Novel lactitol production process

Abstract

The invention discloses a novel lactitol production process which comprises the following steps: dissolving lactose, carrying out hydrogenation reaction on a dissolved solution, filtering a hydrogenated solution by a ceramic membrane, decolorizing filtrate particles by a carbon column, concentrating a feed liquid after ion exchange of a decolorized solution, carrying out chromatographic separation on a concentrated solution, adding a seed crystal into a chromatographic extracting solution, concentrating, melting and granulating a concentrated material, and drying a granulated product. And grinding the dried product, and screening the ground product to obtain a finished product. According to the method, the generation of fine crystals and pseudo crystals in the crystallization process of lactitol can be avoided, the constraint of a traditional crystallization process is avoided, and the environment is not influenced while the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of lactitol processing, in particular to a novel production process of lactitol. Background Art

[0002] Lactitol is a common sweetener, also known as sweet prunes. It is a polyol that has a sweet taste but very low calories. Lactitol can be extracted from natural products such as fruits, vegetables and nuts, or obtained through chemical synthesis. Lactitol is a common sweetener with the characteristics of low calories and poor absorption, making it suitable for diabetics and people who pursue health.

[0003] Lactitol has good thermal stability and acid-base stability. It is not easy to decompose, change color, and is acid- and alkali-resistant, which are not possessed by oligosaccharide prebiotics. Lactitol is not easy to absorb moisture: Lactitol is a crystalline powder. Among functional sugar alcohols, lactitol is one of the few sugar alcohols that is not easy to absorb moisture. Compared with the generally hygroscopic oligosaccharides, lactitol is less likely to absorb moisture, which is very helpful for the product to resist caking. Lactitol has a mild effect and no adverse reactions. Lactitol has good gastric acid resistance: Compared with oligosaccharides, lactitol has better acid resistance and is basically not decomposed in gastric acid. Therefore, it has a high retention rate and can be used more by probiotics.

[0004] At present, the production process of lactitol is a traditional crystallization process. The production process described in patent number CN110818752A can perform multiple crystallizations by using mother liquor recycle. Due to the existence of multiple concentration and cooling process flows, the energy consumption is large and there is part of the mother liquor discharged, which contains a large amount of lactitol. Patent number CN103980329A introduces a process for preparing lactitol crystals, which is to purify the crystallization mother liquor by sequential simulated moving bed chromatography after the first crystallization, and then continue to crystallize the crystallization mother liquor after sequential simulated moving bed chromatography purification. This process will cause the process to be more complicated and there will be a large amount of lactitol in the chromatographic raffinate, resulting in a decrease in the system yield of lactitol. Summary of the invention

[0005] The purpose of the present invention is to provide a novel production process of lactitol, so as to reduce energy consumption and discharge of mother liquor in the production process, and to avoid the generation of fine crystals and pseudocrystals in the crystallization process of lactitol as much as possible, avoid the constraints of traditional crystallization process, save costs and have no impact on the environment.

[0006] To achieve the above object, the present invention provides a novel production process of lactitol, comprising the following steps:

[0007] A novel production process of lactitol comprises the following steps:

[0008] a) dissolving lactose in pure water, adding a pH regulator to adjust the pH to 7.0-8.0, adding a catalyst, and introducing hydrogen to cause a hydrogenation reaction to obtain a lactose hydrogenated liquid, wherein the addition of the pH regulator can prevent the occurrence of side reactions during the hydrogenation process;

[0009] b) filtering the lactose hydrogenated liquid to separate the catalyst to obtain a clarified lactitol solution;

[0010] c) subjecting the lactitol solution to decolorization and ion exchange to obtain a pure ion exchange liquid;

[0011] d) subjecting the ion exchange liquid to chromatographic separation to obtain a chromatographic extract and a chromatographic raffinate. In the present invention, directly subjecting the ion exchange liquid to chromatographic separation can improve the purity of lactitol in the chromatographic extract to obtain a high-purity lactitol product, while making the lactitol content in the chromatographic raffinate very low, thereby reducing the waste of lactitol;

[0012] e) performing vacuum evaporation and concentration on the chromatographic extract at a concentration temperature of not less than 120° C. to obtain a concentrated solution in a molten state. Concentration under a vacuum state can reduce the evaporation temperature of water to improve the evaporation and concentration efficiency;

[0013] f) adding seed crystals to the concentrated solution under vacuum to carry out melt granulation to obtain lactitol particles; directly concentrating the high-purity chromatographic extract into a molten state and then melt granulating to obtain lactitol particles; compared with the traditional cooling crystallization process, it is not necessary to centrifuge to remove the mother liquor, which can reduce the discharge of the mother liquor and avoid the loss of lactitol in the concentrated mother liquor; the melt granulation process can directly utilize the heat of the concentration process, and does not require multiple cooling crystallizations, which can also reduce energy consumption; in addition, the melt granulation process cools evenly, which can reduce the generation of fine crystals and pseudocrystals;

[0014] g) drying, crushing and sieving the lactitol particles in sequence to obtain a product with qualified moisture content and uniform particle size.

[0015] Preferably, the concentration of the lactose solution in step a) is 45%-50%. If the concentration of the lactose solution is too low, the resin regeneration frequency in the ion exchange process will be high and further concentration will be required after subsequent ion exchange. If the concentration is too high, the pressure of the ceramic membrane and the ion exchange column will be high, resulting in a slow material transfer rate.

[0016] Preferably, the hydrogenation temperature in step a) is 110-130° C., in order to ensure process and equipment safety, the pressure is selected to be 4.0-4.5 MPa, the catalyst is a Raney nickel catalyst, and the reaction time is 1.5 h-2 h.

[0017] Preferably, in the step b), the lactose hydrogenation liquid is filtered using a ceramic membrane to obtain a ceramic clear phase and reduce the Raney nickel catalyst in the hydrogenation liquid, wherein the filtration pressure does not exceed 30 Bar.

[0018] Preferably, the ion exchange process in step c) is sequentially a primary cation exchange, a primary anion exchange, a secondary cation exchange, a secondary anion exchange, and a mixed bed ion exchange, so that the conductivity of the ion exchange liquid can be ensured to be less than 20 μs / cm.

[0019] Preferably, the water-to-solid ratio in the chromatographic separation process in step d) does not exceed 1:3, so as to more effectively increase the content of lactitol in the chromatographic extract.

[0020] Preferably, the concentration of the concentrated solution in step e) is not less than 90% to ensure that the moisture content of the concentrated solution in a molten state meets the requirements after melt granulation, and the lactitol content in the concentrated solution can also be higher. The concentration process in step e) is double-effect concentration and single-effect concentration in sequence. Double-effect concentration can save energy, and single-effect concentration can meet the concentration requirements of the final concentration.

[0021] Preferably, the particle size of the seed crystals added in step f) is 0.03-0.07 mm. Reasonable control of the particle size of the inserted seed crystals can facilitate the crystallization of lactitol particles and reduce the generation of fine crystals and pseudocrystals.

[0022] Preferably, the temperature of the melt granulation in step f) is controlled at 120-130° C. to ensure that the concentrated liquid is fully mixed and uniform.

[0023] Preferably, the process of crushing the lactitol particles in step g) is powder.

[0024] The novel lactitol production process of the present invention comprises the following steps: lactose dissolution, hydrogenation reaction of the dissolving liquid, filtration of the hydrogenating liquid by a ceramic membrane, decolorization of the filtrate by a granular carbon column, ion exchange of the decolorizing liquid, chromatographic separation of the feed liquid after the ion exchange, vacuum concentration of the chromatographic extract, melt granulation of the concentrated material, drying of the granulated product, grinding of the dried product, and screening of the ground product into a finished product. The production process of the present invention can effectively control the purity of lactitol in the chromatographic extract in the chromatographic separation step, and lactitol crystal seeds are added in the melt granulation link, which can further increase the lactitol content, thereby obtaining a high-purity lactitol product with good crystallinity. In addition, the melt granulation process can directly utilize the heat of the concentration process, does not need to be reheated, and reduces energy consumption, thereby reducing the production cost of lactitol. In addition, the concentrated solution is directly melt granulated, which avoids the generation of mother liquor. Since there is no large amount of mother liquor, the impact on the environment is reduced, the equipment investment is reduced, and the capital investment is reduced. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail in the following embodiments.

[0026] Embodiment 1:

[0027] Step a), dissolving lactose, diluting to a concentration of 45%, adding a pH regulator to adjust the pH to 8.0, adding a Raney nickel catalyst, controlling the hydrogenation temperature to 130° C., the hydrogen pressure to 4.5 MPa, reacting for 2 hours, and hydrogenating to obtain a lactose hydrogenated liquid, the purity of the hydrogenated liquid being 98.33%;

[0028] Step b), filtering the lactose hydrogenated liquid in step a) through a ceramic membrane to obtain a ceramic clear phase;

[0029] Step c), subjecting the ceramic clear phase in step b) to ion exchange in a cation-yin-yang-anion mixed bed sequence to obtain an ion exchange liquid with a conductivity of less than 20 μs / cm;

[0030] Step d), subjecting the ion exchange liquid in step c) to chromatographic separation at a water-to-solid ratio of 1:2.78 to obtain a chromatographic extract and a chromatographic raffinate, wherein the purity of lactitol in the extract is 99.43%;

[0031] Step e), concentrating the chromatographic extract in step d), wherein the double-effect concentration is to a concentration of 70%, and the single-effect concentration is to a concentration of 94%, to obtain a concentrated solution in a molten state;

[0032] Step f), melt-granulating the molten concentrated solution in step e), adding seed crystals with a particle size of 0.03 mm, and the temperature of melt-granulation is 120° C. to obtain completely solidified lactitol particles;

[0033] Step g), drying the lactitol particles in step f) to obtain dry lactitol particles with a moisture content of 0.18%, grinding the dried lactitol particles to obtain small particles of lactitol, and sieving the small particles of lactitol with a mesh size of 20-80 to obtain a lactitol product with uniform particle size.

[0034] Embodiment 2:

[0035] Step a), dissolving lactose, diluting to a concentration of 48%, adding a pH regulator to adjust the pH to 7.5, adding a Raney nickel catalyst, controlling the hydrogenation temperature to 120° C., the hydrogen pressure to 4.3 MPa, reacting for 1.5 hours, and hydrogenating to obtain a lactose hydrogenated liquid, the purity of the hydrogenated liquid being 98.24%;

[0036] Step b), filtering the lactose hydrogenated liquid in step a) through a ceramic membrane to obtain a ceramic clear phase;

[0037] Step c), subjecting the ceramic clear phase in step b) to ion exchange in a cation-yin-yang-anion mixed bed sequence to obtain an ion exchange liquid with a conductivity of less than 20 μs / cm;

[0038] Step d), subjecting the ion exchange liquid in step c) to chromatographic separation at a water-to-solid ratio of 1:2.81 to obtain a chromatographic extract and a chromatographic raffinate, wherein the purity of lactitol in the extract is 99.31%;

[0039] Step e), concentrating the chromatographic extract in step d), wherein the double-effect concentration is to a concentration of 71%, and the single-effect concentration is to a concentration of 95%, to obtain a concentrated solution in a molten state;

[0040] Step f), melt-granulating the molten concentrated solution in step e), adding seed crystals with a particle size of 0.05 mm, and the temperature of melt-granulation is 125° C. to obtain completely solidified lactitol particles;

[0041] Step g), drying the lactitol particles in step f) to obtain dry lactitol particles with a moisture content of 0.16%, grinding the dried lactitol particles to obtain small particles of lactitol, and sieving the small particles of lactitol with a mesh size of 20-80 to obtain a lactitol product with uniform particle size.

[0042] Embodiment 3:

[0043] Step a), dissolving lactose, diluting to a concentration of 50%, adding a pH regulator to adjust the pH to 7.0, adding a Raney nickel catalyst, controlling the hydrogenation temperature to 110° C., the hydrogen pressure to 4 MPa, reacting for 2.0 h, and hydrogenating to obtain a lactose hydrogenated liquid, the purity of the hydrogenated liquid being 98.17%;

[0044] Step b), filtering the lactose hydrogenated liquid in step a) through a ceramic membrane to obtain a ceramic clear phase;

[0045] Step c), subjecting the ceramic clear phase in step b) to ion exchange in a cation-yin-yang-anion mixed bed sequence to obtain an ion exchange liquid with a conductivity of less than 20 μs / cm;

[0046] Step d), subjecting the ion exchange liquid in step c) to chromatographic separation at a water-to-solid ratio of 1:2.88 to obtain a chromatographic extract and a chromatographic raffinate, wherein the purity of lactitol in the extract is 99.23%;

[0047] Step e), concentrating the chromatographic extract in step d), wherein the double-effect concentration is to a concentration of 72%, and the single-effect concentration is to a concentration of 96%, to obtain a concentrated solution in a molten state;

[0048] Step f), melt-granulating the molten concentrated solution in step e), adding seed crystals with a particle size of 0.07 mm, and the temperature of melt-granulation is 130° C. to obtain completely solidified lactitol particles;

[0049] Step g), drying the lactitol particles in step f) to obtain dry lactitol particles with a moisture content of 0.15%, grinding the dried lactitol particles to obtain small particles of lactitol, and sieving the small particles of lactitol with a mesh size of 20-80 to obtain a lactitol product with uniform particle size.

[0050] When the novel lactitol production process provided by the present invention is applied, lactose is dissolved, the dissolved liquid is hydrogenated, the hydrogenated liquid is filtered through a ceramic membrane, the filtered liquid is decolorized with a granular carbon column, the decolorized liquid is exchanged according to cations and anions, the feed liquid is concentrated after the ion exchange, the concentrated liquid is chromatographically separated, the chromatographic extract is concentrated, the concentrated material is melt-granulated, the granulated product is dried, the dried product is ground, and the ground product is sieved to obtain a finished product.

[0051] The concentration of the sugar-soluble solution prepared in step a) is 45-50% and the pressure is 4.0-4.5Mpa. If it is higher than this filtration pressure and concentration range, the color of the hydrogenated liquid is darker and the safety of the reaction needs to be ensured; if it is lower than this filtration pressure range, the hydrogenation reaction is incomplete and the reducing sugar residue is high.

[0052] In addition, the following comparative tests were conducted in this application:

[0053] Experiment 1: Five experimental groups with different concentrations were set up at the same pressure (4.0Mpa) to obtain the light transmission and reducing sugar effects of hydrogenated liquid in different experimental groups. The experimental results are as follows:

[0054] Table 1

[0055]

[0056] Experiment 2: Five experimental groups with different pressures were set up at the same concentration (45%) to obtain the light transmission and reducing sugar effects of hydrogenated liquid in different experimental groups. The experimental results are as follows:

[0057]

[0058] From the data in Table 1 and Table 2, we can conclude that:

[0059] 1) Under the same pressure, as the concentration increases, the transmittance of the hydrogenated liquid gradually decreases, and the reducing sugar gradually increases. When the concentration is reduced to 43%, the reducing sugar and transmittance change little; when it is increased to 53%, the reducing sugar and transmittance change significantly, so 45%-50% is selected as the reaction concentration.

[0060] 2) At the same concentration, as the pressure increases, the light transmittance of the hydrogenated liquid increases and the reducing sugar decreases. When the pressure is reduced to 3.7Mpa, the light transmittance and reducing sugar change significantly; when the pressure is increased to 4.8Mpa, the light transmittance and reducing sugar do not change significantly, so 4.0-4.5Mpa is selected as the reaction pressure.

[0061] In summary, the novel lactitol production process provided by the present invention has the following advantages:

[0062] 1. Through the implementation of the present invention, the recycling and multiple crystallization of mother liquor can be effectively reduced;

[0063] 2. By using the present invention, lactitol with stable quality and uniform particle size can be obtained, and the product is better.

[0064] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0065] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0066] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel production process of lactitol, characterized in that: The following steps are involved: a) dissolving lactose in pure water, adjusting the pH, adding a catalyst, and introducing hydrogen to cause a hydrogenation reaction to obtain a lactose hydrogenated liquid; b) filtering the lactose hydrogenated liquid to separate the catalyst to obtain a clarified lactitol solution; c) subjecting the lactitol solution to decolorization and ion exchange to obtain a pure ion exchange liquid; d) subjecting the ion exchange liquid to chromatographic separation to obtain a chromatographic extract and a chromatographic raffinate; e) concentrating the chromatographic extract by vacuum evaporation to obtain a concentrated solution in a molten state; f) adding seed crystals to the concentrated solution under vacuum to carry out melt granulation to obtain lactitol particles; g) drying, crushing and sieving the lactitol particles in sequence to obtain a qualified product.

2. The novel production process of lactitol according to claim 1, characterized in that: The concentration of the lactose solution in step a) is 45-50%.

3. The novel production process of lactitol according to claim 1, characterized in that: The hydrogenation temperature in step a) is 110-130° C., the pressure is 4.0-4.5 MPa, the catalyst is Raney nickel catalyst, and the reaction time is 1.5 h-2 h.

4. The novel production process of lactitol according to claim 1, characterized in that: In the step b), the lactose hydrogenated liquid is filtered by a ceramic membrane, and the filtering pressure does not exceed 30 Bar.

5. The novel production process of lactitol according to claim 1, characterized in that: The ion exchange process in step c) is sequentially primary cation exchange, primary anion exchange, secondary cation exchange, secondary anion exchange, and mixed bed ion exchange.

6. The novel production process of lactitol according to claim 1, characterized in that: The water-to-material ratio in the chromatographic separation process in step d) is no more than 1:

3.

7. The novel production process of lactitol according to claim 1, characterized in that: The purity of lactitol in the chromatographic extract in step d) is not less than 99%.

8. The novel production process of lactitol according to claim 1, characterized in that: The concentration of the concentrated solution in step e) is not less than 90%.

9. The novel production process of lactitol according to claim 1, characterized in that: The particle size of the seed crystals added in step f) is 0.03-0.07 mm.

10. The novel production process of lactitol according to claim 1, characterized in that: The temperature of the melt granulation in step f) is controlled at 120-130°C.

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