JPH07285995A - Treatment of protein-containing aqueous solution - Google Patents

Abstract

PURPOSE:To improve the quality of an animal and vegetable extract, a vegetable juice and an animal and vegetable waste liquid and improve the efficiency of treatment of the waste liquid. CONSTITUTION:Protein components contained in an extract, a juice and a waste liquid are converted into a cross-licked polymer by an action of transglutaminase and flocculated. Its separability is improved thereby in separation and removal by filtration, centrifugal separation, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating protein-containing aqueous solutions such as animal and plant extracts and animal and plant waste liquors by improving the separability of the proteins by the action of transglutaminase.

The industrial significance brought about by such improvement in separability is extremely great, as will be described later.

[0003]

2. Description of the Related Art Generally, protein-containing aqueous solutions such as bleaching water and animal and plant waste liquor during the production of yeast extract and other food extracts such as animal and plant extracts and fish meat surimi are used for the purpose of quality improvement, wastewater treatment, etc. From
Although the industrially advantageous specific removal of the dissolved protein is desired, there is no method for improving the separability of the dissolved protein suitable for a simple separation method such as filtration and centrifugation.

In addition, salting out, membrane treatment and oxygen decomposition are known as methods for specifically removing such proteins. There is a problem that it has an influence, and this improvement is a problem in industrialization.

[0005]

Under the background of the prior art described in the preceding paragraph, the present invention provides a method capable of specifically separating a dissolved protein from a protein-containing aqueous solution by a simple separation means such as filtration or centrifugation. The purpose is to develop and provide.

[0006]

Means for Solving the Problems As a result of intensive research to achieve the object described in the preceding paragraph, the present inventor has found that proteins dissolved in animal and plant extracts, animal and plant waste liquids, etc. as described above are separable by the action of transglutaminase. The present invention has been completed based on such findings.

That is, the present invention relates to a method for treating a protein-containing aqueous solution, characterized in that transglutaminase is allowed to act on a protein-containing aqueous solution to improve the separability of the protein, and then the protein is separated.

The protein-containing aqueous solution to which the present invention is applied includes, as mentioned above, yeast extract and other animal and plant extracts, bleaching water and other animal and plant waste liquors produced during production of fish meat surimi, and further apple and other. For example, plant juices such as fruit juices, etc., which are desired to specifically remove dissolved proteins for the purpose of quality improvement, wastewater treatment, etc., are widely included.

The transglutaminase (hereinafter sometimes abbreviated as TGase) used in the present invention may have any origin regardless of its origin, for example, isolated from the liver of guinea pig (hereinafter abbreviated as MTGase). For example, those produced by the microorganism disclosed in JP-A-1-27471 (hereinafter abbreviated as BTGase), and natural products such as water extracts of vegetables, fruits, etc., extracts of aquatic products such as fish, and The thing contained in a washing | cleaning liquid etc. can be mentioned. Incidentally, various enzyme preparations of TGase are already on the market, and it is needless to say that the TGase used in the present invention may be in the form of such an enzyme preparation unless there is a particular problem.

When TGase is allowed to act on a protein-containing aqueous solution, the amount of TGase used is, in essence, the amount at which the separability is improved when the protein is subjected to a simple separation method such as filtration or centrifugation. And also p
Conditions such as H, temperature, and time are also those in which the enzymatic action of TGase is expressed, and the protein also shows improved separability. Those skilled in the art can consider such conditions in consideration of the optimal conditions under which the already-known enzyme action of TGase is expressed, and by referring to the examples described later. It can be determined by a simple preliminary trial according to

An appropriate amount of TGas determined in this way
By adding e to the protein-containing aqueous solution to be treated whose pH is adjusted to an appropriate range as necessary and maintaining this at an appropriate temperature for an appropriate period of time, it is considered that the separated protein has improved separability. It will be.

The protein-containing aqueous solution that has undergone such treatment is separated from the dissolved protein by a simple separation means such as filtration or centrifugation.

The treatment of yeast extract, bleaching water of fish meat and fruit juice according to the embodiment of the present invention will be described below.

As is well known, the yeast extract is a concentrated yeast cell component extract derived from a yeast self-digestion solution or mechanically crushed bacterial cells, and the concentrate is also in the form of a dried powder. It is commercially available and is used as a seasoning (material) and a raw material for culturing microorganisms. Needless to say, in order to carry out the present invention with respect to the powdery yeast extract, water may be added to the powdery yeast extract in advance to reduce it into a liquid yeast extract. The yeast extract targeted by the present invention is not particularly limited except that it has a unique yeast odor, and any yeast extract is targeted.

Although yeast extract has a strong taste as a seasoning ingredient, it has a strong yeast odor according to the conventional production method, and therefore, its type and amount to be used in foods are limited. It is restricted.

Deodorization using an adsorbent such as activated carbon has been carried out as a method of removing the yeast odor, which is a restriction on the use of yeast extract in foods. However, when the activated carbon is removed after the deodorization, there is a problem of difficulty in filtration which seems to be caused by the protein component.

As a method for producing a yeast extract using an enzyme preparation, there is already an example in which filterability is improved for the purpose of removing a lipid component liberated during hydrolysis by enzyme treatment ( Japanese Patent Publication No. 20225).

On the other hand, in order to improve the difficulty of filtration, the present inventor paid particular attention to the protein component among the proteins and other colloids generally known as filtration inhibitors, and found the above problems. As a result of various studies to solve the problem, first, TGase was added to the yeast extract to cause it to act to aggregate the protein component, and then deodorization treatment with activated carbon was performed, and this was removed together with activated carbon by filtration, centrifugation, etc. The present invention, which is a method, has been completed.

The TGase treatment of the odorous yeast extract can be performed by the method of the present invention described above. The activated carbon treatment can be based on a general deodorizing treatment method using activated carbon.

According to the present invention, the odorous yeast extract is TGa.
Although it can be subjected to both the enzymatic treatment and the activated carbon treatment of se, the order of the both treatments is not limited as long as the deodorizing effect and the filterability or centrifugal separability improving effect are exhibited. However, from the viewpoint of effective utilization of TGase, it is preferable to precede the enzyme treatment because the loss of TGase due to adsorption of activated carbon can be prevented.

The yeast extract after such treatment is
Dissolved proteins are separated and removed by filtration or centrifugation. According to the present invention, the separation and removal of the dissolved protein can be significantly facilitated as compared with the case where the TGase treatment is not performed.

In addition, the yeast extract from which proteins have been removed by the action of TGase, generally a food extract, has a good taste and is excellent in umami and hydrophobic as compared with products using other enzyme preparations such as protease. Good quality such as no bitterness due to release of soluble amino acids. According to the present invention, a good quality food extract that can be used as a natural seasoning material can be easily produced.

[0023] Generally, the treated waste liquid of animals and plants containing animals and plants such as meat and fish which contains protein has a high BOD due to the contained protein, and if it is discharged to the river as it is, it causes environmental pollution. It is necessary to reduce BOD by subjecting it to treatment or the like. However,
This time, the treatment load of this activated sludge treatment is increased, and the treatment efficiency of the activated sludge is impaired.

For example, the protein contained in the bleached water during the production of fish meat surimi increases the BOD in the waste liquid and deteriorates the treatment efficiency of the activated sludge method and the like.

Since such TGase treatment of bleaching water is directly included in the TGase treatment of the present invention described above, there is no additional point.

According to the present invention using TGase, the protein component of animal and plant waste liquor can be specifically removed, and BOD can be effectively and easily reduced. Compared with, the waste liquid treatment can be performed more effectively and easily in terms of equipment and cost for pretreatment of the sludge sludge method.

According to the present invention, proteins can be effectively and easily removed from plant juice such as apple juice and other fruit juices, and the quality of the plant juice can be improved and the waste solution of the plant juice can be advantageously treated. be able to.

The TGase treatment for carrying out the method of the present invention on plant juice is also performed by the TGas of the present invention described above.
However, in this case, fragrance components other than the protein to be removed are likely to be impaired. Therefore, TGase treatment should be carried out under conditions that do not cause this, for example, at the lowest possible temperature. In many cases, it is necessary to appropriately suppress the occurrence of side effects.

[0029]

As is well known, transglutaminase is an enzyme that catalyzes the acyl transfer reaction of the γ-carboxamide group of the glutamine residue in the peptide chain, and acts as an acyl acceptor of the lysine residue ε-in the protein. When an amino group acts, ε- (γ-Glu)-
Lys crosslinks are formed (see Japanese Patent Laid-Open No. 1-2747).
1).

It is considered that the improvement of the separability of the protein in the present invention is due to the fact that it is intermolecularly crosslinked by the enzymatic action of transglutaminase to be polymerized and aggregated.

[0031]

EXAMPLES The present invention will be further described below with reference to examples.

Example 1 (Improving quality of yeast extract) Water was added to a yeast extract having a yeasty odor so that the solid content was 25% by weight based on the total amount. Then, 0.1% by weight (additional amount) of BTGase (specific activity of 1,000 units / g) was added to the total amount, and the pH was adjusted to 4.5 with hydrochloric acid, and 50
The mixture was stirred at 0 ° C. for 4 hours for enzyme action. Thereafter, activated carbon was added in an amount of 10% by weight (on top) to the whole, and the mixture was stirred at 40 ° C. for 1 hour to deodorize and then filtered. By this filtration, the protein component aggregated with the activated carbon was also removed.

In this case, the filtration speed was remarkably reduced to 1/10 of the time required for filtration as compared with the case where the TGase treatment was not performed in exactly the same manner. Further, the yeast extract in the filtrate can be directly used as a product of good quality yeast extract, or can be dried by a method such as spray drying to give a product of powder extract.

As described above, when the yeast extract is deodorized by the method of the present invention, the filtration efficiency of the filtration treatment included in the deodorization step is remarkably improved, and the unique yeast odor is deodorized. The yeast extract has a favorable taste, and has excellent properties as a versatile natural seasoning material.

Example 2 (Wastewater Treatment of Bleaching Water) The bleaching water (waste fluid) containing a solid content of protein of about 2%, which was prepared by treating the fish meat surimi of Alaska pollack, was put in a 100 kL dose tank at 80% by volume, and the total amount was 0.1% (additional) BTGase (specific activity 1,000 units / g)
Was added, and the mixture was stirred for 12 hours for enzymatic action. During this period, the product temperature was 5 to 40 ° C. Then, the exposed water was subjected to filter filtration to remove the agglomerated protein.

The waste liquid treated in this way is
The OD and protein content were dramatically reduced compared to the waste liquid that was not subjected to such treatment (BOD was 1
(Reduced to 1/0), and the subsequent treatment efficiency by the activated sludge method was improved accordingly.

[0037]

EFFECTS OF THE INVENTION According to the present invention, it is possible to more easily deodorize an odorous extract such as yeast extract by treatment with activated carbon, and thus to improve the quality of the odorous extract more easily. In addition, it becomes easy to remove proteins dissolved in general animal and plant food extracts and other plant juices, and in turn, the quality of these can be improved more easily. The BOD based on the protein inside can be lowered more easily, and by extension, such waste liquid treatment can be performed more easily.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 1/28 D 1/56 C C07K 1/14 8318-4H 14/435 8318-4H (72) Inventor Makoto Sato 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc. Food Research Institute (72) Inventor Haruki Omura 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc. Foods Inside the research institute

Claims (3)

[Claims] 1. A method for treating a protein-containing aqueous solution, which comprises allowing transglutaminase to act on a protein-containing aqueous solution to improve the separability of the protein, and then separating the protein. 2. A method for producing a deodorized yeast extract, which comprises subjecting a yeast extract having a yeast odor to a transglutaminase treatment and an activated carbon treatment, and then filtering or centrifuging. 3. A deodorized yeast extract produced by the method according to claim 2.