JP3243559B2 - Process for producing water-soluble dietary fiber mainly composed of barley bran-derived β-glucan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing water-soluble dietary fiber containing β-glucan as a main component from barley bran, a by-product of barley barley.

[0002]

2. Description of the Related Art Dietary fiber has recently attracted attention as a health food material. Dietary fiber is roughly classified into two types.
One of them is insoluble dietary fiber, whose primary effects are increased stool volume, reduced transit time of intestinal contents, intestinal pressure,
There is a decrease in abdominal pressure, and as a result, it is said to be effective in preventing and treating various colorectal diseases such as constipation and colorectal cancer. The other is
It is a water-soluble dietary fiber, and its primary effects are activation of gastrointestinal tract activity, decreased digestion and absorption of dietary components, reduced bile acids circulating in the enteroliver, and changes in the type and metabolism of intestinal bacteria. It is said to be effective in preventing and treating constipation, colorectal disease, obesity, diabetes, hyperlipidemia and the like.

[0003] The insoluble dietary fiber has drawbacks due to its physicochemical properties, such as insolubility in water, no matter how fine it is made, and greatly impairing the texture in the mouth. Therefore, attempts have been made to extract water-soluble dietary fiber having no such defects from many vegetable fiber raw materials.

[0004] Specific examples of these attempts include a method in which corn hulls are treated with hot water at 130 to 160 ° C to extract hemicellulose (JP-A-64-62303) or a method in which wheat bran is treated with an alkaline aqueous solution. Method for extracting hemicellulose (Japanese Patent Laid-Open No. 2-1701)
A method in which oat flour is gelatinized with starch and treated with α-amylase to obtain a water-soluble component (Japanese Unexamined Patent Publication No. 5-504068).

By the way, barley contains β- (1,3) (1,4) -D as water-soluble dietary fiber, in addition to arabinoxylan, which is a hemicellulose component contained in the hull of wheat or the like.
-A great feature is that it contains a large amount of glucan. It is considered that the physiological action of β-glucan has a particularly strong effect of suppressing serum cholesterol and blood sugar level elevation by decreasing serum insulin concentration. However, in recent years, our dietary habits have been more similar to those of Western countries than before,
It is said that the intake of plant fiber is greatly reduced.
The National Nutrition Survey also reveals a decrease in dietary fiber intake from cereals, arguing that a decrease in barley intake is attributable to a lack of dietary fiber intake. Some are experts. Therefore, it is necessary to separate and purify a water-soluble dietary fiber having a specific physiological action, that is, β-glucan derived from barley bran, from the bran, which is a by-product of barley barley, both industrially and in terms of effective use of the by-product. ing.

[0006] However, when the β-glucan is extracted from barley bran, when the above-mentioned pressurized hot water treatment is carried out, the starch is remarkably gelatinized and has a high viscosity, which greatly hinders the extraction operation. In addition, in the case of alkali extraction, problems such as operations such as neutralization of the extract and treatment of the extraction residue occur. Also, α-
Although the viscosity decreases when treated with amylase, the production and contamination of dextrin without human digestive enzyme resistance is remarkable, and the resulting extract has a reduced content of the target β-glucan. Furthermore, if the starch is removed from barley bran in advance by physical treatment such as sieving, water washing, or chemical treatment such as enzyme treatment, the extract obtained therefrom is:
β-glucan content is low. The reason is that β
-It was thought that the reason was that glucan was present more in the starch fraction and the aleurone layer.

[0007]

Under such technical and industrial conditions, a water-soluble food containing β-glucan as a main component, which is expected to be more useful than barley bran, a by-product of low value-added cereal barley. It has been demanded that barley bran be effectively used by extracting and purifying fibers easily and with a high content.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses barley bran containing a large amount of desired β-glucan and having a milling yield of 82% or less, which is generated from sticky barley, and is heat-resistant. A method for producing a water-soluble dietary fiber, comprising adding a soluble α-amylase, extracting with hot water, and further adding a glucoamylase to digest a digestible dextrin solubilized.

The details of the present invention will be further described below with reference to preferred embodiments.

In the present invention, barley bran is used as an extraction raw material. As shown in Table 1, the barley raw materials are roughly classified into two types: bark and bark, each of which has stickiness and stickiness. Skinning is further classified into small grains and large grains. Therefore, although sticky barley is preferably used as a raw material for extracting β-glucan, bare wheat is more preferably used in view of the supply of raw materials.

[0011]

[Table 1] Barley bran is generated by grinding barley for staple food. Raw materials having a milling yield of 55% or less are no longer referred to as bran when milled to less than 55%. However, in the present invention, crushed granules having a milling yield of 55% or less are collectively referred to as barley brans, including barley bran.

The details of this polishing step will be described with reference to the flowchart of FIG.

Table 2 shows the milling yield of the generated bran in each step.

[0014]

[Table 2] The selected barley is rough-milled with a grinding mill to remove the outer skin (husk, pericarp, seed coat) and some aleurone layers. This step is usually performed to a milling yield of 82%. The bran generated at this time is referred to as rough milling bran. This bran is not suitable as an extraction raw material because of its coarse particle size and low β-glucan content.

After that, the raw materials after the rough milling process are subjected to different manufacturing processes depending on the final product form.

First, in the barley processing of rice, the barley is cut along a center line of barley, that is, a so-called black line in order to form rice grains. Then, long-step milling is performed by a grinding mill to remove the aleurone layer. This process usually has a milling yield of 74%
Do until. The bran generated at this time is called a long-process bran. This bran contains a relatively large amount of β-glucan, which is preferable as an extraction raw material.

Next, steaming is performed, and finish grinding is performed with a grinding mill in order to remove black lines. This step is usually performed up to a milling yield of 53%. The bran generated at this time is called a finishing bran. This bran contains a large amount of β-glucan and is preferable as an extraction raw material.

The raw material after the above steps is finally polished to produce a product (rice grain barley).

On the other hand, in the pressing process, after the rough milling step, long-step milling is performed by a grinding mill to remove the aleurone layer and a part of the starch layer. This step is usually performed up to a milling yield of 65%. The bran generated at this time is called a long-process bran. This bran contains a relatively large amount of β-glucan, which is preferable as an extraction raw material.

Next, horizontal polishing is performed by a grain friction type polishing machine in order to perform water adjustment and refine. This step is usually carried out to a milling yield of 55%. The bran generated at this time is called a horizontal bran. This bran contains a large amount of β-glucan and is preferable as an extraction raw material.

The raw material having been subjected to the above steps is finally pressed to a barley pressure of about 1 mm by a pressing machine to obtain a product (pressed wheat).

As described above, rice bran is generated in a wide variety of processes in the barley-milling process. Raw materials for extracting β-glucan are bran having a high β-glucan content, that is, a milling yield of 82 to 53%.
Bran other than so-called rough milling bran is preferred. More preferably, milling yield in rice grain barley processing 74 ~
Either bran generated at 53%, so-called finished bran, or bran generated at a milling yield of 65 to 55% in the pressing and barley processing, so-called horizontal bran, or a mixture of both.

The method for extracting β-glucan from barley bran in the present invention is as follows: 100 parts by weight of barley bran, 500 to 1500 parts by weight of hot water at 80 to 95 ° C., and heat-resistant α-amylase per 1 kg of raw material , 3,000-30,000
It is desirable to add a unit and extract while stirring at 80 ° C to 90 ° C for 1 to 12 hours. Thereafter, 400 to 4,000 units of glucoamylase are added to 1 kg of the raw material to digest the solubilized digestible dextrin, and
It is preferable to digest while stirring at 0 ° C to 60 ° C for 3 to 24 hours. As described above, digestive dextrin contained in components solubilized from starchy barley bran is decomposed into monosaccharides only by simple operations of extraction and reaction with addition of enzymes, and as a result, the solubilized fraction The polysaccharide contained therein has a high content of indigestible β-glucan. At the same time, since the viscosity is extremely reduced, there is an advantage that the operation of solid-liquid separation becomes easy.

The term "thermostable α-amylase" as used herein refers to a product which hydrolyzes an α-1,4 glycosidic bond such as gelatinized starch or glycogen at an arbitrary position and, as a decomposition product, soluble dextrin or oligo and a small amount of glucose. Is caused. Glucoamylase degrades the α-1,4 glycosidic bond of soluble starch in glucose units sequentially from the non-reducing end.

The titer of the thermostable α-amylase was measured using a potato starch as a substrate and blue by iodine coloration.
The size refining power is determined from the% reduction in Value. That is, the Blue Value of a 1% starch solution was heated at 40 ° C.,
The amount of enzyme to be reduced by 1% per minute is defined as one unit. The glucoamylase titer was measured using soluble starch as a substrate at pH 4.5 and 40 ° C. under reaction conditions.
The amount of the enzyme that produces 10 mg of glucose per minute is defined as one unit.

Examples of the heat-resistant α-amylase include commercially available products such as “Amylase AH Amano” manufactured by Amano Pharmaceutical Co., Ltd., “Termamyl” manufactured by Mitsui & Co., Ltd., and “Spytase HS” manufactured by Nagase & Co., Ltd. Can be used. Examples of the glucoamylase include the “Coclase” series manufactured by Sankyo Co., Ltd., the “Uniase” series manufactured by Yakult Yakuhin Kogyo Co., Ltd., the “Gluczyme” series manufactured by Amano Pharmaceutical Co., Ltd., and Shin Nippon Chemical Co., Ltd. Commercially available enzyme preparations for food addition, such as "Sumiteam" series manufactured by Co., Ltd., can be used.

The obtained β-glucan crude extract can be purified by a known method. For example, the crude extract is subjected to solid-liquid separation by means such as centrifugation, clarified and filtered, and concentrated if necessary. In this case, the concentration can be heated to boiling unless the pH of the liquid is acidic. This heating denatures and insolubilizes contaminating contaminant proteins and peptides. These can be removed by solid-liquid separation by means such as centrifugation. Then, after desalting by ion exchange treatment, non-fibrous substances such as monosaccharides and oligosaccharides are removed by an alcohol precipitation method, and dried to obtain a water-soluble dietary fiber mainly composed of β-glucan. be able to.

Further, the obtained crude extract of β-glucan is subjected to solid-liquid separation, clarified and filtered, followed by ultrafiltration to remove low molecular impurities and drying, to obtain the same water-soluble dietary fiber. Obtainable.

The thus obtained water-soluble dietary fiber containing β-glucan as a main component has a high purity and can be expected particularly for physiological functions. In addition, since it is tasteless and odorless, for example, it can be added to various foods and beverages such as soft drinks, jelly, pudding, soup, cookies, hamburgers,
The water-soluble dietary fiber derived from barley bran can be sufficiently ingested.

[0030]

According to the present invention, when β-glucan is extracted from barley bran, when starch is subjected to hot water treatment under pressure, gelatinization of the starch is remarkable, resulting in a high viscosity, which greatly hinders the extraction operation. In addition, in the case of alkali extraction, problems such as operations such as neutralization of the extract and treatment of the extraction residue occur. In addition, although the viscosity is reduced only by treatment with α-amylase, the production and contamination of dextrins that are not resistant to human digestive enzymes are remarkable, and the resulting extract has a reduced content of the target β-glucan. I will. Furthermore, when starchy matter is previously removed from barley bran by physical treatment such as sieving or washing, or chemical treatment such as enzyme treatment, the extract obtained therefrom has a low β-glucan content. This was thought to be because β-glucan was more present in the starch fraction and the aleurone layer.

According to the method for producing a water-soluble dietary fiber of the present invention, β-
It becomes possible to obtain glucan.

[0032]

Example 1 Transverse bran of sticky bare barley obtained from barley barley (generated at a milling yield of 65-55%: moisture 13.6)
%) For 1 kg, 10 L of hot water at 90 ° C., heat resistance α
-Amylase (Amylase “Amano” AH: manufactured by Amano Pharmaceutical Co., Ltd.) 10,000 units, and add 90 units with stirring.
Extraction was performed at 3 ° C. for 3 hours. After cooling to 50 ° C., 2,000 units of glucoamylase (Gluczyme NL4.2: manufactured by Amano Pharmaceutical Co., Ltd.) are added, and the mixture is stirred for 50 minutes.
Treated at ° C for 12 hours. This is centrifuged (5,000G
After 10 minutes), the extract was concentrated until the extract became 2 L. And centrifugation (10,000G
10 minutes) to remove insolubles, desalting with an ion exchange resin (anion, cation), adding twice the amount of ethanol, and centrifuging the resulting precipitate (1,000 G 1
Min). This was dried to obtain 89 g of a dry powder.

[0033]

Comparative Example 1 The same treatment as in [Example 1] was conducted except that the addition of glucoamylase was omitted, to obtain 150 g of an extract and dried product.

[0034]

[Comparative Example 2] Extracted raw material was used as rough milling bran of bare barley (generated at a milling yield of 100 to 82%: moisture of 11.0), and treated in the same manner as in [Example 1]. I got

[0035]

[Comparative Example 3] The extraction raw material was used as the horizontal bran of barley with bark (generated at a milling yield of 65 to 55%: moisture of 12.5%). An extract dried product was obtained.

[0036]

Example 2 Pulverized material obtained by pressing barley crushed barley (milling yield: 55% or less) was finely pulverized (water content: 11.1%) and used as an extraction raw material. ] To obtain 95 g of an extracted and dried product.

[0037]

Example 3 Long-process bran of sticky bare barley obtained by the pressing of barley pearl barley (generated at a milling yield of 82 to 65%: moisture
11.4%) 10 kg, 50 L of distilled water, heat-resistant α-amylase (Termamamil: Mitsui & Co., Ltd.) 3
0000 units were added, heated to 95 ° C., and extracted for 3 hours with stirring. After cooling to 50 ° C., glucoamylase (Uniase 30: Yakult Yakuhin Kogyo Co., Ltd.)
Was added and the mixture was treated at 50 ° C. for 12 hours with stirring. This is centrifuged (5,000 G10
), And the mixture was concentrated until the extract became 20 L. And centrifugation (10,000 G 1
0 minutes), desalting with an ion exchange resin (anion, cation), adding 2 volumes of ethanol, and centrifuging the resulting precipitate (1,000 G for 1 minute).
Collected by This was dried to obtain 1070 g of a dry powder.

Examples 1 to 3 and Comparative Examples 1 to 3
Table 3 shows the results of analyzing the components of the dry powder obtained in Step 2. Water, crude protein, and ash were determined according to standard methods. Total dietary fiber (TDF) was determined by AOAC method 995.16, β-glucan by AACC method 32-23, and digestible polysaccharide by AACC method.
It was measured by method 76-12.

[0039]

[Table 3]

[Brief description of the drawings]

FIG. 1 is a flowchart showing a milling step relating to generation of barley bran as an extraction raw material.

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Claims (6)

(57) [Claims] 1. A milling yield of 82% which is generated in a barley milling process.
The following barley bran acids, preparation of water-soluble dietary fiber composed mainly of barley bran derived β- glucan and extracting hot water with the addition of amylolytic enzymes. 2. Barley raw material having sticky barley or /
The method for producing a water-soluble dietary fiber comprising β-glucan as a main component according to claim 1 and using sticky bare barley . 3. The method for producing a water-soluble dietary fiber containing barley bran-derived β-glucan as a main component according to claim 1 or 2, wherein the amylolytic enzyme is a thermostable α-amylase. 4. The method according to claim 1, wherein the mixture of barley bran and the crude extract is treated with glucoamylase. 5. A method for producing a water-soluble dietary fiber comprising β-glucan as a main component, comprising a barley bran-derived β-glucan, wherein the extract containing a water-soluble dietary fiber obtained in any one of claims 1 to 4 is dried. 6. The extract is treated by one or more of the following steps before the extract is dried.
2. A method for producing a water-soluble dietary fiber comprising β-glucan derived from barley bran as a main component. 1 Concentration step 2 Desalination step 3 Ethanol precipitation and precipitate recovery step