JP2620803B2 - Purification method of α-cyclodextrin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for efficiently purifying α-cyclodextrin from various cyclodextrin mixtures containing α-cyclodextrin.

[Conventional technology and problems]

Cyclodextrin has the functions of stabilizing unstable substances, preventing volatile substances from volatilizing, masking off-flavors, solubilizing hardly soluble and insoluble substances, and catalyzing chemical reactions. ing.

It is believed that these functions are achieved by the inclusion effect of lipophilic substances being encapsulated in the steric cavities of cyclodextrin.

Cyclodextrin includes α-cyclodextrin in which 6 glucoses are bound in a cyclic manner, and β-cyclodextrin in which 7 glucoses are bound in a cyclic manner
-Cyclodextrin, 8 cyclically linked γ-cyclodextrins, 9 or more cyclically linked δ-cyclodextrins, ε-cyclodextrins and the like are known. Further, α-, β-, G ₁ -α- cyclodextrin conjugated with one glucose to cyclodextrin of γ- like, G _{1-.beta.-cyclodextrin,} G _1-.gamma.-
Glucosyl cyclodextrin in cyclodextrin such as, G _{2-.alpha.-conjugated} two maltose glucose
Cyclodextrin, G _{2-.beta.-cyclodextrin,} G _{2-.gamma.-maltosyl} cyclodextrin in cyclodextrin such as, G _{3-.alpha.-cyclodextrin} conjugated three maltotriose glucose, G _{3-.beta.-cyclo} dextrin, G _{3-.gamma.-maltotriosyl} cyclodextrin in cyclodextrin such as glucosyl group, maltosyl group, G ₁ having a maltotriosyl group is bonded to more than 2-position of the _{cyclodextrin, G 1 -, G 1,} G 2 −, G ₂ , G
Branched cyclodextrins represented by cyclodextrins such as _2- are known.

As a method for producing these cyclodextrins, an enzyme (cyclodextrin glucanotransferase) is allowed to act on starch to produce α-cyclodextrin and β-cyclodextrin.
There are methods for obtaining cyclodextrins such as cyclodextrin, γ-cyclodextrin, etc., such as dexpearl K, dexpearl L, celldex CH, and lindex-.
P, Toyoderin-P and the like are commercially available. These are α-
Cyclodextrin, β-cyclodextrin, γ
-A mixture of various cyclodextrins such as cyclodextrins and dextrins, α-cyclodextrin-rich,
Methods for obtaining various cyclodextrin mixtures rich in β-cyclodextrin have been developed.

 Table 1 shows composition analysis examples of typical commercial products.

Further, as a method for producing a branched cyclodextrin, a method for producing a branched cyclodextrin such as maltosyl cyclodextrin by combining maltose with α-1,6 to cyclodextrin using a reverse reaction of pullulanase, A method for producing maltosyl cyclodextrin by allowing a thermostable pullulanase produced by Bacillus sp. To act on a solution of maltose and cyclodextrin at a high temperature for a long time, and converting maltotriose to cyclodextrin using a reverse reaction of isoamylase. α
There is a method of producing maltotriosyl cyclodextrin by bonding to 1,6 bonds, and isoelite and the like are commercially available. Commercially available branched cyclodextrins produced by these methods include unbranched cyclodextrins such as α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, branched-α-cyclodextrin, branched-β-cyclodextrin, and branched-cyclodextrin. It is a mixture of γ-cyclodextrin, glucose, maltose, maltotriose, and dextrin. In Table 2,
The composition analysis example (catalog value) of a typical commercial product ("Iso-Elite", manufactured by Saltwater Port Refined Sugar) is shown.

As described above, commercially available cyclodextrins and branched cyclodextrins are mixtures of various cyclodextrins.

On the other hand, many attempts have been made to produce cyclodextrin with high purity. As an example, a method combining a ultrafiltration membrane and a reverse osmosis membrane has been developed. Briefly, the α-, β-, γ-cyclodextrin and dextrin mixture produced in the reaction vessel is passed through an ultrafiltration membrane and sent to a reverse osmosis membrane. Since unreacted dextrins other than cyclodextrin have a large molecular weight and cannot pass through the ultrafiltration membrane, they are returned to the reaction tank again and reused as a raw material for producing cyclodextrin. By adding a small amount of debranching enzyme to the reaction vessel, all starch is converted to cyclodextrin and concentrated on the reverse osmosis membrane. The concentrated cyclodextrin solution is sent to a crystallization tank to crystallize β-cyclodextrin having low solubility. The mother liquor is again concentrated in a reverse osmosis membrane and sent to a crystallization tank. By this repetitive operation, crystals are obtained in the order of β-, α-, and γ-cyclodextrin, and high-purity α- and γ-cyclodextrin are obtained by recrystallization.

In order to obtain a cyclodextrin having such a high purity, much labor and labor are required, and α-, γ-cyclodextrin, which has high solubility in water and is difficult to separate, is expensive, and various cyclodextrins and dextrins are used. Compared to the mixture, α-cyclodextrin is several tens times, γ
Cyclodextrins are more expensive.

In addition, with regard to the cyclodextrin containing branched cyclodextrin, the solubility of various cyclodextrins in water is similar to each other, and the compatibility effect is combined, so that it is extremely difficult to isolate various cyclodextrins having high purity by column chromatography or the like. It requires advanced separation techniques and is very expensive. Table 3 shows the solubility of various cyclodextrins in water, including branched cyclodextrins.

There is generally a selectivity between these cyclodextrins (hosts) and the substances to be incorporated (guests), which are stabilized when the size of the cyclodextrin cavity and the steric size of the guest molecules match, and are easily included. It is believed that. In addition, the inclusion often changes the solubility of the guest, and the poorly water-soluble substance is solubilized. This change in solubility is also related to the type of cyclodextrin, and α-cyclodextrin often forms a soluble inclusion complex, and β-cyclodextrin often forms a sparingly soluble inclusion complex. Stabilization function for other destabilizing substances, volatilization prevention function for volatile substances, off-odor masking function,
It is expected that the chemical reaction catalytic function is also related to the type of cyclodextrin. That is, depending on the expression of the desired function, the cyclodextrins of each other, for example, α-cyclodextrin and β-cyclodextrin, or α-cyclodextrin and various types of branched cyclodextrins often inhibit each other's functions. In such a case, it is ideal to use a high purity cyclodextrin alone, but as described above, the price is extremely high and the practicality is poor.

[Means for solving the problem]

In view of such circumstances, the present inventors have conducted intensive studies on a method for inexpensively and efficiently producing α-cyclodextrin from various cyclodextrin mixtures.As a result, various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride were converted to water. The present inventors have found that a high degree of α-cyclodextrin can be obtained by mixing in the presence of to form an insoluble portion and then removing monoglyceride from the obtained insoluble portion, thereby completing the present invention.

That is, the present invention is characterized in that various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride are mixed in the presence of water to form an insoluble portion, and then monoglyceride is removed from the obtained insoluble portion. And a method for purifying α-cyclodextrin.

Various cyclodextrin mixtures in the present invention,
All that contain a-cyclodextrin to some extent can be of interest.

For example, a mixture of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, cyclodextrin in which nine or more glucoses are cyclically bound, and the like, which are obtained by allowing an enzyme (cyclodextrin canotrin spherase) to act on starch. Α-cyclodextrin, β-cyclo, obtained by a method utilizing a reverse reaction of pullulanase, a method in which a thermostable pullulanase produced by Bacillus sp. Dextrin, γ-cyclodextrin, various branched cyclodextrins (G ₁ -α-, G ₂ -α-, G ₃ -α-, G ₁ -β
_{-, G 2 -β-, G 3} -β-, G 1 -γ-, G 2 -γ-, G 3 -γ
-Etc.) Dextrin, glucose, maltose, a mixture of maltotrioses.

Monoglyceride in the present invention is not particularly limited,
For example, saturated monoglycerides such as monopalmine, monostearin and monolaurin, unsaturated monoglycerides such as monoolein and monolinol, and mixtures thereof can be mentioned. Monoglycerides are those having a fatty acid group at the 1-position of glycerin as positional isomers,
Some have a fatty acid group at the position, but any of them can be used. Monoglyceride does not dissolve in water, but various phase diagrams can be formed by changing the mixing ratio with water and further changing the temperature.

For example, in the case of saturated monoglyceride, it is a solid (β-crystal) at room temperature, takes an α-gel structure when the temperature is increased, and further increases the temperature, depending on the ratio with water, a neat structure, a lameu structure, a Dispersion structure, a Viscous Isotropi
Takes c structure, Fluid Isotropic structure, etc.

In the present invention, the mixture of various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride may have any structure of monoglyceride, but is preferably in a molten state, that is, α-gel structure, neat structure, lameu structure. , Dispersion structure, Viscou
s Isotropic structure, Fluid Isotropic structure, etc.

In the present invention, the mixture ratio of various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride is determined by the ratio of α in the various cyclodextrin mixtures.
-Depends on cyclodextrin content. That is, it is preferable to mix the α-cyclodextrin and the monoglyceride in the cyclodextrin mixture in a molar ratio of 0.2 to 3.0: 1.0.

As described later in Examples, when a cyclodextrin mixture containing almost no branched cyclodextrin was used as a raw material, α- in the cyclodextrin mixture was used.
The molar ratio of cyclodextrin to monoglyceride is 1.
Around 0: 1.0, the purity of the α-cyclodextrin obtained is high. When the molar ratio between α-cyclodextrin and monoglyceride is smaller than 0.4: 1.0, β-cyclodextrin and γ-cyclodextrin are slightly mixed into α-cyclodextrin. When the molar ratio of α-cyclodextrin to monoglyceride is larger than 2.0: 1.0, β-cyclodextrin is slightly mixed with α-cyclodextrin. On the other hand, when a cyclodextrin mixture mainly composed of branched cyclodextrin is used as a raw material, α2-cyclodextrin has G ₂ −
α-cyclodextrin is slightly mixed. This tendency appears to be more pronounced as the molar ratio of α-cyclodextrin to monoglyceride increases. In any case, using more than necessary monoglyceride is costly and unnecessary.

In the present invention, various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride are mixed in the presence of water to obtain an insoluble portion, which is obtained by filtration under reduced pressure, centrifugation, and pressure filtration. Separately, it is performed by a general separation means such as membrane separation. In this case, the insoluble portion may be an unreacted monoglyceride, a reactant of α-cyclodextrin and monoglyceride, or the like.

In the present invention, an insoluble portion is generated by mixing the cyclodextrin mixture and the monoglyceride, and thereafter, the monoglyceride is removed from the insoluble portion,
The desired α-cyclodextrin is obtained or the monoglyceride is removed by shifting the inclusion equilibrium between α-cyclodextrin and monoglyceride.

As a method of shifting the inclusion equilibrium between α-cyclodextrin and monoglyceride, a method utilizing a difference in solubility in a solvent, a method utilizing a difference in boiling point, and the like are effective.

Describing a method utilizing the difference in solubility as a solvent, cyclodextrin is soluble in water and alcohol, and monoglyceride is insoluble in water, but soluble in alcohol. On the other hand, the insoluble portion obtained by the present invention is insoluble in water as described above, but is also insoluble in alcohol. According to the study of the present inventors, the insoluble portion is soluble in pyridine, dimethylformamide, dimethylsulfoxide, formamide, and the like, and a solvent containing such a solvent as a main component, for example, a mixture of pyridine and water. It is soluble. In the present invention, the insoluble portion is dissolved in a solvent containing the above-mentioned solvent as a main component, and then diluted with an excess of a solvent other than the above-mentioned solvent, for example, water in order to precipitate monoglyceride.

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

Next, a method utilizing the difference in boiling points will be described.
Monoglyceride is distilled by steam distillation under reduced pressure (several mmHg) at 200 ° C to 250 ° C. Further, under a higher vacuum, distillation can be performed by molecular distillation. On the other hand, since cyclodextrin does not distill under these conditions, it is possible to remove the monoglyceride from the insoluble portion by shifting the inclusion equilibrium of the insoluble portion of the present invention by utilizing the difference in boiling points. . In the present invention, the insoluble portion is dispersed in a suitable dispersoid having a boiling point higher than that of monoglyceride, for example, fats and oils, and the monoglyceride is removed from the insoluble portion by steam distillation, molecular distillation, or the like. After removing the monoglyceride, α-cyclodextrin dispersed in the fat or oil may be recovered by water extraction, fractional filtration or the like.

The present invention is also effective in a process for producing cyclodextrin on which an enzyme is allowed to act.

[Action / Effect]

According to the present invention, high-purity α-cyclodextrin can be produced at low cost from various cyclodextrin mixtures containing α-cyclodextrin.

〔Example〕

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these.

Example 1 Cyclodextrin and sugar mixture "Celdex CH-
20 ”(100 g water from Japan Food Processing Co., Ltd., 100 g water, monostearin (manufactured by Riken Vitamin Co., Ltd., monostearin content 98
%] Of 1.66 g, and mixed at a temperature of 80 to 90 ° C. with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) for 30 minutes.

Next, 2 kg of water was added to dilute the mixture to lower the viscosity of the mixture, and then the insoluble portion was separated by filtration and washed with water. After adding and dissolving pyridine to the obtained insoluble portion, water 20 times the volume of pyridine was added and mixed. Next, after removing the precipitated monoglyceride, the aqueous phase was concentrated to obtain a powder.

Example 2 Example 1 was repeated except that 3.31 g of monostearin was used.

Example 3 Example 1 was repeated except that 0.66 g of monostearin was used.

Example 4 In Example 1, "Emulgy MS" (manufactured by Riken Vitamin Co., Ltd., Monostearin 70) was used in place of monostearin.
%, Monopartimine 30%), except that 1.66 g was used.

Example 5 The procedure of Example 1 was repeated, except that 1.66 g of monoolein (98% purity) was used instead of monostearin.

Example 6 100 g of water and 1.3 g of monostearin were added to 100 g of "Iso-Elite" powder (Saltwater Mineral Sugar Co., Ltd., total cyclodextrin content 80%), and the mixture was heated at a temperature of 80 to 90 ° C with a TK homomixer.
Mix for 30 minutes. The following was performed in the same manner as in Example 1.

Example 7 The same procedure was performed as in Example 6, 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 A 10-fold weight of fat was added to the insoluble portion obtained in Example 1, heated to 220 ° C under reduced pressure (3 mmHg), and subjected to steam distillation (water temperature for steam blowing at 60 ° C) to distill and remove monoglyceride. did.

After distilling off and removing the monoglyceride, the mixture was cooled to normal temperature and returned to normal pressure. Then, an equal amount of water was added to the fat and oil and mixed, and the aqueous phase was concentrated to obtain a powder.

Example 10 Example 9 was repeated, except that monoglyceride was distilled off at 190 ° C. under a high vacuum of 2 mmHg at 190 ° C. instead of steam distillation. The same was done.

The powders obtained in Examples 1 to 10 were subjected to liquid chromatography analysis under the following conditions.

Liquid chromatographic analysis conditions: Apparatus: JASCO 880-pu Column: Hibar Lichrosorb NH ₂ (5μ) Eluent: acetonitrile / water = 60/40 Elution rate: 1 ml / min Detector: Shodex SE-61 The results are shown in Table 4. The analysis results of “Celdex CH-20” and “Iso-Elite” as raw materials are also shown.

As is apparent from Table 4, various cyclodextrin mixtures containing α-cyclodextrin are mixed with monoglyceride to form an insoluble portion, and thereafter, by removing monoglyceride from the obtained insoluble material, a high glyceride content is obtained. Pure α-cyclodextrin can be obtained.

Claims (7)

(57) [Claims] 1. An insoluble part is produced by mixing various cyclodextrin mixtures containing α-cyclodextrin and monoglyceride in the presence of water, and then removing the monoglyceride from the obtained insoluble part. Α-cyclodextrin purification method. 2. The method according to claim 1, wherein the monoglyceride is a saturated monoglyceride, an unsaturated monoglyceride, or a mixture thereof. 3. The purification method according to claim 1, wherein the mixing of the monoglyceride with the various cyclodextrin mixtures containing α-cyclodextrin is performed in a temperature range in which each monoglyceride is melted. 4. The purification according to claim 1, wherein after dissolving the insoluble portion in a solvent containing a soluble solvent as a main component, a precipitate formed by diluting with an excess solvent in which monoglyceride is hardly soluble or insoluble is removed. Law 5. The method according to claim 4, wherein the soluble solvent in the insoluble portion is at least one selected from pyridine, dimethylformamide, dimethylsulfoxide, and formamide. 6. The purification method according to claim 1, wherein the insoluble portion is dispersed and dissolved in a substance having a boiling point higher than that of monoglyceride, and the monoglyceride is distilled off under reduced pressure or normal pressure. 7. The method according to claim 5, wherein the monoglyceride is distilled off by steam distillation or the like under reduced pressure.