Lactobacillus plantarum h3-1 with cholesterol-lowering function and application thereof

Abstract

The application discloses a plant lactobacillus H3-1 with a cholesterol-lowering function and application thereof. The plant lactobacillus H3-1 has a preservation number of CGMCC No. 38948, and a strain genome NCBI number of SRR38400353. The application has excellent gastrointestinal tolerance (a survival rate of more than 68% after being treated by a pH 3.0 simulated gastric juice for 3 hours), high BSH enzyme activity (about 0.424 U / mg) and significant in-vitro cholesterol-lowering capacity. More importantly, the fermented milk obtained by single-bacterium fermentation of the strain has a coordinated taste feature of a suitable sour taste value, a significantly lower bitter taste value (a decrease of 83.4% after being stored for 7 days) than a commercial control group, and a significantly higher umami taste value and richness value than the commercial control group. The single-bacterium fermented milk of the strain also has good hardness and viscosity, and can form a stable gel network. The strain has good broad-spectrum applicability to various characteristic milk sources such as cow milk, sheep milk, horse milk, camel milk and donkey milk, and can be used for preparing functional fermented foods with a cholesterol-lowering function and excellent flavor.

Description

Technical Field

[0001] This invention relates to the fields of microbial technology and food engineering, specifically to a strain of Lactiplantibacillus plantarum H3-1 with high bile salt hydrolase activity and in vitro cholesterol-lowering ability, and capable of producing excellent and harmonious flavor, and its application in functional fermented foods. Background Technology

[0002] Hypercholesterolemia is one of the most important controllable risk factors for cardiovascular disease. In recent years, consuming functional fermented foods with cholesterol-lowering properties through daily diet has become an important means of assisting in the regulation of blood lipids. Probiotics mainly hydrolyze conjugated bile acids into free bile acids through the bile salt hydrolase (BSH) pathway, thereby promoting the conversion and excretion of cholesterol into bile acids, achieving the physiological effect of reducing serum total cholesterol and low-density lipoprotein cholesterol.

[0003] Lactiplantibacillus plantarum is a widely used food-grade probiotic. Its cholesterol-lowering ability has significant strain specificity. Therefore, screening new strains with high BSH activity and excellent cholesterol-lowering ability from natural sources has important industrial value.

[0004] However, many functional fermented foods with clear health claims (especially probiotic fermented milk) often suffer from poor flavor due to the metabolic characteristics of the strains used. These defects are mainly manifested in the following ways: (1) excessive acid production, resulting in an abrupt and irritating sour taste; (2) the production of bitter amino acids or bitter peptides, leading to an unpleasant bitter taste; and (3) a lack of flavor compounds, resulting in a weak and monotonous overall flavor. These flavor defects have become key obstacles to the acceptance and commercialization of probiotic fermented foods by consumers.

[0005] Therefore, developing a single strain that simultaneously possesses clear health functions (such as cholesterol reduction) and excellent flavor-producing ability is a core technological requirement for improving the quality of functional fermented foods. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a plant lactobacillus H3-1 with cholesterol-lowering function and its application.

[0007] To achieve the aforementioned objective, the technical solution of the present invention is implemented as follows: A strain of *Lactiplantibacillus plantarum* H3-1, taxonomically named *Lactiplantibacillus plantarum*, with accession number CGMCC No. 38948, was deposited at the China General Microbiological Culture Collection Center on June 1, 2026, and its genome number is SRR38400353 (NCBI).

[0008] The *Lactobacillus plantarum* H3-1 of this invention has the following biological characteristics: the colonies are milky white, smooth, and have regular edges; the cells are Gram-positive, short rod-shaped, and arranged in pairs or short chains; catalase-negative, non-motile, and non-spore-forming; the optimal growth temperature is 37℃, and the optimal growth pH is 6.0-6.5.

[0009] The *Lactobacillus plantarum* H3-1 of this invention has the following functional characteristics: (1) After treatment in simulated gastric juice at pH 3.0 for 3 h, the survival rate reached about 68%; (2) After treatment in an environment containing 0.3%-1.0% bile salts for 6 h, the bacteria can continue to proliferate, showing excellent bile salt tolerance; (3) The cell surface hydrophobicity is about 28.4%, and the self-aggregation is about 45.8%, showing good potential for intestinal adhesion and colonization; (4) The BSH enzyme activity is as high as about 0.424 U / mg, showing efficient bile acid hydrolysis ability; (5) In a culture medium containing exogenous cholesterol, the cholesterol degradation of the live bacteria group reached about 47.77 mg / L, and the cholesterol adsorption / degradation of the heat-killed bacteria group reached about 48.46 mg / L, showing strong cholesterol-lowering potential; (6) The fermented milk of *Lactobacillus plantarum* H3-1 single strain has a harmonious taste characteristic of moderate acidity, low bitterness, and high umami and richness values, as objectively analyzed by electronic tongue, which can significantly improve the basic flavor of fermented milk.

[0010] The second objective of this invention is to provide the application of *Lactobacillus plantarum* H3-1 in the preparation of functional fermented foods with excellent flavor. These functional fermented foods include, but are not limited to, fermented milk, flavored yogurt, probiotic beverages, probiotic solid beverages, probiotic freeze-dried powder, probiotic capsules, and probiotic tablets. These functional fermented foods have cholesterol-lowering and / or flavor-improving functions.

[0011] A third objective of this invention is to provide a fermentation agent composition containing *Lactobacillus plantarum* H3-1; preferably, the fermentation agent composition further contains a commercial fermentation agent; the fermentation agent composition is suitable for fermenting one or more dairy raw materials selected from cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk.

[0012] The fourth objective of this invention is to provide a fermented milk, which is obtained by fermentation of Lactobacillus plantarum H3-1 alone or by fermentation of a starter culture composition; the raw milk for the fermented milk is selected from one or more of cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk.

[0013] The present invention, Lactobacillus plantarum H3-1 and its related technical solutions, has the following beneficial effects: Lactobacillus plantarum H3-1 exhibits significant gastrointestinal tolerance, high BSH activity, and excellent in vitro cholesterol-lowering ability; both live and heat-killed bacteria can produce cholesterol-lowering effects. Objective analysis of Lactobacillus plantarum H3-1 single-strain fermented milk using an electronic tongue system showed that: during storage at 4℃, the bitterness value was significantly lower than that of the commercial control group (the decrease could reach 40%-80% after 7-28 days of storage), while the umami and richness values ​​were significantly higher than those of the commercial control group (the absolute values ​​were closer to zero or showed a positive shift). The acidity value was within a suitable range and was significantly lower than that of the commercial control group in the later stages of storage. The overall taste profile was more balanced and harmonious, which can significantly improve the inherent defects of probiotic fermented milk, such as single flavor, excessive acidity, and bitterness. Lactobacillus plantarum H3-1 single-strain fermented milk can form a stable gel network, with good basic textural properties such as hardness and viscosity, as well as suitable microrheological properties, and the product has a good commercial form. Lactobacillus plantarum H3-1 (used in combination with commercial starter cultures or alone) exhibits good broad-spectrum applicability to various specialty milk sources such as cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk. Within 21 days of storage, the number of viable bacteria remains stable at a high level, and the pH and titratable acidity change slowly. The resulting products have good curd state and harmonious flavor, which can significantly improve the commercial quality and added value of fermented products from specialty milk sources.

[0014] The beneficial effects of this invention are reflected in: (1) The *Lactobacillus plantarum* H3-1 provided by this invention has excellent gastrointestinal tolerance: the survival rate after treatment in simulated gastric juice at pH 3.0 for 3 h is 68.59%, which is significantly higher than that of control strains H5-3 (44.81%) and H5-8 (55.93%); after treatment in an environment containing 0.3%-1.0% bile salts for 6 h, the bacteria can still continue to proliferate, with a proliferation rate of 133.1%-165.7%, indicating that the strain can effectively tolerate gastric acid and bile salt stress in the human digestive tract, successfully reach the intestine and exert its probiotic function.

[0015] (2) The *Lactobacillus plantarum* H3-1 provided by this invention has high BSH enzyme activity and excellent in vitro cholesterol-lowering ability. Its BSH enzyme activity reached 0.424±0.024 U / mg protein, which was significantly higher than that of the control strains H3-2 (0.387±0.020 U / mg) and H3-12 (0.402±0.009 U / mg); the cholesterol degradation of the live bacteria group reached 47.77±2.83 mg / L, and the cholesterol adsorption / degradation of the heat-killed bacteria group reached 48.46±3.50 mg / L, both of which were significantly higher than those of the control strains. More importantly, both live and heat-killed bacteria can produce significant cholesterol-lowering effects, indicating that this strain can effectively exert its cholesterol-lowering function whether applied in live or inactivated form (post-biotic form), greatly expanding its application flexibility in different product forms.

[0016] (3) The *Lactobacillus plantarum* H3-1 single-strain fermented milk provided by this invention has significantly improved taste quality. Objective analysis by the electronic tongue system showed that during the storage period at 4℃, the bitterness value of the H3-1 single-strain fermented milk was significantly lower than that of the commercial control group: on the 7th day of storage, the bitterness value of the H3-1 group (1.18) was 83.4% lower than that of the commercial control group (7.10), and on the 28th day of storage, the bitterness value of the H3-1 group (7.31) was 40.8% lower than that of the commercial control group (12.34); in terms of umami value, the H3-1 group (-5.75) on the 28th day of storage was much higher than that of the commercial control group (-17.46), and the richness value of the H3-1 group (-7.27) was also significantly better than that of the commercial control group (-17.22); the acidity value was within the appropriate range (37.96-39.05) during the storage period of 1-14 days, and was significantly lower than that of the commercial control group on the 7th and 14th days of storage. Based on the above taste indicators, H3-1 single-strain fermented milk has a more balanced and harmonious overall taste profile, which can significantly improve the inherent defects of probiotic fermented milk such as single flavor, excessive sourness, and bitterness, and greatly improve the consumer acceptance of the product.

[0017] (4) The *Lactobacillus plantarum* H3-1 single-strain fermented milk provided by this invention has good textural properties and commercial form. Its hardness (44.18 g) and viscosity (1985 cP) are significantly better than those of the commercial control group (41.99 g, 1440 cP), and the macroscopic viscosity index (MVI) reaches 1.18 (commercial control group is 0.92), indicating that the single-strain fermentation can form a stable gel network structure, the product has good curd state and fine texture, and can be used independently for the industrial production of functional flavored fermented milk without relying on commercial starter cultures, reducing production costs and formula complexity.

[0018] (5) The *Lactobacillus plantarum* H3-1 provided by this invention exhibits good broad-spectrum applicability to various specialty milk sources, including cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk. In each milk source, the viable count remained above 8.44-8.85 lgCFU / mL during 21 days of storage, the pH steadily decreased without drastic post-acidification (pH ≥ 4.23 at 21 days), and the titratable acidity changed gradually, not exceeding 115°T. The fermented milk from each milk source showed good coagulation, uniform and dense texture, and no significant whey separation. The goat's milk fermentation milk exhibited a significantly reduced muttony odor, the mare's milk fermentation milk had a refreshing taste, the camel's milk fermentation milk had a mellow and harmonious flavor, and the donkey's milk fermentation milk had a soft and mild texture. This broad-spectrum adaptability significantly enhances the added value of specialty milk sources and provides high-quality microbial resources for the diversified development of specialty milk source fermentation products.

[0019] In summary, the *Lactobacillus plantarum* H3-1 provided by this invention is a novel strain that combines high probiotic efficacy (strong cholesterol-lowering ability) with excellent sensory qualities (harmonious flavor and excellent texture). It also has broad-spectrum adaptability to dairy sources and has extremely high industrial application value and market prospects. Attached Figure Description

[0020] In the attached diagram: Figure 1 A complete genome map of Lactobacillus plantarum H3-1; Figure 2 A bar chart comparing the survival rates of Lactobacillus plantarum H3-1 and the control strain under simulated gastric juice conditions at pH 3.0 and 10 g / L bile salts. Figure 3 A bar chart comparing the BSH enzyme activity and in vitro cholesterol-lowering ability (live group and lethal group) of Lactobacillus plantarum H3-1 and control strains. Figure 4 Radar graphs showing the profiles of the six tastes (sour, bitter, astringent, umami, richness, and aftertaste) on the electronic tongue during the storage period of fermented milk from the commercial control group and the H3-1 single-strain group; Figure 5 Bar chart showing the changes in bitterness and umami value of fermented milk from the commercial control group and the H3-1 single-strain group during the storage period; Figure 6 The images show actual photos of fermented milk products obtained by fermenting cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk with the fermenting agent described in this invention. They demonstrate that the coagulated milk from each milk source is in good condition, has a fine texture, and exhibits no severe whey separation. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the invention, and not all of them. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] The commercial fermentation agent YF-L904 used in this invention was purchased from Chr. Hansen; MRS liquid culture medium and agar were purchased from Beijing Luqiao Technology Co., Ltd.; bile salts (bovine bile salts), cholesterol standards, o-phthalaldehyde (OPA), sodium taurodeoxycholate (TDCA) and other reagents were purchased from Sigma-Aldrich; the electronic tongue system used was the SA402B model from Insent Corporation, Japan; fresh cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk were purchased from quality-assured pastures in Inner Mongolia.

[0023] Example 1: Isolation, identification and preservation of Lactobacillus plantarum H3-1 1.1 Strains Isolation: Traditional fermented milk samples collected from Inner Mongolia were anaerobically cultured on MRS agar at 37°C for 48 h using a serial dilution method. Single colonies with typical morphology were selected and purified for three generations. The activated and frozen strains were preserved and numbered H3-1.

[0024] 1.2 Morphological identification: Colonies are milky white, round, smooth, with regular edges, and opaque; Gram-positive, short rod-shaped, arranged in pairs or short chains; catalase-negative, non-spore-forming, non-flagellated, and non-motile.

[0025] 1.3 Molecular biological identification: Genomic DNA was extracted using the CTAB method. The 16S rRNA gene was amplified by PCR using the 27F / 1492R universal primers and bidirectionally sequenced. The sequencing results were compared with the GenBank database by BLAST. The results showed that the similarity with the type strain of Lactiplantibacillus plantarum was more than 99.9%. Further sequencing of recA, pheS, and tuf housekeeping genes and whole-genome ANI analysis confirmed that the strain was Lactiplantibacillus plantarum H3-1.

[0026] 1.4 Preservation of strain: The *Lactobacillus plantarum* H3-1 described in this invention has been preserved, with accession number CGMCCNo.38948 and NCBI genome number SRR38400353.

[0027] Example 2 Characterization of the core probiotic functions of Lactobacillus plantarum H3-1 To evaluate the probiotic potential of *Lactobacillus plantarum* H3-1, it was compared in parallel with two other *Lactobacillus plantarum* strains (H5-3 and H5-8) isolated from conventional fermented milk during the same period; H3-2 and H3-12 were used as control strains in the BSH enzyme activity and cholesterol-lowering assays. All strains were kept consistent in activation conditions and detection methods, with three replicates per group.

[0028] 2.1 Simulated gastric juice tolerance: The activated bacterial solution was centrifuged to collect the bacterial cells and resuspended to the same OD600. The cells were then inoculated into simulated gastric juice containing 3 mg / mL pepsin at pH 3.0 and incubated at 37°C for 3 h. The results are shown in Table 1.

[0029] Table 1. Changes in viable bacterial counts of each strain in simulated gastric fluid at pH 3.0 (×10^9 CFU / mL, n=3) As shown in Table 1, the survival rate of Lactobacillus plantarum H3-1 after treatment in artificial gastric fluid at pH 3.0 for 3 h was 68.59%, which was significantly higher than that of the tested control strains H5-3 (44.81%) and H5-8 (55.93%) (P<0.05).

[0030] 2.2 Bile salt tolerance: The activated bacterial solution was inoculated at 10% (v / v) into MRS liquid medium containing 0.3%, 0.5% and 1.0% bovine bile salts, and incubated at 37°C for 0 h and 6 h. The number of viable bacteria was counted on pour plates. The results are shown in Table 2.

[0031] Table 2. Changes in viable bacterial counts of H3-1 in different concentrations of bile salts (×10^9 CFU / mL, n=3) As shown in Table 2, the *Lactobacillus plantarum* H3-1 strain continued to proliferate after being treated with 0.3%-1.0% bile salt stress for 6 h, with a proliferation rate of 133.1%-165.7%, indicating that the strain has excellent bile salt tolerance and can tolerate the intestinal environment under the physiological bile salt concentration of the human small intestine.

[0032] 2.3 Cell surface hydrophobicity and self-aggregation: The results showed that the cell surface hydrophobicity of Lactobacillus plantarum H3-1 was about 28.4% and the self-aggregation was about 45.8%, indicating that this strain has good potential for intestinal adhesion and colonization.

[0033] 2.4 BSH enzyme activity assay: Using TDCA as substrate, the amount of released amino acids was determined by ninhydrin colorimetric method after reacting at 37℃ for 30 min. The results are shown in Table 3.

[0034] Table 3. BSH enzyme activity of each strain (U / mg protein, n=3) As shown in Table 3, the BSH enzyme activity of *Lactobacillus plantarum* H3-1 reached 0.424±0.024 U / mg protein, which was significantly higher than that of control strains H3-2 (0.387±0.020 U / mg) and H3-12 (0.402±0.009 U / mg), indicating that it has a strong bile acid deconjugation ability.

[0035] 2.5 In vitro cholesterol-lowering ability: MRS liquid culture medium containing 0.1 mg / mL water-soluble cholesterol was prepared, and live bacteria (live bacteria group) or bacteria inactivated at 80℃ for 30 min (lethal group) were inoculated. After static incubation at 37℃ for 24 h, the residual cholesterol concentration was determined by the o-phthalaldehyde method. The results are shown in Table 4.

[0036] Table 4. In vitro cholesterol-lowering ability of each strain (mg / L, n=3) As shown in Table 4, the in vitro cholesterol degradation of the live Lactobacillus plantarum H3-1 group reached 47.77±2.83 mg / L, while that of the heat-killed group was still 48.46±3.50 mg / L, both significantly higher than those of the control strains H3-2 (live group 25.12±0.40 mg / L, lethal group 28.09±0.49 mg / L) and H3-12 (live group 11.87±1.13 mg / L, lethal group 32.04±1.36 mg / L). This indicates that this strain can exert a significant cholesterol-lowering effect regardless of whether it is applied in live or inactivated form.

[0037] Example 3: Electronic tongue flavor evaluation of fermented milk by Lactobacillus plantarum H3-1 single strain 3.1 Preparation of Fermented Milk: Fresh milk was heated to 55-60℃, and 7% (w / w) white sugar was added and stirred until completely dissolved; preheated to 65℃ and homogenized under high pressure at 20 MPa; sterilized at 95℃ for 5 min and then cooled to 42℃. The milk was inoculated into groups as follows: ① Commercial control group: inoculated with only 0.004‰ (w / w) of commercial starter culture YF-L904; ② H3-1 single-strain group: inoculated with only 1.0% (v / v) of *Lactobacillus plantarum* H3-1 liquid starter culture (viable count ≥1×10^9 CFU / mL). Fermentation was carried out at 42℃ until pH 4.5-4.6, then cooled to below 10℃ and post-ripened at 4℃ for 12 h before being dispensed for use.

[0038] 3.2 Electronic tongue detection method: The SA402B electronic tongue system of Insent Corporation, Japan was used. This system is equipped with multiple taste sensors, including sour taste (CA0), bitter taste (CO0), astringent taste (AE1), umami taste (AAE), and richness (CT0). Samples were taken on the 1st, 7th, 14th, 21st and 28th days of storage. After centrifugation to remove curd, the supernatant was taken for testing. All data were characterized by relative intensity values, and each group was in triplicate.

[0039] 3.3 Results and Analysis: The key taste indicators of each group during the storage period are shown in Table 5.

[0040] Table 5. Changes in key taste indicators of electronic tongue during the storage period of fermented milk in each group (n=3) As shown by the electronic tongue data in Table 5, the fermented milk from the *Lactobacillus plantarum* H3-1 single-strain group has the following advantages compared to the commercial control group: (1) Sourness: The sourness value of group H3-1 (37.96-39.05) was within the appropriate range during storage from 1 to 14 days, and was significantly lower than that of the commercial control group (40.75 and 39.63) during storage at 7 and 14 days, proving that it did not have the defect of excessive acid production and the corresponding taste was more mellow; (2) Bitterness: The bitterness value of the H3-1 group at each time point was significantly lower than that of the commercial control group. In particular, on the 7th day of storage, the bitterness value of the H3-1 group was only 1.18, which was 83.4% lower than that of the commercial control group (7.10); on the 14th day of storage, the bitterness value of the H3-1 group (4.81) was 15.9% lower than that of the commercial control group (5.72); on the 21st and 28th days of storage, the bitterness value of the H3-1 group was still significantly lower than that of the commercial control group (day 28: 7.31 vs 12.34, a decrease of 40.8%), which proves that this strain does not produce unpleasant bitterness; (3) Umami and richness: The umami and richness values ​​of the H3-1 group were higher than those of the commercial control group throughout the entire storage process (the absolute values ​​were closer to zero or positively offset). In particular, the umami value (-5.75) was much higher than that of the commercial control group (-17.46) and the richness value (-7.27) was much higher than that of the commercial control group (-17.22) after 28 days of storage, indicating that the fermented milk of the H3-1 group has more prominent umami and richness of aftertaste. (4) Taste radar chart: Based on the above data, the taste profile (sourness, bitterness, umami, richness, etc.) of the fermented milk in group H3-1 was significantly more balanced and harmonious than that of the commercial control group (see appendix for details). Figure 4 and attached Figure 5The above electronic tongue data objectively demonstrates that the single-strain fermentation of *Lactobacillus plantarum* H3-1 can effectively regulate the fermentation metabolic pathway, producing a harmonious flavor with moderate acidity, low bitterness, and prominent umami and richness, overcoming the inherent defects of traditional probiotic fermented milk, such as single flavor, excessive acidity, and unpleasant bitterness.

[0041] Example 4: Basic texture and microrheological properties of fermented milk from a single strain of Lactobacillus plantarum H3-1 4.1 Experimental Methods: The fermented milk samples were prepared in the same manner as in Example 3. After ripening, hardness and viscosity were measured using a texture analyzer (TA.XTPlus) equipped with an A / BE probe, and the macroscopic viscosity index (MVI) was measured using a microrheometer (Rheolaser Master, Formulaction). Each group was tested in triplicate, and measurements were taken 12 hours after ripening.

[0042] 4.2 The results are shown in Table 6.

[0043] Table 6. Basic texture and microrheological properties of H3-1 single-strain fermented milk and control group (n=3) As shown in Table 6, the hardness (44.18 g) and viscosity (1985 cP) of the single-strain fermented milk of *Lactobacillus plantarum* H3-1 were significantly better than those of the commercial control group (41.99 g, 1440 cP). The macroscopic viscosity index (MVI) reached 1.18 (compared to 0.92 for the commercial control group), indicating that the single-strain fermentation of this strain can form a stable gel network structure and the product has a good commercial form. It can be used independently for the industrial production of functional flavored fermented milk without relying on commercial starter cultures.

[0044] Example 5: Applicability of Lactobacillus plantarum H3-1 in various specialty milk sources 5.1 Fermentation process: Fresh goat milk, mare milk, camel milk, and donkey milk were used as raw materials. The raw materials were heated, homogenized, sterilized (95℃, 5 min), and cooled to 42℃ according to the process in Example 3. The raw materials were inoculated as follows: commercial starter YF-L904 0.004‰ (w / w) combined with Lactobacillus plantarum H3-1 liquid starter 1.0% (v / v). The fermentation was carried out at a constant temperature of 42℃ until the pH reached 4.5-4.6, then cooled and stored at 4℃.

[0045] 5.2 Product Appearance and Flavor Observation: All fermented milk products from various sources exhibited good curdling properties, uniform and dense texture, smooth surface, and no obvious whey separation. Goat milk fermented milk possessed a typical fermented milk flavor with significantly reduced goaty odor and a delicate texture; mare milk fermented milk had a refreshing taste and rich flavor; camel milk fermented milk formed a stable system, with a rich flavor and a harmonious balance of salty and savory notes; donkey milk fermented milk had a soft texture and a mild, refreshing flavor. See attached photos of the actual products from each milk source. Figure 6 .

[0046] 5.3 Physicochemical indicators during storage: Samples were taken on days 0, 7, 14 and 21 to determine the viable count (1g CFU / mL), pH and titratable acidity (°T) of fermented milk from each milk source. Each group was in triplicate. The results are shown in Tables 7-9.

[0047] Table 7. Changes in viable bacteria count during storage of fermented milk from different dairy sources (lg CFU / mL, n=3) Table 8. pH changes during storage of fermented milk from different dairy sources (n=3) Table 9. Changes in titratable acidity of fermented milk from different dairy sources during storage (°T, n=3) As shown in Tables 7-9, the *Lactobacillus plantarum* H3-1 strain described in this invention exhibits excellent fermentation performance and storage stability in four types of specialty milk sources: goat milk, mare milk, camel milk, and donkey milk. Within 21 days of storage, the viable cell count remained consistently above 8.44-8.85 lg CFU / mL; the pH steadily decreased without significant post-acidification (pH ≥ 4.23 at 21 days); and the titratable acidity showed a gradual change with a reasonable overall trend, not exceeding 115°T. Based on the above indicators and observations of appearance and flavor, it is evident that the strain described in this invention has good broad-spectrum adaptability to various specialty milk protein systems, overcoming the inherent defects of weak coagulation ability, easy whey separation, and poor flavor harmony in specialty milk sources. The resulting fermented milk products from specialty milk sources exhibit good coagulation state, harmonious flavor, and stable storage.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A *Lactiplantibacillus plantarum* H3-1, characterized in that, The preservation number of the *Lactobacillus plantarum* H3-1 is CGMCC No. 38948.

2. The *Lactobacillus plantarum* H3-1 according to claim 1, characterized in that, The *Lactobacillus plantarum* H3-1 possesses one or more of the following characteristics: (a) Survival rate ≥68% after treatment in simulated gastric fluid at pH 3.0 for 3 h; (b) They can continue to proliferate after being treated in an environment containing 0.3%-1.0% bile salts for 6 h; (c) The cell surface hydrophobicity was 28.4% ± 5%, and the self-aggregation was 45.8% ± 5%; (d) Bile salt hydrolase activity ≥ 0.400 U / mg protein; (e) In a culture medium containing exogenous cholesterol, the cholesterol degradation of the live bacteria group was ≥45 mg / L, and the cholesterol adsorption / degradation of the heat-killed bacteria group was ≥45 mg / L.

3. The use of *Lactobacillus plantarum* H3-1 as described in claim 1 or 2 in the preparation of products with cholesterol-lowering and / or flavor-improving functions, characterized in that... The product is selected from one or more of the following: fermented milk, yogurt, flavored yogurt, probiotic beverages, probiotic solid beverages, probiotic freeze-dried powder, probiotic capsules, and probiotic tablets.

4. A fermentation agent composition, characterized in that, The fermentation agent composition contains *Lactobacillus plantarum* H3-1 as described in claim 1 or 2; optionally, the fermentation agent composition further contains a commercial fermentation agent; the fermentation agent composition is suitable for fermenting one or more dairy raw materials selected from cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk.

5. The fermentation agent composition according to claim 4, characterized in that, The commercial fermentation agent is YF-L904; the inoculum amount of the commercial fermentation agent is 0.002‰-0.01‰ (w / w), and the inoculum amount of *Lactobacillus plantarum* H3-1 is 0.5%-2.0% (v / v).

6. A fermented milk, characterized in that, The fermented milk is prepared by fermentation of Lactobacillus plantarum H3-1 as described in claim 1 or 2 alone, or by fermentation of the starter culture composition as described in claim 4 or 5; the raw milk for the fermented milk is selected from one or more of cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk.

7. The fermented milk according to claim 6, characterized in that, When the fermented milk is detected using an electronic tongue system, compared to the control fermented milk using a commercial starter culture, it exhibits one or more of the following taste characteristics during the storage period: (a) Bitterness value decreased; (b) Increased umami value; (c) The richness value increased; (d) The acidity value is within a suitable range.

8. A method for preparing flavor-enhanced fermented milk, characterized in that, The method includes the steps of inoculating a milk raw material with *Lactobacillus plantarum* H3-1 as described in claim 1 or 2 and fermenting it; the milk raw material is selected from one or more of cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk; preferably, the fermentation temperature is 40-43℃; and the fermentation endpoint is pH 4.5-4.

6.

9. The method according to claim 8, characterized in that, The inoculum amount of *Lactobacillus plantarum* H3-1 is 0.5%-2.0% (v / v); optionally, the method further includes simultaneously inoculating 0.002‰-0.01‰ (w / w) of commercial starter culture YF-L904; the method further includes a step of post-fermentation at 0-6℃ for 8-15 h after fermentation.

10. The use of *Lactobacillus plantarum* H3-1 according to claim 1 or 2 in the preparation of fermented milk having one or more of the following characteristics, wherein the raw milk for fermented milk is selected from one or more of cow's milk, goat's milk, mare's milk, camel's milk, and donkey's milk: (a) The electronic tongue bitterness value of the fermented milk was lower than that of the commercial control group; (b) The electronic tongue umami value or richness value of the fermented milk was higher than that of the commercial control group; (c) The hardness of the fermented milk is ≥40 g and the viscosity is ≥1500 cP; (d) The number of viable bacteria in fermented milk maintained above 8.4 lg CFU / mL for 21 days after storage at 4°C.

Images