Lactobacillus buchneri and application thereof in preparation of nutritional and healthy fruit and vegetable juice

Abstract

The invention discloses a Lactobacillus buchneri strain with high yield of gamma-aminobutyric acid and application of the Lactobacillus buchneri strain in preparation of nutritional and healthy fruit and vegetable juice. The strain is Lactobacillus buchneri GM3, and is preserved in the Guangdong Microbial Culture Collection Center on January 9, 2025, and the preservation number of the strain is GDMCC No: 65737. The invention further discloses a preparation method of the Lactobacillus buchneri strain. The strain not only has the capacity of producing gamma-aminobutyric acid at high yield, but also has good acid resistance, cholate resistance and gastrointestinal fluid resistance, and is very suitable for fermentation production of fermented fruit and vegetable juice. The contents of gamma-aminobutyric acid and flavonoid substances in fruit and vegetable juice fermented by the strain are greatly increased, and the nutritional value of the fruit juice is remarkably increased; moreover, the contents of alkaloid substances and total sugar are remarkably reduced, so that the tea is healthier, and the flavor is better and more unique. The Lactobacillus buchneri GM3 is a safe lactic acid bacterium, and the Lactobacillus buchneri GM3 and the technology for producing fruit and vegetable juice through fermentation of the Lactobacillus buchneri GM3 have very good application value and market prospect.

Description

Technical Field

[0001] The present invention belongs to the technical fields of microbial agents and food processing. More specifically, it relates to a strain of Lactobacillus brenis and its application in the preparation of nutritious and healthy fruit and vegetable juices. Background Art

[0002] γ-Aminobutyric acid (GABA) is a natural four-carbon non-protein amino acid widely present in animals, plants and microorganisms, and is an inhibitory neurotransmitter in the mammalian central nervous system. Research shows that GABA is widely used in clinical studies, including the treatment of insomnia, hypertension, stress, depression, enhancement of memory, reduction of obesity, and increase of serum growth hormone levels. The content of GABA in the human body decreases year by year with age, and it is necessary to supplement GABA through exogenous foods or health products to maintain the body's needs. Therefore, the development of GABA-rich foods has become a key research direction in the food field. Common production methods of GABA include chemical synthesis, plant enrichment extraction, and microbial fermentation. Among them, chemically synthesized GABA has high purity, but high production cost, unstable reaction conditions, large raw material residues, and poor safety. Plant enrichment extraction is also less used in the industrial field due to its high cost. Microbial fermentation has the characteristics of high yield, low cost, simple process flow, and high safety, and can meet the complex needs of industries such as food and pharmaceuticals. It is the most excellent technical route for producing GABA. Fruits and vegetables, as a highly nutritious natural food rich in physiologically active ingredients such as polysaccharides, minerals, and vitamins, are good fermentation substrates for high-yield GABA strains. Among them, litchi is widely used in the development of GABA-rich functional products because of its relatively high GABA content in fruits and vegetables.

[0003] The most crucial part of the microbial fermentation method is the fermenting bacteria. Microorganisms that produce GABA mainly include Escherichia coli, lactic acid bacteria, yeast, and a few molds. Among them, lactic acid bacteria are the optimal choice due to their relatively high safety factor and the good catalytic activity of their glutamate decarboxylase. Currently reported lactic acid bacteria that produce GABA mainly include Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus pentosus. For example, the applicant's CN111117926A discloses a strain with high γ-aminobutyric acid production and its application in preparing γ-aminobutyric acid-rich fruit juice. The strain is Lactobacillus plantarum HU-C2W, which is used for fermenting to prepare fruit juice rich in γ-aminobutyric acid. The GABA content in the obtained fruit juice after fermentation is 135 mg / 100 mL, which is a 50.0% increase compared to 90 mg / 100 mL before fermentation. However, the increase is still insufficient. Moreover, a large number of studies have shown that there are significant differences in the GABA production ability among different strains. In the method of enriching GABA by bacterial fermentation, the selection of strains is particularly important. Additionally, many fruit and vegetable raw materials have a high acidity. For example, the total acid in lemon, passion fruit, etc. is as high as 25 g / L. Such highly acidic conditions will inhibit the fermentation of lactic acid bacteria. Therefore, when fermenting to prepare low-sugar and GABA-rich functional beverages using fruits and vegetables as raw materials, not only the selection of GABA-producing strains but also the acid tolerance of the strains need to be considered.

[0004] In addition, flavonoids in fruit and vegetable juices are a class of polyphenolic secondary metabolites widely present in plants, with various biological activities such as antioxidant, anti-inflammatory, and anti-cancer effects. They are not only important functional components in fruit and vegetable juices but also affect the color, flavor, and stability of fruit and vegetable juices. Alkaloids in fruit and vegetable juices are secondary metabolites produced by plants during evolution and may cause certain harm to the human body. Most of them are medicinal components and are not suitable for daily intake. For example, sinapine can stimulate the human intestine and digestive system, causing gastrointestinal symptoms such as diarrhea and abdominal pain, and may also have a certain toxic effect on the thyroid and reproductive systems after long-term consumption; solanine can cause nervous system disorders, and colchicine is related to liver and kidney damage; moreover, alkaloids usually have a bitter or spicy taste, and some may also bring a metallic or astringent taste. The reduction of their content is of great significance for fruit and vegetable juices. The effects of fermentation by different strains on the content changes of components in fruit and vegetable juices are uncertain. Therefore, it is of great significance and market prospect to explore superior strains that can produce high levels of γ-aminobutyric acid, are acid-tolerant, and can reduce the alkaloid content and increase the flavonoid content in fruit and vegetable juices through fermentation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and deficiencies of the above-mentioned existing strains, and to provide a strain with high GABA-producing ability and strong acid tolerance, and to use it to ferment fruit and vegetable juices to reduce the alkaloid content and increase the flavonoid content.

[0006] The object of the present invention is to provide a strain of Lentilactobacillus buchneri GM3 and its bacterial agent.

[0007] Another object of the present invention is to provide a composition for producing fruit and vegetable juices.

[0008] Another object of the present invention is to provide a preparation method of fermented fruit and vegetable juices rich in γ-aminobutyric acid and flavonoids, low in sugar and alkaloids, and the obtained fermented fruit and vegetable juices.

[0009] The above objects of the present invention are achieved by the following technical solutions:

[0010] A strain of Lentilactobacillus buchneri GM3 was deposited at the Guangdong Provincial Microbial Culture Collection Center on January 9, 2025, with the deposit number GDMCC No: 65737. The deposit address is on the 5th floor of Building 59, No. 100 Compound, Xianlie Middle Road, Guangzhou (Institute of Microbiology, Guangdong Academy of Sciences).

[0011] This strain was isolated and screened from Guizhou pickle mother liquor and has the advantage of high γ-aminobutyric acid production. Compared with the original litchi juice, the γ-aminobutyric acid content in the litchi juice fermented by this strain is greatly increased by 77.55%, and the sugar content is reduced by 23.53%; moreover, the flavonoid content increases by 43.47% after fermentation, and the contents of chalcone, neohesperidin, and epigallocatechin 3-O-gallate (EGCG) all increase significantly, and the total alkaloid content decreases by 57.74%, and the contents of antinutritional factors such as sinapine, valerianine, and cucurbitacin all decrease significantly. The fermentation by this strain can not only significantly improve the nutritional value of fruit and vegetable juices, but also make them healthier and have a more unique flavor. Moreover, this strain has good acid tolerance, bile salt tolerance, and gastrointestinal fluid tolerance; when cultured in MRS liquid medium containing 4% glutamic acid for 48 h, the GABA yield can reach 5.14 g / L. This strain has very excellent application value in fermenting fruit and vegetable juices.

[0012] Therefore, the present invention also claims to protect the bacterial agent containing the above-mentioned Lentilactobacillus buchneri GM3, and the application of the above-mentioned Lentilactobacillus buchneri GM3 or the bacterial agent in the preparation of fruit and vegetable juices.

[0013] Preferably, it is used in the preparation of fruit and vegetable juices with increased γ-aminobutyric acid and flavonoid contents and reduced sugar and alkaloid contents.

[0014] Based on this, the present invention also provides a composition for producing fruit and vegetable juice, which comprises fruits and vegetables and a starter, and the starter contains the Lactobacillus bramii GM3.

[0015] The present invention also provides a method for increasing the contents of γ-aminobutyric acid and flavonoids in fruit and vegetable juice and reducing the contents of sugar and alkaloids, that is, a preparation method of a nutritious and healthy fermented fruit and vegetable juice (the so-called nutritious and healthy means rich in γ-aminobutyric acid and flavonoids, and low in sugar and alkaloids). Specifically, a starter containing the Lactobacillus bramii GM3 is used to ferment the fruit and vegetable juice, and a fermented fruit and vegetable juice rich in γ-aminobutyric acid and flavonoids and low in sugar and alkaloids can be obtained.

[0016] Optionally, the fruit raw materials of the fruit and vegetable juice can be litchi, pineapple, lemon, passion fruit, roselle, etc.

[0017] As a reference, the preferred fermentation conditions are as follows: the fermentation is carried out at 30°C to 40°C for 24 to 72 hours. More preferably, the fermentation is carried out at 37°C for 48 hours. More preferably, it is static fermentation.

[0018] In addition, as a reference, the preferred fermentation conditions are as follows: the amount of the starter inoculated into the fruit and vegetable juice is such that the original bacterial concentration in the fruit and vegetable juice is not less than 7 log CFU / mL.

[0019] More specifically, as a reference implementation example, the preparation method of the fruit and vegetable juice comprises the following steps:

[0020] S1. The strain is inoculated into MRS broth and activated and cultured for three generations to obtain a bacterial suspension;

[0021] S2. Select fruits and vegetables without diseases and pests and ripe (such as litchi), make them into pulp, filter with 120 - 300 meshes (preferably 200 meshes), and sterilize to obtain fruit and vegetable juice;

[0022] S3. After washing the bacterial suspension obtained in S1 with sterile normal saline, inoculate it into the fruit and vegetable juice for fermentation.

[0023] Preferably, the activation inoculation amount in step S1 is 2%.

[0024] Preferably, the culture temperature in step S1 is 37°C and the culture time is 22 hours.

[0025] Preferably, the sterilization in step S2 is preferably pasteurization.

[0026] Preferably, the pasteurization temperature in step S2 is 85 - 90°C for 15 s.

[0027] More preferably, the pasteurization temperature in step S2 is 88°C for 15 s.

[0028] Preferably, the fermentation in step S3 is carried out at 30°C to 40°C for 24 to 72 hours.

[0029] More preferably, the fermentation in step S3 is static fermentation at 37°C for 48 hours.

[0030] The fermented fruit and vegetable juice produced by the above fermentation, such as the fermented litchi juice prepared from litchi as the raw material, is also within the protection scope of the present invention.

[0031] Taking the fermented litchi juice as an example, compared with the litchi juice before fermentation, the contents of γ-aminobutyric acid and flavonoids in the fermented litchi juice are significantly increased, while the contents of total sugar and alkaloid substances are significantly decreased.

[0032] Specifically, in the fermented litchi juice, the content of γ-aminobutyric acid is not less than 1.74 g / L, and the content of total sugar is not higher than 144 mg / mL.

[0033] Compared with the litchi juice before fermentation, the content of alkaloid substances in the fermented litchi juice is decreased by 50 - 60%, and the content of flavonoid substances is increased by 40 - 50%.

[0034] More specifically, compared with the litchi juice before fermentation, the content of alkaloid substances in the fermented litchi juice is decreased by 57.74%, and the content of flavonoid substances is increased by 43.47%.

[0035] Specifically, the alkaloid substances include sinapine, valerianine, cucurbitacin, 4-aminophenol, isoquinoline, etc.

[0036] Among them, the content of sinapine is decreased by 90 - 99%, the content of valerianine is decreased by 90 - 99%, the content of cucurbitacin is decreased by 60 - 70%, the content of 4-aminophenol is decreased by 56 - 65%, the content of isoquinoline is decreased by 60 - 70%, and the content of other alkaloids is decreased by 50 - 60%.

[0037] Specifically, the content of sinapine is decreased by 95.35%, the content of valerianine is decreased by 93.29%, the content of cucurbitacin is decreased by 67.28%, the content of 4-aminophenol is decreased by 61.26%, the content of isoquinoline is decreased by 66.79%, and the content of other alkaloids is decreased by 57.53%.

[0038] Specifically, the flavonoid substances include chalcone, neohesperidin, epigallocatechin 3-O-gallate (EGCG), etc.

[0039] Among them, the content of chalcone is increased by 400 - 550%, the content of neohesperidin is increased by 800 - 950%, the content of epigallocatechin 3-O-gallate (EGCG) is increased by 1400 - 1600%, and the content of other flavonoid substances is increased by 30 - 50%.

[0040] Specifically, the chalcone content increased by 475.98%, the neohesperidin content increased by 888.68%, the gallocatechin 3-O-gallate (EGCG) content increased by 1556.72%, and the content of other flavonoids increased by 38.02%.

[0041] The present invention has the following beneficial effects:

[0042] A strain of Lentilactobacillus buchneri GM3 with high γ-aminobutyric acid production was screened and isolated from Guizhou pickle mother liquor in the present invention. The strain was shown to be a safe strain for consumption through hemolytic test and antibiotic sensitivity test. After inoculating this strain for 32 h of fermentation of litchi juice, the γ-aminobutyric acid content in litchi juice can be increased by more than 77.55%, the total sugar decreased by 23.53%, and the content of alkaloid substances decreased by 57.74%, while the content of flavonoid substances increased by 43.47%, significantly improving the nutritional value of litchi juice. Therefore, the Lentilactobacillus buchneri GM3 of the present invention is a superior strain for preparing fermented fruit and vegetable juices rich in γ-aminobutyric acid and flavonoid substances and low in sugar and alkaloids.

[0043] Since the fermentation of fruit and vegetable juices using this bacterium can significantly increase the γ-aminobutyric acid content therein, the fruit and vegetable juices can be rich in functional factors such as antidepressant, anti-anxiety, and sleep-aiding functions; the content of flavonoid substances is increased, including a significant increase in the content of chalcone and neohesperidin with biological activities such as anti-tumor, sedative, and antibacterial properties, and the content of gallocatechin 3-O-gallate (EGCG) also increases significantly during the fermentation process, which has strong antioxidant, anti-inflammatory, and immunomodulatory functional characteristics.

[0044] At the same time, the fermentation of fruit and vegetable juices using this bacterium can also reduce the total sugar and alkaloid contents therein. Among them, sinapine, valerianine, cucurbitacin, etc. are anti-nutritional factors and substances with bitter and astringent flavors, and fermentation significantly reduces their contents in fruit and vegetable juices, indicating that the functional activity of fruit and vegetable juices can be enhanced and the flavor of fruit and vegetable juices can be improved through fermentation.

[0045] In addition, Lentilactobacillus buchneri GM3, as a safe lactic acid bacterium, is one of the important types of probiotics and has various potential probiotic functions, which are closely related to aspects such as the intestinal flora, digestive system, and intestinal microecological balance of organisms. This bacterium has good acid tolerance, bile salt tolerance, and gastrointestinal fluid tolerance. Therefore, the Lentilactobacillus buchneri GM3 provided by the present invention and the technology for producing fruit and vegetable juices by fermenting fruits and vegetables with it have very good application value and market prospects. Description of the Drawings

[0046] Figure 1 It is the colony morphological characteristic diagram (a) and Gram staining diagram (b) of Lentilactobacillus buchneri GM3 on MRS medium.

[0047] Figure 2 Phylogenetic tree of Lactobacillus brantae GM3

[0048] Figure 3 Variation diagram of GABA content in litchi juice fermented by Lactobacillus brantae GM3

[0049] Figure 4 Variation diagram of total sugar content in litchi juice fermented by Lactobacillus brantae GM3 Specific implementation mode

[0050] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0051] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0052] Example 1 Screening, isolation and identification of Lactobacillus brantae GM3

[0053] 1. Screening and isolation

[0054] Gradient dilution separation method was used for screening and isolation: Take 1 mL of Guizhou pickle mother liquor, gradient dilute it 10 -1 -10 -7 , select the appropriate gradient (10 -6 ) 100 μL and coat it on MRS medium, culture at 37 °C for 48 h. Round milky white colonies with a sour smell appeared, and they were initially determined to be lactic acid bacteria. A total of 33 strains of suspected lactic acid bacteria were screened out by this method, and they were named GM1 - GM33 in sequence. Further pick single colonies for streak separation and purification for three generations, then place them in 20% glycerol tubes and store them in a -80 °C refrigerator.

[0055] 2. Screening of high-yield GABA strains

[0056] After activating the strains stored in 20% glycerol for three generations, inoculate them into the fermentation medium (MRS broth containing 4% glutamic acid) at an inoculation amount of 2%, culture at 37 °C for 48 h, centrifuge at 10000 r / min for 10 min, and obtain the lactic acid bacteria culture supernatant containing GABA. After detection by high performance liquid chromatography, the GM3 strain has a strong ability to produce GABA. The GABA content in the supernatant after fermentation by the GM3 strain is as high as 5.14 g / L. Therefore, GM3 was retained and stored in glycerol at -80 °C as the target strain.

[0057] 3. Physiological and biochemical identification of strain GM3

[0058] Inoculate the GM3 strain on an MRS agar plate, invert and culture at 37°C for 48 hours, and observe the growth of the colonies. At the same time, use an inoculation loop to pick a single colony of the strain, perform Gram staining, and observe the microscopic morphology of the strain under an optical microscope. Pick a single colony on a glass slide again, add 3% hydrogen peroxide solution, and observe whether bubbles are generated.

[0059] Results: The colonies of GM3 strain were milky white with smooth surface ( Figure 1 (a), the cells were rod-shaped, non-motile, and without spores under microscope; Gram staining was positive ( Figure 1 (shown in Figure b), facultative anaerobic, and the result of catalase contact test was negative.

[0060] 4. Molecular biological identification of strain GM3

[0061] The 16SrDNA sequencing of the GM3 strain was commissioned to Shanghai Meiji Biotechnology Co., Ltd. After the 16SrDNA sequence of the GM3 strain was measured, the 16SrRNA gene sequence of the strain was analyzed for homology on NCBI using the BLAST tool, and a phylogenetic tree of the GM3 strain was drawn.

[0062] The results showed that the homology between GM3 strain and Lentilactobacillus buchneri reached 99.9% (phylogenetic tree is attached Figure 2 ).

[0063] Based on the above identification, the GM3 strain belongs to Lentilactobacillus buchneri, and was deposited in the Guangdong Provincial Microbiological Culture Collection Center on January 9, 2025, with the deposit number GDMCC No: 65737; the deposit address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou (Institute of Microbiology, Guangdong Academy of Sciences).

[0064] Example 2 Identification of the growth probiotic properties of Lactobacillus buchneri GM3

[0065] 1. Acid resistance test of strains

[0066] After activation, the GM3 strain was inoculated at a 4% inoculum size into sterile MRS culture media with pH values of 2.5 and 3.0, and cultured at 37°C. The viable bacteria were counted by the dilution plate counting method at 0 h and 3 h, respectively. The MRS culture medium without acid treatment was used as a control, and the survival rate of the GM3 strain in acidic culture media with different pH values was calculated, that is, survival rate = S0 / S1, where S0 is the number of viable bacteria in the culture medium after pH adjustment; S1 is the number of viable bacteria in the untreated MRS culture medium.

[0067] The results are shown in Table 1. GM3 can grow well in an acidic environment with a pH of 3 and still maintain a survival rate of 56.91% in an environment with a pH of 2.5.

[0068] Table 1 Effects of different acid treatments for different times on the viable count of GM3 strain

[0069]

[0070] 2. Bile salt tolerance of the strain

[0071] GM3 was activated 3 times in MRS liquid medium and then inoculated into MRS liquid medium with bile salt mass fractions of 0%, 0.15%, 0.3%, and 0.45% at an inoculation amount of 4%. The viable count was determined by the dilution plating method at 0, 3, and 6 hours. The medium without added bile salt was used as a control to determine the survival rate of the strain in different bile salt concentrations. That is: survival rate = S0 / S1, where S0 is the viable count in the MRS medium with different bile salt concentrations; S1 is the viable count in the MRS medium.

[0072] The results are shown in Table 2. The GM3 strain still has good growth and reproduction ability under the condition of high bile salt concentration, indicating that the GM3 strain has good bile salt tolerance.

[0073] Table 2 Effects of different bile salt concentrations for different times on the viable count of GM3 strain

[0074]

[0075]

[0076] 3. Gastrointestinal fluid tolerance of the strain

[0077] GM3 strain was activated 3 times in MRS liquid medium and then inoculated into artificial gastric juice (pepsin with a mass fraction of 0.32% and NaCl with a mass fraction of 0.2%) at an inoculation amount of 4%. It was cultured at 37°C for 3 hours and the viable count was determined by the plate counting method. Subsequently, the bacterial suspension after being treated with artificial gastric juice for 3 hours was taken and inoculated into artificial intestinal juice (trypsin with a mass fraction of 0.1% and bile salt with a mass fraction of 0.3%) at an inoculation amount of 4%. It was cultured at 37°C for 6 hours, and the viable count was determined at 2, 4, and 6 hours respectively. The viable count in the untreated MRS medium was used as a control to determine the survival rate of the strain after being treated with artificial gastrointestinal fluid. That is: survival rate = S0 / S1, where S0 is the viable count in the artificial gastrointestinal fluid; S1 is the viable count in the MRS medium.

[0078] Through the simulated human gastrointestinal fluid digestion experiment, it can be seen from Table 3 that the survival rate of the strain remains 87.25% after being treated with gastric juice, and still maintains a survival rate of 33.33% after 6 hours of intestinal fluid treatment, indicating that the strain GM3 can resist the gastrointestinal environment and has certain probiotic characteristics.

[0079] Table 3 Gastrointestinal fluid tolerance of GM3 strain

[0080]

[0081] Example 3 Preparation of litchi juice by fermentation of Lactobacillus brueckii GM3

[0082] 1. A method for preparing litchi juice by fermentation of Lactobacillus brueckii GM3, the specific steps are as follows:

[0083] S1. Strain activation

[0084] After activating the GM3 strain for three generations, prepare it into a bacterial suspension, wash it 3 times with sterile normal saline, and set aside;

[0085] S2. Preparation of litchi original juice:

[0086] Select litchi fruits without pests and diseases and ripe ones, make them into pulp, filter through a 200-mesh sieve, and pasteurize at 88 °C for 15 s to obtain litchi original juice;

[0087] S2. Fermentation of litchi juice:

[0088] Inoculate the GM3 bacterial suspension into the fruit original juice to make the original bacterial concentration in the fruit original juice 7 log CFU / mL; then add 2% glutamic acid, and place it at 37 °C for static fermentation for 32 h to obtain litchi juice with lactic acid bacteria activity.

[0089] 2. Changes in the contents of γ-aminobutyric acid and total sugar in fermented litchi juice

[0090] Take the fermented litchi juice, centrifuge it at 10000 r / min at low temperature for 10 min, remove the supernatant, filter it with a 0.22 μm water-based filter head, and measure its GABA content by high performance liquid chromatography (HPLC).

[0091] Take the fermented litchi juice diluted 4000 times and measure its total sugar content by the phenol-sulfuric acid method.

[0092] The results of the γ-aminobutyric acid content after the lactic acid fermentation process of litchi juice are shown in Figure 3 , and the changes in the total sugar content are shown in Figure 4The results showed that after fermentation, the content of γ-aminobutyric acid in the fruit and vegetable juice was 1.74 g / L, an increase of 77.55% compared with 0.98 g / L before fermentation; the total sugar content was 144.608 mg / mL, a decrease of 23.53% compared with 189.118 mg / mL before fermentation.

[0093] 2. Content analysis of flavonoid and alkaloid metabolites in fermented litchi juice

[0094] Take 200 μL of the samples of litchi juice before and after fermentation, vortex for 10 s to mix evenly, then add 200 μL of 70% methanol containing internal standard extraction solution, vortex for another 15 min, centrifuge at 12,000 r / min at 4 °C for 3 min, take the supernatant, filter it with a microporous membrane (0.22 μm), and store it in a sample injection bottle. The determination of the compound components and contents before and after fermentation was carried out by using the widely targeted metabolomics technology based on UPLC-ESI-MS / MS. The extraction, detection, identification and quantification of its metabolites were all entrusted to Wuhan MetWare Biotechnology Co., Ltd. (www.MetWare.cn).

[0095] The change amounts of alkaloid metabolites and flavonoid metabolites are shown in Table 4 and Table 5. The results showed that after fermentation, the content of alkaloid substances in the litchi lactic acid bacteria fruit and vegetable juice with lactic acid bacteria activity decreased by 57.74%, among which the content of sinapine decreased by 95.35%, the content of valerianine decreased by 93.29%, and the content of cucurbitacin decreased by 67.28%. The content of flavonoid substances increased by 43.47%. Among them, the content of chalcone increased by 475.98% compared with the unfermented group, the content of neohesperidin increased by 888.68%, and the content of (-)-epigallocatechin 3-O-gallate (EGCG) increased by 1556.72%. Table 4 Decrease amount of relative content of alkaloids before and after fermentation

[0096]

[0097]

[0098] Table 5 Increase amount of relative content of flavonoids before and after fermentation

[0099]

[0100] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A Lentilactobacillus buchneri GM3, characterized in that, Deposited with the Guangdong Microbial Culture Collection Center on January 9, 2025, with the deposit number GDMCC No: 65737.

2. A bacterial agent, characterized in that, Containing Lactobacillus brueckii GM3 described in claim 1.

3. Use of Lactobacillus brueckii GM3 described in claim 1 or the bacterial agent described in claim 2 in the preparation of fruit and vegetable juice.

4. A composition for producing fruit and vegetable juice, characterized in that, Comprising fruits and vegetables and a starter, the starter containing Lactobacillus brueckii GM3 described in claim 1 or the bacterial agent described in claim 2.

5. A method for increasing the contents of γ-aminobutyric acid and flavonoids and decreasing the contents of sugar and alkaloids in fruit and vegetable juices, characterized in that, Fermenting fruit and vegetable juice with a starter containing Lactobacillus brueckii GM3 described in claim 1 or the bacterial agent described in claim 2.

6. A preparation method of a nutritious and healthy fermented fruit and vegetable juice, characterized in that, Fermenting fruit and vegetable juice with a starter containing Lactobacillus brueckii GM3 described in claim 1 or the bacterial agent described in claim 2, to obtain.

7. Fermented fruit and vegetable juice prepared by the method according to claim 6.

8. Fermented litchi juice prepared by the method according to claim 6.

9. The fermented litchi juice according to claim 8, wherein The content of γ-aminobutyric acid is not less than 1.74 g / L.

10. The fermented litchi juice according to claim 8 or 9, characterized in that, The total sugar content is not higher than 144 mg / mL.

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