JP3096503B2 - Method for producing erythritol crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing erythritol crystals by a fermentation method, and in particular, has a pleasant sweet taste similar to that of sucrose without a pungent odor like a drug.
The present invention relates to a method for producing edible erythritol crystals having a particularly favorable cool sweetness and suitable for eating and drinking.

[0002]

BACKGROUND OF THE INVENTION Erythritol has attracted attention as a low-calorie sweetener (sweetness is about 0.8 times that of sucrose).
Erythritol is produced by using glucose as a raw material in an aqueous medium and using Trichosporonoides mega
Chileensis SN-G42 strain (former name: Aureobasidium)
Ium sp. ( SN-G42 strain) (JP-A-3-4309 )
No. 1), Moniliella tomentosa var polynis (see JP-A-60-110298), and Candida lipolytica (Japanese Patent Publication No. 47-41549).
In general, a method of performing aerobic culturing in the presence of a yeast-like fungus represented by Japanese Patent Application Laid-Open No. H10-216, etc.). Erythritol crystals were produced by removing bacterial cells from a culture solution containing erythritol obtained by culturing, desalting and decolorizing with an ion-exchange resin, activated carbon, or the like, and then crystallizing the same. However, in the conventional method, a small amount of chemical-like odor components produced in the fermentation step are not sufficiently removed particularly in the purification system, but are supplied to the crystallization step. Erythritol crystals having a favorable cool sweetness were not obtained.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and has a odorless and more sweet flavor similar to sucrose from a liquid containing erythritol obtained by a fermentation method. It is an object of the present invention to provide a method for producing erythritol crystals having a remarkably favorable cool sweetness.

[0004]

Means for Solving the Problems The present inventors have made various studies to achieve the above object, and as a result, have found that the above problem is caused by acetoin which is a by-product of erythritol fermentation. By keeping the acetoin concentration in the erythritol-containing liquid in the precipitation vessel in a specific range, it was found that erythritol crystals having a particularly preferable refreshing sweetness without a chemical-like pungent odor were obtained, and the present invention was reached. That is, the present invention relates to a method for producing erythritol crystals from an erythritol-containing solution obtained from a fermentation method, wherein the acetoin concentration when crystallizing erythritol crystals from a slurry solution containing erythritol crystals is 1 to 20.
The present invention relates to a method for producing erythritol crystals, characterized in that the weight is ppm.

Hereinafter, the present invention will be described in detail. As a method for obtaining erythritol by fermentation, a conventional method can be appropriately adopted. For example, using glucose as a raw material, Trichosporonoi
Death megatiliensis SN-G42 strain (formerly: Oh
Leobasidium sp. An erythritol-containing fermented solution can be obtained by performing aerobic cultivation in the presence of yeast-like molds represented by S. cerevisiae SN-G42) , Monilieratantsa var polynis, Candida lipolytica, and the like. According to the prior art, erythritol crystals were obtained by separating cells from the erythritol-containing solution obtained by fermentation, then desalting and decolorizing the solution with an ion exchange resin or activated carbon, and concentrating and crystallization. However, impurities are mixed into the crystals in this crystallization step, and a pungent odor like a medicine remains in the obtained crystals. The cause of the unpleasant chemical-like irritating odor given to the product crystals is that trace amounts of acetoin generated in the fermentation system are not sufficiently removed in the purification process,
It is supplied to the crystallization process and is mixed into the product crystal, which significantly reduces the quality of the product.

Acetoin is used in various fermented products, for example, 18 to 26 ppm for beer, 4 to 30 ppm for sake, 20 ppm or less for wine, and 300 to 400 ppm for cider.
ppm and vinegar are known to contain 800 ppm or less. These acetoins are by-produced together with 2,3-butanediol. However, in the above-mentioned fermented products, acetoin is well harmonized with other aroma components and does not pose a problem as a chemical-like pungent odor. On the other hand, as a result of quantitative analysis of erythritol crystals by acetoin by the gas chromatography method, even a problematic crystal having a pungent odor like a chemical was not detected below the lower limit of analysis (1 ppm as a 20% by weight erythritol aqueous solution). Nevertheless, erythritol crystals do not contain any other odor components, so they contain only a very small amount of acetoin, which is difficult to quantitatively analyze. Is considered to be emphasized as a pungent odor.

[0007] The concentration of acetoin produced in the fermentation solution varies depending on the culture conditions, but is about 25 to 300 ppm by weight. When this fermentation broth is purified and crystallized by a conventional method,
Acetoin is mixed with other impurities in the crystallization system in a small amount into the crystal, and an unpleasant chemical-like irritating odor is generated in the erythritol crystal.

[0008] In order to solve this problem, a method for effectively removing acetoin in the purification step and a method for preventing acetoin from being mixed in the crystallization step were studied diligently. The following (1)-
The four methods of (4) are to produce erythritol crystals having a pleasant sweet flavor that is more similar to sucrose without a chemical-like pungent odor, and that has a remarkably preferable cool sweetness.
It is effective and is given as an example of a preferred method.

(1) Method by Evaporation and Separation of Acetoin The boiling point of acetoin is 148 ° C. (THE MERCK
INDEX, NINTH EDITION), but in the concentration step, it moves to the condensed water side, so that it can be evaporated together with water. In order to carry out this phenomenon efficiently, water is added again directly to the erythritol concentrate to dilute it,
In reconcentration, acetoin is removed by evaporation together with water. However, this is not practical because it increases the number of steps. The following method is mentioned as an alternative method. In either method, the erythritol-containing liquid is sufficiently diluted with water.

When separating cells from the culture solution, sufficient water (0.5 to 2 volumes of wet cells) for washing the separated wet cells is used.
Erythritol lost together with the wet cells is recovered as much as possible by performing water washing 1 to 3 times, and the cell washing solution is added to the culture supernatant after the cell separation. A method of evaporating and removing acetoin in a culture solution by positively increasing the amount of evaporating water during the concentration in the step.

The crystallization slurry is separated into a crystallization mother liquor and wet crystals by a centrifugal separator, and a washing liquid discharged when the wet crystals are washed with water is returned to a concentration step upstream of the crystallization step, or A method in which acetoin in an erythritol-containing solution is removed by evaporation by adding to a crystallization mother liquor to increase the amount of evaporated water in a concentration step. In this method, it is preferable to use a large amount of washing water in order to wash off the mother liquor adhering to the wet crystals as much as possible and obtain high-purity crystals. However, because of the high solubility of erythritol in water, the use of large amounts of water leads to dissolution loss of the crystals. The amount of the washing water used for the wet crystals is preferably 0.2 to 1.5 times the weight of the wet crystals.

A method disclosed in JP-A-1-199583. This method is very effective in increasing the amount of evaporated water in the concentration step. That is, according to the method disclosed in the publication, first, the cells are removed from the erythritol fermentation broth, followed by concentration and chromatographic separation. Since the erythritol-containing fraction is diluted by the chromatographic separation, it needs to be concentrated again during crystallization, and this two-stage concentration is extremely effective in removing odor components.

In addition to the above-mentioned method, water is used for some purpose (for example, erythritol recovery), and the recovered liquid is added to the erythritol-containing liquid in the purification step to increase the amount of evaporated water in the concentration step. Any method may be used as long as acetoin is removed by evaporation together with the evaporation of water.

As a result of various studies on the allowable concentration of acetoin given to the product crystals, it was found that if the acetoin concentration of the slurry containing crystals in the crystallizer was 20 ppm by weight or less, crystallization was carried out from the erythritol-containing solution. The product crystals were found not to exhibit a pungent odor like a drug to the general public. In terms of product odor, the lower the acetoin concentration in the liquid in the crystallizer, the lower the product odor, but in order to do so, a large amount of water is added in some way during the purification process.
It is necessary to increase the amount of evaporated water in the concentration step. However, this undesirably increases the heat source usage more than necessary. When the lower limit of the acetoin concentration in the crystallization system in which erythritol crystals are obtained so that even a person who is extremely sensitive to odor is not felt at all is obtained, it is sufficient to lower the acetoin concentration of the liquid in the crystallization can to 1 ppm. A further decrease in the acetoin concentration causes an unnecessary increase in energy consumption, which is not preferable.

(2) Method by Adjusting Erythritol Concentration of Liquid in Crystallization Can The crystallization while keeping the erythritol concentration high in the crystallization step leads to an increase in the amount of evaporating water in the concentration step, and the acetoin concentration Causes a decrease. However, as the amount of evaporating water in the concentration step is increased to increase the acetoin removal rate, the amount of erythritol crystals deposited in the crystallization step is increased, and it becomes difficult to transport the crystallization slurry through piping.
Further, under such conditions, aggregated crystals in which the fine crystals adhere to each other are likely to be generated, which causes a problem that these aggregated crystals are easily broken in a centrifugal separation step and a drying step of the crystal. On the other hand, when the erythritol concentration in the liquid in the crystallizer is low, the amount of water to be evaporated is small, and the acetoin removal rate is low. Also, the amount of precipitated crystals in the crystallization can is reduced, which is not preferable. In consideration of these points, the erythritol content in the slurry liquid containing the crystals of the liquid in the crystallization can is reduced to 40 to 40%.
Preferably, it is adjusted to 65% by weight. The crystallization method may be either batch crystallization or continuous crystallization. In the case of batch cooling crystallization, since the composition of the crystallization can supply liquid and the composition of the in-can liquid are the same, the erythritol content of the crystallization can supply liquid may be set to 40 to 65% by weight. If continuous evaporation crystallization may be holding the content of the total erythritol including precipitated crystals 40-6 5 by weight% with respect to slurry the total amount of the crystallizer.

(3) Method of Purging the Crystallized Mother Liquid The method of positively removing acetoin in the purification system includes the above-mentioned evaporation separation method. When part or all of the crystallization mother liquor is returned to the upper crystallization step, acetoin accumulated in the crystallization system needs to be purged together with other impurities as part of the crystallization mother liquor. At that time, including the multi-stage crystallization, the acetoin concentration of the liquid in the crystallization can to obtain the product directly was 1 to
The crystallization mother liquor may be purged so as to be in the range of 20 ppm by weight. However, purging more than necessary in order to lower the acetoin concentration in the crystallization vessel is not preferable because it causes a decrease in the erythritol recovery rate in the purification system and an increase in energy consumption.

(4) Method of Desalting and Decolorizing the Crystallized Mother Liquor with Ion Exchange Resin The crystallization operation is performed by setting the acetoin concentration of the liquid in the crystallizer to 1 to 20 ppm by weight according to the above methods (1) to (3). In the multi-stage crystallization, the mother liquor of the crystallization is concentrated again, and a product crystal is obtained by crystallization. At this time, the crystallized mother liquor is again desalted and decolorized in an ion-exchange resin tower, and concentrated and crystallized, so that it has a pleasant sweet taste similar to sucrose, without a pungent odor like a drug, and is a remarkably preferable cooling. A product crystal with a sweet taste is obtained. Even if the crystallization mother liquor is simply concentrated and crystallized again, the acetoin concentration of the solution in the crystallization can is 1 to 20.
By adjusting to ppm by weight, it is possible to produce odorless crystals as product crystals, but it has been found that a difference occurs in the sweet flavor. When the crystallized mother liquor is treated again with the ion exchange resin, it has a more pleasant sweet flavor similar to that of sucrose, and erythritol crystals having a remarkably preferable cool sweetness can be obtained. The apparatus for desalting the crystallized mother liquor may be provided separately from the apparatus for desalting the fermented liquid, or may be used together with a delay in the passage of the liquid. Furthermore, if the erythritol purity per dissolved solid content in the crystallized mother liquor is high, the cells may be mixed with the supernatant liquid from which the cells have been separated and subjected to desalting simultaneously.

According to the acetoin concentration in the fermentation broth, the above methods (1) to (4) are arbitrarily combined so that the acetoin concentration in the crystallizer can be 1 to 20 ppm by weight.
As a result, erythritol crystals having a sweet taste similar to that of sucrose and having a remarkably preferable cool sweetness without a pungent odor like a medicine can be obtained.

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to the following Examples without departing from the scope of the invention.

Example 1 Purified glucose 300 g / l, yeast extract 2.5 g / l,
Place 0.61 each of a sterilized seed medium having a composition of malt extract 2.5 g / l and polypeptone 5 g / l in three 31 Erlenmeyer flasks, and place them in Trichosporonoides megatiliensi.
Strain SN-G42 (former name: Aureobasidium SN
(G42 strain) was inoculated and shake-cultured at 30 ° C. for 96 hours to obtain a preculture solution. In a sterilized 50 l jar, individually sterilized purified glucose (glucose purity 95% by weight)
A solution in which 11.16 kg was dissolved and 1.87 kg of corn steep liquor (CSL) were added. Then, 1.62 l of a preculture solution obtained by shaking culture was added, and the pH was adjusted to 4.2.
Main culture was performed. The liquid volume at the start of the main culture is 26.7 l
The composition is glucose 397 g / l, CSL 70 g
/ L. The main culture was performed at a stirring speed of 600 rpm, an air supply speed of 0.5 vvm, and a temperature of 35 ° C. for 96 hours. The liquid volume at the end of the culture was 24.2 l, the composition was 214.3 g / l erythritol, 17.5 g / l glycerin,
Acetoin 67.7 mg / l, cell volume 10.8 v / v
%Met. Purification was performed using 1/2 of the solution obtained in the main culture and 12.1 l.

12.1 l of the culture solution was supplied to a continuous centrifuge with a separating plate, and separated into wet cells and a supernatant. The wet cells were added with 2.05 l of water (same volume as the separated wet cells) for washing, stirred, and then separated again by a separation plate type continuous centrifuge into the wet cells and the supernatant. The washing operation of the wet cells was repeated once again under the same conditions. All of the supernatant obtained by washing was added to the supernatant obtained by centrifugation of the culture solution. The total volume of the supernatant was 14.2 l.

For desalting 14.2 l of the supernatant,
As an ion exchange device, a strongly acidic cation exchange resin Diaion (“Diaion” is a registered trademark) SKIB type H (manufactured by Mitsubishi Kasei Corporation) 1.5 l packed column (50 mmφ)
× 765 mm filling length), weak basic anion exchange resin DIAION WA30 OH type (manufactured by Mitsubishi Kasei Corporation) 1.5
l Packing column (50mmφ × 765mm packing length), mixed acid tower as strong acid anion exchange resin Diaion SKIB
A column (50 m) packed with a mixture of 0.5 l of type H (manufactured by Mitsubishi Kasei) and 1.0 l of strong basic cation exchange resin DIAION PA408 OH type (manufactured by Mitsubishi Kasei)
mφ × 765 mm filling length). The supernatant was supplied to these three series of ion exchange towers at SV2 (1 / H), and when the supernatant was exhausted, water was extruded at the same speed. When 2.7 liters of the supernatant was supplied, the outflow of dilute erythritol from the mixed-bed tower started. Therefore, sampling was started, and sampling was performed until erythritol was completely drained. (19.4 kg).

Next, 31 g of powdered activated carbon was added, and the mixture was stirred well and filtered. The activated carbon separated by filtration was suspended and washed with 93 g of water, and the filtrate was added to the activated carbon treatment liquid. The erythritol recovery rate up to this step was as high as 98.3% due to sufficient washing of the cells, water extrusion of the ion exchange tower, and washing with activated carbon. Since a large amount of water was used for washing and water extrusion in the purification step, the liquid volume increased to 19.4 kg, and the erythritol concentration decreased to 13.1% by weight. Next, when the activated carbon-treated solution was concentrated to 4.31 kg, erythritol was 59.5% by weight and acetoin was 16.5% by weight. The acetoin removal rate in the concentration step was 91%.

The concentrated solution is placed in a crystallizer at 70 ° C. to 20 ° C.
After cooling for 8 hours, the precipitated crystals were separated by filtration and the wet crystals were further washed with 1.01 kg of cold water at 5 ° C. (0.5 times the filtered wet crystals). When the wet crystals were dried under reduced pressure, 1.74 kg of crystals were obtained. The crystals did not have a pungent odor like a drug. The mixed liquid amount of the crystallization mother liquor and the crystal washing filtrate was 3.58 kg, and the erythritol concentration was 23.0% by weight and the acetoin concentration was 19.9% by weight.

Comparative Example 1 The remaining 1/2 volume of the main culture solution obtained in Example 1 and 12.1 l were purified. 12.1 l of the culture solution was supplied to a separation plate type continuous centrifuge, and separated into wet cells and a supernatant.
Avoid diluting the supernatant without washing the wet cells with water,
The wet cells were discarded as they were. The resulting supernatant was 10.1
l.

For desalting 10.1 l of the supernatant,
The same ion exchange device as in Example 1 was used. The supernatant was supplied at SV2 (1 / H) in the same manner as in Example 1. When the supernatant was exhausted, water was extruded at the same speed. To avoid diluting the processing solution by ion exchange treatment, start sampling after the concentration of the effluent from the mixed bed becomes half of the concentration of the supply solution, and push out the water after stopping the supply of the undiluted solution to remove the effluent. The sampling was stopped when the concentration of dropped to half that of the stock solution.

Next, 25 g of activated carbon was added to the desalted solution, and the mixture was thoroughly stirred and filtered. Since dilution with water was avoided in the purification step, the amount of the treatment liquid was 11.1 kg, and a high value of erythritol concentration of 18.3% by weight was obtained. However, the erythritol recovery up to this step was as low as 78.1%.

When the activated carbon treatment liquid was concentrated to 4.22 kg, the erythritol concentration was 48.0% by weight and the acetoin concentration was 33.4% by weight. The removal rate of acetoin in the concentration step was 78%.

The concentrated solution is placed in a crystallizer at 55 ° C. to 20 ° C.
The mixture was gradually cooled for 8 hours, and the precipitated crystals were separated by filtration. Further, the wet crystals were washed with 614 g of water (0.5 times the amount of the wet crystals) at 5 ° C. When the wet crystals were dried, 1.06 kg of crystals were obtained. The crystals had a weak chemical-like pungent odor.

Example 2 Purified glucose 300 g / l, yeast extract 2.5 g / l,
0.6 l each of a sterilized seed medium having a composition of malt extract 2.5 g / l and polypeptone 5 g / l was placed in four 3 l Erlenmeyer flasks, and Trichosporonoides megatiliensis SN was added.
-G42 strain (former name: Aureobasidium SN-G4)
(2 strains) and inoculated at 30 ° C. for 96 hours to give a preculture. In a sterilized 50 l jar, individually sterilized purified glucose (glucose purity 95% by weight) 1
2.12kg of liquid and corn steep liquor (CSL) 1.87 kg was dissolved was added, then after adjusting the pH addition of preculture 1.90l obtained by shaking culture in 4.2, were the main culture. The liquid volume at the start of the main culture was 30.7 l, and the composition was 375 g / l glucose and 61 g / l CSL. Stirring speed 300 rpm, air supply speed 0.25
Main culture was performed at vvm and a temperature of 35 ° C. for 142 hours. Amount of liquid at the end of culture is 23.2L, the composition Ellis lithol 1
98 g / l, glycerin 12 g / l, acetoin 102
mg / l and cell volume was 15.8 v / v%.

Purification was carried out using 11.6 l of a half of the liquid obtained in the main culture. 11.6 L of the culture solution was supplied to a separation plate type continuous centrifuge, and separated into wet cells and a supernatant. The wet cells were added with 2.96 l (equivalent volume to the separated wet cells) of water for washing, stirred and then separated again into wet cells and a supernatant by a continuous centrifuge with a separating plate. The washing operation of the wet cells was repeated once again under the same conditions. All of the supernatant obtained by washing was added to the supernatant obtained by centrifugation of the culture solution. The total volume of the supernatant was 14.6 l.

To remove the salts in the supernatant and the oligosaccharides in the purified glucose obtained by the chromatographic separation, the cell supernatant was concentrated to 6.74 kg, and the erythritol concentration was 33.3% by weight. The concentration is 5
It was 5.1 weight ppm. The removal rate of acetoin in the concentration step was 68%.

At 75 ° C., the erythritol concentrate was converted to a strongly acidic cation exchange resin Diaion UBK530 Na
SV0.5 in a 57.4 l packed chromato column (250 mmφ x 1,170 mm packed length) (Mitsubishi Kasei Co., Ltd.)
At 7 (1 / H), the solution was passed through the top of the tower, and when the concentrated solution was exhausted, water at 75 ° C. was continuously supplied. Up to 34.4 liters of the effluent from the bottom of the column are salts mainly contained in the concentrate and were discarded. Next, since the effluent contained erythritol, sampling was started, and a total of 16.1 was obtained.
At the 1st stage, erythritol was no longer observed in the effluent, so the sampling was stopped.

For desalting 16.1 l of the supernatant,
As an ion exchange device, a strongly acidic cation exchange resin Diaion SKIB H type (manufactured by Mitsubishi Kasei Corporation) 1.5 l packed column (50 mmφ × 765 mm packed length), a weakly basic anion exchange resin Diaion WA30 OH type ( 1.5 l packed column (manufactured by Mitsubishi Chemical Corporation) (50 mmφ × 76
5 mm packed length), strong acid cation exchange resin DIAION SK1B H type (Mitsubishi Kasei Co., Ltd.)
0.5 l and strongly basic anion exchange resin Diaion P
A column (50 mmφ × 765 mm packed length) packed with 1.0 l of A408 OH type (manufactured by Mitsubishi Kasei Corporation) was used. The supernatant was supplied by these three series of ion exchange towers SV2 (1 / H), and when the supernatant was exhausted, water was extruded at the same speed. When 2.7 liters of the supernatant was supplied, the outflow of dilute erythritol from the mixed-bed column started. Therefore, sampling was started, and the sample was collected until the erythritol had completely flowed out. (21.
1 kg).

Next, 25 g of activated carbon was added, and the mixture was stirred well and filtered off. The filtered activated carbon was washed with 75 g of water and the filtrate was added to the activated carbon treatment. The recovery rate of erythritol up to this step was as high as 96.6% due to sufficient washing with bacterial cells, water extrusion of the ion exchange tower, and washing with activated carbon. Since a large amount of water was used for washing and water extrusion in the purification process and diluted, the liquid volume increased to 21.1 kg and the erythritol concentration decreased to 10.5% by weight. Next, when the activated carbon-treated solution was concentrated to 4.05 kg, erythritol was 54.7% by weight and acetoin was 7.9% by weight. The total acetoin removal rate in the two concentration steps is 97
%Met.

The concentrated solution is placed in a crystallizer at 60 ° C. to 20 ° C.
The resultant was cooled slowly over 8 hours, and the precipitated crystals were separated by filtration. The wet crystals were further washed with 754 g of cold water at 5 ° C (0.5 times the amount of the wet crystals). When the wet crystals were dried under reduced pressure, 1.3
0 kg of crystals were obtained. The crystals did not have any chemical-like pungent odor. The mixture volume of the crystallization mother liquor and the crystal washing filtrate was 3.51 kg, and the erythritol concentration was 26.
The content was 3% by weight and the concentration of acetoin was 10.5% by weight.

Comparative Example 2 Purification was performed using 11.6 l of the remaining 1/2 volume of the main culture solution obtained in Example 2. 11.6 L of the culture solution was supplied to a separation plate-type continuous centrifuge, and separated into wet cells and a supernatant.
2.96 l of wet cells for washing (equivalent volume to isolated wet cells)
Was added, and the mixture was stirred and separated again into wet cells and a supernatant by a continuous centrifuge with a separating plate. The supernatant obtained by washing the wet cells was added to the supernatant obtained by centrifuging the culture. The total volume of the supernatant was 11.6 l.

For desalting 11.6 l of the supernatant,
The same ion exchange device as in Example 2 was used. The supernatant was supplied at SV2 (1 / H) as in Example 2, and when the supernatant was exhausted, water was extruded at the same speed. To avoid diluting the processing solution by ion exchange treatment, start sampling after the concentration of the effluent from the mixed bed becomes half of the concentration of the supply solution, and push out the water after stopping the supply of the undiluted solution to remove the effluent. The sampling was stopped when the concentration of dropped to half that of the stock solution. Then
Activated carbon (25 g) was added to the desalted liquid, stirred well, and filtered. Since dilution with water was avoided in the purification step, the amount of the treatment liquid was 12.6 kg, and a high value of erythritol concentration of 16.0% by weight was obtained. However, the recovery of erythritol up to this step was as low as 87.6%.

When the activated carbon-treated solution was concentrated to 3.99 kg, the erythritol concentration was 50.4% by weight and the acetoin concentration was 44.4% by weight. The acetoin removal rate in the concentration step was 83%. The concentrated solution was gradually cooled in a crystallizer from 58 ° C. to 20 ° C. for 8 hours, and the precipitated crystals were separated by filtration. Further, the wet crystals were washed with 657 g of water at 5 ° C. (0.5 times the amount of the wet crystals). When the wet crystals were dried, 1.13 kg of crystals were obtained. The crystals had a strong chemical-like pungent odor.

Example 3 A mixture of the crystallized mother liquor of Example 1 and a crystal washing solution 6.58 k
g was divided into two equal parts, and 1.79 kg thereof was desalted. 1.
In order to desalinate 79 kg of the mixed solution, a strongly acidic cation exchange resin Diaion SKIB was used as an ion exchange device.
H-type (manufactured by Mitsubishi Chemical Corporation) 0.2 l packed column (20
mmφ × 637 mm filling length), weakly basic anion exchange resin DIAION WA30 OH type (manufactured by Mitsubishi Kasei Corporation)
0.21 l packed column (20 mm φ x 637 mm packed length), 0.067 l of strongly acidic cation exchange resin Diaion SKIB type H (manufactured by Mitsubishi Kasei Co., Ltd.) and strongly basic anion exchange resin Diaion PA408 as mixed bed tower
A column (20 mmφ × 637 mm packed length) packed with 0.133 l of OH type (manufactured by Mitsubishi Kasei Corporation) was used. The mixed solution was added to these three series ion exchange towers.
The mixture was supplied at V2 (1 / H), and when the mixture was exhausted, water was extruded at the same speed. When 0.36 l of the mixed solution was supplied, the outflow of dilute erythritol from the mixed bed column started. Therefore, sampling was started, and the sample was collected until the erythritol was completely drained. The total sampled amount was 2.33 kg. there were. The erythritol concentration of the treatment liquid was 17.7% by weight.

When the ion-exchange resin-treated solution was concentrated to 1.01 kg, the erythritol concentration was 40.7% by weight and the acetoin concentration was 9.3% by weight. The acetoin removal rate in the concentration step was 74%. The concentrated solution was gradually cooled in a crystallizer from 57 ° C. to 20 ° C. for 8 hours to precipitate erythritol crystals. The precipitated crystals were separated by filtration, and then washed with 133 g of water (0.5 times the amount of wet crystals) at 5 ° C. When the wet crystals were dried, 229 g of dry crystals were obtained.

The remaining half of 1.79 kg of the mixture of the mother liquor and the crystal washing solution of Example 1 was concentrated as it was until erythritol was 40.7% by weight. The amount of the concentrated liquid is 1.01 kg, and the acetoin concentration is 13.3 ppm by weight.
Met. The acetoin removal rate in the concentration step was 62%.

Next, the concentrated solution was cooled to 57 ° C.
The mixture was gradually cooled to 8 ° C. for 8 hours to precipitate erythritol crystals. The precipitated crystals were separated by filtration and washed with 134 g of water (0.5 times the amount of wet crystals) at 5 ° C. When wet crystals are dried, 2
29 g of dry crystals were obtained. When the dried crystals obtained by the two purification methods were compared, none of the crystals had a pungent odor like a drug. The crystals obtained by treating the crystallized mother liquor with an ion-exchange resin were erythritol crystals having a pleasant sweet flavor closer to that of sucrose and a remarkably cool sweetness.

Example 4 The amount of the mixture of the crystallization mother liquor and the crystal washing filtrate in Example 2 was 3.
51 kg, erythritol concentration 26.3% by weight, acetoin concentration 10.5% by weight
The solution was passed at V2 (1 / H), and water was subsequently extruded.
From the point in time when 0.36 l of the mixed solution was supplied, the outflow of dilute erythritol from the mixed bed column started, so the sampling was started,
When the liquid was collected until erythritol was completely discharged, the total amount of the collected liquid was 4.05 kg. The erythritol concentration of the treatment liquid was 22.7% by weight.

When the ion exchange resin-treated solution was concentrated to 2.02 kg, the erythritol concentration was 45.6% by weight and the acetoin concentration was 5.7% by weight. The acetoin removal rate in the concentration step was 69%. The concentrated solution was gradually cooled in a crystallizer from 53 ° C. to 20 ° C. in 8 hours to precipitate erythritol crystals. The precipitated crystals were separated by filtration, and then washed with 274 g of water (0.5 times the amount of wet crystals) at 5 ° C. When the wet crystals were dried, 471 g of dry crystals were obtained. No irritating odor like a drug was observed in the obtained dried crystals, and erythritol crystals having a pleasant sweet flavor closer to that of sucrose and a preferable refreshing sweetness were obtained.

Example 5 A sterilized seed medium having a composition of crystal glucose 300 g / l, yeast extract 20 g / l and thiamine hydrochloride 1.5 g / l.
Each 6 l was placed in three 3 l Erlenmeyer flasks, inoculated with Candida lipolytica, and shake-cultured at 30 ° C. for 94 hours to obtain a preculture liquid. In a sterilized 30l jar,
A solution of 6.09 kg of individually sterilized crystalline glucose, 0.34 kg of yeast extract, and 25.5 g of thiamine hydrochloride
Was added, and then 1.70 l of a pre-culture solution obtained by shaking culture was added to adjust the pH to 4.6, followed by main culture. The liquid volume at the start of the main culture was 17.0 l, and the composition was 358 g / l glucose, 20 g / l yeast extract, and 1.5 g / l thiamine hydrochloride. 500 rpm stirring speed
m, air supply rate 1.00 vvm, temperature 27 ° C 120
Main culture was performed for hours. The volume at the end of the culture is 14.8 l
The composition is 215 g / l erythritol and the remaining glucose 1
6 g / l, acetoin 29.0 mg / l, cell volume 1
2.0 v / v%.

14.8 l of the culture solution was supplied to a continuous centrifuge with a separating plate, and separated into wet cells and a supernatant. 2.78 l of water was added to the wet cells for washing, and after stirring, the wet cells were again separated into a wet cell and a supernatant by a separation plate-type continuous centrifuge. The washing operation of the wet cells was repeated once again under the same conditions.
All of the supernatant obtained by washing was added to the supernatant obtained by centrifugation of the culture solution. The total volume of the supernatant was 17.5 l.

When removing the salts in the supernatant liquid by chromatographic separation, the cell supernatant was concentrated to 8.19 kg, and the erythritol concentration was 33.3% by weight and the acetoin concentration was 17.4% by weight. there were. The acetoin removal rate in the concentration step was 61%.

At 75 ° C., the concentrated erythritol solution was added to a strongly acidic cation exchange resin Diaion UBK550 Na
SV0.5 in a 70.9 l packed chromato column (250 mmφ × 1,445 mm packed length) (Mitsubishi Kasei Co., Ltd.)
At 7 (1 / H), the solution was passed through the top of the tower, and when the concentrated solution was exhausted, water at 75 ° C. was continuously supplied. Up to 42.5 liters of the effluent from the lower part of the column were salts mainly contained in the concentrated liquid, and were discarded. Then, since the effluent contained erythritol, the collection was started and the total amount was 19.9.
At the stage of sampling 1, erythritol was no longer observed in the effluent, so sampling was stopped.

For desalting 19.9 l of the chromatized solution, a strongly acidic cation exchange resin Diaion SK1B type H (manufactured by Mitsubishi Kasei Co., Ltd.) was used as an ion exchange device.
1.5l packed column (50mmφ × 765mm packed length), weakly basic anion exchange resin Diaion WA30
OH type (Mitsubishi Kasei Corp.) 1.5 l packed column (5
0 mmφ × 765 mm filling length) 0.5 l of strongly acidic cation exchange resin Diacon SK1B H type (manufactured by Mitsubishi Kasei Corporation) and strongly basic anion exchange resin Diaion PA408 OH type (Mitsubishi Kasei Corporation) 1.)
0l mixed and packed column (50mmφ × 765mm
Filling length). The supernatant was supplied to these three series of ion exchange towers at SV2 (1 / H), and when the supernatant was exhausted, water was extruded at the same speed. From the time when 2.7 l of the supernatant was supplied, the outflow of dilute erythritol from the mixed-bed column started. Therefore, the collection was started and the sample was collected until the erythritol was completely drained.
It was 3.9 l (24.9 kg).

Next, 28 g of activated carbon was added, and the mixture was stirred well and filtered. The filtered activated carbon was washed with 85 g of water, and the filtrate was added to the activated carbon treated liquid. The erythritol recovery rate up to this step was as high as 97.2% due to sufficient washing with bacterial cells, water extrusion of the ion exchange tower, and washing with activated carbon water.

Since a large amount of water was used for washing and water extrusion during the purification step and dilution, the liquid volume was increased to 25.0 kg and the erythritol concentration was reduced to 10.8% by weight. Next, when the activated carbon treatment liquid was concentrated to 5.37 kg,
Erythritol 50.2% by weight, acetoin 3.0
It was ppm by weight. The total acetoin removal rate in the two concentration steps was 96%.

The concentrated solution is placed in a crystallizer at 60 ° C. to 20 ° C.
The mixture was gradually cooled over 8 hours, and the precipitated crystals were separated by filtration. The wet crystals were further washed with 770 g of cold water at 5 ° C. When the wet crystals were dried under reduced pressure, 1.32 kg of crystals were obtained.
The crystals did not have any chemical-like pungent odor.
The mixed liquid amount of the crystallization mother liquor and the crystal washing filtrate is 4.82 kg.
The erythritol concentration was 28.3% by weight and the acetoin concentration was 3.4% by weight.

[0054]

Industrial Applicability According to the present invention, erythritol crystals having a pleasant sweet taste similar to that of sucrose, having no pungent odor like a medicine, and having an extremely favorable cool sweetness can be industrially stably produced. .

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-215293 (JP, A) JP-A-1-320987 (JP, A) JP-A-1-199583 (JP, A) JP-A-5-1995 32570 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C12P 7/18 C07C 29/78 C07C 31/10

Claims (2)

(57) [Claims] 1. A method for producing erythritol crystals from an erythritol-containing liquid obtained from a fermentation method, wherein an acetoin concentration for crystallizing erythritol crystals from an erythritol-containing slurry liquid containing erythritol crystals is 1 to 20 ppm by weight. A method for producing an erythritol crystal. 2. An erythritol-containing slurry containing erythritol crystals, wherein the erythritol concentration is 40 to 6
2. The method according to claim 1, wherein erythritol crystals are crystallized at 5% by weight.