A kind of high whiteness fermented sodium propionate and preparation method thereof

Abstract

The invention relates to the technical field of microbial fermentation, and specifically discloses a high-whiteness fermented sodium propionate and a preparation method thereof. The preparation method of the high-whiteness fermented sodium propionate comprises: inoculating a propionibacterium seed liquid into a fermentation medium for anaerobic fermentation, stirring and mixing the liquid alkali to maintain the fermentation pH to 6.5-7.0, adding modified bentonite to heat and stir after fermentation and culture to obtain a sodium propionate fermentation liquid; filtering the sodium propionate fermentation liquid through a ceramic membrane and an ultrafiltration membrane in sequence, evaporating and concentrating the liquid, adding acid to adjust the pH, and spray drying to obtain the high-whiteness fermented sodium propionate; the obtained high-whiteness fermented sodium propionate product has high whiteness, high light transmittance, high yield, excellent comprehensive performance, meets the requirements of national food safety standards, and has broad market prospects.

Description

Technical Field

[0001] The invention relates to the technical field of microbial fermentation, and more specifically to high-whiteness fermented sodium propionate and a preparation method thereof. Background Art

[0002] As an acidic preservative, sodium propionate has a wide range of antibacterial effects on molds, yeasts and bacteria. The main reason why sodium propionate has an antiseptic effect is that it contains undissociated propionic acid, so it is most active in acidic pH. Sodium propionate is used as a food preservative, suitable for use as a preservative in pastries and as a bread mold inhibitor, and because it is almost non-toxic to the human body, it is increasingly widely used. The traditional method for producing sodium propionate is to neutralize propionic acid (C3H6O2) solution with sodium hydroxide (NaOH) or sodium carbonate (Na2CO3). Although the above neutralization method is simple and easy to produce sodium propionate, it has the disadvantages of low purity, environmental pollution, complex processing and high cost.

[0003] With the development of biotechnology, the preparation of sodium propionate by fermentation has gradually attracted attention. Fermentation of sodium propionate is to use microorganisms to produce sodium propionate through a fermentation process under specific conditions. It has the advantages of environmentally friendly and renewable fermentation raw materials, mild fermentation process, less by-products, simple purification steps, and helps to improve the purity of the final sodium propionate product. And fermentation sodium propionate is widely used. It is often used as a leavening agent, dough regulator, buffer, tissue improver, curing agent, nutritional supplement, chelating agent, etc. in the food industry; such as baked products, cake leavening agent; bread, biscuit fermentation aid, buffer, pectin curing agent (gel effect); yeast food meat product tissue improver; used in brewing can also increase saccharification power, improve fermentation capacity, etc. Although the fermentation method for preparing sodium propionate has many advantages over the traditional chemical neutralization method, the existing fermentation method generally has the defects of low yield of sodium propionate product, low whiteness, low light transmittance, etc., which seriously limits the application of fermentation sodium propionate. Based on the above statement, the present invention provides a high-whiteness fermentation sodium propionate and its preparation method. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-whiteness fermented sodium propionate and a preparation method thereof.

[0005] In a first aspect, the present invention provides a method for preparing high-whiteness fermented sodium propionate, which adopts the following technical scheme:

[0006] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0007] S1. The control components include 34-42 g / L of composite carbon source, 14-20 g / L of peptone, 2-3 g / L of sodium dihydrogen phosphate, 1.0-1.5 g / L of potassium dihydrogen phosphate, 0.25-0.45 g / L of magnesium sulfate heptahydrate, 0.02-0.04 g / L of calcium chloride dihydrate, 0.01-0.014 g / L of manganese sulfate, and 0.005-0.01 g / L of iron sulfate, and the initial pH is 6.5-7.0, to prepare a fermentation medium;

[0008] S2, inoculating the propionibacterium seed liquid into the fermentation medium for anaerobic fermentation, the fermentation temperature is 30-37°C, and liquid alkali is added at 100-140rpm to maintain the fermentation pH to 6.5-7.0. After fermentation and culturing for 48-72h, modified bentonite is added and stirred to obtain sodium propionate fermentation liquid;

[0009] S3, filtering the sodium propionate fermentation liquid through a ceramic membrane and an ultrafiltration membrane in sequence, and then evaporating and concentrating it, adding acid to adjust the pH, and then spray drying it to obtain high-whiteness fermented sodium propionate.

[0010] Preferably, the composite carbon source in step S1 comprises lactic acid, galacturonic acid and glycerol in a mass ratio of 28-30:1-3:1-3.

[0011] Preferably, the propionibacterium seed solution in step S2 is obtained by the following method:

[0012] A1. Inoculate Propionibacterium into activation culture medium and culture anaerobically at 30-37°C for 36-48h to obtain activated strains;

[0013] A2. Inoculate the activated bacteria into the seed culture medium and culture anaerobically at 30-37℃ until OD 600 To 6.8-7.5, obtain Propionibacterium seed liquid.

[0014] Preferably, the propionibacterium in step A1 is at least one of Propionibacterium acidipropionici, Propionibacterium shermanii, and Propionibacterium jannaschii.

[0015] Preferably, the inoculation amount of the activated bacteria in step A2 is 8-12%.

[0016] Preferably, the components of the seed culture medium in step A2 are as follows: glucose 15-20 g / L, peptone 8-12 g / L, beef extract 4-6 g / L, agar 8-12 g / L, potassium dihydrogen phosphate 3-5 g / L, dipotassium hydrogen phosphate 2-4 g / L, magnesium sulfate heptahydrate 0.3-1 g / L, ferrous sulfate heptahydrate 0.1-0.5 g / L, and the pH is 6.4-6.8.

[0017] Preferably, the inoculation amount of the Propionibacterium seed solution in step S2 is 10-20%.

[0018] Preferably, the propionibacterium seed solution comprises a Propionibacterium acidipropionici seed solution and a Propionibacterium janaschii seed solution in a volume ratio of 1:1.

[0019] Preferably, the modified bentonite in step S2 is prepared by the following method:

[0020] B1. Add bentonite to 0.2-0.5M hydrochloric acid solution, stir for 0.5-1h, add 1-5% of the mass of bentonite sophorolipids and continue stirring for 1-2h, wash until neutral, and obtain pretreated bentonite;

[0021] B2. Add polyvinyl pyrrolidone and sodium polyacrylate to deionized water in sequence, heat to 80-90°C, stir to dissolve to obtain a polymer solution, add pretreated bentonite to the polymer solution, keep warm and stir for 1-2 hours, wash and dry to obtain modified bentonite.

[0022] Preferably, in step B1, the mass ratio of bentonite to hydrochloric acid solution is 1:8-12.

[0023] Preferably, in step B2, the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water is 1-3:1-3:10-15; the mass ratio of polymer solution and pretreated bentonite is 10:1.8-3.

[0024] Preferably, in step S3, the pore size of the ceramic membrane is 10-50 nm, the filtration temperature of the ceramic membrane is 15-45° C., and the filtration pressure is 0.18-0.25 MPa; the pore size of the ultrafiltration membrane is 500-1000 Da, the filtration temperature of the ultrafiltration membrane is 15-40° C., and the filtration pressure is 0.45-0.8 MPa.

[0025] Preferably, the evaporation concentration temperature in step S3 is 65-85° C., and the concentration multiple is 10-15 times.

[0026] Preferably, the adding of acid to adjust the pH in step S3 specifically refers to: adding concentrated hydrochloric acid to adjust the pH value to 5-7.

[0027] Preferably, the spray drying conditions in step S3 are: inlet air temperature 180-200°C, outlet air temperature 90-120°C, atomization frequency 210-230Hz, and feed rate 0.7-1.5L / h.

[0028] In a second aspect, the present invention provides a high-whiteness fermented sodium propionate, which adopts the following technical scheme:

[0029] A high-whiteness fermented sodium propionate is prepared by the preparation method of the high-whiteness fermented sodium propionate.

[0030] In summary, the present invention has the following beneficial effects:

[0031] The invention connects propionibacterium seed liquid to fermentation medium for anaerobic fermentation, adds liquid alkali during fermentation to maintain fermentation pH, adds modified bentonite after fermentation is completed, heats and stirs to obtain sodium propionate fermentation liquid, among the propionibacteria selected by the invention, propionibacterium acidi-producing has high propionic acid production capacity, strong adaptability, and can significantly improve the yield of sodium propionate; Propionibacterium schie has fast fermentation speed and good nutritional characteristics, and can produce nutrients for improving the culture medium; Propionibacterium jannaschii has high metabolic activity and high tolerance, and can quickly convert carbon sources into propionic acid, thereby improving fermentation efficiency and product yield; the invention finds that the quality of the product obtained by fermentation with the combined strain is further improved compared with that of the single strain, because the combined strain can coordinate with each other during the fermentation process, optimize metabolic balance, realize diversification and complementarity of metabolic pathways, improve overall fermentation efficiency and yield, avoid byproducts in the metabolic process of the single strain, reduce the generation of impurities, and thus effectively reduce the influence of adverse factors on product purity, yield, whiteness and transmittance.

[0032] The present invention adopts lactic acid, galacturonic acid and glycerol as a composite carbon source, which can provide diversified nutrients and meet the growth and metabolic requirements of propionibacterium. Among them, lactic acid, as the main carbon source for the growth of propionibacterium, can directly participate in the metabolic pathway and increase the yield of propionic acid. Galacturonic acid, a polysaccharide degradation product, can be degraded and converted into simple sugars by propionibacterium and further utilized to improve the overall carbon source utilization rate. Glycerol can produce more energy and intermediate metabolites through the tricarboxylic acid cycle and further promote the synthesis of propionic acid. By controlling the dosage of lactic acid, galacturonic acid and glycerol, the growth of bacteria and the generation of metabolites can be effectively balanced, metabolic byproducts caused by a single carbon source can be avoided, the generation of impurities can be reduced, and the purity, yield, whiteness and transmittance of the product can be further improved.

[0033] The invention adds hydrochloric acid solution to disperse bentonite, adds sophora biosurfactant to obtain pretreated bentonite, and then adds polymer solution obtained by adding polyvinyl pyrrolidone, sodium polyacrylate and deionized water to obtain modified bentonite; the acid treatment can activate the bentonite, improve its specific surface area and pore structure, and enhance its adsorption capacity for organic matter and metal ions; the introduction of sophora biosurfactant can increase the hydrophilicity and dispersibility of the bentonite, improve its stability in the aqueous solution, and also improve the adsorption selectivity of the bentonite; the addition of the polymer solution can further improve the dispersibility of the bentonite in the aqueous solution, prevent particle agglomeration, and improve the adsorption effect. When the modified bentonite is added, the adsorption sites of the bentonite can be increased, and its adsorption capacity for small molecular impurities and ions can be improved; after the fermentation is completed, the modified bentonite is added and the temperature is raised and stirred to effectively remove fine suspended matter and microbial residues, improve the subsequent filtration efficiency, reduce losses, and increase the product yield; the modified bentonite has a large specific surface area and good adsorption performance, and can effectively adsorb pigments, metal ions and other organic impurities in the fermentation liquid, thereby significantly improving the whiteness of the product; the impurities in the fermentation liquid treated with modified bentonite are reduced, the filtration effect of the ceramic membrane and the ultrafiltration membrane is better, and the whiteness and light transmittance of the final product are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a product picture of high-whiteness fermented sodium propionate powder prepared in Example 1 of the present invention and Comparative Example 4. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the embodiments.

[0036] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0037] Unless otherwise specified, the materials, reagents, etc. used in the examples and comparative examples of the present invention can be obtained from commercial sources. Among them, Propionibacterium acidipropionici is Propionibacterium acidipropionici ATCC25562, Propionibacterium schermeri is Propionibacterium schermeri CICC10019, and Propionibacterium jannaschii is Propionibacterium jannaschii ATCC 4964, all of which were purchased from Shanghai Collection Biotechnology Center.

[0038] The activation medium was Aiculture® PYG liquid medium GF1083, purchased from Shenzhen Comma Biotechnology Co., Ltd.

[0039] The components of the seed culture medium are as follows: glucose 18 g / L, peptone 10 g / L, beef extract 5 g / L, agar 10 g / L, potassium dihydrogen phosphate 4 g / L, dipotassium hydrogen phosphate 3 g / L, magnesium sulfate heptahydrate 0.5 g / L, ferrous sulfate heptahydrate 0.3 g / L, pH 6.6.

[0040] The bentonite is calcium-based bentonite, brand Bochuan, model BC-PRT, active ingredient content 99%, particle size 325 mesh, purchased from Lingshou County Bochuan Mineral Products Processing Plant.

[0041] Sophorolipids, brand name Yamade, with an active ingredient content of 98%, were purchased from Hubei Yamade Biopharmaceutical Co., Ltd.

[0042] The polyvinyl pyrrolidone was povidone K30, brand Qiansheng Chemical, with an active ingredient content of 99%, purchased from Shandong Qiansheng Chemical Co., Ltd.

[0043] Sodium polyacrylate, brand Zhuogu, content 99%, purchased from Henan Zhuogu Biotechnology Co., Ltd.

[0044] Preparation Examples 1-3 and Comparative Preparation Examples 1-2 provide a method for preparing a modified bentonite.

[0045] Preparation Example 1

[0046] Modified bentonite is prepared by the following method:

[0047] B1. Control the mass ratio of bentonite and hydrochloric acid solution to 1:8, add bentonite to 0.2M hydrochloric acid solution, stir at a speed of 400r / min for 1h, add 1% of the mass of bentonite sophorolipid and continue stirring for 2h, deionize and wash to neutrality to obtain pretreated bentonite;

[0048] B2. Control the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water to be 1:3:10, add polyvinyl pyrrolidone and sodium polyacrylate into deionized water in turn, heat to 80°C, stir at 300 r / min until dissolved to obtain a polymer solution, control the mass ratio of the polymer solution to pretreated bentonite to be 10:1.8, add pretreated bentonite to the polymer solution, keep warm and stir for 2 hours, deionize and wash, and then dry at 80°C to constant weight to obtain modified bentonite.

[0049] Preparation Example 2

[0050] Modified bentonite is prepared by the following method:

[0051] B1. Control the mass ratio of bentonite and hydrochloric acid solution to 1:10, add bentonite to 0.3M hydrochloric acid solution, stir at a speed of 500r / min for 0.8h, add 3% of the mass of bentonite sophora biosurfactant and continue stirring for 1.5h, deionize and wash to neutrality to obtain pretreated bentonite;

[0052] B2. Control the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water to be 2:2:13, add polyvinyl pyrrolidone and sodium polyacrylate into deionized water in turn, heat to 85°C, stir at 400 r / min until dissolved to obtain a polymer solution, control the mass ratio of the polymer solution to pretreated bentonite to be 10:2.4, add pretreated bentonite to the polymer solution, keep warm and stir for 1.5 hours, wash with deionizer, and dry at 90°C to constant weight to obtain modified bentonite.

[0053] Preparation Example 3

[0054] Modified bentonite is prepared by the following method:

[0055] B1. Control the mass ratio of bentonite and hydrochloric acid solution to 1:12, add bentonite to 0.5M hydrochloric acid solution, stir at a speed of 600r / min for 0.5h, add 5% of the mass of bentonite sophora biosurfactant and continue stirring for 1h, deionize and wash to neutrality to obtain pretreated bentonite;

[0056] B2. Control the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water to be 3:1:15, add polyvinyl pyrrolidone and sodium polyacrylate into deionized water in turn, heat to 90°C, stir at 500 r / min until dissolved to obtain a polymer solution, control the mass ratio of the polymer solution to pretreated bentonite to be 10:3, add pretreated bentonite to the polymer solution, keep warm and stir for 1 hour, deionize and wash, and dry at 100°C to constant weight to obtain modified bentonite.

[0057] Comparative Preparation Example 1

[0058] Modified bentonite is prepared by the following method:

[0059] B1. The mass ratio of bentonite to hydrochloric acid solution was controlled to be 1:8, the bentonite was added to a 0.2M hydrochloric acid solution, stirred at a speed of 400 r / min for 3 h, and deionized and washed until neutral to obtain pretreated bentonite;

[0060] B2. Control the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water to be 1:3:10, add polyvinyl pyrrolidone and sodium polyacrylate into deionized water in turn, heat to 80°C, stir at 300 r / min until dissolved to obtain a polymer solution, control the mass ratio of the polymer solution to pretreated bentonite to be 10:1.8, add pretreated bentonite to the polymer solution, keep warm and stir for 2 hours, deionize and wash, and then dry at 80°C to constant weight to obtain modified bentonite.

[0061] Comparative Preparation Example 2

[0062] Modified bentonite is prepared by the following method:

[0063] B1. Control the mass ratio of bentonite and hydrochloric acid solution to 1:8, add bentonite to 0.2M hydrochloric acid solution, stir at a speed of 400r / min for 1h, add 1% of the mass of bentonite sophorolipid and continue stirring for 2h, deionize and wash to neutrality to obtain pretreated bentonite;

[0064] B2. Control the mass ratio of sodium polyacrylate and deionized water to be 4:10, add sodium polyacrylate to deionized water, heat to 80°C, and stir at 300 r / min until dissolved to obtain a polymer solution, control the mass ratio of the polymer solution to pretreated bentonite to be 10:1.8, add pretreated bentonite to the polymer solution, keep warm and stir for 2 hours, deionize and wash, and then dry at 80°C to constant weight to obtain modified bentonite.

[0065] Embodiment 1-7 provides a high-whiteness fermented sodium propionate and a preparation method thereof.

[0066] Example 1

[0067] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0068] S1. Prepare fermentation medium:

[0069] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0070] S2, preparing sodium propionate fermentation broth:

[0071] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0072] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0073] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0074] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0075] Example 2

[0076] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0077] S1. Prepare fermentation medium:

[0078] The control components include 38 g / L of composite carbon source, 17 g / L of peptone, 2.5 g / L of sodium dihydrogen phosphate, 1.2 g / L of potassium dihydrogen phosphate, 0.35 g / L of magnesium sulfate heptahydrate, 0.03 g / L of calcium chloride dihydrate, 0.012 g / L of manganese sulfate, and 0.008 g / L of iron sulfate. The initial pH is 6.8 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 29:2:2.

[0079] S2, preparing sodium propionate fermentation broth:

[0080] The Propionibacterium sieversii was inoculated into the activation culture medium and anaerobically cultured at 34°C for 42 hours to obtain the activated strain of Propionibacterium sieversii.

[0081] The activated strain inoculation amount was controlled to 10%, and the activated strain of Propionibacterium schizophylla was inoculated into the seed culture medium and cultured anaerobically at 34°C until the OD 600 to 7.2, to obtain the seed solution of Propionibacterium sieversii;

[0082] The total inoculation amount of the seed liquid was controlled to be 15%, and the Propionibacterium sieve seed liquid was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 34° C., and liquid alkali was added at a stirring and mixing flow of 120 rpm to maintain the fermentation pH to 6.8. After fermentation and cultivation for 60 hours, 15% of the mass of the fermentation medium of the modified bentonite in Preparation Example 2 was added and the temperature was raised to 100° C. After stirring at a speed of 400 r / min for 2.5 hours, the mixture was centrifuged at a speed of 9000 r / min for 12 minutes to obtain a sodium propionate fermentation liquid.

[0083] S3. Control the filtration temperature of the ceramic membrane to be 25°C and the filtration pressure to be 0.22MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 30nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 25°C and the filtration pressure to be 0.5MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 800Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 12 times at a temperature of 75°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.18, and obtain an acid-adjusting solution, control the inlet temperature to be 190°C, the outlet temperature to be 105°C, the atomization frequency to be 220Hz, the feed rate to be 1.1L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0084] Example 3

[0085] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0086] S1. Prepare fermentation medium:

[0087] The control components include 34 g / L of composite carbon source, 14 g / L of peptone, 2 g / L of sodium dihydrogen phosphate, 1.0 g / L of potassium dihydrogen phosphate, 0.25 g / L of magnesium sulfate heptahydrate, 0.02 g / L of calcium chloride dihydrate, 0.01 g / L of manganese sulfate, and 0.005 g / L of iron sulfate. The initial pH is 6.7 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 28:3:1.

[0088] S2, preparing sodium propionate fermentation broth:

[0089] The Propionibacterium janaschii was inoculated into the activation culture medium and anaerobically cultured at 30°C for 48 hours to obtain the activated strain of Propionibacterium janaschii.

[0090] The activated strain inoculation amount was controlled to 8%, and the activated strain of Propionibacterium janaphyllii was inoculated into the seed culture medium and cultured anaerobically at 30°C until the OD 600 to 6.8, to obtain the Propionibacterium janaschii seed solution;

[0091] The total inoculation amount of the seed liquid was controlled to be 10%, and the Propionibacterium janaxia seed liquid was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 30° C., and liquid alkali was added at 100 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 72 hours, 12% of the mass of the fermentation medium of the modified bentonite in Preparation Example 3 was added and the temperature was raised to 90° C. After stirring at a speed of 300 r / min for 3 hours, the mixture was centrifuged at a speed of 8000 r / min for 15 minutes to obtain a sodium propionate fermentation liquid.

[0092] S3. Control the filtration temperature of the ceramic membrane to be 15°C and the filtration pressure to be 0.18 MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 50 nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 15°C and the filtration pressure to be 0.45 MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 1000 Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 10 times at a temperature of 65°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.21, and obtain an acid-adjusting solution, control the inlet temperature to be 180°C, the outlet temperature to be 90°C, the atomization frequency to be 210 Hz, the feed rate to be 0.7 L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0093] Example 4

[0094] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0095] S1. Prepare fermentation medium:

[0096] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0097] S2, preparing sodium propionate fermentation broth:

[0098] Propionibacterium acidipropionici, Propionibacterium schernoris and Propionibacterium jannaschii were inoculated into activation culture medium respectively, and cultured anaerobically at 37°C for 36 hours to obtain activated strains of Propionibacterium acidipropionici, Propionibacterium schernoris and Propionibacterium jannaschii;

[0099] The activated strain inoculation amount was controlled to be 12%, and the activated strains of Propionibacterium acidipropionici, Propionibacterium schizophyllum, and Propionibacterium jannaschii were inoculated into the seed culture medium respectively, and cultured anaerobically at 37°C until the OD 600to 7.5, to obtain the seed solution of Propionibacterium acidipropionici, the seed solution of Propionibacterium schrei and the seed solution of Propionibacterium janaschii;

[0100] The total inoculation amount of the seed solution was controlled to be 20%, and the seed solution of Propionibacterium acidipropionici, the seed solution of Propionibacterium schizophyllum and the seed solution of Propionibacterium jannaschii in a volume ratio of 1:1:1 were co-inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added, the temperature was raised to 110° C., and the mixture was stirred at a speed of 500 r / min for 2 hours, and then centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid;

[0101] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0102] Example 5

[0103] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0104] S1. Prepare fermentation medium:

[0105] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0106] S2, preparing sodium propionate fermentation broth:

[0107] Propionibacterium acidipropionici and Propionibacterium sievei are inoculated into activation culture medium respectively, and cultured anaerobically at 37°C for 36 hours to obtain activated strains of Propionibacterium acidipropionici and Propionibacterium sievei;

[0108] The activated strain inoculation amount was controlled to be 12%, and the activated strains of Propionibacterium acidipropionici and Propionibacterium schizophylla were inoculated into the seed culture medium respectively, and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici and Propionibacterium sheacheni;

[0109] The total inoculation amount of the seed solution was controlled to be 20%, and the seed solution of Propionibacterium acidipropionici and Propionibacterium sieveii in a volume ratio of 1:1 were co-inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0110] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0111] Example 6

[0112] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0113] S1. Prepare fermentation medium:

[0114] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0115] S2, preparing sodium propionate fermentation broth:

[0116] Propionibacterium acidipropionici and Propionibacterium jannaschii were inoculated into activation culture medium respectively, and cultured anaerobically at 37°C for 36 hours to obtain activated strains of Propionibacterium acidipropionici and Propionibacterium jannaschii;

[0117] The activated strain inoculation amount was controlled to be 12%, and the activated strains of Propionibacterium acidipropionici and Propionibacterium jannaschii were inoculated into the seed culture medium respectively, and cultured anaerobically at 37°C until OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici and the seed solution of Propionibacterium janaschii;

[0118] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici and the seed liquid of Propionibacterium jannaschii in a volume ratio of 1:1 were co-inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at a stirring and mixing flow of 140 rpm to maintain the fermentation pH to 6.5. After fermentation and cultivation for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C., and the mixture was stirred at a speed of 500 r / min for 2 hours, and then centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid;

[0119] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0120] Example 7

[0121] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0122] S1. Prepare fermentation medium:

[0123] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0124] S2, preparing sodium propionate fermentation broth:

[0125] Propionibacterium schizophyllum and Propionibacterium jannaschii were inoculated into activation culture medium respectively, and cultured anaerobically at 37°C for 36 hours to obtain activated strains of Propionibacterium schizophyllum and Propionibacterium jannaschii;

[0126] The activated bacterial strain inoculation amount was controlled to 12%, and the activated strains of Propionibacterium schizophyllum and Propionibacterium jannaschii were inoculated into the seed culture medium respectively, and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain Propionibacterium schizophyllum seed solution and Propionibacterium janaschii seed solution;

[0127] The total inoculation amount of the seed solution was controlled to be 20%, and the seed solution of Propionibacterium schizophyllum and the seed solution of Propionibacterium janaschii in a volume ratio of 1:1 were co-inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at a stirring and mixing flow of 140 rpm to maintain the fermentation pH to 6.5. After fermentation and cultivation for 48 hours, 18% of the modified bentonite in Preparation Example 1 by mass of the fermentation medium was added, the temperature was raised to 110° C., and the mixture was stirred at a speed of 500 r / min for 2 hours, and then centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid;

[0128] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0129] In order to verify the comprehensive performance of the high-whiteness fermented sodium propionate prepared in Examples 1-7 of the present invention, the applicant set up comparative examples 1-6, which are as follows:

[0130] Comparative Example 1

[0131] The difference between Comparative Example 1 and Example 1 is that the composite carbon source is replaced by a single carbon source, lactic acid, as follows:

[0132] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0133] S1. Prepare fermentation medium:

[0134] The control components include 42 g / L lactic acid, 20 g / L peptone, 3 g / L sodium dihydrogen phosphate, 1.5 g / L potassium dihydrogen phosphate, 0.45 g / L magnesium sulfate heptahydrate, 0.04 g / L calcium chloride dihydrate, 0.014 g / L manganese sulfate, and 0.01 g / L iron sulfate. The initial pH is 6.6 and sterilized at 121°C for 30 min to prepare a fermentation medium.

[0135] S2, preparing sodium propionate fermentation broth:

[0136] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0137] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0138] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0139] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0140] Comparative Example 2

[0141] The difference between Comparative Example 2 and Example 1 is that the composite carbon source includes lactic acid and galacturonic acid in a mass ratio of 30:1, as follows:

[0142] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0143] S1. Prepare fermentation medium:

[0144] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid and galacturonic acid in a mass ratio of 30:1.

[0145] S2, preparing sodium propionate fermentation broth:

[0146] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0147] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0148] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0149] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0150] Comparative Example 3

[0151] The difference between Comparative Example 3 and Example 1 is that the composite carbon source includes lactic acid and glycerol in a mass ratio of 30:3, as follows:

[0152] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0153] S1. Prepare fermentation medium:

[0154] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the culture medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid and glycerol in a mass ratio of 30:3.

[0155] S2, preparing sodium propionate fermentation broth:

[0156] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0157] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0158] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0159] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0160] Comparative Example 4

[0161] The difference between Comparative Example 4 and Example 1 is that the modified bentonite in Preparation Example 1 in step S2 is replaced by the modified bentonite in Comparative Preparation Example 1, as follows:

[0162] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0163] S1. Prepare fermentation medium:

[0164] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0165] S2, preparing sodium propionate fermentation broth:

[0166] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0167] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0168] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culture for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Comparative Preparation Example 1 was added and the temperature was raised to 110° C., and the mixture was stirred at a speed of 500 r / min for 2 hours, and then centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid;

[0169] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0170] Comparative Example 5

[0171] The difference between Comparative Example 5 and Example 1 is that the modified bentonite in Preparation Example 1 in step S2 is replaced by the modified bentonite in Comparative Preparation Example 2, as follows:

[0172] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0173] S1. Prepare fermentation medium:

[0174] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0175] S2, preparing sodium propionate fermentation broth:

[0176] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0177] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0178] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culture for 48 hours, 18% of the mass of the fermentation medium was added. The modified bentonite in Comparative Preparation Example 2 was heated to 110° C., stirred at a speed of 500 r / min for 2 hours, and then centrifuged at a speed of 10000 r / min for 10 minutes to obtain sodium propionate fermentation liquid;

[0179] S3. Control the filtration temperature of the ceramic membrane to be 35°C and the filtration pressure to be 0.25MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10nm to obtain a ceramic membrane clear liquid; control the filtration temperature of the ultrafiltration membrane to be 35°C and the filtration pressure to be 0.55MPa, and pass the ceramic membrane clear liquid through an ultrafiltration membrane with a pore size of 500Da to obtain an ultrafiltration membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ultrafiltration membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230Hz, the feed rate to 1.5L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0180] Comparative Example 6

[0181] The difference between Comparative Example 6 and Example 1 is that the ultrafiltration membrane filtration operation is reduced in step S3, which is as follows:

[0182] A method for preparing high-whiteness fermented sodium propionate comprises the following steps:

[0183] S1. Prepare fermentation medium:

[0184] The control components include 42 g / L of composite carbon source, 20 g / L of peptone, 3 g / L of sodium dihydrogen phosphate, 1.5 g / L of potassium dihydrogen phosphate, 0.45 g / L of magnesium sulfate heptahydrate, 0.04 g / L of calcium chloride dihydrate, 0.014 g / L of manganese sulfate, and 0.01 g / L of iron sulfate. The initial pH is 6.6 and the medium is sterilized at 121° C. for 30 min to prepare a fermentation medium, wherein the composite carbon source includes lactic acid, galacturonic acid, and glycerol in a mass ratio of 30:1:3.

[0185] S2, preparing sodium propionate fermentation broth:

[0186] The Propionibacterium acidipropionici was inoculated into an activation culture medium and anaerobically cultured at 37°C for 36 hours to obtain an activated strain of Propionibacterium acidipropionici.

[0187] The activated strain inoculation amount was controlled to 12%, and the activated strain of Propionibacterium acidipropionici was inoculated into the seed culture medium and cultured anaerobically at 37°C until the OD 600 to 7.5, to obtain the seed solution of Propionibacterium acidipropionici;

[0188] The total inoculation amount of the seed liquid was controlled to be 20%, and the seed liquid of Propionibacterium acidipropionici was inoculated into the fermentation medium for anaerobic fermentation. The fermentation temperature was 37° C., and the liquid alkali was added at 140 rpm to maintain the fermentation pH to 6.5. After fermentation and culturing for 48 hours, 18% of the mass of the fermentation medium of the modified bentonite in Preparation Example 1 was added and the temperature was raised to 110° C. After stirring at a speed of 500 r / min for 2 hours, the mixture was centrifuged at a speed of 10000 r / min for 10 minutes to obtain a sodium propionate fermentation liquid.

[0189] S3. Control the filtration temperature of the ceramic membrane to 35°C and the filtration pressure to 0.25 MPa, and pass the sodium propionate fermentation liquid through a ceramic membrane with a pore size of 10 nm to obtain a ceramic membrane clear liquid; use a rotary evaporator to evaporate and concentrate the ceramic membrane clear liquid 15 times at a temperature of 85°C to obtain a concentrated solution, add concentrated hydrochloric acid to adjust the pH value of the concentrated solution to 6.22 to obtain an acid-adjusting solution, control the inlet temperature to 200°C, the outlet temperature to 120°C, the atomization frequency to 230 Hz, the feed rate to 1.5 L / h, and spray-dry the acid-adjusting solution to obtain high-whiteness fermented sodium propionate.

[0190] Performance Testing

[0191] The comprehensive performance of the high-whiteness fermented sodium propionate prepared in Examples 1-7 of the present invention and Comparative Examples 1-6 was tested respectively, and the specific method is as follows:

[0192] Whiteness: The whiteness of the fermented propionic acid product is measured using a whiteness tester;

[0193] Light transmittance: Use a light transmittance meter to measure the light transmittance of the fermented propionic acid product;

[0194] Yield: Calculate the yield of sodium propionate product according to the yield calculation method. The specific calculation formula is as follows:

[0195] Sodium propionate yield = {(C1×V1)÷(C0×V0)}×100%, where C0 is the sodium propionate concentration in the initial sodium propionate fermentation broth (g / L), V0 is the volume of the initial sodium propionate fermentation broth (L); C1 is the sodium propionate concentration in the acid-adjusting broth after treatment (g / L), and V1 is the volume of the acid-adjusting broth after treatment (L);

[0196] The results are shown in Table 1 below.

[0197] Table 1:

[0198]

[0199] In addition, referring to the inspection method of the national standard GB 25549-2010 "National Food Safety Standard Food Additive Sodium Propionate", the fermented sodium propionate prepared in Examples 1-7 of the present invention was tested, and the test results all met the standard technical indicator requirements. Table 2 below lists the test results of the fermented sodium propionate prepared in Example 1 of the present invention.

[0200] Table 2:

[0201]

[0202] Combining the above Table 1, Table 2 and Figure 1 The results show that the comprehensive performance of the high-whiteness fermented sodium propionate prepared in Examples 1-7 of the present invention is significantly better than that of Comparative Examples 1-6. The sodium propionate product obtained by the present invention has high whiteness, high light transmittance, high yield, excellent comprehensive performance, meets the requirements of national food safety standards, and has broad market prospects. Figure 1 This is a product picture of high-whiteness fermented sodium propionate powder prepared in Example 1 and Comparative Example 4 of the present invention, with Comparative Example 4 on the left and Example 1 on the right.

[0203] It can be seen from Examples 1 and 4-7 that the quality of the product obtained by fermentation with a combination of strains is further improved compared with that of a single strain. Among them, Example 6 uses a combination of Propionibacterium acidipropionici and Propionibacterium janaschii for fermentation, and the sodium propionate product obtained has the best comprehensive performance.

[0204] It can be seen from Example 1 and Comparative Examples 1-3 that the present invention uses lactic acid, galacturonic acid and glycerol as a composite carbon source, which can effectively balance the growth of bacteria and the generation of metabolites, avoid metabolic by-products caused by a single carbon source, reduce the generation of impurities, and further improve the product purity, yield, whiteness and transmittance.

[0205] It can be seen from Example 1 and Comparative Examples 4-5 that the selection of the modified bentonite of the present invention can effectively adsorb pigments, metal ions and other organic impurities in the fermentation broth, thereby significantly improving the whiteness of the product.

[0206] It can be seen from Example 1 and Comparative Example 6 that the present invention uses a ceramic membrane and an ultrafiltration membrane for double filtration, which can further improve the comprehensive performance of the sodium propionate product.

[0207] 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 high whiteness fermented sodium propionate, characterized in that: The following steps are involved: S1. The control components include 34-42 g / L of composite carbon source, 14-20 g / L of peptone, 2-3 g / L of sodium dihydrogen phosphate, 1.0-1.5 g / L of potassium dihydrogen phosphate, 0.25-0.45 g / L of magnesium sulfate heptahydrate, 0.02-0.04 g / L of calcium chloride dihydrate, 0.01-0.014 g / L of manganese sulfate, and 0.005-0.01 g / L of iron sulfate, and the initial pH is 6.5-7.0, to prepare a fermentation medium; S2, inoculating the propionibacterium seed liquid into the fermentation medium for anaerobic fermentation, the fermentation temperature is 30-37°C, and liquid alkali is added at 100-140rpm to maintain the fermentation pH to 6.5-7.

0. After fermentation and culturing for 48-72h, modified bentonite is added and stirred to obtain sodium propionate fermentation liquid; S3, filtering the sodium propionate fermentation broth through a ceramic membrane and an ultrafiltration membrane in sequence, evaporating and concentrating the broth, adding acid to adjust the pH, and spray drying to obtain high-whiteness fermented sodium propionate; In step S1, the composite carbon source comprises lactic acid, galacturonic acid and glycerol in a mass ratio of 28-30:1-3:1-3; The propionibacterium seed liquid is a Propionibacterium acidipropionici seed liquid and a Propionibacterium janaschii seed liquid in a volume ratio of 1:1; The modified bentonite in step S2 is prepared by the following method: B1. Add bentonite to 0.2-0.5M hydrochloric acid solution, stir for 0.5-1h, add 1-5% of the mass of bentonite sophorolipids and continue stirring for 1-2h, wash until neutral, and obtain pretreated bentonite; B2. Add polyvinyl pyrrolidone and sodium polyacrylate to deionized water in sequence, heat to 80-90°C, stir to dissolve to obtain a polymer solution, add pretreated bentonite to the polymer solution, keep warm and stir for 1-2 hours, wash and dry to obtain modified bentonite.

2. The method for preparing high whiteness fermented sodium propionate according to claim 1, characterized in that: The propionibacterium seed liquid in step S2 is obtained by the following method: A1. Inoculate Propionibacterium into activation culture medium and culture anaerobically at 30-37°C for 36-48h to obtain activated strains; A2. Inoculate the activated bacteria into the seed culture medium and culture anaerobically at 30-37°C until the OD600 reaches 6.8-7.5 to obtain the propionibacterium seed solution.

3. The method for preparing high whiteness fermented sodium propionate according to claim 1, characterized in that: The inoculation amount of the propionibacterium seed solution in step S2 is 10-20%.

4. The method for preparing high whiteness fermented sodium propionate according to claim 1, characterized in that: The mass ratio of bentonite to hydrochloric acid solution in step B1 is 1:8-12; the mass ratio of polyvinyl pyrrolidone, sodium polyacrylate and deionized water in step B2 is 1-3:1-3:10-15; the mass ratio of polymer solution to pretreated bentonite is 10:1.8-3.

5. The method for preparing high whiteness fermented sodium propionate according to claim 1, characterized in that: In step S3, the pore size of the ceramic membrane is 10-50 nm, the filtration temperature of the ceramic membrane is 15-45° C., and the filtration pressure is 0.18-0.25 MPa; the pore size of the ultrafiltration membrane is 500-1000 Da, the filtration temperature of the ultrafiltration membrane is 15-40° C., and the filtration pressure is 0.45-0.8 MPa.

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