Weissella sinus and application of Weissella sinus in promoting generation of fruity flavor substances in fermented food

Abstract

The invention discloses Weissella sinus and an application of the Weissella sinus in promoting production of fruity flavor substances in fermented soybean milk, and belongs to the technical field of food microorganisms. The Weissella cibaria GDMCC 66672 not only has excellent growth ability and acid production ability in fermented soybean milk, but also can produce various fruit flavor substances in high yield in the soybean milk fermentation process, so that beany flavor substances in the soybean milk are effectively reduced. When the strain is prepared into a microbial inoculum to be applied to the production process of low-temperature fermented soybean milk, the quality and flavor of the fermented soybean milk can be remarkably improved. The strain disclosed by the invention is good in practical application effect and has a good application prospect in low-temperature fermented soybean milk production.

Description

TECHNICAL FIELD

[0001] The present application relates to a strain of Weissella cibaria and its application in promoting the production of fruit flavor substances in fermented food, belonging to the field of food microbiology technology. BACKGROUND

[0002] Soy milk is a plant-based dairy product made from soybeans, rich in protein, unsaturated fat, vitamins and minerals, and is a high-nutrition plant protein beverage. However, the soybean flavor in soy milk is not easily accepted by consumers, and it is difficult to remove during processing, affecting the flavor and quality of the final product and limiting the development of soy milk products.

[0003] Compared with soy milk, fermented soy milk has a more perfect nutritional structure and is easily digested and absorbed by the human body. Soy milk is rich in nutrients and is an ideal culture medium for lactic acid bacteria. Various microorganisms belonging to lactic acid bacteria have been used to reduce or mask the off-flavor of soy products. Not only can it remove the soybean flavor, but it can also produce unique flavor characteristics. The off-flavor of soy milk is mainly caused by volatile compounds, and the concentration of volatile components determines the composition of the final off-flavor. These odor compounds are mainly produced by the enzymatic and non-enzymatic oxidation of unsaturated fatty acids, resulting in soy flavor, grassy flavor, fatty flavor and other off-flavors. Lactic acid bacteria fermentation can degrade aldehydes in soy milk, produce pleasant aroma, reduce the unique flavor of soybeans, and also reduce the oligosaccharides that can cause intestinal gas. In addition, it also converts lactose into organic acids, which helps to bring a refreshing taste. These ketones, alcohols and organic acids substances together give fermented soy milk different fruit, floral and creamy aromas, thereby significantly reducing the soybean flavor of soy milk and improving its aroma quality.

[0004] Low-temperature fermented milk is increasingly favored by consumers due to its delicate texture and better flavor, mainly because low-temperature fermented milk avoids the quality problems such as rough texture, whey separation and insufficient flavor caused by high-temperature short-time fermentation. The longer fermentation process is beneficial to the accumulation of small molecules, the maintenance of viable counts and the improvement of sensory quality. The slow growth of viable counts caused by low inoculation temperature helps to extend the logarithmic phase and stationary phase of lactic acid bacteria, resulting in increased accumulation of exopolysaccharides and other secondary metabolites. SUMMARY

[0005] Weissella cibaria can better utilize sucrose, raffinose and stachyose in soy milk, and has no soybean flavor and unpleasant odor during low-temperature fermentation of soy milk, with a mellow and rich aroma and light acidity. Therefore, screening Weissella cibaria with good fermentation performance in soy milk and producing pleasant flavor is crucial for improving the quality of fermented soy milk.

[0006] The application discloses a Weissella cibaria, which is used as a fermenting agent for low-temperature fermented soy milk to promote the production of fruity flavor substances, improve the flavor of the fermented soy milk, and improve the quality of the fermented soy milk, and has a wide application prospect.

[0007] Based on the above problems, the application provides a Weissella cibaria, which is characterized in that the Weissella cibaria MXJSHZ8-3 has been preserved in the Guangdong Provincial Microbial Culture Collection Center on July 14, 2025, has a preservation number of GDMCC 66672, and has a preservation address of No. 59 Building, 5th Floor, 100, Martyrs' Avenue, Guangzhou.

[0008] The second object of the application is to provide a fermenting agent containing the above-mentioned Weissella cibaria MXJSHZ8-3.

[0009] In an embodiment, the fermenting agent is a direct-vat fermentation agent, and the preparation method is as follows: the Weissella cibaria MXJSHZ8-3 is activated and cultured to a viable bacterial concentration of more than 10 8 cfu / mL, then centrifuged, washed with a buffer, added with a freeze-drying protective agent, adjusted to a viable bacterial concentration of more than 10 9 cfu / mL, vacuum freeze-dried, and the direct-vat fermentation agent is obtained after freeze-drying.

[0010] In an embodiment, the buffer is physiological saline.

[0011] The third object of the application is to provide the application of the above-mentioned Weissella cibaria MXJSHZ8-3 or the above-mentioned fermenting agent in fermented food.

[0012] In an embodiment, the fermented food includes fermented fruit and vegetable juice, fermented milk, fermented pickles or fermented soy milk.

[0013] In an embodiment, the fermented soy milk includes sour soy milk and fermented soy milk beverage.

[0014] In an embodiment, the fermented food produced by using the Weissella cibaria MXJSHZ8-3 or the fermenting agent containing the Weissella cibaria MXJSHZ8-3 has one or more flavor substances of alcohols, acids, aldehydes, phenols or furans.

[0015] In an embodiment, the alcohol includes octanol, 2-heptanol, isoamylene alcohol, cis-2-pentenol, n-hexanol, leaf alcohol, 3-octanol, 2-decene-1-alcohol, 2-ethylhexanol, trans-2-heptene-1-alcohol, trans-2-octene-1-alcohol, 1-nonanol, benzyl alcohol or phenethyl alcohol; the acid includes acetic acid, propionic acid, 3-methyl pentanoic acid, butyric acid, hexanoic acid, octanoic acid, n-nonanoic acid, heptanoic acid, myristic acid or palmitic acid; the aldehyde includes n-pentanal, n-hexanal, 2,4-dimethylbenzaldehyde, n-octanal, benzaldehyde, 2-heptanone, 3-octanone, 1-heptene-3-ketone, methyl heptenone, 2-nonanone, 1-(3-hydroxy-2-furyl) ethanone or phenylacetone, the phenol includes methyl maltol; and the furan includes 2-pentylfuran.

[0016] In an embodiment, the fermentation temperature of the fermented soy milk is 25℃.

[0017] In an embodiment, the amount of the ferment added in the soy milk is 2-5% of the mass of the soy milk.

[0018] In an embodiment, the preparation method of the fermented soy milk is as follows: 50-200 g of dry soybeans are weighed and soaked overnight, the soaked soybeans are peeled, water is added in a mass ratio of 1:5-10 to the dry soybeans, the soy milk is ground by a soy milk machine in a thick soy milk mode, the soy milk is ground by a colloid mill for 5 min, the soy milk is filtered by a 150-200 mesh filter after cooling, the soy milk is sterilized at 115℃ for 15 min, and the soy milk is cooled to 15℃-35℃; 2%-5% of the ferment or 10 8 ~10 9 The fermented soy milk is fermented at 25℃ for 10-12 h, and then is matured at 4℃ for 24 h-48 h.

[0019] The present application has the following advantages: 1. The method of the present application is safe and healthy: the Weissella cibaria MXJSHZ8-3 used in the present application is a safe strain for food, which is screened from dried mutton. The method of the present application does not add other chemicals, and is safe and healthy.

[0020] 2. The *Westernella esculenta* MXJSHZ8-3 of this invention can effectively increase the content of fruit flavor substances in low-temperature fermented soy milk, which is beneficial to improving the product quality characteristics. This strain effectively utilizes raffinose, stachyose, and sucrose for soy milk fermentation, produces acid rapidly, reaches the fermentation endpoint quickly, and significantly increases the content of fruity flavor compounds in fermented soy milk: 2-pentylfuran 251.570 μg / kg, 2-heptanone 5.940 μg / kg, 3-octanone 5.457 μg / kg, 1-(3-hydroxy-2-furanyl)acetone 22.595 μg / kg, 1-nonanol 16.645 μg / kg, 2,4-dimethylbenzaldehyde 30.827 μg / kg, benzaldehyde 34.839 μg / kg, myristic acid 10.852 μg / kg, and octanol 14.109 μg / kg, providing a fruity aroma to the fermented soy milk. The fermented soy milk also exhibits high levels of floral flavor compounds phenethyl alcohol and methyl maltol, at 3.816 μg / kg and 15.315 μg / kg, respectively. μg / kg; in addition, the content of hexanal, a substance related to the fishy smell of soy milk, was also low, at 7.324 μg / kg, thus this strain is beneficial to improving the flavor of soy milk.

[0021] Preservation of biological materials Weissella cibaria MXJSHZ8-3, taxonomically named, was deposited on July 14, 2025, at the Guangdong Provincial Center for Microbial Culture Collection, located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, with accession number GDMCC 66672. Attached Figure Description

[0022] Figure 1 Colony morphology of *Westernella glutinis* MXJSHZ8-3.

[0023] Figure 2 A microscopic image of Gram-stained strain of *Westernella taurida* MXJSHZ8-3 under a 1000x microscope.

[0024] Figure 3 The growth of *Westernella taurida* MXJSHZ8-3 and *Westernella taurida* BNCC359725 in soy milk.

[0025] Figure 4 pH changes during soybean milk fermentation by *Westernella taurida* MXJSHZ8-3 and *Westernella taurida* BNCC359725.

[0026] Figure 5 The titratable acid content of *Westernella taurizoides* MXJSHZ8-3 and *Westernella taurizoides* BNCC359725 after fermentation in soy milk was determined.

[0027] Figure 6 The content of aroma volatiles after fermentation of soy milk by *Westernella taurida* MXJSHZ8-3 and *Westernella taurida* BNCC359725 was determined.

[0028] Figure 7 The content of volatile substances with beany odor after fermentation of soy milk by *Westernella taurida* MXJSHZ8-3 and *Westernella taurida* BNCC359725.

[0029] Figure 8 OD of *Westernella taurizoides* MXJSHZ8-3 cultured in MRS medium containing sucrose, raffinose, and stachyose as the sole glycogen for 0-24 hours. 600 Difference. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] MRS broth culture medium: 10 g peptone, 10 g beef extract, 5 g yeast extract, 20 g glucose, 5 g sodium acetate, 2 g diammonium hydrogen citrate, 2 g dipotassium hydrogen phosphate, 0.58 g magnesium sulfate heptahydrate, 0.25 g manganese sulfate monohydrate, 1 mL Tween 80, and 10 g trypone, dissolved in 1 L of water, and adjusted to pH 6.2.

[0032] MRS solid culture medium: 10 g peptone, 10 g beef extract, 5 g yeast extract, 20 g glucose, 5 g sodium acetate, 2 g diammonium hydrogen citrate, 2 g dipotassium hydrogen phosphate, 0.58 g magnesium sulfate heptahydrate, 0.25 g manganese sulfate monohydrate, 1 mL Tween 80, 10 g trypone, and 18 g agar, dissolved in 1 L of water, and adjusted to pH 6.2.

[0033] The control strain, *Westernella tamariscina* BNCC359725, was purchased from BNCC.

[0034] Example 1: Method for isolation and identification of *Westernella esculenta* strain MXJSHZ8-3 (1) Prepare a suitable sample dilution gradient and incubate. Remove the Xinjiang Shihezi air-dried mutton glycerol sample stored at -80℃ and thaw it on ice. After vortexing and mixing, add 0.5 mL of the sample to 4.5 mL of sterile physiological saline to complete the first 10-fold dilution. After vortexing and mixing, add another 0.5 mL of the diluted solution to 4.5 mL of sterile physiological saline to complete the second 10-fold dilution, and so on, until the final dilution is 10-fold. -6Take 200 μL from each gradient dilution and evenly spread on MRS solid medium plates, invert, and incubate at 25 ℃ anaerobically for 36-48 h and observe in time.

[0035] (2) Line separation and purification After taking out the plate with growing colonies, select the gradient plate with single colony and pick up colonies with different colony morphology for secondary line separation until all single colonies are purified.

[0036] (3) Gram staining Pick up single colonies on a glass slide, and after smearing, drying, fixing, primary staining, washing, medium staining, washing, decolorizing, re-staining, washing, drying, and microscopic examination, record the results of Gram staining.

[0037] (4) Strain preservation After the purification of each strain is completed, pick up single colonies into 10 mL liquid MRS medium, and incubate at 25 ℃ for 20-24 h. Take 1 mL of bacterial liquid and centrifuge at 6000 rpm for 3 min. Discard the supernatant, add 1 mL of 60% sterile glycerol solution, resuspend, and store at -80 ℃.

[0038] (5) 16S rDNA sequence amplification Centrifuge 1 mL of bacterial liquid at 6000 rpm for 3 min, discard the supernatant, add 1 mL of sterile water to wash the bacterial cells, centrifuge at 10000 rpm to discard the supernatant, obtain the bacterial slurry, resuspend with 200 uL of sterile water as a template, and perform PCR amplification with the following process: 1) Amplification system 20 μL: Among them, the template amount is 0.5 μL, the bidirectional primer is 0.5 μL, 2×Taq PCR MasterMix II is 10 μL, and ddH2O is 8.5 μL. The primers used are 27F: AGA GTT TGA TCC TGG CCT CA and 1492R: GGT TAC CTT GTTACG ACT T.

[0039] 2) Amplification conditions: Pre-denaturation: 94℃ 5 min First denaturation: 94℃ 30 s Second annealing: 55℃ 30 s Third extension: 72℃ 2 min Cycle number: 30 cycles Fourth extension: 72℃ 10 min Fifth holding: 12℃ 10 min (6) Agarose gel electrophoresis Weigh 1.2 g of agarose into a conical flask, add 100 mL of 1xTAE, microwave intermittently for 2 min until the liquid is clear and transparent, cool slightly, add 6 μL of nucleic acid dye, shake well, no bubbles, pour into the gel plate slot, cool for 40 min after solidification, place in the electrophoresis tank, exhaust bubbles, add PCR amplification products in turn, add 3 μL of PCR amplification product to each well, run the gel at 100 V for 15 min, take out after the end and place in the gel electrophoresis imager to take pictures and save, record the number of successful PCR samples, and store the successful PCR products in a-20℃ refrigerator.

[0040] (7) Sequencing and identification The successful PCR sample was sent to Shenguo Bioengineering (Shanghai) Co., Ltd. for detection, according to the sequence results fed back, BLAST search was performed in the National Center for Biotechnology Information (NCBI) sequence database (http: / / www.ncbi.nlm.nih.gov / blast), and the strain information with the highest matching degree was selected for result recording. Through analysis and identification, the strain provided by the application is Weissella cibaria MXJSHZ8-3, and the 16S rDNA sequence thereof is shown as SEQ ID NO. 1.

[0041] Example 2: Fermentation characteristics of Weissella cibaria MXJSHZ8-3 in soy milk 1. Growth characteristics of Weissella cibaria MXJSHZ8-3 in soy milk Weissella cibaria MXJSHZ8-3 and Weissella cibaria BNCC359725 stored at-80 ℃ were inoculated in MRS medium and cultured at 25 ℃ for 24 h, and subcultured for 2-3 times, until the cell concentration reached 10 8 ~10 9 cfu / mL. The activated bacterial liquid in MRS was inoculated in soy milk at a volume ratio of 2%-5%, so that the viable cell count in the system reached 10 7 cfu / g. The inoculated sample was placed in a 25 ℃ and 37 ℃ incubator for fermentation, and the viable cell count was detected every 2 h during the fermentation process, and the results are shown in Figure 2 Figure 3 It can be seen that after 12 h of fermentation at 25 ℃, the viable cell count of strain MXJSHZ8-3 increased by 1.85 orders of magnitude, while after the same time of fermentation at 37 ℃, the viable cell count increased by only 1.672 orders of magnitude; after 12 h of fermentation at 25 ℃, the viable cell count of strain BNCC359725 increased by 1.905 orders of magnitude, while after the same time of fermentation at 37 ℃, the viable cell count increased by only 1.767 orders of magnitude, so the growth rate of the strain in soy milk fermentation at 25 ℃ was fast. ​

[0042] 2. Acid-producing characteristics of *Westernella taurizoides* MXJSHZ8-3 in soy milk The *Westernophora stolonifera* MXJSHZ8-3 and *Westernophora stolonifera* BNCC359725, stored at -80 °C, were inoculated into MRS medium and cultured at 25 °C for 24 h. The cultures were then subcultured 2-3 times until 10... 8 ~10 9 cfu / mL. Take the activated bacterial culture from the MRS and inoculate it into soy milk at a volume ratio of 2-5% to achieve a viable bacterial count of 10⁻⁶. 7 cfu / g. The inoculated samples were placed in incubators at 25 ℃ and 37 ℃ for fermentation. Samples were taken every 2 hours to detect pH changes during fermentation. The experimental results are as follows: Figure 3 As shown. By Figure 4 It can be seen that after fermentation at 25 ℃ and 37 ℃ for 12 h, the pH of strain MXJSHZ8-3 dropped below 4.7, reaching the fermentation endpoint. After fermentation at 25 ℃ for 12 h, the pH of strain MXJSHZ8-3 dropped to 4.67, while the pH of strain BNCC359725 only dropped to 4.74. Therefore, strain MXJSHZ8-3 has a faster acid production rate in low-temperature fermented soybean milk and is suitable for fermentation of soybean milk under low-temperature conditions.

[0043] 3. Determination of titratable acid value of fermented soybean milk by *Westernella esculenta* MXJSHZ8-3 The *Westernophora stolonifera* MXJSHZ8-3 and *Westernophora stolonifera* BNCC359725, stored at -80 °C, were inoculated into MRS medium and cultured at 25 °C for 24 h. The cultures were then subcultured 2-3 times until 10... 8 ~10 9 cfu / mL. Take the activated bacterial culture from the MRS and inoculate it into soy milk at a volume ratio of 2%–5% to achieve a viable bacterial count of 10⁻⁶. 7 CFU / g. The inoculated samples were placed in incubators at 25 ℃ and 37 ℃ for fermentation. Fermentation reached its endpoint after 12 h. The acidity of the fermented soy milk was determined according to the national standard GB 5009.239-2016 "Determination of Acidity in Food". The experimental results are as follows: Figure 4 As shown. By Figure 5It can be seen that the titratable acid of the fermented soy milk after 12 h fermentation of strain MXJSHZ8-3 at 25 ℃ reaches 53 TA(T°), and the titratable acid of the fermented soy milk after 12 h fermentation of strain MXJSHZ8-3 at 37 ℃ reaches only 49.3 TA(T°); the titratable acid of the fermented soy milk after 12 h fermentation of strain BNCC359725 at 25 ℃ reaches 50.3 TA(T°), and the titratable acid of the fermented soy milk after 12 h fermentation of strain BNCC359725 at 37 ℃ reaches only 47.3 TA(T°); therefore, the acid production rate of strain MXJSHZ8-3 in low-temperature fermented soy milk is faster, and it is suitable for fermentation in soy milk under low-temperature conditions.

[0044] 4. Determination of the content of volatile substances in fermented soy milk of Weissella cibaria MXJSHZ8-3 The -80 ℃-stored Weissella cibaria MXJSHZ8-3 and Weissella cibaria BNCC359725 of the application were inoculated in MRS medium and cultured at 25 ℃ for 24 h, subcultured for 2-3 times, and then inoculated in MRS medium to 10 8 ~10 9 cfu / mL. The activated bacterial liquid in MRS was inoculated in soy milk at a volume ratio of 2-5%, so that the viable bacterial count in the system reached 10 7 cfu / g. The inoculated sample was placed in a 25 ℃ and 37 ℃ incubator for fermentation, and then placed in a 4 ℃ environment for 24 h-48 h for mature fermentation.

[0045] Gas chromatography conditions and temperature program: Rtx-WAX capillary (30 m x 0.25 mm, 0.25 mm) was selected, the injection port temperature was 240 ℃, the split ratio was 10, and the carrier gas (helium) flow rate was 1 mL / min. The temperature program was set as follows: the initial temperature was 40 ℃, maintained for 10 min, increased to 140 ℃ at a rate of 5 ℃ / min, maintained for 5 min, increased to 240 ℃ at a rate of 10 ℃ / min, and maintained for 10 min.

[0046] Mass spectrometry conditions: ionization mode EI, emission energy 70 eV, emission current 200 µA, detector voltage 1.4 kV, ion source temperature 240 ℃, interface temperature 230 ℃, quadrupole temperature 150 ℃, mass scan range m / z 30-500. The spectrum obtained by GC-MS was searched and compared with the standard library of NIST 2023 standard spectrum for qualitative analysis of substances, and the peak area normalization method was used for quantitative analysis.

[0047] The content of volatile substances in fermented soy milk is shown in Table 1 and Figure 6 、 Figure 7 Table 2. Figure 6It was found that after 12 h of fermentation, the contents of fruit aroma compounds 1-(3-hydroxy-2-furanyl) ethyl ketone, myristic acid, octanol, and 1-nonanol in the fermented soy milk at 25℃ were 22.595 μg / kg, 10.852 μg / kg, 14.109 μg / kg, and 16.645 μg / kg, respectively, all significantly higher than those of *Westernella tamariscina* BNCC359725 at 25℃ and *Westernella tamariscina* MXJSHZ8-3 and *Westernella tamariscina* BNCC359725 at 37℃. Specifically, 1-(3-hydroxy-2-furanyl) ethyl ketone exhibited a caramel aroma, myristic acid a coconut aroma, octanol a citrus aroma, and 1-nonanol a rose-citrus aroma. Furthermore, from... Figure 7 It was found that, compared with unfermented soy milk, fermented soy milk had a significantly lower content of hexanal (a pungent odor), a substance associated with the beany smell of soy milk, decreasing from 265.50 μg / kg to 7.324 μg / kg. Therefore, the screened *Westernella tamariscina* MXJSHZ8-3 exhibits excellent aroma-producing properties at low temperatures and can effectively reduce beany odor substances in soy milk.

[0048] Table 1. Volatile Matter Content in Fermented Soy Milk Note: B: *Westernella sinensis* BNCC359725; M: *Westernella sinensis* MXJSHZ8-3 Weissella esculenta reduces the beany taste and enhances the flavor of soy milk during fermentation. The activated bacterial suspension of *Westernella esculenta* MXJSHZ8-3 was inoculated at a rate of 2% (v / v) into MRS medium containing sucrose, raffinose, and stachyose as the sole glycogen sources, respectively. The cultures were incubated at 25°C and 37°C for 24 hours, and the OD values ​​of the bacterial suspensions were measured. 600 Value. (By) Figure 8 It is known that *Westernella tamariscina* MXJSHZ8-3 can effectively utilize sucrose, raffinose, and stachyose for growth at 25℃. Unfermented soy milk contains small amounts of sucrose, raffinose, and stachyose. After fermentation, due to the strain's utilization of sugars during growth and reproduction, the sugars are broken down into acids, alcohols, and aldehydes / ketones. These substances impart a sour taste and complex aroma to fermented soy milk.

[0049] In the unfermented soy milk, the main volatile substances are aldehydes and furans. In the fermented soy milk by Weissella cibaria MXJSHZ8-3, the content of aldehydes is significantly reduced, while the content of alcohols, acids and ketones is significantly increased. The alcohols include octanol, 2-heptanol, iso-pentenol, cis-2-pentenol, n-hexanol, leaf alcohol, 3-octanol, 2-decene-1-alcohol, 2-ethylhexanol, trans-2-heptene-1-alcohol, trans-2-octene-1-alcohol, 1-nonanol, benzyl alcohol and phenethyl alcohol. The acids include acetic acid, propionic acid, 3-methyl valeric acid, butyric acid, hexanoic acid, octanoic acid, n-nonanoic acid, heptanoic acid, myristic acid and palmitic acid. The aldehydes include n-pentanal, n-hexanal, 2,4-dimethylbenzaldehyde, n-octanal and benzaldehyde. The ketones include 2-heptanone, 3-octanone, 1-heptene-3-ketone, methyl heptenone, 2-nonanone, 1-(3-hydroxy-2-furyl) ethanone and phenylacetone.

[0050] Generally, the beany flavor in soy milk is generated by the catalysis of linolenic acid and linoleic acid in soy milk under the joint action of lipoxygenase and oxygen during the crushing and pulping process of soy products. The main aldehyde substance is n-hexanal which produces grassy flavor and is an important off-flavor substance in soy milk. The content of n-hexanal in the fermented soy milk by Weissella cibaria MXJSHZ8-3 is significantly reduced, which greatly reduces the beany flavor. Ketones provide characteristic flavor to the fermented soy milk and are mainly produced by the oxidation, thermal degradation and microbial metabolism of unsaturated fatty acids. The ketones release significant aroma during the tasting process. The content of 3-octanone and 1-(3-hydroxy-2-furyl) ethanone in the fermented soy milk by Weissella cibaria MXJSHZ8-3 is increased. 3-octanone presents fruity flavor and 1-(3-hydroxy-2-furyl) ethanone presents caramel fruity flavor. Alcohols are produced by the oxidation of fats and the reduction of aldehydes and ketones, which produce fat flavor. The content of octanol, 2-heptanol, cis-2-pentenol, iso-pentenol and other substances in the fermented soy milk by Weissella cibaria MXJSHZ8-3 is increased. Octanol presents strong oil odor and citrus flavor, 2-heptanol presents fresh lemon flavor and fruity flavor, cis-2-pentenol and iso-pentenol present fruity flavor, 1-nonanol presents rose citrus flavor and phenethyl alcohol presents rose flower flavor. Acid substances are derived from fat hydrolysis and protein hydrolysis, which enhance aroma and help to produce sour taste. The content of butyric acid, nonanoic acid and myristic acid in the fermented soy milk by Weissella cibaria MXJSHZ8-3 is increased. Butyric acid and nonanoic acid present cheese flavor and myristic acid presents coconut flavor. Therefore, the fermentation process of soy milk by Weissella cibaria can reduce beany flavor substances and accumulate a large amount of flavor substances.

[0051] Compared with 37℃, the advantage of fermentation of soy milk by Weissella cibaria MXJSHZ8-3 at 25℃ The Weisella cibaria MXJSHZ8-3 and the Weisella cibaria BNCC359725 stored at -80 ℃ were inoculated into MRS medium and cultured at 25 ℃ for 24 h, and subcultured for 2-3 times, until the number of viable bacteria reached 10 8 ~10 9 cfu / mL. The bacterial liquid activated in MRS was inoculated into soy milk at a volume ratio of 2-5%, so that the number of viable bacteria in the system reached 10 7 cfu / g. The inoculated sample was placed in an incubator at 25 ℃ and 37 ℃ for fermentation.

[0052] Comparison was made in terms of growth characteristics, acid production characteristics, titratable acid value, and volatile flavor substances: (1) The growth rates of the Weisella cibaria MXJSHZ8-3 and the Weisella cibaria BNCC359725 in soy milk fermented at 25 ℃ were higher than those of the Weisella cibaria MXJSHZ8-3 and the Weisella cibaria BNCC359725 at 37 ℃; (2) The acid production rate of the Weisella cibaria MXJSHZ8-3 in soy milk fermented at 25 ℃ was higher than that of the Weisella cibaria MXJSHZ8-3 at 37 ℃; (3) The titratable acid value of the strain MXJSHZ8-3 in soy milk fermented at 25 ℃ was higher than those of the Weisella cibaria MXJSHZ8-3 and the Weisella cibaria BNCC359725 at 37 ℃; (4) The contents of fruit aroma substances 1-(3-hydroxy-2-furyl) ethyl ketone, myristic acid, octanol, and 1-nonanol in soy milk fermented at 25 ℃ by the strain MXJSHZ8-3 were significantly higher than those of the Weisella cibaria MXJSHZ8-3 and the Weisella cibaria BNCC359725 at 37 ℃, wherein 1-(3-hydroxy-2-furyl) ethyl ketone presents caramel fruit aroma, myristic acid presents coconut flavor, octanol presents citrus aroma, and 1-nonanol presents rose citrus odor. Therefore, compared with 37 ℃, the Weisella cibaria MXJSHZ8-3 is more suitable for fermentation in soy milk at 25 ℃, has stronger acid production characteristics in soy milk at 25 ℃, promotes the production of fruit aroma flavor substances, and improves the quality of fermented soy milk.

[0053] Example 3: Preparation of fermented soy milk by the Weisella cibaria MXJSHZ8-3 The Weisella cibaria MXJSHZ8-3 can be used to prepare fermented soy milk, and the specific preparation process is as follows: (1) Preparation of fermentation agent Weissella cibaria MXJSHZ8-3 is streaked on MRS solid medium, and cultured at 25°C for 48h to obtain single colonies; the single colonies are inoculated in MRS liquid medium, and cultured at 25°C for 24h to activate, and continuously activated for two generations to obtain an activated liquid; the activated liquid is inoculated in a culture medium at an inoculation amount of 2-5% (v / v), and cultured at 25°C for 16h to obtain a bacterial liquid; the bacterial liquid is centrifuged at 4000 rpm for 10 min to obtain a bacterial slurry; the bacterial slurry is washed once with sterile normal saline, and resuspended with sterile normal saline to obtain a starter.

[0054] (2) Preparation of fermented soy milk 50-200 g of dry soybeans are weighed and soaked overnight, the soaked soybeans are peeled, water is added at a ratio of 1:5-10 by mass of the dry soybeans, the soy milk machine is operated in the thick soy milk mode for pulping, the colloid mill is operated for 5 min, and the pulping product is filtered through a 150-200 mesh filter screen after cooling, sterilized at 115°C for 15 min, and then cooled to 15-35°C, 2-5% of the Weissella cibaria MXJSHZ8-3 starter is added, the inoculated sample is placed in a 25°C incubator for fermentation for 10-12h, and then placed in a 4°C environment for mature fermentation for 24-48h.

[0055] Example 4: Preparation of fermented fruit and vegetable juice beverage by Weissella cibaria MXJSHZ8-3 The Weissella cibaria MXJSHZ8-3 can be used to prepare a fruit and vegetable juice beverage, and the specific preparation process of the fruit and vegetable juice beverage is as follows: (1) Preparation of starter Weissella cibaria MXJSHZ8-3 is streaked on MRS solid medium, and cultured at 25°C for 48h to obtain single colonies; the single colonies are inoculated in MRS liquid medium, and cultured at 25°C for 24h to activate, and continuously activated for two generations to obtain an activated liquid; the activated liquid is inoculated in a culture medium at an inoculation amount of 2-5% (v / v), and cultured at 25°C for 16h to obtain a bacterial liquid; the bacterial liquid is centrifuged at 4000 rpm for 10 min to obtain a bacterial slurry; the bacterial slurry is washed once with sterile normal saline, and resuspended with sterile normal saline to obtain a starter.

[0056] (2) Preparation of fermented fruit and vegetable juice Fresh fruits and vegetables are washed and juiced to obtain fruit and vegetable juice; the fruit and vegetable juice is high-temperature heat-killed at a temperature of 140°C for 2 seconds to obtain sterilized fruit and vegetable juice; the sterilized fruit and vegetable juice is cooled to room temperature, and the Weissella cibaria MXJSHZ8-3 starter is added to the sterilized fruit and vegetable juice to a concentration of not less than 1×10 7 CFU / mL to obtain a fruit and vegetable beverage, which needs to be stored in a cold storage at 4°C.

[0057] Example 5: Preparation of fermented milk by Weissella cibaria MXJSHZ8-3 Weissella cibaria MXJSHZ8-3 can be used to prepare fermented milk, and the specific preparation process of fermented milk is as follows: Preparation of starter culture Weissella cibaria MXJSHZ8-3 was streaked on MRS solid medium and cultured at 25°C for 48h to obtain single colonies; the single colonies were inoculated in MRS liquid medium and cultured at 25°C for 24h for activation, and the activated liquid was obtained after continuous activation for two generations; the activated liquid was inoculated in the culture medium at an inoculation amount of 2-5% (v / v) and cultured at 25°C for 16h to obtain the bacterial liquid; the bacterial liquid was centrifuged at 4000 rpm for 10 min to obtain the bacterial slurry; the bacterial slurry was washed once with sterile normal saline and resuspended with sterile normal saline to obtain the starter culture.

[0058] (2) Preparation of fermented milk The milk was heated at 85°C for 30 min, cooled to room temperature, and then 2-5% Weissella cibaria MXJSHZ8-3 was added, and the mixture was fermented at 25°C for 12h. The fermentation endpoint was when the pH was 4.50-4.70. After fermentation, the yogurt was cooled to 4°C and stored for 24h to obtain the final product.

[0059] Example 6: Preparation of fermented pickles by Weissella cibaria MXJSHZ8-3 Weissella cibaria MXJSHZ8-3 can be used to prepare fermented pickles, and the specific preparation process of fermented pickles is as follows: Preparation of starter culture Weissella cibaria MXJSHZ8-3 was streaked on MRS solid medium and cultured at 25°C for 48h to obtain single colonies; the single colonies were inoculated in MRS liquid medium and cultured at 25°C for 24h for activation, and the activated liquid was obtained after continuous activation for two generations; the activated liquid was inoculated in the culture medium at an inoculation amount of 2-5% (v / v) and cultured at 25°C for 16h to obtain the bacterial liquid; the bacterial liquid was centrifuged at 4000 rpm for 10 min to obtain the bacterial slurry; the bacterial slurry was washed once with sterile normal saline and resuspended with sterile normal saline to obtain the starter culture.

[0060] (2) Preparation of fermented pickles The fresh vegetables were washed and blanched in water at 60°C for 5 min to inactivate endogenous enzymes and reduce microbial load. After cooling, 2-5% Weissella cibaria MXJSHZ8-3 was added, and sufficient boiled and cooled 6% (w / v) saline was added until the vegetables were completely submerged. After fermentation, the sealed cowpea pickle sample was stored at room temperature (25 ± 2°C).

[0061] Although the present application has been disclosed in its preferred embodiments with reference to the accompanying drawings, it is not intended to limit the present application thereto, and various modifications and alterations can be made thereto by those skilled in the art without departing from the spirit and scope of the present application, and the scope of protection of the present application should be defined by the appended claims.

Claims

1. A strain of *Weissella cibaria*, characterized in that, The *Westernella esculenta* MXJSHZ8-3 was deposited on July 14, 2025, at the Guangdong Provincial Center for Microbial Culture Collection, with accession number GDMCC 66672, located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

2. A starter culture containing the *Westernella esculenta* MXJSHZ8-3 as described in claim 1.

3. The fermenting agent according to claim 2, characterized in that, The fermenting agent is a direct-inoculation fermenting agent, and the specific preparation method is as follows: *Westernella esculenta* MXJSHZ8-3 is activated and cultured until the viable cell concentration reaches 10⁻⁶. 8 CFU / mL or higher, then centrifuged, washed with buffer, and added lyophilization protectant to adjust the viable cell concentration to 10⁻⁶. 9 The concentration of cfu / mL or higher is subjected to vacuum freeze-drying, and the freeze-dried product is the direct-inoculation starter.

4. The use of the *Westernella esculenta* MXJSHZ8-3 as described in claim 1 or the starter culture as described in claim 2 or 3 in fermented foods.

5. The application according to claim 4, characterized in that, The fermented foods include fermented fruit and vegetable juices, fermented milk, fermented kimchi, or fermented soy milk.

6. The application according to claim 5, characterized in that, The fermented soy milk includes yogurt soy milk and fermented soy milk beverages.

7. The application according to claim 4, characterized in that, Fermented foods produced using *Westernella tamariscina* MXJSHZ8-3 or fermentation agents containing *Westernella tamariscina* MXJSHZ8-3 have one or more flavor compounds among alcohols, acids, aldehydes, phenols, or furans.

8. The application according to claim 7, characterized in that, The alcohols include octanol, 2-heptanol, isopentenol, cis-2-pentenol, n-hexanol, leaf alcohol, 3-octanol, 2-decen-1-ol, 2-ethylhexanol, trans-2-hepen-1-ol, trans-2-octen-1-ol, 1-nonanol, benzyl alcohol, or phenethyl alcohol; the acids include acetic acid, propionic acid, 3-methylvaleric acid, butyric acid, hexanoic acid, octanoic acid, n-nonanoic acid, heptanoic acid, myristic acid, or palmitic acid; the aldehydes include n-pentanol, n-hexanol, 2,4-dimethylbenzaldehyde, n-octanol, benzaldehyde; the ketones include 2-heptanone, 3-octanone, 1-hepten-3-one, methylheptenone, 2-nonanone, 1-(3-hydroxy-2-furanyl)ethyl ketone, or acetophenone; the phenols include methyl maltol; and the furans include 2-pentylfuran.

9. The application according to claim 6, characterized in that, The fermentation temperature for fermented soy milk is 25℃.

10. The application according to claim 6, characterized in that, The preparation method of fermented soy milk is as follows: Weigh 50-200g of dry soybeans, soak them in water overnight, remove the skins from the soaked soybeans, add water at a ratio of 1:5-10 (by weight of the soybeans), blend in a soy milk maker using the thick soy milk setting, grind in a colloid mill for 5 minutes, cool, filter through a 150-200 mesh filter, sterilize at 115℃ for 15 minutes, and cool to 15℃-35℃; add 2%-5% of starter culture or 10% of fermentation agent. 8 ~10 9 CFU / mL Weissella esculenta MXJSHZ8-3 was fermented at 25°C for 10-12 hours, and then placed at 4°C for 24-48 hours for maturation fermentation.

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