Pediococcus acidilactici and application thereof

Abstract

The invention discloses pediococcus acidilactici and application thereof, and relates to the technical field of microorganisms. The pediococcus acidilactici is pediococcus acidilactici Mei.1103.1, the preservation unit is China General Microbiological Culture Collection Center, the preservation number is CGMCC NO.32564, the preservation date is November 11, 2024, the preservation address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, No.1 Yard, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC NO.32564. The pediococcus acidilactici Mei.1103.1 is CGMCC NO.32564. The pediococcus acidilactici Mei.1103.1. The invention also provides application of the fermented dry rice flour in preparation of products for reducing uric acid, preventing / treating hyperuricemia, regulating immunity, preventing / treating kidney injury and preventing / treating fatty liver and fermented dry rice flour. The bacterium can reduce uric acid and relieve hyperuricemia; regulating blood fat; kidney and liver injuries caused by hyperuricemia are repaired; the content of volatile flavor compounds in the fermented dry rice flour is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and particularly relates to a Pediococcus acidilactici and its application. Background Art

[0002] Hyperuricemia (HUA) is a metabolic disease caused by excessive uric acid production or impaired uric acid excretion. Its main causes include purine metabolism disorders, renal insufficiency or genetic factors. Clinically, hyperuricemia is usually diagnosed by detecting the fasting serum uric acid level of patients. If the fasting serum uric acid level measured on different days regardless of gender exceeds 420 μmol / L, hyperuricemia can be diagnosed. Hyperuricemia can progress from early benign asymptomatic hyperuricemia to more severe chronic gouty arthritis and may ultimately lead to diseases such as renal failure, hypertension, hyperlipidemia, type 2 diabetes, and cardiovascular atherosclerosis.

[0003] In recent years, with the improvement of living standards and the changes in diet and lifestyle, the prevalence of hyperuricemia has increased significantly worldwide. Currently, drug treatment and dietary intervention are the two main treatment strategies for hyperuricemia. Although drugs have alleviated hyperuricemia to a certain extent, some of these drugs are expensive and may cause some serious side effects. In addition, about half of asymptomatic hyperuricemia will not eventually develop into gout, which makes many patients resistant to drug treatment. Dietary intervention has a greater impact on the quality of life of patients. In recent years, researchers have begun to explore non-drug uric acid-lowering treatment methods, including lactic acid bacteria, plant extracts, dietary fiber, oligopeptides, etc., in order to provide a mild, non-toxic and effective treatment means for hyperuricemia patients. Compared with traditional drug treatment, lactic acid bacteria, as a natural microorganism, have the advantages of safety, independence, and no side effects, and thus have received increasing attention from researchers.

[0004] Rice noodles, as a popular traditional food, have a huge consumer market in China and even globally. The traditional production process of rice noodles mainly uses early indica rice with high amylose content as the raw material, rather than late indica rice with high amylopectin content and more flavors, which makes the flavor of rice noodles have certain limitations and is difficult to meet the increasingly diverse and high-quality needs of consumers. In the food field, microbial fermentation technology has been widely used in improving food quality, increasing flavor substances, etc. Through microbial fermentation, macromolecular substances in raw materials can be decomposed and transformed to produce a variety of volatile flavor compounds, bringing unique flavors to food. In some dry-cured meat products, such as fish and goose, the action of microorganisms makes them rich in aliphatic unsaturated aldehydes with a carbon chain length of C6-C12, enhancing their fragrance. However, in the existing fermentation rice noodle preparation technology, the fermentation time is relatively short, and the volatile aldehyde substances produced are mainly saturated aldehydes, whose flavor thresholds are often higher than those of unsaturated aldehydes, resulting in a less intense flavor of rice noodles. And during the natural fermentation process, the microbial community structure changes greatly, and it is easy to be infected by miscellaneous bacteria, making the flavor and quality of rice noodles unstable. Strain purification fermentation is an idea to solve this problem. However, the existing fermentation strains used are difficult to efficiently produce aliphatic unsaturated aldehydes with a carbon chain length of C6-C12, such as substances with grassy, fatty, and fruity aromas like trans-2-decenal and 2-undecenal. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and provide a Pediococcus acidilactici and its application, specifically a Pediococcus acidilactici Mei.1103.1 with the effects of degrading nucleosides, reducing uric acid, alleviating hyperuricemia, immunomodulation, preventing / treating kidney injury, preventing / treating fatty liver, and being able to be used for preparing fermented dry rice noodles. Through in vitro and in vivo experiments, the uric acid-lowering effect of this strain has been verified, which can alleviate hyperuricemia, regulate blood lipids, repair kidney and liver injuries caused by hyperuricemia, and can increase the content of volatile flavor compounds in fermented dry rice noodles. Thus, the technical solution of the present invention is formed to achieve the purpose of the present invention.

[0006] The technical solution of the present invention is as follows:

[0007] In the first aspect of the present invention, a Pediococcus acidilactici is provided. The Pediococcus acidilactici is Pediococcus acidilactici Mei.1103.1, the preservation unit is the China General Microbiological Culture Collection Center (abbreviated as CGMCC), the preservation number is CGMCC NO.32564, the preservation date is November 11, 2024, and the preservation address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0008] Furthermore, the degradation rate of inosine and guanosine by the Pediococcus acidilactici within 30 min is 100%, and the degradation rates of inosine and guanosine by the Pediococcus acidilactici are 6.67 mg / (L·min) and 6.67 mg / (L·min), respectively;

[0009] Furthermore, the Pediococcus acidilactici has the abilities of acid resistance, bile salt resistance, and gastrointestinal digestion resistance. Specifically, the survival rates of the Pediococcus acidilactici under the conditions of pH 2.0 and pH 3.0 are 81.28% and 100%, respectively; the survival rates of the Pediococcus acidilactici under the conditions of 0.15 wt% bile salt and 0.3 wt% bile salt are 93.77% and 90.55%, respectively; the survival rates of the Pediococcus acidilactici in artificial simulated gastric juice and artificial simulated intestinal juice are 87.13% and 79.08%, respectively.

[0010] Furthermore, the Pediococcus acidilactici has excellent antibacterial effects. Specifically, the Pediococcus acidilactici can inhibit several common pathogenic bacteria, including Staphylococcus aureus, Listeria, Escherichia coli, and Salmonella.

[0011] Furthermore, the biological characteristics of the Pediococcus acidilactici are Gram-positive. When cultured in MRS medium at 37 °C for 24 h, the colonies are white, round, with a moist surface, opaque, and regular edges; the cells are spherical.

[0012] The second aspect of the present invention provides a lactic acid bacteria agent, and the active ingredient of the lactic acid bacteria agent includes the Pediococcus acidilactici described above.

[0013] The third aspect of the present invention provides a freeze-dried lactic acid bacteria powder, and the active ingredient of the freeze-dried lactic acid bacteria powder includes the Pediococcus acidilactici described above.

[0014] Optionally, the freeze-dried lactic acid bacteria powder further includes a freeze-drying protectant, and the freeze-drying protectant includes the following components: skim milk powder, sodium L-ascorbate, sodium glutamate, xylo-oligosaccharide.

[0015] The fourth aspect of the present invention provides the application of the Pediococcus acidilactici described above, or the lactic acid bacteria agent described above, or the freeze-dried lactic acid bacteria powder described above in the preparation of a nucleoside degradation product or an immunomodulatory product.

[0016] Specifically, the degradation rate of inosine and guanosine by the Pediococcus acidilactici within 30 min is 100%; the immunomodulatory product has at least one of the following characteristics: 1) increasing the level of anti-inflammatory factor IL-10; 2) decreasing the levels of pro-inflammatory factors IL-6 and / or IL-1β and / or TNF-α.

[0017] The fifth aspect of the present invention provides the application of the Pediococcus acidilactici described above, or the lactic acid bacteria agent described above, or the freeze-dried lactic acid bacteria powder described above in the preparation of a product for reducing uric acid and preventing and / or treating hyperuricemia.

[0018] Specifically, the product has the ability to reduce serum uric acid levels.

[0019] The sixth aspect of the present invention provides the use of Pediococcus acidilactici or the lactic acid bacteria agent or the freeze-dried lactic acid bacteria powder thereof in the preparation of a product for preventing and / or treating kidney injury or a product for preventing and / or treating fatty liver.

[0020] Specifically, the product for preventing and / or treating kidney injury has the ability to reduce serum creatinine and / or blood urea nitrogen levels.

[0021] Specifically, the product for preventing and / or treating fatty liver can reduce serum triglyceride and / or low-density lipoprotein and / or high-density lipoprotein levels.

[0022] The seventh aspect of the present invention provides the use of the Pediococcus acidilactici or the lactic acid bacteria agent or the freeze-dried lactic acid bacteria powder thereof in the preparation of fermented dried rice noodles, and the use includes increasing the contents of volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dried rice noodles, increasing the lactic acid content in the fermentation broth, and reducing the pH of the fermentation broth.

[0023] The eighth aspect of the present invention provides a method for preparing fermented dried rice noodles, comprising the following steps:

[0024] S1. Soak the washed and air-dried late indica rice in water, and the amount of water added is 1.0 to 1.5 times the dry weight of the late indica rice. Inoculate the Pediococcus acidilactici or the lactic acid bacteria agent or the freeze-dried lactic acid bacteria powder thereof for fermentation; wherein, the inoculation amount of Pediococcus acidilactici is 10 5 CFU / g to 10 7 CFU / g, the fermentation temperature is 25 °C to 35 °C, the fermentation time is 7 days to 15 days, and the fermentation pH is 3 to 3.8;

[0025] S2. After the fermentation is completed, subject the fermented late indica rice to pulping, pressure filtration, massing, steaming, extrusion, boiling, cooling, powdering, and drying to obtain fermented dried rice noodles.

[0026] The ninth aspect of the present invention provides a fermented dried rice noodle obtained by using the above preparation method, and the contents of volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dried rice noodles are 1277.05 μg / kg and 313.47 μg / kg respectively.

[0027] The present invention has at least one of the following beneficial effects:

[0028] 1. A Pediococcus acidilactici Mei.1103.1 was isolated from the fermentation broth of Luocheng vermicelli. This strain can efficiently degrade inosine and guanosine, and also has excellent acid tolerance, bile salt tolerance and antibacterial properties. It does not have pathogenic genes, virulence genes and drug resistance genes, is sensitive to antibiotics, and does not have hemolytic activity. It is a safe probiotic that can be used in food. In addition, the Pediococcus acidilactici Mei.1103.1 can effectively reduce uric acid and relieve hyperuricemia; it has a protective effect on kidney damage, can reduce blood lipid and protect the liver, and has an anti-inflammatory and immunomodulatory effect.

[0029] 2. The present invention also applies Pediococcus acidilactici to the preparation of fermented dried rice noodles. The late indica rice fermented by the Pediococcus acidilactici Mei.1103.1 of the present invention can produce high concentrations of trans-2-decenal and 2-undecenal after being made into dried rice noodles. The Pediococcus acidilactici Mei.1103.1 provided by the present invention has strong acid-producing ability, can stabilize the rice noodle fermentation process, reduce the risk of contamination by miscellaneous bacteria, and ensure the stability of the flavor and quality of the fermented dried rice noodles.

[0030] The Pediococcus acidilactici of the present invention is Pediococcus acidilactici Mei.1103.1, which is deposited with the China General Microbiological Culture Collection Center (abbreviated as CGMCC), with the deposit number CGMCC NO.32564, the deposit date of November 11, 2024, and the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Growth curve of Pediococcus acidilactici Mei.1103.1 in Example 2 of the present invention ( Figure 1 A in Figure 1 ), Gram staining diagram ( Figure 1 B in

[0032] Figure 2 ), scanning electron microscopy diagram (

[0033] Figure 3 C in

[0034] Figure 4 Plasmid 1 circular diagram of Pediococcus acidilactici Mei.1103.1 in Example 5 of the present invention;

[0035] Figure 5It is the plasmid 2 circular map of Pediococcus acidilactici Mei.1103.1 in Example 5 of the present invention;

[0036] Figure 6 It is the hemolytic result in Example 5 of the present invention, Figure 6 where A in it is the positive control Staphylococcus aureus, Figure 6 and B in it is Pediococcus acidilactici Mei.1103.1;

[0037] Figure 7 It is the experimental result of Pediococcus acidilactici Mei.1103.1 reducing uric acid in zebrafish in Example 6 of the present invention;

[0038] Figure 8 It is the results of three items of rat renal function in Example 6 of the present invention, Figure 8 where A in it is the serum uric acid level, Figure 8 B in it is the serum creatinine level, Figure 8 and C in it is the serum urea nitrogen level;

[0039] Figure 9 It is the appearance of the rat kidney ( Figure 9 A in it) and the HE staining result diagram ( Figure 9 B in it) in Example 6 of the present invention;

[0040] Figure 10 It is the results of four items of rat blood lipids in Example 6 of the present invention, Figure 10 where A in it is the total cholesterol level, Figure 10 B in it is the triglyceride level, Figure 10 C in it is the high-density lipoprotein level, Figure 10 and D in it is the low-density lipoprotein level;

[0041] Figure 11 It is the appearance of the rat liver ( Figure 11 A in it) and the HE staining result diagram ( Figure 11 B in it) in Example 6 of the present invention;

[0042] Figure 12 It is the results of rat kidney inflammatory factors in Example 6 of the present invention, Figure 12 where A in it is IL-1β, Figure 12 B in it is IL-6, Figure 12 C in it is TNF-α, Figure 12 and D in it is IL-10.

[0043] Figure 13 It is the pH value change curve during the fermentation process in Example 8 of the present invention and Comparative Example 1.

[0044] Figure 14 It is the lactic acid content change curve during the fermentation process in Example 8 of the present invention and Comparative Example 1. Detailed implementation manners

[0045] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] In the embodiment of the present invention, the MRS liquid medium (Haibo Biotechnology Co., Ltd., Qingdao High-tech Industrial Park) is composed of the following components: glucose 20 g / L, peptone 10 g / L, beef extract powder 8.0 g, yeast extract powder 5 g, diammonium hydrogen citrate 2 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium acetate 5 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.04 g / L, Tween-80 1 g / L, and the pH is 5.7±0.2. The preparation method is as follows: Weigh 52.24 g of the culture medium sample, heat and dissolve it in 1 L of distilled water, and reserve it after autoclaving at 121 °C for 15 min.

[0047] In the embodiment of the present invention, the MRS solid medium (Haibo Biotechnology Co., Ltd., Qingdao High-tech Industrial Park) is composed of the following components: glucose 20 g / L, peptone 10 g / L, beef extract powder 8.0 g, yeast extract powder 5 g, diammonium hydrogen citrate 2 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium acetate 5 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.04 g / L, Tween-80 1 g / L, agar 15 g / L, and the pH is 5.7±0.2. The preparation method is as follows: Weigh 66.2 g of the culture medium sample, heat and dissolve it in 1 L of distilled water, dispense it, and reserve it after autoclaving at 121 °C for 20 min;

[0048] For those not specifying specific experimental steps or conditions in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. The raw materials or instruments used are all conventional products that can be obtained through commercial purchase, including but not limited to the raw materials or instruments used in the embodiments of the present application.

[0049] The following uses specific embodiments to further describe the present invention in detail, but the present invention is not limited to the following specific embodiments.

[0050] Example 1 Screening and identification of potential uric acid-lowering strains

[0051] 1. Isolation of strains

[0052] Pediococcus acidilactici Mei.1103.1 of the present invention was screened from the fermented liquid of Luocheng rice noodles in Jiangxi. The specific acquisition method is as follows: an appropriate amount of fermented liquid is put into a sterile nutrient broth for strain enrichment at 37 °C, and then inoculated into an MRS solid medium at a suitable concentration gradient. Strains with different colony morphologies, sizes, and colors are selected for streak plating, and this streak separation is repeated multiple times to obtain pure lactic acid bacteria cultures. A total of 20 lactic acid bacteria strains were isolated and named Mei.1103.1 - Mei.1103.20 respectively, and the isolated bacteria were stored in glycerol preservation tubes respectively.

[0053] 2. Screening of strains with nucleoside degradation ability

[0054] The above - isolated strains were respectively activated and cultured in an MRS liquid medium at 37 °C for 24 h. The activated fermentation broth was centrifuged at 5000 rpm for 10 min at 4 °C to obtain a precipitate, washed 3 times with phosphate - buffered saline, and then resuspended with a potassium dihydrogen phosphate solution containing purine nucleosides (0.2 g / L inosine and 0.2 g / L guanosine, with an addition amount of 4%). The mixture was incubated at 37 °C under anaerobic conditions for 30 min, and then a terminator perchloric acid was added at a ratio of 9:1 (v / v), and filtered through a 0.22 - μm filter. 20 μL of the filtrate was taken for high - performance liquid chromatography (HPLC, 1260 series, Agilent Technologies, CA, USA) analysis. The chromatographic conditions were as follows: Sunfire C18 column (5 μm, 250 mm × 4.6 mm; water); flow rate was 1 mL / min; column temperature was 25 °C; the wavelength of the ultraviolet detector was 254 nm; the mobile phase was methanol - phosphate (volume ratio 1:99). The degradation rate of nucleosides was calculated according to the following formula:

[0055]

[0056] where C 空白 is the nucleoside content in the supernatant of the reaction solution without adding lactic acid bacteria, and C 样品 are the nucleoside contents after adding lactic acid bacteria to the reaction respectively.

[0057] The nucleoside degradation effects of all lactic acid bacteria are not the same, ranging from 1.77% - 100%. Specifically, see Table 1. Among them, the screened Pediococcus acidilactici Mei.1103.1 has the best nucleoside degradation ability and can completely degrade inosine and guanosine within 30 min. After conversion, the degradation rates of Pediococcus acidilactici to inosine and guanosine are 6.67 mg / (L·min) and 6.67 mg / (L·min) respectively.

[0058] Table 1

[0059] Strain Inosine degradation rate (%) Guanosine degradation rate (%) Strain Inosine degradation rate (%) Guanosine degradation rate (%) Mei.1103.1 100.00± 0.00 100.00± 0.00 Mei.1103.11 11.08±5.21 45.19±5.33 Mei.1103.2 44.71±2.94 78.08±4.28 Mei.1103.12 22.01±3.99 10.12±4.67 Mei.1103.3 86.17±0.76 94.37±3.08 Mei.1103.13 95.50±2.54 73.93±9.94 Mei.1103.4 6.24±1.83 48.64±5.59 Mei.1103.14 29.07±9.01 73.37±2.83 Mei.1103.5 19.62±1.51 18.81±1.37 Mei.1103.15 69.49±1.93 64.44±4.05 Mei.1103.6 32.63±6.14 3.60±3.58 Mei.1103.16 38.19±0.84 58.85±5.98 Mei.1103.7 78.24±3.00 69.24±8.66 Mei.1103.17 77.28±0.95 41.77±8.21 Mei.1103.8 57.66±5.44 31.93±3.64 Mei.1103.18 37.55±4.14 85.52±5.23 Mei.1103.9 19.59±2.08 17.13±5.47 Mei.1103.19 50.16±1.61 42.58±8.32 Mei.1103.10 1.77±1.13 28.09±6.49 Mei.1103.20 79.78±3.07 95.23±2.91

[0060] 3. Strain Identification

[0061] The screened strain Mei.1103.1 was subjected to DNA extraction using a kit, followed by PCR amplification. Then, it was sent to Personal Biotechnology Co., Ltd. in Shanghai for 16S rRNA gene sequencing. The sequencing results were aligned with homologous sequences in NCBI using the BLAST tool to clarify the species relationship of the strain. This strain was identified as Pediococcus acidilactici. The Pediococcus acidilactici Mei.1103.1 was preserved. The preservation unit is the China General Microbiological Culture Collection Center (CGMCC), the preservation number is CGMCC NO. 32564, the preservation date is November 11, 2024, and the preservation address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0062] The 16S rRNA sequencing sequence of this bacterium is shown in SEQ ID NO: 1:

[0063]

[0064] Example 2 Observation on the Growth Characteristics and Cell Morphology of Pediococcus acidilactici Mei.1103.1

[0065] 1. Determination of the growth curve of Pediococcus acidilactici Mei.1103.1

[0066] Absorb 200 μL of the glycerol preservation solution of Pediococcus acidilactici screened in Example 1 and inoculate it into 50 mL of MRS liquid medium. Cultivate it at 37 °C and 160 r / min until the bacterial liquid becomes turbid, and perform the same operation for activation twice. Inoculate the activated Pediococcus acidilactici Mei.1103.1 into MRS liquid medium and cultivate it at 37 °C and 160 r / min for 30 h. Sampling is carried out at the culture times of 0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 28 h, and 30 h to measure the OD 600 value. The results are shown in Figure 1 A in. The Pediococcus acidilactici Mei.1103.1 of the present invention enters the logarithmic phase at about 8 h and enters the stationary phase at about 24 h.

[0067] 2. Gram staining of Pediococcus acidilactici Mei.1103.1

[0068] Use an inoculation loop to pick up a small amount of Pediococcus acidilactici and smear it evenly on a clean glass slide. Fix it by heating with a flame, drop oxalic acid ammonium crystal violet for staining for 1 min, wash it with tap water to remove the floating color, use iodine-potassium iodide solution for mordanting for 1 min, pour off the excess solution, decolorize it with 95% ethanol for 30 s, and then counterstain it with safranin dye for 30 s. Observe the morphology under an oil immersion lens with a magnification of 100 times under an electron microscope after decolorization. The specific morphology is as shown in Figure 1 B in. The obtained Pediococcus acidilactici Mei.1103.1 of the present invention is a Gram-positive bacterium.

[0069] 3. Scanning electron microscopy observation of Pediococcus acidilactici Mei.1103.1

[0070] Activate and culture Pediococcus acidilactici Mei.1103.1 with MRS liquid medium at 37 °C for 24 h. Centrifuge the activated fermentation broth at 5000 rpm for 10 min at 4 °C to obtain a precipitate, and wash it 3 times with phosphate buffer solution. Add 1 mL of 2.5% glutaraldehyde solution, mix well, fix it at 4 °C for 4 h, then centrifuge it at 5000 rpm for 10 min at 4 °C to obtain a precipitate. Dehydrate it with ethanol solutions with gradient volume concentrations (including five concentrations of 20%, 40%, 60%, 80%, and 100%), treat each concentration for 10 min, centrifuge at 5000 rpm for 3 min, and then observe the cell morphology with a scanning electron microscope. The results are as shown in Figure 1As shown by C in the figure, the Pediococcus acidilactici Mei.1103.1 obtained in the present invention is a spherical bacterium.

[0071] Example 3 Excellent stress resistance of Pediococcus acidilactici Mei.1103.1

[0072] The Pediococcus acidilactici Mei.1103.1 was activated and cultured in MRS liquid medium at 37 °C for 24 h, inoculated into MRS liquid medium with pH 2.0 and pH 3.0 and cultured for 3 h to evaluate its tolerance to acidic conditions, inoculated into MRS medium containing 0.15 wt% and 0.3 wt% bile salts and cultured for 3 h to evaluate its tolerance to bile salts, and inoculated into artificial simulated gastric juice and artificial simulated intestinal juice in vitro and cultured for 2 h to evaluate its tolerance to gastrointestinal environment.

[0073] Artificial simulated gastric juice: Prepare 40 mL of gastric electrolyte solution according to Table 2, adjust the pH to 3, then add pepsin and lipase, with the addition amounts of 2000 U / mL and 60 U / mL. After dissolving them evenly, sterilize with a microporous membrane and reserve for use.

[0074] Artificial simulated intestinal juice: Prepare 80 mL of intestinal electrolyte solution according to Table 2, adjust its pH to 7, then add pancreatin and bile salts, with the addition amounts of 100 U / mL and 0.3 mg / mL. After dissolving them evenly, sterilize with a microporous membrane and reserve for use.

[0075] Table 2

[0076] Component Artificial simulated gastric juice electrolyte Artificial simulated intestinal juice electrolyte KCl 0.69 g 1.36 g <![CDATA[KH2PO4]]> 0.09 g 0.16 g <![CDATA[NaHCO3]]> 1.25 g 8.5 g NaCl 1.18 g 1.92 g <![CDATA[MgCl2(H2O)6]]> 0.04 g 0.22 g <![CDATA[(NH4)2CO3]]> 0.05 g - <![CDATA[CaCl2(H2O)2]]> 0.10 g 0.08 g <![CDATA[H2O]]> 36.69 g 67.76 g

[0077] The calculation formula is as follows:

[0078] In the formula: CFUNt - the number of viable bacteria after treatment with acid / bile salt / artificial simulated gastric juice / artificial simulated intestinal juice, CFUN0 - the original number of viable bacteria;

[0079] The results are as Figure 2 shown. It can be seen from Figure 2 that the Pediococcus acidilactici obtained in the present invention has excellent acid tolerance, bile salt tolerance and gastrointestinal digestion tolerance.

[0080] Example 4 Excellent antibacterial property of Pediococcus acidilactici Mei.1103.1

[0081] Using the Oxford cup method, the inhibitory activity of the cell-free supernatant of Pediococcus acidilactici Mei.1103.1 against four common pathogenic bacteria (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, Salmonella) was determined. The Pediococcus acidilactici Mei.1103.1 obtained in the present invention has good antibacterial properties against the four common pathogenic bacteria, and the results are shown in Table 3 below.

[0082] Table 3

[0083]

[0084] Example 5 Safety Evaluation of Pediococcus acidilactici Mei.1103.1

[0085] The whole genome sequencing technology was used to determine and analyze the complete genome of Pediococcus acidilactici Mei.1103.1. The whole gene sequence was submitted to Genebank with the project number PRJNA1242910 and the biological sample number SAMN47610829. The results showed that the genome of Pediococcus acidilactici Mei.1103.1 consisted of 1 chromosome and 2 plasmids, with a total genome length of 2,142,273 bp. This genome contained 2084 coding genes, accounting for 85.55% of the genome sequence. These genes were closely related to the physiological functions, metabolic pathways and environmental adaptability of this strain. The average GC content of the genome was 40.01%, which conformed to the typical genomic characteristics of lactic acid bacteria, indicating that this strain had a relatively stable genomic structure. The genome assembly analysis showed that the genome of Pediococcus acidilactici Mei.1103.1 had good quality and high integrity. To further describe the structural characteristics of the genome of this strain, the detailed genome assembly statistics are shown in Table 4 below. The circular structure diagram of the genome ( Figures 3 - 5 ) intuitively demonstrated the distribution of each functional region in the genome.

[0086] Table 4

[0087]

[0088] 1. Analysis of Pathogenic / Virulence Genes of Pediococcus acidilactici Mei.1103.1

[0089] The Prokka and RAST tools were used to annotate the obtained sequencing data to identify potential pathogenic / virulence gene regions. The BLAST tool was used to align these genes with the known pathogenic gene database to screen for genes related to foodborne pathogens, pathogenicity or virulence, including but not limited to: enterotoxin genes (such as enterotoxin), collagenase genes (such as collagenase), invasive genes (such as invA), and cytotoxin genes (such as cytolysin). According to the relevant standards and index requirements in the "Technical Guidelines for the Safety Inspection and Evaluation of Strains Used as Health Food Ingredients (2020)", Pediococcus acidilactici Mei.1103.1 in the present invention was confirmed by genomic analysis not to contain common genes related to pathogenicity. These results indicated that the genome of this strain did not carry any known pathogenic genes and met the safety requirements for probiotics and food additives.

[0090] 2. Analysis of Antibiotic Resistance of Pediococcus acidilactici Mei.1103.1

[0091] The obtained sequencing data was subjected to genome annotation using Prokka and RAST tools to identify all possible genes and functional regions. The genomic data was aligned with known antibiotic resistance gene databases (such as CARD, ResFinder) using the BLAST tool, and genes related to antibiotic resistance were screened, including enzymes, membrane proteins, pumps, etc. encoded by resistance genes. In addition, antibiotic susceptibility was further confirmed through antibiotic susceptibility tests. Using the E-test method, the susceptibility of Pediococcus acidilactici Mei.1103.1 to common antibiotics was detected respectively, the minimum inhibitory concentration was recorded, and whether the strain had antibiotic resistance was determined. Through gene annotation and BLAST alignment analysis, no genes related to antibiotic resistance were found in the genome of Pediococcus acidilactici Mei.1103.1. Through the E-test of antibiotic susceptibility test, Pediococcus acidilactici Mei.1103.1 showed sensitivity to common antibiotics and did not show drug resistance. The analysis of this example shows that the genome of Pediococcus acidilactici Mei.1103.1 does not contain genes related to antibiotic resistance and does not show resistance to common antibiotics, meeting the safety requirements for probiotics and food additives.

[0092] 3. Hemolytic Analysis of Pediococcus acidilactici Mei.1103.1

[0093] Pediococcus acidilactici Mei.1103.1 was inoculated into MRS medium and cultured for 18 h until the bacterial solution entered the logarithmic growth phase. The cultured bacterial solution of Pediococcus acidilactici Mei.1103.1 was adjusted to an appropriate concentration (about 10 8 CFU / mL) by aseptic means. The bacterial solution was evenly streaked on the surface of a blood agar plate using a sterile inoculation loop. The blood agar plate was placed in an incubator at 37 °C for 24 - 48 h to observe whether the strain had hemolytic manifestations. The commercial Staphylococcus aureus ATCC 25923 (known as a β-hemolytic strain) was set as a positive control group. Hemolysis was judged by observing the hemolytic zone around the bacterial growth on the blood agar plate. According to the nature of the hemolytic zone, it could be divided into: β-hemolysis: The bacteria completely lysed red blood cells in the surrounding blood agar, showing a clear transparent area. α-hemolysis: The bacteria partially lysed red blood cells in the blood agar, forming a green or brown area. γ-hemolysis: The bacteria did not lyse red blood cells, and the blood agar remained unchanged. In this example, through the hemolytic test on the blood agar plate (the results are as Figure 6 shown, Figure 6 in which A is the positive control Staphylococcus aureus, Figure 6In this, B is Pediococcus acidilactici Mei.1103. 1) It was confirmed that Pediococcus acidilactici Mei.1103.1 does not have hemolytic activity under conventional culture conditions. This strain does not exhibit β-hemolysis or α-hemolysis characteristics, but rather presents as γ-hemolysis, that is, it has no ability to lyse red blood cells. Therefore, Pediococcus acidilactici Mei.1103.1 can be considered to not have hemolytic activity and meets the safety requirements for probiotics in foods and health products.

[0094] Example 6 Verification of the uric acid-lowering effect of Pediococcus acidilactici Mei.1103.1

[0095] 1. Animal experiments

[0096] The experimental animals for verifying the uric acid-lowering effect of Pediococcus acidilactici Mei.1103.1 in the present invention include zebrafish and rats.

[0097] Zebrafish were raised in fish-raising water at 28 °C (water quality: 200 mg of instant sea salt was added to every 1 L of reverse osmosis water, the conductivity was 450 - 550 μS / cm; pH was 6.5 - 8.5; hardness was 50 - 100 mg / L CaCO3). They were provided by the fish-raising center of Huante Co., Ltd. The experimental animal license number was: SYXK (Zhe) 2022 - 0004, and the feeding management met the requirements of international AAALAC certification (certification number: 001458). Randomly select 5 dpf wild-type AB strain zebrafish into 6-well plates, with 30 zebrafish in each well. They were divided into 6 groups, namely the control group, the model group, the low-dose group, the medium-dose group, the high-dose group, and the positive drug control group. The control group was given physiological saline, and the other groups were given potassium oxonate and sodium xanthine to induce hyperuricemia. In addition, the low-dose group was given 10 7 CFU of Pediococcus acidilactici Mei.1103.1, the medium-dose group was given 10 8 CFU of Pediococcus acidilactici Mei.1103.1, the high-dose group was given 10 9 CFU of Pediococcus acidilactici Mei.1103.1, and the positive control group was given 136 μg / mL allopurinol. After treatment at 28 °C for 1 day, data were collected using the Amplex® Red Uric Acid / Uricase Assay Kit and a multifunctional microplate reader software to analyze the uric acid fluorescence value of zebrafish, and the uric acid-lowering efficacy of Pediococcus acidilactici was evaluated based on the statistical analysis results of this index.

[0098] Twenty-four 6-week-old SPF-grade SD rats (weighing about 200 g) were purchased from Beijing Speifo Biotechnology Co., Ltd., with the license number SYXK (Gan) 2021-0001. The rats were housed in the animal experiment middle school, and the feeding environment was maintained stably: the relative humidity was maintained at 60%-80%, the temperature was maintained at 22-25 °C, the daily cyclic light and dark conditions were each 12 hours, and they had free access to food and water. The rats were weighed weekly and the body weights were recorded.

[0099] After one week of adaptive feeding of SD rats with ordinary standard feed and normal drinking water, the 24 rats were randomly divided into three groups, with 8 rats in each group. The specific grouping methods are as follows: (1) Control group (NC): fed with ordinary standard feed, and gavaged with 1 mL of 0.5% sodium carboxymethyl cellulose and 1 mL of normal saline every morning; (2) Model group (HUM): fed with high-fat and high-fructose feed, and gavaged with potassium oxonate-adenine to induce hyperuricemia (potassium oxonate 500 mg / kg, adenine 100 mg / kg) and 1 mL of normal saline every morning; (3) Pediococcus acidilactici group (Mei.1103.1): fed with high-fat and high-fructose feed, and gavaged with potassium oxonate-adenine to induce hyperuricemia (potassium oxonate 500 mg / kg, adenine 100 mg / kg) and Pediococcus acidilactici Mei.1103.1 (10 9 CFU / d).

[0100] 2. Evaluation of the uric acid-lowering effect of Pediococcus acidilactici Mei.1103.1

[0101] The experimental results of zebrafish ( Figure 7 ) showed that administration of Pediococcus acidilactici Mei.1103.1 could significantly reduce the uric acid level in zebrafish. Compared with the model group, the uric acid level decreased by about 16-41%. The uric acid level decreased more in the high-dose group than in the medium-dose and low-dose groups, suggesting that Pediococcus acidilactici Mei.1103.1 has an uric acid-lowering effect in zebrafish and shows a dose dependence. The experimental results in rats are as shown in Figure 8 A of Figure 8 A in

[0102] In A, the serum uric acid level in the model group increased significantly, indicating that a hyperuricemia model was successfully established. After the experimental group of rats was given Pediococcus acidilactici Mei.1103.1, the serum uric acid concentration decreased significantly, with a decrease of 52%. Combining the experimental results of zebrafish and rats, Pediococcus acidilactici Mei.1103.1 showed a significant uric acid-lowering effect, providing a scientific basis for further developing it as a potential health product or adjuvant therapeutic drug.

[0103] In addition to serum uric acid, the present experiment further measured and evaluated the renal function of rats (by measuring the levels of creatinine and blood urea nitrogen in serum as indicators of renal function). The kidneys of rats were fixed with 4% paraformaldehyde for 24 h, and then the samples were paraffin-embedded, sectioned, stained with HE, mounted, and finally the mounted sections were placed under a 100× microscope for microscopic examination and photography to observe and analyze the changes in the renal tissue structure of rats.

[0104] The results of the renal function indicators are as Figure 8 shown in B of Figure 8 and C of

[0105] The renal injury was further evaluated by analyzing the appearance and pathological sections of the kidneys. The results are as Figure 9 shown in A of Figure 9 and B of

[0106] 4. Lactobacillus pentosus Mei.1103.1 alleviates fatty liver

[0107] The present invention further measured and evaluated the liver function of rats in each group (by measuring the levels of four serum lipid items as indicators of liver function). At the same time, the livers of rats were fixed with 4% paraformaldehyde for 24 h, and then the samples were paraffin-embedded, sectioned, stained with HE, mounted, and finally the mounted sections were placed under a 100× microscope for microscopic examination and photography to observe and analyze the changes in the liver tissue structure of rats.

[0108] The changes in serum lipid levels are as Figure 10 shown, where Figure 10 A in Figure 10 is the total cholesterol level, Figure 10 B in Figure 10where D is the level of low-density lipoprotein. The model group showed significant increases in total cholesterol, triglycerides, and high-density lipoprotein, indicating abnormal blood lipid metabolism. The intervention of Pediococcus acidilactici Mei.1103.1 significantly reduced these abnormal blood lipid levels, suggesting that this strain may have a positive effect on fat accumulation by regulating lipid metabolism. The liver of the control group showed a normal reddish-brown color and a smooth surface, without obvious pathological changes. In contrast, the liver of the model group showed typical pathological features of fatty liver, mainly including a significant increase in liver volume and a yellowish color, indicating disordered liver fat metabolism and fat deposition. However, Pediococcus acidilactici Mei.1103.1 could effectively improve these manifestations of fatty liver, reduce liver fat deposition and volume increase. Further pathological section ( Figure 11 ) analysis showed that Figure 11 where A is the appearance of the rat liver in Figure 11 and B is the HE staining result map. The liver cells in the model group showed obvious pathological changes, including uneven cell size, blurred cell boundaries, and more fat vacuoles between cells. These changes indicate that the liver has suffered significant damage during the process of fat accumulation. After the intervention of Pediococcus acidilactici Mei.1103.1, these pathological changes were repaired to a certain extent, and the morphology of hepatocytes returned to near-normal, the cell size became uniform, the fat vacuoles decreased, and the cell boundaries became clearer, indicating that this strain has a certain liver protection effect and can improve the structural damage caused by fatty liver.

[0109] 5. Pediococcus acidilactici Mei.1103.1 alleviates inflammation

[0110] In the present invention, the inflammatory factors in the rat kidneys were further measured, and a commercial ELISA kit was used to quantitatively analyze the pro-inflammatory factors IL-6, IL-1β, TNF-α, and the anti-inflammatory factor IL-10. The results are as Figure 12 shown, Figure 12 where A is interleukin-1β (IL-1β) in Figure 12 and B is interleukin-6 (IL-6) in Figure 12 and C is tumor necrosis factor α (TNF-α) in Figure 12D in it is interleukin-10 (IL-10). The levels of pro-inflammatory factors IL-6, IL-1β and TNF-α in the model group were significantly increased, indicating that significant inflammatory reactions occurred in the kidney tissue. At the same time, the level of anti-inflammatory factor IL-10 decreased significantly, further demonstrating the imbalance of immune balance in the kidney and the exacerbation of the inflammatory state. Notably, after adding Pediococcus acidilactici Mei.1103.1, the expressions of pro-inflammatory factors IL-6, IL-1β and TNF-α in the kidney were significantly decreased, while the level of IL-10 increased, suggesting that this strain has a certain anti-inflammatory effect and can effectively alleviate the inflammatory reaction in the kidney. These results indicate that Pediococcus acidilactici Mei.1103.1 may alleviate the inflammatory damage of the kidney by regulating the immune response and balancing the expressions of pro-inflammatory and anti-inflammatory factors. By improving the function of the immune system, this strain may provide a new treatment idea for alleviating the inflammatory process of kidney diseases.

[0111] In summary, Pediococcus acidilactici Mei.1103.1 not only shows excellent effects in reducing serum uric acid levels, but also can significantly improve kidney function damage, liver damage caused by hyperuricemia, regulate blood lipids and alleviate inflammatory reactions. Therefore, as a natural probiotic, Pediococcus acidilactici Mei.1103.1 has broad clinical application prospects, especially in the treatment of hyperuricemia and related metabolic diseases (such as kidney damage, fatty liver, etc.), and has the potential to become a new natural health care ingredient. These research results further support the feasibility of its use as a clinical probiotic and lay a scientific foundation for its future application.

[0112] Example 7 Preparation of freeze-dried powder of uric acid-lowering Pediococcus acidilactici Mei.1103.1

[0113] Pediococcus acidilactici Mei.1103.1 that had been activated twice was inoculated into MRS liquid medium at an inoculation amount of 1% and cultured at 37 °C for 24 h. After that, the cell precipitate was collected by centrifugation at 4500 rpm for 10 min, washed 3 times with sterile physiological saline or phosphate buffer, and the cell precipitate was mixed evenly with the freeze-drying protectant according to 1:1 (by mass). Then it was placed in a -80 °C refrigerator for pre-freezing for 12 h, and then transferred to a vacuum freeze-dryer for freeze-drying for 48 h to prepare the freeze-dried powder. The preparation method of the freeze-drying protectant is as follows: 15 g of skim milk powder, 3 g of sodium L-ascorbate, 3 g of sodium glutamate, and 5 g of xylo-oligosaccharide are dissolved in 100 mL of 0.9% physiological saline, and then heated in a water bath at 65 °C for 30 min for disinfection and sterilization.

[0114] Example 8 Preparation of fermented dried rice noodles

[0115] (1) Rice fermentation: Soak the washed and air-dried late indica rice in water, with the water soaking amount being 1.35 times the dry weight of the late indica rice. Inoculate Pediococcus acidilactici Mei.1103.1 - Mei.1103.5 screened in Example 1, and the inoculation amount is 10 6 CFU / g. Control the fermentation temperature at 30 °C and ferment sealed for 11 days.

[0116] (2) Processing of fermented dry rice noodles: After the late indica rice is fermented well, it is further processed into fermented dry rice noodles through grinding into slurry, pressure filtration, dough making, steaming the dough, extruding the noodles, boiling the noodles, cooling, arranging the noodles in a tray, and drying. The specific method is as follows:

[0117] Grinding into slurry: After the indica rice fermentation is completed, grind it into rice slurry by wet grinding method;

[0118] Pressure filtration: Press and filter the wet-ground rice slurry with a plate and frame filter press to form a rice flour block, and control the moisture content of the rice flour block at 45%;

[0119] Dough making: Extrude the pressure-filtered rice flour block with a dough-making machine into a cylindrical dough with a bottom diameter of 14 cm and a height of 25 cm;

[0120] Steaming the dough: Steam the made cylindrical dough with 105 °C steam for 80 min;

[0121] Extruding the noodles: Extrude the steamed dough into noodles with a diameter of 2.0 mm by pressurization;

[0122] Boiling the noodles: Heat the extruded noodles in boiling water for 6 min;

[0123] Cooling: Take out the boiled noodles and cool them in cold water;

[0124] Arranging the noodles in a tray: Place the cooled noodles in a mold with a length, width, and height of 25 cm × 15 cm × 5 cm and arrange them in a row-like shape;

[0125] Drying: Place the cooled noodles in a lamp drying device for drying.

[0126] Comparative Example 1: Preparation of naturally fermented dry rice noodles

[0127] (1) Rice fermentation: Soak the washed and air-dried late indica rice in water, with the water soaking amount being 1.35 times the dry weight of the late indica rice. Control the fermentation temperature at 30 °C and ferment sealed for 11 days.

[0128] (2) Processing of fermented dry rice noodles: After the rice is fermented well, it is further processed into fermented dry rice noodles through grinding into slurry, pressure filtration, dough making, steaming the dough, extruding the noodles, boiling the noodles, cooling, arranging the noodles in a tray, and drying. The specific steps are the same as in Example 8.

[0129] The contents of volatile flavor substances in the fermented dried rice noodles prepared in Example 8 and Comparative Example 1, as well as the pH and lactic acid content in the fermentation broth during the fermentation process, were detected as follows:

[0130] (1)Detection of volatile flavor substance content: It was carried out by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The chromatographic column was DB-Wax (30 m×0.25 mm×0.25 μm, Agilent), and methyl myristate was used as the internal standard for relative quantification. The results of the volatile flavor substance content in the fermented dried rice noodles prepared in Example 8 and Comparative Example 1 are shown in Table 5.

[0131] Table 5

[0132]

[0133] It can be seen from the results in Table 5 that the content of enal flavor substances in Comparative Example 1 was the lowest. The contents of trans-2-decenal and 2-undecenal were only 184.68 μg / kg and 40.50 μg / kg respectively, indicating that the content of enal flavor substances in naturally fermented rice noodles was extremely low. Among the rice noodles fermented with Pediococcus acidilactici inoculation, compared with the inoculation of Mei.1103.2 - Mei.1103.5, the content of enal volatile flavor substances in the fermented dried rice noodles inoculated with Mei.1103.1 was the highest. The contents of trans-2-decenal and 2-undecenal were 1277.05 μg / kg and 313.47 μg / kg respectively, indicating that inoculation with Mei.1103.1 was helpful to increase the contents of trans-2-decenal and 2-undecenal in the fermented dried rice noodles. As important flavor-active compounds, trans-2-decenal and 2-undecenal can significantly enhance the flavor quality of the fermented dried rice noodles, and the products fermented by the Mei.1103.1 strain showed the most prominent flavor characteristics.

[0134] (2)Detection of pH and lactic acid during the fermentation process

[0135] The changes in pH and lactic acid during the rice fermentation process in Example 8 and Comparative Example 1 were detected, and the results are as Figure 13 、 Figure 14 shown. From Figure 13 、 Figure 14It can be seen that the pH value of Comparative Example 1 is the highest and the lactic acid content is the lowest. At the end of fermentation, the pH value and lactic acid content in Comparative Example 1 are 4.71 and 34.12 mmol / L respectively, indicating that the acid production ability of Comparative Example 1 is weak. Among the rice noodles fermented with Pediococcus acidilactici, compared with the inoculation of Mei.1103.2 - Mei.1103.5, the pH value of the fermented dried rice noodles inoculated with Mei.1103.1 decreased the fastest and the lactic acid content increased the fastest. At the end of fermentation, the pH value and lactic acid content were 3.42 and 78.69 mmol / L respectively, indicating that Mei.1103.1 has the strongest acid production ability and can better inhibit the growth of other miscellaneous bacteria.

[0136] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes, should be covered within the protection scope of the present invention.

Claims

1. A Pediococcus acidilactici, characterized in that, The Pediococcus acidilactici is Pediococcus acidilactici Mei.1103.1, which is preserved in the China General Microbiological Culture Collection Center. The preservation number is CGMCC NO.32564, the preservation date is November 11, 2024, and the preservation address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

2. The Pediococcus acidilactici according to claim 1, wherein the degradation rates of the Pediococcus acidilactici to inosine and guanosine are 6.67 mg / (L·min) and 6.67 mg / (L·min) respectively.

3. A lactic acid bacteria agent, characterized in that, The active ingredient of the lactic acid bacteria agent includes the Pediococcus acidilactici according to any one of claims 1 to 2.

4. A lyophilized powder of lactic acid bacteria, characterized in that, The active ingredient of the freeze-dried lactic acid bacteria powder includes the Pediococcus acidilactici according to any one of claims 1 to 2.

5. Use of the Pediococcus acidilactici according to any one of claims 1 to 2, or the lactic acid bacteria agent according to claim 3, or the freeze-dried lactic acid bacteria powder according to claim 4 in the preparation of a nucleoside degradation product or an immune regulation product.

6. Use of the Pediococcus acidilactici according to any one of claims 1 to 2, or the lactic acid bacteria agent according to claim 3, or the freeze-dried lactic acid bacteria powder according to claim 4 in the preparation of a product for reducing uric acid, preventing and / or treating hyperuricemia.

7. Use of the Pediococcus acidilactici according to any one of claims 1 to 2, or the lactic acid bacteria agent according to claim 3, or the freeze-dried lactic acid bacteria powder according to claim 4 in the preparation of a product for preventing and / or treating kidney injury or a product for preventing and / or treating fatty liver.

8. Use of Pediococcus acidilactici according to any one of claims 1 to 2, or the lactic acid bacteria agent according to claim 3, or the freeze-dried lactic acid bacteria powder according to claim 4 in the preparation of fermented dried rice noodles, characterized in that, The use includes increasing the contents of the volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dried rice noodles, increasing the lactic acid content in the fermentation broth and reducing the pH of the fermentation broth.

9. A method for preparing fermented dried rice noodles, characterized in that, Comprising the following steps: S1. Soak the washed and dried late indica rice in water, with the water addition amount being 1.0 to 1.5 times the dry weight of the late indica rice, and inoculate it with the Pediococcus acidilactici described in any one of claims 1 to 2, or the lactic acid bacteria agent described in claim 3, or the freeze-dried lactic acid bacteria described in claim 4 for fermentation; among them, the inoculation amount of Pediococcus acidilactici is 10 5 CFU / g to 10 7 CFU / g, the fermentation temperature is 25 °C to 35 °C, and the fermentation time is 7 days to 15 days; S2. After the fermentation is completed, the fermented late indica rice is subjected to pulping, pressure filtration, massing, steaming, extrusion, boiling, cooling, pan powdering, and drying to obtain fermented dried rice noodles.

10. A fermented dried rice noodle obtained by the preparation method according to claim 9, wherein the contents of the volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dried rice noodles are 1277.05 μg / kg and 313.47 μg / kg respectively.

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