D-PSICOSE CRYSTAL AND PREPARATION METHOD THEREFOR

Abstract

The present disclosure relates to a preparation method for a D-psicose crystal containing 98% (w/w) or more D-psicose and 0.05% (w/w) or less ethanol based on 100% (w/w) of the entire crystal. The preparation method includes a first step of mixing a D-psicose-containing solution and an organic solvent, and a second step of adding a seed to the mixed solution according to the first step and then cooling the same to obtain a massecuite containing the D-psicose crystal. Therefore, it is possible to increase the yield of the D-psicose crystal from the D-psicose crystal solution and prepare a D-psicose crystal of sufficient size and appropriate shape for use in mass production with no bad taste/smell.

Claims

1. A D-psicose crystal comprising: 98% (w/w) or more D-psicose and 0.001% (w/w) to 0.05% (w/w) ethanol based on 100% (w/w) of the entire crystal.

2. The D-psicose crystal of claim 1, wherein a mean particle size (MA) is 200 μm or more.

3. A preparation method for a D-psicose crystal comprising: a first step of mixing a D-psicose-containing solution and an organic solvent; and a second step of adding a seed to the mixed solution according to the first step and then cooling the same to obtain a massecuite containing the D-psicose crystal.

4. The preparation method of claim 3, wherein the mixing in the first step is performed at 40° C. to 60° C., and a final temperature cooled according to the second step is 10° C. to 20° C.

5. The preparation method of claim 3, wherein in the second step, the seed is grown in a metastable zone by adjusting a cooling rate.

6. The preparation method of claim 5, wherein in the second step, the cooling rate is 0.05° C./hour to 1.4° C./hour.

7. The preparation method of claim 3, wherein in the second step, the cooling and the crystallization are performed for 20 hours to 70 hours.

8. The preparation method of claim 3, wherein the D-psicose-containing solution contains 95% (w/w) or more D-psicose.

9. The preparation method of claim 3, wherein a weight percentage of a finally obtained D-psicose crystal compared to the D-psicose content existing in the D-psicose-containing solution in the first step is 65% (w/w) or more.

10. The preparation method of claim 3, wherein the organic solvent is an alcohol.

11. The preparation method of claim 3, wherein the organic solvent includes at least one selected from ethanol, methanol, and propyl alcohol.

12. The preparation method of claim 3, wherein the organic solvent is a mixture with a water:organic solvent ratio of 1:0.5 or more in the D-psicose-containing solution.

13. The preparation method of claim 3, wherein in the D-psicose-containing solution, a concentration of the D-psicose is 80 brix to 85 brix.

14. The preparation method of claim 3, further comprising: a third step of separating and drying the D-psicose crystal from the massecuite.

15. The preparation method of claim 14, further comprising: a fourth step of recovering the organic solvent from a crystal mother liquor in which the D-psicose crystal is separated according to the third step, and then reusing the recovered organic solvent as the organic solvent of the first step.

16. The preparation method of claim 14, further comprising: a fifth step of removing the organic solvent from a crystal mother liquor in which the D-psicose crystal is separated according to the third step, and then reusing the crystal mother liquor in preparing a D-psicose-containing solution.

17. The preparation method of claim 14, wherein a concentration of the organic solvent in the D-psicose crystal is adjusted to 0.05% (w/w) or less by the drying.

Description

DESCRIPTION OF DRAWINGS

[0061] FIG. 1 is a micrograph of a D-psicose crystal prepared in Example 1.

[0062] FIG. 2 is a particle size analysis result of the D-psicose crystal prepared in Example 1.

[0063] FIG. 3 is a particle size analysis result of a D-psicose crystal composition prepared in Example 2.

[0064] FIG. 4 is a diagram illustrating a shape of a D-psicose crystal cake prepared in Example 6.

[0065] FIG. 5A is a scanning electron micrograph (SEM) of a surface of the D-psicose crystal prepared in Example 1. FIG. 5B is a scanning electron micrograph (SEM) of a surface of a D-psicose crystal prepared in the Comparative Example.

[0066] FIG. 6 is a diagram illustrating a method for measuring a repose angle.

MODE FOR INVENTION

[0067] Hereinafter, the present disclosure will be described in more detail with reference to the following Examples. However, the following Examples are merely illustrative of the present disclosure, and the scope of the present disclosure is not limited thereto.

Example 1: Preparation of High-Purity D-Psicose Crystal Composition with Purity of 98% (w/w) or Higher and Containing 0.05% (w/w) of Less Ethanol

[0068] (1) Production of Low-Purity D-Psicose Solution Using Microorganism

[0069] A 50 brix (%) fructose solution (enzyme reaction substrate solution) with a purity of 95% (w/w) or higher was prepared. As in the epimerization enzyme reaction disclosed in Korea Patent Publication No. KR 10-2011-0035805 A (Korea Patent Application No. 10-2009-0118465), where a D-psicose epimerase separated from a strain of Corynebacterium glutamicum KCCM 11046P was immobilized to a sodium alginate carrier and filled into isomerization equipment (isomerization tower, HANJOO Machine Industrial Co., Ltd.), and then the prepared enzyme reaction substrate solution passed through a heat exchanger at a space velocity (SV) [flow rate (L)/time (Hr)/resin amount (L)] by raising to a temperature of 50° C. at a rate of 5° C. to 20° C. per hour to obtain an epimerized D-psicose solution. At this time, the purity of the D-psicose was about 24% (w/w).

[0070] (2) Purification of D-Psicose Solution

[0071] The epimerized D-psicose solution was first cooled to a temperature of 30° C. to 40° C. at a rate of 5° C. to 10° C. per hour by the heat exchanger, and was then passed through a column in which a decolorant was filled to be decolored, and subsequently passed through a column in which a strongly acidic cation-exchange resin substituted with a hydrogen group and a weakly acidic anion-exchange resin substituted with a hydroxyl group were filled at SV 3 to be desalinized. The final ionic composition was adjusted to be 10 microsiemens or less per unit cm through the measurement of an electric conduction system, and the purity of the D-psicose in the desalinized enzyme reaction solution was maintained at 24% (w/w).

[0072] (3) Separation of High-Purity D-Psicose Solution Using Chromatography

[0073] The ion-purified D-psicose-containing solution was added to a low-temperature evaporator (forced thin-film evaporator, WELCRON Hantec), concentrated to a concentration of 60 brix (%) for a short time of 10 minutes to 15 minutes at a temperature of 55° C. to 70° C., and again cooled at a rate of 5° C. to 25° C. per hour through the heat exchanger to be separated into a purified D-psicose solution having a purity of D-psicose of 95% (w/w) or higher and a fructose-containing solution having a purity of fructose of 70% (w/w) or higher by continuous chromatography in a column in which a strongly acidic cation-exchange resin with a calcium active group attached was filled at 50° C. to 60° C.

[0074] The fructose-containing solution having a purity of 70% (w/w) or higher separated by the continuous chromatography was recovered and cooled at a rate of 20° C. to 30° C. per hour to be re-circulated in an epimerization process of fructose at 30° C.

[0075] (4) Crystallisation by Concentration, Organic Solvent Treatment, and Cooling of D-Psicose Solution

[0076] The purified D-psicose solution having a purity of 95% (w/w) or higher separated by the continuous chromatography was concentrated at a temperature of 55° C. to 70° C. to be adjusted to a concentration of 85.0 brix (%). The concentrated D-psicose solution having a purity of 95% (w/w) or higher was rapidly cooled to a temperature of 40° C. at a rate of 5° C. to 20° C. per hour through the heat exchanger, and then mixed with ethanol corresponding to a weight ratio of water:ethanol=1:1.13 as compared to water content excluding solids.

[0077] An appropriate amount of a seed was added to the D-psicose solution mixed with the ethanol cooled to 40° C., and this was then cooled to a final temperature of 10° C. at a cooling rate of 1° C. per hour and crystallized for 30 hours to obtain a massecuite containing the D-psicose crystal.

[0078] The massecuite containing the D-psicose crystal was added to a high-speed centrifugal dehydrator and spun at 4,000 rpm for 10 minutes, and then a supernatant was discharged to obtain a D-psicose crystal containing an excess amount of ethanol. At this time, the residual supernatant was washed by spraying deionized water or ethanol, and the concentration of ethanol contained in the obtained D-psicose crystal was about 0.15% (w/w).

[0079] The recovered D-psicose crystal containing an excess amount of ethanol was moved to a fluidized bed dryer or a vacuum dryer and dried for 1 hour to 2 hours to remove an excess amount of ethanol and obtain a D-psicose crystal having a purity of 98% (w/w) or higher and containing 0.03% (w/w) ethanol. An amount of the D-psicose crystal obtained after king was 2,252 g, which was recovered at a rate of about 81% as compared to 2,780 g existing in the D-psicose solution separated and concentrated by the continuous chromatography, and the crystal size was MA 336 (FIGS. 1 and 2).

[0080] Additionally, the mother liquor separated in the crystallization, that is, a supernatant dehydrated from the massecuite, may be reused in the step of recovering the ethanol by distillation and mixing the recovered ethanol with the D-psicose solution. The solution containing D-psicose in which the ethanol is removed after the distillation is cooled to 30° C. and may be re-circulated in a column in which the strongly acidic cation-exchange resin substituted with a hydrogen group and the weakly acidic anion-exchange resin substituted with a hydroxyl group are filled, or re-circulated by continuous chromatography.

Example 2: Preparation of High-Purity D-Psicose Crystal Composition with Purity of 98% (w/w) or Higher and Containing 0.05% (w/w) of Less Ethanol

[0081] In Example 1 above, except that a D-psicose-containing solution concentrated to 80.0 brix (%) was cooled to 50° C., ethanol corresponding to a weight ratio of water:ethanol=1:9 as compared to water content excluding solids was mixed, a cooling rate was 0.5° C. per hour, and a final temperature was up to 20° C. for 60 hours, a high-purity D-psicose crystal composition having a purity of 98% (w/w) or higher and 0.05% (w/w) or less ethanol was prepared in the same manner as in Example 1.

[0082] An amount of the obtained D-psicose crystal having a purity of 98% (w/w) or higher and containing 0.05% (w/w) or less ethanol was 2,307 g, which was recovered at a rate of about 83% as compared to 2,780 g of initially dissolved D-psicose, and the crystal size was MA 241 (FIG. 3).

Example 3: Preparation of D-Psicose Crystal Composition Having Purity of 98% (w/w) or Higher and Containing 0.05% (w/w) Ethanol

[0083] In Example 1 above, except that a drying time was 30 minutes to 1 hour, a high-purity D-psicose crystal composition having a purity of 98% (w/w) or higher was prepared in the same manner as in Example 1.

[0084] The obtained D-psicose crystal contained 0.05% (w/w) ethanol, and the purity was 98% (w/w) or higher.

Example 4: Preparation of D-Psicose Crystal Composition Having Purity of 98% (w/w) or Higher and Containing 0.06% (w/w) Ethanol

[0085] In Example 1 above, except that a drying time was 10 minutes to 20 minutes, a high-purity D-psicose crystal composition having a purity of 98% (w/w) or higher was prepared in the same manner as in Example 1.

[0086] The obtained D-psicose crystal contained 0.06% (w/w) ethanol, and the purity was 98% (w/w) or higher.

Example 5: Preparation of High-Purity D-Psicose Crystal by Changing Type of Mixed Organic Solvent

[0087] In Example 1 above, except that methanol and isopropyl alcohol were mixed in the concentrated D-psicose-containing solution, a high-purity D-psicose crystal having a purity of 98% (w/w) or higher was prepared in the same manner as in Example 1.

[0088] When methanol was used, the yield of the obtained D-psicose crystal was 33%, and a mean particle size was MA 109.

[0089] When isopropyl alcohol was used, the yield of the obtained D-psicose crystal was 32%, and a mean particle size was MA 61.

Example 6: Preparation of High-Purity D-Psicose Crystal Composition Using Organic Solvent without Controlling Cooling Rate

[0090] In Example 2 above, except that ethanol corresponding to a weight ratio of water:ethanol=1:4 as compared to water content excluding solids was mixed in the concentrated D-psicose-containing solution, and a seed was added and then crystallized for 30 hours of cooling at a final temperature of 20° C. within 30 minutes to 1 hour without controlling the cooling rate, a high-purity D-psicose crystal composition having a purity of 98% (w/w) or higher and containing 0.05% (w/w) or less ethanol was prepared in the same manner as in Example 2.

[0091] An amount of the obtained D-psicose crystal was 1,056 g, which was recovered at a rate of about 38% as compared to initially dissolved D-psicose, and a generated D-psicose crystal block was 1,084 g and confirmed as having been recovered at a rate of 39%.

Comparative Example: Preparation of High-Purity D-Psicose Crystal by Cooling Crystallization Method without Using Organic Solvent

[0092] In Example 2 above, except that the concentrated D-psicose-containing solution was cooled to an initial temperature of 40° C. and then cooled to 20° C. for 80 hours without mixing ethanol, a high-purity D-psicose crystal having a purity of 98% (w/w) or higher was prepared in the same manner as in Example 2.

[0093] The yield of the obtained D-psicose crystal was 53%, and a mean particle size was MA 374.

Test Example 1: Confirmation of Effect of Removing Residual Ethanol

[0094] The high-purity D-psicose crystals in Example 1 (containing 0.03% (w/w) or less residual ethanol), the Comparative Example, Example 4, and Example 3 were consumed by a subject in a predetermined amount in powder form, and then a 3-point test was performed to evaluate whether a difference was distinguished. Two test groups were arranged with three options, and a tester consumed the three options in sequence without knowing the arrangement order to select which had a different taste. The test was performed by 20 testers three times, and whether there was a difference was evaluated according to the correct-answer rate over the total number of tests. A D-psicose crystal and a residual ethanol concentration % (w/w) used in the evaluation were shown in Table 1, and an evaluation result was shown in Table 2. The evaluation was performed by counting the number of correct answers, comparing the total answer number and the correct answer number with a significance test table, and determining whether there was a statistical significance. When the test was performed 60 times, if the correct answer number was 27 or more, it was determined that there was a significant quality difference.

TABLE-US-00001 TABLE 1 Comparative Example 3 Example 1 Example 4 Example Residual ethanol 0.05 0.03 0.06 0 concentration (%, w/w)

TABLE-US-00002 TABLE 2 Test Correct- results Number of Number of answer Presence/ testing correct rate absence of Comparative group times answers % difference Comparative Example 4 60 48 80.0 Presence Example Comparative Example 3 60 22 36.7 Absence Example Comparative Example 1 60 12 20.0 Absence Example Example 4 Example 3 60 43 71.7 Presence Example 4 Example 1 60 46 76.7 Presence Example 3 Example 1 60 11 18.3 Absence

[0095] It was confirmed that there was no functional difference in the D-psicose crystals (Examples 1 and 3) containing 0.05% (w/w) or less residual ethanol as compared to a D-psicose crystal (Comparative Example) prepared by a method without using an organic solvent. From this, it can be seen that when the residual ethanol is adjusted below a predetermined concentration, a taste equivalent to that of the original D-psicose crystal is achieved.

Test Example 2: Confirmation of Effect of Reducing Bad Taste/Smell Intensity by Removal of Residual Ethanol

[0096] In Test Example 1 above, the bad taste/smell intensity for the same test group (Table 1) used in the test was evaluated. 20 testers consumed the D-psicose crystal, and then the bad taste/smell intensity was expressed as a level (5 points indicated a case where the bad taste/smell intensity was maximal), and the evaluation results were shown in Table 3. It was confirmed that there was no difference in bad taste/smell in the D-psicose crystals (Examples 1 and 3) containing 0.05% (w/w) or less residual ethanol as compared to a D-psicose crystal (Comparative Example) prepared by a method without using an organic solvent From this, it can be seen that when the residual ethanol is removed to be below a predetermined concentration, the bad taste/smell is equivalent to that of the original D-psicose crystal.

TABLE-US-00003 TABLE 3 Comparative Example Example 4 Example 3 Example 1 1.9 ± 0.8 3.0 ± 0.4 2.0 ± 0.9 1.9 ± 0.7

Test Example 3: Confirmation of Smooth Surface Effect by Containing Ethanol

[0097] The surfaces of high-purity D-psicose crystals in Example 1 (containing 0.03% (w/w) or less residual ethanol) and the Comparative Example were examined with SEM. The results were shown in FIG. 5.

[0098] It was confirmed that as compared to the D-psicose crystal (FIG. 5B) without addition of ethanol in the Comparative Example, the surface of the D-psicose crystal (FIG. 5A) with addition of ethanol in Example 1 was smooth. From this, it can be seen that the smoothness of the surface of the D-psicose crystal is increased by adding ethanol, and thus the surface thereof is lustrous or glossy.

Test Example 4: Confirmation of Effect of Increasing Crystal Fluidity by Containing Ethanol

Test Example 4.1: Measurement of Fluidity

[0099] The fluidity of the D-psicose crystal (Example 1) containing 0.03% (w/w) or less residual ethanol was compared with that of the D-psicose crystal (Comparative Example) prepared by a method without using an organic solvent and evaluated. For evaluation of the fluidity, a fluidity meter was used.

TABLE-US-00004 TABLE 4 Inlet diameter 1.5 cm Tray diameter 5.0 cm Inlet-tray spacing 15 cm Added amount 30 g

[0100] Table 4 above is a table showing measurement conditions of the fluidity meter.

Fluidity=[(weight of added powder−weight of tray residual powder)/weight of added powder×100)]

[0101] As a resultant value calculated according to the formula increases, the fluidity of the crystal increases.

Test Example 4.2: Measurement of Repose Angle

[0102] Additionally, an effect of increasing fluidity by containing ethanol was confirmed by measuring a repose angle. The repose angle refers to a maximum inclined angle which may be deposited without flowing down when deposits that have not yet set are deposited on a slope, and when the repose angle is smaller, the fluidity of the crystal is larger (FIG. 6).

[0103] The repose angle was obtained by measuring an angle of the top surface of a composition with a graduator after a D-psicose crystal composition passed through a funnel installed on a horizontal surface at a predetermined speed.

TABLE-US-00005 TABLE 5 Fluidity Repose angle Example 1 59.7 35 Comparative Example 48 45

[0104] Table 5 above is a table showing measurement results of the fluidity and the repose angle. From Table 5, it was confirmed that in the case of D-psicose with ethanol added, the fluidity was increased, and as a result, it is suggested that since D-psicose containing ethanol has low viscosity, crystallization proceeds while the seed is dispersed, and thus it may afford a high yield and degree of crystallization.

[0105] It will be appreciated by those skilled in the art that the present disclosure as described above may be implemented into other specific forms without departing from the technical spirit or essential characteristics thereof. Thus, it is to be appreciated that embodiments described above are intended to be illustrative in every sense, and not restrictive. The scope of the present disclosure is represented by the claims described below rather than the detailed description, and it is to be interpreted that the meaning and scope of the claims and all changes or modified forms derived from the equivalents thereof come within the scope of the present disclosure.