JP2003319800A - Method for producing sugar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing sugar, by which the physical properties, such as melting point, of the sugar can be controlled in response to uses. <P>SOLUTION: This method for producing the sugar, having a crystallization process for growing sucrose crystals from the supersaturated solution of the sucrose, is characterized in that the sucrose crystals comprise three or more crystal forms having different melting points and that the crystal forms and the melting points of the sugar are controlled by adjusting the crystallization conditions of the crystallization process. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing sugar.

[0002]

BACKGROUND OF THE INVENTION Commercially available sugar has a high degree of purification, and the purity of granulated sugar is 99.9% or more, and it can be said that it is one of the highest-purity chemical products. However, some manufacturers of products made from sugar (such as confectionery)
In some cases, sugar makers are specified and used, and it can be seen that there is a difference in quality even for high-purity sugar.

[0003] The melting point of the cane sugar crystal products (glacial sugar, granuose, josou, chuso, sucrose, cultivated white sugar) is 166 to 191.
C. and beet sugar range from 180 to 189.degree. C., and the melting point of sucrose in cultivated sucrose (189 to 191.degree. C.) is the highest (Minori Kamota: Journal of the Institute of Advanced Sugar Science, p.158-238). Moreover, the melting points (average of three measurements) of Josou and Granu-sugar were 177.
There are differences in melting points between highly refined sugar products, 5 ° C and 181.6 ° C. From these, it is understood that the quality of highly purified sugar is influenced not only by the amount of impurities contained in a trace amount but also by the difference in melting point.

There are various descriptions on the melting point of sucrose crystals, and the ones investigated by the present inventors are listed below. A low melting point of 160 ° C. is described in the physics and chemistry dictionary (Saburo Nagakura et al .: Encyclopedia of physics and chemistry, 5th edition, p696, Iwanami Shoten (1998)), S.H. V. SHAH et al. Observed a value of 188 ℃ for recrystallized products from alcohol (SVSH
AH and YM CHAKRADEO: Curret Science, 1936 (3), 652
~ 653 (1936)). The Sugar Handbook describes that the melting point fluctuates because trace amounts of impurities and pyrolysates affect it, and that the correct melting point is 189 to 191 ° C. (Eijiro Hamaguchi, Yoshito Sakurai: Sugar Handbook, p.409 (Asakura Shoten), Principles of Sugar Tch
nology has a similar description (P.HONIG: Principles of
Sugar Tchnology, p.20 (Elsevier, Amsterdam) (195
3)). Thus, the melting point described in the literature is 160 to 191.
It covers a wide range of ℃.

There is a view that the melting point of sucrose crystals is influenced by a trace amount of impurities contained in the crystals and a thermal decomposition product generated when the melting point is measured. On the other hand, sucrose crystals have various forms of "crystals". Body ”(different modification
It is also suggested that s) exists.

[0006]

By the way, sugar is used in many applications including confectionery and cooking, and there is an optimum melting point depending on the application. For example, in the candy work, it is preferable that the melting point of sugar used in the candy is low in order to facilitate the work.

However, there has been no sugar having optimized physical properties such as melting point depending on the application.

The present invention has been proposed in view of such conventional circumstances, and an object of the present invention is to provide a method for producing sugar whose physical properties such as a melting point can be adjusted depending on the use.

[0009]

The method for producing sugar of the present invention is a method for producing sucrose having a crystallization step of growing sucrose crystals from a supersaturated solution of a sucrose body, wherein the sucrose crystals have different melting points. It is characterized by comprising three or more kinds of crystal forms, and controlling the crystal form by adjusting the crystallization conditions in the crystallization step, and controlling the melting point of sucrose obtained.

In the sugar production method of the present invention as described above, the crystal form is controlled by changing the crystallization conditions in the crystallization step, so that a sugar whose melting point is adjusted according to the application is obtained. You can

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing sugar to which the present invention is applied will be described in detail with reference to the drawings.

[0012] Sugar is generally obtained through the following steps. First, raw materials such as sugar cane and beet are squeezed to obtain sugar juice, impurities are removed and crystallized to produce raw sugar.
Next, molasses is mixed with the obtained raw sugar and heated to dissolve the impurities adhering to the crystal surface. Then, it is separated by a centrifuge into crystals and impurities attached to the surface. Then, the raw material sugar whose surface has been washed is dissolved in warm water, lime is further added to blow carbon dioxide gas to precipitate impurities, and the impurities are removed by filtration (carbonic acid saturating method). Furthermore, impurities are carefully removed with activated carbon, bone charcoal, ion exchange resin, etc. As a result, the sugar solution becomes colorless and transparent. The sugar solution is boiled down to generate crystals (recrystallization), and the crystals are separated by a centrifuge to obtain sugar with high sucrose purity.

Here, in the present invention, the crystal form of the obtained sucrose crystal is controlled by appropriately changing the crystallization conditions of sucrose, and thereby the physical properties such as the melting point of sugar are adjusted to desired values. .

The present inventors have found that the difference in melting point is mainly due to the difference in crystal structure because there is a large difference in measured melting point even though the amount of impurities contained in the sucrose crystal is extremely small. I thought Therefore, the melting point of crystals prepared under different conditions and the results of differential scanning calorimetry were analyzed, and the sucrose crystal structure was considered.

First, the present inventors obtained sucrose crystals by different preparation methods and investigated the difference in their physical properties. Here, commercially available high-purity granulated sugar was used for the preparation of sucrose crystals. The water content of this granulated sugar is 0.0
08%, reducing sugar 0.005%, color value 6.5 IU, electrical conductivity ash 0.0003%.

<Preparation of sucrose crystals by decoction method> Sample granulated sugar was dissolved in purified water to prepare a supersaturated sugar solution. Generate crystal nuclei from this supersaturated sugar solution by impact,
Decoction was performed at 52 ° C. for 1 hour using an automatic crystal can to grow crystals. Then, sucrose crystals were obtained by centrifugal filtration. The crystals thus obtained are referred to as "decoction crystals"
Called.

<Preparation of sucrose crystals from ethanol> Sample granulated sugar was dissolved in 96% ethanol to prepare a supersaturated sugar solution. This 96% ethanol was obtained by diluting 99% synthetic undenatured ethanol manufactured by Shinwa Alcohol Sangyo with water, and the supersaturated sugar solution was dissolved by heating and then cooled to room temperature. Crystal nuclei were generated from this supersaturated sugar solution by ultrasonic stimulation, and then the crystals were grown in a eggplant-shaped flask while rotating and stirring at about 30 ° C. with occasional concentration, and the produced crystals were collected by centrifugal filtration. The crystals thus obtained are called "ethanol-method crystals".

The melting point and differential scanning calorimetry of the sucrose crystals thus prepared were measured.

The melting point was measured by using an air bath method minute melting point measuring device (manufactured by Mitamura Riken Kogyo Co., Ltd.), and the temperature rising rate was set to about 1 ° C./minute near the melting point.

In the differential scanning calorimetry, the prepared sucrose crystals were crushed in a mortar, and about 6 mg was analyzed at 10 ° C. using a differential scanning calorimeter Pyris1 (PerkinElmer, Ct., USA).
The analysis was performed at a heating rate of 1 / min.

The melting point measurement results were 176 ° C. for the infusion method crystal and 184 ° C. for the ethanol method crystal. Both crystals were prepared from the same high-purity granulated sugar, but the melting points of the produced crystals were different if the preparation methods were different,
The melting point of the ethanol method crystals was as high as 8 ° C. However, the impurities contained in the crystals from these same raw materials are extremely small, and there is almost no difference in the content.
Further, since the melting points were measured under the same conditions, it is considered that the difference in the melting points is not caused by the impurities stored in the crystals or the thermal decomposition products during the melting point measurement but caused by the difference in the crystal structure.

Further, the changes of the ethanol method crystals and the sucrose method crystals upon heating and melting were examined by differential scanning calorimetry (DSC). The relationship between heating temperature and heat absorption is shown in FIG. The curve of the infusion method crystal has three endothermic peaks, and the curve of the ethanol method crystal shows only one gentle peak, and the shapes of the two curves are obviously different. When the crystal absorbs the applied heat and part of its structure collapses or melts,
Since the endothermic peak occurs, it is considered that the difference between the two curves is due to the difference in crystal structure.

Next, the factors for producing sucrose crystals having different structures will be described. In general, a crystal is formed by arranging molecules in a regular and orderly manner, and some kind of binding action (affinity) works between the molecules. The bonding action includes ionic bond, hydrogen bond, hydrophobic bond, etc.,
In the case of sucrose crystals, hydrogen bonds are considered to be the main. When sucrose molecules are aligned for crystal formation, there are several hydrogen bonding sites between molecules, and the bonding force between molecules varies depending on the number of hydrogen bonding sites and the distance and direction between bonding atoms. In the case of a sucrose crystal, there are not only one kind of molecular arrangement (bonding method) but also several kinds of molecules, and the intermolecular bonding force varies depending on the bonding method. Here, for convenience,
The sequence of molecules with weak binding is called X-form (X modification), and the sequence of strong binding is called Z-form (Z modification).
An array of medium strength is called a Y-body (Y modificatton).

During crystallization, the sucrose molecules undergo several kinds of arrangement to form the X-form to the Z-form. And FIG.
The peak near 150 ° C of the curve of the infusion method crystal in
Body, gentle peak around 160 ℃ is Y body, 180 ℃
The peak in the vicinity is derived from the Z form. Since the sucrose molecule freely moves in a solution, any sequence of X-form to Z-form may occur, but it is difficult for the specific sequence to occur due to steric hindrance, or the specific sequence is inhibited by the crystallization conditions. In some cases, the structure of the resulting crystal is partially or wholly different. For example, if the formation of the X body and the Y body is inhibited, the formation rate of the Z body increases.

When the amount of X-form and Y-form is smaller than that of Z-form, the crystal maintains the crystal form (solid state) up to the collapse temperature of Z-form, and when the amount of Z-form is small, it reaches the collapse temperature of Z-form. By then the crystal form collapses (melts). That is, a crystal having a large amount of Z-body has a high melting point.

Thus, sucrose has a crystalline polymorphism. The crystal polymorph means solids having the same molecule but different molecular arrangements, lattice energy, surface free energy, heat of fusion, melting temperature, solubility in solvent, solubility,
Dissolution rate etc. are different. The reason for the large difference in melting points of sucrose crystals that has been reported so far is
This is because sucrose has a polymorphism and the structure of the produced crystal differs depending on the crystal preparation conditions.

Since different crystal forms have different physical properties such as melting point and solubility, if the crystal form of sucrose can be controlled, it is possible to obtain sugar having optimized physical properties such as melting point according to the application. And the use of sugar is expanded.

Next, factors affecting the molecular arrangement of sucrose crystals will be described. In order for the sucrose molecules in the solution to crystallize, that is, adhere to the crystal surface and solidify, the molecules in the solution must approach the molecules on the crystal surface and bond by hydrogen bonds. Therefore, it is considered that the factors that affect the movement of the molecules in the solution and the hydrogen bonds between the solid and the liquid molecules also affect the structure of the formed crystal.

The present inventors have found that by appropriately changing the crystallization conditions of sucrose, the ratio of the crystal form of the obtained sucrose crystal can be controlled, and thereby the physical properties such as the melting point of the sucrose crystal can be adjusted. Factors that determine the crystallization conditions include a physical factor (environmental factor) that is a factor related to molecular motion and a chemical factor (impurity factor) that is a factor related to hydrogen bonding.

Examples of physical factors (environmental factors) include a crystallization solvent, a supersaturation degree, and temperature.

As described above, the melting point and DSC results of the ethanol method crystal and the decoction method crystal were different between the two kinds of crystals, and it was found that the solvent had an influence on the structure of the sucrose crystal. it is obvious. The solvent molecules form hydrogen bonds not only between solvent molecules but also with sucrose molecules. From the results shown in FIG. 1, the hydrogen bond between sucrose and ethanol inhibits the formation of X-form and Y-form in ethanol, and therefore, the peaks on the low temperature side (about 150 ° C.) derived from them in the formed crystals. It can be seen that the melting point disappears and the high melting point is exhibited.

It is considered that the supersaturation degree and temperature of the supersaturated sugar solution also influence the molecular motion of the solvent and sucrose and the formation of hydrogen bond.

As impurities which are chemical factors,
Examples include sugars, organic acid salts, amino acid salts, inorganic salts, etc.
Be done. The site where the sucrose molecule is hydrogen bonded is δ⁻There
Is δ ⁺Is polarized to. Add the above impurities to the supersaturated sugar solution.
By adding, the polarized region is
It is affected and also affects the structure of the resulting crystal.

Examples of the saccharides include glucose and phosphorus.
Lactose, mannose and other monosaccharides, raffinose, ma
Lactose and other oligosaccharides, starch, dextran and other oligosaccharides
Examples include sugars. Examples of the organic acid salts include, for example,
Lycolic acid, levulinic acid, lactic acid, acetic acid, formic acid, aconic acid
Examples thereof include salts of tonic acid and the like. As the amino acid salts,
For example, salts of aspartic acid and the like can be mentioned. Also, above
Examples of the inorganic salts include cations that make up the inorganic salt.
And then Na⁺, K⁺, Ca²⁺, Mg²⁺Etc.
Cl is used as an anion forming an inorganic salt.⁻, CO_Three
  ^2-, PO_Four ^2-, SO_Four  ^2-Etc.

As an example of impurities, KCl was added to the sample granulated sugar solution (KCl content was 1% of the granulated sugar content), and sucrose crystals were prepared from the solution by the decoction method. The melting point of the crystal was 185 ° C., which was higher than the melting point of the infusion method crystal obtained from a solution containing no KCl. The DSC analysis result of this KCl-added crystal is shown in FIG. Compared to the case without KCl addition in FIG. 1, peaks near 150 ° C. and 160 ° C. disappear. The site of hydrogen bond of sucrose molecule is polarized to δ ⁻ or δ ⁺ , and that site is naturally K ^+.
Or it is affected by Cl ⁻ . And, it also affects the structure of the obtained crystal.

As described above, in the present invention, the crystal structure of sucrose obtained can be controlled by adjusting the conditions for sucrose crystallization. Thereby, the physical properties such as the melting point of the sucrose crystal can be adjusted, and sugar having physical properties according to the application can be realized.

In the above-mentioned embodiment, the case of adjusting the melting point as a physical property of sugar has been described as an example.
It can be widely applied to control the physical properties of sucrose by controlling not only the melting point but also the solubility, hardness, reactivity, etc. of the crystalline form of sucrose.

[0038]

EXAMPLE In this example, crystals were prepared under various crystallization conditions in order to obtain sucrose crystals having different structures, and the obtained crystals were analyzed by DSC to determine the endothermic curve shape (X-form,
The relationship between the appearance of endothermic peaks due to the disintegration of the Y-form and the Z-form) and the melting point of the crystals and the crystallization conditions was investigated.
Also, consideration was given to the influence of the crushing degree and particle size of sucrose crystals for DSC analysis on the analysis results.

Preparation of sucrose crystals under different crystallization conditions First, sucrose crystals were obtained by changing the solvent used for crystallization, and the differences in melting point and DSC analysis result were discussed.

As a sample sugar for preparing sucrose crystals, a reagent sucrose (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) and a raw sugar (produced in Australia) were used. Reagent sucrose has a water content of 0.007% (measured by Karl Fischer method) and a reducing sugar of 0.004% (measured by Offner method). Color value is 3.9
IU (ICUMSA unit), electric conductivity ash content is 0.00
It was 15% (measured by the ICUMSA method). The water content of the raw sugar is 0.22%, the reducing sugar is 0.36%, and the color value is 25.
02 IU, electric conductivity ash content was 0.26%.

Experimental Example 1 The reagent sucrose was dissolved in purified water to prepare a supersaturated sugar solution. Crystal nuclei were generated from this supersaturated sugar solution by impact, and defrosting was performed at 52 ° C. for 1 hour using an automatic crystal can to grow crystals. Then, sucrose crystals were obtained by centrifugal filtration. The crystals thus obtained are referred to as "purified water method crystals".

Experimental Example 2 When preparing a supersaturated sugar solution,
Sucrose crystals were obtained in the same manner as in Experimental Example 1, except that 1% by weight of potassium chloride was added to the reagent sucrose. The crystal thus obtained is referred to as "KCl-added crystal".

Experimental Example 3 Instead of the reagent sucrose,
Sucrose crystals were obtained in the same manner as in Experimental Example 1 except that the raw sugar was dissolved in purified water to prepare a supersaturated sugar solution.
The crystals thus obtained are referred to as "raw sugar-derived crystals".

Experimental Example 4 Reagent Sucrose was dissolved in 96% ethanol. As 96% ethanol, 99% synthetic undenatured ethanol manufactured by Shinwa Alcohol Sangyo Co., Ltd. was diluted with purified water. The reagent sucrose was dissolved by heating and then cooled to room temperature to obtain a supersaturated sugar solution. Generate crystal nuclei by ultrasonic stimulation, then, while rotating and stirring in an eggplant-shaped flask at about 30 ° C., grow crystals while occasionally concentrating,
The crystals formed were collected by centrifugal filtration. The crystals thus obtained are called "ethanol-method crystals".

<Sieving and Crushing of Sucrose Crystals for DSC Analysis> The sucrose crystals obtained as described above were adjusted in particle size by sieving for DSC analysis. For the purified water method crystals, first, the prepared crystals are sieved to obtain a fraction of 100 to 200 mesh (“100 to 20
This is referred to as "0 mesh crystal". ) And a fraction having a particle size larger than 10 mesh (referred to as “10 mesh or more crystals”).
Got The purified water method 100-200 mesh crystals were crushed with an agate mortar until they became powdery by visual observation to prepare "powder crystals", and the powder crystals were further finely crushed to prepare "fine powder crystals".

Crystals of 10 mesh or more are roughly crushed and sieved to obtain 10-16 mesh, 16-32 mesh, 32-
Fractions of 35 mesh, 35-42 mesh, 42-48 mesh, 48-100 mesh and 100-200 mesh were obtained. The crushed crystals are called "crushed crystals",
For example, crushed crystals of 100-200 mesh are treated as "100-200".
"200 mesh crushed crystal".

As will be described later in detail, with respect to crystals other than the purified water method crystals, 100 to 100 obtained by sieving the prepared crystals.
200 mesh crystals were used for DSC analysis.

<Measurement of melting point of sucrose crystals> 100-200 mesh crystals prepared under various conditions were packed in a capillary tube, and the capillary tube was immersed in a well-stirred oil bath to raise the oil bath temperature at 1 ° C / min. While measuring the melting point. The oil bath temperature was measured with a double tube standard thermometer and the capillaries filled with crystals were attached to the thermometer. The melting start temperature at which a part of the crystal started to melt and the melting completion temperature at which the crystal completely melted and became transparent were measured.

<DSC Analysis of Sucrose Crystals> For DSC analysis, a differential scanning calorimeter Pyris 1 (PerkinElmer, Ct., U
SA) was used. The measurement was performed by filling about 4 mg of crystals in an aluminum container and aerating nitrogen gas at 20 cm ³ / min at a temperature rising rate of 10 ° C./min.

For the purified water method 100 to 200 mesh crystal, the following temperature rising method analysis was also performed. First, heat from 85 ° C to 155 ° C at a heating rate of 10 ° C / minute, and then at the highest temperature decreasing rate setting (500 ° C / minute), 1
After quenching from 55 ℃ to 85 ℃, hold at 85 ℃ for 3 minutes, and then from 85 ℃ to 210 at a heating rate of 10 ℃ / min.
Heated to ° C.

Regarding the influence of the degree of crushing and the size of particles on the DSC analysis results First, the influence of the degree of crushing of sucrose crystals and the size of particles on the DSC analysis results was examined. The results of the DSC analysis of the purified water method 100-200 mesh crystals, powder crystals and fine powder crystals are shown in FIG.

The endothermic curves of the purified water method 100-200 mesh crystals show that the crystals are around 153 ° C., around 160 ° C. and 172 °
An endothermic peak is seen near ℃, and the three endothermic peaks correspond to the disintegration of the X-, Y-, and Z-forms in the crystal, respectively. In the endothermic curve of the powder crystal, most of the endothermic peaks due to the disintegration of the X-form and the Y-form disappeared. With fine powder crystals,
The endothermic peak formed by the disintegration of the X form and the Y form was further reduced, and the endothermic peak derived from the disintegration of the Z form moved to around 183 ° C.

From these results, the X-form and the Y-form are Z
Since the binding force between sucrose molecules is weaker than that of the body, it is considered that the sucrose molecules are more likely to be broken by mechanical force due to mortar crushing or frictional heat. Further, in the endothermic curve of the fine powder crystals, the endothermic peak derived from the disintegration of the Z-form shifted from around 172 ° C to around 183 ° C, so the Z-form originally disintegrates at high temperature (at least 180 ° C or higher), When the X-form or Y-form that disintegrates at a lower temperature is mixed, the Z-form collapses on the low temperature side (1
It is thought that the temperature will shift to around 72 ° C). Thus, when the crystal is finely crushed in the DSC analysis of the sucrose crystal, the original crystal structure cannot be analyzed.

Next, in order to investigate the influence of the crystal grain size on the DSC analysis, the results of DSC analysis of the crushed crystals of purified water method crystals of various mesh sizes are shown in FIG. For comparison, the endothermic curve of the 100 to 200 mesh crystal (non-crushed crystal) in FIG. 3 is also shown in FIG. 10
Comparing the crushed crystals of 0 to 200 mesh with the endothermic curves of the non-crushed crystals, the peak position corresponding to the Z-body of the crushed crystals is slightly higher than the peak position of the non-crushed crystals, but both curves are The parts are similar. When the crystal is crushed as described above, the X-form and the Y-form are more easily broken than the Z-form. However, in the crushing up to about 100 to 200 mesh, compared with the case of crushing into powder or fine powder, It is considered that the influence of crushing was small because the ratio of the crushed surface to the crystal (increase in specific surface area) was relatively small. Thus, with 100-200 mesh crystals, crushing does not significantly affect the analysis of the crystal structure by DSC analysis.

Comparing the endothermic curves of the crushed crystals of various mesh sizes shown in FIG. 4, the number of endothermic peaks increased from two to three as the crystal size decreased. It is considered that the change in the shape of this endothermic curve is affected by the crushing of crystals, but in addition to that, large crystals were analyzed by DSC.
Measuring aluminum sample container (diameter: 6.35 mm,
Height when filled with about 4 mg of crystals: about 1.6 mm)
When packed in, it is possible that the space becomes large, the wall effect of the container becomes large, and the heat transfer becomes worse than in the case of a small crystal.

As described above, when performing sucrose crystal DSC analysis, the size of the crystal and the degree of crushing affect the analysis results. However, if a crystal of 100 to 200 mesh is used, the original crystal can be analyzed, and even when the crushed crystal is mixed, the same analysis result as that of the non-crushed crystal can be obtained.
For this reason, the subsequent DSC analysis is 100-200.
It was performed on the crystals of the mesh.

There is also a report that sucrose crystals always have water of crystallization, and this water of crystallization causes the melting point of sucrose crystals to fluctuate. If the trace amount of water stored in the crystals affects the melting point, it should also affect the endothermic peak of the DSC analysis. So, 100-
After the 200-mesh crystal was sufficiently dried in a desiccator, DSC analysis was conducted, and it was confirmed that the same endothermic peak as before drying was obtained although the result is not shown here.

Confirmation that peak of endothermic curve originates from decay of X-, Y- or Z-form Next, confirmation that peak of endothermic curve originates from decay of X-, Y- or Z-form. did.

In FIG. 5, endothermic curve A of DSC analysis
Is the same as the endothermic curve of the purified water method 100-200 mesh crystal in FIG. 3, and shows X-form, Y-form and Z-form in the crystal.
There are three peaks corresponding to body collapse. In order to confirm that these endothermic peaks are due to the collapse of the crystal structure, in the DSC analysis, those heated to the appearance of the endothermic peaks derived from the decay of the X-form (ripening curve B), immediately followed by rapid cooling The result of reheating (endothermic curve C) is shown. For reference, an example of the analysis result of the candy-like sucrose (endothermic curve D) is also shown in FIG. This candy-like sucrose was obtained by placing the reagent sucrose in a test tube, heating it in an oil bath, and rapidly cooling it immediately after the crystals were completely melted.

In the case of candy-like sucrose, the endothermic curve gradually increased with increasing temperature, no large endothermic peak appeared, and a small peak appeared around 150 ° C. In general, melting of an amorphous solid (amorphous state) does not occur at a constant temperature and pressure, and its change is continuous. Therefore, from the endothermic curve D, candy-like sucrose has a very small amount of crystal parts (small endothermic peak near 150 ° C).
It can be seen that it is an amorphous solid having. The candy-like sucrose is obtained by rapidly cooling liquid sucrose in which molecules are freely moved by heating and melting, and is a solid mass in an amorphous state.

On the other hand, amorphous sucrose obtained by freeze-drying a sucrose solution is obtained by sublimating water molecules in a frozen state of an aqueous solution of sucrose (a state in which many water molecules exist between sucrose molecules). It has been removed, and it is considered that there is a space between the sucrose molecules rather than a mass of sucrose molecules. Also, the molecules in candy-like sucrose are difficult to move freely because they are lumps even if they absorb energy due to temperature rise, but with freeze-dried products with a space between molecules, It is considered that the heated molecules can move relatively easily, and an ordered arrangement (crystallization) of the molecules occurs due to intermolecular hydrogen bonding (exothermic phenomenon).

Purified water method D of 100-200 mesh crystals
In SC analysis, when reheated after the collapse of the X body (endothermic curve C in FIG. 5), the peaks due to the decay of the X body and the Y body disappeared, and a gentle rising curve was drawn, resulting in the collapse of the Z body. Only the derived peaks appeared. If it is rapidly cooled after the appearance of the peak corresponding to the X-form, the molecules whose crystal structure has collapsed due to the X-form collapse will solidify before forming the original crystal structure, and that part will become a candy-like form. It is considered that the peak corresponding to the X-form did not appear when the temperature was high. However,
The slope of the endothermic curve C is larger than the slope of the endothermic curve D of candy-like sucrose at the position of the peak (around 153 ° C.) corresponding to the decay of the X-form. From this fact, when heated until the peak derived from the decay of the X-form appears, a part of the X-form remains without decay, or is partially rearranged and crystallized during quenching. it is conceivable that. Further, in the endothermic curve C, the peak corresponding to the disintegration of the Y-form disappeared, and the curve became a gentle rising curve. Originally, the Y body should not collapse at the collapse temperature of the X body, but when the X body and the Y body are mixed, it is considered that a part of the adjacent Y body collapses when the X body collapses.

From the above, it was confirmed that the three peaks in the endothermic curve A were due to the decay of the X-, Y- and Z-forms.

DSC analysis of sucrose crystals prepared under different conditions The DSC analysis results of the sucrose crystals of Experimental Examples 1 to 4 prepared under different conditions are shown in FIG. In addition, Table 1 shows the melting point measurement results of the sucrose crystals subjected to DSC analysis.

[0065]

[Table 1]

As is clear from FIG. 6 and Table 1, the melting point of the purified water method crystal was the lowest, and the melting point was higher in the order of the ethanol method crystal, the KCl addition method crystal and the starting sugar-derived crystal. Therefore, the smaller the amount of X-form and Y-form present in the crystal, the higher the melting point.

Since the purified water method crystals have a large amount of the X-form and the Y-form, the crystal lumps cannot be kept at around 158 ° C. and the lumps begin to crumble to become liquid, but the Z-form remains. Therefore, the crystals do not completely dissolve up to around 166 ° C., and the liquid does not become transparent.

On the endothermic curve of the ethanol-method crystal, no peak derived from the decay of the X-form and the Y-form appeared, and a gentle peak thought to be derived from the decay of the Z-form appeared at around 182 ° C.

Both the purified water method crystal and the ethanol method crystal were prepared from a highly pure reagent sucrose solution, and impurities contained in both crystals were extremely small. Nevertheless, the structures of the two crystals are clearly different from the DSC analysis and the melting points are different. It is clear that the solvent influences the structure of the sucrose crystals produced. The solvent molecules (water or ethanol) form hydrogen bonds not only between solvent molecules but also with sucrose molecules. From the results shown in FIG. 6, in ethanol, the hydrogen bond between sucrose and ethanol inhibits the formation of X-form and Y-form. It is presumed that a high melting point was exhibited due to disappearance in the vicinity and around 160 ° C.).

The influence on the structure of the sucrose crystal differs depending on the concentration of ethanol. For example, when 50% ethanol is used as the solvent of the supersaturated sugar solution, the peak on the high temperature side (around 190 ° C.) disappears, and the peak on the low temperature side (around 150 ° C. and 160 ° C.) is shown. Have been confirmed by these experiments.

In the KCl-added crystal, a small endothermic peak derived from the Y-form disintegration and a peak corresponding to the Z-form disintegration, which is slightly sharper than the peak appeared in the ethanol-method crystal, appeared. In the endothermic curve of the raw sugar-derived crystals, Z was around 190 ° C.
A sharp peak due to body collapse appeared. From this, it can be said that the structure of the sucrose crystal is affected by impurities in the supersaturated sugar solution in addition to the types of solvent (water and ethanol) used for crystallization. It is considered that the potassium ion or chloride ion inhibits the formation of the X-form and the Y-form, and the impurities in the raw sugar contain a component that strongly inhibits the formation of the X-form and the Y-form.

On the other hand, in the crystal derived from the raw sugar, since the X-form and the Y-form are scarcely present, the crystal state does not change up to 182 ° C., at which temperature the Z-form begins to collapse and 186 ° C.
Melts completely in the vicinity. The temperature range from the start of melting to complete melting was about 7.5 ° C for the purified water method crystals, while it was about 4.0 ° C for the raw sugar-derived crystals. It can be seen that this melting temperature range corresponds to the sharpness of the endothermic peak in the DSC analysis. The complete melting temperature in the melting point measurement is DS
It was lower than the temperature of the endothermic peak corresponding to the disintegration of the Z form in C analysis. The reason for this phenomenon is
The rate of temperature rise in DSC analysis (10 ° C / min) is fast, the temperature rise of the crystal mass during folding is delayed, and the position of the endothermic peak apparently shifts to the high temperature side, or it is macroscopic in the melting point measurement. It can be mentioned that some Z bodies still remain at the time when they seem to have melted.

Effect of Potassium Chloride Concentration in Supersaturated Sugar Solution on Structure of Sucrose Crystals Produced From the above-mentioned experiment, potassium chloride (KC
It was found that l) influences the structure of the produced sucrose crystals. Therefore, next, the effect of changing the KCl concentration was investigated.

<Experimental Example 5> KC for reagent sucrose
The addition ratio of 1 is 0.01% by weight, 0.05% by weight,
Sucrose crystals were obtained in the same manner as in Experimental Example 2 described above except that the contents were changed to 0.1%, 0.5% and 1%.

The melting point of the obtained sucrose crystals was measured and DSC analysis was performed. The results of the DSC analysis are shown in FIG. 7, and the melting points are shown in Table 2.

[0076]

[Table 2]

As is clear from FIG. 7, KCl in the solution
As the concentration became higher, the endothermic peaks due to the disintegration of X-form and Y-form of the endothermic curve of the sucrose crystal prepared from the sugar solution became smaller. Therefore, it is clear that potassium ion or chloride ion influences the formation of the crystal structure of sucrose. Presumably, when the sucrose molecule in the solution tries to bond to the sucrose molecule on the crystal surface by hydrogen bond, the site where the sucrose molecule hydrogen bond is polarized to δ ⁻ or δ ⁺ ,
The site is naturally affected by K ⁺ or Cl ⁻ . These K ⁺ or Cl ⁻ ions inhibit hydrogen bonding,
It is considered that the formation of X body and Y body was inhibited by the influence.

Further, as shown in Table 2, the higher the KCl concentration in the supersaturated sugar solution, the higher the melting point of the produced crystal. This phenomenon cannot be explained by the melting point lowering phenomenon due to ordinary impurities, but it can be explained by assuming that potassium ion or chloride ion is a component that inhibits the formation of X-form and Y-form. There are many other components that affect the formation of sucrose crystals, such as potassium or chloride ions.

Effect of impurities on melting point of produced sucrose crystals <Experimental Example 6> When the reagent sucrose was dissolved in purified water to prepare a supersaturated sugar solution, the substances shown in Table 3 were added as impurities.
It was added to the reagent sucrose in the ratio shown in the table. Crystal nuclei were generated from this supersaturated sugar solution by impact, and defrosting was performed at 52 ° C. for 1 hour using an automatic crystal can to grow crystals. Then, sucrose crystals were obtained by centrifugal filtration.

Then, DSC analysis was performed on the obtained sucrose crystals. The values of the endothermic peaks obtained as a result of the DSC analysis are shown in Table 3 together with the substances and concentrations added as impurities.

[0081]

[Table 3]

As is clear from Table 3, by adding an impurity to the supersaturated sugar solution, the ions of the impurity influence the formation of the crystal structure of sucrose. When the sucrose molecule in the solution tries to bond to the sucrose molecule on the crystal surface by hydrogen bond, the site of hydrogen bond of the sucrose molecule is polarized to δ ⁻ or δ ⁺ , and it is affected by the added impurity ion, so that the X , Y-form or Z-form is inhibited. Depending on the type of impurities,
It was found that the effects on the formation of the crystal structure of sucrose were different.

Effect of temperature of crystal solution on melting point of produced sucrose crystals <Experimental Example 7> Temperature of supersaturated sugar solution using ethanol as solvent was changed to 35 ° C, 42 ° C, 52 ° C, 72 ° C. Except for the above, sucrose crystals were obtained in the same manner as in Experimental Example 4.

Then, DSC analysis was conducted on the obtained sucrose crystals. The result of the DSC analysis is shown in FIG.

As is clear from FIG. 8, the temperature of the supersaturated sugar solution affects the formation of the crystal structure of sucrose. It can be seen that the temperature of the supersaturated sugar solution affects the molecular motion of the solvent and sucrose and the formation of hydrogen bonds.

[0086]

INDUSTRIAL APPLICABILITY In the present invention, the crystal structure of the obtained sugar can be controlled by adjusting the conditions for sucrose crystallization. Thereby, the melting point of sugar can be adjusted, and sugar having a melting point according to the application can be realized.

[Brief description of drawings]

[Fig. 1] DSC of decoction method and ethanol method crystals
It is a figure which shows an analysis result.

FIG. 2 is a diagram showing the results of DSC analysis for KCl-added crystal.

[Fig. 3] DS of purified water method crystals with different grinding degree
It is a figure which shows a C analysis result.

FIG. 4 is a diagram showing the results of DSC analysis for purified water method crystals of various mesh sizes.

FIG. 5 is a diagram showing a DSC analysis result for sucrose crystals obtained by changing heating conditions during DSC analysis.

FIG. 6 is a diagram showing a DSC analysis result of sucrose crystals obtained by changing crystallization conditions.

FIG. 7 is a diagram showing a DSC analysis result of sucrose crystals obtained by changing the addition ratio of KCl.

FIG. 8 is a diagram showing DSC analysis results of sucrose crystals obtained by changing the temperature of decoction.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 9/02 608 B01D 9/02 608A 609 609A 620 620 625 625A (72) Inventor Koji Kawasaki Okazaki City, Aichi Prefecture 2-10-12 Shojida

Claims (6)

[Claims] 1. A method for producing sugar having a crystallization step of growing a sucrose crystal from a supersaturated solution of a sucrose body, wherein the sucrose crystal is composed of three or more crystal forms having different melting points. A method for producing sugar, which comprises controlling a crystal form by controlling crystallization conditions and controlling a melting point of sucrose obtained. 2. The sucrose crystal comprises at least a first crystal form having a melting point of 153 ° C., a second crystal form having a melting point of 160 ° C., and a third crystal form having a melting point of 172 ° C. The method for producing sugar according to claim 1. 3. The method for producing sugar according to claim 1, wherein in the crystallization step, the crystal form is controlled by adding impurities to the supersaturated solution. 4. The method for producing sugar according to claim 3, wherein the impurities are sugars, organic acid salts, amino acid salts or inorganic salts. 5. The method for producing sugar according to claim 1, wherein in the crystallization step, the crystal form is controlled by adjusting the solvent of the supersaturated solution. 6. The method for producing sugar according to claim 1, wherein in the crystallization step, the crystal form is controlled by adjusting the temperature of the supersaturated solution.