WO2014044512A1 - Method comprising continuous crystallization of isomaltulose - Google Patents

Description

 A process comprising a continuous crystallization of isomaltulose

Field of the invention

The invention relates to a process comprising a continuous crystallization of isomaltulose.

State of the art

The known processes for the production of highly pure isomaltulose are based on

Isomerization of an aqueous sucrose solution consisting of "white sugar" or

"Refined sugar", therefore from purified sucrose, was used, and a separation of isomaltulose from the isomerization mixture via a batchwise evaporation of the solvent with a downstream batch-wise operated cooling crystallization.Providing processes are described in DE3241788 and EP0983374.

To increase the yield, the mother liquor is further evaporated and subjected to a second cooling crystallization. Alternatively, the mother liquor is fresher

Sucrose solution mixed and fed to another Isomerisierungstufe. To the

Process control of the crystallizations described in these processes are not high demand, since the Isomerisierungsgemisch - justified in the pure sucrose used as starting material - is a little complex and well-defined composition of which isomaltulose is easy to separate.

The previously known crystallization processes are unsuitable for separating isomaltulose from more contaminated solutions of satisfactory quality

The object of the invention was to provide a process which allows a simple separation of pure isomaltulose from complex compositions, in particular strongly colored compositions. Description of the invention

It has been found that the isomaltulose produced continuously as described below in excellent quality from complex compositions, such as

for example, isomerized thick juice, can be separated.

 In addition, it has been found that the continuous crystallization of isomaltulose has advantages in the practice of the process.

The subject of the present invention is therefore a process for continuous

Crystallization of isomaltulose comprising the process steps

 A) providing a feed solution containing isomaltulose and water,

 B) partially removing the water by evaporation to obtain a suspension of isomaltulose crystals,

 C) separating the suspension into an isomaltulose-containing solid and a mother liquor and optionally

 D) washing the isomaltulose-containing solid.

An advantage of the method according to the invention is the constant product quality due to the stationary system state.

Yet another advantage of the method according to the invention is that an increased apparatus-specific space-time yield is achieved.

 Yet another advantage of the method of the invention is the reduced need for buffer containers.

 Yet another advantage of the method according to the invention is that a complex cultivation of seed crystals for the necessary inoculation procedure can be dispensed with since, in a continuous process, seed crystals e.g. be formed by pump abrasion, collision of two particles with each other and / or with the Kristallerwandung targeted.

A further advantage of the method according to the invention is the possible energy saving, since a sucrose crystallization can be dispensed with in the context of the provision of isomaltulose. This results in a further advantage of the process according to the invention in the form of the higher specific yield based on the sucrose used.

By the term "for continuous crystallization" in connection with the

Process according to the invention is to be understood that the process according to the invention is carried out continuously. Thus, at least two process steps, for example B) and C), are carried out simultaneously. Therefore, is below the term

"Procedural step" X, Y, Z also no discrete, time-separated sequence of steps to understand, in the sense of "first complete X, then Y begin when Y completed then Z begin".

 All percentages (%) are by mass unless otherwise specified.

In process step A), a feed solution containing isomaltulose and water is provided. As already mentioned above, the original provision of isomaltulose takes place for

Process step A) as a rule via one, in particular enzymatic, isomerization of sucrose. Processes for such isomerization are for example from Proc. Res. Soc. Jpn. Sugar Refineries Technol. 33, 55-63 (1984), Zuckerindustrie 1 16, 197 (1991), the

JP03180172, EP0028900, EP0109009 and EP0049742.

To reduce the production costs and to achieve better yields based on sucrose used, it is inventively advantageous and thus preferred if the provided in step A) feed solution containing isomaltulose and water at least partially the direct Isomensierungsprodukt a sucrose-containing

Contains vegetable juice. As a result, contains the preferably used feed solution of

process according to the invention many more, not characterized and separated

Secondary components which can not be separated by conventional methods.

 The term "direct isomensation product of a sucrose-containing vegetable juice" in connection with the process according to the invention is to be understood that for the production of the isomerization product starting from a sucrose-containing plant juice no crystallization step was carried out and the plant juice was directly isomerized.

The sucrose-containing vegetable juice is preferably selected from thin juice and thick juice, the latter being particularly preferred.

 In the context of the present invention, the term "thin juice" is to be understood as meaning the product which is present in the sugar production from sugar beet or sugar cane after juice purification. "Thin juice typically contains 10-20% by weight of sucrose, based on the total juice.

The term "thick juice" is to be understood in the context of the present invention, the thickened "thin juice" containing more than 20 wt .-% sucrose based on the total juice. A preferred method according to the invention is characterized in that

Process step B) in a temperature range from 50 ° C to 70 ° C, preferably from 55 ° C to 65 ° C, more preferably from 58 ° C to 62 ° C and in a pressure range from 70 mbar to 200 mbar, preferably from 100 mbar to 180 mbar, more preferably from 1 10 mbar to 140 mbar is performed. In particular, it is preferred in this context that, in the process according to the invention, process step B) is carried out in a temperature range from 58 ° C. to 62 ° C. and in a pressure range from 1 10 mbar to 140 mbar.

By varying the degree of evaporation different solids contents or yields can be approached, this can be controlled for example over the residence time in process step B). It is advantageous and thus preferred if in process step B) so much water is removed, so that based on the suspension, these 20 wt .-% to 70 wt .-%, preferably 30 wt .-% to 65 wt .-%, more preferably contains from 40 wt .-% to 60 wt .-% isomaltulose.

In method step C), all methods known to those skilled in the art for the separation of solids from liquids can be used, such as, for example, centrifugation, sedimentation, decantation, separation in the gravitational field and filtration. A process preferred according to the invention is characterized in that the separation in process step C) takes place by centrifugation.

It is inventively preferred that the washing in process step D) is carried out with water, in particular with water, which has a temperature of 20 ° C to 90 ° C, preferably from 30 ° C to 80 ° C, more preferably from 50 ° C to 70 ° C.

In order to increase the yield of isomaltulose and to avoid product losses, it is inventively preferred that the liquid used in step D) for washing, in particular the water used for washing, the feed solution of

Process step A) is supplied.

An inventively preferred method is thus characterized in that the feed solution of process step A) containing isomaltulose and water in

Process step D) for washing used liquid contains; The feed solution particularly preferably contains the liquid used for washing in process step D) and the direct isomerization product of a sucrose-containing vegetable juice. In order to achieve the same technical effect, it is preferred that the method according to the invention is characterized in that it additionally comprises the method steps

E) cooling the mother liquor from process step C) to obtain a second

 Suspension of isomaltulose crystals,

 F) separating the suspension into a second isomaltulose-containing solid and a second mother liquor and optionally

 G) dissolving the second isomaltulose-containing solid in the feed solution of

 Process step A).

In order to drive this preferred method as energetically favorable, it is preferred that in addition to step B) also step C) in one

Temperature range from 50 ° C to 70 ° C, preferably from 55 ° C to 65 ° C, more preferably from 58 ° C to 62 ° C and in a pressure range from 70 mbar to 200 mbar, preferably from 100 mbar to 180 mbar, especially is preferably carried out from 1 10 mbar to 140 mbar.

In particular, it is preferred in this context that, in addition to process step B), process step C) is also carried out in a temperature range from 58 ° C. to 62 ° C. and in a pressure range from 110 mbar to 140 mbar. A preferred process according to the invention is characterized in particular by the fact that in process step E) the mother liquor from process step C) is heated to 10 ° C. to 30 ° C., preferably to 15 ° C. to 25 ° C., more preferably to 18 ° C. to 22 ° C. is cooled.

Process step E) is carried out in particular at atmospheric pressure, therefore at 0.90 to 1, 10 bar absolute.

In process step F) of the preferred process according to the invention, the same processes for the separation of solids from liquids can be used as in process step C) of the process according to the invention to obtain a second isomaltulose-containing solid and a second mother liquor; Process step F) is preferably carried out at 10 ° C to 30 ° C, preferably at 15 ° C to 25 ° C, more preferably at 18 ° C to 22 ° C.

The second isomaltulose-containing solid can be further processed into end products or - as proposed - in process step G) in the feed solution of process step A) be added, it being preferred that the second isomaltulose-containing solid after being added to the feed solution of process step A) is present in this dissolved.

In a method which is preferred according to the invention, method step G) is carried out. A method preferred according to the invention is thus characterized in that

Feed solution of process step A) containing isomaltulose and water containing the second isomaltulose-containing solid from process step F); Particularly preferably, the feed solution contains the second isomaltulose-containing solid from process step F), the liquid used for washing in process step D) and the direct

Isomerization product of a sucrose-containing vegetable juice; more preferably, the feed solution consists of the three components and water.

In the examples given below, the present invention is described by way of example, without the invention, whose scope of application is apparent from the entire description and the claims, referred to in the examples

Embodiments should be limited.

The following figures are part of the examples:

Figure 1: Exemplary technical process management

Examples:

Continuous crystallization of isomaltulose from isomerized thick juice

Crystallization of the isomaltulose was performed using a Mixed Suspension Mixed Product Removal (MSMPR) apparatus. The effective usable volume is 3 liters. For the solid-liquid separation and crystal washing, a filter cage centrifuge from Cepa with a basket diameter of 200 mm was available. The filter cake could be washed with ultrapure water via a plug-in tube. step 1

The starting material used was a thick juice feed stream isomerized with Protaminobacter rubrum. The isomerized thick juice has a dry matter content of about 41% by weight. The composition with respect to the sugars and isomerization product contained is shown in Table 1.

 Table 1 Composition of isomerized thick juice

The isomerized thick juice was tempered in the receiver to a temperature of about 60 ° C. A volume flow of 2 kg / h was set via the piston metering pump. The isomerized thick juice was submerged at a temperature of 60 ° C

Feeding tube retracted into the circulated crystal suspension. The crystallizer was at a temperature of about 60 ° C and a pressure of 1 10 - 140 mbar abs. set a distillate stream of 1 kg / h. As a result of the evaporation of water, the solution was continuously supersaturated to a constant value. The supersaturation in the crystallizer was degraded with the help of the already existing crystals and crystal nuclei, so that an efficient crystal growth took place. From the crystallizer, a suspension flow of about 1 kg / h was withdrawn batchwise every hour.

The crystal suspension was introduced into the centrifuge at a speed of 500 rpm. The solid-liquid separation was then carried out for 2 minutes at a speed of 1000 rpm. The mother liquor obtained in the solid-liquid separation was weighed. From the difference between filled mass and mother liquor a theoretical amount of solids was determined. Based on the theoretical amount of solids, the solid was washed with 10% ultrapure water at a speed of 500 rpm. For dehumidification, the speed of the centrifuge was increased to 4000 rpm for about 2 minutes. Following was the solid from the centrifuge be removed. On average, 0.40 kg / h of solid is obtained from 1 kg / h suspension. At a suspension density of 1.3 kg / L and an average hold-up of 3.5 L, this corresponds to a residence time of 4.5 hours.

 The separated solid had the following composition:

 Table 2 Composition of the washed solid

For stage 1, an isomaltulose yield of 62% can be calculated.

The separated mother liquor of stage 1 has the following composition:

 Table 3 Composition of the mother liquor stage 1

Level 2

To increase the yield, the mother liquor could then be treated in a further stage. This was carried out by means of a so-called cooling crystallization from 60 ° C. to about 20 ° C. In the experiment, the mother liquor was tempered for this purpose in the feed template at 60 ° C and on the

Piston dosing pump retracted into the crystallizer at normal pressure. The feed stream was 0.6 kg / h. The crystallizer was run in continuous operation at 20 ° C. By the Lowering the temperature, the saturation limit of the solution was exceeded. The generated supersaturation was degraded in the crystallizer by crystal growth on the primary particles formed. From the crystallizer, a suspension having a solids content of about 27% was taken. The crystal suspension was introduced into the centrifuge at a speed of 500 rpm. The solid-liquid separation was then carried out for 2 minutes at a speed of 4000 rpm. Crystal washing of the solid was dispensed with. The yield of the second crystallization stage is at a separated solid of 0.137 kg / h about

20.1%. For the overall process, this results in an overall yield of 85.1%. Hereinafter, the compositions of the mother liquor and the solid are the second

Crystallization stage listed.

 Table 4 Composition of the mother liquor stage 2

Table 5 Composition of solids Stage 2 Example of a technical process management

A possible technical process management of a preferred method according to the invention is shown in FIG. 1:

The feed solution containing isomaltulose (1) is used at the beginning of the process to remove the non-washed solid (14) from crystallization stage S2 (D) and the

To dissolve wash water (10) from the crystal wash (B). The total stream (3) is then retracted into the evaporation crystallization S1 (A). Here, the solubility of isomaltulose is exceeded by evaporation at 60 ° C and a pressure of 1 10 -140 mbar of an appropriate water content (5), so that crystallized isomaltulose and as suspension (4) from the evaporation crystallization (A) in the solid-liquid -Trennung / crystal washing (B) can be driven. In solid-liquid separation / crystal washing (B), the

Isomaltulose crystals separated from the mother liquor (1 1). The mother liquor-containing solid is washed with ultrapure water (7). The washed crystals (6) are moved to the product preparation (C). The product preparation can be carried out as drying or as a solution station with ultrapure water (9). To increase the yield, the mother liquor (11) is fed to a cooling crystallization (D). Here, the solution is cooled in a continuous process from 60 ° C to a temperature of 20 ° C. The solubility limit of isomaltulose is exceeded so that isomaltulose

crystallized out and a suspension (12) is formed. The suspension (12) is fed from the cooling crystallization (D) to the solid-liquid separation (E). Herein, the generated crystals (14) are separated from the mother liquor (13). The crystals are not washed. The mother liquor (13) leaves the process. The solid (14) becomes

Recrystallization in isomaltulose feed stream (1) redissolved.

 Table 6 Material flow table

Claims

claims 1 . Process for the continuous crystallization of isomaltulose comprising  steps  A) providing a feed solution containing isomaltulose and water,  B) partially removing the water by evaporation to obtain a suspension of isomaltulose crystals,  C) separating the suspension into an isomaltulose-containing solid and a  Mother liquor and optionally  D) washing the isomaltulose-containing solid. 2. Method according to claim 1,  characterized,  that the feed solution of process step A) at least partially the direct  Isomerization of a sucrose-containing vegetable juice, especially thin juice or thick juice contains. 3. Method according to at least one of the preceding claims,  characterized,  that process step B) in a temperature range from 50 ° C to 70 ° C, preferably from 55 ° C to 65 ° C, more preferably from 58 ° C to 62 ° C and in a pressure range from 70 mbar to 200 mbar, preferably from 100 mbar to 180 mbar, more preferably from 1 10 mbar to 140 mbar is performed. 4. The method according to at least one of the preceding claims,  characterized,  the separation in process step C) takes place by centrifugation. 5. The method according to at least one of the preceding claims,  characterized, that the washing in process step D) is carried out with water. Method according to at least one of the preceding claims, characterized the liquid used for washing in process step D) is fed to the feed solution of process step A). Method according to at least one of the preceding claims, characterized, that it additionally comprises the method steps  E) cooling the mother liquor from process step C) to obtain a second  Suspension of isomaltulose crystals,  F) separating the suspension into a second isomaltulose-containing solid and a second mother liquor and optionally  G) adding the second isomaltulose-containing solid to the feed solution of process step A). Method according to claim 7, characterized, that in process step E) the mother liquor from process step C) is cooled to 10 ° C. to 30 ° C., preferably to 15 ° C. to 25 ° C., particularly preferably to 18 ° C. to 22 ° C. Method according to claim 7 or 8, characterized, the feed solution of process step A) comprises the second isomaltulose-containing solid from process step F), the liquid used for washing in process step D) and the direct isomerization product of a sucrose-containing vegetable juice.