Optimized preparation process of culture medium of low-calcium xanthan gum

Abstract

The invention relates to the technical field of culture medium optimization, in particular to a low-calcium xanthan gum culture medium optimization preparation process, which comprises the following steps: adding a double chelating agent HBED, gamma-polyglutamic acid and nano silicon dioxide into a culture medium, and carrying out microwave pretreatment; fermenting by using the modified strain, carrying out three-section speed control by using an airlift tank, and carrying out on-line monitoring and feeding; the fermentation liquor is subjected to ultrasonic treatment in combination with compound enzyme treatment, isopropanol precipitation, spray drying and supercritical desolvation, and composite modification can also be carried out on nano cellulose. The process reduces calcium from the source, reduces the calcium ion content of xanthan gum, improves the utilization rate of a carbon source, and increases the yield; purification is green and efficient, the product purity exceeds 98%, the application scene is expanded, and economic and environment-friendly benefits are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of culture medium optimization, in particular to a culture medium optimization preparation process of low-calcium xanthan gum. BACKGROUND

[0002] Xanthan gum, an extracellular polysaccharide produced by Xanthomonas campestris, is widely used in food, petroleum, medicine, cosmetics and other fields due to its excellent thickening, suspending, emulsifying and temperature and salt tolerance. In practical application, the calcium ion content in xanthan gum has a significant impact on its performance. The xanthan gum prepared by traditional process often contains high concentration of calcium ions. These calcium ions form cross-linked structures with the carboxyl groups in the xanthan gum molecules, which not only enhances the gel properties of the solution to some extent, but also leads to poor flowability and slow dissolution rate of the xanthan gum, and easily causes precipitation in acidic environment or in the presence of other multivalent cations, limiting its application in high-end fields.

[0003] Currently, the methods for reducing the calcium ion content in xanthan gum mainly include adding calcium chelating agents after fermentation or using ion exchange resins for decalcification. However, these methods have obvious defects. Decalcification after fermentation requires additional processing steps and equipment, which not only increases production costs, but also may cause product purity to decrease due to the introduction of a large amount of chemical reagents, and even harmful substances may be left to affect application safety. In addition, post-treatment decalcification cannot reduce the combination of calcium ions and xanthan gum from the root during the fermentation process, making it difficult to achieve efficient preparation of low-calcium xanthan gum.

[0004] In terms of fermentation process, there is also room for optimization in traditional medium formula and fermentation conditions. The proportion of nutritional ingredients in the commonly used medium often cannot accurately match the needs of strain growth and xanthan gum synthesis, resulting in low carbon source utilization efficiency, long fermentation period and low xanthan gum yield. At the same time, the fermentation process often uses constant parameter control, lacks real-time monitoring and precise control of the dynamic changes of bacterial metabolism, and cannot effectively improve the quality and yield of xanthan gum. Moreover, the traditional separation and purification process relies on a large amount of organic solvents, which has high energy consumption, serious pollution and product activity damage, etc., and cannot meet the requirements of green production and high-quality products. With the increasing demand for low-calcium, high-purity and high-performance xanthan gum in food, medicine and other industries, it is urgent to develop a whole-process innovative preparation process from medium optimization to fermentation regulation to separation and purification, in order to realize the efficient, green and high-quality production of low-calcium xanthan gum. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a culture medium optimization preparation process of low-calcium xanthan gum.

[0006] A culture medium optimization preparation process of low-calcium xanthan gum, comprising the following steps: S1: glucose 22-28 g / L, yeast extract 6-9 g / L, potassium dihydrogen phosphate 2.5-3.5 g / L, magnesium sulfate heptahydrate 0.8-1.2 g / L, complex trace element solution 6-9 mL / L; the complex trace element solution is composed of manganese sulfate, zinc sulfate, copper sulfate and sodium molybdate with a mass ratio of 3:1.5:1.2:0.8; 0.15-0.25 g / L of a new calcium chelator N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) is added, and 0.05-0.15 g / L of γ-polyglutamic acid (γ-PGA) is added, and a synergistic reaction occurs , , to form a double chelation system; 0.3-0.6 g / L of nano-silicon dioxide is added at the same time; the structural formula of the N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid is: , S2: seed culture, inoculate the genetically engineered high-osmotic-pressure-resistant Xanthomonas campestris into a seed culture medium, and culture at 29-31°C and 200-220 rpm for 20-22 hours, with an inoculation amount of 4-5%; the genetically engineered gene is a gene overexpressing trehalose synthetase; S3: fermentation culture, inoculate the seed liquid into a fermentation culture medium, use a gas-lift fermenter, set the aeration rate to 1.0-1.2vvm, set the three-stage stirring speed, set the temperature to 28-30°C, and control the pH value at 6.8-7.2 by flowing 25-30% ammonium bicarbonate solution and dilute sulfuric acid; during the fermentation process, real-time monitoring of glucose and xanthan gum concentrations is performed through online near-infrared spectroscopy, and when the glucose concentration decreases to 5 g / L, a mixed solution containing 15-20 g / L glucose and 0.5-1 g / L potassium phosphate dibasic is supplemented; S4: fermentation broth treatment, after the fermentation is completed, first perform ultrasonic treatment at 45-50°C to destroy the cell structure; then add 0.6-0.9% of a composite enzyme based on the volume of the fermentation broth, and treat at 52-58°C for 2.5-3.5 hours; S5: xanthan gum separation and purification, add 2.2-2.8 times the volume of isopropyl alcohol to the treated fermentation broth for precipitation, and centrifugally separate; wash the precipitate with 75-85% ethanol for 2-3 times, then perform spray drying, and remove residual solvents through supercritical carbon dioxide fluid.

[0007] Preferably, after the S1 culture medium is prepared, microwave pretreatment is performed, and the power is 400-600W for 3-5 minutes.

[0008] Preferably, during the S3 fermentation culture stage, blue light with a wavelength of 400-450 nm is introduced into the top of the fermenter, the light intensity of the blue light is 50-80 μmol / m²・s, and the blue light is irradiated for 6-8 hours per day.

[0009] Preferably, the molecular weight of the gamma-polyglutamic acid in the S1 is 500-800 thousand Da, and the specific surface area of the nanometer silicon dioxide is 600-800 m² / g.

[0010] Preferably, the seed culture medium in the S2 contains 0.2-0.4 g / L betaine.

[0011] Preferably, the feeding rate of the ammonium bicarbonate solution in the S3 is automatically adjusted by a pH-feedback control system, and the control accuracy is ±0.05.

[0012] Preferably, the frequency of the ultrasonic treatment in the S4 is 35-45 kHz.

[0013] Preferably, the compound enzyme in the S4 is a protease: amylase: cellulase: lysozyme = 3:1.5:1:0.5.

[0014] Preferably, the pressure of the supercritical carbon dioxide fluid treatment in the S5 is 15-20 MPa, the temperature is 35-40℃, and the treatment time is 30-45 minutes.

[0015] Preferably, the final product is further subjected to nanocellulose composite treatment, low-calcium xanthan gum is prepared into a 3-5% aqueous solution, 0.1-0.3% nanocellulose whiskers are added, high-speed dispersion is performed at 6000-8000 rpm for 10-15 minutes, and the composite modified product is obtained after spray drying, wherein the nanocellulose whiskers have a length of 100-300 nm and a diameter of 10-20 nm.

[0016] Compared with the prior art, the present application has the following beneficial effects: 1. In the medium design, a new type of double chelation system (HBED and gamma-polyglutamic acid synergistic effect) is used to reduce the combination of calcium ions and xanthan gum from the source of fermentation, so that the calcium ion content of the product is reduced, the solubility and flowability of the xanthan gum are effectively improved, the mass transfer efficiency is enhanced by adding nanometer silicon dioxide, the nutritional ingredients are activated by microwave pretreatment, the carbon source utilization rate is improved, and the fermentation period is shortened.

[0017] 2. In the fermentation regulation, the xanthan gum synthesis path is directionally regulated by using a genetically engineered strain and blue light induction technology, three-stage stirring, online near-infrared monitoring, and a precise feeding system are combined to improve the yield of xanthan gum and make the product molecular structure more uniform. In the fermentation liquid treatment stage, the ultrasonic and compound enzyme synergistic effect has a cell breakage rate of over 90%, and the impurity degradation is more thorough, laying a foundation for subsequent purification.

[0018] 3. The separation and purification link adopts isopropanol precipitation instead of ethanol, cooperates with supercritical carbon dioxide fluid desolventizing technology, reduces the use amount of organic solvent, reduces energy consumption, avoids the damage of high temperature to the activity of xanthan gum, and the product purity reaches more than 98%. In addition, the newly added nanocellulose composite treatment step gives the product better thickening property and stability, and expands the application scene of the product in the high-end food and medicine fields. The whole process realizes the green, efficient and high-quality preparation of low-calcium xanthan gum, and has significant economic value and environmental protection benefits. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 is a low-calcium xanthan gum culture medium optimization preparation process flowchart proposed by the application; Fig. 2 is a wear resistance frequency and glossiness fold line comparison chart of the examples and the comparative examples; Fig. 3 is a pollution resistance grade and touch feeling score columnar comparison chart of the examples and the comparative examples; Fig. 4 is a radar comparison chart of the key performance data of the examples and the comparative examples after being unified dimension. DETAILED DESCRIPTION

[0020] According to Figs. 1 to 4 , the specific embodiments of the application are as follows: Example 1: High-gloss skin-feeling coating paper composite process S1: substrate pretreatment A decorative base paper with a basis weight of 180 g / m² is selected and sent to a low-temperature plasma treatment device. The helium flow rate is set to 20 L / min, the oxygen flow rate is set to 6.7 L / min, the power is set to 15 kW, the gas pressure is set to 65 Pa, and the treatment time is set to 5 s. After treatment, the surface tension is detected to be 52 mN / m using a surface tension test pen. The surface is observed by scanning electron microscopy to form nanoscale grooves with an average depth of 40 nm. Then, ultrasonic atomization pretreatment is performed, and 0.5% nanometer titanium dioxide dispersion liquid (particle size 15 nm) is sprayed through an ultrasonic atomizer (frequency 50 kHz), with a spraying amount of 4 g / m². After drying, it is ready for use.

[0021] S2: preparation and coating of primer solution Take 50 parts of thiol-modified polyurethane acrylate oligomer (double bond content 4.2 mmol / g), 30 parts of nano-silica aerogel (particle size 20 nm, specific surface area 800 m² / g), 20 parts of γ-methacryloxypropyltrimethoxysilane, 10 parts of photoinitiator 184, 1.2 parts of dopamine-nanocellulose composite (dopamine 2 g / L, nanocellulose 1 g / L) and 1.0% of nano-silver particles (particle size 20 nm) by mass ratio. Stir with a high-speed disperser at 3000 rpm for 40 min, and ultrasonic defoaming for 20 min. Coating with a gravure printing machine with 180 lines / inch, coating amount 11 g / m², drying in a 90°C hot air circulation oven for 7 min.

[0022] S3: Preparation of middle coating Take 60 parts of water-based polyurethane dispersion (solid content 40%, molecular weight 40000), 40 parts of carbon nanotube forest (height 6 μm, tube diameter 15 nm), 20 parts of nanoscale mica powder (aspect ratio 80:1), 10 parts of phase change microcapsules (octadecane core material, particle size 8 μm, phase change latent heat 200 J / g), and 1.5 parts of film-forming aid dipropylene glycol butyl ether by mass ratio. Grind with a three-roll mill to a fineness of ≤15 μm. Use a reverse roll coater, coating amount 20 g / m², dry in an infrared drying oven at 140°C for 15 min. Immediately after coating, apply an alternating magnetic field of 0.9T and 20Hz for 6 min.

[0023] S4: Preparation and coating of skin-feel topcoat Take 70 parts of fluorine-containing acrylate-siloxane block copolymer (fluorine content 12%, siloxane segment 30%), 30 parts of hyperbranched polyether amine modified polyester resin (branching degree 0.7), 20 parts of nanoscale titanium dioxide (particle size 30 nm), 10 parts of silicone-modified polytetrafluoroethylene slip agent, and 0.8 parts of photochromic spiropyran dye (maximum absorption wavelength 340 nm) by mass ratio. Emulsify with a high-shear emulsifier at 5000 rpm for 30 min. Coating by micro-embossing roller, coating amount 9 g / m², curing in a UV-LED curing device in three stages: first stage 450 mJ / cm², second stage 400 mJ / cm², third stage 350 mJ / cm².

[0024] S5: Composite pressing A medium density fiberboard (MDF) with a thickness of 18 mm and a surface roughness Ra of 1.0 μm was selected. A 100 nm thick silicon dioxide transition layer was formed on the surface of the substrate by chemical vapor deposition. The coating paper and the substrate were placed in a vacuum hot press compounding machine, with a temperature of 95°C, a pressure of 7 MPa, a vacuum degree of -0.07 MPa, and a pressure maintaining time of 22 s. Subsequently, hot steam with a humidity of 90% and a temperature of 80°C was introduced for 4 min. After pressing, ultraviolet ozone treatment was performed at a wavelength of 254 nm, an ozone concentration of 15 mg / m³, and a treatment time of 10 min.

[0025] Example 2: Matt skin-coated paper compounding process S1: Substrate pretreatment A decorative base paper with a basis weight of 200 g / m² was selected and sent to a low-temperature plasma treatment device. The helium flow rate was set to 22 L / min, the oxygen flow rate was set to 7.3 L / min, the power was set to 16 kW, the gas pressure was set to 70 Pa, and the treatment time was set to 4.5 s. After treatment, the surface tension reached 53 mN / m, and a nanoscale groove with an average depth of 35 nm was formed on the surface. Subsequently, ultrasonic atomization pretreatment was performed, and 0.5% of a nanometer titanium dioxide dispersion solution (particle size 15 nm) was sprayed through an ultrasonic atomizer with a frequency of 50 kHz, with a spraying amount of 4 g / m². After drying, it was ready for use.

[0026] S2: Preparation and coating of the primer 55 parts of a thiol-modified polyurethane acrylate oligomer (double bond content 4.5 mmol / g), 25 parts of nanometer-sized silica aerogel (particle size 25 nm, specific surface area 800 m² / g), 25 parts of γ-methacryloxypropyltrimethoxysilane, 12 parts of photoinitiator 184, 1.5 parts of dopamine-nanocellulose composite (dopamine 2.5 g / L, nanocellulose 1.2 g / L), and 1.2% of nanometer-sized silver particles were weighed according to the mass ratio. After high-speed dispersion for 40 min at 3000 rpm and ultrasonic debubbling for 20 min, the coating was applied using a 180 line / inch screen roller gravure printing machine, with a coating amount of 12 g / m² and drying at 92°C for 8 min.

[0027] S3: Preparation of the intermediate coating 65 parts of a water-based polyurethane dispersion (solid content 42%, molecular weight 45000), 35 parts of carbon nanotube forest (height 7 μm), 25 parts of nanometer-sized mica powder (aspect ratio 80:1), 12 parts of phase change microcapsules (octadecane core material, particle size 9 μm, phase change latent heat 200 J / g), and 1.7 parts of a film-forming aid, dipropylene glycol butyl ether, were weighed according to the mass ratio. After three-roll milling to a fineness of ≤15 μm, the coating was applied using an inverse roll coater at a coating amount of 21 g / m², and dried at 145°C for 16 min using infrared drying. Immediately after, an alternating magnetic field with a strength of 1.0 T and a frequency of 22 Hz was applied for 7 min.

[0028] S4: Preparation and coating of skin-feeling topcoat 75 parts of fluorine-containing acrylate-silicone block copolymer (fluorine content 13%, siloxane segment 32%), 25 parts of hyperbranched polyester resin, 22 parts of nano-sized titanium dioxide (particle size 35 nm), 12 parts of slip agent, and 1.0 part of photochromic spiropyran dye were weighed according to the mass ratio. After high-shear emulsification for 30 min at 5000 rpm, micro-concave roller coating was performed at 9 g / m², and UV-LED three-stage curing was performed (first stage 500 mJ / cm², second stage 450 mJ / cm², and third stage 380 mJ / cm²).

[0029] S5: Composite pressing A 16 mm high-density fiberboard was selected, and a 110 nm silica transition layer was deposited on the surface. The vacuum hot pressing composite conditions were as follows: temperature 100°C, pressure 8 MPa, vacuum degree -0.065 MPa, pressure maintaining time 25 s; then, 92% humidity, 80°C hot steam treatment for 5 min, and then 185 nm wavelength, 18 mg / m³ concentration of ultraviolet ozone treatment for 11 min.

[0030] Example 3: Antibacterial skin-feeling coated paper composite process S1: Substrate pretreatment A 180 g / m² decorative base paper was selected, and the low-temperature plasma treatment parameters were as follows: helium 20 L / min, oxygen 6.7 L / min, power 15 kW, gas pressure 65 Pa, and treatment time 5 s. The surface tension reached 52 mN / m, and 40 nm deep nanoscale grooves were formed. The ultrasonic atomization pretreatment was the same as before: 0.5% nanoscale titanium dioxide dispersion (15 nm particle size), 50 kHz ultrasonic spraying 4 g / m², and drying for standby.

[0031] S2: Preparation and coating of primer In the basic formula of 50 parts of thiol-modified polyurethane acrylate oligomer (4.2 mmol / g double bond), 30 parts of nanoscale silica aerogel (20 nm particle size, 800 m² / g specific surface area), 20 parts of silane coupling agent, and 10 parts of photoinitiator 184, the amount of nanosilver particles was increased to 1.5%, and 1.2 parts of dopamine-nanocellulose composite (dopamine 2 g / L, nanocellulose 1 g / L) was added. After 40 min of dispersion at 3000 rpm and 20 min of ultrasonic debubbling, 10 g / m² was coated by gravure printing, and dried at 88°C for 6.5 min.

[0032] S3: Preparation of intermediate coating Take 60 parts of waterborne polyurethane dispersion (40% solid content, 40000 molecular weight), 40 parts of carbon nanotube forest (6 μm height, 15 nm tube diameter), 20 parts of nanometer mica powder (80:1 aspect ratio), 10 parts of phase change microcapsule (8 μm particle size, 200 J / g latent heat), add 1.5 parts of dipropylene glycol butyl ether film forming agent, and three roll mill to ≤15 μm. Reverse roll coating 20 g / m², 140°C infrared drying 15 min, omitting magnetic field treatment.

[0033] S4: Skin feel topcoat preparation and coating Take 80 parts of fluorine-containing acrylate-siloxane block copolymer (14% fluorine content), 20 parts of hyperbranched polyester resin, 25 parts of nanometer titanium dioxide (38 nm particle size), 15 parts of slip agent by mass ratio, add 0.6 parts of photochromic spiropyran dye. After emulsification at 5000 rpm for 30 min, micro-concave roller coating 8 g / m², UV-LED three-stage curing total energy 1200 mJ / cm².

[0034] S5: Composite pressing Select 12 mm plywood, deposit 90 nm silica transition layer on the surface. Vacuum hot pressing conditions: temperature 88°C, pressure 6.5 MPa, vacuum degree -0.075 MPa, pressure maintaining 20 s; humidification 88%, 80°C hot steam treatment for 3.5 min, and then 254 nm wavelength, 12 mg / m³ concentration ultraviolet ozone treatment for 9 min.

[0035] Comparative example: traditional skin feel paper composite process Substrate treatment: select 180 g / m² decorative base paper, only 8 kW power corona treatment, surface tension up to 38 mN / m.

[0036] Primer: use ordinary polyurethane primer, anilox roll coating 15 g / m², 100°C drying 10 min.

[0037] Middle coating: add ordinary matting powder to waterborne acrylic paint, reverse roll coating 25 g / m², 130°C drying 20 min.

[0038] Topcoat: ordinary UV skin feel coating micro-concave roller coating 12 g / m², 800 mJ / cm² one-time UV curing.

[0039] Composite: hot pressing temperature 120°C, pressure 3 MPa, no steam and ultraviolet ozone treatment.

[0040] Comparison of key properties of examples and comparative examples as follows: Table 1 , Comparison of coating structure and performance parameters of examples as follows: Table 2 .

[0041] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since numerous changes, modifications, substitutions and variations can be made thereto without departing from the spirit and scope of the application as defined by the appended claims and their equivalents.

Claims

1. A culture medium optimization preparation process for low-calcium xanthan gum, characterized in that: The following steps are involved: S1: Weigh 22-28 g / L of glucose, 6-9 g / L of yeast extract, 2.5-3.5 g / L of potassium dihydrogen phosphate, 0.8-1.2 g / L of magnesium sulfate heptahydrate, and 6-9 mL / L of a complex trace element solution, each containing manganese sulfate, zinc sulfate, copper sulfate, and sodium molybdate in a mass ratio of 3:1.5:1.2:0.

8. Add 0.15-0.25 g / L of a new calcium chelator, N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), and 0.05-0.15 g / L of γ-polyglutamic acid (γ-PGA), to produce a synergistic reaction. ， ， A double chelate system is formed; 0.3-0.6 g / L of nano-silica is added at the same time; the structural formula of the N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid is: ， S2: Seed culture, inoculating a genetically engineered high osmotic pressure-tolerant Xanthomonas campestris into a seed culture medium, culturing at 29-31°C and 200-220 rpm for 20-22 hours, with an inoculum size of 4-5%; the genetically engineered gene is an overexpressed trehalose synthase gene; S3: Fermentation culture: The seed liquid was inoculated into the fermentation medium in an airlift fermenter with an aeration rate of 1.0-1.2 vvm, a three-stage stirring speed, and a temperature of 28-30°C. The pH value was controlled at 6.8-7.2 by feeding 25-30% ammonium bicarbonate solution and dilute sulfuric acid. During the fermentation process, the concentrations of glucose and xanthan gum were monitored in real time by online near-infrared spectroscopy. When the glucose concentration dropped to 5 g / L, a mixed solution containing 15-20 g / L glucose and 0.5-1 g / L potassium hydrogen phosphate was added. S4: Fermentation broth treatment: After fermentation, perform ultrasonic treatment at 45-50°C to destroy the cell structure; then add 0.6-0.9% of the fermentation broth volume of the complex enzyme and treat at 52-58°C for 2.5-3.5 hours; S5: Xanthan gum is isolated and purified by adding 2.2-2.8 times the volume of isopropanol to the treated fermentation broth for precipitation and centrifugation; the precipitate is washed 2-3 times with 75-85% ethanol, then spray-dried, and the residual solvent is removed by supercritical carbon dioxide fluid.

2. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The method further includes performing microwave pretreatment at a power of 400-600W for 3-5 minutes after the S1 culture medium is prepared.

3. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The method further includes introducing blue light with a wavelength of 400-450 nm into the top of the fermentation tank during the S3 fermentation culture stage for 6-8 hours per day, wherein the light intensity of the blue light is 50-80 μmol / m²·s.

4. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The molecular weight of the γ-polyglutamic acid in S1 is 500,000-800,000 Da, and the specific surface area of ​​the nano-silica is 600-800 m² / g.

5. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The seed culture medium in S2 contains 0.2-0.4 g / L betaine.

6. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The flow rate of the ammonium bicarbonate solution in S3 is automatically adjusted by a pH-feedback control system with a control accuracy of ±0.

05.

7. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The frequency of the ultrasonic treatment in S4 is 35-45 kHz.

8. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The complex enzyme in S4 is protease: amylase: cellulase: lysozyme = 3:1.5:1:0.

5.

9. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, wherein The supercritical carbon dioxide fluid treatment in S5 is performed at a pressure of 15-20 MPa, a temperature of 35-40° C., and a treatment time of 30-45 minutes.

10. The culture medium optimization preparation process of low-calcium xanthan gum according to claim 1, characterized in that, The method also includes subjecting the final product to nanocellulose composite treatment, preparing low-calcium xanthan gum into a 3-5% aqueous solution, adding 0.1-0.3% nanocellulose whiskers, dispersing at a high speed of 6000-8000 rpm for 10-15 minutes, and spray drying to obtain a composite modified product, wherein the nanocellulose whiskers have a length of 100-300 nm and a diameter of 10-20 nm.

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