JPH0692429B2 - Method for producing high-purity oligosaccharide from sugar mixture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing highly pure oligosaccharides from a sugar mixture stock solution containing oligosaccharides.

(Prior Art) Oligosaccharides have recently attracted attention as low-calorie foods, bifidobacteria growth factors, or as body materials for foods.

Such oligosaccharides are produced by various enzymatic reactions and chemical reactions in addition to naturally occurring ones. However,
These oligosaccharides contain a large amount of non-oligosaccharide components (for example, monosaccharide and disaccharide in the case of fructooligosaccharide, monosaccharide in the case of isomaltooligosaccharide). For this reason, it is necessary to remove non-oligosaccharide components to obtain high-purity oligosaccharides, and as a method therefor, a chromatography method and a crystallization method have been conventionally used.

The chromatographic method uses ion exchange or various gels to separate oligosaccharides and monosaccharides by the principle of molecular sieve by utilizing the difference in molecular weight between sugar molecules.
The crystallization method takes advantage of the difference in solubility of each sugar molecule, and gradually heats and concentrates the sugar mixture to remove the precipitated component each time.

Further, as a method for obtaining high-purity maltose by using a membrane, which is not a method for producing oligosaccharides, JP-A-48-4647 and JP-A-
The method disclosed in 52-57344 is known.

In these methods, maltose is used as a low-molecular-weight saccharide mixture to pass through a semipermeable membrane or a loose reverse osmosis membrane that permeates a solute to some extent to separate maltose from high maltose syrup.

(Problems to be Solved by the Invention) Among the above-mentioned conventional methods, chromatography is troublesome in the concentration operation after separation, and the crystallization method is disadvantageous in terms of energy cost and requires a large amount of heat for crystallization work. Since the separation performance between sugar molecules is low, the yield is poor and it is disadvantageous in terms of industrialization.

On the other hand, even if the conventional method using a membrane is used for separation and purification of oligosaccharides as they are, oligosaccharides and non-oligosaccharides (low molecular weight saccharides) have similar degrees of polymerization and do not have a large difference in molecular weight. It is not possible to separate monosaccharides or monosaccharides and disaccharides efficiently from the contained sugar mixture.
The selective separation of oligosaccharides from a sugar mixed solution in a high concentration region of w / v% (the number of sugars in 100 cc of solution) or more has become the biggest problem in the present separation and purification of oligosaccharides.

(Means for Solving the Problems) In order to solve the above problems, the present inventors have used a loose reverse osmosis membrane showing a salt inhibition rate within a predetermined range to oligosaccharides or monosaccharides and disaccharides with a high selection ratio. It can be separated from the sugar mixture. Furthermore, in the case of conventional membrane separation, the rejection rate decreases as the permeation flux increases, but when oligosaccharides are separated using the above-mentioned loose reverse osmosis membranes, permeation flux within the specified concentration range. The present invention has been made based on the finding that there is a portion in which the blocking rate also increases despite the increase in the.

That is, the gist of the present invention is that the concentration is 10 to 50 w / v% and the concentration is 10 to 7
Prepare an oligosaccharide mixed stock solution at 0 ° C and add 15 to 100 kg of this stock solution.
It is supplied to a membrane module equipped with a loose reverse osmosis membrane showing a salt inhibition rate of 10 to 70% under a pressure of f / cm ² , and monosaccharides or monosaccharides and disaccharides of low molecular weight saccharides are cross-flow filtered. It was made transparent and eliminated.

(Operation) When the stock solution is supplied to the primary side of the membrane module including the loose reverse osmosis membrane at a predetermined pressure, the low molecular weight saccharides in the stock solution permeate the membrane. Therefore, the purity of the oligosaccharide in the non-permeate can be increased without accompanying a phase change such as evaporation or coagulation or a thermal change.

(Example) Below, the Example of this invention is described based on an accompanying drawing.

FIG. 1 is an overall view of a separation device for carrying out the method of the present invention, in which 1 is a reservoir tank, 2 is a pump, 3 is a membrane module, and 4 is a thermostatic device for keeping the temperature of the stock solution in the reservoir tank constant. 5 is a water supply tank, 6 is a pressure gauge,
Reference numeral 7 is a regulating valve, 8 is a flow meter, the membrane module 3 is provided with a loose reverse osmosis membrane 9 having an intermediate property between a reverse osmosis membrane and an ultrafiltration membrane, and its form is a flat membrane type, a spiral type, A tubular type, a hollow type or the like is arbitrarily selected according to the purpose.

Using the separation apparatus as described above, for example, a stock solution containing a mixture of oligosaccharide (GFn) and a low molecular weight saccharide (G) is supplied from the reservoir tank 1 to the primary side of the membrane module 3, and the low molecular weight saccharide (G) in the stock solution is supplied. ), The loose reverse osmosis membrane 9 of the membrane module 3 is permeated and removed, and the non-permeated liquid is returned to the reservoir tank 1 again, and an amount of water corresponding to the permeated liquid is transferred from the water supply tank 5 to the reservoir tank 1. The ratio of oligosaccharide (GFn) in the stock solution is increased by the constant volume continuous filtration method.

Then, the above method is carried out under the following conditions.

The oligosaccharide mixture contained in the undiluted solution is selected from glucose, fructose, galactose, mannose and xylose containing at least one or more, and as the oligosaccharide, maltooligosaccharide, isomaltooligosaccharide, laminarioligosaccharide, cellooligosaccharide, Either galactooligosaccharide, xylooligosaccharide, fructooligosaccharide, soybean oligosaccharide or guar oligosaccharide is selected.

Concentration of sugar in the stock solution is 10-50w / v% (10-50 ° Brix)
And The reason for this will be described based on the following [Table 1] and FIG. Here, FIG. 3 is a graph in which the horizontal axis represents the concentration of the stock solution, and the vertical axis represents the permeation flux and the rejection rate.

As is clear from [Table 1] and FIG. 3, the sugar concentration was 10 w /
If it is less than v%, the permeation flux increases, but the rejection rate and selectivity (A / B) decrease, and the amount of water that permeates the loose reverse osmosis membrane becomes too large, which is disadvantageous in terms of cost. Further, when the sugar concentration exceeds 50 w / v%, the permeation flux extremely decreases and the rejection rate also largely decreases, so that the permeation amount of the target oligosaccharide increases. Therefore, the sugar concentration of the undiluted solution should be 10 to 50 w / v%, and most preferably around 30 w / v% at which the selection ratio (A / B) is maximized. In [Table 1], the permeability of the low molecular weight saccharide (G) at a concentration of 50 w / v% exceeds 100, because the low molecular weight saccharide has a larger amount than the water molecule before the loose reverse osmosis membrane. Indicates that it has been transmitted.

The temperature of the stock solution should be 10-70 ℃. This is because if the temperature is lower than 10 ° C., the viscosity of the undiluted solution becomes too high and it becomes difficult to supply it by a pump, while if it exceeds 70 ° C., there arises a problem in the heat resistance of the components constituting the membrane module 3.

The pressure of the undiluted solution supplied to the membrane module 3 (pressure on the primary side of the membrane module) is set to 15 to 100 kgf / cm ² . The reason for this is that when the pressure is less than 15 kgf / cm ² , it is not possible to overcome the osmotic pressure in the above concentration range, it is impossible to permeate low molecular weight sugars, and when it exceeds 100 kgf / cm ^2. This is because there is a possibility that continuous filtration may not be possible in terms of durability of the membrane module.

As the loose reverse osmosis membrane, one having a salt inhibition rate of 10 to 70% is used. The above-mentioned salt rejection rate is because it is possible to separate and remove only monosaccharides or only monosaccharides and disaccharides from the stock solution by using a loose reverse osmosis membrane having a rejection rate in this range. Incidentally, even if only monosaccharides or only monosaccharides and disaccharides are used, the permeate contains oligosaccharides because it is a filtration system.
The point is the selection ratio (A / B). Then, the salt inhibition rate of the loose reverse osmosis membrane is changed within the above range depending on the kind of the target oligosaccharide. For example, in the case of obtaining fructooligosaccharide, a loose reverse osmosis membrane with a lower inhibition rate is selected to remove mainly monosaccharides and disaccharides, and in case of obtaining isomaltooligosaccharide, a loose reverse osmosis membrane with a higher inhibition rate is used. Select and mainly remove monosaccharides.

Toray SU-200, DDSHC-50, Nitto Denko NTR-7250, NTR-7450, Mitsubishi Rayon MRG-5, Desalination G-10 etc. are specific examples of loose reverse osmosis membranes that satisfy the above requirements.

FIG. 2 shows an overall view of another separation apparatus for carrying out the method of the present invention. In the apparatus shown in FIG. 1, the non-permeated liquid is returned to the reservoir tank 1 again by a circulation system. However, in the device shown in FIG. 2, the membrane module 3
Are arranged in series to supply the non-permeate of the upstream membrane module to the downstream membrane module.
Even in this embodiment, water is supplied from the water supply tank 5 in order to maintain the sugar concentration of the liquid supplied to each membrane module 3 within a certain range.

Next, specific results of monosaccharide removal as Example 1 and monosaccharide and disaccharide removal as Example 2 will be shown.

[Example 1-Removal of monosaccharide] (1) Commercially available acid saccharified water candy (DE; 50-60, DE = dextrose equ)
Removal of monosaccharide from ivarent) Commercially available water candy (85 ° Bx) is diluted to 30 ° Bx with reverse osmosis membrane treated water (hereinafter referred to as RO), and pressure is 30kgf / at a temperature of 50 ° C.
Constant volume continuous filtration was carried out under the condition of cm ² .

(2) Removal of monosaccharide from sugar mixture containing maltooligosaccharide Commercially available isomalt 500 (75 ° Bx) was diluted to 30 ° Bx with RO water, and constant volume continuous filtration was carried out under the same conditions as in (1).

(3) Removal of Monosaccharide from Sugar Mixture Containing Cellooligosaccharide Using acid hydrolyzate of cellulose (30 ° Bx), constant volume continuous filtration was carried out under the same conditions as in (1).

(4) Removal of monosaccharides from sugar mixture containing xylooligosaccharides Xylan acid hydrolyzate (50 ° Bx) was diluted to 30 ° Bx with RO water, and constant volume continuous filtration was performed under the same conditions as (1). did.

(5) Removal of monosaccharide from sugar mixture containing lamina oligosaccharide Acid hydrolyzate of curdlan (50 ° Bx) in RO water at 30 ° Bx
The mixture was diluted with water and subjected to constant volume continuous filtration under the same conditions as in (1).

The results of Example 1 are shown in [Table 2].

In [Table 2], for example, if the ratio of concentrated sugar (45.9) is multiplied by the recovery ratio (68.5), the ratio in the undiluted solution (16.6) should be obtained. It's more than this. This is because the relative proportions are accurate because the quantitative analysis was performed by liquid chromatography, but there was some error in the absolute amounts.

[Example 2-Removal of monosaccharide and disaccharide] (1) Removal of monosaccharide and disaccharide from sugar mixture containing fructooligosaccharide Commercially available Neo Sugar G (75 ° Bx) was diluted to 30 ° Bx with RO water. Then, constant volume continuous filtration was carried out at a temperature of 50 ° C. and a pressure of 30 kgf / cm ² .

(2) Removal of monosaccharides and disaccharides from a sugar mixture containing soybean oligosaccharide Commercial soybean oligosaccharide (77.7 ° Bx) was diluted to 30 ° Bx with RO water, and a constant volume was maintained under the same conditions as (1). Filtration was performed.

(3) Removal of monosaccharide and disaccharide from saccharide mixture containing galactooligosaccharide Commercially available galactooligosaccharide (72 ° Bx) was diluted to 30 ° Bx with RO water, and constant volume continuous filtration was performed under the same conditions as (1). Carried out.

In addition, in Example 2, two kinds of experiments were performed with different constant volume continuous filtration times for each oligosaccharide, one was conducted until the ratio of monosaccharides became 0, and the other was monosaccharides. I tried to do it until it remained a little. The results are shown in [Table 3] below.

(Effect of the invention) As is clear from the above description, according to the present invention, a monosaccharide or a disaccharide and a disaccharide can be efficiently separated and removed from a sugar stock solution containing various oligosaccharides, and the engineering can be performed at low cost. A highly pure oligosaccharide can be produced.

[Brief description of drawings]

1 and 2 are overall schematic views of a separation apparatus used for carrying out the method of the present invention, and FIG. 3 is a graph showing the relationship between the sugar concentration of the undiluted solution, the permeation flux and the inhibition rate. In the drawings, 1 is a reservoir tank, 2 is a pump, 3 is a membrane module, 4 is a thermostatic device, 5 is a water supply tank, and 9 is a loose reverse osmosis membrane.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Hirayama 5-33-17 Shonan Takatori, Yokosuka City, Kanagawa Prefecture (56) References Membrane: Vol. 3, No. 3. Pp. 159-167 (1986)

Claims (12)

[Claims] 1. A method for producing a high-purity oligosaccharide from a sugar mixture, which comprises supplying a stock solution containing oligosaccharides to a membrane module to permeate and remove low-molecular-weight saccharides in the stock solution. 50w / v%, temperature 10-70 ° C, a loose reverse osmosis membrane showing salt rejection of 10-70% was installed in the membrane module, and the pressure on the primary side of the loose reverse osmosis membrane was 15-70%. A method for producing a high-purity oligosaccharide from a sugar mixture, which is 100 kgf / cm ² . 2. The non-permeate liquid which has been prevented from permeating the loose reverse osmosis membrane is returned to the stock solution, and an amount of water corresponding to the amount of the permeate solution is added to the stock solution. A method for producing a high-purity oligosaccharide from the sugar mixture according to the item (1). 3. A plurality of the membrane modules are provided in series,
The non-permeate of the upstream membrane module is supplied to the downstream membrane module.
A method for producing a high-purity oligosaccharide from the sugar mixture according to 1. 4. The sugar molecule constituting the stock solution is glucose,
The method for producing a high-purity oligosaccharide from a sugar mixture according to claim (1), which comprises at least one sugar residue selected from fructose, galactose, mannose and xylose. 5. The oligosaccharide in the stock solution is maltooligosaccharide,
Isomalto-oligosaccharide, laminari-oligosaccharide, cellooligosaccharide, galactooligosaccharide, xylo-oligosaccharide, fructooligosaccharide, soybean oligosaccharide or guar-oligosaccharide, and a high-purity oligo from the sugar mixture according to claim (1). Method for producing sugar. 6. The method for producing a high-purity oligosaccharide from a sugar mixture according to claim 1, wherein the low-molecular-weight saccharide that is removed by permeating the loose reverse osmosis membrane is mainly a monosaccharide. 7. The high-purity oligo from the sugar mixture according to claim 1, wherein the low-molecular weight saccharide that is removed by permeating the loose reverse osmosis membrane is mainly a mixture of monosaccharide and disaccharide. Method for producing sugar. 8. The main component of the obtained high-purity oligosaccharide is composed of two or more sugar residues, and the sugar residue is at least one of glucose, fructose, galactose, mannose and xylose. A method for producing a high-purity oligosaccharide from the sugar mixture according to claim (6). 9. The main component of the obtained high-purity oligosaccharide is any of maltooligosaccharide, isomaltooligosaccharide, laminari oligosaccharide, cellooligosaccharide, xylooligosaccharide, galactooligosaccharide, fructooligosaccharide, soybean oligosaccharide or guarigosaccharide, and The method for producing a highly pure oligosaccharide from a sugar mixture according to claim 6, wherein each oligosaccharide is composed of two or more sugar residues. 10. The main component of the obtained high-purity oligosaccharide is composed of three or more sugar residues, and the sugar residue is glucose,
It is at least 1 sort (s) of fructose, galactose, mannose, and xylose, The manufacturing method of the high purity oligosaccharide from the sugar mixture of Claim (7) characterized by the above-mentioned. 11. The main component of the obtained high-purity oligosaccharide is maltooligosaccharide, isomaltooligosaccharide, laminari-oligosaccharide,
A cellooligosaccharide, a xylooligosaccharide, a galactooligosaccharide, a fructooligosaccharide, a soybean oligosaccharide or a guar oligosaccharide, and each oligosaccharide is composed of three or more sugar residues. A method for producing a high-purity oligosaccharide from a sugar mixture. 12. The method for producing high-purity oligosaccharide from a sugar mixture according to claim 7, wherein the obtained high-purity oligosaccharide has a fructo-oligosaccharide content of 75 w / v% or more.