JPH0367595A - Production of water-soluble polysaccharide - Google Patents

Abstract

PURPOSE:To obtain, in high yield, the title polysaccharides which are useful in beverage and foodstuffs as a functional food products, because of their excellent taste, texture, especially feeling when it passes through the throat by atomizing water-insoluble dietary fibers and hydrolyzing the protein and the fibers. CONSTITUTION:Water-insoluble plant fibers are atomized, the protein in the fibers are hydrolyzed, then the fibers are hydrolyzed, then the water-soluble polysaccharides are fractionated to obtain the subject polysaccharides. The atomization is preferably carried out by using shearing stress in an aqueous medium, for example, treating with a homogenizer at a pressure of 150kg/cm<2>. The fiber is, e.g. lees of soybean curd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing water-soluble polysaccharides from water-insoluble plant fibers.

(Prior Art) In recent years, there has been increasing interest in dietary fiber, which is one of the functional foods. Dietary fibers are diverse, ranging from plant fiber components (category 11, fiber components of vegetables, fruits, etc.) to synthetic ones such as polydextrose.

The former mainly consists of water-insoluble fibers such as cellulose, hexacellulose, and lignin, and is used as a variety of food materials, while the latter is a water-soluble polysaccharide and is mainly used as beverages.

By the way, water-soluble polyI! is extracted from water-insoluble plant fibers! !
For example, strong alkali.

There is also a method of decomposition using (NaOH solution, etc.), but most of them are decomposed to single trills, making it difficult to obtain water-soluble poly-Ii in high yield.

(Problem to be solved) If plant fibers, which are water-insoluble fibers, can be made water-soluble, the range of industrial applications will expand, including a wider range of uses.

Therefore, the present inventors conducted research aimed at making water-insoluble plant fibers water-soluble. However, the problem with plant fibers is that the fibers are intricately intertwined with proteins, etc., making them difficult to break down and not easily water-solubilized.Additionally, if severe decomposition is performed, they will be broken down into monosaccharides, making it difficult to achieve the desired water-solubility. Nota I
We encountered problems such as a decrease in the yield of type i.

The present inventors solved the above problem and efficiently produced water-soluble multi-IJ from insoluble plant fibers! In order to obtain the same, we conducted research to efficiently obtain water-soluble poly-Ii from okara, which is obtained after producing tofu from soybeans or extracting soybean protein from defatted soybeans, as a vegetable fiber raw material.

In the course of the research, various enzymatic decomposition methods were attempted to remove the proteins entangled in the fibers, but the proteins could not be removed efficiently.

In addition, cellulase decomposition was attempted, but it was not possible to efficiently decompose fibers intertwined with proteins.

Therefore, by micronizing okara using various methods, followed by proteolytic decomposition and fiber decomposition, we obtained the knowledge that water-soluble polysaccharides can be efficiently obtained depending on the form and degree of micronization of the plant fibers.

Furthermore, the present invention was completed based on the knowledge that this method can be applied to plant fibers other than Okara.

(Means for Solving the Problems) The present invention provides a process for micronizing water-insoluble plant fibers, a process for decomposing proteins contained in the fibers, a process for decomposing the fibers, and a process for refining water-insoluble plant fibers. Water-soluble multi-I! This is a similar manufacturing method.

In the present invention, water-insoluble plant fibers include water-insoluble components of legumes such as soybeans (okara etc.), water-insoluble components of grains such as rice bran and bran, and water-insoluble components derived from plants such as potatoes, vegetables, and fruits. be able to. Among them, okara is preferred because it is stably available.

In addition, when the plant fiber raw material contains skin, navel, etc., such as okara, in order to efficiently obtain the desired water-soluble polysaccharide, the water-insoluble plant fiber of the present invention is preferably a plant cell wall excluding the skin, navel, etc. . This is because if navels and skins are mixed in, the color tone will not be white and the flavor will deteriorate.

In the present invention, water-insoluble plant fibers are first made into fine particles so that the subsequent steps of proteolysis and fiber decomposition can be carried out efficiently.

This micronization is preferably carried out in an aqueous system.The concentration of water-insoluble plant fibers to be dispersed in water will vary slightly depending on the type, micronization method, pH, etc., but any concentration that has fluidity will suffice. For example, when the water-insoluble vegetable fiber is okara and the means for micronization is a homogenizer, the appropriate concentration is 1 to 20%, preferably 3 to 10%, in terms of solid content.

The degree of miniaturization is determined by Coulter Counter (C00LTE
It is appropriate to refine the particles until the average particle size is 35μ or less, preferably 25μ or less.

Any means of refining can be used as long as it can be refined to the above-mentioned particle size, but it is preferable to use shearing force. It is appropriate that the subsequent proteolysis and fiber decomposition are carried out efficiently. Refinement by homogenizing twice or more using a rehomogenizer, which is different from refining by a ball mill, has an excellent effect of tearing bundles of fibers entangled with proteins due to the action of shearing force, and this effect causes later proteolysis and It is presumed that fiber decomposition is facilitated and the target water-soluble polysaccharide can be obtained efficiently. It is difficult to make fibers entangled with proteins, etc., and even if the fibers are made fine in the longitudinal direction, unless the fiber bundles are unraveled, the protein and fibers will protect each other and prevent later protein decomposition. This is because it prevents fiber decomposition.

However, if the fiber bundles are torn in the transverse direction by shearing force, the fiber bundles will be loosened and subsequent proteolysis and fiber decomposition will be easily carried out and the desired water-soluble polysaccharide can be obtained efficiently. be.

When the means of micronization using shear force is homogenizer treatment, the appropriate homogenizer treatment pressure is usually 100 kg/cd or more, preferably 150 kg/cd or more,
Ultra-high pressure of 1000 kg/c1a or higher is also possible. Depending on the homogenizer treatment pressure and the type of water-insoluble vegetable fibers, even one homogenizer treatment can have the effect of loosening the fiber bundles to some extent, but it is preferable to repeat the homogenizer treatment in order to loosen the fiber bundles by tearing them apart. Repeatedly applying shearing force to water-insoluble plant fibers is a new technique, and the fibers that are finely torn through this process can easily undergo the next process of proteolysis and fibrous decomposition. Excellent effect of changing to class II.

Next, the proteins contained in the finely divided fibers are decomposed.

By decomposing the proteins entangled in the fiber bundles, it has the effect of making the fibers more loose and facilitating subsequent fiber decomposition.

Enzymatic decomposition is suitable as a means for decomposing proteins, and any enzymes such as proteases derived from microorganisms such as molds and bacteria, animals, plants, etc. can be used.

These instructors may be either endo-type or exo-type, but preferably endo-type or a combination of endo-type and exo-type.

Further, these instructors may be acidic proteases, neutral proteases, or alkaline proteases, but preferably they are allowed to act in a neutral range. Working in acidic or alkaline regimes often requires subsequent neutralization steps and desalination of increased salinity. However, if the next step to decompose fibers is acid decomposition, it is appropriate to operate in an acidic range to suppress the formation of salts as much as possible. It is appropriate to make it work.

The degree of proteolysis is preferably as high as possible so that the protein removal rate is usually about 60% or more, preferably 70% or more, to facilitate the subsequent fiber decomposition.

Here, the protein removal rate is defined as ((
The value is A-B)÷A)X100 (%).

It is preferable to temporarily remove the decomposed proteins from the proteolyzed water-insoluble plant fibers and the proteins released from the fibers, but if there is a desalting step afterwards, the decomposed proteins can be removed there, so the next fiber can be decomposed as it is. It can also be subjected to a process of

The proteolyzed fibers are then decomposed into fibers, but fiber decomposition can be carried out more efficiently if the proteins are removed prior to this. However, if there is a subsequent desalting step, it is possible to remove the degraded protein at this step.

Decomposition of fibers can be carried out by (1) acid decomposition, (2) alkaline decomposition, (2) decomposition by enzymes such as cellulase, or a combination thereof. Among these, enzymatic decomposition, which can decompose fibers in a neutral range, is the most preferred in that it does not require a subsequent desalting step.

As shown in Example 5 below, the acid decomposition (2) was carried out at pH 1 hour, and the degree of decomposition of the fibers varied depending on the temperature. The lower the pH, the
The longer the time and the higher the temperature, the greater the degree of decomposition of the fibers.The case of okara will be specifically explained.
The longer the time and the higher the temperature, the higher the pH will be.
Fiber decomposition is also possible with H, and the appropriate amount is usually less than 3, preferably 2 or less.

Considering productivity, the lower the pH, the more alkali is required for neutralization afterwards, and more salt is produced, making a desalination step essential.

The lower the pH and the higher the temperature, the shorter the time may be, and usually 30 minutes or more is appropriate.

As for the temperature, if the pH is low and the time is long, a low temperature is sufficient, and if the pH is high and the time is short, a high temperature is required.

Any temperature is possible, and practically room temperature or higher is suitable. However, when the pH is low, care must be taken since monosaccharide production will increase if the treatment is performed at too high a temperature.

In the case of alkaline decomposition (2), the degree of decomposition of the fibers varies depending on the pH for 1 hour, temperature, etc. The higher the pH, the longer the time, and the higher the temperature, the greater the degree of fiber decomposition.The case of okara will be specifically explained.

The longer the pH and the higher the temperature, the more fiber decomposition is possible even at a relatively low pH, usually 11 or higher, preferably 1
2 or more is appropriate. Considering productivity, if the pH is too high, a large amount of acid will be required for neutralization later, and a large amount of salt will be produced, so a desalting step becomes essential.

The higher the pH and the higher the temperature, the shorter the time may be, and usually 30 minutes or more is appropriate.

As for the temperature, if the pH is high and the time is long, a low temperature is sufficient, and if the pH is high and the time is short, a high temperature is required.

Any temperature is possible, and practically room temperature or higher is suitable.

The decomposition of fibers by the enzyme (2) can be carried out in the action pH range and action temperature range of the fiber-degrading enzyme used.

The higher the E/S ratio and the lower the substrate concentration, the more efficiently fibers can be decomposed. It is better to act in the neutral range because there is no need for a subsequent neutralization step, and therefore no salt is produced.
It is preferable that a desalting step is not required afterwards.

One or more types of known fiber-degrading enzymes such as hexicellulase, cellulase, and macerase can be used, and the origin thereof does not matter whether it is derived from microorganisms such as fungi or bacteria, or derived from animals or plants.

The extent to which the fibers are decomposed by the above means is (class II which became water-soluble after decomposition) + (saccharides in the fiber before decomposition) x 100 (%) = solubilization rate, and the solubilization rate is 4.
0% or more, preferably 50% or more, more preferably 60%
% or more is appropriate.

In addition, if the decomposition progresses too much and it is broken down to monosaccharides, it cannot be said to be the desired polysaccharide. Therefore, it is better to suppress the amount of reducing sugars produced during the above fiber decomposition process as much as possible to obtain the desired water-soluble polysaccharide. 0 in a high yield, and does not require the step of removing Group Ii.Normally, the lower the ratio of reducing sugars produced after fiber decomposition to the fibers before fiber decomposition, the lower the reducing sugars after the fiber decomposition. It is preferable because a removing step is not necessary, and it is usually 20% or less, preferably 10% or less, and more preferably 5% or less.

It is possible to separate the water-soluble polysaccharides that have been fiber-decomposed and water-solubilized as described above from the water-insoluble fibers due to insufficient fiber decomposition or other reasons.

As the means for fractionation, any known means such as centrifugation or filtration can be used as long as it is capable of separating water-soluble and insoluble substances.

The water-soluble polysaccharides obtained as described above can be used as they are in beverages and other foods, and can also be concentrated or dried and used in various applications such as beverages and food materials.

In addition, if a large amount of salt is produced in the above process, it is necessary to desalt it.

Desalting means include membrane filtration such as UFSRO, ethyl alcohol,
Known desalting means such as precipitation fractionation using a polar organic solvent such as acetone can be used.

As mentioned above, the desalted water-soluble polysaccharide can be used as is.
It can be used for various purposes after being concentrated and dried.

The water-soluble polysaccharide obtained by the above process ■ does not have the unpleasant flavor of the original water-insoluble fiber, ■ does not have the unpleasant texture such as roughness of the original water-insoluble fiber, and ■ is a functional food. It has a wider range of applications than the original water-insoluble fiber, such as being able to be used in beverages and various food materials.

(Example) Embodiments of the present invention will be described below with reference to Examples.

Example 1 Raw okara obtained in the isolated soybean protein manufacturing process (moisture: approx. 85%)
(wt%, about 20 wt% crude protein in solid content, about 65 wt% total fiber in solid content) to adjust the dry solid content concentration to about 5 wt%, and then
rSub-Micron-disperse made by LIN■
homogenized twice at 200 kg/c-pressure.

Next, an equal weight of water was added and stirred, and Aspergillus 0ryzae-derived protease (titer 240 pu/+mg) was added so that the E/S ratio was 1/100.
Proteolysis was performed at 0°C for 3 hours. However, lpu is Hagiwara-
This is a value measured according to the Anson method.

Then, the solubilized protein was removed by centrifugation (8000 RPM x 30 minutes), and water was added to the precipitated fraction to adjust the solid content concentration to about 4%.

Next, 36% hydrochloric acid was added to adjust the pH to 1, and fiber decomposition was performed at 50° C. for 6 hours.

Next, neutralize with 10% NaOH (pH 7.0), centrifuge (8000 RPM x 30 minutes) to obtain a supernatant (water-soluble polysaccharide fraction), and adjust the final ethanol concentration to 80%. 99% ethanol was added to obtain a precipitate fraction (desalted water-soluble polysaccharide fraction), which was dried with hot air to obtain water-soluble polysaccharide powder.

The yield was 38 parts by weight based on 100 parts by weight of dried Okara.

When I prepared a 5% aqueous solution and drank it, I found that it had no soybean odor or grittiness from the original Okara, and was smooth and smooth in the throat.

Comparative Example 1 A water-soluble Class 11 powder was obtained in the same manner as in Example 1 except for the step of homogenizing using a homogenizer.

The yield was 18 parts by weight based on 100 parts by weight of dried Okara.

Example 2 A water-soluble polysaccharide powder was obtained by performing homogenization only once using a homogenizer and then performing the same process as in Example 1.

The yield was 25 parts by weight based on 100 parts by weight of dried okara.

Example 3 A water-soluble polysaccharide fraction was obtained in the same manner as in Example 1, except that the pH was adjusted to 13 using 30% NaOH instead of hydrochloric acid, and the fibers were decomposed at 80''C.

The yield was 35 parts by weight based on 100 parts by weight of dried Okara.

Example 4 In the same manner as in Example 1, IN hydrochloric acid was added to a solution of okara that had been partially deproteinized by proteolysis to adjust the pH to 4.5.
Cellulase derived from Polypurus tolipifevase (titer 250/MG, manufactured by Kyowa Hakko ■) was added to E/
S was added at a ratio of 1/100, and the fibers were decomposed at 40°C for 10 hours. Neutralize (pH 7) using NaOH IN
After heating at 90°C for 10 minutes to inactivate the enzyme, centrifugation, ethanol fractionation, and drying were performed in the same manner as in Example 1 to obtain water-soluble polyt1! A similar powder was obtained.

The yield was 27 parts by weight based on 100 parts by weight of dried okara.

Comparative Example 2 A water-soluble polysaccharide powder was obtained in the same manner as in Example 1 except for the proteolytic step using protease.

The yield was 14 parts by weight based on 100 parts by weight of dried Okara.

Example 5 In the same manner as in Example 1, raw okara obtained in the isolated soybean protein manufacturing process was homogenized using a homogenizer, and protein-free okara obtained by removing protein using protease (crude protein in dry solid content: Using a suspension with an okara concentration of 1% by weight, the fibers were decomposed by hydrochloric acid decomposition under the conditions shown in Table 1 below, and the decomposition was stopped with a phosphate buffer solution at pH 8. The mixture was centrifuged (12,000 RPM x 10 minutes) to obtain a supernatant (water-soluble polysaccharide fraction), and total sugars and reducing sugars were measured.

Water-soluble factor I for total fiber in deproteinized okara! Table 1 shows the total sugars and the proportion of reducing sugars produced.

Crude protein is Kjeldahl method, total fiber is AOAC-pro.
Sky method, total sugars were determined by the phenol-sulfuric acid method, and reducing sugars were determined by the Somogyi-Nerhun method.

(Margin below) Table 1 Ratio 3 80 3.0 6.0 4.5 1.0 If the temperature is low (below 40''C) and the pH is 2 or less, the formation of water-soluble molecules I! is low and undesirable. In addition, if the pH is low (below 0.5), the temperature is high < (above 80°C), and the time is long (4 hours), the production of reducing sugars increases, which is unsuitable as a water-soluble polysaccharide as it is, and later becomes ethanolic. This is not very preferable because it requires a step to separate reducing sugars and water-soluble polysaccharides by precipitation, etc. Also, if the pH is high (3 or higher), even if the temperature is high (80°C), sufficient fiber decomposition cannot be achieved. I don't like it.

(m* that became water-soluble after decomposition - total I + (class Ii of fibers before decomposition - total fiber in deproteinized okara)
If X100 (%) - solubilization rate, the solubilization rate is 40%
As described above, the target water-soluble polysaccharide could be efficiently obtained by controlling the production of reducing sugars to within 20%.

Experimental Example 1 Okara used in the example (referred to as A), okara that was subjected to homogenizer treatment twice in the same manner as in Example 1 (referred to as B), and okara that was subjected to homogenizer treatment only once as in Example 2 Suspend okara (referred to as C) in 2.5% saline solution and place it in a Coulter counter TA↑■ type (COULT
The average particle size was measured using ERELECTRONIC 5 INC).

The results were as shown in Table-2.

Table-2 Sample particle size (μ) 6 B 19 C31 If not treated with a homogenizer, it would be 60 u or more, but 1
It was found that when treated with a homogenizer twice, the thickness became about 30μ, and when treated twice, the thickness became less than 30μ.

Further, the homogenizer treatment was repeated in the same manner as in Example 1, and the change in particle size was observed. Table 3 shows the number of homogenizer treatments and the particle size.

(Space below) Table 3 Number of times Particle size (μ) 2 9.2 7.0 When observed under a microscope, the more the number of homogenizer treatments increases, the more the Okara fiber bundles become torn and become unraveled. Understood.

Example 7 9 parts of water was added to 1 part of defatted wheat bran passed through a 60-mesh sieve (6.7% moisture, 17.6% crude protein, about 52% total fiber), mixed and stirred, and homogenized. Process 2
Apply twice, add equal weight of water, adjust pH to 6.5,
/S ratio is 1/100.
protease derived from S. soryzae (titer 160 pu
/mg) was added and the protein was decomposed at 50°C for 2 hours.

Next, Pen1cilliu＋＊ funiculo
Sum-derived cellulase (titer 8u/manufactured by Peng GS Sigma) was added at an E/S ratio of 2/100, and incubated at 40°C for 4 hours.
Time fibers decomposed. The enzyme was inactivated by heating at 90° C. for 10 minutes, followed by centrifugation, ethanol fractionation, and drying in the same manner as in Example 1 to obtain water-soluble polysaccharide N at a yield of 16% based on the raw material.

Comparative Example 3 A water-soluble polysaccharide was obtained in the same manner as in Example 7 except that the homogenizer treatment was not performed. The yield based on the starting material was 7%.

(Effects) As described above, the present invention makes it possible to efficiently produce water-soluble polysaccharides with excellent flavor and texture (such as smoothness in the throat) from water-insoluble plant fibers.

Claims (2)

[Claims] (1) A method for producing a water-soluble polysaccharide, which includes the steps of micronizing water-insoluble plant fibers, decomposing proteins contained in the fibers, decomposing the fibers, and fractionating water-soluble polysaccharides. (2) The manufacturing method according to claim 1, wherein the micronization is carried out by applying shearing force in an aqueous system.