Phytobacterium plantarum capable of producing sour bamboo shoot characteristic flavor substance p-cresol through fermentation

Abstract

The invention discloses a plant lactobacillus capable of producing a sour bamboo shoot characteristic flavor substance p-cresol through fermentation, and belongs to the technical field of microorganisms. According to the invention, a strain of plant lactobacillus is screened, characteristic flavor substances p-cresol and organic acid in the sour bamboo shoots can be produced, rapid fermentation of the sour bamboo shoots can be realized, the sour bamboo shoots fermented by the plant lactobacillus can meet the maturity requirement in 15 days, the p-cresol content is 585.03 + / -44.57 mu g / kg, the lactic acid content is 0.60 + / -0.09 g / 100g, the acetic acid content is 0.18 + / -0.01 g / 100g, and the sour bamboo shoots are fermented by the plant lactobacillus. And the method has extremely high application prospects in production of p-cresol, production of organic acids, production of sour bamboo shoots and the like.

Description

Technical Field

[0001] The present invention relates to a Lactiplantibacillus plantarum capable of fermenting to produce p-cresol, a characteristic flavor substance of pickled bamboo shoots, and belongs to the field of microbial technology. Background Art

[0002] Pickled bamboo shoots are made from fresh hemp bamboo shoots, adding spring water, cooled boiled water or a fermentation broth mixed with fermentation mother liquor and water, covering the surface of the bamboo shoots and sealing them with a lid. No seasonings are added during the fermentation period, and they can be eaten after natural fermentation at room temperature.

[0003] As a fermented vegetable, pickled bamboo shoots are popular among the public because of their unique sour and stinky smell. However, the current industrial production of pickled bamboo shoots still continues the traditional natural fermentation. The determination of the maturity of pickled bamboo shoots mostly relies on artificial experience, and the microbial community is complex during the natural fermentation process, and there may be large differences between batches of products.

[0004] Screening excellent lactic acid bacteria from the natural fermentation process of pickled bamboo shoots and preparing them into direct vat inoculants can effectively shorten the fermentation time and stabilize the quality of the fermented products, providing the possibility for large-scale industrial production. Although direct vat inoculation can shorten the fermentation time and increase the lactic acid content to enhance the sour taste of pickled bamboo shoots, it cannot produce p-cresol, a unique stinky substance of pickled bamboo shoots. On the contrary, direct vat inoculation will reduce the content of p-cresol in fermented pickled bamboo shoots (see the master's degree thesis "Research on the production technology of pickled bamboo shoots by direct vat inoculation").

[0005] Therefore, it is very crucial to obtain lactic acid bacteria that can produce high yields of organic acids and flavor substances such as p-cresol to ensure the success rate of pickled bamboo shoot production and improve the flavor of pickled bamboo shoots.

[0006] However, the reported p-cresol-producing strains are from the genus Clostridium (such as Clostridium butyricum or Clostridium tyrobutyricum). For example, Du et al. found that Clostridium butyricum, Clostridium tyrobutyricum, and Clostridium aminovalericum were confirmed to have the ability to produce p-cresol (see the paper "Exploring the microbial origins of p-cresol and its co-occurrence pattern in the Chinese liquor-making process").

[0007] Currently, there are few reports that lactic acid bacteria can produce p-cresol. Therefore, it is urgent to find more dominant strains of pickled bamboo shoot fermentation that can produce organic acids and characteristic flavor substances such as p-cresol to ensure the success rate of pickled bamboo shoot production and improve the flavor of pickled bamboo shoots. Summary of the Invention

[0008] The invention provides a plant lactobacillus (Lactiplantibacillus plantarum) CCFM1419 capable of producing p-cresol and organic acid. The plant lactobacillus (Lactiplantibacillus plantarum) CCFM1419 has been deposited in Guangdong Provincial Microbiological Culture Collection Center on October 31, 2024, with a deposit number of GDMCC No: 65376, and a deposit address of 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0009] In one embodiment, the Lactobacillus plantarum CCFM1419 is isolated from a sour bamboo shoot sample from Guangxi. The 16S rDNA sequence of the strain is shown in SEQ ID NO: 1 through sequencing analysis.

[0010] The invention also provides a starter containing the plant lactobacillus CCFM1419.

[0011] In one embodiment, the preparation method of the starter is: inoculating the plant lactobacillus CCFM1419 into a culture medium for culturing to obtain a culture solution; centrifuging the culture solution to obtain bacterial cells; resuspending the bacterial cells with a buffer solution and a cryoprotectant to obtain a resuspension; and vacuum freeze-drying the resuspension to obtain a starter.

[0012] In one embodiment, the leavening agent is a sour bamboo shoot leavening agent.

[0013] In one embodiment, the starter culture contains living cells of Lactobacillus plantarum CCFM1419.

[0014] In one embodiment, the number of Lactobacillus plantarum CCFM1419 in the starter is ≥ 1×10 7 CFU / mL.

[0015] The present invention also provides a method for preparing p-cresol, which comprises first inoculating the plant lactobacillus CCFM1419 into a fermentation medium containing p-hydroxybenzyl alcohol for fermentation to obtain a fermentation liquid, and then extracting p-cresol from the fermentation liquid.

[0016] The present invention also provides a method for preparing sour bamboo shoots, wherein the plant lactobacillus CCFM1419 or the starter is inoculated into fresh bamboo shoots for anaerobic fermentation.

[0017] In one embodiment, the fermentation temperature is 20-30° C., and the fermentation lasts for at least 15 days.

[0018] In one embodiment, the bamboo shoots are bamboo shoots.

[0019] The present invention also provides pickled bamboo shoots prepared by using the said method.

[0020] The present invention also provides the application of the Lactiplantibacillus plantarum CCFM1419, or the said starter, or the said method in the preparation of fermented products.

[0021] In one embodiment, the fermented product is a fermented vegetable product.

[0022] Beneficial effects:

[0023] The present invention has screened out a strain of Lactiplantibacillus plantarum CCFM1419, which can rapidly ferment pickled bamboo shoots and meet the standard of mature pickled bamboo shoots in 15 days, and can produce the characteristic flavor substances p - cresol and organic acids of pickled bamboo shoots. Specifically, it is reflected in:

[0024] (1) When this Lactiplantibacillus plantarum CCFM1419 is inoculated into pickled bamboo shoot raw materials for fermentation, after 3 days of fermentation, the pH value of the pickled bamboo shoots can be reduced to 3.65, and after 30 days of fermentation, the total acid content in the pickled bamboo shoots can reach as high as 3.02 g / 100 g;

[0025] (2) When this Lactiplantibacillus plantarum CCFM1419 is inoculated into pickled bamboo shoot raw materials for fermentation, after 30 days of fermentation, the p - cresol content in the pickled bamboo shoots can reach 1294.00 ± 92.37 μg / kg;

[0026] (3) When this Lactiplantibacillus plantarum CCFM1419 is inoculated into pickled bamboo shoot raw materials for fermentation, after 30 days of fermentation, the lactic acid content in the pickled bamboo shoots can reach as high as 0.46 g / 100 g, and the acetic acid content in the pickled bamboo shoots can reach as high as 0.19 g / 100 g;

[0027] Therefore, the Lactiplantibacillus plantarum CCFM1419 of the present invention has extremely high application prospects in aspects such as the production of p - cresol, the production of organic acids, and the production of pickled bamboo shoots.

[0028] Biological material preservation

[0029] Lactiplantibacillus plantarum CCFM1419, taxonomically named Lactiplantibacillus plantarum, has been deposited in the Guangdong Provincial Culture Collection of Microorganisms on October 31, 2024, with the deposit number GDMCC No: 65376, and the deposit address is on the 5th floor of Building 59, No. 100 compound, Xianlie Middle Road, Guangzhou. Description of the drawings

[0030] Figure 1Colony characteristics of Lactiplantibacillus plantarum CCFM1419.

[0031] Figure 2 Cell characteristics of Lactiplantibacillus plantarum CCFM1419.

[0032] Figure 3 Salt tolerance of Lactiplantibacillus plantarum CCFM1419.

[0033] Figure 4 p - Cresol content in pickled bamboo shoots obtained by inoculated fermentation and natural fermentation.

[0034] Figure 5 pH value in pickled bamboo shoots obtained by inoculated fermentation and natural fermentation.

[0035] Figure 6 Total acid content in pickled bamboo shoots obtained by inoculated fermentation and natural fermentation.

[0036] Figure 7 Lactic acid content in pickled bamboo shoots obtained by inoculated fermentation and natural fermentation.

[0037] Figure 8 Acetic acid content in pickled bamboo shoots obtained by inoculated fermentation and natural fermentation.

[0038] Figure 9 Comparison of p - cresol content in the fermentation broth of Lactiplantibacillus plantarum CCFM1419 and Lactiplantibacillus plantarum CCFM427. Detailed implementation mode

[0039] The present invention will be further elaborated below in conjunction with specific embodiments and drawings.

[0040] The Dendrocalamus latiflorus Munro used in the following examples was purchased from Wuxi Auchan Supermarket.

[0041] The culture media involved in the following examples are as follows:

[0042] MRS solid medium: peptone 10 g / L, beef extract 10 g / L, glucose 20 g / L, sodium acetate 2 g / L, yeast powder 5 g / L, diammonium citrate 2 g / L, K2HPO4·3H2O 2.6 g / L, MgSO4·7H2O 0.1 g / L, MnSO4·H2O 0.05 g / L, Tween 80 1 mL / L, agar powder 15 g / L, cysteine hydrochloride 0.5 g / L.

[0043] MRS liquid medium: peptone 10 g / L, beef extract 10 g / L, glucose 20 g / L, sodium acetate 2 g / L, yeast powder 5 g / L, diammonium hydrogen citrate 2 g / L, K2HPO4·3H2O 2.6 g / L, MgSO4·7H2O 0.1 g / L, MnSO4·H2O 0.05 g / L, Tween 80 1 mL / L, cysteine hydrochloride 0.5 g / L.

[0044] MRS - p - hydroxybenzyl alcohol medium: p - hydroxybenzyl alcohol is added to the MRS medium at a final concentration of 0.02 mmol / L.

[0045] The detection methods involved in the following examples are as follows:

[0046] Detection method for p - hydroxybenzyl alcohol and p - cresol contents:

[0047] Weigh 100 g of the pickled bamboo shoot sample, homogenize it in 200 mL of pure water, sonicate for 30 min, centrifuge at 8000 r / min for 20 min, and collect the supernatant; filter 1 mL of the sample through a microporous membrane with a pore size of 0.45 μm, and then use the obtained filtrate for reverse - phase high - performance liquid chromatography (RP - HPLC) analysis. Use a BEH C18 chromatographic column. Mobile phase A: glacial acetic acid: water (v / v = 1:99); Mobile phase B: glacial acetic acid: acetonitrile: aqueous solution (v / v = 1:30:69). Gradient elution: 80%A + 20%B (0 min - 16 min); 40%A + 60%B (16 min - 23 min); 25%A + 75%B (23 min - 34 min); 100%B (34 min - 50 min).; Set the fluorescence detection wavelength gradient: 0 min, excitation wavelength is 284 nm, emission wavelength is 333 nm; 5 min, excitation wavelength is 275 nm, emission wavelength is 315 nm; 8 min, excitation wavelength is 277 nm, emission wavelength is 319 nm; 12 min, excitation wavelength is 272 nm, emission wavelength is 310 nm; 25 min, excitation wavelength is 273 nm, emission wavelength is 312 nm. Column temperature: 30 °C; Column flow rate: 1 mL / min; Injection volume: 20 μL.

[0048] Detection method for pH value: Weigh 100 g of the pickled bamboo shoot sample, homogenize it in 200 mL of pure water, sonicate for 30 min, centrifuge at 8000 r / min for 20 min, and collect the supernatant; take 5 mL of the juice and measure the pH of the pickled vegetables with a pH meter.

[0049] Detection method for total acid content: Weigh 100 g of pickled bamboo shoot samples, homogenize them in 200 mL of pure water, ultrasonicate for 30 min, centrifuge at 8000 r / min for 20 min, and collect the supernatant. Take 25 mL of the sample and determine the total acid content according to the acid-base titration method. The specific operation method refers to the national standard GB / T 12456—2008 "Determination of Total Acid in Foods".

[0050] Detection method for lactic acid and acetic acid content: Take 1 mL of the sample and filter it through a 0.22 μm microporous membrane, and place the filtrate in a liquid phase vial. Use HPLC to determine the content of 10 organic acids. The chromatographic column is AtlantisTM T3, mobile phase A: methanol: water: H3PO4 = 80:20:0.05; mobile phase B: methanol: water: H3PO4 = 5:95:0.05. The gradient elution program is as follows: 0 min - 5 min, 100% B; 5 min - 10 min, 5% A + 95% B; 10 min - 30 min, 95% A + 5% B; 30 min - 35 min, 100% A; 35 min - 45 min, 100% A; 45 min - 51 min, 100% B; 51 min - 66 min, 100% B. The ultraviolet detection wavelength is 210 nm. Quantify according to the standard curve of each organic acid.

[0051] Example 1: Screening, identification and preservation of p-cresol-producing strains

[0052] 1. Screening

[0053] Using pickled bamboo shoot juice from Guangxi as a sample, perform 10-fold serial dilutions with sterile saline to 10 -3 , and then take 100 μL of the diluted solutions with dilution factors of 10 -1 , 10 -2 , 10 -3 and spread them on MRS solid medium for plate coating. Incubate in an inverted position at 37 °C for 48 h, observe and record the colony morphology; pick colonies with different morphologies on the MRS solid medium for streak isolation. After static incubation at 37 °C for 48 h, pick different single colonies with different morphologies on the MRS solid medium again for streak isolation until pure single colonies with consistent morphology are obtained; observe the colony morphology of the single colonies, and select strains with small, round, milky white, convex, smooth colony morphology, spherical cell morphology, and positive Gram staining results, and name them respectively: CCS11, CCS12, CCFM1419, CCS14, CCS15, CCS16, CCS17, CCS18, CCS19, CCS20.

[0054] A decrease in the content of p-hydroxybenzyl alcohol and an increase in the content of p-cresol were found in fresh bamboo shoots and fermented sour bamboo shoots. Through KEGG, the pathway of p-cresol was explored, and it was considered that a certain dehydroxylase of the strain caused p-hydroxybenzyl alcohol to lose its hydroxyl group and become p-cresol. That is, p-hydroxybenzyl alcohol was considered to be the precursor of p-cresol, a characteristic flavor substance of sour bamboo shoots.

[0055] Therefore, the 10 strains screened were respectively inoculated into MRS (MRS-p-hydroxybenzyl alcohol medium) supplemented with p-hydroxybenzyl alcohol, and at the same time, the 10 strains were inoculated into MRS as a control group. They were cultured in a constant temperature incubator at 37°C for 14 h, and p-cresol and p-hydroxybenzyl alcohol in the fermentation supernatant were determined. The final results showed that no p-cresol was produced in the single MRS medium, while 1 strain of Lactobacillus (CCFM1419) that could produce p-cresol was screened in the MRS-p-hydroxybenzyl alcohol medium with p-hydroxybenzyl alcohol as the substrate. The results of strain screening are listed in Table 1.

[0056] Table 1 Contents of p-hydroxybenzyl alcohol and p-cresol in the fermentation broth of each strain

[0057]

[0058] For microscopic examination of strain CCFM1419, the microscopic examination method was as follows: Take a clean glass slide, heat it slightly on the flame and then cool it; after cooling, add a small drop of sterile water in the central part of the clean glass slide, and use an inoculation loop to pick up a small amount of bacteria from a single colony beside the flame and mix it with the water; burn off the excess bacteria on the inoculation loop, and then use the inoculation loop to spread the bacteria into a uniform thin layer with a diameter of 1 cm; after the uniform thin layer on the clean glass slide dries naturally, heat it on a gentle fire 3-4 times for fixation; add 1-2 drops of crystal violet solution to the smear, stain for 1 min; gently wash off the stain with water, and gently blot the water on the glass slide with absorbent paper; add 1-2 drops of iodine solution to the smear, stain for 1 min, gently wash off the stain with water, and gently blot the water on the glass slide with absorbent paper; add 1-2 drops of 95% (v / v) ethanol solution to the smear, decolorize for 5-15 s, gently rinse with water, and gently blot the water on the glass slide with absorbent paper; add 1-2 drops of safranin solution to the smear, stain for 2 min, and after drying, perform microscopic examination with a microscope to observe the bacterial morphology;

[0059] The Gram staining method refers to the textbook "Industrial Microbiology Breeding" (author: Zhuge Jian); the method for investigating physiological and biochemical characteristics refers to the textbook "Handbook for Systematic Identification of Common Bacteria" (author: Dong Xiuzhu). The colony characteristics of strain CCFM1419 are as Figure 1 shown, and the bacterial characteristics are as Figure 2 shown.

[0060] Pick a single colony of Lactiplantibacillus plantarum CCFM1419 and inoculate it into MRS liquid medium. Incubate statically at 37 °C for 20 - 24 h to obtain a bacterial solution. Take 1 mL of the bacterial solution and place it in a bacteria preservation tube. Centrifuge at 6000 rpm for 3 min, then discard the supernatant. Resuspend the bacterial pellet in 30% (v / v) glycerol solution and store it at -80 °C.

[0061] 2. Identification

[0062] Extract the genome of strain CCFM1419, amplify and sequence the 16S rDNA of strain CCS3 (sequencing was performed by BGI. Among them, the nucleotide sequence of the 16S rDNA amplification of strain CCFM1419 is shown in SEQ ID NO: 1, and the primers used for amplification are 27F (AGAGTTTGATCMTGGCTCAG) and 1492R (GGTTACCTTGTTACGACTT)). Compare the sequenced sequence with the nucleic acid sequences in NCBI. The results show that strain CCS3 is Lactiplantibacillus plantarum, and it is named Lactiplantibacillus plantarum CCFM1419.

[0063] Example 2: Evaluation of the acid and salt tolerance of Lactiplantibacillus plantarum producing p - cresol

[0064] 1. Acid tolerance

[0065] Streak Lactiplantibacillus plantarum CCFM1419 obtained in Example 2 on MRS solid medium and culture at 37 °C for 48 h to obtain single colonies. Pick single colonies and inoculate them into MRS liquid medium respectively, and culture at 37 °C for 18 h for activation, and activate for three generations continuously. Use HCl to adjust the pH of the MRS liquid medium to 3.0 respectively. Inoculate the activated Lactiplantibacillus plantarum CCFM1419 into the MRS liquid with a pH of 3.0 at an inoculation amount of 2% (V / V), mix well, then incubate at a constant temperature of 37 °C for 3 h, dilute with physiological saline, take 1 mL of the bacterial solution at an appropriate dilution gradient and pour it, and measure the viable bacteria count. Take the viable bacteria count at 0 h as the control group, and calculate the survival rate of the strain at pH 3.0. The formula for calculating the survival rate of the strain is as follows:

[0066] Acid tolerance survival rate = N2 / N1 × 100%;

[0067] Among them, N1 is the viable bacteria count (CFU / mL) at 0 h; N2 is the viable bacteria count (CFU / mL) after 3 h of acid treatment;

[0068] The results show that the survival rate of Lactiplantibacillus plantarum CCFM1419 after 3 h of treatment in the acidic MRS medium with a pH of 3 is 15.83%.

[0069] 2. Salt tolerance

[0070] The activated Lactiplantibacillus plantarum CCFM1419 was inoculated into MRS liquid medium containing 3 g / 100 mL, 6 g / 100 mL, and 9 g / 100 mL NaCl at an inoculation amount of 2% (V / V) respectively, cultured at a constant temperature of 37 °C for 3 h, diluted with physiological saline, 1 mL of the bacterial liquid at an appropriate dilution gradient was taken, and the viable count was determined by the plate pouring method. The formula for calculating the survival rate of the strain is as follows:

[0071] Salt tolerance survival rate = N2 / N1 × 100%;

[0072] Among them, N1 is the viable count (CFU / mL) at 0 h; N2 is the viable count (CFU / mL) after 3 h of salt treatment.

[0073] The results showed ( Figure 3 ), the survival rates of Lactiplantibacillus plantarum CCFM1419 in MRS liquid medium containing 3 g / 100 mL, 6 g / 100 mL, and 9 g / 100 mL NaCl were 111.61%, 134.79%, and 116.35% respectively.

[0074] Example 3: Production of p-cresol, a characteristic flavor substance of pickled bamboo shoots

[0075] The Lactiplantibacillus plantarum CCFM1419 obtained in Example 2 was streaked on MRS solid medium respectively and cultured at 37 °C for 48 h to obtain single colonies; the single colonies were picked and inoculated into MRS liquid medium respectively, cultured at 37 °C for 18 h for activation, and activated continuously for three generations. Finally, it was expanded in a 100 mL blue-capped bottle. After culturing to the logarithmic phase, it was immediately taken out, centrifuged at 8000 r / min at 4 °C for 20 min, the supernatant was discarded, the bacterial sludge was washed with 0.9% (w / v) physiological saline, centrifuged at 8000 r / min at 4 °C for 20 min, the bacterial sludge was collected, and the bacterial sludge was resuspended with 0.9% (w / v) physiological saline; the fresh bamboo shoots were peeled and washed and then put into a pickling tank, and pure water was added to cover the fresh bamboo shoots. The test strain was added to the pickling tank at a final concentration of 1×10 7 CFU / mL, stirred evenly, covered with a pickling lid and sealed with water for fermentation. At the same time, according to the above process, no strain was inoculated, and pure water was directly added to ferment pickled bamboo shoots as a control group for natural fermentation with clear water, and fermented for 30 days.

[0076] During the fermentation process, inoculated fermentation and water-only fermentation of pickled bamboo shoots were collected on the 0th, 1st, 3rd, 6th, 15th, 21st, and 30th days of fermentation respectively. The inoculated fermentation samples were labeled as 0, Z1, Z3, Z6, Z15, Z21, Z30; the water-only fermentation samples were labeled as 0, Q1, Q3, Q6, Q15, Q21, Q30. Samples were collected and mixed from three sampling points from the top to the bottom of the fermentation tank. The content change of p-cresol in pickled bamboo shoots was regularly detected, and when the p-cresol in pickled bamboo shoots reached 500 μg / kg, it was considered that the pickled bamboo shoots were fermented to maturity.

[0077] It can be seen from Figure 4 that compared with natural fermentation, Lactiplantibacillus plantarum CCFM1419 has a stronger ability to produce p-cresol. On the 15th day of fermentation, the content of p-cresol in the pickled bamboo shoots fermented by Lactiplantibacillus plantarum CCFM1419 reached as high as 585.03 μg / kg, which could meet the maturity standard; on the 30th day of fermentation, the content of p-cresol in this pickled bamboo shoots reached as high as 1294.12 μg / kg, while the content of p-cresol in the pickled bamboo shoots obtained by natural fermentation was only 263.58 μg / kg. At the same time, flavor substances such as acetophenone, methyl salicylate, and 2-pentylfuran were also produced in the pickled bamboo shoots fermented by Lactiplantibacillus plantarum CCFM1419; among them, 2-pentylfuran can be used as a flavor component in the food and fragrance industries, providing flavors similar to nuts, roasted aroma, etc.; acetophenone can be used in the synthesis of drugs, spices, dyes, etc.; methyl salicylate has the fragrance of wintergreen leaves and anti-inflammatory and analgesic properties, and can also regulate the stratum corneum.

[0078] Example 4: Production of organic acids, the characteristic flavor substances of pickled bamboo shoots

[0079] Lactiplantibacillus plantarum CCFM1419 obtained in Example 2 was streaked on MRS solid medium respectively and cultured at 37 °C for 48 h to obtain single colonies; single colonies were picked and inoculated into MRS liquid medium respectively, cultured at 37 °C for 18 h for activation, and activated for three consecutive generations. Finally, it was expanded in a 100 mL blue-capped bottle containing MRS medium. After culturing to the logarithmic phase, it was immediately taken out, centrifuged at 8000 r / min at 4 °C for 20 min, the supernatant was discarded, the bacterial sludge was washed with 0.9% (w / v) physiological saline, centrifuged at 8000 r / min at 4 °C for 20 min, the bacterial sludge was collected, and the bacterial sludge was resuspended with 0.9% (w / v) physiological saline; the fresh bamboo shoots were peeled and washed and then put into a pickling tank, added with pure water to cover the fresh bamboo shoots, and the test strain was added to the pickling tank to make the final concentration of the inoculated strain 1×10 7 CFU / mL, stirred evenly, covered with a pickling lid and sealed with water for fermentation. At the same time, according to the above process, without strain inoculation, pure water was directly added to ferment pickled bamboo shoots as a water-only natural fermentation control group, and fermented for 30 days.

[0080] During the fermentation process, samples of pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 and pickled bamboo shoots fermented with water were taken on the 0th, 1st, 3rd, 6th, 15th, 21st, and 30th days of fermentation. The inoculated fermentation samples were labeled as 0, Z1, Z3, Z6, Z15, Z21, Z30; the water-fermented samples were labeled as 0, Q1, Q3, Q6, Q15, Q21, Q30. Samples were collected and mixed from three sampling points from the top to the bottom of the fermenter. The pH value, total acid content, and lactic acid and acetic acid contents of the pickled bamboo shoots were regularly detected. When the above indicators in the pickled bamboo shoots reached 4.5, 2.7 g / 100 g, 0.58 g / 100 g, and 0.18 g / 100 g respectively, the pickled bamboo shoots were considered to be fermented to maturity.

[0081] It can be seen from Figure 5 that compared with natural fermentation, the pH of the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 decreased faster. At 1 day of fermentation, the pH value of the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 decreased to 4.24, which could meet the maturity standard. While the pH value of the pickled bamboo shoots obtained by natural fermentation only decreased to 4.23 at 3 days of fermentation.

[0082] It can be seen from Figure 6 that compared with natural fermentation, the total acid content in the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 was higher. At 3 days of fermentation, the total acid content in the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 could reach 2.70 g / 100 g, which could meet the maturity standard. At 30 days of fermentation, the total acid content in the pickled bamboo shoots obtained by inoculated fermentation was as high as 3.02 g / 100 g, while the total acid content in the pickled bamboo shoots obtained by natural fermentation was only 1.27 g / 100 g and still did not reach the standard.

[0083] It can be seen from Figure 7 that compared with natural fermentation, Lactiplantibacillus plantarum CCFM1419 had a stronger ability to produce lactic acid. At 3 days of fermentation, the lactic acid content in the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 could reach 0.77 g / 100 g, which could meet the maturity standard. At 30 days of fermentation, the lactic acid content in the pickled bamboo shoots obtained by natural fermentation was only 0.18 g / 100 g and still did not reach the maturity standard.

[0084] It can be seen from Figure 8 that compared with natural fermentation, Lactiplantibacillus plantarum CCFM1419 had a stronger ability to produce acetic acid. At 3 days of fermentation, the acetic acid content in the pickled bamboo shoots fermented with Lactiplantibacillus plantarum CCFM1419 was as high as 0.19 g / 100 g, while the lactic acid content in the pickled bamboo shoots obtained by natural fermentation was only 0.07 g / 100 g at 30 days of fermentation and still did not reach the maturity standard.

[0085] Comparative example 1:

[0086] The specific implementation manners are the same as those in Examples 3 to 4, except that the strain is replaced with Lactobacillus plantarum CCFM427 preserved in the laboratory, and the results show that p-cresol is not detected in the fermented sample solution (such as Figure 9 ).

[0087] Comparative Example 2:

[0088] The specific implementation manners are the same as those in Examples 3 to 4, except that the bacterial liquid is replaced with an equal amount of clear water, and the results show that the content of p-cresol in the sample solution obtained after 30 days of fermentation is 263.58 ± 35.81 μg / kg.

[0089] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with this technology can make various modifications and decorations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. Lactiplantibacillus plantarum CCFM1419 was deposited at the Guangdong Microbial Culture Collection Center on October 31, 2024, with the deposit number GDMCC No: 65376.

2. A starter culture containing Lactiplantibacillus plantarum CCFM1419 as claimed in claim 1.

3. The starter culture according to claim 2, characterized in that, The starter culture contains live cells of Lactiplantibacillus plantarum CCFM1419.

4. A method for preparing the starter culture according to claim 2 or 3, characterized in that, Inoculate Lactiplantibacillus plantarum CCFM1419 as claimed in claim 1 into a culture medium for cultivation to obtain a culture solution; centrifuge the culture solution to obtain bacterial cells; resuspend the bacterial cells with a buffer and a cryoprotectant to obtain a resuspended solution; vacuum freeze-dry the resuspended solution to obtain a starter culture.

5. A method for preparing p-cresol, characterized in that, First, inoculate Lactiplantibacillus plantarum CCFM1419 as claimed in claim 1 into a fermentation medium containing p-hydroxybenzyl alcohol for fermentation to obtain a fermentation broth, and then extract p-cresol from the fermentation broth.

6. A method for preparing pickled bamboo shoots, characterized in that, Inoculate Lactiplantibacillus plantarum CCFM1419 as claimed in claim 1 or the starter culture as claimed in any one of claims 2 to 3 into a liquid environment containing fresh bamboo shoots for anaerobic fermentation.

7. The method according to claim 6, wherein The temperature of the fermentation is 20 - 30 °C and the fermentation lasts for at least 15 days.

8. The method according to claim 6 or 7, characterized in that, The bamboo shoots are Dendrocalamus latiflorus Munro.

9. Pickled bamboo shoots prepared by the method as claimed in any one of claims 6 to 8.

10. Use of Lactiplantibacillus plantarum CCFM1419 as claimed in claim 1, or the starter culture as claimed in any one of claims 2 to 3, or the method as claimed in any one of claims 5 to 8 in the preparation of fermented products.

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