JPH07310238A - Production of curdlan fiber and curdlan fiber and food - Google Patents

Abstract

PURPOSE:To provide a production method of curdlan fiber suitable for food use, and hardly being putrefied by its suppression against fungal growth. CONSTITUTION:A spinning dope prepared by dissolving curdlan in an aqueous alkaline solution is delivered into a coagulating bath consisting of a nonacidic aqueous solution containing, an alkali (alkaline earth) metal salt as the main ingredient to produce a multifilament yarn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for industrially producing highly productive fibers of curdlan, which is a heat-coagulable polysaccharide mainly composed of .beta.-1,3-glycoside bonds. More specifically, the present invention relates to a method for producing curdlan fiber suitable for food use, in which generation of mold is suppressed and which is resistant to decay.

[0002]

2. Description of the Related Art Various methods have been proposed for obtaining curdlan moldings. For example, Japanese Patent Publication Sho 48-448
Japanese Patent Laid-Open No. 65-65 discloses a method of dissolving curdlan in an aqueous solution of a soluble substance such as sodium hydroxide or potassium hydroxide, reducing the amount of the soluble substance from the obtained solution to cause gelation, and molding. There is. In Japanese Patent Publication No. 62-29527, the curdlan is dissolved in an alkaline aqueous solution, and the resulting solution is discharged into a coagulation bath containing 1 to 5N sulfuric acid or hydrochloric acid mixed with alcohol, and the fiber is discharged. A method of manufacturing is disclosed. Furthermore, in Japanese Patent Laid-Open No. 2-111520,
The curdlan water suspension is extruded into a thin film and heated and solidified.
A method for obtaining a curdlan film by drying is disclosed, and in Japanese Patent Laid-Open No. 3-157401, the same idea is applied to fiberization, and an aqueous suspension of curdlan is heated to 85 ° C. or higher. A method of gelling and threading is disclosed.

However, the method described in Japanese Patent Publication No. 48-44865 uses a dialysis membrane to reduce the soluble substance from the aqueous solution of the soluble substance of curdlan.
It was not desirable from a practical standpoint. More importantly, as a result of a detailed study by the present inventors, it was found that the curdlan fiber produced by these methods easily molds when stored and is easily decomposed. . Therefore, the curdlan fibers produced by these methods were not suitable as food grade fibers.

On the other hand, Japanese Examined Patent Publication No. 52-43840 discloses that curdlan produced by bacteria is dissolved in caustic alkali, and an alkaline earth metal salt or an alkali metal salt is added to this solution to obtain the viscosity of the solution. However, no attempt has been made to fibrate curdlan with an alkaline earth metal salt or an alkali metal salt, and a method for removing insoluble impurities has been disclosed. There is no known literature to suggest.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for industrially producing curdlan fiber which is suitable for foods, in which generation of mold is suppressed and is resistant to putrefaction, with high productivity. This is an issue.

[0006]

Means for Solving the Problems As a result of intensive studies in view of the above circumstances, the present inventors have dissolved curdlan in an alkaline aqueous solution and used an alkaline earth metal salt or an alkali metal salt as a main component as a coagulating liquid. The present invention was found by the fact that the spinning of a non-acidic aqueous solution improves the physical properties of the obtained fiber, and that the obtained fiber has the characteristics that mold generation is suppressed and it is difficult to rot. .

That is, according to the present invention, a spinning dope prepared by dissolving curdlan in an alkaline aqueous solution is discharged into a coagulating bath made of a non-acidic aqueous solution containing an alkaline earth metal salt or an alkaline metal salt as a main component. The gist is a method for producing a curdlan fiber, which is characterized in that a yarn is formed.

The present invention will be described in detail below.

The curdlan used in the present invention is β-1.
It is a general term for heat-coagulable polysaccharides mainly composed of 3-glycoside bonds, and includes those produced by microorganisms such as those belonging to the genus Alcaligenes or the genus Agrobacterium.

It is necessary to use an alkaline aqueous solution as a solvent for dissolving curdlan, and a neutral aqueous solution, an acidic aqueous solution, or an organic solvent cannot achieve the object of the present invention. As the alkaline component, sodium hydroxide, potassium hydroxide and lithium hydroxide are preferable.

The alkaline concentration of the alkaline aqueous solution for dissolving the curdlan is not particularly limited, but is 0.01 to 2
It is preferable to specify it. When the alkali concentration is lower than 0.01 standard, it is difficult to obtain a fiber having uniform and good physical properties, while when it is higher than 2 standard, the solution is easily colored when the curdlan is dissolved.

The concentration of curdlan in the spinning dope is 0.1 to 20.
It is preferable to set it as a weight% and more preferably 1 to 12 weight%. If the concentration of curdlan is lower than 0.1% by weight, the spinnability is deteriorated, while if it is higher than 20% by weight, the curdlan becomes difficult to dissolve. In the present invention, it is preferable to dissolve the curdlan and then degas the solution by placing it in a reduced pressure state, and a defoaming agent may be used if necessary. Further, the temperature of the tank for storing the spinning dope is preferably below the transition temperature at which gelation starts, that is, below 45 ° C. If the temperature of the tank exceeds 45 ℃, gelation will start in the tank and it will be difficult to perform constant-quantity discharge and spinning.

The spinning dope thus prepared (alkaline aqueous solution of curdlan) is discharged into a coagulation bath to obtain the curdlan fiber of the present invention. The spinning method is dry-wet spinning method,
Although any of the wet spinning methods may be used, the wet spinning method is preferable, and the number of holes in the spinneret may be single or plural.

As a coagulating liquid, it is extremely important to use a non-acidic aqueous solution containing an alkaline earth metal salt or an alkali metal salt as a main component, and an acidic aqueous solution or a method using hot water is used in the present invention. The purpose is not achieved. Examples of the alkaline earth metal salt or alkali metal salt used in the present invention include calcium chloride, sodium chloride, sodium sulfate, sodium carbonate, and the like.
Calcium chloride is particularly preferred.

The concentration of the alkaline earth metal salt or the alkali metal salt in the coagulation liquid is not particularly limited,
It is preferable to set 0.01 to 5.0. In the present invention, lower alcohols such as ethanol and methanol may be added to such a coagulating liquid, which makes the yarn strong by the dehydration action of alcohol and prevents yarn breakage during spinning. preferable.

In the present invention, it is preferable that the yarn solidified and solidified in the coagulation bath is further neutralized with an acidic aqueous solution and then repeatedly washed with water to remove the alkali component and the acid component. The acid used for neutralization is preferably hydrochloric acid or sulfuric acid from the viewpoint of workability and neutralization rate.

The state of the curdlan fiber obtained in the present invention is not particularly limited, and may be wet curdlan fiber containing water or dry curdlan fiber containing no water. When the wet curdlan fiber is used, it can be easily obtained by washing with water, draining it with a wire net, etc., and dehydrating it. Further, when the dried curdlan fiber is used, the wet curdlan fiber may be dried. At the time of drying, it is preferable to add an oil agent prior to the drying treatment, because it is possible to prevent the fibers from sticking or sticking together.

As a drying method, a method of drying in a heated gas, a method of contacting with a heating body and drying, or the like can be adopted. Furthermore, the dried curdlan fiber obtained in the present invention can be made into a wet curdlan fiber again by immersing it in water or hot water. It is possible to return to.

In the present invention, the form of the final curdlan fiber is not particularly limited, either, continuous fibers having a substantially infinite length, short fibers cut to a desired length, or even random fibers. It can be short fibers of length. To make continuous fibers, take the fibers from the coagulation bath with a roll, etc., as is done in normal fiber manufacturing processes.
Further, it may be passed through a neutralizing bath, a washing bath, a heat treatment bath, or the like.
Further, the fibers in the coagulation bath may be received in a web form by a belt conveyor or the like, and the web form may be subjected to neutralization, water washing, heat treatment and the like. Short fibers can be produced by cutting continuous fibers by a conventional method.

The curdlan fiber obtained by the present invention is characterized in that generation of mold is suppressed and it is difficult to rot.
It can be used as a quality improver that is added to existing foods in small amounts, or can be used as a food ingredient to make new foods.

[0021]

In the present invention, the reason why the curdlan fiber having excellent performance can be obtained is not clear, but by using an alkaline earth metal salt or an aqueous solution of an alkali metal salt as a coagulating liquid, the cation component of the dissociated salt is obtained. It acts as a cross-linking agent for curdlan, and it is considered that cross-linking points are formed by ionic bonds and gel.

[0022]

EXAMPLES Next, the present invention will be specifically described by way of examples.

Example 1 A 0.3% aqueous sodium hydroxide solution having a concentration of 10% by weight
The curdlan was dissolved so that it became, and then defoamed under reduced pressure to prepare a spinning dope. This spinning solution was added with a pore size of 0.3 mm,
From a spinneret with 300 holes, containing 1% by weight of ethanol
Wet spinning was carried out in a coagulation bath consisting of a 2.0 N aqueous solution of calcium chloride to obtain a solidified yarn. This solidified yarn is neutralized by introducing it into a 0.3 N hydrochloric acid aqueous solution, and then washed twice in a washing bath, then heat-treated in boiling water for 1 minute, and water is separated with a wire mesh to obtain wet curdlan fiber. Obtained. The curdlan fiber was stored in a wet state at room temperature for 4 weeks, but no generation of mold or decay was observed.

Comparative Example 1 Wet spinning and post-treatment were carried out in the same manner as in Example 1 except that a 0.3N aqueous sulfuric acid solution was used as the coagulating bath to obtain a wet curdlan fiber. When the obtained fiber was stored in a wet state at room temperature, mold developed after only 2 days and putrefaction started after 3 days.

Example 2 Curdlan was dissolved in a 0.1N aqueous lithium hydroxide solution to a concentration of 2% by weight, and then defoamed under reduced pressure to prepare a spinning dope. This spinning dope was dry-wet spun from a spinneret having a hole diameter of 0.3 mm and a number of holes of 150 into a coagulation bath consisting of a 4.0 N sodium carbonate aqueous solution, and fully coagulated to obtain a solidified yarn. This solidified yarn is neutralized by introducing it into a 0.1 N sulfuric acid aqueous solution, and then washed twice with a washing bath, and then at 90 ° C.
The dried curdlan fiber was obtained by drying with a heating drum.

The dried curdlan fiber was stored at room temperature for half a year, but no generation of mold or decay was observed. Further, the dried curdlan fiber was dipped in tap water to obtain wet curdlan fiber again, and the curdlan fiber was stored in a wet state for 3 weeks, but no generation of mold or decay was observed.

Example 3 A 0.3% aqueous sodium hydroxide solution having a concentration of 10% by weight
The curdlan was dissolved so that it became, and then defoamed under reduced pressure to prepare a spinning dope. This spinning dope was wet spun from a 20 mm x 2 mm square spinneret into a coagulation bath consisting of a 2.0 N calcium chloride aqueous solution containing 1% by weight of ethanol to obtain a solidified yarn. This solidified yarn is neutralized by introducing it into a 0.3 N hydrochloric acid aqueous solution, and then washed twice with a washing bath, followed by heat treatment for 1 minute in a boiling aqueous solution containing orange extract, and separating the water with a wire mesh. To obtain a wet curdlan plate-like fiber. This plate-shaped fiber was cut into a length of 50 mm to produce a food with an orange scent.
The texture was also good.

[0028]

According to the present invention, curdlan is dissolved in an alkaline aqueous solution and an alkaline earth metal salt,
Alternatively, by spinning using a non-acidic aqueous solution containing an alkali metal salt as a main component, it becomes possible to easily produce curdlan fiber, which has been difficult in the past, so that the productivity is dramatically improved. The use of curdlan fiber as a food fiber is expected to expand. Further, the curdlan fiber obtained in the present invention is advantageous as a fiber for food since it has features that mold generation is suppressed and it is difficult to rot.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoji Ichinose 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Ltd. Central Research Laboratory

Claims (4)

[Claims] 1. A yarn is formed by discharging a spinning dope prepared by dissolving curdlan in an alkaline aqueous solution into a coagulation bath composed of an alkaline earth metal salt or a non-acidic aqueous solution containing an alkali metal salt as a main component. A method for producing a curdlan fiber, which comprises: 2. The method for producing curdlan fiber according to claim 1, wherein the alkaline earth metal salt is calcium chloride. 3. A curdlan fiber obtained by the manufacturing method according to claim 1. 4. A food containing the curdlan fiber according to claim 3.