System and method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate

Abstract

The invention belongs to the technical field of sugar alcohol preparation, and relates to a system and a method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate, the system comprises a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation concentration tank, a crystallization tank, a centrifugal separator and a dryer which are sequentially communicated by pipelines, and the browning reaction assembly is used for mixing the raffinate and the centrifugal mother liquor and then carrying out browning reaction treatment to prepare caramel pigment. The chromatographic separation device is used for separating an extracting solution and raffinate from the flowing nanofiltration permeate, the evaporation concentration tank and the crystallizing tank are used for concentrating and crystallizing the flowing extracting solution into massecuite, the centrifugal separator is used for separating the flowing massecuite into moist sugar and centrifugal mother liquor, and the dryer is used for drying the flowing moist sugar into L-arabinose crystals. The raffinate and the centrifugal mother liquor are mixed to prepare the caramel pigment liquid product, so that the utilization rate of saccharide resources is increased, and meanwhile, the caramel pigment additional product is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of sugar alcohol preparation, and particularly relates to a system and method for co-producing L-arabinose and caramel pigment by utilizing xylose chromatography raffinate. Background Art

[0002] In the process of preparing xylose from corn cobs as raw materials, a large amount of xylose mother liquor will be obtained during the centrifugation process. The xylose mother liquor can be subjected to chromatographic separation treatment to extract xylose again. During the chromatographic separation process, a raffinate is obtained at the same time, which is the xylose chromatographic separation raffinate. The xylose chromatographic separation raffinate contains about 30wt% arabinose, about 30wt% glucose, about 10wt% xylose, 15wt% galactose and a small amount of mannose and other sugar resources. The content fluctuates due to production conditions and batches, so it is difficult to use it reasonably. At present, most of the xylose chromatographic separation raffinate is sold as mixed syrup, with low added value.

[0003] L-arabinose, also known as gum aldose and pectinose, is a pentose with a chemical formula of C5H 10 O5. The preparation of L-arabinose can be traced back to the early 20th century, when arabinose was mainly isolated from some plant gums. With the development of technology, the technology of recovering arabinose from sugar byproducts (xylose mother liquor, chromatographic separation liquid, etc.) has gradually become mainstream. However, a large amount of solid waste is generated during the production of L-arabinose, and subsequent chromatographic raffinate, centrifugal mother liquor, etc. are difficult to effectively utilize.

[0004] Caramel color is a dark brown mixture of sugar substances produced at high temperature and widely used in foods such as soy sauce and vinegar. When used in soy sauce or braised sauce, the red index of caramel color is relatively high, generally the red index needs to be greater than 6.3 (when the color rate is 20000 EBC). Therefore, the preparation of this type of high red index caramel color generally requires hexose with a longer carbon chain. In addition to arabinose and a small amount of xylose, the rest of the xylose chromatographic extract is basically hexose, which has the potential to prepare high red index caramel color. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a system and method for co-producing L-arabinose and caramel pigment by utilizing xylose chromatography raffinate, wherein the raffinate and the centrifugal mother liquor are mixed to prepare a caramel pigment liquid product, thereby improving the utilization rate of sugar resources and obtaining a caramel pigment additional product, thereby improving the comprehensive utilization value of the xylose chromatography raffinate.

[0006] The present invention is achieved by providing a system for co-producing L-arabinose and caramel pigment by using xylose chromatographic raffinate, comprising a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation concentration tank, a crystallization tank, a centrifugal separator and a dryer which are sequentially connected by pipelines, wherein the raw material tank is used to store the xylose chromatographic raffinate, the nanofiltration membrane separator is used to decolorize the xylose chromatographic raffinate flowing through into a nanofiltration retentate and a nanofiltration permeate, the chromatographic separation device is used to separate the nanofiltration permeate flowing through into an extract with a high arabinose content and a raffinate with a low arabinose content, the evaporation concentration tank and the crystallization tank are used to concentrate and crystallize the extract flowing through into massecuite, the centrifugal separator is used to separate the massecuite flowing through into tidal sugar and a centrifugal mother liquor, and the dryer is used to dry the tidal sugar flowing through into L-arabinose crystals; the system also comprises a browning reaction component for mixing the raffinate with the centrifugal mother liquor and then performing a browning reaction treatment to prepare the caramel pigment.

[0007] Furthermore, the browning reaction component includes an enzyme catalytic tank, a browning reactor, a flash tank, an ultrafiltration membrane separator and a scraped film evaporator. The enzyme catalytic tank is used to mix the raffinate with the centrifuged mother liquor and then add the enzyme preparation to catalyze it into a ketose liquid. The browning reactor is used to brown the ketose liquid flowing through it into a crude caramel pigment. The flash tank is used to remove amino compounds or sulfite impurities from the crude caramel pigment flowing through it. The ultrafiltration membrane separator is used to remove 4-methylimidazole impurities from the crude caramel pigment flowing through it. The scraped film evaporator is used to concentrate the crude caramel pigment flowing through it at low temperature into a high red index caramel pigment liquid product.

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

[0009] The present invention is achieved by providing a method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate, characterized in that the system for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate as described above is used, and the method comprises the following steps: Step 1: The xylose chromatographic raffinate in the raw material tank is transported to a nanofiltration membrane separator through a pipeline for decolorization, and a nanofiltration retentate and a nanofiltration permeate are obtained after the decolorization, wherein the transmittance of the nanofiltration permeate is greater than 95%; Step 2: The nanofiltration permeate is transported to a chromatographic separation device through a pipeline for separation treatment, and an extract and a raffinate are obtained after the separation treatment. The extract is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor with a refractive index greater than 70%; Step 3: transporting the tidal sugar to a dryer for drying to obtain L-arabinose crystals with a purity of >99%; Step 4: Send the centrifuged mother liquor and the raffinate into an enzyme catalytic tank respectively for mixing, add an enzyme preparation into the enzyme catalytic tank for enzyme catalytic treatment to obtain a ketose solution, and subject the ketose solution to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped film evaporation treatment in sequence to obtain the desired high red index caramel pigment liquid product.

[0010] Compared with the prior art, the system and method for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate of the present invention has the following characteristics: 1. The existing process uses activated carbon for decolorization, which has high investment cost and pollutes the environment. However, the present invention uses a nanofiltration membrane separation process to decolorize the xylose chromatography raffinate, which can avoid the generation of solid waste and dust and reduce production costs; 2. The raffinate and centrifugal mother liquor in the L-arabinose extraction process are prepared into a high red index caramel pigment liquid product with a red index of up to 6.3 (when the color rate is 20,000 EBC). The comprehensive utilization rate of sugar resources can reach more than 92%. The xylose chromatography raffinate with a selling price of 1,500 yuan / ton is converted into 40,000 yuan / ton L-arabinose crystals and 3,000 yuan / ton high red index caramel pigment liquid products, which increases the economic benefits by 3 to 5 times and avoids the low-value utilization of sugar resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the principle of the system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate of the present invention; Figure 2 The figure is a schematic diagram of the process principle of the method for co-producing L-arabinose and caramel pigment by utilizing xylose chromatography raffinate. DETAILED DESCRIPTION

[0012] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0013] Please refer to Figure 1 As shown, a preferred embodiment of the system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate of the present invention comprises a raw material tank 1, a nanofiltration membrane separator 2, a chromatography separation device 3, an evaporation concentration tank 4, a crystallization tank 5, a centrifugal separator 6 and a dryer 7 which are sequentially connected by pipelines.

[0014] The raw material tank 1 is used to store the xylose chromatography raffinate A, the nanofiltration membrane separator 2 is used to decolorize the xylose chromatography raffinate A flowing through into the nanofiltration retentate B and the nanofiltration permeate C, and the chromatographic separation device 3 is used to separate the flowing nanofiltration permeate C into the extract D with high arabinose content and the raffinate E with low arabinose content. The evaporation concentration tank 4 and the crystallization tank 5 are used to concentrate and crystallize the flowing extract D into massecuite, the centrifugal separator 6 is used to separate the flowing massecuite into tidal sugar and centrifugal mother liquor F, and the dryer 7 is used to dry the flowing tidal sugar into L-arabinose crystals G.

[0015] The system also includes a browning reaction component for mixing the raffinate E with the centrifuged mother liquor F and then performing a browning reaction treatment to prepare caramel pigment. The browning reaction component includes an enzyme catalytic tank 8, a browning reactor 9, a flash tank 10, an ultrafiltration membrane separator 11 and a scraped film evaporator 12.

[0016] The enzyme catalysis tank 8 is used to mix the raffinate E with the centrifuged mother liquor F and then add the enzyme preparation to catalyze it into ketose liquid, the browning reactor 9 is used to brown the ketose liquid flowing through it into a crude caramel color, the flash tank 10 is used to remove amino compounds or sulfite impurities from the crude caramel color flowing through it, the ultrafiltration membrane separator 11 is used to remove 4-methylimidazole impurities from the crude caramel color flowing through it, and the scraped film evaporator 12 is used to low-temperature concentrate the crude caramel color flowing through it into a high red index caramel color liquid H product.

[0017] Wherein, the enzyme preparation is glucose isomerase.

[0018] Please also refer to Figure 1 and Figure 2 As shown, the present invention also discloses a method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate, which uses the system for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate as described above, and the method comprises the following steps: Step 1: The xylose chromatography raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization. After the decolorization, a nanofiltration retentate B and a nanofiltration permeate C are obtained, wherein the transmittance of the nanofiltration permeate C is >95%.

[0019] Step 2: The nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment. After the separation treatment, an extract D and a raffinate E are obtained. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor F with a refractive index greater than 70%.

[0020] Step 3: After the arabinose is transported to the dryer 7 for drying, the desired L-arabinose crystals G with a purity of >99% are obtained.

[0021] Step 4: The centrifuged mother liquor F and the raffinate E are respectively sent to the enzyme catalysis tank 8 for mixing, and the enzyme preparation is added to the enzyme catalysis tank 8 for enzyme catalysis to obtain a ketose solution. The ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the desired high red index caramel pigment liquid H product.

[0022] In the step 1, the dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration, is 70-80wt%, the light transmittance is 20-40%, and the conductivity is 5-10μs / cm. Among them, in the dry matter, arabinose contains 28-30wt%, glucose contains 26-33wt%, xylose contains 5-10%wt, mannose contains 4-6wt%, and galactose contains 14-16wt%. During the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 40-60°C, the operating pressure is 25-35bar, and more than 90wt% of the sugar resources pass through the nanofiltration membrane, and less than 10wt% of the sugar resources remain in the nanofiltration retentate B.

[0023] In the step 2, during the separation treatment, commercially available resin is used, water is used as the eluent, the separation temperature is 50-70°C, the feed refractive index is 50-60wt%, the arabinose content is 27-33wt%, the glucose content is 25-30wt%, and the galactose content is 10-16wt%. In the separated extract D, the arabinose content is >85wt%, and the arabinose yield is >90wt%; in the raffinate E, the arabinose content is <5wt%, and the glucose content is >40wt%.

[0024] In the step 4, during the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 1-5% of the mixed solution mass ratio, the reaction pH is 6-7, the reaction temperature is 60-70°C, and the reaction time is 100-150min. During the browning reaction treatment, the reaction aid used is a compound of ammonia water, ammonium carbonate or ammonium bicarbonate with ammonium sulfite and sodium pyrosulfite, and the compounding ratio is 1:4:5-1:2:7; the reaction process is regulated as follows: first adjust the pH to 6.0-7.0, then heat to 85-95°C for 30-50min, then heat to 130-150°C for 2-4h, then heat to 150-170°C for 1-2h, and then cool to room temperature. During the ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator 11 is 40-60°C and the operating pressure is 5-7bar. 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.

[0025] The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate of the present invention is further illustrated by specific examples below.

[0026] Example 1

[0027] Please refer to Figure 1 and Figure 2 As shown, the first embodiment of the method of the present invention for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate, the method comprises the following steps: Step 11, the xylose chromatographic raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization treatment, and the nanofiltration retentate B and the nanofiltration permeate C are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate C is>95%. The dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration is 70wt%, the transmittance is 30%, and the conductivity is 5μs / cm, wherein, in the dry matter, arabinose contains 30wt%, glucose contains 26wt%, xylose contains 8%wt, mannose contains 4wt%, and galactose contains 15wt%. During the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 50°C, the operating pressure is 30bar, 92wt% of the sugar resources pass through the nanofiltration membrane, and 8wt% of the sugar resources remain in the nanofiltration retentate B.

[0028] Step 12, the nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment, and the extract D and the raffinate E are obtained after the separation treatment. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor F with a refractive index of 72%. During the separation treatment, commercially available resin is used, water is used as the eluent, the separation temperature is 60°C, the feed refractive index is 55wt%, the arabinose content is 31wt%, the glucose content is 27wt%, and the galactose content is 16wt%. In the extract D, the arabinose content is 87wt%, and the arabinose yield is>90wt%. In the raffinate E, the arabinose content is 4wt%, and the glucose content is 43wt%.

[0029] Step 13: After the arabinose is transported to the dryer 7 for drying, the desired L-arabinose crystals G with a purity of 99.2% are obtained.

[0030] Step 14, the centrifugal mother liquor F and the raffinate E are respectively sent to the enzyme catalytic tank 8 for mixing, and the enzyme preparation is added to the enzyme catalytic tank 8 for enzyme catalytic treatment to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the required high red caramel pigment liquid H product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 3% of the mixed liquid mass ratio, the reaction pH is 6.5, the reaction temperature is 65 ° C, and the reaction time is 130min. During the browning reaction treatment, the reaction aid used is a compound of ammonium carbonate, ammonium sulfite, and sodium pyrosulfite, and the compounding ratio is 1:3:6. The reaction process is regulated as follows: first adjust the pH to 6.5, then heat to 90 ° C for reaction for 40min, then heat to 140 ° C for reaction for 3h, then heat to 160 ° C for reaction for 1.5h, and then cool to room temperature. During the ultrafiltration membrane separation process, the operating temperature of the ultrafiltration membrane separator 11 is 50° C. and the operating pressure is 6 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 85 kPa.

[0031] Example 2

[0032] Please refer to Figure 1 and Figure 2 As shown, the second embodiment of the method of the present invention for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate, the method comprises the following steps: Step 21, the xylose chromatographic raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization treatment, and the nanofiltration retentate B and the nanofiltration permeate C are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate C is>95%. The dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration is 80wt%, the transmittance is 40%, and the conductivity is 10μs / cm, wherein, in the dry matter, arabinose contains 28wt%, glucose contains 33wt%, xylose contains 5%wt, mannose contains 6wt%, and galactose contains 14wt%. During the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 40°C, the operating pressure is 25bar, 90wt% of the sugar resources pass through the nanofiltration membrane, and 10wt% of the sugar resources remain in the nanofiltration retentate B.

[0033] Step 22, the nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment, and an extract D and a raffinate E are obtained after separation treatment. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor F with a refractive index of 72%. During the separation treatment, commercially available resin is used, water is used as the eluent, the separation temperature is 50°C, the feed refractive index is 50wt%, the arabinose content is 27wt%, the glucose content is 30wt%, and the galactose content is 10wt%. In the extract D, the arabinose content is 86wt%, and the arabinose yield is>90wt%. In the raffinate E, the arabinose content is 5wt%, and the glucose content is 45wt%.

[0034] Step 23: After the arabinose is transported to the dryer 7 for drying, the desired L-arabinose crystals G with a purity of 99.2% are obtained.

[0035] Step 24, the centrifugal mother liquor F and the raffinate E are respectively sent to the enzyme catalytic tank 8 for mixing, and the enzyme preparation is added to the enzyme catalytic tank 8 for enzyme catalytic treatment to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the required high red caramel pigment liquid H product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 1% of the mixed liquid mass ratio, the reaction pH is 6, the reaction temperature is 60°C, and the reaction time is 150min. During the browning reaction treatment, the reaction aid used is a compound of ammonium carbonate, ammonium sulfite, and sodium pyrosulfite, and the compounding ratio is 1:4:5. The reaction process is regulated as follows: first adjust the pH to 6.0, then heat to 85°C for reaction for 50min, then heat to 130°C for reaction for 4h, then heat to 150°C for reaction for 2h, and then cool to room temperature. During the ultrafiltration membrane separation process, the operating temperature of the ultrafiltration membrane separator 11 is 60° C. and the operating pressure is 5 bar; during the scraped film evaporation process, the evaporation pressure of the scraped film evaporator 12 is 5 bar and the vacuum degree is 80 kPa.

[0036] Example 3

[0037] Please refer to Figure 1 and Figure 2 As shown, the third embodiment of the method of the present invention for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate, the method comprises the following steps: Step 31, the xylose chromatographic raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization treatment, and the nanofiltration retentate B and the nanofiltration permeate C are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate C is greater than 95%. The dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration, is 70wt%, the transmittance is 20%, and the conductivity is 5μs / cm, wherein, in the dry matter, arabinose contains 30wt%, glucose contains 33wt%, xylose contains 10%wt, mannose contains 4wt%, and galactose contains 16wt%. During the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 60°C, the operating pressure is 35bar, 93wt% of the sugar resources pass through the nanofiltration membrane, and 7wt% of the sugar resources remain in the nanofiltration retentate B.

[0038] Step 32, the nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment, and the extract D and the raffinate E are obtained after the separation treatment. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor F with a refractive index of 72%. During the separation treatment, commercially available resin is used, water is used as the eluent, the separation temperature is 70°C, the feed refractive index is 60wt%, the arabinose content is 33wt%, the glucose content is 25wt%, and the galactose content is 16wt%. In the extract D, the arabinose content is 88wt%, and the arabinose yield is>90wt%. In the raffinate E, the arabinose content is 3wt%, and the glucose content is 41wt%.

[0039] Step 33: After the arabinose is transported to the dryer 7 for drying, the desired L-arabinose crystals G with a purity of 99.2% are obtained.

[0040] Step 34, the centrifugal mother liquor F and the raffinate E are respectively sent to the enzyme catalytic tank 8 for mixing, and the enzyme preparation is added to the enzyme catalytic tank 8 for enzyme catalytic treatment to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the desired high red caramel pigment liquid H product. During the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 5% of the mixed liquid mass ratio, the reaction pH is 7, the reaction temperature is 70°C, and the reaction time is 100min. During the browning reaction treatment, the reaction aid used is a compound of ammonium carbonate, ammonium sulfite, and sodium pyrosulfite, and the compounding ratio is 1:2:7. The reaction process is regulated as follows: first adjust the pH to 7.0, then heat to 95°C for reaction for 30min, then heat to 150°C for reaction for 2h, then heat to 170°C for reaction for 1h, and then cool to room temperature. During the ultrafiltration membrane separation process, the operating temperature of the ultrafiltration membrane separator 11 is 40° C. and the operating pressure is 7 bar; during the scraped film evaporation process, the evaporation pressure of the scraped film evaporator 12 is 4 bar and the vacuum degree is 90 kPa.

[0041] Comparative Example 1

[0042] The same xylose chromatography raffinate A as in Example 1 is used as a raw material to directly extract L-arabinose, and the centrifugal mother liquor F is recycled for use. The specific steps include: the xylose chromatography raffinate A in the raw material tank 1 is subjected to activated carbon decolorization, chromatography separation, evaporation concentration, and crystallization centrifugation to obtain L-arabinose crystals G, and the centrifugal mother liquor F is recycled to the raw material tank 1 for repeated use. The purity of the final L-arabinose product is 99%. The raffinate E is sold as cheap syrup, and the actual utilization rate of sugar resources is only 75%.

[0043] Comparative Example 2

[0044] The same xylose chromatographic raffinate A as in Example 1 is used as a raw material to directly prepare caramel pigment, and the specific steps include: the xylose chromatographic raffinate A raw material in the raw material tank 1 is subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and evaporation concentration treatment to prepare a caramel pigment liquid product. The reaction aid used is a compound of ammonium sulfite and sodium sulfite, and the compounding ratio is 2:1. The reaction process is regulated as follows: first adjust the pH to 7.0, then heat to 95°C for reaction for 30min, then heat to 140°C for reaction for 3h, then heat to 170°C for reaction for 1h, and then cool to room temperature. During the ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator 11 is 60°C and the operating pressure is 5bar. During the scraping film evaporation treatment, the evaporation pressure of the scraping film evaporator 12 is 5bar and the vacuum degree is 90kpa. Finally, a caramel pigment liquid product is prepared, with a red index of up to 5.6 and a color rate of 20000EBC.

[0045] Through the above comparison, it can be seen that the present invention improves the entire system and the L-arabinose preparation method, the utilization rate of sugar resources in the xylose chromatography raffinate A is increased from 75% to 92%, the economic benefit can be increased by 4.33 times, no activated carbon solid waste is generated, and the green and efficient production is truly achieved while "turning waste into treasure and making full use of it". While improving the comprehensive utilization value of the xylose chromatography raffinate, a high-value-added, high-red-finger caramel pigment liquid H product that meets national standards is prepared.

[0046] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate, characterized in that: The invention comprises a raw material tank, a nanofiltration membrane separator, a chromatographic separation device, an evaporation concentration tank, a crystallization tank, a centrifugal separator and a dryer which are sequentially connected by pipelines. The raw material tank is used to store xylose chromatographic raffinate, the nanofiltration membrane separator is used to decolorize the xylose chromatographic raffinate flowing through into nanofiltration retentate and nanofiltration permeate, the chromatographic separation device is used to separate the nanofiltration permeate flowing through into an extract with high arabinose content and a raffinate with low arabinose content, the evaporation concentration tank and the crystallization tank are used to concentrate and crystallize the extract flowing through into massecuite, the centrifugal separator is used to separate the massecuite flowing through into tidal sugar and centrifugal mother liquor, and the dryer is used to dry the tidal sugar flowing through into L-arabinose crystals; the system also comprises a browning reaction component for mixing the raffinate with the centrifugal mother liquor and then performing a browning reaction treatment to prepare a caramel pigment.

2. The system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate according to claim 1, characterized in that: The browning reaction component comprises an enzyme catalytic tank, a browning reaction kettle, a flash tank, an ultrafiltration membrane separator and a scraped film evaporator. The enzyme catalytic tank is used to mix the raffinate with the centrifuged mother liquor and then add the enzyme preparation to catalyze the mixture into a ketose liquid. The browning reaction kettle is used to brown the ketose liquid flowing through to form a crude caramel pigment. The flash tank is used to remove amino compounds or sulfite impurities from the crude caramel pigment flowing through. The ultrafiltration membrane separator is used to remove 4-methylimidazole impurities from the crude caramel pigment flowing through. The scraped film evaporator is used to concentrate the crude caramel pigment flowing through at low temperature into a high red index caramel pigment liquid product.

3. The system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate according to claim 2, characterized in that: The enzyme preparation is glucose isomerase.

4. A method for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate, characterized in that: The method uses the system for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate as claimed in claim 2, and the method comprises the following steps: Step 1: The xylose chromatographic raffinate in the raw material tank is transported to a nanofiltration membrane separator through a pipeline for decolorization, and a nanofiltration retentate and a nanofiltration permeate are obtained after the decolorization, wherein the transmittance of the nanofiltration permeate is greater than 95%; Step 2: The nanofiltration permeate is transported to a chromatographic separation device through a pipeline for separation treatment, and an extract and a raffinate are obtained after the separation treatment. The extract is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor with a refractive index greater than 70%; Step 3: transporting the tidal sugar to a dryer for drying to obtain L-arabinose crystals with a purity of >99%; Step 4: Send the centrifuged mother liquor and the raffinate into an enzyme catalytic tank respectively for mixing, add an enzyme preparation into the enzyme catalytic tank for enzyme catalytic treatment to obtain a ketose solution, and subject the ketose solution to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraped film evaporation treatment in sequence to obtain the desired high red index caramel pigment liquid product.

5. The method for co-producing L-arabinose and caramel pigment using xylose chromatography raffinate according to claim 4, characterized in that: In the step 1, the dry matter mass percentage concentration of the xylose chromatographic raffinate, i.e., the sugar concentration, is 70-80wt%, the transmittance is 20-40%, and the conductivity is 5-10μs / cm, wherein, in the dry matter, arabinose contains 28-30wt%, glucose contains 26-33wt%, xylose contains 5-10%wt, mannose contains 4-6wt%, and galactose contains 14-16wt%; during the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator is 40-60°C, the operating pressure is 25-35bar, more than 90wt% of the sugar resources pass through the nanofiltration membrane, and less than 10wt% of the sugar resources remain in the nanofiltration retentate.

6. The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate according to claim 4, characterized in that: In the step 2, during the separation treatment, commercially available resin is used, water is used as the eluent, the separation temperature is 50-70°C, the feed refractive index is 50-60wt%, the arabinose content is 27-33wt%, the glucose content is 25-30wt%, and the galactose content is 10-16wt%; in the extract after separation, the arabinose content is >85wt%, the arabinose yield is >90wt%, and in the raffinate, the arabinose content is <5wt%, and the glucose content is >40wt%.

7. The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate according to claim 4, characterized in that: In the step 4, during the enzyme catalysis treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 1-5% of the mixed solution mass ratio, the reaction pH is 6-7, the reaction temperature is 60-70°C, and the reaction time is 100-150min; during the browning reaction treatment, the reaction aid used is a mixture of ammonia water, ammonium carbonate or ammonium bicarbonate and ammonium sulfite, sodium pyrosulfite, and the mixture ratio is 1:4:5-1:2:

7. The reaction process is regulated as follows: first adjust the pH to 6 .0~7.0, then heat to 85~95℃ for reaction for 30~50min, then heat to 130~150℃ for reaction for 2~4h, then heat to 150~170℃ for reaction for 1~2h, then cool to room temperature; in ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator is 40~60℃, and the operating pressure is 5~7bar; in wiped film evaporation treatment, the evaporation pressure of the wiped film evaporator is 4~5bar, and the vacuum degree is 80~90kpa.

8. The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate according to claim 4, characterized in that: The method comprises the following steps: Step 11, the xylose chromatographic raffinate in the raw material tank is transported to the nanofiltration membrane separator through a pipeline for decolorization treatment, and a nanofiltration retentate and a nanofiltration permeate are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate is>95%; the dry matter mass percentage concentration of the xylose chromatographic raffinate, i.e., the sugar concentration is 70wt%, the transmittance is 30%, and the conductivity is 5μs / cm, wherein, in the dry matter, arabinose contains 30wt%, glucose contains 26wt%, xylose contains 8%wt, mannose contains 4wt%, and galactose contains 15wt%; during the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator is 60°C, the operating pressure is 35bar, 92wt% of the sugar resources pass through the nanofiltration membrane, and 8wt% of the sugar resources remain in the nanofiltration retentate; Step 12, transporting the nanofiltration permeate through a pipeline to a chromatographic separation device for separation treatment, obtaining an extract and a raffinate after separation treatment, and sequentially performing evaporation concentration treatment, crystallization treatment and centrifugal separation treatment on the extract to obtain tidal sugar and a centrifuge mother liquor with a refractive index of 72%; during the separation treatment, commercially available resin is used, water is used as an eluent, the separation temperature is 60° C., the feed refractive index is 50wt%, the arabinose content is 31wt%, the glucose content is 27wt%, and the galactose content is 16wt%; in the extract, the arabinose content is 86wt%, and the arabinose yield is>90wt%; in the raffinate, the arabinose content is 4wt%, and the glucose content is 45wt%; Step 13, conveying the tidal sugar to a dryer for drying to obtain the desired L-arabinose crystals with a purity of 99.2%; Step 14, the centrifuged mother liquor and the raffinate are respectively sent to an enzyme catalytic tank for mixing, an enzyme preparation is added to the enzyme catalytic tank for enzyme catalytic treatment to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the desired high red index caramel pigment liquid product; during the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 3% of the mixed solution mass ratio, the reaction pH is 6, the reaction temperature is 60°C, and the reaction time is 150min; during the browning reaction treatment, The reaction aid used is a compound 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 heat to 95°C for reaction for 30 minutes, then heat to 140°C for reaction for 3 hours, then heat to 170°C for reaction for 1 hour, and then cool to room temperature; during ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator is 60°C and the operating pressure is 5 bar; during scraped film evaporation treatment, the evaporation pressure of the scraped film evaporator is 5 bar and the vacuum degree is 90 kpa.

9. The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate according to claim 4, characterized in that: The method comprises the following steps: Step 21, the xylose chromatographic raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization treatment, and the nanofiltration retentate B and the nanofiltration permeate C are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate C is>95%; the dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration is 80wt%, the transmittance is 40%, and the conductivity is 10μs / cm, wherein, in the dry matter, arabinose contains 28wt%, glucose contains 33wt%, xylose contains 5%wt, mannose contains 6wt%, and galactose contains 14wt%; during the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 40°C, the operating pressure is 25bar, 90wt% of the sugar resources pass through the nanofiltration membrane, and 10wt% of the sugar resources remain in the nanofiltration retentate B; Step 22, the nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment, and an extract D and a raffinate E are obtained after the separation treatment. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifuge mother liquor F with a refractive index of 72%; during the separation treatment, commercially available resin is used, water is used as an eluent, the separation temperature is 50°C, the feed refractive index is 50wt%, the arabinose content is 27wt%, the glucose content is 30wt%, and the galactose content is 10wt%; in the extract D, the arabinose content is 86wt%, and the arabinose yield is>90wt%; in the raffinate E, the arabinose content is 5wt%, and the glucose content is 45wt%; Step 23, transporting the arabinose to the dryer 7 for drying to obtain the desired L-arabinose crystals G with a purity of 99.2%; Step 24, the centrifuged mother liquor F and the raffinate E are respectively sent to the enzyme catalytic tank 8 for mixing, and the enzyme preparation is added to the enzyme catalytic tank 8 for enzyme catalytic treatment to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the desired high red index caramel pigment liquid H product; during the enzyme catalytic treatment, the enzyme preparation used is glucose isomerase, the enzyme addition amount is 1% of the mixed solution mass ratio, the reaction pH is 6, the reaction temperature is 60°C, and the reaction time is 150min; during the browning reaction treatment The reaction aid used is a compound 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 heat to 85°C for reaction for 50 minutes, then heat to 130°C for reaction for 4 hours, then heat to 150°C for reaction for 2 hours, and then cool to room temperature; during ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator 11 is 60°C and the operating pressure is 5 bar; during scraped film evaporation treatment, the evaporation pressure of the scraped film evaporator 12 is 5 bar and the vacuum degree is 80 kPa.

10. The method for co-producing L-arabinose and caramel pigment by using xylose chromatography raffinate according to claim 4, characterized in that: The method comprises the following steps: Step 31, the xylose chromatographic raffinate A in the raw material tank 1 is transported to the nanofiltration membrane separator 2 through a pipeline for decolorization treatment, and the nanofiltration retentate B and the nanofiltration permeate C are obtained after the decolorization treatment, wherein the transmittance of the nanofiltration permeate C is>95%; the dry matter mass percentage concentration of the xylose chromatographic raffinate A, i.e., the sugar concentration is 70wt%, the transmittance is 20%, and the conductivity is 5μs / cm, wherein, in the dry matter, arabinose contains 30wt%, glucose contains 33wt%, xylose contains 10%wt, mannose contains 4wt%, and galactose contains 16wt%; during the nanofiltration decolorization treatment, the operating temperature of the nanofiltration membrane separator 2 is 60°C, the operating pressure is 35bar, 93wt% of the sugar resources pass through the nanofiltration membrane, and 7wt% of the sugar resources remain in the nanofiltration retentate B; Step 32, the nanofiltration permeate C is transported to the chromatographic separation device 3 through a pipeline for separation treatment, and an extract D and a raffinate E are obtained after the separation treatment. The extract D is sequentially subjected to evaporation concentration treatment, crystallization treatment and centrifugal separation treatment to obtain tidal sugar and a centrifugal mother liquor F with a refractive index of 72%; during the separation treatment, commercially available resin is used, water is used as an eluent, the separation temperature is 70°C, the feed refractive index is 60wt%, the arabinose content is 33wt%, the glucose content is 25wt%, and the galactose content is 16wt%; in the extract D, the arabinose content is 88wt%, and the arabinose yield is>90wt%; in the raffinate E, the arabinose content is 3wt%, and the glucose content is 41wt%; Step 33, transporting the arabinose to the dryer 7 for drying to obtain the desired L-arabinose crystals G with a purity of 99.2%; Step 34, the centrifuged mother liquor F and the raffinate E are respectively sent to the enzyme catalysis tank 8 for mixing, and the enzyme preparation is added to the enzyme catalysis tank 8 for enzyme catalysis to obtain a ketose solution, and the ketose solution is sequentially subjected to browning reaction treatment, flash evaporation treatment, ultrafiltration membrane separation treatment, and scraping film evaporation treatment to obtain the desired high red index caramel pigment liquid H product; during 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°C, and the reaction time is 100min; during the browning reaction treatment The reaction aid used is a compound 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 heat to 95°C for 30 minutes, then heat to 150°C for 2 hours, then heat to 170°C for 1 hour, and then cool to room temperature; during ultrafiltration membrane separation treatment, the operating temperature of the ultrafiltration membrane separator 11 is 40°C and the operating pressure is 7 bar; during scraped film evaporation treatment, the evaporation pressure of the scraped film evaporator 12 is 4 bar and the vacuum degree is 90 kPa.

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