JPS61205494A - Production of branched dextrin and straight-chain oligosaccharide - Google Patents

Abstract

PURPOSE:A saccharified liquid containing a branched dextrin and a straight- chain oligosaccharide produced by the reaction of starch with alpha-amylase is passed through a gel-filtration agent to separate the branched dextrin from the straight-chain oligosaccharide. CONSTITUTION:A saccharified liquid containing a branched dextrin having alpha-1, 6 bond and a straight-chain oligosaccharide composed solely of alpha-1, 4 bond is produced by the reaction of starch with alpha-amylase. The saccharified liquid is fractionated with a gel filtration agent at a desired decomposition stage corresponding to the desired physical property. The gel-filtration agent is e.g. an ion exchange resin (practically having a crosslinking degree of 4-8).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selectively fractionating branched dextrins and linear oligosaccharides from starch and producing them.

Previously, the present inventors reacted liquefied starch with β-amylase to produce a saccharified solution mainly consisting of maltose and β-limited dextrin, and converted the saccharified solution into 01 (type anion exchange). We have established a method (Patent No. 1,033,249) for separately producing high-purity maltose and β-limit dextrin by bringing them into contact with a resin.

Maltose is a trisaccharide in which two D-glucose molecules are bonded with α-1,4 bonds, and has a lower sweetness than sucrose and glucose, so it is currently widely used as a reducing material in food processing. On the other hand, β-limit dextrin is a macromolecule with a branched structure and is called a branched dextrin, but due to its molecular structure, it is easily soluble in water despite being a macromolecule. can be,
It has a high viscosity and is stable, so it does not age.

Therefore, in terms of food processing, it is attracting a lot of attention as a food material that imparts elasticity and has good water retention properties.

However, recent market trends are demanding lower sweetness than maltose, and there are expectations for the physical properties of branched dextrins with even lower molecular weight than β-limit dextrins.

Starch consists of amylose, which has a linear structure in which D-glucose is polymerized with α-1,4 bonds, and dendritic amylose, which is mainly polymerized with α-1,4 bonds and branches at various points with α-1,6 bonds. It is composed of amylopectin with a structure. If β-amylase is applied to a liquefied starch having such a structure, only the outer branches of amylose, which has a linear structure, and amylopectin, which has a dendritic structure, will be attacked, and the internal structure will not be destroyed. Thus, branched dextrin with maltose and macromolecules is obtained, but when α-amylase is applied to starch, not only amylose but also α-1,4 bonds in the internal structure of amylopectin are arbitrarily cleaved.
Since α-1,6 bonds are not attacked, a saccharified solution of so-called linear oligosaccharides having a higher degree of polymerization than maltose and branched dextrins having a lower molecular weight than β-limit dextrin is obtained.

The inventors of the present invention focused on this point and in order to simultaneously satisfy the above-mentioned market demands, the inventors sought to combine linear oligosaccharides with a higher degree of polymerization than maltose and branched dextrins with a lower molecular weight than β-limit dextrin. If we can provide a method that can selectively separate starch saccharified liquid consisting of
Therefore, as a result of our studies from the viewpoint that the range of application to foods will be dramatically expanded, we have arrived at the present invention.

In the above patent, maltose produced by β-amylase of starch and β-limited dextrin, which is a macromolecule, can be effectively separated from a saccharified solution by utilizing the adsorption properties of maltose to an OH-type anion exchange resin. However, for the saccharified solution of branched dextrin, which has been reduced in molecular weight by starch α-amylase, and linear oligo￥FM, there is no longer any difference in adsorption to the OH-type anion exchange resin, and 0. It was found that effective separation was not possible depending on the type of anion exchange resin. That is, the problem is to separate the branched dextrin and linear oligosaccharide from the saccharified liquid.

Trying to find something. As a result of intensive research into a method for separating branched dextrins and linear oligosaccharides from starch decomposition products (saccharified liquid) using α-amylase, the inventors of the present invention discovered that these starch decomposition products have a branched structure. We discovered that there are differences in the internal penetration and surface sliding speed of gel filtration agents depending on the structure, whether it is a straight-chain structure or a straight-chain structure. We succeeded in effectively separating each component from the saccharified liquid. Therefore, an object of the present invention is to provide a method for effectively selectively fractionating starch from a saccharified solution mainly consisting of branched dextrins and linear oligosaccharides obtained by the action of α-amylase. do.

The present invention will be explained in detail below.

A feature of the present invention is that a saccharified solution consisting mainly of branched dextrins and linear oligosaccharides is produced by allowing α-amylase to act on starch, and then the resulting saccharified solution is brought into contact with a gel-type filtration agent. By doing so, branched dextrins and linear oligosaccharides in the saccharified liquid are selectively separated.

In the present invention, starch is treated with α-amylase to prepare a saccharification solution consisting of branched dextrins and linear oligo-tJi. By arbitrarily attacking only the α-1,4 bonds, a saccharified solution consisting of a so-called branched dextrin containing α-1,6 bonds and a linear oligosaccharide consisting only of α-1,4 bonds is obtained.

As decomposition by α-amylase progresses, each component is further reduced in molecular weight, but in the limit decomposition by α-amylase, branched dextrin with a degree of polymerization of 5 to 10, called α-limit dextrin, and α -1,4
Linear oligo I consisting mainly of bonds with a degree of polymerization of 2 to 6
! A saccharified solution consisting of

. In the present invention, the saccharified solution at each decomposition stage is flowed down from the top into a column filled with, for example, ion exchange resin as a gel filtration agent, depending on the desired physical properties, and then poured into water or the like. If the branched dextrin and linear oligosaccharide in the saccharification solution are brought into contact with an ion exchange resin by An effluent section of chain oligosaccharides is obtained.

In the present invention, in order to prepare a saccharification solution consisting of branched dextrins and linear oligosaccharides, starch is first saccharified using α-amylase.

A wide range of starch raw materials can be used, such as corn starch, potato starch, sesame starch, tapioca starch, their pregelatinized starches, and rice cake starch, which are common raw materials for producing powdered shell sugar.

Starch can be saccharified by mechanical liquefaction that involves heating, followed by the action of α-amylase, or by adding α-amylase to starch milk and directly heating it to proceed with saccharification. Depending on the purpose, saccharification can be carried out by allowing β-amylase to coexist.

Generally, the degree of decomposition of starch in the above saccharification stage is determined according to the physical properties such as viscosity and sweetness of the target product, but it is determined in the range of oEio ~ 35, taking into consideration the difficulty of subsequent separation processing. is appropriate.

The saccharification temperature of starch by α-amylase is carried out with the upper limit of the heat resistance temperature of α-amylase, but after high-temperature liquefaction, it is possible to proceed with saccharification by lowering the temperature, or it is possible to proceed with the saccharification reaction by coexisting β-amylase. Taking into account that there may be cases where the process is further advanced, the practical range of the present invention is substantially a temperature range of 45°C to 1) 0°C, and an enzyme action range of pi of 4.5 to 7.0. Become.

The degree of decomposition is controlled by the amount of enzyme added, action temperature, and action time, but the saccharification reaction can be stopped by inactivating the enzyme by heating or adding acid at the desired decomposition point during the reaction. can do.

The content of branched de- and kistrin in the saccharified solution obtained as described above varies depending on the type of starch and the degree of decomposition, but is generally in the range of about 25-50% of the solid content, with the remainder being linear oligos. It becomes sugar.

Next, the saccharified liquid obtained as described above is usually filtered to remove impurities other than carbohydrates contained in the raw materials, and if necessary, decolorized and purified at this stage, concentrated, etc. It should be understood that it is also within the scope of the present invention to subject the saccharified liquid to a pretreatment that is considered effective for step separation.

In the present invention, the gel filtration agent used to separate branched dextrins and linear oligosaccharides in the saccharification solution may be one based on commonly used dextran, agar, starch, etc., or one based on polystyrene. There are ion exchange resins with a crosslinking degree of 4.
A range of 8 to 8 is practical.

In addition, it is necessary that the particle size be uniform in the range of 40 to 80 mesh from the viewpoint of pressure loss, and the ion exchange resin is used in the salt form.

In the present invention, bringing the saccharified solution into contact with the gel filtration agent is achieved by a dynamic treatment method in which the saccharified solution is passed down or up through a fixed bed of gel filtration agents filled in a column, and the fixed bed is It is also possible to form a mixed system of various gel filtration agents.

For industrial production according to the present invention, continuous liquid flow using a pseudo-image moving bed system in which columns packed with gel filtration agents are connected in multiple stages is suitable. The number of stages of the pseudo moving bed is 4 to 6, and each stage is provided with an inlet for saccharification stock solution and water, and an outlet for branched dextrin and linear oligosaccharide, and liquid movement is performed across all stages. A circulation system is provided.

After passing the saccharification solution through all the stages, the saccharification solution is taken in and out of each stage corresponding to the separation pattern by controlling the flow rate. Another feature of the present invention is that by distributing the flow rate, selective fractionation into branched dextrins and linear oligosaccharides can be achieved almost completely.

It is economically preferable for the concentration of the saccharification stock solution used in the present invention to be as high as possible;
It is practical to set the temperature at about 60° C., since the pressure drop in the column is also related to the temperature at which the liquid passes through the column, and in order to prevent fermentation in the column. As elution water,
Commonly used water, distilled water, or highly purified ion-exchanged water is used, and the water temperature is set to the same temperature as the liquid flow temperature.

The branched dextrins separated by the present invention can be purified and concentrated using conventional methods or spray-dried to produce products. Straight-chain oligosaccharides can also be concentrated in the same way and produced by spraying. It can be dried and made into a product.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Suspend cornstarch with a moisture content of 13.5% in water and make 20"
After adjusting the pH to 6.2, add 0.1% α-amylase to starch (trade name: Termamyl, manufactured by Novo Industries) and heat-process at 105°C for 10 minutes. The mixture was cooled to 0.degree. C., 0.1% α-amylase was added, and the mixture was maintained for 4 hours to advance saccharification.

DE after reaction termination by acid addition was 22.7.

Next, the obtained saccharified liquid was subjected to conventional decolorization and purification using activated carbon and an ion exchange resin, and concentrated to a concentration of 40%.

The sugar composition of the saccharified liquid is 2% glucose and 5% maltose.
, maltotriose 15%, maltotetraose 6%,
Maltopentaose 12%, maltohexaose 20%
, 40% branched dextrin.

On the other hand, a gel type strongly acidic cation exchange resin was packed into each column of a simulated moving bed system consisting of four 1 liter columns with a diameter to height ratio of 1:2.

The ion exchange resin had a degree of crosslinking of 4, a particle size of 60 mesh, and was used in the sodium form.

A dispersion tube is installed on the internal upper surface of each column, and the inlet for the saccharification stock solution and water is connected to the outlet for the fractionated solution of branched dextrin and linear oligosaccharide via a metering pump. A solenoid valve is provided at the inlet/outlet of the liquid, and its opening/closing is controlled by a timer, and a circulation system path is provided to move the liquid through all stages via a metering pump.

The liquid passage conditions for the fractionation operation using this device were as follows.

Let us now temporarily number each column in the direction of liquid flow, Na1. m2. N13. l'h4. In this case, 100 ml of a 40% concentrated saccharification stock solution containing 40% branched string is placed in the 1st column, and 15ml of water is placed in the 1lh3 column.
0 ml of the solution was passed simultaneously for exactly 10 minutes, and the sugar solution was discharged from the columns of barrier 2 and magnetic 4 at a flow rate control ratio of 4:6 according to the component ratio of the saccharification stock solution. The branched dextrin solution was discharged from l1h2, and the linear oligosaccharide solution was discharged from the magnetic 4 column.

6 by the circulation path for exactly 30 minutes.
After moving 30 milliliters of liquid and advancing the separation pattern in each column one step, repeat the same steps as before, such as operating the liquid in and out at the position of each column that has moved one step forward, and continuing to perform circulation operations. was performed continuously.

The liquid passing temperature and the water temperature are maintained at 60°C, and each of the separated liquids is purified and concentrated to make sillage.
A portion was also pressure dried.

As a result of the analysis, the sugar composition of the fractionated branched dextrin was 89% branched dextrin, 3% maltohexaose, 2% maltopentaose, 1% maltotetraose, 2% maltotriose, and 2% maltose.

The average molecular weight of the branched dextrin was determined to be 250.
It was 000.

On the other hand, the sugar composition of the linear oligosaccharide is 3% glucose, 7% maltose, 25% maltotriose, 10% maltotetraose, 20% maltopentaose, 33% maltohexaose, and 2% branched dextrin. there were.

Example 2 1% α to starch was added to the starch saccharified solution obtained in the same manner as in Example 1.
-Amylase was added and saccharification was carried out at 65°C for 10 hours.

DE after saccharification shows 34.5, sugar composition is glucose 7
%, maltose 12%, maltotriose 21%, maltotetraose 8%, maltopentaose 27%, and branched dextrin 25%.

Next, the same procedure as in Example 1 was carried out for fractionating the sugar solution.

Since the content of branched dextrin in the saccharification stock solution was 25%, the procedure was the same as in Example 1 except that the discharge ratio of the sugar solution was controlled to be 25,775 in accordance with the composition ratio of the sugar solution.

The separated collected liquid was purified and concentrated to obtain a slag, and the branched dextrin was spray-dried.

As a result of the analysis, the sugar composition of the fractionated branched dextrin was 85% branched dextrin, 10% maltopentaose, 3% maltotriose, and 2% maltose.

On the other hand, the sugar composition of the linear oligosaccharide was 9% glucose, 15% maltose, 27% maltotriose, 1% maltotetraose, 33% maltopentaose, and 5% branched dextrin.

The average molecular weight of molecular dextrin was determined by osmotic pressure method to be 2,5
It was 00.

Claims (5)

[Claims] (1) The saccharification is carried out by allowing α-amylase to act on starch to produce a saccharified solution mainly consisting of branched dextrins and linear oligosaccharides, and then bringing the obtained saccharification solution into contact with a gel-type filter agent. A method for producing branched dextrins and linear oligosaccharides, which comprises selectively separating branched dextrins and linear oligosaccharides in a liquid. (2) Degradation rate DE of starch by α-amylase from 10 to
35. The manufacturing method according to claim (1). (3) The degree of crosslinking of the ion exchange resin as a gel type filter agent is 4.
Claim No. (1) using the range of ~8
Manufacturing method described in section. (4) Claim No. 1 in which the selective fractionation of branched dextrins and linear oligosaccharides is carried out by a simulated moving bed system.
Manufacturing method described in section. (5) The production method according to claim (4), wherein the fractionation flow rate ratio is determined in accordance with the branched dextrin content in the fractionation using the simulated moving bed method.