A system and method for rapid concentration of allulose

Abstract

The present invention provides a system and method for rapid concentration of psicose, comprising the steps of: taking a psicose chromatographic extract and evaporating it in a two-stage short-path distiller to obtain a psicose concentrate. This invention abandons the traditional process of evaporating and concentrating the material in a multi-effect shell-and-tube evaporator and instead innovates the low-temperature, ultra-low vacuum method of molecular distillation for rapid concentration. This system and method not only avoids the decomposition of psicose in the evaporator caused by high temperatures but also effectively prevents an increase in the color value of the material, thereby improving the subsequent crystallization effect and crystallization recovery rate. The color value of the mother liquor after crystallization is also significantly reduced, reducing the industrial production costs caused by material discoloration due to pigment accumulation when the mother liquor is reused.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine and food, and in particular to a system and method for rapidly concentrating allulose. Background Art

[0002] A tubular evaporator is a type of natural circulation evaporator. Heating steam enters the tubes, and the heated solution circulates along the tubes in the heating chamber. Tubular evaporators primarily include central circulation tubular evaporators, spiral tube evaporators, and coil evaporators. They all operate by combining a heating chamber and a separation chamber. The heating chamber, also known as the boiling chamber, uses saturated steam to boil the material. The separation chamber, also known as the evaporation chamber, heats and vaporizes the solution in the heating chamber, producing a secondary vapor containing a large number of liquid droplets. The sudden increase in the evaporation volume in the evaporation chamber causes the droplets to condense and settle, separating them from the steam.

[0003] Currently, one production process for allulose is enzymatic production. The resulting allulose extract undergoes chromatographic separation and is then concentrated and crystallized to produce the finished product. Evaporation and concentration of the allulose extract primarily utilizes a shell-and-tube evaporator. Because the brix of the allulose extract after chromatographic separation is relatively low, only 15%-20%, some companies employ membrane concentration technology to pre-concentrate the extract to 35%. After pre-concentration, the material is then concentrated in a triple- or quadruple-effect shell-and-tube evaporator. Allulose is a heat-sensitive sugar. Generally, it decomposes and discolors when temperatures exceed 60°C during the evaporation and concentration process. Furthermore, the triple- or quadruple-effect evaporation process requires long evaporation times and different temperatures within the evaporation chamber. As the temperature changes, the color of the material increases within the evaporation chamber. Even at high temperatures in the first evaporation phase, some allulose decomposes, with decomposition reaching 2%-4%. This results in a decrease in purity after evaporation and concentration. The existing concentration and evaporation technology discharges the material when the concentration of allulose in the evaporation chamber is concentrated to a BX of 75%-85%. After discharge, the color value of the concentrated liquid increases from 5-10 IU to 50-100 IU, and the purity of allulose detected by liquid chromatography drops from greater than 98% to 95%-97%. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that in the prior art, psicose is easily decomposed due to high temperature during evaporation and concentration, and its color value increases due to a long residence time in a shell-and-tube evaporator. A new system and method for rapid concentration of psicose are provided.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0006] A rapid psicose concentration system includes a raw material tank, a first-stage short-path distiller, a pre-concentration buffer tank, a second-stage short-path distiller, and a discharge buffer tank. A psicose chromatographic extract enters the first-stage short-path distiller from the raw material tank for first-stage distillation. The resulting pre-concentrated psicose solution enters the pre-concentration buffer tank and then enters the second-stage short-path distiller for second-stage distillation to obtain a psicose concentrated solution that enters the discharge buffer tank.

[0007] Heat transfer oil pipes are provided on the raw material tank, the first-stage short-path distiller and the second-stage short-path distiller as heating sources.

[0008] The first and second short-path stills are equipped with a vacuum pump, consisting of a liquid nitrogen trap and a vacuum pump. The liquid nitrogen trap is connected to the still chamber of the short-path still via a pipe, and the vacuum pump is also connected to the liquid nitrogen trap via a pipe. The liquid nitrogen trap, also known as a liquid nitrogen cold trap, assists the vacuum pump in quickly reaching extremely low negative pressures.

[0009] A variable frequency pump is installed on the pipeline between the raw material tank and the first short-path distiller, and on the pipeline between the pre-concentration buffer tank and the second short-path distiller. The inlet and outlet volumes are adjusted by adjusting the frequency of the variable frequency pump.

[0010] The variable frequency pump is a gear variable frequency pump.

[0011] A method for rapidly concentrating psicose comprises the following steps: taking a psicose chromatographic extract and performing evaporation treatment in a two-stage short-path distiller to obtain a psicose concentrated solution.

[0012] Preferably, the heat source of the two-stage short-path distiller is thermal oil.

[0013] Preferably, the psicose chromatographic extract is heated with heat-conducting oil before entering the primary short-path distiller.

[0014] Preferably, the evaporation temperature of the thermal oil is 35°C-46°C.

[0015] Preferably, the vacuum degree of the two-stage short-path distiller is -0.095 MPa to -0.09 MPa. This vacuum degree range takes into account both the equipment cost in large-scale production and the evaporation effect of psicose.

[0016] Preferably, the temperature of the cooling water in the two-stage short-path distiller is 20°C-25°C.

[0017] Preferably, the speed of the scraper rotor motor of the two-stage short-path distiller is set to 200-350 r / min.

[0018] The above solution of the present invention includes at least the following beneficial effects:

[0019] Molecular distillation is a specialized liquid-liquid separation technique based on the differences in the mean free path of molecules of different substances. Different molecules have different mean free paths due to their varying effective molecular diameters. Light molecules have longer mean free paths, while heavy molecules have shorter ones. As a liquid mixture flows over a heating plate and is heated, light and heavy molecules escape the liquid surface and enter the gas phase. Due to the different mean free paths, light molecules travel a greater distance after escaping the liquid surface, while heavy molecules travel a shorter distance. Light molecules are able to reach the condensation plate and are condensed and discharged, while heavy molecules are unable to reach the condensation plate and are discharged along the heating plate, achieving separation. Because light molecules travel a much shorter distance to be condensed than other distillation separation methods, molecular distillation is also called short-path distillation. When molecular distillation is performed under a high vacuum, the reduced collisions between molecules make it easier for them to escape the liquid surface and reach the condensation plate, thereby improving separation efficiency. Molecular distillation technology utilizes the differences in the mean free path of molecular motion between different substances, achieving a more efficient, low-temperature separation process, especially under a high vacuum environment. It has a better separation effect on heat-sensitive substances such as allulose, achieving the goal of rapid concentration and discharge of allulose.

[0020] The psicose concentrate obtained by the present invention using molecular distillation technology has a BX of 75%-85%, a color value of 5-10 IU, and a purity greater than 98%. The psicose undergoes no decomposition and its purity remains unchanged. This improves the subsequent crystallization effect and recovery rate. Furthermore, the color value of the mother liquor after crystallization is significantly reduced, reducing industrial production costs associated with material discoloration due to pigment accumulation when the mother liquor is reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the rapid psicose concentration system of the present invention.

[0022] Among them, 1. Raw material tank; 2. Raw material tank level gauge; 3. First-stage feed frequency conversion pump; 4. First-stage feed flow meter; 5. Drain valve; 6. First-stage feed check valve; 7. First-stage liquid nitrogen trap; 8. First-stage vacuum pump; 9. First-stage short-path distiller; 10. Pre-concentration buffer tank; 11. Pre-concentration buffer tank level gauge; 12. Pre-concentration buffer tank thermometer; 13. First-stage condensate buffer tank; 14. First-stage condensate buffer tank level gauge; 15. First-stage short-path distillation frequency conversion discharge pump; 16. First-stage short-path distillation vacuum pressure gauge; 17. First-stage short-path distillation feed automatic switch valve; 18. Second-stage short-path distillation feed automatic switch valve; 19. Second-stage scraper rotor motor; 20. Second-stage short-path distillator; 21. Second-stage liquid nitrogen trap; 22. Second-stage vacuum pump; 23. Discharge buffer tank; 24. Second-stage condensate buffer tank; 25. Second-stage cold Condensate variable frequency pump; 26. Secondary discharge variable frequency pump; 27. Primary condensate variable frequency pump; 28. Condensate storage tank; 29. ​​Concentration tank; 30. Secondary short-path distillation vacuum pressure gauge; 31. Primary short-path scraper; 32. Secondary short-path scraper; 33. Primary scraper rotor motor; 34. Primary short-path distillation thermal oil digital thermometer; 35. Secondary short-path distillation thermal oil digital thermometer; 36. Primary short-path distillation cooling water inlet switch valve; 37. Primary short-path distillation cooling water return regulating valve; 38. Secondary short-path distillation cooling water inlet switch valve; 39. Secondary short-path distillation cooling water return regulating valve; 40. Primary cooling water return digital thermometer; 41. Secondary cooling water return digital thermometer; 42. Secondary feed flowmeter; 43. Discharge buffer tank level gauge; 44. Secondary feed check valve; 45. Secondary condensate buffer tank level gauge. DETAILED DESCRIPTION

[0023] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] A rapid allulose concentration system, such as Figure 1 As shown, it mainly includes a raw material tank 1, a primary short-path distiller 9, a pre-concentration buffer tank 10, a secondary short-path distiller 20 and a discharge buffer tank 23. The psicose chromatographic extract enters the primary short-path distiller 9 from the raw material tank 1 for primary distillation. The obtained pre-concentrated psicose solution enters the pre-concentration buffer tank 10 and then enters the secondary short-path distiller 20 for secondary distillation. The obtained psicose concentrated solution enters the discharge buffer tank 23.

[0025] The raw material tank 1, the first-stage short-path distiller 9 and the second-stage short-path distiller 20 are all provided with heat-conducting oil pipes as heating sources.

[0026] A vacuum pump is provided on the primary short-path distiller 9 and the secondary short-path distiller 20. The vacuum pump comprises a liquid nitrogen trap and a vacuum pump. The liquid nitrogen trap is connected to the distillation chamber of the short-path distiller through a pipeline, and the vacuum pump is connected to the liquid nitrogen trap through a pipeline.

[0027] Variable frequency pumps are installed on the pipelines between the raw material tank 1 and the first short-path still 9, and between the pre-concentration buffer tank 10 and the second short-path still 20. The feed and discharge rates are regulated by adjusting the frequency of the variable frequency pumps. The variable frequency pumps are gear variable frequency pumps.

[0028] The first-stage feed variable frequency pump 3, the first-stage short-path distillation variable frequency discharge pump 15, the first-stage condensate variable frequency pump 27, the second-stage condensate variable frequency pump 25, and the second-stage discharge variable frequency pump 26 are all gear variable frequency pumps.

[0029] The primary feed one-way valve 6 and the secondary feed one-way valve 44 ensure that the material flows in one direction. Example 1

[0030] By using the above system, allulose is quickly concentrated, including the following steps: taking a chromatographic extract of allulose with a brix of 15%-20%, evaporating it in a two-stage short-path distiller to obtain a allulose concentrate.

[0031] The specific steps of evaporating the allulose chromatographic extract in a two-stage short-path distiller are as follows:

[0032] Step 1: The thermal oil station starts to supply thermal oil to the raw material tank 1, the first-stage short-path distiller 9, and the second-stage short-path distiller 20. The thermal oil temperature is set to 35°C. Observe the first-stage short-path distillation thermal oil digital thermometer 34 and the second-stage short-path distillation thermal oil digital thermometer 35 to keep the digital temperature constant without large fluctuations. Open the first-stage short-path distillation cooling water inlet switch valve 36, adjust the opening size of the first-stage short-path distillation cooling water return regulating valve 37, open the second-stage short-path distillation cooling water inlet switch valve 38, adjust the opening size of the second-stage short-path distillation cooling water return regulating valve 39, observe the first-stage cooling water return digital thermometer 40 and the second-stage cooling water return digital thermometer 41, and control the temperature at 20°C-25°C without large fluctuations.

[0033] Step 2: Transport the allulose raw material to the raw material tank 1, observe the raw material tank level gauge 2, and maintain the raw material in the raw material tank to 50% of the tank level.

[0034] Step 3: Add liquid nitrogen into the first-level liquid nitrogen trap 7 and the second-level liquid nitrogen trap 21, turn on the first-level vacuum pump 8 and the second-level vacuum pump 22, observe the first-level short-path distillation vacuum pressure gauge 16 and the second-level short-path distillation vacuum pressure gauge 30, and control the vacuum degree to be stable at -0.095 MPa.

[0035] Step 4: Open the first-stage feed one-way valve 6, the first-stage short-path distillation feed automatic switch valve 17, and the first-stage feed variable frequency pump 3. After the material enters the first-stage short-path distiller 9, turn on the first-stage scraper rotor motor 33, and set the speed to 200-350r / min to drive the first-stage short-path scraper 31 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the first-stage short-path distiller 9. As the scraper rotates, the material also begins to distill; at the same time, observe the first-stage feed flowmeter 4 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the first-stage feed variable frequency pump 3.

[0036] Step 5: The material begins to evaporate after entering the first-stage short-path distiller 9. Observe the level gauge 14 of the first-stage condensate buffer tank. After the condensate enters the first-stage condensate buffer tank 13, start the first-stage condensate variable frequency pump 27; the condensate enters the condensate storage tank 28.

[0037] Step 6: Observe the pre-concentration buffer tank level gauge 11 and the pre-concentration buffer tank thermometer 12. After the pre-concentrated material enters the pre-concentration buffer tank 10, open the secondary feed one-way valve 44 and the secondary short-path distillation feed automatic switch valve 18, and open the primary short-path distillation variable frequency discharge pump 15. When the material enters the secondary short-path distiller 20, turn on the secondary scraper rotor motor 19, and set the speed to 200-350r / min to drive the secondary short-path scraper 32 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the secondary short-path distiller 20. As the scraper rotates, the material undergoes final evaporation and concentration. Observe the secondary feed flowmeter 42 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the primary short-path distillation variable frequency discharge pump 15.

[0038] Step 7: The material begins to evaporate after entering the secondary short-path distiller. Observe the liquid level gauge 45 of the secondary condensate buffer tank. After the condensate enters the secondary condensate buffer tank 24, start the secondary condensate variable frequency pump 25; the condensate enters the condensate storage tank 28.

[0039] Step 8: Observe the level gauge 43 of the discharge buffer tank. After the material enters the discharge buffer tank 23, start the secondary discharge variable frequency pump 26, and the material enters the concentration tank 29 through the pipeline. The obtained concentrate has a Brix of 75%-85%.

[0040] Step 9: When shutting down, the shutdown sequence is to shut down the first-level vacuum pump 8, the second-level vacuum pump 22, the first-level scraper rotor motor 33, the second-level scraper rotor motor 19, shut down all thermal oil inlets and outlets, shut down all variable frequency pumps, and after the temperature drops to room temperature, close all cooling water inlet and return valves, and open the drain valve 5 to discharge the residual material in the pipeline.

[0041] After the system is stabilized, the time from feeding to discharging is determined, and the color value and purity changes of allulose are detected. Example 2

[0042] By using the above system, allulose is quickly concentrated, including the following steps: taking a chromatographic extract of allulose with a brix of 15%-20%, evaporating it in a two-stage short-path distiller to obtain a allulose concentrate.

[0043] The specific steps of evaporating the allulose chromatographic extract in a two-stage short-path distiller are as follows:

[0044] Step 1: The thermal oil station starts to supply thermal oil to the raw material tank 1, the first-stage short-path distiller 9, and the second-stage short-path distiller 20. The thermal oil temperature is set to 46°C. Observe the first-stage short-path distillation thermal oil digital thermometer 34 and the second-stage short-path distillation thermal oil digital thermometer 35 to keep the digital temperature constant without large fluctuations. Open the first-stage short-path distillation cooling water inlet switch valve 36, adjust the opening size of the first-stage short-path distillation cooling water return regulating valve 37, open the second-stage short-path distillation cooling water inlet switch valve 38, adjust the opening size of the second-stage short-path distillation cooling water return regulating valve 39, observe the first-stage cooling water return digital thermometer 40 and the second-stage cooling water return digital thermometer 41, and control the temperature at 20°C-25°C without large fluctuations.

[0045] Step 2: Transport the allulose raw material to raw material tank 1, observe the raw material tank level gauge 2, and maintain the raw material in raw material tank 1 to 50% of the tank level.

[0046] Step 3: Add liquid nitrogen into the first-level liquid nitrogen trap 7 and the second-level liquid nitrogen trap 21, turn on the first-level vacuum pump 8 and the second-level vacuum pump 22, observe the first-level short-path distillation vacuum pressure gauge 16 and the second-level short-path distillation vacuum pressure gauge 30, and control the vacuum degree to be stable at -0.09 MPa.

[0047] Step 4: Open the first-stage feed one-way valve 6, the first-stage short-path distillation feed automatic switch valve 17, and the first-stage feed variable frequency pump 3. After the material enters the first-stage short-path distiller 9, turn on the first-stage scraper rotor motor 33, and set the speed to 200-350r / min to drive the first-stage short-path scraper 31 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the first-stage short-path distiller 9. As the scraper rotates, the material also begins to distill; at the same time, observe the first-stage feed flowmeter 4 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the first-stage feed variable frequency pump 3.

[0048] Step 5: The material begins to evaporate after entering the first-stage short-path distiller 9. Observe the level gauge 14 of the first-stage condensate buffer tank. After the condensate enters the first-stage condensate buffer tank 13, start the first-stage condensate variable frequency pump 27; the condensate enters the condensate storage tank 28.

[0049] Step 6: Observe the pre-concentration buffer tank level gauge 11 and the pre-concentration buffer tank thermometer 12. After the pre-concentrated material enters the pre-concentration buffer tank 10, open the secondary feed one-way valve 44 and the secondary short-path distillation feed automatic switch valve 18, and open the primary short-path distillation variable frequency discharge pump 15. When the material enters the secondary short-path distiller 20, turn on the secondary scraper rotor motor 19, and set the speed to 200-350r / min to drive the secondary short-path scraper 32 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the secondary short-path distiller 20. As the scraper rotates, the material undergoes final evaporation and concentration. Observe the secondary feed flowmeter 42 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the primary short-path distillation variable frequency discharge pump 15.

[0050] Step 7: The material begins to evaporate after entering the secondary short-path distiller. Observe the liquid level gauge 45 of the secondary condensate buffer tank. After the condensate enters the secondary condensate buffer tank 24, start the secondary condensate variable frequency pump 25; the condensate enters the condensate storage tank 28.

[0051] Step 8: Observe the level gauge 43 of the discharge buffer tank. After the material enters the discharge buffer tank 23, start the secondary discharge variable frequency pump 26, and the material enters the concentration tank 29 through the pipeline. The obtained concentrate has a Brix of 75%-85%.

[0052] Step 9: When shutting down, the shutdown sequence is to shut down the first-level vacuum pump 8, the second-level vacuum pump 22, the first-level scraper rotor motor 33, the second-level scraper rotor motor 19, shut down all thermal oil inlets and outlets, shut down all variable frequency pumps, and after the temperature drops to room temperature, close all cooling water inlet and return valves, and open the drain valve 5 to discharge the residual material in the pipeline.

[0053] After the system is stabilized, the time from feeding to discharging is determined, and the color value and purity changes of allulose are detected. Example 3

[0054] By using the above system, allulose is quickly concentrated, including the following steps: taking a chromatographic extract of allulose with a brix of 15%-20%, evaporating it in a two-stage short-path distiller to obtain a allulose concentrate.

[0055] The specific steps of evaporating the allulose chromatographic extract in a two-stage short-path distiller are as follows:

[0056] Step 1: The thermal oil station starts to supply thermal oil to the raw material tank 1, the first-stage short-path distiller 9, and the second-stage short-path distiller 20. The thermal oil temperature is set to 40°C. Observe the first-stage short-path distillation thermal oil digital thermometer 34 and the second-stage short-path distillation thermal oil digital thermometer 35 to keep the digital temperature constant without large fluctuations. Open the first-stage short-path distillation cooling water inlet switch valve 36, adjust the opening size of the first-stage short-path distillation cooling water return regulating valve 37, open the second-stage short-path distillation cooling water inlet switch valve 38, adjust the opening size of the second-stage short-path distillation cooling water return regulating valve 39, observe the first-stage cooling water return digital thermometer 40 and the second-stage cooling water return digital thermometer 41, and control the temperature at 20°C-25°C without large fluctuations.

[0057] Step 2: Transport the allulose raw material to raw material tank 1, observe the raw material tank level gauge 2, and maintain the raw material in raw material tank 1 to 50% of the tank level.

[0058] Step 3: Add liquid nitrogen into the first-level liquid nitrogen trap 7 and the second-level liquid nitrogen trap 21, turn on the first-level vacuum pump 8 and the second-level vacuum pump 22, observe the first-level short-path distillation vacuum pressure gauge 16 and the second-level short-path distillation vacuum pressure gauge 30, and control the vacuum degree to be stable at -0.093 MPa.

[0059] Step 4: Open the first-stage feed one-way valve 6, the first-stage short-path distillation feed automatic switch valve 17, and the first-stage feed variable frequency pump 3. After the material enters the first-stage short-path distiller 9, turn on the first-stage scraper rotor motor 33, and set the speed to 200-350r / min to drive the first-stage short-path scraper 31 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the first-stage short-path distiller 9. As the scraper rotates, the material also begins to distill; at the same time, observe the first-stage feed flowmeter 4 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the first-stage feed variable frequency pump 3.

[0060] Step 5: The material begins to evaporate after entering the first-stage short-path distiller 9. Observe the level gauge 14 of the first-stage condensate buffer tank. After the condensate enters the first-stage condensate buffer tank 13, start the first-stage condensate variable frequency pump 27; the condensate enters the condensate storage tank 28.

[0061] Step 6: Observe the pre-concentration buffer tank level gauge 11 and the pre-concentration buffer tank thermometer 12. After the pre-concentrated material enters the pre-concentration buffer tank 10, open the secondary feed one-way valve 44 and the secondary short-path distillation feed automatic switch valve 18, and open the primary short-path distillation variable frequency discharge pump 15. When the material enters the secondary short-path distiller 20, turn on the secondary scraper rotor motor 19, and set the speed to 200-350r / min to drive the secondary short-path scraper 32 to rotate in the distillation chamber, and evenly spread the material on the inner wall of the secondary short-path distiller 20. As the scraper rotates, the material undergoes final evaporation and concentration. Observe the secondary feed flowmeter 42 to control the feed amount to be constant. The feed amount can be adjusted by adjusting the frequency of the primary short-path distillation variable frequency discharge pump 15.

[0062] Step 7: The material begins to evaporate after entering the secondary short-path distiller. Observe the liquid level gauge 45 of the secondary condensate buffer tank. After the condensate enters the secondary condensate buffer tank 24, start the secondary condensate variable frequency pump 25; the condensate enters the condensate storage tank 28.

[0063] Step 8: Observe the level gauge 43 of the discharge buffer tank. After the material enters the discharge buffer tank 23, start the secondary discharge variable frequency pump 26, and the material enters the concentration tank 29 through the pipeline. The obtained concentrate has a Brix of 75%-85%.

[0064] Step 9: When shutting down, the shutdown sequence is to shut down the first-level vacuum pump 8, the second-level vacuum pump 22, the first-level scraper rotor motor 33, the second-level scraper rotor motor 19, shut down all thermal oil inlets and outlets, shut down all variable frequency pumps, and after the temperature drops to room temperature, close all cooling water inlet and return valves, and open the drain valve 5 to discharge the residual material in the pipeline.

[0065] After the system is stabilized, the time from feeding to discharging is determined, and the color value and purity changes of allulose are detected.

[0066] It should be noted that the above steps can be controlled by the DCS control system, and the DCS PID can be used to adjust the liquid level of each storage tank, the temperature and pressure in the system, the inlet and outlet flow, and the start and stop of each power pump. Comparative Example 1

[0067] The existing three-effect shell-and-tube evaporator is used as an example for the evaporation and concentration of allulose. The raw material has a Brix of 15%-20%, the first-effect evaporation chamber temperature is 70°C-75°C, the second-effect evaporation chamber temperature is 65°C-70°C, and the third-effect evaporation chamber temperature is 60°C-65°C. After evaporation and concentration to a Brix of 75%-85%, the material is discharged from the second-effect evaporator. After the system stabilizes, the time from feed to discharge is determined, and the color value and purity of the allulose are tested. Comparative Example 2

[0068] Lower the evaporation temperature, increase the number of effects, and expand the allulose evaporation and concentration process to a four-effect evaporation process. Set the raw material's Brix to 15%-20%, set the first-effect evaporation chamber temperature to 65°C-70°C, the second-effect evaporation chamber temperature to 60°C-65°C, the third-effect evaporation chamber temperature to 55°C-60°C, and the fourth-effect evaporator temperature to 50°C-55°C. After evaporation and concentration to a Brix of 75%-85%, discharge from the third-effect evaporator. Once the system stabilizes, determine the time from feed to discharge, and test the allulose color and purity.

[0069] The test results of Examples 1-3 and Comparative Examples 1 and 2 are compared in the following table:

[0070]

[0071] As can be seen from the above table, by using the molecular distillation technology of the present invention, the color value of the concentrated psicose chromatographic extract does not increase, the purity is basically maintained, and the discharge time is greatly shortened.

[0072] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. A system for rapid concentration of psicose, characterized in that: The method comprises a raw material tank, a first-stage short-path distiller, a pre-concentration buffer tank, a second-stage short-path distiller and a discharge buffer tank. The psicose chromatographic extract enters the first-stage short-path distiller from the raw material tank for first-stage distillation. The obtained pre-concentrated psicose solution enters the pre-concentration buffer tank and then enters the second-stage short-path distiller for second-stage distillation to obtain a psicose concentrated solution which enters the discharge buffer tank. A vacuum device is provided on the first-stage short-path distiller and the second-stage short-path distiller. The vacuum device comprises a liquid nitrogen trap and a vacuum pump. The liquid nitrogen trap is connected to the distillation chamber of the short-path distiller through a pipeline, and the vacuum pump is connected to the liquid nitrogen trap through a pipeline.

2. The system for rapid concentration of psicose according to claim 1, wherein: Heat transfer oil pipes are provided on the raw material tank, the first-stage short-path distiller and the second-stage short-path distiller as heating sources.

3. A method for rapid concentration of psicose, characterized in that: The method comprises the following steps: taking a chromatographic extract of psicose and performing evaporation treatment in a two-stage short-path distiller to obtain a psicose concentrate, wherein the heat source of the two-stage short-path distiller is thermal oil, and the vacuum degree of the two-stage short-path distiller is -0.095 MPa to -0.09 MPa.

4. The method for rapid concentration of psicose according to claim 3, wherein: The allulose chromatographic extract was heated with heat-conducting oil before entering the primary short-path distiller.

5. The method for rapid concentration of psicose according to claim 3, wherein: The evaporation temperature of the thermal oil is 35℃-46℃.

6. The method for rapid concentration of psicose according to claim 3, wherein: The temperature of the cooling water in the two-stage short-path distiller is 20°C-25°C.

7. The method for rapid concentration of psicose according to claim 3, wherein: The scraper rotor motor speed of the two-stage short-path distiller is set to 200-350r / min.

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