System and method for coproduction of l-arabinose and caramel color from xylose chromatography raffinate

Abstract

The present application belongs to the technical field of sugar alcohol preparation, and relates to a system and a method for co-production of L-arabinose and caramel colorant by using xylose chromatography raffinate, which comprises a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation and concentration tank, a crystallization tank, a centrifugal separator and a dryer which are sequentially connected by pipelines, and a browning reaction assembly for mixing the raffinate and the centrifugal mother liquor and then performing browning reaction treatment to prepare caramel colorant. The chromatographic separation device is used for separating the nanofiltration permeate flowing therethrough into extract and raffinate, the evaporation and concentration tank and the crystallization tank are used for concentrating and crystallizing the extract flowing therethrough into sugar paste, the centrifugal separator is used for separating the sugar paste flowing therethrough into moist sugar and centrifugal mother liquor, and the dryer is used for drying the moist sugar flowing therethrough into L-arabinose crystals. The present application mixes the raffinate and the centrifugal mother liquor to prepare caramel colorant liquid product, thereby improving the utilization rate of sugar resources and obtaining caramel colorant additional product.

Description

Technical Field

[0001] This invention belongs to the field of sugar alcohol preparation technology, and specifically relates to a system and method for co-producing L-arabinose and caramel color using xylose chromatographic residue. Background Technology

[0002] In the process of preparing xylose from corn cobs, a large amount of xylose mother liquor is obtained during the centrifugation process. This mother liquor can be further processed by chromatography to extract xylose. During this chromatographic separation, a residue is also obtained, which is the xylose chromatographic separation residue. The xylose chromatographic separation residue contains approximately 30 wt% arabinose, 30 wt% glucose, 10 wt% xylose, 15 wt% galactose, and a small amount of mannose, among other sugars. Due to variations in production conditions and batches, the content of these sugars fluctuates, making their efficient utilization difficult. Currently, most xylose chromatographic separation residue is sold externally for use as a mixed syrup, resulting in low added value.

[0003] L-arabinose, also known as gum aldehyde or pectin sugar, is a pentanalose with the chemical formula C5H. 10 O5. The preparation of L-arabinose dates back to the early 20th century, when it was mainly isolated from some plant gums. With the development of technology, the technology of recovering arabinose from sugar by-products (xylose mother liquor, chromatographic separation liquid, etc.) has gradually become mainstream. However, the production of L-arabinose generates a large amount of solid waste, and subsequent chromatographic residues and centrifugal mother liquors are difficult to utilize effectively.

[0004] Caramel color is a dark brown mixture produced by the high-temperature reaction of sugars, widely used in foods such as soy sauce and vinegar. When used in dark soy sauce or braising sauce, a high red index is required for the caramel color, generally greater than 6.3 (at a color index of 20000 EBC). Therefore, the preparation of this type of high red index caramel color usually requires the use of hexoses with longer carbon chains. Xylose chromatographic residues, apart from arabinose and a small amount of xylose, are primarily hexoses, making it a potential candidate for preparing high red index caramel color. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a system and method for co-producing L-arabinose and caramel color using xylose chromatography retrieval liquid. The retrieval liquid and centrifugation mother liquor are mixed to prepare a caramel color liquid product, which improves the utilization rate of sugar resources and also obtains caramel color by-product, thereby improving the comprehensive utilization value of xylose chromatography retrieval liquid.

[0006] This invention provides a system for co-producing L-arabinose and caramel color using xylose chromatographic residue. The system comprises a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation and concentration tank, a crystallization tank, a centrifuge, and a dryer, all connected sequentially by pipelines. The raw material tank stores the xylose chromatographic residue. The nanofiltration membrane separator decolorizes the xylose chromatographic residue into a nanofiltration cut-off liquid and a nanofiltration permeate. The chromatographic separation device separates the nanofiltration permeate into an extract with a high arabinose content and a residue with a low arabinose content. The evaporation and concentration tank and the crystallization tank concentrate and crystallize the extract into a sugar paste. The centrifuge separates the sugar paste into humid sugar and a centrifugal mother liquor. The dryer dries the humid sugar into L-arabinose crystals. The system also includes a browning reaction component for mixing the residue and the centrifugal mother liquor and then performing a browning reaction to prepare caramel color.

[0007] Furthermore, the browning reaction assembly includes an enzyme catalytic tank, a browning reaction vessel, a flash evaporator, an ultrafiltration membrane separator, and a scraped membrane evaporator. The enzyme catalytic tank is used to mix the raffinate with the centrifuged mother liquor and then add enzyme preparations for enzyme catalysis to produce a ketose solution. The browning reaction vessel is used to brown the flowing ketose solution to produce crude caramel color. The flash evaporator is used to remove amino compounds or sulfite impurities from the flowing crude caramel color. The ultrafiltration membrane separator is used to remove 4-methylimidazole impurities from the flowing crude caramel color. The scraped membrane evaporator is used to concentrate the flowing crude caramel color at low temperature to produce a high red finger caramel color liquid product.

[0008] Furthermore, the enzyme preparation is a glucose isomerase.

[0009] This invention is implemented as follows, and also provides a method for co-producing L-arabinose and caramel color using xylose chromatographic residue, characterized in that it uses the system for co-producing L-arabinose and caramel color using xylose chromatographic residue as described above, and the method includes the following steps:

[0010] Step 1: The xylose chromatography residue in the raw material tank is transferred to a nanofiltration membrane separator through a pipeline for decolorization. After decolorization, nanofiltration retentate and nanofiltration permeate are obtained, wherein the transmittance of the nanofiltration permeate is >95%.

[0011] Step 2: The nanofiltration permeate is transported through a pipeline to a chromatographic separation device for separation. After separation, an extract and a residue are obtained. The extract is then subjected to evaporation and concentration, crystallization, and centrifugation to obtain hygroscopic sugar and a centrifuged mother liquor with a refractive index >70%.

[0012] Step 3: After the molasses is transported to a dryer for drying, L-arabinose crystals with the required purity >99% are obtained;

[0013] Step 4: The centrifuged mother liquor and the residue are separately sent to an enzyme catalytic tank for mixing. Enzyme preparation is added to the enzyme catalytic tank for enzyme catalytic treatment to obtain ketose solution. The ketose solution is then subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped membrane evaporation treatment in sequence to obtain the desired high red finger caramel color liquid product.

[0014] Compared with the prior art, the system and method of the present invention for co-producing L-arabinose and caramel color using xylose chromatographic residue has the following characteristics:

[0015] 1. Existing processes use activated carbon for decolorization, which is costly and pollutes the environment. In contrast, this invention uses nanofiltration membrane separation to decolorize the xylose chromatographic residue, which avoids the generation of solid waste and dust and reduces production costs.

[0016] 2. The residue and centrifugation mother liquor from the L-arabinose extraction process are used to prepare a high red index caramel color liquid product with a red index as high as 6.3 (at a color rate of 20,000 EBC). The comprehensive utilization rate of sugar resources can reach over 92%. The xylose chromatography residue, which sells for 1,500 yuan / ton, is transformed into L-arabinose crystals worth 40,000 yuan / ton and high red index caramel color liquid product worth 3,000 yuan / ton, increasing economic benefits by 3 to 5 times and avoiding the low-value utilization of sugar resources. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the principle of the system for co-producing L-arabinose and caramel color using xylose chromatographic residue of the present invention.

[0018] Figure 2 This is a schematic diagram illustrating the process principle of a method for co-producing L-arabinose and caramel color using xylose chromatographic residue. Detailed Implementation

[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0020] Please refer to Figure 1 As shown, a preferred embodiment of the system for co-producing L-arabinose and caramel color using xylose chromatographic residue of the present invention includes a raw material tank 1, a nanofiltration membrane separator 2, a chromatographic separation device 3, an evaporation and concentration tank 4, a crystallization tank 5, a centrifuge 6, and a dryer 7, which are connected in sequence by pipelines.

[0021] Raw material tank 1 is used to store xylose chromatography residue A. Nanofiltration membrane separator 2 is used to decolorize the xylose chromatography residue A into nanofiltration retentate B and nanofiltration permeate C. Chromatographic separation device 3 is used to separate the nanofiltration permeate C into extract D with high arabinose content and residue E with low arabinose content. Evaporation and concentration tank 4 and crystallization tank 5 are used to concentrate and crystallize the extract D into sugar paste. Centrifuge 6 is used to separate the sugar paste into humid sugar and centrifugal mother liquor F. Dryer 7 is used to dry the humid sugar into L-arabinose crystals G.

[0022] The system also includes a browning reaction assembly for mixing the raffinate E with the centrifuged mother liquor F and then performing a browning reaction to prepare caramel color. The browning reaction assembly includes an enzyme catalytic vessel 8, a browning reaction vessel 9, a flash evaporator 10, an ultrafiltration membrane separator 11, and a scraped membrane evaporator 12.

[0023] Enzyme catalysis tank 8 is used to mix the raffinate E with the centrifuged mother liquor F and then add enzyme preparations for enzyme catalysis to produce ketose solution. Browning reaction vessel 9 is used to brown the flowing ketose solution to produce crude caramel color. Flash evaporator 10 is used to remove amino compounds or sulfite impurities from the flowing crude caramel color. Ultrafiltration membrane separator 11 is used to remove 4-methylimidazole impurities from the flowing crude caramel color. Scraped membrane evaporator 12 is used to concentrate the flowing crude caramel color at low temperature to produce high red finger caramel color liquid product H.

[0024] The enzyme preparation is a glucose isomerase.

[0025] Please refer to the following at the same time Figure 1 and Figure 2 As shown, the present invention also discloses a method for co-producing L-arabinose and caramel color using xylose chromatographic residue, which uses the system for co-producing L-arabinose and caramel color using xylose chromatographic residue as described above, and the method includes the following steps:

[0026] Step 1: The xylose chromatography residue A in raw material tank 1 is transported to nanofiltration membrane separator 2 through pipeline for decolorization treatment. After decolorization treatment, nanofiltration retentate B and nanofiltration permeate C are obtained, wherein the transmittance of nanofiltration permeate C is >95%.

[0027] Step 2: The nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment. After separation treatment, extract D and raffinate E are obtained. Extract D is then subjected to evaporation concentration treatment, crystallization treatment and centrifugation separation treatment in sequence to obtain hygroscopic sugar and centrifugation mother liquor F with refractive index >70%.

[0028] Step 3: After the molasses is transported to dryer 7 for drying, L-arabinose crystals G with the required purity >99% are obtained.

[0029] Step 4: The centrifuged mother liquor F and the raffinate E are respectively sent to enzyme catalysis tank 8 for mixing. Enzyme preparation is added to enzyme catalysis tank 8 to obtain ketose solution. The ketose solution is then subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped membrane evaporation treatment to obtain the desired high red finger caramel color liquid product H.

[0030] In step one, the xylose chromatographic residue A has a dry matter percentage concentration (i.e., sugar concentration) of 70-80 wt%, a transmittance of 20-40%, and a conductivity of 5-10 μS / cm. Specifically, the dry matter contains 28-30 wt% arabinose, 26-33 wt% glucose, 5-10 wt% xylose, 4-6 wt% mannose, and 14-16 wt% galactose. During nanofiltration decolorization, the nanofiltration membrane separator 2 operates at a temperature of 40-60°C and a pressure of 25-35 bar. More than 90 wt% of the sugars permeate through the nanofiltration membrane, while less than 10 wt% remain in the nanofiltration retentate B.

[0031] In step two, during the separation process, commercially available resin is used, water is used as the eluent, the separation temperature is 50-70°C, and the feed contains 50-60 wt% refractive index, 27-33 wt% arabinose, 25-30 wt% glucose, and 10-16 wt% galactose. In the separated extract D, the arabinose content is >85 wt%, and the arabinose yield is >90 wt%; in the raffinate E, the arabinose content is <5 wt%, and the glucose content is >40 wt%.

[0032] In step four, during the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, with an enzyme addition amount of 1-5% of the mixed solution mass ratio. The reaction pH is 6-7, the reaction temperature is 60-70℃, and the reaction time is 100-150 min. During the browning reaction, the reaction aids used are ammonia, ammonium carbonate, or a mixture of ammonium bicarbonate and ammonium sulfite or sodium metabisulfite, with a mixing ratio of 1:4:5 to 1:2:7. The reaction process is controlled as follows: first, adjust the pH to 6.0-7.0, then raise the temperature to 85-95℃ for 30-50 min, then raise the temperature to 130-150℃ for 2-4 h, then raise the temperature to 150-170℃ for 1-2 h, and finally cool to room temperature. During the ultrafiltration membrane separation treatment, the ultrafiltration membrane separator 11 operates at a temperature of 40-60℃ and a pressure of 5-7 bar. During the scraped film evaporation process, the evaporation pressure of the scraped film evaporator 12 is 4~5 bar, and the vacuum degree is 80~90 kPa.

[0033] The following specific embodiments further illustrate the method of the present invention for co-producing L-arabinose and caramel color using xylose chromatographic residue.

[0034] Example 1

[0035] Please refer to the following at the same time: Figure 1 and Figure 2 As shown, the first embodiment of the method for co-producing L-arabinose and caramel color using xylose chromatographic residue of the present invention includes the following steps:

[0036] Step 11: The xylose chromatography residue A in raw material tank 1 is transferred to nanofiltration membrane separator 2 through pipeline for decolorization. After decolorization, nanofiltration retentate B and nanofiltration permeate C are obtained, wherein the transmittance of nanofiltration permeate C is >95%. The dry matter percentage concentration (sugar concentration) of xylose chromatography residue A is 70wt%, the transmittance is 30%, and the conductivity is 5μs / cm. In the dry matter, arabinose contains 30wt%, glucose contains 26wt%, xylose contains 8wt%, mannose contains 4wt%, and galactose contains 15wt%. During nanofiltration decolorization, the operating temperature of nanofiltration membrane separator 2 is 50℃, the operating pressure is 30bar, 92wt% of the sugar resources permeate through the nanofiltration membrane, and 8wt% of the sugar resources remain in nanofiltration retentate B.

[0037] Step 12: The nanofiltration permeate C is piped to the chromatographic separation device 3 for separation. After separation, extract D and raffinate E are obtained. Extract D is then subjected to evaporation concentration, crystallization, and centrifugation to obtain hygroscopic sugar and centrifuged mother liquor F with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 60°C, and the feed contained 55 wt% refractive index, 31 wt% arabinose, 27 wt% glucose, and 16 wt% galactose. In extract D, the arabinose content was 87 wt%, with an arabinose yield >90 wt%. In raffinate E, the arabinose content was 4 wt% and the glucose content was 43 wt%.

[0038] Step 13: After the molasses is fed to dryer 7 for drying, L-arabinose crystals G with the required purity of 99.2% are obtained.

[0039] Step 14: The centrifuged mother liquor F and the residue E are respectively sent to enzyme catalysis tank 8 for mixing. Enzyme preparation is added to enzyme catalysis tank 8 to obtain ketose solution. The ketose solution is then subjected to browning reaction, flash evaporation, ultrafiltration membrane separation, and scraped membrane evaporation to obtain the desired high red finger caramel color liquid product H. During enzyme catalysis, the enzyme preparation used is glucose isomerase, with an enzyme addition amount of 3% of the mixed solution mass ratio. The reaction pH is 6.5, the reaction temperature is 65℃, and the reaction time is 130 min. During the browning reaction, the reaction aid used is a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:3:6. The reaction process is controlled as follows: first, adjust the pH to 6.5, then raise the temperature to 90℃ for 40 min, then raise the temperature to 140℃ for 3 h, then raise the temperature to 160℃ for 1.5 h, and finally cool to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator 11 operates at a temperature of 50°C and a pressure of 6 bar; during wiped membrane evaporation, the wiped membrane evaporator 12 operates at a pressure of 4.5 bar and a vacuum of 85 kPa.

[0040] Example 2

[0041] Please refer to the following at the same time: Figure 1 and Figure 2 As shown, this is a second embodiment of the method for co-producing L-arabinose and caramel color using xylose chromatographic residue of the present invention, the method comprising the following steps:

[0042] Step 21: The xylose chromatography residue A in raw material tank 1 is transferred to nanofiltration membrane separator 2 through pipeline for decolorization. After decolorization, nanofiltration retentate B and nanofiltration permeate C are obtained, wherein the transmittance of nanofiltration permeate C is >95%. The dry matter percentage concentration (sugar concentration) of xylose chromatography residue A is 80wt%, the transmittance is 40%, and the conductivity is 10μs / cm. In the dry matter, it contains 28wt% arabinose, 33wt% glucose, 5wt% xylose, 6wt% mannose, and 14wt% galactose. During nanofiltration decolorization, the operating temperature of nanofiltration membrane separator 2 is 40℃, the operating pressure is 25bar, 90wt% of the sugar resources permeate through the nanofiltration membrane, and 10wt% of the sugar resources remain in nanofiltration retentate B.

[0043] Step 22: The nanofiltration permeate C is piped to the chromatographic separation device 3 for separation. After separation, extract D and raffinate E are obtained. Extract D is then subjected to evaporation concentration, crystallization, and centrifugation to obtain hygroscopic sugar and centrifuged mother liquor F with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 50°C, and the feed composition was 50 wt% refractive index, 27 wt% arabinose, 30 wt% glucose, and 10 wt% galactose. In extract D, the arabinose content was 86 wt%, with an arabinose yield >90 wt%. In raffinate E, the arabinose content was 5 wt% and the glucose content was 45 wt%.

[0044] Step 23: After the molasses is transported to the dryer 7 for drying, L-arabinose crystals G with the required purity of 99.2% are obtained.

[0045] Step 24: The centrifuged mother liquor F and the residue E are respectively sent to enzyme catalysis tank 8 for mixing. Enzyme preparation is added to enzyme catalysis tank 8 to obtain ketose solution. The ketose solution is then subjected to browning reaction, flash evaporation, ultrafiltration membrane separation, and scraped membrane evaporation to obtain the desired high red finger caramel color liquid product H. During enzyme catalysis, the enzyme preparation used is glucose isomerase, with an enzyme addition amount of 1% of the mixed solution mass ratio. The reaction pH is 6, the reaction temperature is 60℃, and the reaction time is 150 min. During the browning reaction, the reaction aid used is a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:4:5. The reaction process is controlled as follows: first, adjust the pH to 6.0, then raise the temperature to 85℃ for 50 min, then raise the temperature to 130℃ for 4 h, then raise the temperature to 150℃ for 2 h, and finally cool to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator 11 operates at a temperature of 60°C and a pressure of 5 bar; during wiped membrane evaporation, the wiped membrane evaporator 12 operates at a pressure of 5 bar and a vacuum of 80 kPa.

[0046] Example 3

[0047] Please refer to the following at the same time: Figure 1 and Figure 2 As shown, this is the third embodiment of the method for co-producing L-arabinose and caramel color using xylose chromatographic residue of the present invention, the method comprising the following steps:

[0048] Step 31: The xylose chromatography residue A in raw material tank 1 is transferred to nanofiltration membrane separator 2 through pipeline for decolorization. After decolorization, nanofiltration retentate B and nanofiltration permeate C are obtained, wherein the transmittance of nanofiltration permeate C is >95%. The dry matter percentage concentration (sugar concentration) of xylose chromatography residue A is 70wt%, the transmittance is 20%, and the conductivity is 5μs / cm. In the dry matter, arabinose contains 30wt%, glucose contains 33wt%, xylose contains 10wt%, mannose contains 4wt%, and galactose contains 16wt%. During nanofiltration decolorization, the operating temperature of nanofiltration membrane separator 2 is 60℃, the operating pressure is 35bar, 93wt% of the sugar resources permeate through the nanofiltration membrane, and 7wt% of the sugar resources remain in nanofiltration retentate B.

[0049] Step 32: The nanofiltration permeate C is piped to the chromatographic separation device 3 for separation. After separation, extract D and raffinate E are obtained. Extract D is then subjected to evaporation concentration, crystallization, and centrifugation to obtain hygroscopic sugar and centrifuged mother liquor F with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 70°C, and the feed composition was 60 wt% refractive index, 33 wt% arabinose, 25 wt% glucose, and 16 wt% galactose. In extract D, the arabinose content was 88 wt%, with an arabinose yield >90 wt%. In raffinate E, the arabinose content was 3 wt% and the glucose content was 41 wt%.

[0050] Step 33: After the molasses is transported to the dryer 7 for drying, L-arabinose crystals G with the required purity of 99.2% are obtained.

[0051] Step 34: The centrifuged mother liquor F and the residue E are respectively sent to enzyme catalysis tank 8 for mixing. Enzyme preparation is added to enzyme catalysis tank 8 for enzyme catalysis treatment to obtain ketose solution. The ketose solution is then subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped membrane evaporation treatment to obtain the desired high red finger caramel color liquid product H. In the enzyme catalysis treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 5% of the mixed solution mass ratio, the reaction pH is 7, the reaction temperature is 70℃, and the reaction time is 100min. In the browning reaction treatment, the reaction aid used is a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:2:7. The reaction process is controlled as follows: first adjust the pH to 7.0, then raise the temperature to 95℃ and react for 30min, then raise the temperature to 150℃ and react for 2h, then raise the temperature to 170℃ and react for 1h, and then cool to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator 11 operates at a temperature of 40°C and a pressure of 7 bar; during wiped membrane evaporation, the wiped membrane evaporator 12 operates at a pressure of 4 bar and a vacuum of 90 kPa.

[0052] Comparative Example 1

[0053] Using the same xylose chromatographic residue A as in Example 1, L-arabinose was directly extracted. The centrifugation mother liquor F was reused. The specific steps included: decolorizing the xylose chromatographic residue A in raw material tank 1 with activated carbon, performing chromatographic separation, evaporation and concentration, and crystallization centrifugation to obtain L-arabinose crystals G. The centrifugation mother liquor F was then reused in raw material tank 1. The final product, L-arabinose, had a purity of 99%. The residue E was sold externally for use as a cheap syrup, resulting in an actual utilization rate of only 75% of the sugar resources.

[0054] Comparative Example 2

[0055] Caramel color was directly prepared using the same xylose chromatographic residue A as in Example 1. The specific steps included: treating xylose chromatographic residue A in raw material tank 1 with a browning reaction, flash evaporation, ultrafiltration membrane separation, and evaporation concentration to obtain a liquid caramel color product. The reaction aid used was a mixture of ammonium sulfite and sodium sulfite in a 2:1 ratio. The reaction process was controlled as follows: first, the pH was adjusted to 7.0, then the temperature was raised to 95°C for 30 min, then raised to 140°C for 3 h, then raised to 170°C for 1 h, and finally cooled to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator 11 operated at a temperature of 60°C and a pressure of 5 bar. During wiped-film evaporation, the wiped-film evaporator 12 operated at a pressure of 5 bar and a vacuum of 90 kPa. The final caramel color liquid product obtained had a red index as high as 5.6 and a color rate of 20000 EBC.

[0056] The above comparison shows that, through improvements to the entire system and the L-arabinose preparation method, the utilization rate of sugar resources in xylose chromatographic residue A has increased from 75% to 92%, resulting in a 4.33-fold increase in economic benefits. No activated carbon solid waste is generated, truly achieving "turning waste into treasure and making full use of resources" while maintaining green and efficient production. In addition to improving the comprehensive utilization value of xylose chromatographic residue, it also produces a high-value-added, nationally compliant high red finger caramel coloring liquid product H.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for co-producing L-arabinose and caramel color using xylose chromatographic residue, characterized in that, The system utilizes a xylose chromatographic residue to co-produce L-arabinose and caramel color. This system comprises a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation and concentration tank, a crystallization tank, a centrifuge, and a dryer, all connected sequentially by pipelines. The raw material tank stores the xylose chromatographic residue. The nanofiltration membrane separator decolorizes the flowing xylose chromatographic residue into a nanofiltration cut-off liquid and a nanofiltration permeate. The chromatographic separation device separates the flowing nanofiltration permeate into an extract with a high arabinose content and a residue with a low arabinose content. The evaporation and concentration tank and the crystallization tank concentrate and crystallize the flowing extract into a sugar paste. The centrifuge separates the flowing sugar paste into humid sugar and a centrifugal mother liquor. The dryer dries the flowing humid sugar into L-arabinose crystals. The system also includes a browning reaction component for mixing the residue and the centrifugal mother liquor and then performing a browning reaction to prepare caramel color. The browning reaction assembly includes an enzyme catalytic tank, a browning reaction vessel, a flash evaporator, an ultrafiltration membrane separator, and a scraped membrane evaporator. The enzyme catalytic tank is used to mix the raffinate with the centrifuged mother liquor and then add enzyme preparations for enzyme catalysis to produce a ketose solution. The browning reaction vessel is used to brown the flowing ketose solution to produce crude caramel color. The flash evaporator is used to remove amino compounds or sulfite impurities from the flowing crude caramel color. The ultrafiltration membrane separator is used to remove 4-methylimidazole impurities from the flowing crude caramel color. The scraped membrane evaporator is used to concentrate the flowing crude caramel color at low temperature to produce a high red finger caramel color liquid product. The method includes the following steps: Step 1: The xylose chromatography residue in the raw material tank is transferred to a nanofiltration membrane separator through a pipeline for decolorization. After decolorization, nanofiltration retentate and nanofiltration permeate are obtained, wherein the transmittance of the nanofiltration permeate is >95%. Step 2: The nanofiltration permeate is transported through a pipeline to a chromatographic separation device for separation. After separation, an extract and a residue are obtained. The extract is then subjected to evaporation and concentration, crystallization, and centrifugation to obtain hygroscopic sugar and a centrifuged mother liquor with a refractive index >70%. Step 3: After the molasses is transported to a dryer for drying, L-arabinose crystals with the required purity >99% are obtained; Step 4: The centrifuged mother liquor and the residue are separately sent to an enzyme catalytic tank for mixing. Enzyme preparation is added to the enzyme catalytic tank for enzyme catalytic treatment to obtain ketose solution. The ketose solution is then subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped membrane evaporation treatment in sequence to obtain the desired high red finger caramel color liquid product.

2. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, In step one, the dry matter percentage concentration (i.e., sugar concentration) of the xylose chromatography residue is 70-80 wt%, the transmittance is 20-40%, and the conductivity is 5-10 μS / cm. Specifically, the dry matter contains 28-30 wt% arabinose, 26-33 wt% glucose, 5-10 wt% xylose, 4-6 wt% mannose, and 14-16 wt% galactose. During nanofiltration decolorization, the nanofiltration membrane separator operates at a temperature of 40-60°C and a pressure of 25-35 bar. More than 90 wt% of the sugars permeate through the nanofiltration membrane, while less than 10 wt% remain in the nanofiltration retentate.

3. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, In step two, during the separation process, commercially available resin is used, water is used as the eluent, the separation temperature is 50-70℃, the feed refractive index is 50-60 wt%, arabinose content is 27-33 wt%, glucose content is 25-30 wt%, and galactose content is 10-16 wt%. In the extracted liquid after separation, the arabinose content is >85 wt%, the arabinose yield is >90 wt%, and in the raffinate, the arabinose content is <5 wt% and the glucose content is >40 wt%.

4. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, In step four, during the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, with an enzyme addition amount of 1-5% of the mixed solution mass ratio, a reaction pH of 6-7, a reaction temperature of 60-70℃, and a reaction time of 100-150 min. During the browning reaction treatment, the reaction aids used are ammonia, ammonium carbonate, or a mixture of ammonium bicarbonate and ammonium sulfite or sodium metabisulfite, with a mixture ratio of 1:4:5 to 1:2:

7. The reaction process is controlled as follows: first adjust the pH to 6. The temperature is initially set at 0~7.0℃, then increased to 85~95℃ for 30~50 min, followed by a further increase to 130~150℃ for 2~4 h, then increased to 150~170℃ for 1~2 h, and finally cooled to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator operates at a temperature of 40~60℃ and a pressure of 5~7 bar. During wiped-film evaporation, the wiped-film evaporator operates at an evaporation pressure of 4~5 bar and a vacuum of 80~90 kPa.

5. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, The method includes the following steps: Step 11: The xylose chromatography residue in the raw material tank is transported to a nanofiltration membrane separator through a pipeline for decolorization. After decolorization, nanofiltration retentate and nanofiltration permeate are obtained. The transmittance of the nanofiltration permeate is >95%. The dry matter percentage concentration (sugar concentration) of the xylose chromatography residue is 70wt%, the transmittance is 30%, and the conductivity is 5μs / cm. In the dry matter, arabinose contains 30wt%, glucose contains 26wt%, xylose contains 8wt%, mannose contains 4wt%, and galactose contains 15wt%. During the nanofiltration decolorization process, the operating temperature of the nanofiltration membrane separator is 60℃, the operating pressure is 35bar, 92wt% of the sugar resources permeate through the nanofiltration membrane, and 8wt% of the sugar resources remain in the nanofiltration retentate. Step 12: The nanofiltration permeate is piped to a chromatographic separation device for separation. After separation, an extract and a raffinate are obtained. The extract is then subjected to evaporation and concentration, crystallization, and centrifugation to obtain hygroscopic sugar and a centrifuged mother liquor with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 60°C, and the feed contained 50 wt% refractive index, 31 wt% arabinose, 27 wt% glucose, and 16 wt% galactose. In the extract, the arabinose content was 86 wt%, with an arabinose yield >90 wt%. In the raffinate, the arabinose content was 4 wt% and the glucose content was 45 wt%. Step 13: After the molasses is transported to a dryer for drying, L-arabinose crystals with the required purity of 99.2% are obtained; Step 14: The centrifuged mother liquor and the residue are separately mixed in an enzyme catalytic tank. Enzyme preparation is added to the tank for enzyme catalytic treatment to obtain a ketose solution. The ketose solution is then subjected to browning reaction, flash evaporation, ultrafiltration membrane separation, and scraped membrane evaporation to obtain the desired high-red-finger caramel coloring liquid product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, with an enzyme addition rate of 3% of the mixed solution mass ratio. The reaction pH is 6, the reaction temperature is 60℃, and the reaction time is 150 min. During the browning reaction... The reaction aids used were a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:2:

7. The reaction process was controlled as follows: first, the pH was adjusted to 7.0, then the temperature was raised to 95℃ for 30 min, then raised to 140℃ for 3 h, then raised to 170℃ for 1 h, and finally cooled to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator operated at a temperature of 60℃ and a pressure of 5 bar. During wiped membrane evaporation, the wiped membrane evaporator operated at a pressure of 5 bar and a vacuum of 90 kPa.

6. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, The method includes the following steps: Step 21: The xylose chromatography residue in the raw material tank is transported to a nanofiltration membrane separator through a pipeline for decolorization. After decolorization, nanofiltration retentate and nanofiltration permeate are obtained. The transmittance of the nanofiltration permeate is >95%. The dry matter percentage concentration (sugar concentration) of the xylose chromatography residue is 80wt%, the transmittance is 40%, and the conductivity is 10μs / cm. In the dry matter, arabinose contains 28wt%, glucose contains 33wt%, xylose contains 5wt%, mannose contains 6wt%, and galactose contains 14wt%. During the nanofiltration decolorization process, the operating temperature of the nanofiltration membrane separator is 40℃, the operating pressure is 25bar, 90wt% of the sugar resources permeate through the nanofiltration membrane, and 10wt% of the sugar resources remain in the nanofiltration retentate. Step 22: The nanofiltration permeate is piped to a chromatographic separation device for separation. After separation, an extract and a raffinate are obtained. The extract is then subjected to evaporation and concentration, crystallization, and centrifugation to obtain hygroscopic sugar and a centrifuged mother liquor with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 50°C, and the feed contained 50 wt% refractive index, 27 wt% arabinose, 30 wt% glucose, and 10 wt% galactose. In the extract, the arabinose content was 86 wt%, with an arabinose yield >90 wt%. In the raffinate, the arabinose content was 5 wt% and the glucose content was 45 wt%. Step 23: After the molasses is transported to a dryer for drying, L-arabinose crystals with the required purity of 99.2% are obtained; Step 24: The centrifuged mother liquor and the residue are separately mixed in an enzyme catalytic tank. Enzyme preparation is added to the tank for enzyme catalytic treatment to obtain a ketose solution. The ketose solution is then subjected to browning reaction, flash evaporation, ultrafiltration membrane separation, and scraped membrane evaporation to obtain the desired high-red-finger caramel coloring liquid product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, with an enzyme addition rate of 1% of the mixed solution mass ratio. The reaction pH is 6, the reaction temperature is 60℃, and the reaction time is 150 min. During the browning reaction... The reaction aids used were a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:4:

5. The reaction process was controlled as follows: first, the pH was adjusted to 6.0, then the temperature was raised to 85℃ for 50 min, then raised to 130℃ for 4 h, then raised to 150℃ for 2 h, and finally cooled to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator operated at a temperature of 60℃ and a pressure of 5 bar. During wiped membrane evaporation, the wiped membrane evaporator operated at a pressure of 5 bar and a vacuum of 80 kPa.

7. The method for co-producing L-arabinose and caramel color using xylose chromatographic residue as described in claim 1, characterized in that, The method includes the following steps: Step 31: The xylose chromatography residue in the raw material tank is transported to a nanofiltration membrane separator through a pipeline for decolorization. After decolorization, nanofiltration retentate and nanofiltration permeate are obtained. The transmittance of the nanofiltration permeate is >95%. The dry matter percentage concentration (sugar concentration) of the xylose chromatography residue is 70 wt%, the transmittance is 20%, and the conductivity is 5 μS / cm. In the dry matter, arabinose contains 30 wt%, glucose contains 33 wt%, xylose contains 10 wt%, mannose contains 4 wt%, and galactose contains 16 wt%. During the nanofiltration decolorization process, the operating temperature of the nanofiltration membrane separator is 60℃, the operating pressure is 35 bar, 93 wt% of the sugar resources permeate through the nanofiltration membrane, and 7 wt% of the sugar resources remain in the nanofiltration retentate. Step 32: The nanofiltration permeate is piped to a chromatographic separation device for separation. After separation, an extract and a raffinate are obtained. The extract is then subjected to evaporation and concentration, crystallization, and centrifugation to obtain hygroscopic sugar and a centrifuged mother liquor with a refractive index of 72%. During the separation process, commercially available resin was used, water was used as the eluent, the separation temperature was 70°C, and the feed contained 60 wt% refractive index, 33 wt% arabinose, 25 wt% glucose, and 16 wt% galactose. In the extract, the arabinose content was 88 wt%, with an arabinose yield >90 wt%. In the raffinate, the arabinose content was 3 wt% and the glucose content was 41 wt%. Step 33: After the molasses is transported to a dryer for drying, L-arabinose crystals with the required purity of 99.2% are obtained; Step 34: The centrifuged mother liquor and the residue are separately mixed in an enzyme catalytic tank. Enzyme preparation is added to the tank for enzyme catalytic treatment to obtain a ketose solution. The ketose solution is then subjected to browning reaction, flash evaporation, ultrafiltration membrane separation, and scraped membrane evaporation to obtain the desired high-red-finger caramel coloring liquid product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, with an enzyme addition rate of 5% of the mixed solution mass ratio. The reaction pH is 7, the reaction temperature is 70℃, and the reaction time is 100 min. During the browning reaction... The reaction aids used were a mixture of ammonium carbonate, ammonium sulfite, and sodium metabisulfite in a ratio of 1:2:

7. The reaction process was controlled as follows: first, the pH was adjusted to 7.0, then the temperature was raised to 95℃ for 30 min, then raised to 150℃ for 2 h, then raised to 170℃ for 1 h, and finally cooled to room temperature. During ultrafiltration membrane separation, the ultrafiltration membrane separator operated at a temperature of 40℃ and a pressure of 7 bar. During wiped membrane evaporation, the wiped membrane evaporator operated at a pressure of 4 bar and a vacuum of 90 kPa.

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