JPH0154040B2 - - Google Patents

Description

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

Conventional Technical Background First, the present inventors caused β-amylase to act on liquefied starch to generate a saccharified solution mainly consisting of maltose and β-limitodextrin, and converted the saccharified solution into an OH-type anion exchange resin. A method for separating and producing high-purity maltose and β-limited dextrin by contacting them (Patent No.
1033249) was established.

Maltose consists of two molecules of D-glucose, α-1,
Since it is a 4-linked disaccharide and has a lower sweetness than sucrose and glucose, it is currently widely used as a sweetening 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. It has a high viscosity, is stable, and does not age. Therefore, in 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-limited dextrins.

Starch consists of amylose, which has a linear structure in which D-glucose is polymerized with α-1,4 bonds, and mainly α-1,
It is composed of amylopectin, which is polymerized with 4 bonds and has a dendritic structure with α-1,6 bonds in various places. When 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, are attacked, and the internal structure is not destroyed. As shown, maltose and macromolecular branched dextrin are obtained, but if α-amylase is applied to starch, not only amylose but also α- of the internal structure of amylopectin can be obtained.
Since 1,4 bonds are arbitrarily cleaved and α-1,6 bonds are not attacked, this is a saccharified solution of so-called linear oligosaccharides, which have a higher degree of polymerization than maltose, and branched dextrins, which have a lower molecular weight than β-limit dextrin. will be obtained.

The present inventors focused on this point, and in order to simultaneously satisfy the above-mentioned market demands, we developed a combination of a linear oligosaccharide with a higher degree of polymerization than maltose and a branched dextrin with a lower molecular weight than β-limited dextrin. If we can provide a method that can selectively separate starch saccharified liquids consisting of several types, it will be possible to meet the market demands, and the scope of application to food products will therefore be dramatically expanded. As a result of further investigation, 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, are 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 and linear oligosaccharide, which have been reduced in molecular weight by starch α-amylase, there is no longer any difference in adsorption to OH type anion exchange resin, and OH 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.

Problems to be Solved by the Invention 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 present inventors found that these starch decomposition products We discovered that there are differences in the internal penetration of gel filtration agents and the sliding speed on the surface depending on the structure, whether it has a branched structure or a linear structure, and we decided to take advantage of this difference. As a result, we succeeded in effectively separating branched dextrins and linear oligosaccharides into their respective components from the saccharified liquid. Therefore, the present invention provides starch with α-
The object of the present invention is to provide a method that can effectively selectively separate branched dextrins and linear oligosaccharides from a saccharified solution obtained by the action of amylase.

The present invention will be explained in detail below.

Structure of the Invention The present invention is characterized in that a saccharified solution consisting mainly of branched dextrins and linear oligosaccharides is produced by causing α-amylase to act on starch, and then the resulting saccharified solution is brought into contact with a gel-type filtering agent. Particularly, the objective is to selectively separate branched dextrins and linear oligosaccharides in the saccharified liquid.

In the present invention, starch is treated with α-amylase to prepare a saccharified solution consisting of branched dextrins and linear oligosaccharides. Only the α-1,4 linkages of amylopectin are optionally attacked to obtain a saccharified solution consisting of so-called branched dextrins containing α-1,6 linkages and linear oligosaccharides consisting only of α-1,4 linkages.

As decomposition by α-amylase progresses, each component becomes lower in molecular weight, but α
- In limit decomposition by amylase, saccharification consists of a branched dextrin with a degree of polymerization of 5 to 10, called α-limit dextrin, and a linear oligosaccharide with a degree of polymerization of 2 to 6, consisting only of α-1,4 bonds. A liquid is obtained.

Means for Solving the Problems In the present invention, the saccharified solution at each decomposition stage is allowed to flow down from the top into a column filled with, for example, ion exchange resin as a gel filtration agent, and then water etc. If the branched dextrin and the linear oligosaccharide in the saccharification solution are brought into contact with an ion exchange resin, a difference will occur in the flow of the branched dextrin and the linear oligosaccharide, and the branched dextrin will be detected in the initial flow of the effluent, and then directly 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, first
- Carry out saccharification of starch by amylase.

A wide range of starch raw materials can be used, including corn starch, potato starch, sweet potato starch, tapioca starch, their pregelatinized starches, and rice cake starch, which are common raw materials for producing starch 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 of the target product, such as viscosity and sweetness, but it is determined within the range of DE10 to DE35, 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.
After high-temperature liquefaction, it is possible to proceed with saccharification by lowering the temperature, and if we also take into account that the saccharification reaction may proceed with β-amylase coexisting, it is practically possible to proceed with saccharification at temperatures between 45℃ and 110℃. Temperature range or PH is
The action range of the enzyme of 4.5 to 7.0 is the practical range of the present invention.

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

The content of branched dextrin in the saccharified solution obtained as described above varies depending on the type of starch and the degree of decomposition, but it is generally in the range of about 25 to 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. Among them, ion exchange resins having a degree of crosslinking of 4 to 8 are particularly practical.

In addition, it is necessary for the particle size to be uniform in the range of 40 to 80 mesh from the viewpoint of pressure loss.
In addition, 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 through a fixed bed of gel filtration agents filled in a column by descending or rising. The layer can also be formed from a mixed system of various gel filtration agents.

For industrial production according to the present invention, continuous flow using a simulated 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 or more, and each stage is provided with an inlet for the 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 it is possible to almost completely selectively separate branched dextrins and linear oligosaccharides by distributing the discharge flow rate.

Although 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 realistic to set the concentration to about 40% in consideration of the pressure drop in the column. It is also related to temperature, and from the viewpoint of preventing fermentation in the column, it is preferable to set the temperature to about 60°C. As the elution water, commonly used water, distilled water, or highly purified ion-exchanged water is used, and the temperature of the water is set to be the same as the liquid passage temperature.

The branched dextrins separated according to 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 to produce products. It can be made into a product by drying or spray drying.

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

Example 1 Cornstarch with a moisture content of 13.5% was suspended in water.
After adjusting the pH to 20° Baume and pH 6.2, add 0.1% starch α-amylase (trade name: Terma Milnovo Industries Co., Ltd.) and heat it to 105°C for 10 minutes. The mixture was cooled to 65°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 is subjected to normal decolorization and purification using activated carbon and ion exchange resin to reduce the amount to 40%.
It was concentrated to a concentration of .

The sugar composition of the saccharified solution was 2% glucose, 5% maltose, 15% maltotriose, 6% maltotetraose, 12% maltopentaose, 20% maltohexaose, and 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.

Now, suppose we number each column in the direction of liquid flow and call it No. 1, No. 2, No. 3, No. 4.
40% containing 40% branched dextrin in No. 1 column
100 ml of concentrated saccharification stock solution and 150 ml of water were simultaneously passed through the No. 3 column for exactly 10 minutes, during which time the flow rate from the No. 2 and No. 4 columns was adjusted according to the component ratio of the saccharification stock solution. The sugar solution was discharged at a control ratio of 4:6. The branched dextrin solution was discharged from the No. 2 column, and the linear oligosaccharide solution was discharged from the No. 4 column.

Then, after moving 630 milliliters of liquid through the circulation path for exactly 30 minutes to advance the separation pattern in each column by one step,
As in the previous case, the liquid was introduced and removed at each column position moved forward by one step, and the circulation operation was subsequently repeated.

The liquid passing temperature and the water temperature were maintained at 60°C, and each of the separated liquids was purified and concentrated to form syrup, and a portion was spray-dried.

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

The average molecular weight of the branched dextrin moiety was 25,000 as determined by GPC method.

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

Example 2 A starch saccharification solution obtained in the same manner as in Example 1 was added with 1% α-amylase based on starch, and saccharified at 65°C for 10 hours.

The DE after saccharification is 34.5, and the sugar composition is 7% glucose, 12% maltose, and 21% maltotriose.
%, 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 discharge ratio of the sugar solution was adjusted according to the composition ratio of the sugar solution.
The process was the same as in Example 1 except that the time was controlled to be 25:75.

The separated collected liquid was purified and concentrated to obtain syrup, 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,
It contained 3% maltotriose and 2% maltose.

On the other hand, the sugar composition of linear oligosaccharides is glucose 9%,
The contents were 15% maltose, 27% maltotriose, 11% maltotetraose, 33% maltopentaose, and 5% branched dextrin.

The average molecular weight of the branched dextrin moiety was 10,000 as determined by GPC method.

Claims (1)

[Scope of Claims] 1. A method of producing a saccharified liquid mainly consisting of branched dextrins and linear oligosaccharides by causing α-amylase to act on starch, and then bringing the obtained saccharified liquid into contact with a gel-type filter agent. Therefore, a method for producing branched dextrins and linear oligosaccharides, which comprises selectively separating branched dextrins and linear oligosaccharides in the saccharified liquid. 2 Starch degradation rate DE by α-amylase is 10
35. The manufacturing method according to claim 1, which ranges from 1 to 35. 3. The manufacturing method according to claim 1, in which an ion exchange resin having a crosslinking degree of 4 to 8 is used as the gel type filter agent. 4. The production method according to claim 1, wherein the selective fractionation of branched dextrins and linear oligosaccharides is carried out by a simulated moving bed method. 5. The manufacturing 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.