Phytobacterium plantarum with sodium nitrite degradation capability and application thereof

Abstract

The invention provides a plant lactobacillus (Lactobacillus plantarum) LHZ4 capable of efficiently degrading sodium nitrite and application of the plant lactobacillus (Lactobacillus plantarum) LHZ4, and belongs to the technical field of food biology. The strain is preserved in the China General Microbiological Culture Collection Center (CGMCC), has the number of CGMCC NO: 34622, is separated from a farmhouse self-made fermented vegetable, and has good safety and probiotic characteristics. The survival rate exceeds 68% under the conditions that the pH is 2.5-4.0 and lysozyme or phenol is contained, the oxidation resistance is remarkable, and the scavenging rates of DPPH free radicals and hydroxyl free radicals are both larger than 28%; the self-aggregation rate in 4-24 hours is 18-67%, and the hydrogel shows certain adhesion ability to Caco-2 cells. The degradation rate of the bacterium on 2.5-12.5 mmol / L of sodium nitrite in 36 hours is not lower than 95.46%. In application of white radish fermentation, the content of sodium nitrite in an experimental group inoculated with LHZ4 is reduced to 0.02 mg / L after fermentation for 120 h, which is significantly lower than that of a blank control group (0.46 mg / L), the viable count reaches 6.54 lg CFU / mL, and the fermented product has good flavor. The strain can effectively promote the fermentation process and improve the food safety.

Description

Technical Field

[0001] This invention belongs to the field of food biotechnology, specifically relating to a strain of *Lactobacillus plantarum* capable of degrading sodium nitrite and possessing good probiotic properties. Lactibacillus plantarum (and its application as a starter in the production of fermented white radish kimchi). Background Art

[0002] Fermented white radish is a uniquely flavored pickled food, but its sodium nitrite content may exceed safe limits. Sodium nitrite is a potential carcinogen; excessive intake can cause acute poisoning and even death, and also increases the risk of cancers such as stomach, breast, and prostate cancer. Although the sodium nitrite content gradually decreases after long-term fermentation, the increased production cycle raises costs. Therefore, there is a need to develop a white radish fermentation agent that can not only quickly ferment and obtain a specific flavored pickled white radish product, but also effectively reduce the sodium nitrite content in the product.

[0003] Lactic acid bacteria are commonly used as starter cultures for pickled foods. Studies have found that some lactic acid bacteria can degrade sodium nitrite through two pathways: producing sodium nitrite reductase and producing organic acids. Research has shown that the degradation ability varies among strains from different sources. Therefore, this invention focuses on the sodium nitrite degradation ability of lactic acid bacteria. A strain of lactic acid bacteria with high sodium nitrite degradation ability was isolated and purified from homemade fermented pickles and used as a starter culture for fermenting white radishes. The aim is to improve the quality of fermented white radishes, accelerate the fermentation process while reducing the sodium nitrite content, and ensure the flavor and safety of the fermented white radish product. Summary of the Invention

[0004] The problem this invention aims to solve is by providing a strain of *Lactobacillus plantarum* LHZ4 with good probiotic properties that degrades sodium nitrite. Lactibacillus plantarum This plant lactobacillus has a good ability to degrade sodium nitrite of different concentrations. It can be used as a starter culture for fermenting white radishes to accelerate the fermentation process and improve the quality of the fermented white radishes.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions.

[0006] This invention discloses a strain of *Lactobacillus plantarum* (… Lactibacillus plantarum LHZ4 is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO:34622.

[0007] The present invention also discloses a sodium nitrite degradation agent comprising the aforementioned *Lactobacillus plantarum* LHZ4.

[0008] This invention also discloses the application of the above-mentioned sodium nitrite degradation agent in degrading sodium nitrite in fermented white radish.

[0009] The present invention also discloses a fermentation agent comprising the aforementioned *Lactobacillus plantarum* LHZ4.

[0010] The present invention also discloses the application of the above-described fermenting agent in the preparation of fermented white radish products.

[0011] This invention also discloses the application of the above-mentioned fermentation agent in the preparation of fruit and vegetable enzymes and other products with low nitrite content.

[0012] This invention also discloses a method for preparing fermented white radish, characterized in that: the above-mentioned fermenting agent is used at a concentration of 1×10 6 The inoculum was introduced into the white radish fermentation system at a concentration of CFU / mL and fermented anaerobically at 37℃ for 120 hours.

[0013] Furthermore, the fermentation agent is washed with PBS buffer (pH 7.0 ± 0.2) before inoculation to remove residual culture medium.

[0014] The present invention also discloses a fermented white radish product, which is prepared by the method described above.

[0015] Furthermore, the viable bacterial count reached 6.54 lg CFU / mL ± 0.09 lg CFU / mL, and the pH value was 3.31 ± 0.01.

[0016] This invention also discloses a probiotic preparation containing the aforementioned *Lactobacillus plantarum* LHZ4, with a live bacteria count ≥ 1 × 10⁻⁶. 9 CFU / mL; the formulation has gastric acid tolerance (pH 2.5 survival rate > 68%) and antioxidant properties (hydroxyl radical scavenging rate > 96%).

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0018] This invention is the first to isolate and screen *Lactobacillus plantarum* from homemade fermented vegetables. L. plantarum, It was deposited on May 21, 2025 at the China General Microbiological Culture Collection Center, with accession number CGMCC NO: 34622, located at No. 3, Courtyard 1, Beizhan West Road, Chaoyang District, Beijing.

[0019] Further research on strain LHZ4 demonstrated that it can degrade sodium nitrite, reducing the carcinogenic risk of fermented white radish from the source. Simultaneously, the study found that this strain can accelerate the fermentation process, making it suitable as a probiotic starter. Maintaining flavor and whiteness while extending product shelf life shows great potential for rapid fermentation of white radish. Attached Figure Description

[0020] Figure 1 The graph shows the degradation rate of sodium nitrite by different strains of this invention. The letters on the horizontal axis represent different isolated strains. Lowercase letters indicate significant differences.

[0021] Figure 2 This is a colony morphology diagram of strain LHZ4 of the present invention.

[0022] Figure 3 This is an optical microscope image of the strain LHZ4 of the present invention.

[0023] Figure 4 This is a phylogenetic tree diagram of the strain LHZ4 of this invention.

[0024] Figure 5 This is a graph showing the hemolytic ability of strain LHZ4 of the present invention.

[0025] Figure 6 This is a graph showing the gelatinase production capacity of strain LHZ4 of the present invention.

[0026] Figure 7 This is a graph showing the DNase production capacity of strain LHZ4 of the present invention.

[0027] Figure 8 This is a graph showing the tolerance rate of the strain LHZ4 of this invention to extreme environments.

[0028] Figure 9 The strain LHZ4 of this invention is effective against DPPH free radicals and ABTS. + Scavenging rates of free radicals, hydroxyl radicals, and superoxide anion radicals.

[0029] Figure 10 This is a diagram showing the self-aggregation ability of strain LHZ4 of the present invention.

[0030] Figure 11 This is a diagram showing the adhesion effect of strain LHZ4 of the present invention on Caco-2.

[0031] Figure 12 The graph shows the degradation capacity of strain LHZ4 of this invention for sodium nitrite at different concentrations.

[0032] Figure 13 This is a picture of the finished product of fermented white radish after 120 hours according to the present invention.

[0033] Figure 14 The following are graphs showing the determination of the physicochemical properties of fermented white radish according to this invention. (a) Sodium nitrite content; (b) pH; (c) Viable cell count; (d) Radar graph of electronic nose analysis. Uppercase letters represent differences between groups, and lowercase letters represent differences within groups. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0035] Unless otherwise specified, all reagents and materials used in this invention are commercially available.

[0036] Example 1 L. plantarum Acquisition and identification of strain LHZ4.

[0037] 1. Isolation and screening of strain LHZ4.

[0038] Strains were screened from samples of homemade fermented vegetables. 10g of sample was mixed with 90g of sterile water, agitated thoroughly, and allowed to stand for 5-10 minutes. Then, 100µL of the mixture was transferred to MRS solid medium containing 1% CaCO3 and spread. After spreading, the medium was incubated at 37℃ for 24-48 hours. Strains exhibiting different morphologies of calcium-soluble zones on the medium were then isolated and purified. Single colonies were picked and inoculated into MRS broth and incubated for 24-48 hours. Finally, the bacterial culture was transferred to 50% glycerol and stored at -80℃.

[0039] Screening of sodium nitrite-degrading strains: The preserved strains were activated and passaged to the third generation, then inoculated at a 2% inoculum into MRS liquid medium containing 150 mg / L sodium nitrite and incubated for 24 h. Subsequently, the absorbance of the cell-free supernatant was measured at 538 nm using a UV spectrophotometer via the naphthylethylenediamine hydrochloride method, and the sodium nitrite content was calculated according to the standard curve. The sodium nitrite degradation rate of the strains was calculated using the following formula.

[0040] .

[0041] C0 represents the sodium nitrite content in the initial culture medium, expressed in mg / L; C1 represents the sodium nitrite content in the culture medium after 24 hours of incubation, expressed in mg / L.

[0042] The results showed that sodium nitrite in the culture medium, under weakly acidic conditions, reacted with p-aminobenzenesulfonic acid, then with naphthylethylenediamine hydrochloride to form a purple-red azo compound. The intensity of the color was positively correlated with the sodium nitrite content within a certain range. The degradation results of sodium nitrite by different strains were as follows: Figure 1 As shown in the figure. LHZ4, which exhibits the strongest degradation effect on sodium nitrite, was selected for subsequent experiments.

[0043] 2. Identification and phylogenetic tree analysis of strain LHZ4.

[0044] (1) Colony morphology characteristics: The above-mentioned strain LHZ4 was streaked on MRS solid medium containing 1% calcium carbonate and incubated at 37℃ for 24h. The colonies were raised, with relatively rounded calcium dissolution zones, milky white in color, smooth and opaque surface, and neat edges. Figure 2 As shown; after Gram staining, the bacteria appear rod-shaped under an optical microscope. Figure 3 ).

[0045] (2) 16S rDNA sequence and phylogenetic tree analysis: DNA was extracted from the strain using a rapid extraction kit (B518225-0060, Sangon Biotech, Shanghai, China), and PCR amplification was performed using 27F and 1492R primers. The DNA amplification products were sequenced by Sangon Biotech Co., Ltd. (Shanghai, China), and the sequencing results were submitted to GenBank for BLAST comparative analysis.

[0046] The 16S rDNA gene sequence of the strain is as follows: CGAAGGGGCGGCTGCTATACATGCAAGTCGAACGAACTCTGGTATTGATTGGTGCTTGCATCATGATTTACATTTGAGTGAGTGGCGAACTGGTGAGTAACACGTGGGAAACCTGCCCAGAAGCGGGGGATAACACCTGGAAACAGATGCTAATACCGCATAACAACTTGGACCGCATGGTCCGAGTTTGAAAGATGGCTTCGGCTATCACTTTTGGATGGTCCCGCGGCGTATTAGCTAGATGGTGAGGTAACGGCTCACCATGGCAATGATACGTAGCCGACCTGAGAGGGTAATCGGCCACATTGGGACTGAGACACGGCCCAAACTCCTACGGGAGGCAGCAGTAGGGAATCTTCCACAATGGACGAAAGTCTGATGGAGCAACGCCGCGTGAGTGAAGAAGGGTTTCGGCTCGTAAAACTCTGTTGTTAAAGAAGAACATATCTGAGAGTAACTGTTCAGGTATTGACGGTATTTAACCAGAAAGCCACGGACATGGATACAGGTGGTGCATGGTTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTATTATCAGTTGCCAGCATTAAGTTGGGCACTCTGGTGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAATCATCATGCCCCTTATGACCTGGGCTACACACGTGCTACAATGGATGGTACAACGAGTTGCGAACTCGCGAGAGTAAGCTAATCTCTTAAAGCCATTCTCAGTTCGGATTGTAGGCTGCAACTCGCCTACATGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGAGAGTTTGTAACACCCAAAGTCGGTGGGGTAACCTTTTAGGAACCAGCCGCCTAAGGTGACAGAGTGG。

[0047] A comparison with the NCBI database (http: / / www.ncbi.nlm.nih.gov / ) revealed that the strain LHZ4 was similar to... L. plantarum They have excellent homology (>99%), and their phylogenetic tree is as follows: Figure 4 As shown. The classification obtained above is named... Lactibacillus plantarum LHZ4 of *Lactobacillus plantarum* was deposited on May 21, 2025, at the China General Microbiological Culture Collection Center, No. 3, No. 1, Beizhan West Road, Chaoyang District, Beijing, with accession number CGMCC NO: 34622.

[0048] Example 2: Hemolytic activity determination of strain LHZ4. The bacterial suspension, after 24 hours of incubation, was streaked onto Columbia blood agar plates containing 5% defibrinated sheep blood, with Staphylococcus aureus as a positive control. Observation was performed after incubation at 37°C for 48 hours. If the colony color turned grass green or dark green, it was α-hemolysis; if a clear transparent zone appeared around the colony, it was β-hemolysis; if neither of these conditions was observed, it was γ-hemolysis (i.e., no hemolysis).

[0049] The results are as follows Figure 5 As shown, strain LHZ4 does not possess hemolytic activity.

[0050] Example 3: Gelatinase activity assay of strain LHZ4. The bacterial suspension, after 24 hours of incubation, was inoculated into test tubes containing nutrient gelatin medium. Test tubes containing nutrient gelatin without bacterial suspension and test tubes containing nutrient gelatin inoculated with Staphylococcus aureus served as controls. After incubation at 37°C for 7 days, the test tubes were immersed in an ice bath for 15-30 minutes, and then the tubes were tilted to observe whether the gelatin underwent hydrolysis. If the gelatin underwent hydrolysis, it would become a liquid medium even when exposed to low temperature (ice bath), while the uninoculated control medium remained solid.

[0051] The results showed that strain LHZ4 did not possess gelatinase activity, such as Figure 6 As shown.

[0052] Example 4: DNase activity determination of strain LHZ4. The bacterial suspension, after 24 hours of incubation, was streaked onto a DNase agar plate. Staphylococcus aureus was used as a positive control. After incubation at 37°C for 48 hours, 1 mol / L hydrochloric acid was added, and the formation of a clear zone was observed. The appearance of a clear zone around the strain indicated positive DNase activity; conversely, the absence of a clear zone indicated negative DNase activity.

[0053] The results showed that strain LHZ4 did not possess DNase activity, such as Figure 7 As shown.

[0054] Example 5: Analysis of the extreme environment tolerance of strain LHZ4.

[0055] To better investigate the potential of strain LHZ4 obtained in Example 1 as a probiotic starter, the tolerance of strain LHZ4 to acids (pH 2.5, 3, 4) as well as to phenol and lysozyme was studied.

[0056] After activation, strain LHZ4 obtained in Example 1 was passaged to the third generation and then inoculated into MRS broth at pH 2.5, 3, and 4 at a 2% inoculum size. The OD 600nm Turbidity was measured at 0h and 4h and survival rate was calculated. Similarly, the strain was inoculated at 2% into MRS liquid medium containing 0.4% phenol and electrolyte solution prepared with lysozyme and incubated for 24h and 48h respectively. The number of viable bacteria was determined by plate counting and survival rate was calculated.

[0057] Experimental results showed that strain LHZ4 exhibited good survival rates under acidic conditions at pH 2.5, pH 3, and pH 4, at 68.76% ± 0.26%, 77.58% ± 0.24%, and 81.22% ± 0.20%, respectively. It also showed good survival rates under conditions containing lysozyme and phenol, at 94.33% ± 3.50% and 96.92% ± 0.49%, respectively, demonstrating good tolerance to extreme environments. Figure 8 ).

[0058] Example 6: Strain LHZ4's effects on DPPH free radicals and ABTS + Analysis of the scavenging capacity of free radicals, hydroxyl radicals and superoxide anion radicals.

[0059] The suspension of strain LHZ4 was centrifuged at 8000×g for 10 min at 4°C to collect the cell-free supernatant, which was used to prepare a solution for the determination of DPPH free radicals and ABTS. + The sample was used to determine its ability to scavenge free radicals, hydroxyl radicals, and superoxide anion radicals.

[0060] To determine the DPPH free radical scavenging ability, 1 mL of cell-free supernatant from lactic acid bacteria was first placed in a 5 mL centrifuge tube, followed by the addition of an equal volume of 0.2 mmol / L DPPH-anhydrous ethanol solution, and vortexed for 20 s. The reaction was then carried out at 37 °C in the dark for 30 min. After the reaction was complete, the absorbance was measured at 517 nm using a UV spectrophotometer. The DPPH free radical scavenging ability of strain LHZ4 was calculated based on the following results.

[0061] .

[0062] A s It is the absorbance of the experimental group, A c The absorbance is for the control group.

[0063] For ABTS +The determination of free radical scavenging ability involved using 7 mM ABTS. + ABTS is formed by mixing with 2.45 mM potassium persulfate (1:1 v / v). + The solution was reacted at room temperature in the dark for 24 hours to prepare the free radical cations required for the experiment. After the reaction was completed, the ABTS was adjusted at a wavelength of 734 nm. ＋ The absorbance of the solution was 0.700 ± 0.02. Subsequently, 500 μL of the sample and 1000 μL of ABTS were mixed. ＋ The solutions were mixed and incubated at room temperature for 10 min. The absorbance was measured at 734 nm using a UV spectrophotometer. The effect of strain LHZ4 on ABTS was calculated using the following formula. + Free radical scavenging ability.

[0064] .

[0065] A s It is the absorbance of the experimental group, A c The absorbance is for the control group.

[0066] To determine the scavenging ability of superoxide anion radicals, superoxide anion radicals were prepared by auto-oxidation of pyrogallic acid under alkaline conditions. 100 μL of the sample solution was mixed with 4.5 mL of Tris-HCl solution (0.05 mol / L, pH 8.2) and incubated in a water bath at 25 °C for 20 min. Subsequently, 0.4 mL of pyrogallic acid (0.25 mol / L, preheated to 25 °C) was added, and the mixture was incubated at 25 °C for 4 min. The reaction was terminated by adding 0.1 mL of 8 mol / L HCl. The absorbance was measured at 320 nm using a UV spectrophotometer. The scavenging ability of strain LHZ4 against superoxide anion radicals was calculated using the following formula.

[0067] .

[0068] A s It is the absorbance of the experimental group, A c The absorbance is for the control group.

[0069] To determine the scavenging ability of hydroxyl radicals, hydroxyl radicals were first generated in a mixture of 0.5 mL of 9 mM FeSO4 and 0.5 mL of 8.8 mmol / L H2O2. Then, 0.5 mL of 9 mM salicylic acid and 0.5 mL of lactic acid bacteria fermentation supernatant or cell lysate were added. The mixture was incubated at 37 °C for 30 min, and the absorbance was measured at 510 nm using a UV spectrophotometer. The scavenging ability of strain LHZ4 against hydroxyl radicals was calculated using the following formula.

[0070] .

[0071] In the formula: As is the absorbance of the experimental group; A's is the absorbance of the control group; Ac is the absorbance of the blank group.

[0072] Experimental results showed that strain LHZ4 exhibited certain scavenging abilities against DPPH free radicals, ABTS free radicals, hydroxyl free radicals, and superoxide anions, demonstrating good antioxidant capacity, with scavenging rates of 28.26%±3.22%, 95.33%±0.22%, 96.74±0.07%, and 52.10%±1.73%, respectively. Figure 9 ).

[0073] Example 7: Analysis of the self-aggregation ability of strain LHZ4.

[0074] First, strain LHZ4 was washed twice with PBS buffer (pH 7.2 ± 0.2) and then resuspended in PBS. At OD... 600nm The bacterial concentration was adjusted to 0.8 ± 0.02 for subsequent experiments. 4 mL of bacterial culture was vortexed for 10 s and incubated at 37°C. Every 3, 6, 9, and 24 hours, 0.1 mL of the supernatant was transferred to 3.9 mL of PBS (pH 7.2 ± 0.2), mixed thoroughly, and the absorbance was measured at 600 nm using a UV spectrophotometer. The scavenging ability of strain LHZ4 against hydroxyl radicals was calculated using the following formula.

[0075] .

[0076] In the formula: A0 is the absorbance at 0h, and A1 is the absorbance at each sampling time point (4h, 6h, 9h, 24h).

[0077] Experimental results show that it has good self-aggregation ability, with self-aggregation rates of 18.23±5.06%, 26.70±1.48%, 39.61±5.32%, and 67.48±5.55% at 4, 6, 9, and 24 hours, respectively. Figure 10 As shown.

[0078] Example 8: Adhesion of Caco-2 cells Caco-2 cells were cultured in 6-well plates of DMEM medium containing 10% heat-inactivated fetal bovine serum and double antibiotics (100 U / mL penicillin and 100 U / mL streptomycin). The culture flasks were placed in an incubator at 37°C with 5% CO2 for 96 h. After the cells adhered and grew to a monolayer, adhesion experiments were performed. The bacterial cells were collected by centrifugation at 8000 × g for 10 min at 4°C, washed three times with PBS buffer (pH 7.2 ± 0.02), and then cultured at OD0.05. 600nmAfter adjusting the bacterial density to 0.8±0.02, the cells were co-incubated with the cultured Caco-2 for 2 hours. The incubation solution was then aspirated and the cells were washed twice. The cells were fixed with 5% methanol, stained with 0.5% crystal violet for 1 minute after 0.5 min, and then destained. After standing and drying, the adhesion of the bacterial strains was observed under an oil immersion microscope at 100×.

[0079] The results showed that ( Figure 11 LHZ4 has a certain adhesion ability to Caco-2 cells.

[0080] Example 9: Degradation ability of strain LHZ4 for sodium nitrite of different concentrations.

[0081] strain LHZ4 was used at 2% (1×10) 6 Inoculate the medium with CFU / mL into MRS broth at sodium nitrite concentrations of 0, 2.5, 5, 7.5, 10, and 12.5 mmol / L, and incubate at 37°C for 36 h. Take samples at 6, 12, 24, and 36 h to determine the nitrite concentration.

[0082] Experimental results showed that strain LHZ4 could significantly degrade sodium nitrite, reaching degradation rates of 99.96%±1.20%, 99.82%±0.12%, 97.97%±0.37%, 96.77%±0.26%, and 95.46%±0.11% with increasing incubation time, respectively. It exhibited good degradation performance for all concentrations of sodium nitrite, with degradation rates all >95.00%. Figure 12 As shown.

[0083] Example 10: Effect of strain LHZ4 on fermented white radish.

[0084] After culturing strain LHZ4 to the logarithmic growth phase, the bacterial cells were collected by centrifugation at 8000×g at 4℃. The cells were washed twice with PBS buffer (pH 7.0±0.2) to completely remove the culture medium. White radishes were washed, peeled, and cut into strips of 2×5×2cm. They were soaked in 3% saline solution for 4 hours, rinsed with clean water, and placed in a fermentation tank that had been pre-boiled. The radish strips were submerged in 3% saline solution. The lactic acid bacteria from the previous step were then inoculated at a 2% inoculum (1×10⁻⁶). 6 The inoculum (CFU / mL) was injected into the fermentation radish jar. Anaerobic fermentation was carried out at 37℃ for 120 hours. Samples were taken every 24 hours to determine the sodium nitrite content, pH, and bacterial growth. After fermentation, an electronic nose was used to determine the volatile matter content of the fermented white radish. A strain of *Lactobacillus plantarum* SPC10 isolated from commercial kimchi was used as the starter culture, with natural fermentation serving as the positive control (SP10 group) and the blank control (CK group).

[0085] Experimental results show that the finished white radish products after 120 hours of fermentation in different groups are shown in the following images. Figure 13As shown in the figure, inoculation with *Lactobacillus plantarum* LHZ4 showed a stronger sodium nitrite degradation effect compared to inoculation with commercial *Lactobacillus plantarum* SPC10 and the CK group. Figure 14 a) shortened the fermentation time. At 24 h, the sodium nitrite content was 1.71 mg / mL ± 0.10 mg / mL, which was 80.58 mg / mL ± 1.90 mg / mL lower than that of the CK group and the SPC10 inoculated group, and 6.86 mg / mL ± 0.08 mg / mL lower than that of the CK group and the SPC10 inoculated group, respectively. The pH of fermented white radish decreased overall with the extension of fermentation time. The pH reduction effect of inoculating with Lactobacillus plantarum LHZ4 was significantly greater than that of the commercial Lactobacillus plantarum SPC10 inoculated group and the CK group. Figure 14 (b) This may be related to the acid-producing performance of lactic acid bacteria and the content of lactic acid bacteria.

[0086] Furthermore, *Lactobacillus plantarum* LHZ4 showed better growth performance compared to the commercially inoculated *Lactobacillus plantarum* SPC10 and CK groups (Figure 1). Figure 14 c), which proves that it can be developed and utilized as an excellent fermenting agent.

[0087] The rich flavor of fermented kimchi is due to the synergistic fermentation process of the microbial community, as analyzed by electronic nose (…). Figure 14 d), the content of odor components inoculated with L. plant lactobacillus LHZ4 was higher than that inoculated with commercial L. plant lactobacillus SPC10.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A strain of *Lactobacillus plantarum* ( Lactobacillus plantarum LHZ4 is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO:34622.

2. A sodium nitrite degradation agent comprising Lactobacillus plantarum LHZ4 as described in claim 1.

3. The application of the sodium nitrite degrading agent according to claim 2 for degrading sodium nitrite in fermented white radish.

4. A fermenting agent comprising Lactobacillus plantarum LHZ4 as described in claim 1.

5. The use of the fermenting agent according to claim 4 in the preparation of fermented white radish products.

6. The use of the fermentation agent according to claim 4 in the preparation of fruit and vegetable enzyme products with low nitrite content.

7. A method for preparing fermented white radish, characterized in that: The fermenting agent according to claim 4 is used at 1×10 6 The inoculum was introduced into the white radish fermentation system at a concentration of CFU / mL and fermented anaerobically at 37℃ for 120 hours.

8. A fermented white radish product, prepared by the method described in claim 7.

9. The fermented white radish product as described in claim 8, characterized in that: The viable bacteria count reached 6.54 lg CFU / mL ± 0.09 lg CFU / mL, and the pH value was 3.31 ± 0.

01.

10. A probiotic preparation comprising *Lactobacillus plantarum* LHZ4 as described in claim 1, with a viable count ≥ 1 × 10⁻⁶. 9 CFU / mL; the formulation exhibits gastric acid tolerance and antioxidant properties.

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