JPH01263101A - Purification of alpha-cyclodextrin - Google Patents

Abstract

PURPOSE:To inexpensively produce high-purity alpha-cyclodextrin, by blending an alpha-cyclodextrin-containing mixture with a monoglyceride in the presence of water to form insoluble part and removing the monoglyceride from the insoluble part. CONSTITUTION:An alpha-cyclodextrin-containing mixture of various cyclodextrin is blended with a monoglyceride in the ratio of usually 0.2-3.0:1.0 to form insoluble part. Then the monoglyceride is removed from the prepared insoluble part by, e.g., by dispersing or dissolving the insoluble part in a substance having a higher boiling point than the monoglyceride and subjecting to steam distillation to purify the alpha-cyclodextrin. Monopalmitin, monoolein, etc., is preferable as the monoglyceride and blending of the cyclodextrin mixture and the monoglyceride is preferably carried out in a temperature range to melt the monoglycerides.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for efficiently purifying α-cyclodextrin from various cyclodextrin mixtures containing α-cyclodextrin.

[Conventional techniques and problems]

Cyclodextrins have functions such as stabilizing unstable substances, preventing volatilization of volatile substances, masking off-flavors, converting soluble and insoluble substances to 8, and acting as chemical reaction catalysts, and have many uses in food and medicine. It is being considered.

These ai are thought to be achieved by an inclusion effect in which a lipophilic substance is wrapped within the width of the steric cavity of cyclodextrin.

Cyclodextrin includes α-cyclodextrin, which has six glucose molecules linked together in a ring, and β-cyclodextrin, which has seven glucose molecules linked together in a ring shape.
Cyclodextrin, γ-cyclodextrin with 8 cyclic bonds, δ-cyclodextrin with 9 or more cyclodextrin, C-cyclodextrin, etc. are known. Also, G1-α-cyclodextrin, G, -β-cyclodextrin, G+, which has one glucose attached to cyclodextrin such as α-2β-5T-
Glucosylcylodextrin such as -r-cyclodextrin, clodextrin, G1-α-cyclodextrin in which two maltose units of glucose are combined, G, -β-cyclodextrin, maltosyl such as G□-r-cyclodextrin, etc. cyclodextrin, maltotriosylcyclodextrin such as G, -α-cyclodextrin, G1-β-cyclodextrin, G, -γ-cyclodextrin, glucosyl group, maltosyl group, G with a maltotriosyl group attached to the 2nd or higher position of cyclodextrin
+, Gl-1Gl, Gz~, G1. G,-
Branched cyclodextrins typified by cyclodextrins are known.

α-Spray 1ff1suF Risi β-Micro f
Kistrin r -cyclodextrin G! −
The production method for these cyclodextrins involves the action of an enzyme (cyclodextrin glucanotransferase) on starch to produce α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. There are methods for obtaining cyclodextrins such as Dexivar K, Dexiper 1, L1, Cell Redex CIL, Lindex-P, Toyozoline-P, etc., which are commercially available. These are mixtures of various cyclodextrins and dextrins such as α-cyclodextrin, β-cyclodextrin, T-cyclodextrin, etc., and the manufacturing method,
For example, methods for obtaining various cyclodextrin mixtures rich in α-cyclodextrin and β-cyclodextrin have been developed by selecting enzymes, etc.

Table 1 shows examples of composition analysis of typical commercial products.

Table 1 Also, as a method for producing branched cyclodextrin, a method for producing branched cyclodextrin such as maltosylcyclodextrin by attaching maltose to cyclodextrin with α-1,6 bonds using the reverse reaction of pullulanase; A method for producing maltosylcyclodextrin by allowing heat-stable pullulanase produced by Bacillus 3sp to act on a solution of maltose and cyclodextrin at high temperature for a long period of time, and a method for producing maltosylcyclodextrin using the reverse reaction of isoamylase. There is a method of manufacturing maltotriosylcyclodextrin by linking maltotriose with α-1,6 bonds, and products such as Isoelite have been commercialized. Commercially available branched cyclodextrins produced by these methods include unbranched cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and T-cyclodextrin, branched-α-cyclodextrin, branched-β-cyclodextrin, and branched-β-cyclodextrin. It is a mixture of γ-cyclodetriose, glucose, maltose, maltotriose, and dextrin. Table 2 shows an example of compositional analysis (catalog values) of a typical commercially available product ("Isoelite", manufactured by Shimizu Port Seito Co., Ltd.).

As shown in Table 2, commercially available cyclodextrins,
Branched cyclodextrin is a mixture of various cyclodextrins.

On the other hand, many attempts have been made to produce cyclodextrin with high purity. -For example, methods have been developed that combine ultrafiltration membranes and reverse osmosis membranes. Briefly, a mixture of α-1β-1γ-cyclodextrin and dextrin produced in a reaction tank is passed through an ultrafiltration membrane and sent to a reverse osmosis membrane. Unreacted dextrins other than cyclodextrin have a large molecular weight and cannot pass through the ultrafiltration membrane, so they are returned to the reaction tank and reused as raw materials for cyclodextrin production. By adding a small amount of enzyme to the reaction tank, all starch is converted to cyclodextrin, which is then concentrated using a reverse osmosis membrane. The concentrated cyclodextrin solution is sent to a crystallization tank to crystallize the less soluble β-cyclodextrin. The mother liquor is again concentrated using a reverse osmosis membrane and sent to a crystallization tank. By repeating this operation, crystals are obtained in the order of β-1α-1T-cyclodextrin, and highly purified α-1T-cyclodextrin is obtained by recrystallization.

It takes a lot of time and effort to obtain such highly pure cyclodextrin, and α-1γ-cyclodextrin, which has high solubility in water and is difficult to separate, is particularly expensive.
Compared to various cyclodextrins and mixtures of dextrins, α-cyclodextrin has several tens of times more T-
Cyclodextrins are even more expensive.

In addition, regarding cyclodextrins containing branched cyclodextrins, the solubility of various cyclodextrins in water is similar, and combined with the compatibility effect, it is extremely difficult to isolate various cyclodextrins with high purity using column chromatography, etc. It requires advanced separation technology and is very expensive. Table 3 shows the solubility of various cyclodextrins, including branched cyclodextrins, in water.

Table 3 Generally, there is selectivity between these cyclodextrins (host) and the substance to be incorporated (guest), and when the cavity size of the cyclodextrin and the steric size of the guest molecule match, the cyclodextrin is stabilized and encapsulated. It is considered easy to approach. Furthermore, the solubility of the guest often changes due to inclusion, and poorly water-soluble substances may become solubilized. This change in solubility is also related to the type of cyclodextrin, with α-cyclodextrin often forming soluble clathrates and β-cyclodextrin forming hardly soluble clathrates. Other destabilizing substance stabilizing functions, volatile substance volatilization prevention functions, off-odor masking functions, and chemical reaction catalytic functions are also expected to be related to the type of cyclodextrin. That is, depending on the desired function expression, each other's cyclodextrins, such as α-cyclodextrin and β-cyclodextrin, or α-cyclodextrin and various branched cyclodextrins, often inhibit each other's functions. In such a case, it would be ideal to use highly purified cyclodextrin alone, but as described above, this is extremely expensive and impractical.

[Means for solving problems]

In view of the above circumstances, the present inventors have conducted intensive studies on a method for inexpensively and efficiently purifying α-cyclodextrin from various cyclodextrin mixtures, and have found that various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride are purified using water. It was discovered that highly pure α-cyclodextrin could be obtained by mixing in the presence of a mixture to form an insoluble portion and then removing monoglyceride from the resulting insoluble portion, and the present invention was completed based on this finding.

That is, the present invention involves mixing various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride in the presence of water to form an insoluble portion, and then removing the monoglyceride from the resulting insoluble portion. The subject matter is a method for purifying α-cyclodextrin.

Various cyclodextrin mixtures in the present invention are α
- Anything that contains cyclodextrin to some extent can be targeted.

For example, mixtures such as α-cyclodextrin, β-cyclodextrin, T-cyclodextrin, cyclodextrin in which nine or more glucose molecules are linked in a cyclic manner, dextrin, etc. obtained by treating starch with an enzyme (cyclodextrin glucanotransferase); Method using reverse reaction of pullulanase, Bacillus
α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and various branched cyclodextrins obtained by a method in which thermostable pullulanase produced by sp. (G, -α-1G, -α-1
G, -α-1G, -β-1G2-β-1G, -β-1G
, -γ-1G2-γ-1G, -γ-, etc.) dextrin,
Examples include glucose, maltose, and mixtures of maltotrioses.

The monoglyceride in the present invention is not particularly limited, and includes, for example, saturated monoglycerides such as monobalmitin, monostearin, and monolaurin, unsaturated monoglycerides such as monoolein and monolinol, and mixtures thereof. In addition, monoglycerides are positional isomers, such as those with a fatty acid group attached to the 1-position of glycerin, and those with a fatty acid group attached to the 2-position of glycerin.
Some have a fatty acid group attached at the position, and any of them can be used. Although monoglycerides are not soluble in water, various phase diagrams can be created by changing the mixing ratio with water and changing the temperature.

For example, in the case of saturated monoglyceride, it is solid at room temperature (β
-Crystal), and when the temperature is increased, it assumes an α-gel structure, and when the temperature is further increased, it changes to a neat structure, a lamellar structure, a former 5 psrsion structure, an I/13 (H
31sotropic structure, Fluid l5otro
It takes p-ic structure etc.

In the present invention, the γ combination of monoglyceride and various cyclodextrin mixtures containing α-cyclodextrin may have any structure, but is preferably in a molten state, that is, α-gel structure, neat structure, Lamellar structure, Dtspersion structure, Viscous l5otropic structure, Flu
This is done in a state such as an id l5otropic structure.

In the present invention, the mixing ratio of various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride is determined based on the α-cyclodextrin mixture containing α-cyclodextrin.
- Depends on cyclodextrin content. That is, the molar ratio of α-cyclodextrin and monoglyceride in the cyclodextrin mixture is 0.2 to 3. o: It is preferable to mix in the range of t, o.

As described later in Examples, when a cyclodextrin mixture containing almost no branched cyclodextrin is used as a raw material, the molar ratio of α-cyclodextrin to monoglyceride in the cyclodextrin mixture is 1.
0:+, near 0, the purity of the obtained α-cyclodextrin is high. If the molar ratio of α-cyclodextrin and monoglyceride is less than o,4:i,o, α
- Some amount of β-cyclodextrin or γ-cyclodextrin is mixed into cyclodextrin. Also, α
- If the molar ratio of cyclodextrin and monoglyceride is greater than 2.0:1.0, some β-cyclodextrin will be mixed into α-cyclodextrin. On the other hand, when a cyclodextrin mixture containing mainly branched cyclodextrin is used as a raw material, a small amount of 02-α-cyclodextrin is mixed into α-cyclodextrin.

This tendency seems to become more pronounced as the molar ratio of α-cyclodextrin to monoglyceride increases. In any case, using more monoglyceride than necessary is costly and unnecessary.

In the present invention, various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride are mixed in the presence of water, and the resulting insoluble portion is obtained.
This acquisition is performed by general separation means such as vacuum filtration, centrifugation, pressure filtration, and membrane separation. In this case, the undissolved portion may be unreacted monoglyceride, a reactant between α-cyclodextrin and monoglyceride, or the like.

In the present invention, an insoluble part is generated by mixing a cyclodextrin mixture and a monoglyceride, and then the monoglyceride is removed from the insoluble part to obtain the target α-cyclodextrin. is carried out by shifting the inclusion equilibrium between α-cyclodextrin and monoglyceride.

Effective methods for shifting the inclusion equilibrium between α-cyclodextrin and monoglyceride include a method that utilizes a difference in solubility in a solvent, a method that utilizes a difference in boiling point, and the like.

Regarding methods that utilize differences in solubility in solvents, cyclodextrins are soluble in water and alcohol, and monoglycerides are insoluble in water but soluble in alcohol. On the other hand, the insoluble portion obtained by the present invention is as described above (insoluble in water, but also insoluble in alcohol.According to the study by the present inventors, the insoluble portion is soluble in pyridine, dimethylformamide, dimethyl It is soluble in sulfoxide, bormamide, etc., and is soluble in a solvent containing these solvents as the main component, such as a mixture of pyridine and water.In the present invention, the insoluble portion is a solvent containing the above solvent as the main component. and then diluted with an excess of a solvent other than the above-mentioned solvent, such as water, in order to precipitate the monoglyceride.

Next, the solution from which the monoglyceride has been removed is concentrated by heating, membrane separation, spray drying, etc. to obtain a powder. A trace amount of potassium monoglyceride remaining in the solution may precipitate during heating, but it is preferable to remove this by means of differential filtration or the like.

Next, a method of utilizing the difference in boiling points will be explained. Monoglyceride under reduced pressure (several mm 1g) 200℃~2
It is distilled by steam distillation at 50°C.

Further, it can be distilled by molecular distillation under higher vacuum conditions.

On the other hand, since cyclodextrin does not distill out under these conditions, it is possible to utilize this difference in boiling point to shift the inclusion equilibrium of the insoluble part of the present invention and remove monoglyceride from the insoluble part. In the present invention, the undissolved portion is dispersed in a suitable dispersoid having a boiling point higher than monoglyceride, such as oil or fat, and the monoglyceride is removed from the undissolved portion by steam distillation, molecular distillation, or the like. After removing the monoglyceride, α-cyclodextrin dispersed in the oil may be recovered by water extraction, fractional filtration, or the like.

The present invention is also effective in the process of producing cyclodextrin in which enzymes are used.

[Action/Effect]

According to the present invention, it becomes possible to inexpensively produce highly pure α-cyclodextrin from various cyclodextrin mixtures containing α-cyclodextrin.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited by these in any way.

Example 1 Cyclodextrin, sugar mixture [Seldefux CH-
100g of 20J (manufactured by Nihon Shokuhin Kogyo) and 100g of water
, 1.66 g of monostearin (manufactured by Riken Vitamin@, monostearin content 198%) was added and mixed at a temperature of 80 to 90° C. with a homomixer (manufactured by Tokushu Kika Kogyo ■) for 30 minutes.

Next, 2 kg of water was added to dilute the mixture to lower the viscosity of the mixture, and the undissolved portion was filtered off and washed with water. Pyridine was added and dissolved in the resulting undissolved portion, and then 20 times the volume of water of pyridine was added and mixed. Next, the precipitated monoglyceride was removed, and the aqueous phase was concentrated to obtain a powder.

Example 2 The same procedure as in Example 1 was carried out except that 3.31 g of monostearin was used.

Example 3 The same procedure as in Example 1 was carried out except that 0.66 g of monostearin was used.

Example 4 In Example 1, "Emulgy MSJ (manufactured by Riken Vitamin ■, monostearin 7)" was used instead of monostearin.
The same procedure as in Example 1 was carried out except that 1.66 g of monovalmitin (30%) was used.

Example 5 Example 1 except that 1.66 g of monoolein (98% purity) was used instead of monostearin.
I did the same thing.

Example 6 To 100 g of "Isoelite" powder product (manufactured by Shiosui Minato Refining Company, total cyclodextrin content 80%), 100 g of water and 1.3 g of monostearin were added, and at a temperature of 80 to 90 °C,
Then, the mixture was mixed for 30 minutes using a homomixer. The following is Example 1
I did the same thing.

Example 7 The same procedure as in Example 6 was carried out except that 2.5 g of monostearin was used.

Example 8 The same procedure as in Example 6 was carried out except that 12.5 g of monostearin was used.

Example 9 Add 10 times the weight of fats and oils to the undissolved portion obtained in Example 1, heat under reduced pressure (3 wmHg) to 220°C, and perform steam distillation (steam blowing water temperature 60°C) to remove monoglyceride. did.

After removing the monoglyceride by distillation, the mixture was cooled to room temperature and returned to normal pressure, and then water of the same weight as the oil and fat was added and mixed, and the aqueous phase was concentrated to obtain a powder.

Example 10 In Example 9, instead of steam distillation, 2 mmHg
Example 9 was carried out in the same manner as in Example 9, except that monoglyceride was distilled off by molecular distillation (using a falling film 2 molecular distillation machine) at 190 degrees under high vacuum.

The powder obtained in Example 1-to was subjected to liquid chromatography analysis under the following conditions.

Liquid chromatography analysis conditions: Equipment W: JASCO880-pu column; old bar Lichrosorb NH* (5
#) Eluent Niacetonitrile/Water = 60/40 Elution rate = 1 moi! /sin Detection ti: 5hodex Sε-61 The analysis results obtained are shown in Table 4. Raw material “Celdex CH-
The analysis results of 20J and "Isoelite" are also described.

As is clear from Table 4, by mixing various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride to form an insoluble portion, and then removing the monoglyceride from the resulting insoluble matter, high Purity of α-cyclodextrin can be obtained.

Claims (1)

[Claims] 1. Mixing various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride in the presence of water to form an insoluble part, and then removing the monoglyceride from the obtained insoluble part. α characterized by
- A method for purifying cyclodextrin. 2. The purification method according to claim 1, wherein the potassium monoglyceride is a saturated monoglyceride, an unsaturated monoglyceride, or a mixture thereof. 3.Claim 1 or 2, wherein various cyclodextrin mixtures containing α-cyclodextrin and monoglycerides are mixed in a temperature range where each monoglyceride melts.
Purification method as described. 4. Claim 1, wherein after dissolving the insoluble portion in a solvent containing a soluble solvent as a main component, the monoglyceride is diluted with an excess solvent in which the monoglyceride is poorly soluble or insoluble, and the resulting precipitate is removed.
5. The purification method according to claim 4, wherein the soluble solvent in the insoluble portion is at least one selected from pyridine, dimethylformamide, dimethyl sulfoxide, and formamide. 6. The purification method according to claim 1, wherein the undissolved portion is dispersed and dissolved in a substance with a boiling point higher than that of the monoglyceride, and the monoglyceride is distilled off under reduced pressure or normal pressure. 7. The purification method according to claim 5, wherein the monoglyceride is distilled off by steam distillation under reduced pressure or the like.