Lactobacillus plantarum SN21 and application thereof
By screening and applying Lactobacillus plantarum SN21 for microbial fermentation of peanut protein and optimizing fermentation conditions, the problem of poor desensitization effect of peanut protein was solved, and rapid and effective desensitization and functional enhancement of peanut protein were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-10
AI Technical Summary
In existing technologies, desensitization methods for peanut protein often employ fermentation combined with other methods, and the fermentation time is relatively long. Lactic acid bacteria fermentation is not very effective in desensitizing peanut protein, making it difficult to effectively reduce its allergenicity.
A strain of Lactobacillus plantarum SN21 was screened and applied to the microbial fermentation of peanut protein. By optimizing the fermentation conditions, including fermentation time and inoculum size, the allergenicity of peanut protein was significantly reduced.
It significantly reduced the antigenicity of peanut protein by 62.29% and increased its antioxidant properties by 54.57% within 36 hours, while also improving solubility, emulsifying activity, and stability. Moreover, it is low in cost and suitable for the development of hypoallergenic and functional foods.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of microbial technology, specifically relating to a strain of Lactobacillus plantarum SN21 and its applications. Background Technology
[0002] Food allergy is an abnormal immune response of the body to specific food antigens. Depending on the formation and site of action of the bioactive mediators, allergic symptoms include allergic eczema, urticaria, allergic perioral and lip redness and swelling, abdominal pain and diarrhea, etc. In severe cases, it can cause difficulty breathing, or even anaphylactic shock and death. Therefore, food allergy is considered an important issue of widespread concern in the fields of food science and public health.
[0003] Peanut allergy is one of the more common food allergies. Currently, the main methods to reduce peanut allergenicity are avoiding the intake of allergenic foods and food processing techniques. Peanuts contain 24% to 36% protein, and peanut protein is rich in amino acids, including all eight essential amino acids required by the human body. However, peanut protein is an important food allergen. If food processing techniques can be used to reduce or eliminate peanut protein allergens, the amino acid source for people with peanut allergies can be enriched.
[0004] Compared to desensitization methods such as irradiation, high-pressure steam, and enzymatic hydrolysis, microbial fermentation is a green, safe, and low-cost method. The impact of fermentation on food allergenicity depends on the microbial strain, fermentation time, and inoculum size; selecting appropriate fermentation conditions is crucial for reducing food allergenicity. Seo et al. found that solid-state fermentation of soybean meal with Bacillus subtilis for 24 hours reduced the allergenicity of the soybean meal (Seo SH, Cho S J. Changes in allergenic and antinutritional protein profiles of soybean meal during solid-state fermentation with...). Bacillus subtilis [J]. LWT-Food Science and Technology, 2016, 70: 208-212. She Xuanming studied the effect of yeast fermentation on the allergenicity of buckwheat sourdough, and the results showed that fermentation for 12-16 h significantly reduced the allergenicity of buckwheat (She Xuanming. Study on the changing patterns and mechanisms of buckwheat protein allergens during fermentation [D]. Shanghai: Shanghai University of Applied Technology, 2022). Wroblewska et al. found that Lactobacillus casei fermentation of milk protein can significantly reduce the immunoreactivity and allergenicity of whey protein (Wroblewska B, Markiewicz LH, Szyc AM, et al.). Lactobacillus caseiLcY decreases milk protein immunoreactivity offered buttermilk but also contains IgE-reactive proteins [J]. FoodResearch International, 2016, 83: 95-101).
[0005] Regarding the desensitization of peanut protein through fermentation, existing technologies include: some using Bacillus subtilis to ferment peanut protein (Zhou Yang. Study on the Influence of Microbial Fermentation on Allergenic Factors in Peanut Protein [D]. Zhengzhou: Henan University of Technology, 2014); some using far-infrared irradiation of peanut protein solution followed by fermentation to reduce the allergenicity of peanut protein (Yao Jiangang, Mu Shuqi, Zhang Chunpeng, Liu Huan, Li Zhi. A Method for Preparing Low-Allergenic Peanut Protein Peptides [P]. China, ZL202411793337.2, 2025-02-28); and some using high-pressure steam and microbial fermentation technology to prepare low-allergenic peanut protein powder (Liu Shaowei, Zhou Dingpeng, Na Yintu, Su Fugong. A Method for Preparing Low-Allergenic Peanut Protein Powder by High-Pressure Steam and Microbial Fermentation [P]. China, CN202110563595.1, 2021-08-31). Most of these technologies use fermentation combined with other methods to reduce the allergenicity of peanut protein, and the fermentation time is relatively long (48 h~72 h).
[0006] Lactic acid bacteria, as the most commonly used probiotics in fermented foods, possess various beneficial functions. While there is some research on using lactic acid bacteria fermentation to reduce peanut protein allergens (Pi XW, Fu GM, Yang YL, et al. Changes in IgE binding capacity, structure, physicochemical properties of peanuts throughfermentation with...),... Bacillus natto and Lactobacillus plantarum Along with autoclavepretreatment [J]. Food Chemistry, 2022, 392:133208), but its desensitization effect was not good (antigenicity decreased by 20.6%). Therefore, screening and identifying lactic acid bacteria that can reduce peanut allergenicity is of great significance. Summary of the Invention
[0007] To address the issue of how to reduce the allergenicity of peanut protein using safe and environmentally friendly processing methods, this invention screened a strain of Lactobacillus plantarum SN21 and applied it to the desensitization of peanut protein.
[0008] The present invention specifically adopts the following technical solution: In a first aspect, the present invention provides a strain of *Lactobacillus plantarum* SN21, wherein *Lactobacillus plantarum* SN21 is classified as... Lactobacillus planturum It was deposited on September 22, 2025 at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCC NO: M20252076.
[0009] The 16S rDNA sequence of Lactobacillus plantarum SN21 is shown in SEQ ID NO:1.
[0010] Secondly, the present invention provides a microbial inoculant containing *Lactobacillus plantarum* SN21. Further, the microbial inoculant contains fermentation broth or dried powder of *Lactobacillus plantarum* SN21.
[0011] Furthermore, the fermentation broth is a fermentation culture medium, and the preparation method of the fermentation culture medium includes the following steps: Lactobacillus plantarum SN21 was inoculated into MRS liquid medium and cultured at 37 °C for 24 h.
[0012] Furthermore, the fermentation broth is a fermentation supernatant or a bacterial suspension. The fermentation supernatant is obtained by centrifuging the fermentation culture broth; the bacterial suspension is obtained by resuspending the precipitate after centrifugation of the fermentation culture broth.
[0013] Furthermore, the dried bacterial powder is a freeze-dried powder.
[0014] Thirdly, the present invention provides the use of one or more of the following components in the preparation of low-allergenic peanut protein products: (1) The Lactobacillus plantarum SN21; (2) The fermentation broth or dried powder of Lactobacillus plantarum SN21; (3) The microbial agent mentioned above.
[0015] The application includes adding the Lactobacillus plantarum SN21, the fermentation broth or dried powder of Lactobacillus plantarum SN21, and / or the microbial agent to a reaction system containing peanut protein products for fermentation, so as to reduce the allergenicity of peanut protein.
[0016] In one embodiment of the present invention, the product includes, but is not limited to, peanut milk, peanut powder, and other foods and beverages containing peanut protein.
[0017] In one embodiment of the present invention, the fermentation broth of *Lactobacillus plantarum* SN21 is added to a solution containing peanut protein for liquid fermentation. The fermentation broth is a bacterial suspension with a concentration of 2.8 × 10⁻⁶. 7 CFU / mL.
[0018] In one embodiment of the present invention, the inoculum amount of *Lactobacillus plantarum* SN21 fermentation broth in the peanut protein-containing solution is 4%–12% v / v, preferably 6% v / v. The peanut protein-containing solution is prepared by adding peanut protein to a 0.5% NaCl solution, and the ratio of peanut protein to 0.5% NaCl solution is 1 g:(5–25) mL, preferably 1 g:15 mL. In one embodiment of the present invention, the liquid fermentation time is 24 h–72 h, preferably 36 h.
[0019] Fourthly, the present invention also provides a fermented peanut protein, which is obtained by the following steps: (1) Inoculate Lactobacillus plantarum SN21 into a product containing peanut protein and ferment at 37 °C.
[0020] (2) The fermented peanut protein sample was freeze-dried, crushed and sieved to obtain fermented peanut protein.
[0021] The beneficial effects of this invention are as follows: (1) This invention uses peanut protein as raw material and uses activated and expanded cultured Lactobacillus plantarum SN21 for fermentation. The optimal liquid fermentation conditions for peanut protein were determined. Under these conditions, peanut protein allergens were destroyed and the antigenicity of fermented peanut protein was significantly reduced. Compared with unfermented peanut protein, the antigenicity was reduced by 62.29%.
[0022] (2) The antioxidant properties of peanut protein samples fermented under optimal liquid fermentation conditions were determined. The results showed that the antioxidant properties of fermented peanut protein increased, and the DPPH free radical scavenging ability was increased by 54.57% compared with unfermented peanut protein.
[0023] (3) The present invention measures the solubility and emulsification properties of peanut protein samples after fermentation under optimal liquid fermentation conditions. The results show that the solubility, emulsification activity and emulsification stability of fermented peanut protein are also improved, by 78.96%, 22.70% and 26.32%, respectively.
[0024] (4) The use of Lactobacillus plantarum SN21 to ferment peanut protein in this invention can not only effectively reduce its allergenicity, but also the Lactobacillus plantarum used is a probiotic that can regulate the intestinal flora and improve the health of the host. In other words, this invention can enhance the functional characteristics of the product while desensitizing it, and is suitable for the development of hypoallergenic foods and functional foods.
[0025] (5) Compared with the use of fermentation combined with other methods to reduce the allergenicity of peanut protein, the present invention uses a single Lactobacillus plantarum to ferment peanut protein, and the fermentation time of the Lactobacillus plantarum used for peanut protein is significantly shortened (36 h), which is more conducive to practical application and saves costs. Attached Figure Description
[0026] Figure 1 This is a colony morphology diagram of Lactobacillus plantarum SN21; Figure 2 This is a Gram-stained microscopic image of Lactobacillus plantarum SN21. Figure 3 It is a phylogenetic tree of Lactobacillus plantarum SN21; Figure 4 This is a comparison chart of the antigenicity of peanut protein fermented by Lactobacillus plantarum SN21 and commercially available Lactobacillus plantarum.
[0027] Preservation Information Preserved biological material: Lactobacillus plantarum SN21; Accession number: CCTCC NO: M20252076; Category Naming: Lactobacillus planturum SN21 ; Depository: China Center for Type Culture Collection; Address of the depositary institution: Wuhan University, Wuhan, China; Preservation date: September 22, 2025. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0029] Example 1 (1) Isolation and screening of strains Five mL of naturally fermented milk sample was added to 45 mL of 0.85% sterile physiological saline and shaken for 1 h. The sample was then diluted using a tenfold gradient method. Different dilutions were spread onto MRS solid medium containing 3% CaCO3 and incubated upside down at 37 ℃ for 36 h until a large number of colonies formed on the surface of the medium. After colony formation, strains with different colony morphologies exhibiting calcium dissolution zones were selected and streaked onto MRS solid medium and incubated upside down at 37 ℃ for 36 h. This streaking was repeated five times to obtain the purified strain SN21.
[0030] (2) Identification of strains ① Gram staining and microscopic examination The purified strain from (1) was inoculated onto MRS solid medium and streaked. Colony morphology was observed. On MRS solid medium, colonies were milky white, round, with smooth, regular edges, and opaque. Figure 1 As shown.
[0031] Single colonies were picked and streaked to isolate pure cultures of the bacterial strain. Colony morphology and microscopic examination results are as follows: Figure 2 As shown, the strain is a Gram-positive bacterium, short rod-shaped.
[0032] ② 16S rDNA identification and phylogenetic tree construction Genomic DNA of strain SN21 was extracted according to the instructions of the bacterial genomic DNA extraction kit (Tiangen Biotech (Beijing) Co., Ltd.). 16S rDNA was amplified using universal bacterial primers: forward primer 27F and reverse primer 1492R. The PCR amplification program was as follows: 95 ℃ pre-denaturation for 10 min, 35 cycles (95 ℃ denaturation for 15 s, 54 ℃ annealing for 15 s, 72 ℃ extension for 1 min, 72 ℃ stable extension for 5 min), and finally stored at 4 ℃. The amplified product was sent to Sangon Biotech (Shanghai) Co., Ltd. for sequencing. The sequence of the 16S rDNA of strain SN21 is shown in SEQ ID NO:1, specifically:
[0033] The 16S rDNA sequencing results of strain SN21 were compared with the NCBI database using BLAST, and a phylogenetic tree was constructed using MEGA X software to classify and identify the strain. The constructed phylogenetic tree is shown below. Figure 3 As shown.
[0034] Based on the comparison results of the phylogenetic trees, the screened strain SN21 is similar to *Lactobacillus plantarum* (…). Lactobacillus planturum The similarity was 99.38%. Therefore, the strain SN21 screened in this embodiment can be identified as Lactobacillus plantarum.
[0035] This strain SN21 was deposited at the China Center for Type Culture Collection (CCTCC) on September 22, 2025, with accession number CCTCC NO: M20252076. Its classification and nomenclature are as follows: Lactobacillus planturum .
[0036] Example 2 (1) Preparation of Lactobacillus plantarum SN21 bacterial suspension A single colony of *Lactobacillus plantarum* SN21 was picked and placed in 10 mL of MRS liquid medium, and fermented for 24 h in a constant temperature incubator at 37 ℃ and 80% humidity. 0.2 mL of the activated bacterial suspension was then transferred to a fresh 10 mL of MRS liquid medium and cultured. This process was repeated three times. After centrifugation, the precipitate was reconstituted with sterile physiological saline, resulting in a bacterial suspension with a concentration of 2.8 × 10⁻⁶. 7 CFU / mL.
[0037] (2) Peanut protein fermented by Lactobacillus plantarum SN21 5 g of peanut protein (purchased from Anyang Tianxiangrui Food Technology Co., Ltd.) was weighed into a 250 mL Erlenmeyer flask, and 75 mL of 0.5% NaCl solution was added. The mixture was sterilized at 121 °C for 20 min, cooled to room temperature, and then inoculated with the *Lactobacillus plantarum* SN21 bacterial suspension prepared in step (1). The mixture was fermented in a constant temperature incubator at 37 °C and 80% humidity for 48 h. After fermentation, the product was freeze-dried to obtain fermented peanut protein. The inoculation amounts of the *Lactobacillus plantarum* SN21 bacterial suspension were 4% v / v, 6% v / v, 8% v / v, 10% v / v, and 12% v / v, respectively.
[0038] Regarding the antigenicity of peanut protein, the indirect competitive ELISA method showed that when the inoculum amount of Lactobacillus plantarum SN21 was 6% v / v, the antigenicity of fermented peanut protein decreased the most compared with that of unfermented peanut protein, specifically by 60.05%.
[0039] Regarding the antioxidant properties of peanut protein, when the inoculum amount of Lactobacillus plantarum SN21 was 6% v / v, the DPPH free radical scavenging rate of fermented peanut protein was increased by 52.94% compared with that of unfermented peanut protein.
[0040] Regarding peanut protein solubility, when the inoculum amount of Lactobacillus plantarum SN21 was 6% v / v, the solubility of fermented peanut protein was increased by 77.05% compared with that of unfermented peanut protein.
[0041] Regarding the emulsifying activity and emulsifying stability of peanut protein, when the inoculum amount of Lactobacillus plantarum SN21 was 6% v / v, the emulsifying activity of fermented peanut protein was increased by 21.01% compared with that of unfermented peanut protein, and the emulsifying stability of fermented peanut protein was increased by 22.84% compared with that of unfermented peanut protein.
[0042] Example 3 5 g of peanut protein was weighed into a 250 mL Erlenmeyer flask, and 75 mL of 0.5% NaCl solution was added. The flask was sterilized at 121 °C for 20 min, cooled to room temperature, and then inoculated with an 8% v / v *Lactobacillus plantarum* SN21 suspension prepared in Example 2. Fermentation was carried out in a constant temperature incubator at 37 °C and 80% humidity. After fermentation, the product was freeze-dried to obtain fermented peanut protein. The fermentation times were 24 h, 36 h, 48 h, 60 h, and 72 h, respectively.
[0043] Regarding the antigenicity of peanut protein, the indirect competitive ELISA method showed that when the fermentation time of Lactobacillus plantarum SN21 was 36 h, the antigenicity of fermented peanut protein decreased the most compared with that of unfermented peanut protein, specifically by 57.72%.
[0044] Regarding the antioxidant properties of peanut protein, when the fermentation time of Lactobacillus plantarum SN21 was 36 h, the DPPH free radical scavenging rate of fermented peanut protein was increased by 51.45% compared with that of unfermented peanut protein.
[0045] Regarding peanut protein solubility, when the fermentation time of Lactobacillus plantarum SN21 was 36 h, the solubility of fermented peanut protein increased by 76.52% compared with that of unfermented peanut protein.
[0046] Regarding the emulsifying activity and emulsifying stability of peanut protein, when the fermentation time of Lactobacillus plantarum SN21 was 36 h, the emulsifying activity of fermented peanut protein was increased by 21.44% compared with that of unfermented peanut protein, and the emulsifying stability of fermented peanut protein was increased by 25.37% compared with that of unfermented peanut protein.
[0047] Example 4 Weigh 5 g of peanut protein into a 250 mL Erlenmeyer flask, add a certain amount of 0.5% NaCl solution, sterilize at 121 ℃ for 20 min, cool to room temperature, and then inoculate with 8% v / v *Lactobacillus plantarum* SN21 bacterial suspension prepared in Example 2. Ferment in a constant temperature incubator at 37 ℃ and 80% humidity for 48 h. After fermentation, freeze-dry the product to obtain fermented peanut protein. The material-to-liquid ratio of peanut protein to 0.5% NaCl solution is 1 g: 5 mL, 1 g: 10 mL, 1 g: 15 mL, 1 g: 20 mL, and 1 g: 25 mL, respectively.
[0048] Regarding the antigenicity of peanut protein, the indirect competitive ELISA method showed that when the ratio of peanut protein to 0.5% NaCl solution was 1 g:15 mL, the antigenicity of fermented peanut protein decreased the most compared with that of unfermented peanut protein, specifically by 55.41%.
[0049] Regarding the antioxidant properties of peanut protein, when the ratio of peanut protein to 0.5% NaCl solution was 1 g: 15 mL, the DPPH free radical scavenging rate of fermented peanut protein was 53.29% higher than that of unfermented peanut protein.
[0050] Regarding the solubility of peanut protein, when the ratio of peanut protein to 0.5% NaCl solution is 1 g: 15 mL, the solubility of fermented peanut protein is increased by 78.35% compared with that of unfermented peanut protein.
[0051] Regarding the emulsifying activity and emulsifying stability of peanut protein, when the ratio of peanut protein to 0.5% NaCl solution was 1g:15mL, the emulsifying activity of fermented peanut protein was increased by 19.24% compared with that of unfermented peanut protein, and the emulsifying stability of fermented peanut protein was increased by 21.42% compared with that of unfermented peanut protein.
[0052] Example 5 Weigh 5 g of peanut protein into a 250 mL Erlenmeyer flask, add 75 mL of 0.5% NaCl solution, sterilize at 121 °C for 20 min, cool to room temperature, and inoculate with the Lactobacillus plantarum SN21 bacterial suspension prepared in Example 2 at a 6% v / v inoculation rate. Ferment in a constant temperature incubator at 37 °C and 80% humidity for 36 h. After fermentation, freeze-dry the product to obtain fermented peanut protein.
[0053] Regarding the antigenicity of peanut protein, the antigenicity of fermented peanut protein was reduced by 62.29% compared with that of unfermented peanut protein, as determined by indirect competitive ELISA.
[0054] Regarding the antioxidant properties of peanut protein, fermented peanut protein showed a 54.57% higher DPPH free radical scavenging rate compared to unfermented peanut protein.
[0055] Regarding peanut protein solubility, fermented peanut protein showed a 78.96% increase in solubility compared to unfermented peanut protein.
[0056] Regarding the emulsifying activity and emulsifying stability of peanut protein, fermented peanut protein showed a 22.70% increase in emulsifying activity and a 26.32% increase in emulsifying stability compared to unfermented peanut protein.
[0057] Comparative Example 1 To compare the effects of the *Lactobacillus plantarum* used in this invention and commercially available *Lactobacillus plantarum* on peanut protein, the following experiment was conducted.
[0058] Weigh 5 g of peanut protein into a 250 mL Erlenmeyer flask, add 75 mL of 0.5% NaCl solution, sterilize at 121 ℃ for 20 min, cool to room temperature, and then inoculate with a commercially available *Lactobacillus plantarum* suspension (purchased from the China Industrial Microbial Culture Collection Center, accession number CICC 22210) at a 6% v / v inoculation rate (2.8 × 10⁻⁶). 7 Fermented peanut protein (CFU / mL) was fermented in a constant temperature incubator at 37 ℃ and 80% humidity for 36 h. After fermentation, the product was freeze-dried to obtain fermented peanut protein.
[0059] Regarding the antigenicity of peanut protein, the indirect competitive ELISA method showed that peanut protein fermented with commercially available *Lactobacillus plantarum* had a 38.97% lower antigenicity compared to unfermented peanut protein; in Example 5, peanut protein fermented with *Lactobacillus plantarum* SN21 had a 38.41% lower antigenicity compared to commercially available *Lactobacillus plantarum*-fermented peanut protein. Figure 4 As shown.
[0060] Regarding the antioxidant properties of peanut protein, peanut protein fermented with commercially available Lactobacillus plantarum showed a 47.81% higher DPPH free radical scavenging rate compared to unfermented peanut protein; in Example 5, peanut protein fermented with Lactobacillus plantarum SN21 showed a 12.95% higher DPPH free radical scavenging rate compared to commercially available Lactobacillus plantarum-fermented peanut protein.
[0061] Regarding the solubility of peanut protein, the solubility of peanut protein fermented with commercially available Lactobacillus plantarum was increased by 76.08% compared with that of unfermented peanut protein; in Example 5, the solubility of peanut protein fermented with Lactobacillus plantarum SN21 was increased by 12.05% compared with that of peanut protein fermented with commercially available Lactobacillus plantarum.
[0062] Regarding the emulsifying activity and emulsifying stability of peanut protein, peanut protein fermented with commercially available Lactobacillus plantarum showed an increase of 14.25% and 20.81% in emulsifying activity and emulsifying stability, respectively, compared with unfermented peanut protein. In Example 5, peanut protein fermented with Lactobacillus plantarum SN21 showed an increase of 9.85% and 6.96% in emulsifying activity and emulsifying stability, respectively, compared with commercially available Lactobacillus plantarum fermented peanut protein.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A strain of *Lactobacillus plantarum* SN21, characterized in that, The classification name of Lactobacillus plantarum SN21 is... Lactobacillus planturum The accession number is: CCTCC NO: M20252076.
2. A microbial inoculant, characterized in that, The microbial agent contains Lactobacillus plantarum SN21.
3. The microbial inoculant according to claim 2, characterized in that, The microbial agent contains the fermentation broth or dried powder of Lactobacillus plantarum SN21.
4. The microbial inoculant according to claim 3, characterized in that, The fermentation broth is a fermentation culture medium, and the preparation method of the fermentation culture medium includes the following steps: inoculating Lactobacillus plantarum SN21 into MRS liquid culture medium and culturing it at 37 ℃.
5. A microbial inoculant according to claim 3, characterized in that, The fermentation broth is either a fermentation supernatant or a bacterial suspension. The fermentation supernatant is obtained by centrifuging the fermentation culture broth. The bacterial suspension is obtained by resuspending the precipitate after centrifuging the fermentation culture broth.
6. The application of one or more of the following components in the preparation of low-allergenic peanut protein products, characterized in that, (1) The *Lactobacillus plantarum* SN21 as described in claim 1; (2) The fermentation broth or dried powder of Lactobacillus plantarum SN21 as described in claim 1; (3) The microbial agent according to any one of claims 2-5.
7. The application according to claim 6, characterized in that, The application includes adding the Lactobacillus plantarum SN21 of claim 1, the fermentation broth or dried powder of Lactobacillus plantarum SN21 of claim 1, and / or the microbial agent of any one of claims 2-5 to a reaction system containing peanut protein products for fermentation, so as to reduce the allergenicity of peanut protein.
8. The application according to claim 7, characterized in that, The fermentation broth of *Lactobacillus plantarum* SN21 was added to a solution containing peanut protein for liquid fermentation. The fermentation broth was a bacterial suspension with a concentration of 2.8 × 10⁻⁶. 7 The inoculum of Lactobacillus plantarum SN21 fermentation broth in a solution containing peanut protein was 4%~12% v / v.
9. The application according to claim 8, characterized in that, The solution containing peanut protein is prepared by adding peanut protein to a 0.5% NaCl solution, wherein the ratio of peanut protein to 0.5% NaCl solution is 1 g: (5~25) mL.
10. A fermented peanut protein, characterized in that, The fermented peanut protein was obtained according to the following steps: (1) Inoculate the Lactobacillus plantarum SN21 of claim 1 into a product containing peanut protein and ferment at 37 °C; (2) The fermented peanut protein sample was freeze-dried, crushed and sieved to obtain fermented peanut protein.