JP3354592B2 - Method for producing oligosaccharide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an oligosaccharide. Specifically, the present invention provides a method capable of efficiently producing an oligosaccharide which is extremely effective for promoting the growth of Bifidobacterium by a simple operation.

[0002]

2. Description of the Related Art In recent years, flora (bacteria) in the intestine has been developed.
Has become known to be closely related to human health, and interest in intestinal bacteria has increased. Among the intestinal bacteria, bifidobacteria in particular are known to exhibit beneficial physiological effects such as inhibiting the growth of putrefactive bacteria and pathogenic bacteria in the intestine, and various attempts have been made to increase bifidobacteria. . As one of them, a method of growing bifidobacteria using fructooligosaccharides or soybean oligosaccharides having hexoses such as fructose as constituent sugars has been proposed, and these saccharides are bifidobacteria and Although it is decomposed and digested by useful bacteria such as lactic acid bacteria and proliferates, it is also decomposed and digested by harmful bacteria such as Bacteroides fragilis, Bacteroides vulgatus and Escherichia coli, and such harmful bacteria It also has the disadvantage of having a growth promoting effect.

[0003] The present inventors have studied on oligosaccharides capable of selectively growing bifidobacteria without growing harmful bacteria. Among the oligosaccharides, the oligosaccharides mainly consist of pentose components such as xylose and arabinose. Oligosaccharides have been found to be capable of growing useful bifidobacteria while suppressing the growth of harmful bacteria, and have previously filed an application for an invention relating to a bifidobacterium growth promoter containing arabinoxylo-oligosaccharide as an active ingredient (Japanese Patent Application Hei 3-208770).

The above-mentioned Japanese Patent Application No. Hei 3-2087, filed by the present inventors.
The arabinoxylo-oligosaccharides used in the No. 70 bifidobacteria promoter are disclosed in Japanese Patent Application No. Hei.
162788 (JP-A-4-53496) and Japanese Patent Application No. 3-282400. The former method (JP-A-4-53496) hydrolyzes water-insoluble hemicellulose obtained from wheat bran, water-soluble 60% ethanol-insoluble hemicellulose, or water-soluble anion exchanger non-adsorbable hemicellulose with endoxylanase. In the latter method (Japanese Patent Application No. 3-282400), an arabinoxylan-containing site such as a bark of a grass plant is heated at a temperature in the presence of moisture. 1
This is a method for producing an arabinoxylo-oligosaccharide by subjecting a plant cell wall-disintegrating enzyme to an action after pressurizing and heating at 00 to 145 ° C and a pressure of 1 to 4 atm.

[0005] Any of the above-mentioned methods makes it possible to smoothly produce useful oligosaccharides consisting mainly of arabinose and xylose from wheat bran which has been conventionally used mainly for livestock feed. It has great technical significance. However, the former method extracts hemicellulose from wheat bran by alkali extraction or the like, and hydrolyzes the resulting hemicellulose using an enzyme, so that the hemicellulose is used in the extraction step and extraction of hemicellulose from wheat bran. It is necessary to neutralize the alkali, remove the salt generated by the neutralization, and the like, and the process is complicated, and the cost cannot be denied. The latter method has the advantage that arabinoxylo-oligosaccharides can be obtained directly from the skin of grasses such as wheat bran without performing hemicellulose extraction treatment. Need.

On the other hand, in the production of wheat starch, dough is manufactured by adding water to the flour and kneading, and the dough is washed with water, and the washed product is divided into water-insoluble gluten and a starch-containing emulsion, and the starch is mixed with starch. A method of separating and recovering starch from a contained emulsion is generally employed. In that case, the emulsion after separating and recovering the starch has conventionally been mostly discarded as wheat starch waste liquid, and only part of the emulsion has been used as livestock feed in a liquid state or in a solid state. However, it has been difficult to handle wastewater from the viewpoint of wastewater treatment.

[0007] In particular, from a wheat starch waste liquid generated in the process of producing wheat starch from wheat flour, a colored water-insoluble fiber called red cake mainly composed of fine pieces of wheat bran and a fiber contained in endosperm A white water-insoluble fibrous material called white lees, which is mainly composed of the white lees, is obtained, and the portion corresponding to the white lees is obtained by applying the present application (Japanese Patent Application No. 2-418026) by the present inventors. An effective use as a fiber and a smooth recovery method have been found, but there has been no effective use of red cake so far, and its treatment has been a problem.

[0008]

Under the circumstances described above, the present inventors:
The oligosaccharides containing arabinose and xylose, especially the arabinoxylo-oligosaccharides, which do not show the growth promoting action of harmful bacteria and have the growth promoting action of the useful bacterium Bifidobacterium, go through complicated processes such as alkali extraction and heat treatment under pressure. Further research has been conducted in order to develop a method that can be manufactured efficiently with a simple operation without any problems. In addition, the present inventors have continued research on the effective use of water-insoluble fibers contained in wheat starch waste liquid, particularly fibers recovered as red cake.

As a result, when a water-insoluble fiber contained in a wheat starch waste liquid discharged at the time of producing starch and gluten from wheat flour is used, and a cell wall degrading enzyme is directly acted on the fiber, alkali extraction is required. The present inventors have found that the intended useful oligosaccharides rich in arabinose and xylose can be produced very easily and efficiently without performing any recovery of hemicellulose or any heat treatment under pressure, and completed the present invention.

Accordingly, the present invention is a method for producing an oligosaccharide, comprising hydrolyzing a water-insoluble fiber derived from wheat flour with a cell wall degrading enzyme.

In the present invention, any water-insoluble fiber derived from wheat flour can be used as the water-insoluble fiber derived from wheat flour, and the method of collecting and obtaining the water-insoluble fiber is not particularly limited. However, as a water-insoluble fiber,
It is desirable to use the water-insoluble fiber contained in the wheat starch waste liquid discharged when producing starch from wheat flour. Among them, the use of fiber called so-called red cake is particularly effective in the use of red cake, which has not been known for any useful use, and the use of bifidobacteria in oligosaccharides obtained therefrom. It is preferable because it contains a lot of arabinose and xylose useful for growth.

In producing oligosaccharides by allowing a cell wall-degrading enzyme to act on water-insoluble fiber in a wheat starch waste liquid, a cell wall-degrading enzyme is directly allowed to act in a liquid state on a wheat starch waste liquid containing water-insoluble fiber. Is also good. However, it is more preferable to recover the water-insoluble fiber composed of red lees, white lees, or a mixture thereof from the wheat starch waste liquid in a solid state, and to cause the cell wall degrading enzyme to act on the recovered solid fiber. However, salts, water-soluble proteins and the like are removed, and as a result, oligosaccharides with high purity can be obtained.

There is no particular limitation on the method for recovering the water-insoluble fiber from the wheat starch waste liquid as a solid such as red cake, white cake, or a mixture thereof. For example, wheat starch may be produced from wheat flour by a conventionally known method, and a solid water-insoluble fibrous material consisting of red cake, white cake or a mixture thereof by-produced at that time may be used as it is. Or,
The water-insoluble fiber may be recovered in the following manner according to the method of Japanese Patent Application No. 2-418026 described above by the present inventors. In particular, in the case of the following method, it is a raw material of the present invention. Water-insoluble fibers can be obtained easily and efficiently.

[0014] According to the method of Japanese Patent Application No. 2-418026.
Water-insoluble fiber recovery methodWater is added to wheat flour and kneaded to produce a dough or an emulsion, and the dough or the emulsion is washed with water, and the washed product is separated into gluten and a starch-containing emulsion to obtain a starch-containing milk. The starch is separated and recovered from the suspension. Water is added to the residue (liquid) after separating the starch to form a water-diluted emulsion, which is then centrifuged to contain a colored solid equivalent to red cake and a solid equivalent to white cake. The white solid, or the colored solid, the white emulsion, and the water, and then drying the colored solid and the white emulsion to obtain red cake and white cake. Are collected and used as the water-insoluble fiber in the present invention.

[0015] In the present invention, the water-insoluble fiber derived from wheat flour is hydrolyzed with a cell wall degrading enzyme to produce an oligosaccharide. The cell wall degrading enzyme used in the present invention may be any one having xylanase activity,
For example, "Cellulase Onozuka" manufactured by Yakult, "Pectoliase Y-23" manufactured by Seishin Pharmaceutical Co., Ltd., "Meizerase" manufactured by Sanko Junyaku Co., Ltd. can be mentioned.

The cell wall degrading enzyme may be used in a free state or immobilized on a carrier, and the hydrolysis treatment with the cell wall degrading enzyme may be performed by a continuous method or a batch method. The treatment is carried out by appropriately selecting various conditions such as the origin of the cell wall degrading enzyme, the amount used, temperature, pressure, pH, time and the like during the treatment. When the water-insoluble fiber is collected from the wheat starch waste liquid as a solid such as white cake and red cake, and the solid material is subjected to a hydrolysis treatment using a cell wall degrading enzyme, the solid consisting of the water-insoluble fiber is used. The substance is preferably dispersed or suspended in water to perform the enzyme treatment.

In general, but not limited to, 1 to 100 units, preferably 5 to 50 units, of cell wall degrading enzyme is used as a xylanase per 1 g of water-insoluble fiber at 30 to 70 ° C. Is 50-60
At a temperature of 4 ° C., pH 4-7, preferably pH 5-6,
If the hydrolysis reaction is carried out in less than an hour, preferably in less than 1 hour, the target oligosaccharide can be obtained in good yield and at low cost.

One indication of the end of the hydrolysis reaction is when the viscosity of the suspension containing the water-insoluble fiber is no longer reduced. At that point, the enzyme is inactivated by heating or the like. Good. When it is desired to control the reaction conditions more precisely, the reaction may be performed while analyzing the composition of the enzyme reaction product by high performance liquid chromatography (HPLC) or the like.

The oligosaccharide-containing hydrolyzate obtained as described above is treated with one or more of separation means such as an ultrafiltration membrane, activated carbon, gel filtration chromatography, and ion exchange resin. A target oligosaccharide mainly containing arabinoxylo-oligosaccharide can be separated and recovered.

Specific examples of the method for separating and recovering an oligosaccharide from a hydrolyzed solution are as follows, but are not limited thereto. After the oligosaccharide-containing hydrolyzate is centrifuged, the supernatant is applied to a microfilter (for example, 0.45 μm in pore size), and the filtrate is dried to recover an oligosaccharide mainly composed of arabinoxylo-oligosaccharide. After the oligosaccharide-containing hydrolyzate is centrifuged, the supernatant obtained by treating the supernatant with an ultrafiltration membrane is dried, and the oligosaccharide mainly consisting of arabinoxylo-oligosaccharide is recovered.

After the oligosaccharide-containing hydrolyzate is centrifuged to remove solids, it is desalted through an ion exchange resin, and the supernatant is subjected to a microfilter (pore size: 0.45 μm).
m) and then pass through an activated carbon column to separate it into an activated carbon adsorption section and a non-adsorption section.
Then, the eluate is dried to recover an oligosaccharide mainly composed of arabinoxylo-oligosaccharide. After the oligosaccharide-containing hydrolyzate is centrifuged, the supernatant is passed through a microfilter (for example, 0.45 μm in pore size), and the filtrate is concentrated to perform gel filtration chromatography (for example, Toyopearl HW-40s manufactured by Tosoh Corporation). , The eluate is fractionated, and dried to recover a single oligosaccharide.

An oligosaccharide produced by the method of the present invention,
In particular, the oligosaccharides obtained by the above-mentioned recovery methods are arabinoxylo-oligosaccharides in which xylose and arabinose are bonded and / or xylo-oligosaccharides in which only xylose is bonded, and further monosaccharides such as xylose, arabinose, and glucose. Is contained in a small amount. The mixed oligosaccharide contains particularly a large amount of arabinoxylo-oligosaccharide (usually about 70-80%), and the arabinoxylo-oligosaccharide has a composition formula (Xyl) n (Ara) m (where Xyl: xylose , Ara: arabinose, n: number of xylose bonds,
m: the number of arabinose bonds), usually n
= 2-10, m = 1-10.
The mixed oligosaccharides may be used in the form of a mixture, or may be separated and recovered and used as single oligosaccharides by the above-described recovery method or the like.

In the case of using wheat bran or the like, an oligosaccharide cannot be obtained even when a cell wall-degrading enzyme is directly acted on the other hand. The rationale for obtaining sugars directly and easily is not clear, but is presumed to be due to the following reasons.

That is, the water-insoluble fiber derived from wheat flour such as red cake and white cake recovered from the wheat starch waste liquid used in the present invention is mainly contained in fine fragments of wheat bran and wheat endosperm generated during milling. Made of water-insoluble fiber. Since these water-insoluble fibers are contained in flour, which is the final product after sieving in the milling process, ordinary wheat bran having a large particle size to be sieved in the first stage of the milling process is used. 200μm
It is composed of fine particles having a finer particle size. Therefore, its surface area is large and it is in a state where it easily comes into contact with the enzyme, and furthermore, the bond between cellulose and hemicellulose in the water-insoluble fiber is partially broken, and is not as strong as wheat bran. In addition, when collecting wheat starch and gluten from wheat flour, they are fully hydrated because they undergo steps such as kneading and washing, so that cell-wall degrading enzymes can easily penetrate into the water-insoluble fiber cell walls. Has become. As a result, without pretreatment such as extraction or heating and pressure treatment of hemicellulose with alkali, hydrolysis is smoothly performed only by directly acting on cell wall degrading enzyme on water-insoluble fiber derived from flour. It is considered that the desired oligosaccharide is obtained.

Since the oligosaccharides produced in the present invention are mainly composed of arabinoxylo-oligosaccharides, they do not have the effect of promoting the growth of harmful bacteria such as Bacteroides fragilis, Bacteroides burgatas, and Escherichia coli. Bifidobacterium, a useful bacterium, can be selectively grown, and can be usefully used for functional foods and other uses.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples and the like, but the present invention is not limited thereto. All percentages in the following examples are by weight. In the following examples, the total sugar content was determined by the phenol-sulfuric acid method. Furthermore, the oligosaccharide content and the sugar composition in the obtained product were measured by the following methods.

[Measurement of Oligosaccharide Content] After dissolving 50 mg of the product obtained in the following example in 1 ml of pure water, HPLC analysis was carried out under the following conditions to obtain a chromatogram, and each chromatogram was obtained. The oligosaccharide content was determined from the peak area ratio. HPLC analysis conditions : Injection volume: 20 μl Column: Ultrahydrogel 250 × 2 (manufactured by Waters) Flow rate: 0.8 ml / min Temperature: 70 ° C. Detector: differential refractometer

[Measurement of Sugar Composition] To 20 mg of the product obtained in each of the following examples was added 2 ml of 2N trifluoroacetic acid, and the mixture was hydrolyzed at 100 ° C. for 2 hours. Was subjected to HPLC analysis to determine the sugar composition.

Reference Example 1 [Recovery of Water-Insoluble Fiber Derived from Flour] A water-insoluble fiber was recovered from wheat flour by the following method according to Japanese Patent Application No. 2-418026. That is, 6 parts of water was added to 10 parts of flour (protein content: 16.0%) and kneaded at a temperature of about 20 ° C. for 20 minutes using a kneader kneader to produce a dough. Next, 60 parts of water was added to 16 parts of the dough, and the cloth was washed with water at a water temperature of about 20 ° C. for 60 minutes using a washing apparatus (single-screw screw conveyor). As a result of this washing step, wheat gluten in the dough is separated as a water-insoluble solid, so the gluten solid was removed and the aqueous phase consisting of a starch-containing emulsion was recovered. Next, the starch-containing emulsion recovered above is treated using a 300-mesh vibrating sieve to separate the starch and to remain on the sieve.
A strike-like residue (water content about 95%) was recovered.

Next, twice the amount of water was added to the paste-like residue recovered in the above step to prepare a water-diluted emulsion having a solid concentration of about 2%. Furthermore, a continuous centrifugal separator [Sharpless Super Decanter P-660]
Type: Tomoe Kogyo Co., Ltd.], the supply amount of the water-diluted emulsion is 2000 kg / h, and the rotation speed of the rotary cylinder is 5000 rpm.
m (2130G), conveyor rotation speed 3000 rpm
When centrifugation is performed, colored water-insoluble fiber corresponding to red cake is discharged from the upstream outlet, while white emulsion containing water-insoluble fiber corresponding to white cake is discharged from the downstream outlet. It was recovered at a rate of 1900 kg / h. Each of the colored water-insoluble fiber and the white emulsion collected above was dried to obtain so-called red cake and white cake. The general analysis values and the neutral sugar composition of the red cake and white cake obtained above were as shown in Table 1 below.

Reference Example 2 A red cake and a white cake were prepared in the same manner as in the above-mentioned Reference Example 1 by changing the type of flour, and their general analysis values and sugar composition were examined. As shown in FIG. For reference, Table 1 also shows general analysis values and neutral sugar composition of wheat bran.

[0032]

[Table 1]  General analysis value Sugar composition  Moisture Ash Protein Glc¹⁾ Xyl²⁾ Ara³⁾ (%) (%) (%) (%) (%) (%) Reference Example 1  Red cake 10.0 1.5 7.2 20.2 48.3 31.5 White cake 10.0 0.6 6.0 65.2 20.2 14.6Reference Example 2  Red cake 4.1 1.2 6.9 51.0 30.9 18.1 White cake 4.5 0.7 4.3 63.4 23.1 13.5Wheat bran 12.6 5.1 16.4 32.1 42.9 25.0  1) glucose, 2) xylose, 3) arabinose

From the above Table 1, it can be seen from the above table that the red insoluble and white lees, which are water-insoluble fibers derived from wheat flour, have a lower content of substances such as ash and protein that become impurities in the preparation of oligosaccharides than wheat bran. However, it is preferable that it is preferable as a raw material for producing an oligosaccharide. Glucose is considered to be mainly derived from wheat starch. Furthermore, the ratios of glucose, xylose, and arabinose in the red cake between Reference Examples 1 and 2 are considerably different, but this is due to the degree of separation from starch during the preparation of red cake. Seem. Glucose becomes an impurity during the production of oligosaccharides containing arabinoxylo-oligosaccharide as a main component. Therefore, it is preferable to separate glucose as much as possible during the production of water-insoluble fibers such as red cake. When red cake is prepared by the method of Japanese Patent Application No. 2-418026 described above by the present inventors, the ratio of glucose contained in the red cake is small, and the red cake is a water-insoluble fiber according to the present invention. Suitable for quality.

<< Example 1 >> Red cake 5 prepared in Reference Example 1
g in 50 mM acetate buffer at pH 5.5,
100 ml of a 5% (w / v) suspension of red cake was prepared. After heating this to 50 ° C., 5 mg of cellulase Onozuka RS (manufactured by Yakult Honsha) (42 units as xylanase)
s) was added and a hydrolysis reaction was performed for 30 minutes. Then
The enzyme was inactivated by boiling at 100 ° C. for 10 minutes. After allowing to cool, the mixture was centrifuged at 9000 G for 30 minutes, and the obtained supernatant was filtered through a microfilter having a pore size of 0.45 μm, and the filtrate was lyophilized to obtain a solid. The yield (%), total sugar content, oligosaccharide content and sugar composition of the solid obtained here were measured by the methods described above. The results are shown in Table 2 below.
Shown in

Example 2 An oligosaccharide was produced in the same manner as in Example 1 except that the white cake prepared in Reference Example 1 was used. Table 2 shows the results.

<< Example 3 >> Red cake 5 prepared in Reference Example 1
g in 50 mM acetate buffer at pH 5.5,
100 ml of a 5% (w / v) suspension of red cake was prepared. The mixture was heated to 60 ° C., and 70 μl (10 KNU as amylase) of Tamamill 120 L (manufactured by NOVO) was added thereto. The mixture was allowed to react for 1 hour. After adding a 50 mM acetate buffer at pH 5.5 to a new volume of 100 ml, the mixture was heated to 50 ° C., 5 mg of cellulase Onozuka RS (42 units as xylanase) was added, and a hydrolysis reaction was carried out for 30 minutes. Was. Next, the enzyme was inactivated by boiling at 100 ° C. for 10 minutes. After allowing to cool, the mixture was centrifuged at 9000 G for 30 minutes, and the obtained supernatant was filtered through a microfilter having a pore size of 0.45 μm, and the filtrate was lyophilized to obtain a solid. The yield (%), total sugar content, oligosaccharide content and sugar composition of the solid obtained here were measured by the methods described above. The results are shown in Table 2 below.

Example 4 1.5 kg of the red cake prepared in Reference Example 1 was suspended at pH 5.5 in a 50 mM acetate buffer, and 15 L of a 10% (w / v) suspension of red cake was prepared. Was prepared. This was put into a fermenter MBU-50 (manufactured by Tokyo Rikakiki Co., Ltd.) and heated to 60 ° C. To this, 21 ml of Termamil (3000 KN as amylase) was added.
U) and reacted for 1 hour, and then centrifuged filter cloth [Co., Ltd.]
The reaction solution was removed using Tanabe Iron Works. The residue is again put into the fermentor MBU-50, and the pH is newly adjusted to 50 at pH 5.5.
The volume was adjusted to 15 liters with the addition of mM acetate buffer. Thereafter, the mixture was heated to 50 ° C., 1.5 g of cellulase Onozuka RS (12,450 units as xylanase) was added, and a hydrolysis reaction was performed for 30 minutes. Then, at 100 ° C
For 10 minutes to inactivate the enzyme. After allowing to cool, a filtrate was prepared using a centrifugal filter cloth, and a filter aid (manufactured by Showa Chemical Industry Co., Ltd .; Radiolight 2000) was added to the filtrate at 1% (w / v).
In addition, suction filtration was performed with a filter having a pore size of 5 μm. The obtained filtrate was spray-dried with a spray drier to obtain a dried product. The yield (%), total sugar content, oligosaccharide content and sugar composition of the obtained dried product were measured by the above-mentioned methods. The results are shown in Table 2 below.

By the way, the chromatogram obtained when the dried product obtained in Example 4 was subjected to the above-mentioned HPLC analysis was as shown in FIG. On the other hand, when HPLC analysis was carried out in the same manner using a substance having a known molecular weight, in the case of pullulan having a molecular weight of 5800, it was located at 19.20 minutes.
For glucose having a molecular weight of 180, a peak appeared at a position of 27.69 minutes, and for xylose and arabinose having a molecular weight of 150, a peak appeared at a position of 28.55 minutes. From this, in the chromatogram of FIG. 1, peaks 1 to 3 having higher molecular weights on the left side than peak 4 (molecular weight 180) almost corresponding to glucose corresponded to oligosaccharides, and generation of oligosaccharides was confirmed. .

Comparative Example 1 One liter of a 5% (w / v) suspension of wheat bran was prepared by suspending 50 g of a freeze-dried wheat bran washed with water in a 50 mM acetate buffer at pH 5.5. . After heating this to 50 ° C., 50 mg of cellulase Onozuka RS (420 units as xylanase)
s) was added and a hydrolysis reaction was performed for 30 minutes. Then
The enzyme was inactivated by boiling at 100 ° C. for 10 minutes. After standing to cool, the mixture was centrifuged at 9000 G for 30 minutes. Radiolite 2000 was added to the obtained supernatant at a ratio of 1% (w / v), and the mixture was filtered through a filter having a pore size of 5 μm, and the filtrate was freeze-dried. A solid was obtained. The yield (%), total sugar content, oligosaccharide content and sugar composition of the solid obtained here were measured by the methods described above. The results are shown in Table 2 below.

Comparative Example 2 One liter of a 5% (w / v) suspension of wheat bran was prepared by suspending 50 g of a freeze-dried wheat bran washed with water in a 50 mM acetate buffer at pH 5.5. . This was put in an autoclave at 120 ° C., 2.
Pressure and heat treatment was performed at 1 atm for 10 minutes. After cooling, the mixture was heated to 50 ° C., and 50 mg of cellulase Onozuka RS (420 units as xylanase) was added thereto, and a hydrolysis reaction was performed for 30 minutes. Subsequently, the enzyme was inactivated by boiling at 100 ° C. for 10 minutes. After cooling, the mixture was centrifuged at 9000 G for 30 minutes, and Radiolite 2000 was added to the obtained supernatant at 1%.
(W / v) and filtered through a filter having a pore size of 5 μm, and the filtrate was freeze-dried to obtain a solid. The yield (%), total sugar content, oligosaccharide content and sugar composition of the solid obtained here were measured by the methods described above. The results are shown in Table 2 below.

[0041]

[Table 2] Example Comparative Example 1 2 3 4 1 2 Solid yield (%) 40.1 32.5 30.4 28.8 3.6 23.7 Total sugar (%) 88.7 86.3 88.1 90.0-85.8 Oligosaccharide content 16.4 11.8 16.3 15.1-12.1 Sugar composition Glc ¹⁾ (%) 43.1 47.8 25.0 28.2-25.7 Xyl ²⁾ (%) 38.7 33.3 51.9 48.7 − 57.2 Ara ³⁾ (%) 18.2 18.9 23.1 23.1 − 17.1 Total (%) 100.0 100.0 100.0 100.0 − 100.0 1) glucose, 2) xylose, 3) arabinose

From the results in Table 2 above, it can be seen from Examples 1 to 5 of the present invention.
In Comparative Example 4, although the water-insoluble fiber derived from the flour was simply hydrolyzed directly with the cell wall degrading enzyme without performing the pretreatment, the pretreatment such as pressurization and heating of the fiber was performed. It is understood that an oligosaccharide containing a large amount of arabinose and xylose can be obtained in a higher yield than in Examples 1 and 2. Moreover, when red cake is used as the water-insoluble fiber derived from flour, an effective oligosaccharide having a low glucose content and a high arabinose and xylose content, which promotes the growth of bifidobacteria, is obtained.

[0043]

Industrial Applicability According to the method of the present invention, oligosaccharides containing a large amount of arabinose and xylose, which do not exhibit the growth promoting effect of harmful bacteria and have the growth promoting effect of the useful bacterium Bifidobacterium, particularly arabinoxylo-oligosaccharides, It can be manufactured with a simple operation and high yield without going through complicated pretreatment steps such as extraction and heat treatment under pressure. Furthermore,
According to the present invention, the water-insoluble fiber in the wheat starch waste liquor that has been difficult to handle so far can be effectively used, especially the fiber recovered as red cake, and there is almost no effective use in the past. Flour-derived water-insoluble fibers can be converted into useful oligosaccharides.

[Brief description of the drawings]

FIG. 1 is a view showing a chromatogram of each fraction by HPLC analysis of a product obtained in Example 4.

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Claims (1)

(57) [Claims] 1. A method for producing an oligosaccharide, comprising hydrolyzing a water-insoluble fiber derived from flour with a cell wall degrading enzyme.