Method for promoting debittering and active substance conversion of sea-buckthorn juice by dual-strain synergistic fermentation

Abstract

The application is suitable for the technical field of sea buckthorn juice processing, and provides a method for promoting the debittering and active substance conversion of sea buckthorn juice through double-strain synergistic fermentation, which comprises the following steps: inoculating Lactobacillus plantarum and Lactobacillus paracasei into sea buckthorn juice for fermentation treatment, the Lactobacillus plantarum and Lactobacillus paracasei account for 3% of the volume of the sea buckthorn juice, and the viable cell count in the sea buckthorn juice is 4×10 7 CFU / g-4.5×10 7 CFU / g. The application adopts Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus 660321 to construct a specific double-strain system, can efficiently utilize the endogenous nutrients in sea buckthorn juice, solves the pain points of incomplete debittering, bitter rebound and insufficient fermentation power in traditional fermentation, blocks the accumulation of bitter substances from the metabolic level, simultaneously accelerates the enrichment of beneficial organic acids such as lactic acid and free delicious and sweet amino acids, and finally realizes the triple effects of significantly reducing the bitterness of fermented sea buckthorn juice, making the taste clear and coordinated, and greatly improving the active ingredients.

Description

Technical Field

[0001] This invention belongs to the field of sea buckthorn juice processing technology, and in particular relates to a method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains. Background Technology

[0002] Sea buckthorn, a plant used both as food and medicine, is rich in flavonoids, polyphenols, vitamins, and other bioactive components. Its fruit possesses significant antioxidant and gut microbiota-regulating health benefits, making it a high-quality raw material for functional fermented beverages. However, sea buckthorn juice has a strong, astringent, and characteristic bitter substances, resulting in a naturally bitter taste that severely impacts market acceptance. Therefore, debittering and quality improvement are crucial for sea buckthorn juice fermentation. Currently, debittering technologies for sea buckthorn juice are mainly divided into three categories: physical debittering, chemical debittering, and biological debittering. Among these, biological debittering (especially lactic acid bacteria fermentation debittering) has become a major research technology because it preserves the product's naturalness and simultaneously improves the utilization rate of active ingredients. Lactic acid bacteria can metabolize and degrade bitter precursors and undesirable flavor precursors in sea buckthorn juice, while simultaneously promoting the conversion of active ingredients such as polyphenols and flavonoids. However, single-strain fermentation suffers from long fermentation cycles, incomplete debittering, and limited synergistic effects on active ingredients. Therefore, selecting dual-strain fermentation is an important strategy for achieving efficient debittering and the release and conversion of active ingredients.

[0003] Current research on dual-strain fermentation of sea buckthorn juice still has significant limitations: First, the strain combinations lack specificity, often using arbitrary combinations of *Lactobacillus plantarum* with *Lactobacillus casei*, *Lactobacillus brevis*, etc., without focusing on the dual objectives of "efficient debittering + activity enhancement" to screen for specific strains. The synergistic effect between strains is weak, with debittering rates often below 40%, and the utilization rate of active ingredients such as flavonoids and polyphenols cannot be simultaneously improved. Second, while some studies mention the combination of *Lactobacillus plantarum* and *Lactobacillus paracasei*, this is only used for dairy product fermentation, not for sea buckthorn juice fermentation, and the synergistic mechanism between the two in the degradation of bitter substances and the conversion of active ingredients is not clearly defined. Third, existing dual-strain fermentation of sea buckthorn juice requires the addition of exogenous sweeteners, masking agents, and bitterness reducers to assist in debittering, which damages the product's naturalness and does not meet consumer health needs. Fourth, the fermentation cycle is often as long as 48-72 hours, resulting in low degradation rates of bitter substances and utilization rates of active ingredients below 60%, making it difficult to balance taste and function.

[0004] In summary, existing dual-strain fermentation technology for sea buckthorn juice suffers from problems such as unreasonable strain combinations, limited debittering effect, and low conversion rate of active ingredients. There are currently no research reports on screening *Lactobacillus plantarum* and *Lactobacillus paracasei* to construct a specific dual-strain system tailored to the characteristics of sea buckthorn juice products, achieving efficient debittering and simultaneous enhancement of active ingredients without exogenous regulators. Summary of the Invention

[0005] The purpose of this invention is to provide a method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains, aiming to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation with two strains includes the following steps:

[0008] Lactobacillus plantarum and Lactobacillus paracasei were mixed and inoculated into sea buckthorn juice for fermentation. The Lactobacillus plantarum and Lactobacillus paracasei comprised 3% of the volume of the sea buckthorn juice, and the viable bacterial count in the sea buckthorn juice was 4 × 10⁻⁶. 7 CFU / g - 4.5 × 10 7 CFU / g.

[0009] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0010] This invention employs a specific dual-strain system constructed using *Lactobacillus plantarum* SC-5 and *Lactobacillus paracasei* Jlus 660321. *Lactobacillus plantarum* SC-5 degrades bitter precursors and promotes the conversion of flavonoids and polyphenols, while *Lactobacillus paracasei* Jlus 660321 regulates undesirable flavors and optimizes taste harmony. The co-fermentation process of *Lactobacillus plantarum* SC-5 and *Lactobacillus paracasei* Jlus 660321 results in the following: In the early stage of fermentation, *Lactobacillus plantarum* SC-5 rapidly proliferates and produces acid, providing a suitable acidic environment for the enzymatic hydrolysis of bitter substances; in the later stage, *Lactobacillus paracasei* Jlus 660321 dominates the conversion of bitter substances and flavor regulation. Furthermore, the acidic environment of the sea buckthorn juice itself, combined with the lactic acid produced by the mixed bacterial metabolism, exhibits outstanding synergistic metabolic capabilities, enabling rapid colonization and fermentation, inhibiting the growth of bitter-producing bacteria, and simultaneously promoting the conversion of bound total phenols and total flavonoids into highly active free forms. This significantly increases the content of active ingredients and improves bioavailability, achieving the effect of removing bitterness without reducing activity.

[0011] Compared to existing single-strain or random mixed-strain fermentation technologies, this dual-strain method can efficiently utilize the endogenous nutrients in sea buckthorn juice, solving the pain points of incomplete debittering, bitterness rebound, and insufficient fermentation power in traditional fermentation. It blocks the accumulation of bitter substances at the metabolic level and simultaneously accelerates the enrichment of beneficial organic acids such as lactic acid and free umami and sweet amino acids. Ultimately, it achieves a triple effect of significantly reduced bitterness, refreshing and harmonious taste, and greatly enhanced active ingredients in fermented sea buckthorn juice, meeting the market demand for natural functional beverages. Attached Figure Description

[0012] Figure 1 This is a graph showing the change in total phenol content provided in an embodiment of the present invention;

[0013] Figure 2This is a graph showing the change in total flavonoid content provided in an embodiment of the present invention;

[0014] Figure 3 Radar image of the sea buckthorn juice electronic nose provided in an embodiment of the present invention;

[0015] Figure 4 Radar image of the seabuckthorn juice electronic tongue provided in an embodiment of the present invention;

[0016] In the attached figure, *** represents a highly significant difference between groups (P < 0.001), and ** represents a significant difference between groups (P < 0.01). Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] The Lactobacillus plantarum SC-5 used in the embodiments of the present invention has been disclosed in patent application No. 202111068301.4, entitled "A strain with biogenic amine reduction activity and its use".

[0019] Lactobacillus paracasei Jlus 660321 has been disclosed in patent application No. 202510807174.7, entitled "A strain of Lactobacillus paracasei Jlus 660321 with auxiliary functions of lowering blood lipids and cholesterol and its application".

[0020] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0021] Comparative Example 1: A method for processing sea buckthorn juice, comprising the following steps:

[0022] The selected sea buckthorn berries were washed and juiced, then centrifuged (5000 rpm, 10 min), filtered through gauze, and the pH was adjusted to 4.5 before sterilization (65 ℃, 30 min) and cooling.

[0023] Example 1: Based on Comparative Example 1, Lactobacillus plantarum SC-5 was inoculated into sea buckthorn juice for fermentation treatment. Lactobacillus plantarum SC-5 accounted for 3% of the volume of sea buckthorn juice, and fermentation was carried out at 37°C for 72 hours.

[0024] Example 2: Based on Comparative Example 1, Lactobacillus paracasei Jlus 660321 was inoculated into sea buckthorn juice for fermentation treatment, and Lactobacillus plantarum SC-5 accounted for 3% of the volume of sea buckthorn juice. Fermentation was carried out at 37°C for 72 hours.

[0025] Example 3: Based on Comparative Example 1, Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus 660321 were mixed and inoculated into sea buckthorn juice for fermentation. The volume ratio of Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus 660321 was 3% of the volume of sea buckthorn juice, and fermentation was carried out at 37°C for 72 hours.

[0026] Example 4: Based on Comparative Example 1, *Lactobacillus plantarum* SC-5 and *Lactobacillus paracasei* Jlus 660321 were mixed and inoculated into sea buckthorn juice for fermentation. The volume ratio of *Lactobacillus plantarum* SC-5 to *Lactobacillus paracasei* Jlus 660321 was 3% of the sea buckthorn juice volume. At this time, the viable bacteria count in the sea buckthorn juice system was 4.3 × 10⁻⁶. 7 CFU / g, fermented at 37℃ for 72 hours.

[0027] Analysis and testing:

[0028] 1. Determination of total phenol content:

[0029] Sample pretreatment: Mix 0.2 mL of sea buckthorn juice sample with 0.8 mL of anhydrous ethanol, centrifuge to extract the supernatant;

[0030] Plotting the standard curve: Add standard solution + 80% ethanol solution to each centrifuge tube to obtain solutions with concentrations of 0, 40, 80, 120, 160, and 200 μg / mL, respectively. Then, add 0.5 mL of Folin-Ciocalteu solution sequentially, react for 5 min, and then add 0.35 mL of sodium carbonate solution sequentially. After reacting for 30 min, measure the absorbance value at 765 nm.

[0031] Determination of the sample: Take 0.1 mL of the supernatant of the above sample, add 0.5 mL of Folin-Ciocalteu, react for 5 min, then add 0.35 mL of sodium carbonate solution, react for 30 min, and measure the absorbance at 765 nm. Calculate the gallic acid equivalent of the total phenols according to the standard curve.

[0032] 2. Determination of total flavonoid content:

[0033] Sample pretreatment: Mix 0.2 mL of sea buckthorn juice sample with 0.8 mL of anhydrous ethanol, centrifuge to extract the supernatant;

[0034] Plotting the standard curve: Add standard solution + 80% ethanol solution to centrifuge tubes to obtain solutions with concentrations of 0, 100, 200, 300, 400, and 500 μg / mL, respectively. Add 60 μL of sodium nitrite solution to each tube and react for 6 min. Then add 60 μL of aluminum chloride solution and react for another 6 min. Finally, add 800 μL of sodium hydroxide solution and react for 15 min. Measure the absorbance at 510 nm.

[0035] Sample determination: Take 0.1 mL of the supernatant of the above sample, add 60 μL of sodium nitrite solution, react for 6 min, add 60 μL of aluminum chloride solution, react again for 6 min, then add 800 μL of sodium hydroxide solution, react for 15 min, and measure the absorbance at 510 nm.

[0036] 3. Organic acid analysis:

[0037] Take 5 g of sea buckthorn juice sample and mix it with 20 mL of 0.09 mol / L sulfuric acid solution. Place the mixture in an ultrasonic extractor and extract ultrasonically for 60 min. After ultrasonic treatment, centrifuge the mixture at 10000 r / min for 10 min and collect the supernatant. Purify the supernatant using a C18 solid-phase extraction column and filter it through a 0.22 μm filter membrane. Collect the filtrate in a 2 mL brown sample vial and store it at -20℃ for analysis. The chromatographic column used is a Hichrom Alltech OA-1000 organic acid analysis column (300 mm × 6.5 mm, particle size 9 μm). The mobile phase is 0.009 mol / L sulfuric acid solution, the flow rate is set to 0.6 mL / min, the injection volume is 10 μL, and the detection wavelength is 215 nm.

[0038] 4. Amino acid analysis:

[0039] The determination of free amino acids was performed using an LA8080 automatic analyzer (Hitachi, Japan). 2 g of sea buckthorn juice sample was accurately weighed, and free amino acids were extracted using 5% sulfosalicylic acid solution. After centrifugation (10000 rpm, 10 min), the supernatant was filtered through a 0.22 μm microporous membrane. The filtrate was appropriately diluted with 0.02 mol / L hydrochloric acid solution to a suitable concentration range and used as the test solution. The sample was stored in the dark and refrigerated at 4℃ during processing. Separation was performed using a dedicated pH 4.6×60-2622 column with a lithium-ion buffer system as the mobile phase and a gradient elution program. Post-column derivatization was performed using a ninhydrin reaction system at a reaction temperature of 135℃. The injection volume was 1-10 μL (adjusted according to the sample concentration); after sample pretreatment, 1 μL was injected into the chromatograph for analysis; each sample was repeated 3 times; amino acids were classified into three categories according to their taste properties: sweet amino acids (glycine, alanine, serine, threonine, proline, cysteine), umami amino acids (glutamic acid, aspartic acid), and bitter amino acids (valine, leucine, isoleucine, phenylalanine, tyrosine, methionine, lysine, arginine, histidine) for statistical analysis.

[0040] 5. Analysis of electronic nose and electronic tongue:

[0041] Accurately weigh 5.0 g of sea buckthorn juice sample and place it in a 100 mL volumetric flask. Add distilled water to the mark and extract by ultrasonication in a 50℃ water bath for 30 minutes. After centrifugation (8000 rpm, 10 min) and filtration (0.45 μm microporous membrane), the supernatant was collected and stored in a 4℃ refrigerator for analysis. The fingerprint analysis of volatile components was performed using a PEN3 portable electronic nose system (Airsense, Germany). The taste analysis was performed using the INSENT SA402B taste analysis system (Japan).

[0042] 6. Results Analysis

[0043] 6.1 Total Phenolic Content Analysis

[0044] The total phenol content of sea buckthorn juice showed significant strain and ratio dependence differences with the fermentation process: In Example 2, the total phenol content did not change significantly throughout the fermentation process and remained at the initial level, indicating that Lactobacillus paracasei Jlus 660321 alone had limited ability to release and transform bound phenolic substances in sea buckthorn juice; Although the total phenol content of Examples 1 and 3 increased significantly with fermentation time, the increase was limited, reaching only about 531 mg / L and 570 mg / L respectively after 3 days of fermentation; In contrast, Example 4 showed a significant synergistic effect, with the total phenol content reaching about 630 mg / L after 3 days of fermentation, significantly higher than the other three groups; This result indicates that when Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus 660321 were mixed inoculated at a volume ratio of 9:1, the synergistic metabolic action of the two strains could efficiently degrade the cell wall and promote the transformation of bound phenolic substances into free phenolic substances, thereby maximizing the enrichment of total phenol content.

[0045] 6.2 Analysis of total flavonoid content

[0046] Total flavonoids, as the hallmark active ingredient of sea buckthorn, showed a continuous and significant increasing trend during the dual-strain fermentation process (p<0.05), with the strain and ratio having a more significant impact: In Example 2, the total flavonoid content did not increase significantly throughout the fermentation process, remaining at an initial level of approximately 300 mg / L, indicating that the single *Lactobacillus paracasei* Jlus660321 had a weak ability to release flavonoids; Although Examples 1 and 3 significantly increased the total flavonoid content, they only reached approximately 3215 mg / L and 3159 mg / L respectively after 3 days of fermentation, showing a limited increase; while in Example 4, the total flavonoid content showed an explosive increase during fermentation, reaching approximately 3684 mg / L after 3 days, significantly higher than all other groups. This result fully demonstrates that *Lactobacillus plantarum* SC-5 and *Lactobacillus paracasei* Jlus660321 have a strong flavonoid release capacity. When 660321 is mixed and inoculated at a volume ratio of 9:1, it can maximize the release and transformation of flavonoid active ingredients in sea buckthorn juice through efficient cell wall disruption and enzymatic hydrolysis. Its synergistic effect is significantly better than that of single strains and mixed strains in equal proportions, providing key technical support for improving the functional activity of sea buckthorn juice.

[0047] 6.3 Organic acid analysis, as shown in Table 1.

[0048] Table 1 Organic acid content of fermented sea buckthorn juice

[0049]

[0050] Compared with Comparative Example 1, the organic acid content in sea buckthorn juice showed significant differences after 3 days of fermentation with different strains and ratios, resulting in a fundamental reshaping of the overall acidity profile and flavor profile: lactic acid rapidly increased from 126.35 mg / 100g to 235.12 mg / 100g, an increase of nearly 1.86 times in Example 4, becoming the dominant organic acid in the fermentation system; at the same time, the content of irritating organic acids such as malic acid, oxalic acid, and pyruvic acid decreased significantly, especially malic acid, which decreased from 813.74 mg / 100g to 350.90 mg / 100g, a decrease of more than 56%, greatly reducing the original irritating sour and bitter taste of sea buckthorn juice; in addition, the content of flavor organic acids such as acetic acid, citric acid, and succinic acid increased simultaneously, jointly constructing a rich, mellow, and harmonious fermentation acidity system; the above results indicate that the *Lactobacillus plantarum* SC-5 and *Lactobacillus paracasei* Jlus proposed in the embodiments of this invention are effective. The 9:1 dual-strain synergistic fermentation process of 660321 can alleviate the unpleasant bitter and sour taste of sea buckthorn juice from the root by efficiently degrading irritating organic acids. At the same time, it can selectively enrich lactic acid and flavor organic acids, achieving a softening of acidity and an upgrade in taste without the need to add exogenous acid-reducing agents. This is significantly better than the effects of single strains and mixed strains in equal proportions.

[0051] 6.4 Amino acid analysis, as shown in Table 2.

[0052] Table 2. Amino acid content in sea buckthorn juice before and after fermentation.

[0053]

[0054]

[0055] As shown in Table 2, after 3 days of fermentation with different strains and ratios, the amino acid composition of sea buckthorn juice underwent significant and directional changes. In Example 4, both umami amino acids (aspartic acid and glutamic acid) and sweet amino acids (threonine, serine, alanine, proline, etc.) were significantly enriched. Aspartic acid increased from 9.95 mg / 100g to 15.40 mg / 100g, glutamic acid from 5.61 mg / 100g to 9.72 mg / 100g, and proline from 21.84 mg / 100g to 35.94 mg / 100g, contributing to the umami flavor of the fermented sea buckthorn juice. The enhancement of sweetness provides the core material basis; while the main bitter amino acids such as valine, leucine, tyrosine, and phenylalanine all showed a significant decreasing trend. Valine decreased from 3.49 mg / 100g to 1.23 mg / 100g, tyrosine from 1.80 mg / 100g to 0.52 mg / 100g, and leucine from 1.60 mg / 100g to 0.72 mg / 100g, directly degrading the source of bitterness and significantly weakening the original bitterness of sea buckthorn juice. The above results indicate that the dual-strain synergistic fermentation process of Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus 660321 with a volume ratio of 9:1 proposed in this embodiment of the invention can accurately achieve the flavor regulation of "directional enrichment of umami and sweet amino acids and efficient degradation of bitter amino acids" without the need for exogenous regulators. The effect is significantly better than that of single strains and equal proportion mixed strains, effectively breaking through the bottleneck of "prominent bitterness and thin flavor" in unfermented sea buckthorn juice.

[0056] 6.5 Electronic nose analysis

[0057] The sensitive substances corresponding to the sensors are shown in Table 3:

[0058] Table 3

[0059]

[0060] like Figure 3As shown, compared with Comparative Example 1, the volatile flavor profiles of sea buckthorn juice after 3 days of fermentation with different strains and ratios exhibited significant differentiation characteristics, which highly corresponded to the changes in organic acids and amino acids, confirming that strain metabolism is the core driving force for flavor reshaping: Comparative Example 1 only showed high response values ​​on sensors such as W2W and W3C, which concentratedly reflected the original astringent and pungent flavor characteristics of sea buckthorn juice, with a single overall flavor level; while Example 4 showed a significant decrease in response values ​​on the above sensors, while the response values ​​in multiple positive flavor dimensions such as W2S, W1S, and W1C were greatly increased, accurately reflecting the dual regulatory advantages of the synergistic metabolism of the two strains: Lactobacillus plantarum SC-5 efficiently degraded the original aromatic and ammonia precursors in sea buckthorn juice that caused astringency and bitterness with its vigorous metabolic activity, thereby weakening the bitter and astringent off-flavor of sea buckthorn juice from the root, while Lactobacillus paracasei Jlus660321 participated in the process. The synthesis of pleasant volatile substances such as alcohols and esters during fermentation was further enhanced. When the two were combined in a 9:1 ratio, they formed a complementary metabolic synergy, which significantly improved the enrichment efficiency of positive flavor substances and achieved a richer and more optimized flavor profile. In contrast, the single strain group and the mixed strain group with equal proportions had weaker ability to weaken unpleasant flavors and enrich positive aromas than in Example 4 due to their single metabolic pathways or insufficient synergistic effects. The above results fully demonstrate the superiority of the dual-strain fermentation process of the present invention. Without the addition of any exogenous flavor modifiers, the synergistic metabolic action of Lactobacillus plantarum SC-5 and Lactobacillus paracasei Jlus660321 can fundamentally improve the flavor quality of sea buckthorn juice, upgrading it from "original bitterness" to a harmonious flavor system of "original characteristic aroma + fermented mellow aroma". The richness and harmony of the flavor are significantly improved compared to the unfermented group.

[0061] 6.6 Electronic Tongue Analysis

[0062] like Figure 4 As shown, although Comparative Example 1 possesses the original basic flavor of sea buckthorn, its flavor profile and harmony are extremely poor. The negative flavor response values ​​such as bitterness, astringency, and after-bitterness and after-astringency are significantly high, resulting in poor palatability. Furthermore, positive flavors such as freshness and sweetness are extremely lacking, making it difficult to meet the flavor requirements of beverages. Examples 1 and 2 can only slightly alleviate some astringency and cannot fundamentally improve the problem of hindered synthesis of flavor substances caused by insufficient strain metabolism, thus having limited flavor enhancement effects. In contrast, Examples 3 and 4 can significantly improve the positive flavor response values ​​such as freshness, sweetness, and richness and reduce the levels of negative flavors such as bitterness and astringency by activating the synergistic metabolic activity of the two strains and constructing a stable and dominant fermentation microecology. Among them, Example 4 has the most outstanding optimization effect. Its bitterness, astringency, and after-bitterness and after-astringency response values ​​are significantly lower than those of Comparative Example 1. At the same time, the response values ​​of freshness, sweetness, and richness are greatly improved, and the taste harmony is significantly optimized, achieving a quality upgrade of "removing bitterness and enhancing freshness, and harmonizing flavors," thus solving the core bottleneck problem of "prominent bitterness and obvious sourness and astringency" in sea buckthorn juice.

[0063] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains, characterized in that, Includes the following steps: Lactobacillus plantarum and Lactobacillus paracasei were mixed and inoculated into sea buckthorn juice for fermentation. The Lactobacillus plantarum and Lactobacillus paracasei comprised 3% of the volume of the sea buckthorn juice, and the viable bacterial count in the sea buckthorn juice was 4 × 10⁻⁶. 7 CFU / g - 4.5 × 10 7 CFU / g; The Lactobacillus plantarum strain is Lactobacillus plantarum SC-5, which was deposited on March 31, 2021, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 22102. The Lactobacillus paracasei is Lactobacillus paracasei Jlus 660321, which was deposited on March 24, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 33962.

2. The method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains according to claim 1, characterized in that, The *Lactobacillus plantarum* and *Lactobacillus paracasei* were mixed and inoculated at a volume ratio of 9:

1.

3. The method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains according to claim 1, characterized in that, The fermentation process was carried out at a temperature of 37°C for 72 hours.

4. The method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains according to claim 1, characterized in that, The preparation process of the sea buckthorn juice is as follows: the sea buckthorn fruit is washed and juiced, then centrifuged, filtered, the pH is adjusted to 4.5, heated for sterilization, and then cooled.

5. The method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains according to claim 4, characterized in that, The centrifugation process was carried out at a rate of 5000 rpm for 10 minutes.

6. The method for promoting debittering and conversion of active substances in sea buckthorn juice through synergistic fermentation of two strains according to claim 4, characterized in that, The temperature for the heat sterilization treatment is 65°C and the time is 30 minutes.

Images