the supernatant and the origin portion were suction-filtered using the precoated filter paper, and the turbidity of the filtrate was measured as described above. did.

For comparison, in Comparative Example 1, only the diatomaceous earth was precoated on the filter paper, and the supernatant and the origin portion were similarly suction-filtered using a filter paper not precoated with the chitosan-coated material. Turbidity was measured.

Table 1 shows the results of these measurements.
Turbidity ". Next, add 1 to the remaining paper on the filter paper.
Add 00 ml of water and add 1.0 kgf / m ^TwoUnder pressure
Filtration (water pushing), measure the turbidity of the filtrate at this time
Was. The measurement results are shown in Table 1 as "water turbidity of the filtrate."
You.

[0030]

[Table 1]

As is clear from the results in Table 1, Example 1 was filtered using a filter paper precoated with a chitosan-coated material.
As for Comparative Examples 1 and 2, the turbidity of the supernatant filtrate and the filtrate after water pressing were smaller than those of Comparative Example 1, and it was found that the clarity was significantly improved.

Example 3 Activated carbon similar to that of the above example was added to sake at a rate of 500 g / kl and stirred, then transferred to a 100 ml measuring cylinder, and 0.06 ml of the same silica sol as the above example was added. The same low molecular gelatin as in the above example was
After 24 hours, 0.1 g of the chitosan-coated material prepared in Preparation Example 1 was added and stirred. Using a filter paper obtained by precoating 1 g of the same diatomaceous earth as that of the above-mentioned filter paper on the 5A filter paper, the supernatant and the origin portion were suction-filtered, and the turbidity of the filtrate of the supernatant was measured.

Next, 100 ml of water was added to the remaining orifice portion, and filtered (pressed with water) under pressure in the same manner as in the above embodiment.
The turbidity of the water-pressed filtrate was measured. Table 2 shows the measurement results. Table 2 shows the measurement results of Comparative Example 1 again.

[0034]

[Table 2]

As is evident from the results in Table 2, when the chitosan-coated material was used as a body feed agent, the turbidity of the filtrate was small, and similarly, excellent protein removal performance was exhibited. .

Example 4 Activated carbon similar to that of the above example was added to sake at a rate of 500 g / kl and stirred, then transferred to a 100 ml measuring cylinder, and 0.06 ml of the same silica sol as the above example was added. The same low molecular gelatin as in the above example was
mg of the chitosan coating prepared in Preparation Example 1 above was 0.1
g, add and stir, and after 24 hours,
Suction filtration was performed in the same manner as in Example 3, and the turbidity of the supernatant filtrate was measured. In addition, the turbidity of the filtrate after water pressing was measured for the orifice portion. Table 3 shows the measurement results.

[0037]

[Table 3]

As is evident from the results in Table 3, the use of the chitosan-coated material according to the present invention together with the silica sol as an aggregating agent improves the filtration performance after water pressing.

[0039]

According to the present invention, the protein is removed from the protein-containing liquid using a chitosan-coated material in which the surface of the core material is coated with chitosan. Since such a chitosan coating has a coagulation effect and filtration performance equal to or higher than those of conventionally used chitosan powder, the use of expensive chitosan can be reduced in a smaller amount, and it is simple and economical. Protein can be effectively removed.

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Claims (5)

[Claims] 1. A method for removing a protein from a liquid substance containing a protein, comprising: using a chitosan-coated material whose surface is coated with chitosan by precipitating chitosan from a chitosan-dissolved solution; A method for removing a protein from a liquid material, wherein the method comprises contacting and treating. 2. A method of adding silica sol and chitosan to a protein-containing liquid to remove proteins by coagulation, wherein the chitosan-coated material whose surface is coated with chitosan by precipitating chitosan from a chitosan solution is used as the chitosan. A method for removing a protein from a liquid material, which is used. 3. A method of adding a silica sol to a liquid substance containing a protein to aggregate the protein, and further filtering the aggregate, wherein the chitosan is coated with chitosan by precipitating chitosan from a chitosan solution. A method for removing proteins from a liquid material, comprising adding and mixing the substance to the aggregate, followed by pressure filtration or centrifugal filtration. 4. A method of adding silica sol to a protein-containing liquid to aggregate proteins and filtering the aggregates, wherein chitosan is precipitated from a chitosan solution to coat the surface with chitosan. A method for removing proteins from a liquid material, comprising pre-coating a substance on a filter, and filtering using the pre-coated filter. 5. A chitosan coating is obtained by adding at least one core material selected from cellulose, activated carbon and diatomaceous earth to an acidic aqueous solution in which chitosan is dissolved, and then adding an alkali to precipitate chitosan. The method for removing a protein from a liquid according to any one of claims 1 to 4, which is a chitosan coating obtained.