Lactobacillus plantarum WYL8 with lipid oxidation resistance function and its application

Abstract

The present invention discloses a Lactobacillus plantarum WYL8 with anti-lipid oxidation function and its application, belonging to the field of microbial technology, and provides a Lactobacillus plantarum ( Lactiplantibacillus plantarum ) WYL8. The Lactobacillus plantarum WYL8 was deposited at the China Center for Type Culture Collection on June 21, 2024. The deposit address is Wuhan University, Wuhan, China, and the deposit number is CCTCC NO: M 20241344. And the application of Lactobacillus plantarum WYL8 in the storage of wheat germ. Applying Lactobacillus plantarum WYL8 to the storage of wheat germ inhibits the oxidative rancidity of fat, ensures the quality of wheat germ, and prevents the loss of nutritional value and economic value.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and particularly relates to a Lactobacillus plantarum WYL8 with anti-lipid oxidation function and its application. Background Art

[0002] Wheat germ is a by-product of wheat flour processing, rich in fat and protein, and is a high-quality food and feed raw material. However, lipase (LA) and lipoxygenase (LOX) in wheat germ are activated during the flour-making process, resulting in rapid oxidation and rancidity of fat, generating off-flavors, deteriorating the quality of wheat germ, and significantly reducing its nutritional and economic value. Affected by LA and LOX, fresh wheat germ has a very short storage period and is difficult to store and transport over long distances for a long time. Currently, mainly through heat drying to inactivate LA and LOX, or adding chemical reagents to inactivate the enzymes, thereby achieving the stabilization of wheat germ. Existing treatment methods have problems such as high energy consumption, high cost, serious nutrient loss, and chemical residues, increasing the consumption cost of wheat germ and restricting its application scenarios.

[0003] It is imperative to study new storage methods for wheat germ with the advantages of environmental friendliness, low cost, and easy operation. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a Lactobacillus plantarum WYL8 with anti-lipid oxidation function and its application. Applying Lactobacillus plantarum WYL8 to the storage of wheat germ inhibits the oxidation and rancidity of fat, ensuring the quality of wheat germ and preventing the loss of its nutritional and economic value.

[0005] To achieve the above object, the present invention provides a Lactobacillus plantarum Lactiplantibacillus plantarum WYL8 with anti-lipid oxidation function. The Lactobacillus plantarum WYL8 was deposited at the China Center for Type Culture Collection on June 21, 2024. The deposit address is Wuhan University, Wuhan, China, and the deposit number is CCTCC NO: M20241344.

[0006] The present invention also provides the application of the Lactobacillus plantarum WYL8 in the storage of wheat germ.

[0007] The present invention also provides the application of the Lactobacillus plantarum WYL8 in the preparation of anti-lipid oxidation preparations.

[0008] The present invention also provides an anti-lipid oxidation preparation, comprising the Lactobacillus plantarum WYL8.

[0009] The present invention also provides a method for storing wheat germ using the Lactobacillus plantarum WYL8, comprising the following steps: inoculating the Lactobacillus plantarum WYL8 into wheat germ and fermenting it sealed for 24 h.

[0010] Preferably, the viable count of the Lactobacillus plantarum WYL8 is 1.2×10 7 CFU / mL, and the inoculation amount of the Lactobacillus plantarum WYL8 is 4% by volume fraction.

[0011] Preferably, the sealed fermentation is carried out under light-proof conditions, and the temperature of the sealed fermentation is 37°C.

[0012] Compared with the prior art, the present invention has the following advantages and technical effects:

[0013] The present invention uses lipid-rich fermented foods as raw materials to isolate epiphytic bacteria. Taking antioxidant capacity, malondialdehyde content, and lipase activity as screening indicators, antioxidant bacteria suitable for wheat germ are selected, and the physiological characteristics, safety, and anti-lipid oxidation effect of wheat germ of the strains are analyzed and evaluated. The Lactobacillus plantarum WYL8 is obtained and applied to the storage of wheat germ, inhibiting the oxidative rancidity of fat, ensuring the quality of wheat germ, and not losing its nutritional value and economic value. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0015] Figure 1 It is the determination result of the antioxidant performance of Lactobacillus plantarum WYL8 in MRS broth. Among them, A is Lactobacillus plantarum WYL8 grown on the LBS plate, B is the growth curve of Lactobacillus plantarum WYL8, C is the LPS enzyme activity, D is the total antioxidant capacity (T-AOC), E is the inhibition rate of hydroxyl radicals (OH· - ) inhibition rate, F is the inhibition rate of 1,1-diphenyl-2-picrylhydrazyl (DPPH·), MRS represents fresh MRS broth containing 0.1 g / 100 mL LPS, WYL8 represents MRS broth after inoculating Lactobacillus plantarum WYL8 for fermentation, and different lowercase letters indicate significant differences ( P <0.05);

[0016] Figure 2 It is the morphological and identification results of Lactobacillus plantarum WYL8. Among them, A is the Gram staining map; B is the 16S rDNA PCR electrophoresis map, C is the culture map on the casein medium, D is the phylogenetic tree map;

[0017] Figure 3 It is the antibacterial effect and hemolytic test results of Lactobacillus plantarum WYL8. Among them, A is Lactobacillus plantarum WYL8 and Escherichia coli (E.coli )Effect, B is the effect of Lactobacillus plantarum WYL8 and Staphylococcus aureus ( S.aureus )Effect, C is the effect of Lactobacillus plantarum WYL8 and Salmonella ( S.enteritidis )Effect, D is coated on the blood agar plate S.aureus , E is Lactobacillus plantarum WYL8 coated on the blood agar plate, F is the statistical chart of the inhibition zone diameter of Lactobacillus plantarum WYL8 against indicator bacteria, and different lowercase letters indicate significant differences ( P < 0.05);

[0018] Figure 4 shows the effect of Lactobacillus plantarum WYL8 treatment on the appearance of wheat germ. Among them, A is the original sample group (WG), fresh wheat germ (water content 20%), B is the blank control group (CON), fresh wheat germ (water content 20%) is left standing for 24 h, C is the natural fermentation group (CK), fresh wheat germ (water content 70%) is naturally fermented for 24 h, and D is the Lactobacillus plantarum WYL8 fermentation group (WYL8), fresh wheat germ inoculated with Lactobacillus plantarum WYL8 (water content 70%) is fermented for 24 h;

[0019] Figure 5 shows the effect of Lactobacillus plantarum WYL8 treatment on the anti-lipid oxidation index of wheat germ. Among them, A is the original sample group (WG), fresh wheat germ (water content 20%), B is the blank control group (CON), fresh wheat germ (water content 20%) is left standing for 24 h, C is the natural fermentation group (CK), fresh wheat germ (water content 70%) is naturally fermented for 24 h, and D is the Lactobacillus plantarum WYL8 fermentation group (WYL8), fresh wheat germ inoculated with WYL8 (water content 70%) is fermented for 24 h, and different lowercase letters indicate significant differences ( P < 0.05);

[0020] Figure 6 shows the fermentation stability of wheat germ after 8 h of oxygen exposure under different treatments. WG represents the original sample group, fresh wheat germ (water content 20%), CON represents the blank control group, fresh wheat germ (water content 20%) is aerobically exposed after standing for 16 h, CK represents the natural fermentation group, fresh wheat germ (water content 70%) is aerobically exposed after natural fermentation for 16 h, and WYL8 represents the Lactobacillus plantarum WYL8 fermentation group, fresh wheat germ inoculated with WYL8 (water content 70%) is aerobically exposed after fermentation for 16 h;

[0021] Figure 7Statistical chart of the fermentation stability of wheat germ after different treatments with 8 h of oxygen exposure. Among them, A is the original sample group (WG), fresh wheat germ (with a water content of 20%) is exposed to oxygen for 8 h, B is the blank control group (CON), fresh wheat germ (with a water content of 20%) is left standing for 16 h and then exposed to oxygen for 8 h, C is the natural fermentation group (CK), fresh wheat germ (with a water content of 70%) is naturally fermented for 16 h and then exposed to oxygen for 8 h, D is the Lactobacillus plantarum WYL8 fermentation group (WYL8), fresh wheat germ is inoculated with WYL8 (with a water content of 70%) and fermented for 16 h and then exposed to oxygen for 8 h. Different lowercase letters indicate significant differences ( P <0.05). Detailed implementation manners

[0022] The various exemplary implementation manners of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0023] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0024] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0025] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0026] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, that is, they are meant to include but not be limited to.

[0027] Example 1

[0028] 1 Materials and methods

[0029] 1.1 Samples and Treatments

[0030] Use fatty fermented foods including preserved bacon, preserved duck, preserved chicken, preserved fish and Chinese sausage as the original samples. Use a sterile swab to fully wipe the epidermis of the fatty samples, and then transfer the swab head to a 15 mL sterile centrifuge tube, add 10 mL of MRS broth, and culture at 37 °C for 24 h to prepare a microbial enrichment solution. Use fresh wheat germ (with a water content of 20%, provided by Shijiazhuang Agricultural Standard Biotechnology Co., Ltd.) as the fermentation raw material, and store it sealed at -20 °C for later use.

[0031] 1.2 Screening of Strains

[0032] 1.2.1 Primary Screening

[0033] (1) Screening and purification of lactic acid bacteria: Using the streak plate method, inoculate the microbial enrichment solution in 1.1 onto LBS solid medium (lactobacillus selective medium, Qingdao Haibo Biotechnology Co., Ltd.), and culture anaerobically at 37 °C for 48 h. After the colonies grow, select single colonies with different morphologies for purification. Inoculate the purified strains into MRS liquid medium, culture at 37 °C for 24 h, adjust the OD of the fermentation broth 600 to 0.75 ± 0.05 to prepare the seed solution of the test strains, and store it temporarily at 4 °C for later use.

[0034] (2) Screening of antioxidant lactic acid bacteria: Inoculate the seed solution of the test strains into MRS liquid medium at an inoculation amount of 2%, culture statically at 37 °C for 24 h, centrifuge at 4 °C and 6000 rpm for 10 min, and take the supernatant. According to the instructions, use a kit (Nanjing Jiancheng) to detect the total antioxidant capacity (T-AOC), 1,1-diphenyl-2-picrylhydrazyl (DPPH·) and hydroxyl radical (OH· - ) inhibition rates of the supernatant, and respectively select the 5 microorganisms with the highest T-AOC and the strongest DPPH· and OH· - inhibition rates for rescreening.

[0035] 1.2.2 Rescreening

[0036] Prepare MRS liquid medium with a LPS (lipase, enzyme activity > 100 U / mg, Beijing Coolaber Technology Co., Ltd.) concentration of 0.1 g / 100 mL, sterilize it through a sterile filter membrane (0.45 μm), dispense it into 15 mL sterile centrifuge tubes, inoculate the seed solution of each strain obtained from the above primary screening at an inoculation amount of 2%, after culturing statically at 37 °C for 24 h, centrifuge the fermentation broth at 4 °C and 6000 rpm, and take the supernatant. According to the instructions, use a kit (Gries) to detect the LPS activity, and use the pre-fermentation as a control, and retain the 3 microorganisms with the strongest inhibitory effect on LPS activity for final screening.

[0037] 1.2.3 Final Screening

[0038] Prepare an aqueous solution with a LPS concentration of 0.1 g / 100 mL and a LOX (lipoxygenase, enzyme activity > 50000 U / mg, Shanghai Yuanye Bio-Technology Co., Ltd.) concentration of 1 mg / 100 mL, and inoculate 4% of the seed bacterial solution obtained from the second screening (1×10 8 CFU / mL) to prepare the starter. Thaw fresh wheat germ at 0 °C, and mix the wheat germ and the starter thoroughly at a ratio of 1 g∶3 mL. Ferment at 37 °C for 24 h, and use an equal amount of sterile water treatment as the control. Homogenize the fermentation substrate in an ice bath, centrifuge at 4 °C and 6000 rpm for 10 min, and take the supernatant. According to the instructions, use a kit (Grees, Nanjing Jiancheng) to detect the LPS enzyme activity and MDA content in the supernatant, and calculate the inhibition rate of the target strain fermentation on LPS and the reduction rate of MDA. Select the strain with the best effect for subsequent research.

[0039] 1.3 Identification of strains

[0040] Observe the size, morphology, color and other indicators of the colonies, pick single colonies for Gram staining, further observe the bacterial cells under a 100-fold oil immersion microscope, use biochemical identification tubes (Hangzhou Microbial Reagent Co., Ltd.) to conduct physiological and biochemical identification of the strains, and use Durham tubes for gas production experiments; use Ezup Column Bacterial Genomic DNA Extraction Kit (Sangon Biotech (Shanghai) Co., Ltd.) to extract DNA from the test strains. Use primer pairs to perform PCR amplification on the bacterial genome. The purified PCR products are sent to Sangon Biotech (Shanghai) Co., Ltd. for DNA sequencing, and the sequencing results are compared with the NCBI 16S database, and a phylogenetic tree is constructed using MEGA7.0 software.

[0041] 1.4 Analysis of strain characteristics

[0042] 1.4.1 Growth performance

[0043] Inoculate the WYL8 seed bacterial solution at 2% into MRS broth, immediately take samples after thorough mixing and measure the absorbance at a wavelength of 600 nm, then place it statically at 37 °C and continuously culture for 24 h. Take samples every 2 h to measure the absorbance and pH. Each group conducts three parallel experiments. With time as the abscissa and OD 600 , pH value as the ordinate, draw the growth curve and acid production curve of the strain.

[0044] 1.4.2 Antibacterial characteristics

[0045] Using Escherichia coli K88 ( Escherichia coli, E.coli ), Salmonella ATCC14028 ( Salmonella enteritidis, S.enteritidis ), and Staphylococcus aureus ATCC25923 ( Staphylococcus aureus,S.aureus ), which are the pathogen indicator bacteria (all kindly provided by the College of Animal Medicine, Hunan Agricultural University). The antibacterial properties of WYL8 against the indicator bacteria were detected by the punching method. Take the bacterial liquid in the stationary phase of the indicator bacteria and adjust the concentration to 1×10 8 CFU / mL, coat it on the LB plate with a sterile swab, punch holes with a sterile puncher (φ = 8 mm) after the bacterial liquid is absorbed, then inoculate 50 μL of the test bacterial liquid into the holes, and measure the diameter of the antibacterial circle after static culture at 37°C for 24 h.

[0046] 1.4.3 Safety detection

[0047] The antibiotic sensitivity of WYL8 was detected by the disk diffusion method. Use a sterile swab to coat the bacterial liquid in the stationary phase (1×10 8 CFU / mL) on the MRS plate. After the bacterial liquid is absorbed, use sterile forceps to place the drug sensitivity disk (φ = 6 mm) on the surface of the culture medium, gently press the drug sensitivity disk to make it stick firmly, and measure the diameter of the antibacterial circle of the drug sensitivity disk after culturing at 37°C for 24 h. Inoculate WYL8 onto the blood plate by the streaking method and culture it at 37°C for 24 h to observe whether there is a hemolysis circle, and use the inoculated S.aureus blood plate as a control.

[0048] 1.5 Wheat germ fermentation test

[0049] Using the strain WYL8 as the fermentation inoculant, inoculate it into fresh wheat germ (containing 20% moisture) at 1.2×10 7 CFU / mL, the inoculation amount is 4% by volume fraction, adjust the final humidity of the fermentation system to 70% with sterile water, mix well and ferment at 37°C in a sealed and light-proof manner for 24 h, which is recorded as the WYL8 fermentation group (WYL8), and use fresh wheat culture without inoculating the fermentation inoculant with the same humidity as the control (CK) and carry out fermentation treatment under the same conditions; use fresh wheat germ (humidity of 20%) as the initial group (WG), and store it at -20°C in a sealed manner; repeat the preparation of the initial group samples, ferment at 37°C in a sealed and light-proof manner for 24 h, which is recorded as the natural fermentation group (CON). After 24 h, place the samples in an environment of 0°C to terminate fermentation, and thaw the initial samples at 0°C. After the samples of each group are restored to room temperature (26°C), supplement the water content of the WG group and the CON group to 70% with sterile water, then measure the pH value of the samples of each group respectively, prepare the supernatant according to the operation in 1.2.3, and detect the LPS, T-AOC, and MDA levels of the samples of each group using a kit (Grees, Nanjing Jiancheng) according to the instructions.

[0050] 1.6 Oxygen exposure test of fermented wheat germ

[0051] Expose fermented or fresh wheat germ to an aerobic environment, and evaluate the effect of strain WYL8 treatment on the aerobic stability of wheat germ by detecting the levels of pH, LPS, T-AOC, and MDA. The specific operation is as follows: Set up the WYL8 fermentation group (WYL8), control group (CK), initial group (WG), and natural fermentation group (CON) according to the operation in 1.5. Among them, the WYL8, CK, and CON groups are all fermented at 37°C under sealed and light-proof conditions. After 16 hours, the samples are placed in an environment of 0°C to terminate fermentation. The samples in the WG group are thawed at 0°C. After each group of samples is restored to room temperature (32°C), equal amounts of samples are taken and placed in sterile petri dishes of the same size and flattened. Place them in a natural environment at 32°C and observe once every 2 hours for 8 consecutive hours. Record the changes in each group of wheat germ, and supplement the water content of each group to 70% with sterile water at 8 hours. Then, measure the pH value of each group of samples, prepare the supernatant according to the operation in 1.2.3, and detect the levels of LPS, T-AOC, and MDA in each group of samples using a kit (Nanjing Jiancheng) according to the instructions.

[0052] 1.7 Data Statistics and Analysis

[0053] Three parallel tests were set up, and the results are expressed as "mean ± standard deviation". The data were analyzed by t-test or one-way ANOVA using GraphPad Prism 9.5.0 analysis software, and the significance level was P <0.05.

[0054] 2 Results and Analysis

[0055] 2.1 Screening of Lipid Oxidation-Resistant Lactic Acid Bacteria

[0056] 2.1.1 Antioxidant Performance of Strain WYL8 in MRS Broth

[0057] After primary screening and rescreening, a strain of Lactobacillus plantarum WYL8 with lipid antioxidant properties was finally screened from lipid-rich samples (as shown in Figure 1 A). The OD of the MRS broth inoculated with WYL8 did not change significantly within 2 hours, and strain WYL8 was in the lag phase; it grew rapidly from 2 to 12 hours, showing logarithmic growth and being in the logarithmic phase; after 12 hours, the growth slowed down and tended to be stable, and the strain entered the stationary phase (as shown in 600 B). The pH of the fermentation broth decreased rapidly within 10 hours, gradually tended to be stable over time, and maintained at pH = 3.8 (as shown in Figure 1 B). Compared with before fermentation, the LPS enzyme activity could be significantly reduced after fermentation with WYL8 ( Figure 1 <0.05) (as shown in P C). In addition, WYL8 could significantly improve the total antioxidant capacity of the fermentation substrate and the inhibition rates against OH· Figure 1 and DPPH· ( - and DPPH· inhibition rates (P <0.05) (such as Figure 1 in D, Figure 1 in E and Figure 1 in F).

[0058] 2.1.2 Effects of Strain WYL8 on LPS and MDA Levels in Wheat Germ

[0059] Table 1 Effects of Strain WYL8 on LPS and MDA Levels in Wheat Germ Medium

[0060]

[0061] Note: In the WYL8 group, wheat germ was inoculated with WYL8 and fermented for 24 h; in the CON group, wheat germ was statically placed for 24 h under the same conditions. Different lowercase letters indicate significant differences (< P 0.05).

[0062] As shown in Table 1, compared with the control group, after the wheat germ containing high - activity LPS and LOX was treated with strain WYL8, the LPS enzyme activity decreased significantly from 190.12 U / mL to 21.96 U / mL, and the MDA content decreased significantly (< P 0.05). The inhibition rate of WYL8 treatment on LSP could reach 88.43%, reducing the production of MDA by more than 50%.

[0063] 2.2 Identification of Strain WYL8

[0064] After strain WYL8 was cultured on an LBS plate for 24 h, it showed a circular colony with a diameter of 3 ± 0.18 mm, milky white, convex in the middle, smooth surface, neat edge, and an obvious calcium - dissolving zone around the colony (such as Figure 1 in A), did not secrete caseinase, and could secrete a large amount of organic acids on the casein medium to denature and precipitate proteins (such as Figure 2 in C). The Gram - staining result showed that it was Gram - positive, short - rod - shaped (such as Figure 2 in A). After gene sequencing, based on the 16S rRNA sequence, a phylogenetic tree of strain WYL8 was constructed. Strain WYL8 and Lactobacillus plantarum 2640 (MT611661.1) converged on one branch (such as Figure 2 in B and Figure 2 in D). This strain had no catalase reaction and did not produce gas. Except for sorbitol and sodium hippurate, it could utilize 9 carbon sources such as raffinose, cellobiose, maltose, lactose, and inulin (as shown in Table 2). Based on the above identification results, strain WYL8 was finally determined to be Lactobacillus plantarum ( Lactiplantibacillus plantarum ), named Lactobacillus plantarum WYL8 ( Lactiplantibacillus plantarumWYL8) was deposited in the China Center for Type Culture Collection with the deposit number CCTCC NO: M 20241344.

[0065] Table 2 Physiological and biochemical identification results of strain WYL8

[0066]

[0067] Note: "+" indicates positive; "-" indicates negative.

[0068] 2.3 Antibacterial activity and safety of strain WYL8

[0069] Using E.coli K88, S.enteritidis ATCC14028 and S.aureus ATCC25923 to conduct antibacterial tests on the antibacterial activity of strain WYL8, the results showed that WYL8 had varying degrees of inhibitory effects on 3 common pathogenic bacteria (such as Figure 3 A in Figure 3 B in Figure 3 C in E.coli 】> S.aureus 】> S.enteritidis , (such as Figure 3 F in S.aureus In addition, compared with Figure 3 D in Figure 3 E in

[0070] Table 3 Results of drug sensitivity test

[0071]

[0072] As shown in Table 3, it is the results of the drug sensitivity test of strain WYL8.

[0073] 2.4 Effects of different treatments on anti-lipid oxidation of wheat germ

[0074] The anti-lipid antioxidant effects of different treatment methods on fresh wheat germ are as shown in Figure 4 and Figure 5 . Compared with fresh wheat germ (such as Figure 4 A in Figure 4 B in Figure 4 C in Figure 4In D). Compared with the unfermented groups (WG group, CON group), natural fermentation (CK group) and WYL8 fermentation (WYL8 group) both decreased the pH value of wheat germ ( P <0.05), but the pH value of the WYL8 group was lower ( P <0.05) (as shown in Figure 5 A). Compared with the original sample of fresh wheat germ (WG group), the total antioxidant capacity (T-AOC) in wheat germ after being treated in three ways for 24 h decreased significantly ( P <0.05), but the T-AOC of the WYL8 treatment group was significantly higher than that of the CON group and the CK group ( P <0.05) (as shown in Figure 5 B); the lipopolysaccharide (LPS) activity decreased to varying degrees after being treated in three ways ( P <0.05), and the LPS activity from high to low was WG > CON > CK > WYL8 (as shown in Figure 5 C); there was no significant difference in the malondialdehyde (MDA) content in wheat germ between the CON group and the CK group ( P >0.05), but both were significantly higher than that of the WG group ( P <0.05). WYL8 fermentation slightly increased the MDA content in wheat germ, but there was no significant difference in the MDA content compared with the WG group ( P >0.05) (as shown in Figure 5 D).

[0075] 2.5 Effects of different treatments on the aerobic storage stability of wheat germ

[0076] After 4 kinds of wheat germ pretreated in different ways were continuously aerobically exposed for 8 h, their appearance changes were as shown in Figure 6 . The color of the samples in the WG, CON and CK groups gradually deepened with the extension of aerobic exposure time. Only the color of the wheat germ after WYL8 treatment was similar to that at the 0 h moment after 8 h of oxygen exposure. Samples after 8 h of aerobic exposure were collected, and the indexes related to lipid oxidation were detected. The results showed that the pH value of the wheat germ pretreated with WYL8 was the lowest after 8 h of aerobic exposure ( P <0.05), and was lower than 4.0 (as shown in Figure 7 A), and the T-AOC was significantly stronger than that of the WG group, the CON group and the CK group ( P <0.05) (as shown in Figure 7 B). Compared with the unfermented groups (WG group, CON group), fermentation pretreatment (CK and WYL8 groups) could keep the LPS activity in wheat germ at a lower level under aerobic exposure conditions, and the LPS activity of the WYL8 group was the lowest ( P <0.05) (as shown in Figure 7 C); however, blank fermentation pretreatment significantly increased the MDA content in wheat germ compared with the two unfermented pretreatment groups (P <0.05), the MDA content in the WYL8 group was significantly lower than that in the other three groups ( P <0.05) (as Figure 7 shown in D).

[0077] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A plant lactobacillus with anti-lipid oxidation function ( Lactiplantibacillus plantarum )WYL8, characterized in that, The Lactobacillus plantarum WYL8 was deposited in the China Center for Type Culture Collection on June 21, 2024, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO: M 20241344.

2. Application of Lactobacillus plantarum WYL8 in wheat germ storage as claimed in claim 1.

3. Use of Lactobacillus plantarum WYL8 as claimed in claim 1 in the preparation of an anti-lipid oxidation preparation.

4. An anti-lipid oxidation preparation, characterized in that: It comprises the Lactobacillus plantarum WYL8 described in claim 1.

5. A method for storing wheat germ using Lactobacillus plantarum WYL8 as claimed in claim 1, characterized in that: The following steps are involved: Lactobacillus plantarum WYL8 was inoculated into wheat germ and sealed and fermented for 24 hours.

6. The method for storing wheat germ according to claim 5, characterized in that: The effective viable count of Lactobacillus plantarum WYL8 is 1.2×10 7 CFU / mL, the inoculation amount of the Lactobacillus plantarum WYL8 is 4% by volume.

7. The method for storing wheat germ according to claim 5, characterized in that: The sealed fermentation is carried out under light-proof conditions, and the temperature of the sealed fermentation is 37°C.

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