Method for improving viscosity of caramel pigment
By controlling the catalyst ratio, pH value, reaction temperature and pressure, combined with compressed air backblowing technology, the time and temperature limitations in the process of increasing the viscosity of caramel pigments are solved, and the effect of efficiently improving viscosity and quality is achieved, while reducing production costs.
Patent Information
- Application Number
- CN202510385612.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-29
- Publication Date
- 2025-07-04
AI Technical Summary
In the process of increasing the viscosity of caramel pigments, the prior art often requires a longer reaction time and a higher reaction temperature, resulting in an increase in production costs and is prone to affect other properties of caramel pigments, such as solubility, stability and antioxidant properties.
By controlling the catalyst ratio, pH value, reaction temperature and pressure during the reaction, combined with compressed air backblowing technology, the stirring speed and exhaust valve opening in the reaction kettle without increasing the reaction time and temperature, the pressure in the reaction kettle is controlled, the exhaust gas is discharged, and the red index is monitored to terminate the reaction.
Effectively improve the viscosity of caramel pigments, increase yield and quality, reduce production costs, and avoid negative impacts on other properties.
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Figure SMS_1
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sugar alcohol preparation, and particularly relates to a method for increasing the viscosity of caramel pigment. Background Art
[0002] Caramel color is a kind of color widely used in food, beverage, medicine and cosmetics. It can not only increase the color of the product, but also enhance the flavor and taste of the product. In the fields of food chemistry, polymer materials and food additives, the viscosity of caramel color is a very important indicator because it directly affects the application effect and performance of caramel color. Generally speaking, the higher the viscosity of caramel color, the better its tinting power, stability, antioxidant and light resistance.
[0003] In the prior art, the method for improving the viscosity of caramel color mainly controls the molecular structure and molecular weight of caramel color in the reaction process by adjusting conditions such as reaction temperature, reaction time, reactant ratio and catalyst, thereby reaches the purpose of improving viscosity. In addition, some technical schemes are also provided to carry out post-treatment to caramel color after the reaction ends, such as drying, pulverizing, esterification, oxidation, etc., to change the physical and chemical properties of caramel color, thereby improving its viscosity. However, these methods often require longer reaction time and higher reaction temperature, which not only increases production cost, but also easily causes caramel color to darken, affecting its application effect. Existing physical or chemical post-treatment method, although can improve the viscosity of caramel color to a certain extent, often has a negative impact on other properties of caramel color, such as reducing its solubility, stability, antioxidation and light resistance, etc. Therefore, how to find a method that can effectively improve the viscosity of caramel color, and can not have a negative impact on its other properties, is an important problem urgently to be solved in the current food additive field. Summary of the invention
[0004] The technical problem to be solved by the present invention is to provide a method for increasing the viscosity of caramel pigment, which can effectively increase the viscosity of caramel pigment without increasing the reaction time and the reaction temperature, and will not have a negative impact on its other properties, thereby increasing the output and quality of caramel pigment and reducing production costs.
[0005] The present invention is achieved by providing a method for increasing the viscosity of caramel pigment, comprising the following steps: Step 1: Mix the catalyst with 3.85~7.20m 3The xylose mother liquor is put into the reaction kettle at a mass ratio of 15-25%, the pH in the reaction kettle is adjusted to 3.0-7.0, the browning reaction temperature is set at 100-150 °C, and at the same time, the stirring device of the reaction kettle is started to stir the feed liquid, and the browning reaction is started; wherein, the catalyst is ammonium sulfite with a mass ratio of 3.15-4.20% and sodium metabisulfite with a mass ratio of 9.73-13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0-6.0; Step 2: During the browning reaction, adjust the pH to not less than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, and keep the pressure in the reaction kettle at 0.01-0.1 MPa; Step 3: The browning reaction time is 5-10 h. At the end of the browning reaction, when the red index of the feed liquid in the reaction kettle is monitored to reach the expected value of 5.5-6.5, use compressed air to backflush the inside of the reaction kettle until the browning reaction ends.
[0006] Furthermore, the method for increasing the viscosity of caramel pigment includes the following steps: Step 11: Prepare a 15 m 3 reaction kettle, put the catalyst and 7.20 m 3 of the xylose mother liquor into the reaction kettle at a mass ratio of 15-25%, adjust the pH in the reaction kettle to 3.0-7.0, set the browning reaction temperature at 100-150 °C, and at the same time, start the stirring device of the reaction kettle to stir the feed liquid, and start the browning reaction; wherein, the catalyst is ammonium sulfite with a mass ratio of 4.20% and sodium metabisulfite with a mass ratio of 9.73%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0-6.0; Step 12: During the browning reaction, adjust the pH to not less than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, and keep the pressure in the reaction kettle at 0.01-0.1 MPa; Step 13: When the browning reaction time reaches 5-6 h and the red index of the feed liquid in the reaction kettle is monitored to reach the expected value of 5.5, and at this time the reaction kettle temperature > 130 °C, backflush with 0.6 ± 0.05 MPa compressed air for 40-60 minutes; after the backflush ends, if the reaction kettle temperature > 100 °C, then increase the compressed air pressure to 1.0 MPa and backflush for 10 minutes; after the backflush ends, if the reaction kettle temperature < 100 °C, then cool down normally until the browning reaction ends.
[0007] Furthermore, the method for increasing the viscosity of caramel pigment includes the following steps: Step 21: Prepare a 15 m 3 reaction kettle, put the catalyst and 5.50 m 3The xylose mother liquor is put into the reaction kettle according to a mass ratio of 15-25%, the pH in the reaction kettle is adjusted to 3.0-7.0, the browning reaction temperature is set at 100-150 °C, and at the same time, the stirring device of the reaction kettle is started to stir the feed liquid to initiate the browning reaction; among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0-6.0; Step 22. During the browning reaction, adjust the pH to not less than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve to keep the pressure in the reaction kettle at 0.01-0.1 MPa; Step 23. When the browning reaction time reaches 6-8 h and the red index of the feed liquid in the reaction kettle is monitored to reach the expected value of 6.0, and at this time the reaction kettle temperature > 130 °C, backflush with 0.6±0.05 MPa compressed air for 20-40 minutes; after the backflushing ends, if the reaction kettle temperature > 100 °C, then increase the compressed air pressure to 1.0 MPa and backflush for 10 minutes; after the backflushing ends, if the reaction kettle temperature < 100 °C, then cool down normally until the browning reaction ends.
[0008] Furthermore, the method for increasing the viscosity of caramel pigment includes the following steps: Step 31. Prepare a 15 m 3 reaction kettle, put the catalyst and 3.85 m 3 of the xylose mother liquor into the reaction kettle according to a mass ratio of 15-25%, adjust the pH in the reaction kettle to 3.0-7.0, set the browning reaction temperature at 100-150 °C, and at the same time, start the stirring device of the reaction kettle to stir the feed liquid to initiate the browning reaction; among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0-6.0; Step 32. During the browning reaction, adjust the pH to not less than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve to keep the pressure in the reaction kettle at 0.01-0.1 MPa; Step 33. When the browning reaction time reaches 8-10 h and the red index of the feed liquid in the reaction kettle is monitored to reach the expected value of 6.5, and at this time the reaction kettle temperature > 130 °C, backflush with 0.8±0.05 MPa compressed air for 20-30 minutes; after the backflushing ends, if the reaction kettle temperature > 100 °C, then increase the compressed air pressure to 1.0 MPa and backflush for 20 minutes; after the backflushing ends, if the reaction kettle temperature < 100 °C, then cool down normally until the browning reaction ends.
[0009] Compared with the prior art, the method for increasing the viscosity of caramel pigment of the present invention has the following characteristics: 1. During the cooling process at the end of the reaction, 1.0 MPa compressed air is used and acts together with stirring (rotation speed 1500 - 2000 rpm / min) to increase the viscosity of the caramel pigment. Without increasing the reaction time and reaction temperature, the viscosity of the caramel pigment can be effectively increased.
[0010] 2. During the reaction process, the opening degree of the tail gas valve is controlled to keep the pressure in the reaction kettle at 0.01 - 0.1 MPa, so as to take away waste gases such as sulfur dioxide generated during the reaction, effectively remove the waste gases generated during the reaction, and keep the pressure in the reaction kettle within a reasonable range.
[0011] 3. After the reaction ends, the waste gases generated during the reaction process are collected and treated in a timely manner to reduce environmental pollution, increase the yield and quality of the caramel pigment, and reduce production costs.
[0012] 4. During the reaction process, the feeding ratio of the reactants and the reaction conditions are strictly controlled to ensure the smooth progress of the reaction and achieve the expected viscosity, and to avoid negative impacts on other properties of the caramel pigment by existing physical or chemical post-treatment methods.
[0013] 5. During the reaction process, the feeding ratio of the reactants can be appropriately increased to increase the yield of the caramel pigment, but attention should be paid to controlling the reaction temperature and reaction time to avoid excessive decomposition and discoloration of the caramel pigment.
[0014] 6. During the reaction process, the reaction time can be appropriately extended to increase the viscosity of the caramel pigment, but attention should be paid to controlling the reaction temperature to avoid excessive decomposition and discoloration of the caramel pigment. Specific Embodiments
[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0016] A preferred embodiment of the method for increasing the viscosity of caramel pigment of the present invention includes the following steps: Step 1. The catalyst is 3.85 m 3 ~7.20 m 3The xylose mother liquor is put into the reaction kettle according to a mass ratio of 15 - 25%, the pH in the reaction kettle is adjusted to 3.0 - 7.0, the browning reaction temperature is set at 100 - 150 °C, and at the same time, the stirring device of the reaction kettle is started to stir the feed liquid, the initial stirring speed is controlled at 2400 rpm, and the browning reaction is started; among them, the catalyst is ammonium sulfite with a mass ratio of 3.15 - 4.20% and sodium metabisulfite with a mass ratio of 9.73 - 13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥ 8%, DE ≥ 80%, and pH is 3.0 - 6.0.
[0017] Step 2: During the browning reaction, adjust the pH not lower than 4.0, control the opening degree of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, and keep the pressure in the reaction kettle at 0.01 - 0.1 MPa.
[0018] Step 3: The browning reaction time is 5 - 10 h. At the end of the browning reaction, when it is monitored that the red index of the feed liquid in the reaction kettle reaches the expected value of 5.5 - 6.5, use compressed air to backflush the inside of the reaction kettle until the browning reaction ends.
[0019] In Step 3, the pressure of the compressed air is 1.0 MPa, the stirring rate is 1500 - 2000 rpm / min, and the waste gas such as sulfur dioxide generated during the browning reaction in the reaction kettle is discharged through the tail gas valve to increase the viscosity of the finished caramel pigment.
[0020] Among them, the red index is an index reflecting the red intensity of the caramel pigment product, and its measurement method is: accurately weigh 1.000 g of the caramel pigment sample, add 10 mL of distilled water, and stir and dissolve with a glass rod. Then transfer it into a 100 mL volumetric flask, wash the beaker with distilled water several times, pour the washing liquid into the volumetric flask, and finally make up the volume to 100 mL to obtain a 1% sample dilution. Then absorb 10 mL of the 1% sample dilution and pour it into a 100 mL volumetric flask, add distilled water to the scale, and shake well to obtain a 0.1% sample dilution. Since it is required to be clear and transparent, it must be centrifuged and filtered at 2400 r / min (or filtered with filter paper). Pour the treated 0.1% dilution sample into a 1 cm cuvette, use a 72 - 1 type spectrophotometer to measure its optical density OD1 value at 610 nm, measure it several times repeatedly, and take the average OD1 value. Adjust the wavelength to 510 nm, readjust the zero point, and measure its optical density as OD2. Calculate the red index of the sample according to the following formula: Red index = 10 * lg(OD2 / OD1).
[0021] The method for improving the viscosity of caramel pigment of the present invention will be further described below through specific examples.
[0022] Example 1
[0023] The first embodiment of the method for increasing the viscosity of caramel pigment of the present invention includes the following steps: Step 11: Prepare a 15m 3 Reaction kettle, put the catalyst and 7.20 m³ of xylose mother liquor into the reaction kettle according to the mass ratio of 15 - 25%, adjust the pH in the reaction kettle to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and at the same time turn on the stirring device of the reaction kettle to stir the liquid material, control the initial stirring speed frequency at 2400 rpm, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 4.20% and sodium metabisulfite with a mass ratio of 9.73%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE ≥80%, and pH is 3.0 - 6.0.
[0024] Step 12: During the browning reaction, adjust the pH not lower than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, and keep the pressure in the reaction kettle at 0.01 - 0.1 MPa.
[0025] Step 13: When the browning reaction time reaches 5 - 6 h and it is monitored that the red index of the liquid material in the reaction kettle reaches the expected value of 5.5, and at this time the reaction kettle temperature > 130 °C, use 0.6 ± 0.05 MPa of compressed air for backwashing for 40 - 60 minutes; after the backwashing ends, if the reaction kettle temperature > 100 °C, then increase the compressed air pressure to 1.0 MPa for backwashing for 10 minutes; after the backwashing ends, if the reaction kettle temperature < 100 °C, then cool down normally until the browning reaction ends.
[0026] Example 2
[0027] The second embodiment of the method for increasing the viscosity of caramel pigment of the present invention includes the following steps: Step 21: Prepare a 15m 3 Reaction kettle, put the catalyst and 5.50 m³ of xylose mother liquor into the reaction kettle according to the mass ratio of 15 - 25%, adjust the pH in the reaction kettle to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and at the same time turn on the stirring device of the reaction kettle to stir the liquid material, control the initial stirring speed at 2400 rpm, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE ≥80%, and pH is 3.0 - 6.0. Step 22: During the browning reaction, adjust the pH not lower than 4.0, control the opening of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, and keep the pressure in the reaction kettle at 0.01 - 0.1 MPa.
[0028] Step 23: When the browning reaction time reaches 6 - 8 hours and the red index of the liquid in the reaction kettle is monitored to reach the expected value of 6.0, and at this time the temperature in the reaction kettle > 130°C, backflush with compressed air at 0.6 ± 0.05 MPa for 20 - 40 minutes; after the backflushing ends, if the temperature in the reaction kettle > 100°C, then increase the compressed air pressure to 1.0 MPa and backflush for 10 minutes; after the backflushing ends, if the temperature in the reaction kettle < 100°C, then cool down normally until the browning reaction ends.
[0029] Example 3
[0030] The third example of the method for increasing the viscosity of caramel pigment in the present invention includes the following steps: Step 31: Prepare a 15m 3 Reaction kettle, put the catalyst and 3.85 m³ of xylose mother liquor into the reaction kettle according to the mass ratio of 15 - 25%, adjust the pH in the reaction kettle to 3.0 - 7.0, set the browning reaction temperature at 100 - 150°C, and at the same time turn on the stirring device of the reaction kettle to stir the liquid, control the initial stirring speed at 2400 rpm, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%, the refractive index of the xylose mother liquor is 70%, the xylose content ≥ 8%, DE ≥ 80%, and pH 3.0 - 6.0.
[0031] Step 32: During the browning reaction, adjust the pH not lower than 4.0, control the opening of the exhaust valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the exhaust valve, and keep the pressure in the reaction kettle at 0.01 - 0.1 MPa.
[0032] Step 33: When the browning reaction time reaches 8 - 10 hours and the red index of the liquid in the reaction kettle is monitored to reach the expected value of 6.5, and at this time the temperature in the reaction kettle > 130°C, backflush with compressed air at 0.8 ± 0.05 MPa for 20 - 30 minutes; after the backflushing ends, if the temperature in the reaction kettle > 100°C, then increase the compressed air pressure to 1.0 MPa and backflush for 20 minutes; after the backflushing ends, if the temperature in the reaction kettle < 100°C, then cool down normally until the browning reaction ends.
[0033] Comparative Example 1 The first comparative example of the present invention includes the following steps: Step D11: Prepare a 15m 3Reactor, put the catalyst and 7.03 m³ of xylose mother liquor into the reactor according to a mass ratio of 15 - 25%, adjust the pH in the reactor to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 4.10% and sodium metabisulfite with a mass ratio of 9.80%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE ≥80%, and pH is 3.0 - 6.0.
[0034] Step D12: During the browning reaction, adjust the pH not lower than 4.0, control the opening degree of the tail gas valve of the reactor, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reactor at 0.01 - 0.1 MPa.
[0035] Step D13: When the browning reaction time reaches 5 - 6 h, let the materials in the reactor cool down to the normal temperature naturally, and the browning reaction ends.
[0036] Comparative Example 2 The second comparative example of the present invention, this comparative example includes the following steps: Step D21: Prepare 15 m 3 Reactor, put the catalyst and 5.50 m³ of xylose mother liquor into the reactor according to a mass ratio of 15 - 25%, adjust the pH in the reactor to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE ≥80%, and pH is 3.0 - 6.0.
[0037] Step D22: During the browning reaction, adjust the pH not lower than 4.0, control the opening degree of the tail gas valve of the reactor, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reactor at 0.01 - 0.1 MPa.
[0038] Step D23: When the browning reaction time reaches 6 - 8 h, let the materials in the reactor cool down to the normal temperature naturally, and the browning reaction ends.
[0039] Comparative Example 3 The second comparative example of the present invention, this comparative example includes the following steps: Step D31: Prepare 15 m 3Reactor: The catalyst and 7.20 m³ of xylose mother liquor are put into the reactor according to a mass ratio of 15 - 25%. Adjust the pH in the reactor to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 4.20% and sodium metabisulfite with a mass ratio of 11.96%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE ≥80%, and pH is 3.0 - 6.0.
[0040] Step D32: During the browning reaction, adjust the pH to not less than 4.0, control the opening of the tail gas valve of the reactor, and the waste gas generated during the browning reaction is discharged through the tail gas valve to keep the pressure in the reactor at 0.01 - 0.1 MPa.
[0041] Step D33: When the browning reaction time reaches 8 - 10 h, let the materials in the reactor cool naturally to the normal temperature, and the browning reaction ends.
[0042] The red index, pigment, and viscosity indexes of the caramel pigment products obtained in Examples 1 - 3 and Comparative Examples 1 - 3 are detected respectively, and Table 1 is obtained.
[0043] Table 1 Comparison table of performance indexes of caramel pigment products obtained in Examples 1 - 3 and Comparative Examples 1 - 3
[0044] It can be found from Table 1 that the viscosity of the caramel pigment products obtained in Examples 1 - 3 is higher than that in Comparative Examples 1 - 3, indicating that the method for increasing the viscosity of caramel pigment of the present invention can effectively improve the viscosity of the caramel pigment finished product.
[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for increasing the viscosity of caramel pigment, characterized in that, It includes the following steps: Step 1. Put the catalyst and the xylose mother liquor with a volume of 3.85 - 7.20 m 3 into the reaction kettle according to a mass ratio of 15 - 25%. Adjust the pH in the reaction kettle to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and at the same time turn on the stirring device of the reaction kettle to stir the feed liquid to start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 3.15 - 4.20% and sodium metabisulfite with a mass ratio of 9.73 - 13.69%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0 - 6.0; Step 2: During the browning reaction, adjust the pH to not less than 4.0, control the opening degree of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reaction kettle at 0.01 - 0.1 MPa; Step 3: The browning reaction time is 5 - 10 h. At the end of the browning reaction, when it is monitored that the red index of the liquid in the reaction kettle reaches the expected value of 5.5 - 6.5, use compressed air to blow back into the reaction kettle until the browning reaction ends.
2. The method for increasing the viscosity of caramel pigment according to claim 1, wherein It includes the following steps: Step 11. Prepare a 15 m 3 reactor, and put the catalyst and 7.20 m 3 xylose mother liquor into the reactor according to a mass ratio of 15 - 25%. Adjust the pH in the reactor to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and at the same time turn on the stirring device of the reactor to stir the feed liquid to start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 4.20% and sodium metabisulfite with a mass ratio of 9.73%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0 - 6.0; Step 12: During the browning reaction, adjust the pH to not less than 4.0, control the opening degree of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reaction kettle at 0.01 - 0.1 MPa; Step 13: When the browning reaction time reaches 5 - 6 h and it is monitored that the red index of the liquid in the reaction kettle reaches the expected value of 5.5, and at this time the temperature of the reaction kettle > 130 °C, blow back with compressed air at 0.6 ± 0.05 MPa for 40 - 60 minutes; after the blow - back ends, if the temperature of the reaction kettle > 100 °C, then increase the compressed air pressure to 1.0 MPa and blow back for 10 minutes; after the blow - back ends, if the temperature of the reaction kettle < 100 °C, then cool down normally until the browning reaction ends.
3. The method for increasing the viscosity of caramel pigment according to claim 1, wherein, It includes the following steps: Step 21. Prepare a 15 m 3 reactor, and put the catalyst and 5.50 m 3 xylose mother liquor into the reactor according to a mass ratio of 15 - 25%. Adjust the pH in the reactor to 3.0 - 7.0, set the browning reaction temperature at 100 - 150 °C, and at the same time, turn on the stirring device of the reactor to stir the liquid material to start the browning reaction. Among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0 - 6.0; Step 22: During the browning reaction, adjust the pH to not less than 4.0, control the opening degree of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reaction kettle at 0.01 - 0.1 MPa; Step 23: When the browning reaction time reaches 6 - 8 h and it is monitored that the red index of the liquid in the reaction kettle reaches the expected value of 6.0, and at this time the temperature of the reaction kettle > 130 °C, blow back with compressed air at 0.6 ± 0.05 MPa for 20 - 40 minutes; after the blow - back ends, if the temperature of the reaction kettle > 100 °C, then increase the compressed air pressure to 1.0 MPa and blow back for 10 minutes; after the blow - back ends, if the temperature of the reaction kettle < 100 °C, then cool down normally until the browning reaction ends.
4. The method for increasing the viscosity of caramel pigment according to claim 1, wherein It includes the following steps: Step 31. Prepare a 15 m 3 reactor, and put the catalyst and 3.85 m 3 of xylose mother liquor into the reactor according to a mass ratio of 15-25%. Adjust the pH in the reactor to 3.0-7.0, set the browning reaction temperature at 100-150 °C, and at the same time turn on the stirring device of the reactor to stir the liquid material, and start the browning reaction; among them, the catalyst is ammonium sulfite with a mass ratio of 3.15% and sodium metabisulfite with a mass ratio of 13.69%. The refractive index of the xylose mother liquor is 70%, the xylose content is ≥8%, DE≥80%, and pH is 3.0-6.0; Step 32: During the browning reaction, adjust the pH to not less than 4.0, control the opening degree of the tail gas valve of the reaction kettle, and the waste gas generated during the browning reaction is discharged through the tail gas valve, keeping the pressure in the reaction kettle at 0.01 - 0.1 MPa; Step 33: When the browning reaction time reaches 8 - 10 h and it is monitored that the red index of the liquid in the reaction kettle reaches the expected value of 6.5, and at this time the temperature of the reaction kettle > 130 °C, blow back with compressed air at 0.8 ± 0.05 MPa for 20 - 30 minutes; after the blow - back ends, if the temperature of the reaction kettle > 100 °C, then increase the compressed air pressure to 1.0 MPa and blow back for 20 minutes; after the blow - back ends, if the temperature of the reaction kettle < 100 °C, then cool down normally until the browning reaction ends.