JPS605257B2 - Method for producing edible fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing edible fiber of constant quality, physical properties, and fiber diameter in a short time from a protein whose main component is soybean protein.

Conventionally, when producing edible fiber using the graded yarn method using soybean protein as a raw material, protein paste or separated protein powder obtained from defatted soybeans by a conventional method is mixed with sodium hydroxide,
A solution with a protein concentration of 11.0 to 13.0% by weight and a pH of 12.0 or higher is prepared by dissolving it using an alkaline aqueous solution such as potassium hydroxide, and this alkaline solution is allowed to age and when spinnability is developed, spinning is carried out. to obtain edible fiber.

The time required for this stringiness to develop depends on the protein concentration,
Although it varies depending on aging temperature, soybean protein alkaline solution immediately after dissolution usually has a high viscosity and is extremely elastic and gel-like, and the viscosity decreases over time until it becomes stringable. It takes about 1 hour.

On the other hand, it has recently been pointed out that the pH of the soybean protein alkaline solution prepared in this manner is extremely high, and thus the protein is hydrolyzed by alkali, resulting in the production of harmful substances such as lysinoalanine.

It is known that harmful substances such as lysinoalanine are more likely to be produced as the pH is higher, the aging time is longer, and the aging temperature is higher. If the pH is lowered, the higher-order structure of the protein is not fully resolved, resulting in a solution with poor stringability. Therefore, in order to suppress the production of harmful substances such as lysinoalanine, it is necessary to shorten the aging time as much as possible, and desirably complete fiberization within one hour. However, as is already known, the viscosity of the soybean protein alkaline solution decreases over time, and the decrease in viscosity is particularly remarkable in the first hour after being dissolved in the alkali.

For this reason, the viscosity of the alkaline solution of soybean protein dissolved in alkali varies widely, and it is extremely difficult to control the viscosity, not only when producing edible fiber in a batch process, but also when producing edible fiber continuously. be. If there are variations in the viscosity of the alkaline solution of soybean protein dissolved in alkali, the spinnability of the solution will change, and if the spinnability is lost, it will be difficult to form paper threads or the threads will break during the drawing process. Furthermore, even if the yarn quality is good, the fiber diameter may change or the physical properties of the fiber may change, making it impossible to obtain edible fiber of a constant quality.
Moreover, it becomes difficult to transport through a pipe due to gelation immediately after dissolution. This has traditionally been a major obstacle in producing edible fiber from soybean protein. The present invention eliminates the drawbacks of the conventional method as described above, and reduces the viscosity of a solution containing soybean protein as a main component dissolved in an alkali.
It is possible to produce edible fiber with constant quality, physical properties, and fiber diameter in a short time by controlling the edible fiber within the range of ~40 poise and almost constant. Add an appropriate amount of S-S bond cleavage agent to the aqueous dispersion, add alkali to dissolve the protein, and adjust the viscosity to 5-40.
This is a method for producing edible fibers, which is characterized by obtaining a solution whose poise is within a substantially constant range and forming the solution into fibers within a short time.

In the present invention, the protein whose main component is soybean protein is
It refers to soybean protein alone or to soybean protein with up to 20% of casein, skim milk powder, whey liquid, starch, etc. added.

The soybean protein may be any protein separated from soybeans, and protein paste or isolated protein powder obtained from defatted soybeans by a conventional method is usually used. In the present invention, when an alkali such as sodium hydroxide or potassium hydroxide is added to an aqueous dispersion of a protein mainly composed of soybean protein to dissolve the protein, an S-S bond cleaving agent such as L-cysteine or sulfite is used. Small amounts of sodium, potassium sulfite, and mercaptoethanol are added.

By doing so, a solution with a substantially constant viscosity within the range of 5 to 40 poise can be obtained. The present inventors believe that the change in the viscosity of the soybean protein alkaline solution over time is mainly due to the cleavage of the S-S bonds contained in the soybean protein by alkali. As a result of research on the relationship between S-S bonds and viscosity, it was found that when a certain amount of L-cysteine, an S-S bond cleavage agent, and sodium sulfite are added to an aqueous dispersion of soybean protein and dissolved in an alkali, the viscosity of the solution changes over time. It was found that the amount increased in contrast to when no additive was added.

For example, in an aqueous dispersion of soybean protein, 20 mmol/1 protein
A soybean protein alkaline solution with a concentration of 13.5% (pH
120) aged at 300C, 2.
5 poise, 5 poise in 30 minutes, 10 poise in 1 hour...
1. 16 poise in insect time, 24 poise in 2.5 hours, 3
．． It was found that the viscosity of the soybean protein alkaline solution increased over time, such as 32 poise in 4.5 hours and 39 poise in 4.5 hours. From this, it was found that by adding an appropriate amount of an S-S bond cleaving agent, the S-S bond of soybean protein was
They found that if the bonds were broken appropriately, the viscosity of the alkaline solution could be controlled to be almost constant. S-
The appropriate amount of the S-bond cleaving agent varies depending on the type; for example, in the case of L-cysteine, it is preferably 0.3 to 3.0 mmol/100 mmol of protein.
100 mmol of protein and 5.0 to 50 mmol/10 mmol of protein in the case of sodium sulfite or potassium sulfite.
0, preferably 10.0 to 30.0 mmol/100 mmol of protein, and in the case of mercaptoethanol 0.4
~4.0 mmol protein 100 mg.

The viscosity of the protein alkaline solution containing soybean protein as the main component prepared in this way is within the range of 5 to 40 poise, and the difference in viscosity immediately after and 1 hour after being dissolved in the alkali is within 10 poise at most. It becomes possible to make it almost constant.

An experimental example regarding this point is as follows. Experimental Example 1 A protein paste (protein concentration 21.35%) obtained from defatted soybean flakes by a conventional method was added at 550.4 pm to disperse 346 ml of water. .142 hours was added.

Separately, a solution of 9.4 ml of sodium hydroxide dissolved in 94 ml of water was added to the above protein dispersion to give a final protein concentration of 11.
Soybean protein alkaline solution 75% by weight, pH 12.1, cysteine concentration 1.0 mmol/protein 100 lkg
adjusted. The viscosity change over time of this alkaline solution is as follows: At the aging temperature of 30°C, the viscosity after 1 minute of alkali dissolution is approximately 24 poise, and the viscosity 15 minutes after alkali dissolution is approximately 27 poise, 1
The viscosity after hours was about 30 poise. Experimental Example 2 Separated protein powder (protein concentration 84.77%) obtained by freeze-drying soybean protein paste (protein concentration 84.77%) was mixed with 132.7% of water and 756% of water.
After adding and dispersing No. 7 and maintaining the concentration at 30 mm, 1.42 mm of sodium sulfite was added.

On the other hand, a solution of 9.0 g of sodium hydroxide dissolved in 100 g of water was added to the above protein dispersion to obtain a final protein concentration of 1.
1.25% by weight, pH 12.1, sodium sulfite 10
Soybean protein alkaline solution 1 mmol/100 protein
kg was adjusted. The viscosity change of this alkaline solution over time was as follows: At an aging temperature of 3000, the viscosity was about 18 poise after 1 minute of alkali dissolution, the viscosity 15 minutes after alkali dissolution was about 22 poise, and the viscosity after 1 hour was about 20 poise. As mentioned above, the viscosity of the soybean protein alkaline solution prepared by the conventional method without the addition of an S-S bond cleavage agent is extremely high immediately after dissolution;
It takes about 1 hour for aging to develop stringiness, and the rate of change in viscosity is large even after aging.

For example, protein concentration 11.25% by weight, aging temperature 30CC
Then, immediately after dissolution, it is about 100 poise, and the stringiness is expressed.
After hours, it is about 30 poise. Therefore, the nearly constant viscosity of the alkaline protein solution in the present invention described above is advantageous in producing edible fibers with constant quality, physical properties, and fiber diameter by shortening the aging time as much as possible. It is easy to transport in pipes, and is very easy to operate and effective, especially when performing continuous melt spinning.

Next, the alkaline protein solution obtained as described above is made into fibers.

That is, this solution is maintained at an aging temperature of 20 to 50 oo, and when it ages and becomes spinnable, it is spun to obtain edible fibers. In this case, in the present invention, since the viscosity of the alkaline protein solution is kept substantially constant within the range of 5 to 40 poise, it is possible to form fibers within a short time, for example, within one hour. That is, the twill can be made as short as possible even after the aging time, for example, within 5 minutes.
This weaving can be carried out by any suitable means, for example, the aged solution may be extruded through a nozzle into a coagulation matrix (spinning matrix) and coagulated, or the solution may be extruded into the air through a nozzle and coagulated (spinning matrix) It may also be coagulated by flowing down together with the threads (the latter is more effective). The coagulated fibers are neutralized, washed with water, and dehydrated to obtain edible fibers. These steps can be performed either batchwise or continuously. Thus, according to the present invention, the viscosity of an alkaline solution of a protein containing soybean protein as a main component is kept almost constant within the range of 5 to 40 poise, thereby producing edible fiber with constant quality, physical properties, and fiber diameter. This is a very advantageous method for producing edible fibers.

Next, examples of the present invention will be shown.

Example 1 Add 200ml of water to 24kg of low-denatured defatted soybeans, extract the protein according to a conventional method, remove impurities, add hydrochloric acid to adjust the pH to 4.6, and prepare 30kg of protein paste (protein concentration 25%). Obtained.

To this paste, 28.6 mm of water was added, and while maintaining the paste at 30 mm, L cysteine of 9 mm was added. Next, 10% sodium hydroxide solution was added for 6 hours to bring the protein concentration to 11.5%.
, cysteine concentration 1.0 mmol/100 mmol protein, p
H12.1 spinning dope (viscosity 20 poise) 65.2k9
I got it. The viscosity of this stock solution after being held at 3030 for 5 minutes was approximately 20 poise. This spinning stock solution was extruded through a 0.1 willow nozzle into a paper yarn made of salt and hydrochloric acid for 300 minutes.
%, further neutralized using sodium hydroxide and salt, washed with water and dehydrated according to conventional methods to obtain fibers with a moisture content of approximately 65%.
0.2 kg was obtained.

The tensile strength of this fiber is 5.3×1 dynes/me,
It was soft and very good as a raw material for processed meat products.

Example 2 To 30k9 of protein paste obtained in the same manner as in Example 1, 31.4ml of water and 180ml of sodium sulfite were added.
000 and added 10% sodium hydroxide solution to obtain a spinning stock solution (viscosity 10 poise) 68.2k9 with a protein concentration of 11.0%, pH of 12.2, and a sodium sulfite concentration of 20 mmol/100 mmol of protein. .

After keeping this stock solution at 30oo for 5 minutes, the viscosity is about 12
It was Poise. This spinning dope is extruded into the air through a five-sided nozzle, coagulated by flowing down together with a coagulant consisting of common salt and hydrochloric acid, and further neutralized with acetic acid and sodium acetate. Approximately 71% fiber 23.4k9 was obtained.

The tensile strength of this fiber is 1.8×1 pidane/me,
It had a great sense of flesh. Example 3 In the same manner as in Example 1, 20 grams of water and 18 grams of L-cysteine were added to soybean protein paste 30k9 and maintained at 30:00.

On the other hand, milk casein 1.9k9 was dispersed in water 19.3ml,
3000 was mixed with the above soybean protein dispersion, and 7.5% of 10% sodium hydroxide solution was added to give a total protein concentration of 13.5%, pH of 12.1, and cysteine concentration of 1.6 mmol/100 of protein. A soybean protein-casein mixed grade yarn stock solution (viscosity 12 poise) of 69.4k9 was also obtained. The viscosity of this stock solution after being held at 3000 for 5 minutes was about 15 poise. This was then subjected to fiberization in the same manner as in Example 2 to obtain fiber 28.3k9 with a water content of about 68%.

Claims (1)

[Claims] 1 S-
It is characterized by adding an appropriate amount of an S-bond cleaving agent and adding an alkali to dissolve the protein to obtain a solution whose viscosity is approximately constant within the range of 5 to 40 poise, which is then turned into fibers within a short time. A method for producing edible fiber.