A kind of low pyruvate xanthan gum and preparation method thereof

Abstract

The invention relates to the technical field of microbial fermentation, and specifically discloses a low-pyruvate xanthan gum and a preparation method thereof. The preparation method of the low-pyruvate xanthan gum comprises the following steps: S1, after activating xanthomonas by using an activation culture medium, transferring the activated strain into a seed culture medium for cultivation to obtain a seed liquid, inoculating the seed liquid into a fermentation culture medium, and obtaining a fermentation liquid after the cultivation is completed; S2, adding a treatment agent to the fermentation liquid obtained in step S1, stirring it, heating it to obtain a treatment liquid, extracting it with ethanol after cooling, drying it, and crushing it to obtain the treated liquid; the obtained low-pyruvate xanthan gum has excellent synergy, high temperature resistance, acid resistance, salt resistance and other properties, and has good product stability; the culture medium of the invention has simple components, a simple preparation method, saves time compared with mutating strains and improving strains, saves cost compared with optimizing culture medium components and adjusting culture control conditions, and is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of microbial fermentation, and more specifically, to low-pyruvate xanthan gum and a preparation method thereof. Background Art

[0002] Xanthan gum, also known as yellow gum or xanthan gum, has a molecular weight of 2 to 6 million and is a light yellow to white flowable powder. Xanthan gum is an extracellular acidic heteropolysaccharide produced by fermentation of Xanthomonas campestris. It is a high molecular microbial polymer obtained by fermentation, ethanol extraction, drying and crushing of carbohydrates as the main raw material. It is composed of glucose, mannose, glucuronic acid, acetic acid and pyruvic acid. Xanthan gum is a new type of polysaccharide fermentation product. It is currently widely used in more than 20 industries such as petroleum, mining, food, medicine, and textiles.

[0003] Xanthan gum has unique physical and chemical properties, integrating thickening, suspension and emulsification stabilization functions, mainly manifested in outstanding high viscosity and water solubility, unique rheological properties, excellent temperature stability, pH stability, safety, etc. With the continuous expansion of application fields, higher requirements are put forward for the properties of xanthan gum. For example, in the food industry, the requirements for the synergy and temperature and salt resistance of xanthan gum are getting higher and higher. Although traditional xanthan gum has good compatibility, it is prone to oxidative degradation and hydrolysis at high temperatures, resulting in a rapid decrease in the viscosity of its aqueous solution, thus limiting its application.

[0004] In the xanthan gum molecule, the pyruvate functional group and the acetyl group are located at the end of the side chain, and the number of pyruvate groups in the side chain significantly affects the performance of the xanthan gum. Improving the synergy and temperature and salt resistance of xanthan gum requires changing the pyruvate group in its side chain. In the prior art, microbial fermentation is usually used to change the pyruvate group in the side chain of xanthan gum by improving the strain, optimizing the composition of the culture medium, and controlling the culture conditions. However, the existing methods have limited means of regulating the pyruvate group in the side chain of xanthan gum, and it is difficult to effectively improve its synergy and temperature and salt resistance; and the process of improving the strain and optimizing the culture conditions is complicated and costly, which limits the commercial application of low pyruvate xanthan gum; the obtained xanthan gum is easily degraded under high temperature or extreme environmental conditions, and the product is unstable, which affects its reliability in practical applications. Based on the above statements, the present invention provides a low pyruvate xanthan gum and a preparation method thereof. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a low-pyruvate xanthan gum and a preparation method thereof.

[0006] In the first aspect, the present invention provides a method for preparing low-pyruvate xanthan gum, which adopts the following technical scheme:

[0007] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0008] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, the seed liquid is inoculated into a fermentation medium, and a fermentation liquid is obtained after the cultivation is completed;

[0009] S2. Add the treating agent to the fermentation liquid obtained in step S1, stir it, heat it to 100-120° C. and keep it for 10-20 min to obtain a treated liquid, and then extract it with ethanol, dry it, and grind it to obtain low pyruvate xanthan gum.

[0010] Preferably, the activation culture medium components in step S1 include: 18-24 g / L malt extract, 8-12 g / L white sugar, 8-12 g / L peptone, 12-18 g / L agar, pH 6.4-6.8; the activation culture conditions are: culture at 27-32°C, 150-180 r / min constant temperature shaking incubator for 36-48 hours.

[0011] Preferably, the seed culture medium components in step S1 include: 10-15 g / L white sugar, 8-12 g / L peptone, 8-12 g / L beef extract, 1-3 g / L ammonium citrate, 20-25 g / L glucose, pH 6.5-7.0; the seed culture conditions are: culture at 27-32° C., 150-180 r / min constant temperature shaker for 20-24 h.

[0012] Preferably, the fermentation medium components in step S1 include: 28-32 g / L ginger leaf powder, 15-25 g / L starch, 10-15 g / L peptone, pH 6.8-7.2; the fermentation culture conditions are: culture at 28-35° C., 180-220 r / min constant temperature shaking incubator for 50-60 h.

[0013] Preferably, the ginger leaf powder is prepared by the following method: wash fresh ginger leaves and blanch them in boiling water for 1-2 minutes, cut them into small pieces after blanching, dry them at a temperature of 50-60° C., and grind them through a 50-70 mesh sieve to obtain ginger leaf powder.

[0014] Preferably, the treatment agent in step S2 is an organic acid and / or an inorganic salt.

[0015] Preferably, the organic acid is citric acid and / or ferulic acid; and the inorganic salt is magnesium sulfate and / or zinc sulfate.

[0016] Preferably, the treatment agent comprises citric acid and magnesium sulfate in a mass ratio of 3-5:1; the amount of the treatment agent added is 5-10% of the mass of the fermentation broth.

[0017] Preferably, the ethanol extraction in step S2 specifically refers to: extracting the treated liquid with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2-1.5, discarding the ethanol layer liquid, and taking the precipitate.

[0018] In a second aspect, the present invention provides a low-pyruvate xanthan gum, which adopts the following technical solution:

[0019] A low-pyruvate xanthan gum is prepared by the preparation method of the low-pyruvate xanthan gum.

[0020] In summary, the present invention has the following beneficial effects:

[0021] The invention utilizes ginger leaf powder, starch and peptone to co-ferment and cultivate mature fermentation liquid, and then adds a treating agent to the fermentation liquid, performs a temperature-raising heat treatment, and then cools the fermentation liquid for ethanol extraction and pulverization to obtain a low-pyruvate xanthan gum product with excellent synergy, high temperature resistance, acid resistance, salt resistance and other properties. The product has good product stability and broad market prospects. The culture medium of the invention has simple components and a simple preparation method, saves time compared with mutating strains and improving strains, saves cost compared with optimizing culture medium components and adjusting culture control conditions, and is suitable for industrial production.

[0022] The present invention adopts starch as a carbon source and peptone as a nitrogen source, and adds ginger leaf powder rich in protein, vitamins, minerals and other nutrients as a supplementary nutrient component. In addition to providing additional nutritional support for microorganisms, the natural ingredients and bioactive substances contained in the ginger leaf powder can, on the one hand, help the microorganisms resist oxidative stress, improve survival and growth capabilities, promote the growth and reproduction of microorganisms, and improve the rate and efficiency of the fermentation process; on the other hand, the pyruvic acid group of the xanthan gum side chain can be changed, the synthesis of specific metabolites can be promoted, and the yield of the product can be improved. In addition, ginger seedlings, which are waste after ginger is harvested, are used for culture medium addition, which can effectively reduce costs.

[0023] The invention can effectively adjust the pH value of the fermentation liquid by adding a composite treatment agent of organic acid and inorganic salt into the fermentation liquid, help the rupture of the cell membrane, further release the xanthan gum in the cells, and improve the extraction efficiency; the heating treatment can change the solubility of the xanthan gum and promote its release from the cells; the addition of the treatment agent can also effectively reduce the content of acrylic acid in the xanthan gum, and the proportion of pyruvic acid is as low as 1.22%, thereby improving the high temperature resistance, acid resistance, salt resistance and other properties of the xanthan gum. The obtained low pyruvic acid xanthan gum product can withstand a high temperature of 130-140°C and a salt concentration of 30%, has good product stability and a high gum yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a pyruvic acid standard curve diagram for determining the pyruvic acid content in the embodiment of the present invention;

[0025] Figure 2 This is a state diagram of the treatment liquid obtained after adding the treatment agent and heating the treatment in Example 1 and Example 2 of the present invention;

[0026] Figure 3 This is a process state diagram of extracting the treatment liquid with an ethanol solution in Example 1 of the present invention;

[0027] Figure 4 This is a picture of the low pyruvate xanthan gum product obtained in Example 1, Example 2 and Comparative Example 7 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the embodiments.

[0029] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0030] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0031] The ginger leaf powder is prepared by the following method: fresh ginger leaves are washed and blanched in boiling water for 2 minutes, cut into small sections after blanching, dried at 55°C, and crushed through a 60-mesh sieve to obtain ginger leaf powder.

[0032] Embodiment 1-10 provides a low-pyruvate xanthan gum and a preparation method thereof.

[0033] Example 1

[0034] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0035] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0036] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculate Xanthomonas campestris SHBCC D51465 (purchased from Shanghai Collection Biotechnology Center) in the activation medium at an inoculum rate of 1%, culture at 27°C, 150 r / min constant temperature shaker for 48 h, subculture twice, and activate the strain;

[0037] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0038] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0039] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0040] Example 2

[0041] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0042] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0043] S11. The activation medium components include: 21 g / L malt extract, 10 g / L white sugar, 10 g / L peptone, 15 g / L agar, pH 6.6; inoculate Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum rate of 3%, culture at 30°C, 160 r / min constant temperature shaker for 42 hours, subculture twice, and activate the strain;

[0044] S12, seed culture medium components include: white sugar 12g / L, peptone 10g / L, beef extract 10g / L, ammonium citrate 2g / L, glucose 22g / L, pH 6.8; the activated strain was inoculated into the seed culture medium at an inoculum of 3%, and cultured at 30℃, 160r / min constant temperature shaker for 22h, and the OD 600 is 0.6, and the seed solution is obtained;

[0045] S13, the fermentation medium components include: 30g / L ginger leaf powder, 20g / L corn starch, 12g / L peptone, pH7.0; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 9%, and cultured at 30°C, 200r / min constant temperature shaking table for 55h to obtain a fermentation liquid;

[0046] S2. Add 8% of the mass of the fermentation liquid to the fermentation liquid obtained in step S1. Stir at a speed of 400 r / min for 1.5 hours, heat to 110° C. and keep warm for 15 minutes to obtain a treated liquid. After cooling, extract the treated liquid with 95% ethanol solution by volume at a volume ratio of 1:1.4, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate in a mass ratio of 4:1.

[0047] Example 3

[0048] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0049] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0050] S11. The activation medium components include: 24 g / L malt extract, 12 g / L white sugar, 12 g / L peptone, 18 g / L agar, pH 6.8; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum rate of 4%, culturing at 32° C., 180 r / min constant temperature shaking incubator for 36 h, performing two subcultures, and activating the strain;

[0051] S12, seed culture medium components include: 15g / L white sugar, 12g / L peptone, 12g / L beef extract, 3g / L ammonium citrate, 25g / L glucose, pH 7.0; the activated strain was inoculated into the seed culture medium at an inoculum of 4%, and cultured at 32°C, 180r / min constant temperature shaking for 20h, and the OD 600 is 0.7, and the seed solution is obtained;

[0052] S13, the fermentation medium components include: 32g / L ginger leaf powder, 25g / L corn starch, 15g / L peptone, pH7.2; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 11%, and cultured at 35°C, 220r / min constant temperature shaking incubator for 50h to obtain a fermentation liquid;

[0053] S2. Add a treating agent in an amount of 10% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir the mixture at a speed of 500 r / min for 1 hour, heat the mixture to 120° C. and keep the mixture for 10 minutes to obtain a treated liquid. After cooling, extract the treated liquid with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.5, discard the ethanol layer, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent comprises citric acid and magnesium sulfate at a mass ratio of 5:1.

[0054] Example 4

[0055] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0056] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0057] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0058] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0059] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0060] S2. Add a treating agent in an amount of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir the mixture at a speed of 300 r / min for 2 hours, heat the mixture to 100° C. and keep the mixture for 20 minutes to obtain a treated liquid. After cooling, extract the treated liquid with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2, discard the ethanol layer, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent comprises ferulic acid and magnesium sulfate at a mass ratio of 3:1.

[0061] Example 5

[0062] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0063] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0064] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0065] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0066] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0067] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and zinc sulfate at a mass ratio of 3:1.

[0068] Example 6

[0069] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0070] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0071] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0072] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0073] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0074] S2. Add a treating agent in an amount of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir the mixture at a speed of 300 r / min for 2 h, heat the mixture to 120° C. and keep the mixture for 10 min to obtain a treated liquid. After cooling, extract the treated liquid with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2, discard the ethanol layer, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent comprises ferulic acid and zinc sulfate at a mass ratio of 3:1.

[0075] Example 7

[0076] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0077] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0078] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0079] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0080] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0081] S2. Add 5% citric acid by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid. After cooling, extract the treated liquid with 95% ethanol solution by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum.

[0082] Example 8

[0083] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0084] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0085] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0086] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0087] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0088] S2. Add 5% ferulic acid by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid. After cooling, extract the treated liquid with 95% ethanol solution by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum.

[0089] Example 9

[0090] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0091] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0092] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0093] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0094] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0095] S2. Add 5% magnesium sulfate by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid. After cooling, extract the treated liquid with 95% ethanol solution by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum.

[0096] Example 10

[0097] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0098] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0099] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0100] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0101] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0102] S2. Add 5% zinc sulfate by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid. After cooling, extract the treated liquid with 95% ethanol solution by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum.

[0103] In order to verify the comprehensive performance of the low pyruvate xanthan gum prepared in Examples 1-10 of the present invention, the applicant set up Comparative Examples 1-7, which are as follows:

[0104] Comparative Example 1

[0105] The difference between Comparative Example 1 and Example 1 is that the ginger leaf powder in the fermentation medium is replaced by corn starch, as follows:

[0106] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0107] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0108] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0109] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0110] S13, fermentation medium components include: corn starch 43g / L, peptone 10g / L, pH 6.8; seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain fermentation liquid;

[0111] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0112] Comparative Example 2

[0113] The difference between Comparative Example 2 and Example 1 is that the "ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L" in the fermentation medium is replaced by "corn starch 31.8g / L, peptone 21.2g / L", as follows:

[0114] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0115] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0116] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0117] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0118] S13, fermentation medium components include: corn starch 31.8g / L, peptone 21.2g / L, pH 6.8; seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking for 60h to obtain fermentation liquid;

[0119] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0120] Comparative Example 3

[0121] The difference between Comparative Example 3 and Example 1 is that Xanthomonas campestris SHBCC D51465 is replaced by Xanthomonas campestris SHBCC D80768 (purchased from Shanghai Collection Biotechnology Center), as follows:

[0122] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0123] S1. After activating Xanthomonas campestris D80768 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0124] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D80768 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0125] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0126] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0127] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0128] Comparative Example 4

[0129] The difference between Comparative Example 4 and Comparative Example 2 is that Xanthomonas campestris SHBCC D51465 is replaced by Xanthomonas campestris SHBCC D80768, as follows:

[0130] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0131] S1. After activating Xanthomonas campestris D80768 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0132] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D80768 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0133] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0134] S13, fermentation medium components include: corn starch 31.8g / L, peptone 21.2g / L, pH 6.8; seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking for 60h to obtain fermentation liquid;

[0135] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 120° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0136] Comparative Example 5

[0137] The difference between Comparative Example 5 and Example 1 is that a treatment agent is added before fermentation culture, specifically as follows:

[0138] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0139] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0140] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0141] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0142] S13, the fermentation medium components include: 28g / L ginger leaf powder, 15g / L corn starch, 10g / L peptone, pH6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and a treatment agent of 5% of the total mass of the fermentation medium and the seed liquid is added, and the fermentation liquid is cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid, wherein the treatment agent includes citric acid and magnesium sulfate in a mass ratio of 3:1;

[0143] S2. The fermentation liquid obtained in step S1 is stirred at a speed of 300 r / min for 2 hours, and then the temperature is raised to 120° C. and kept warm for 10 minutes to obtain a treated liquid. After cooling, the treated liquid is extracted with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2, the ethanol layer liquid is discarded, and the precipitate is dried at 80° C. and then crushed to obtain low pyruvate xanthan gum.

[0144] Comparative Example 6

[0145] The difference between Comparative Example 6 and Example 1 is that no treating agent is added to the fermentation broth, which is as follows:

[0146] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0147] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0148] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0149] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0150] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0151] S2. The fermentation liquid obtained in step S1 is stirred at a speed of 300 r / min for 2 hours, and then the temperature is raised to 120° C. and kept warm for 10 minutes to obtain a treated liquid. After cooling, the treated liquid is extracted with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2, the ethanol layer liquid is discarded, and the precipitate is dried at 80° C. and then crushed to obtain low pyruvate xanthan gum.

[0152] Comparative Example 7

[0153] The difference between Comparative Example 7 and Example 1 is that the temperature of the heat treatment in step S2 is 90° C., as follows:

[0154] A method for preparing low-pyruvic acid xanthan gum comprises the following steps:

[0155] S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, and the seed liquid is inoculated into a fermentation medium. After the cultivation is completed, a fermentation liquid is obtained. The specific operation is as follows:

[0156] S11. The activation medium components include: 18 g / L malt extract, 8 g / L white sugar, 8 g / L peptone, 12 g / L agar, pH 6.4; inoculating Xanthomonas campestris SHBCC D51465 in the activation medium at an inoculum amount of 1%, culturing at 27°C, 150 r / min constant temperature shaking incubator for 48 hours, subculturing twice, and activating the strain;

[0157] S12, seed culture medium components include: white sugar 10g / L, peptone 8g / L, beef extract 8g / L, ammonium citrate 1g / L, glucose 20g / L, pH 6.5; the activated strain was inoculated into the seed culture medium at an inoculum of 1%, and cultured at 27°C, 150r / min constant temperature shaker for 24h, and the OD 600 is 0.5, and the seed solution is obtained;

[0158] S13, the fermentation medium components include: ginger leaf powder 28g / L, corn starch 15g / L, peptone 10g / L, pH 6.8; the seed liquid is inoculated into the fermentation medium at an inoculum amount of 7%, and cultured at 28°C, 180r / min constant temperature shaking incubator for 60h to obtain a fermentation liquid;

[0159] S2. Add a treating agent of 5% by mass of the fermentation liquid to the fermentation liquid obtained in step S1, stir at a speed of 300 r / min for 2 hours, heat to 90° C. and keep warm for 10 minutes to obtain a treated liquid, and after cooling, extract the treated liquid with an ethanol solution of 95% by volume at a volume ratio of 1:1.2, discard the ethanol layer liquid, take the precipitate, dry it at 80° C., and then crush it to obtain low pyruvate xanthan gum; wherein the treating agent includes citric acid and magnesium sulfate at a mass ratio of 3:1.

[0160] Performance Testing

[0161] The comprehensive properties of the low pyruvic acid xanthan gums prepared in Examples 1-10 of the present invention and Comparative Examples 1-7 were tested respectively, and the specific methods are as follows:

[0162] At room temperature, the low pyruvate xanthan gum was added with deionized water to prepare xanthan gum solutions with a mass concentration of 20 g / L to obtain samples to be tested.

[0163] Determination of pyruvic acid content: Use 2,4-dinitrophenylhydrazine colorimetry to compare with the pyruvic acid standard curve of the same treatment to obtain the pyruvic acid content in the sample. Determine the pyruvic acid content in low pyruvic acid xanthan gum products. The pyruvic acid standard curve is as follows: Figure 1 As shown;

[0164] Viscosity measurement: The viscosity value measured by a viscometer, in cP;

[0165] Determination of xanthan gum yield: The mass of the low-pyruvate xanthan gum obtained in step S2 is divided by the mass of the fermentation liquid in step S1 to obtain the xanthan gum yield. The specific formula is as follows:

[0166] Gum yield (%) = low pyruvate xanthan gum mass (g) / xanthan gum fermentation liquid mass (g) × 100%;

[0167] The results are shown in Table 1.

[0168] Table 1:

[0169]

[0170] Combined with Figure 2-4 As shown in the data in Table 1 above, the comprehensive performance and gum yield of the low pyruvate xanthan gum prepared in Examples 1-10 of the present invention are significantly better than those of Comparative Examples 1-7. The culture medium of the present invention has simple components, a simple preparation method, and a low preparation cost. The obtained low pyruvate xanthan gum has excellent performance and has a broad market prospect. Figure 2 This is a state diagram of the treatment liquid obtained after adding the treatment agent and heating the temperature in Example 1 and Example 2 of the present invention; in the figure, A is the treatment liquid obtained by the treatment in Example 1, and B is the treatment liquid obtained by the treatment in Example 2. Figure 3 This is a process state diagram of extracting the treatment liquid with ethanol solution in Example 1 of the present invention. Figure 4 This is a picture of the low pyruvate xanthan gum product obtained in Example 1, Example 2 and Comparative Example 7 of the present invention; in the picture, from left to right are Comparative Example 7, Example 1 and Example 2.

[0171] Salt tolerance test: Potassium chloride was added to the samples to be tested, and the mass concentration of potassium chloride in the xanthan gum solution was controlled to be 10%, 20%, and 30%, respectively. After stirring until completely dissolved, the solution was stabilized at room temperature for 1 hour, and the viscosity of xanthan gum in the presence of different concentrations of potassium chloride was measured.

[0172] High temperature resistance test: The samples were heated to 130℃ and 140℃ respectively, kept warm for 1h, and then the viscosity of xanthan gum was measured under high temperature conditions;

[0173] The results are shown in Table 2.

[0174] Table 2:

[0175]

[0176] It can be seen from the data shown in Table 2 above that the viscosity variation range of the xanthan gum solution obtained by preparing the low pyruvate xanthan gum prepared in Examples 1-10 of the present invention in the presence of salt or high temperature treatment is significantly lower than that of Comparative Examples 1-7, that is, the low pyruvate xanthan gum prepared in Examples 1-10 of the present invention has excellent high temperature resistance and salt resistance, and the product stability is good.

[0177] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to the embodiment of the present invention as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for preparing low-pyruvate xanthan gum, characterized in that: The following steps are involved: S1. After activating Xanthomonas campestris D51465 using an activation medium, the activated strain is transferred into a seed medium for cultivation to obtain a seed liquid, the seed liquid is inoculated into a fermentation medium, and a fermentation liquid is obtained after the cultivation is completed; S2, adding a treatment agent to the fermentation liquid obtained in step S1, stirring, heating to 100-120°C and keeping warm for 10-20 minutes to obtain a treated liquid, cooling, extracting with ethanol, drying, and crushing to obtain low pyruvate xanthan gum; In step S1, the fermentation medium components include: 28-32 g / L ginger leaf powder, 15-25 g / L starch, 10-15 g / L peptone, pH 6.8-7.2; the fermentation culture conditions are: culture at 28-35° C., 180-220 r / min constant temperature shaking table for 50-60 hours; In step S2, the treatment agent is an organic acid and / or an inorganic salt; The organic acid is citric acid and / or ferulic acid; the inorganic salt is magnesium sulfate and / or zinc sulfate; The amount of the treatment agent added in step S2 is 5-10% of the mass of the fermentation liquid.

2. The method for preparing low-pyruvic acid xanthan gum according to claim 1, wherein The activation culture medium components in step S1 include: 18-24 g / L malt extract, 8-12 g / L white sugar, 8-12 g / L peptone, 12-18 g / L agar, pH 6.4-6.8; the activation culture conditions are: culture at 27-32° C., 150-180 r / min constant temperature shaking table for 36-48 hours.

3. The preparation method of low-pyruvic acid xanthan gum according to claim 1, characterized in that, The seed culture medium components in step S1 include: 10-15 g / L white sugar, 8-12 g / L peptone, 8-12 g / L beef extract, 1-3 g / L ammonium citrate, 20-25 g / L glucose, and pH 6.5-7.0; the seed culture conditions are: culture at 27-32° C., 150-180 r / min constant temperature shaking table for 20-24 hours.

4. The method for preparing low-pyruvic acid xanthan gum according to claim 1, wherein The ginger leaf powder is prepared by the following method: fresh ginger leaves are washed and put into boiling water for blanching for 1-2 minutes, cut into small sections after blanching, dried at a temperature of 50-60° C., and crushed through a 50-70 mesh sieve to obtain the ginger leaf powder.

5. The method for preparing low-pyruvic acid xanthan gum according to claim 1, wherein The treating agent comprises citric acid and magnesium sulfate in a mass ratio of 3-5:

1.

6. The method for preparing low-pyruvic acid xanthan gum according to claim 1, characterized in that: The ethanol extraction in step S2 specifically refers to: extracting the treated liquid with an ethanol solution with a volume fraction of 95% at a volume ratio of 1:1.2-1.5, discarding the ethanol layer liquid, and taking the precipitate.

7. A low-pyruvate xanthan gum, characterized in that: The low pyruvate xanthan gum is prepared by the preparation method of any one of claims 1 to 6.

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