Prunus armeniaca product fermented by using casei paracasei FMBL L23249 FJX and preparation method of prunus armeniaca product

Abstract

The invention relates to the technical field of biology, and particularly provides application of lactobacillus paracasei FMBL L23249FJX in fermentation of prunus armeniaca, the lactobacillus paracasei FMBL L23249FJX is preserved in China Center for Type Culture Collection on June 26, 2023, and the preservation number is CCTCC NO: M20231097; in the process of fermenting the prunus armeniaca, the viable count is increased to 3.37 * 10 < 9 > CFU / mL, and the prunus armeniaca has the advantage of stable growth; the total acid content is generally in a rising trend, the pH is generally in a decreasing trend, and the total phenol content is in a trend of first rising and then decreasing; after fermentation is performed for 24 hours, the total phenol content in the apricot and plum juice is increased to 591.265 mg / L and is remarkably increased by 76.77%; the ABTS free radical scavenging rate and the DPPH free radical scavenging rate of the fermented apricot and plum juice are remarkably increased by 24.73% and 91.97% respectively, and the fermented apricot and plum juice can be widely applied to fermentation of the apricot and plum juice and prolong the storage life of apricots and plums.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, specifically to an apricot-plum product fermented using Lactobacillus paracasei FMBL L23249 FJX and its preparation method. Background Technology

[0002] Apricot-plum (Prunus salicina) belongs to the genus Prunus in the family Rosaceae. It is a new fruit variety bred through hybridization of apricot and plum, combining some of the superior traits of both apricot and plum, thus possessing unique appearance, taste, and flavor characteristics. It is rich in vitamins, minerals, and antioxidants. Currently cultivated commercial varieties include Flavor Rose, Wei Di, Dinosaur Egg, Red Velvet, and Black Rose. Xinjiang, due to its unique geographical location and abundant sunshine and heat resources, produces apricot-plums of excellent quality and taste, winning the favor of consumers. Apricot-plums are mainly consumed fresh, but as seasonal fruits, the fresh fruit supply period is short, and apricot-plums are prone to rotting and spoilage, leading to a decline in nutritional quality and difficulties in storage. Many substandard fruits form during ripening and long-term storage. Therefore, maximizing the utilization of substandard fruit and increasing its economic value is crucial for the development of the apricot-plum industry.

[0003] Processing seasonal fruits into preserves, juices, and canned goods is an important way to extend their shelf life and increase their economic value. Existing apricot and plum juices are prepared through pressing, filtering, and blending, which suffers from problems such as a monotonous taste, significant loss of nutrients, and a short shelf life. Furthermore, without precise formulas and suitable blending techniques, it is difficult to create a juice flavor that meets market demands and target consumer taste preferences, potentially resulting in juices that are too sour, too sweet, or bland. If the sugars, acids, and flavorings added during blending are not completely and evenly dissolved, it can cause uneven concentrations of components in the juice, affecting the consistency of taste and even leading to sedimentation.

[0004] With consumers increasingly focused on health and nutrition, the demand for functional foods and beverages is growing. In this context, fermented foods have gained widespread attention due to their unique health benefits. Fermented foods not only provide rich nutrients but also produce various bioactive substances through the metabolic activities of microorganisms, which have positive effects on human health. Probiotic fermentation is an effective food processing technology that utilizes the metabolic activities of probiotics to improve the sensory properties of food, enhance its nutritional value, and impart new health benefits.

[0005] In their previous research, the inventor's research group screened a strain of Lacticaseibacillus paracasei FMBL L23249 FJX from the feces of healthy individuals. The study found that it could efficiently utilize chickpea extract to achieve rapid proliferation. The viable count of *Lactobacillus paracasei* FMBL L23249 FJX reached 9.17 ± 0.01 lg (CFU / mL) after 12 hours of fermentation. After storage at 4℃ for 21 days, the viable count of *Lactobacillus paracasei* FMBL L23249 FJX in chickpea extract remained above 8.32 ± 0.03 lg (CFU / mL), making it suitable for preparing chickpea yogurt. The inventors applied for an invention patent for a strain of *Lactobacillus paracasei* FMBL L23249 FJX suitable for chickpea fermentation and its application (CN117535185B). Based on previous research, it was discovered that it can adsorb heavy metals lead and cadmium, and an invention patent was applied for for a composite bacterial agent with synergistic enhancement of heavy metal adsorption capacity and its microcapsule preparation and application (CN118909872A). Based on the above research, this invention unexpectedly discovered that Lactobacillus paracasei FMBLL23249FJX can also ferment apricots and plums, improving the flavor of apricot and plum juice, enhancing its nutritional value, and giving it new health benefits. Summary of the Invention

[0006] The primary objective of this invention is to provide the application of Lacticaseibacillus paracasei FMBL L23249 FJX in fermented apricots and plums. The Lacticaseibacillus paracasei FMBL L23249 FJX was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M 20231097.

[0007] The second objective of this invention is to provide an apricot-plum product obtained by fermentation of *Lactobacillus paracasei* FMBL L23249 FJX, which was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M 20231097.

[0008] Preferably, the product is one or more of the following: liquid beverage, solid beverage, fermented milk, or freeze-dried powder.

[0009] The third objective of this invention is to provide an apricot-plum liquid beverage with a significantly increased total phenol content. The apricot-plum liquid beverage is obtained by fermentation of *Lactobacillus paracasei* FMBL L23249 FJX, which was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M20231097.

[0010] The fourth objective of this invention is to provide a method for preparing the apricot-plum liquid beverage, characterized by comprising the following steps:

[0011] (1) Weigh out the apricot and plum fruits, wash them, drain them and set them aside;

[0012] (2) Add the apricot and plum fruits obtained in step (1) to distilled water, blend into a pulp, filter, add 3% to 7% w / v glucose and 0.3% to 1.5% w / v casein to mix, stir evenly, and obtain apricot and plum juice;

[0013] (3) Place the apricot and plum juice obtained in step (2) at 95°C for 10 minutes to sterilize. After cooling to room temperature, place it in a refrigerator at 4°C for later use.

[0014] (4) Place the Lactobacillus paracasei FMBL L23249 FJX bacterial suspension on MRS solid medium for anaerobic culture to activate it, and then pick a single colony for subculture in MRS liquid medium.

[0015] (5) Take the second-generation bacterial culture obtained in step (4), centrifuge, discard the supernatant, wash the precipitate with 0.9% physiological saline, centrifuge again, and resuspend in physiological saline to achieve a bacterial density of 1.0 × 10⁻⁶. 7 CFU / mL; inoculate it into the apricot and plum juice obtained in step (3), let it stand and culture to obtain fermented apricot and plum liquid beverage.

[0016] Preferably, in step (2), the amount of glucose added is 4% to 6%, and the amount of casein added is 0.3% to 0.9%.

[0017] Preferably, the filtration in step (2) uses 100-300 mesh gauze.

[0018] Preferably, the fermentation time in step (5) is 0h to 48h.

[0019] Preferably, the fermentation time in step (5) is 12h-24h.

[0020] The beneficial effects of this invention are: This invention provides the application of *Lactobacillus paracasei* FMBL L23249 FJX in fermented apricot and plum juice. During the fermentation process of apricot and plum juice, *Lactobacillus plantarum* FMBL L23249 showed good growth, increasing from an initial 8.0 × 10⁻⁶. 6 CFU / mL increased to 3.37 × 10⁻⁶ 9 The fermentation process of apricot and plum juice, with a concentration of CFU / mL, exhibits stable growth. During the 0-48h fermentation period, the total acid content of the apricot and plum juice generally increased, while the pH generally decreased, and the total phenol content initially increased and then decreased. At 24h of fermentation, the total phenol content in the apricot and plum juice increased from the initial 334.475 mg / L to 591.265 mg / L, an increase of 76.77%, significantly higher than the pre-fermentation total phenol content. This significantly improved the antioxidant activity of the apricot and plum juice, with the ABTS free radical scavenging rate of fermented apricot and plum juice increasing by 24.73% compared to before fermentation. The DPPH free radical scavenging rate of fermented apricot and plum juice also increased by 91.97% compared to before fermentation. This method can be widely applied to the fermentation of apricot and plum juice, extending the shelf life of apricots and plums. Attached Figure Description

[0021] Figure 1 Effect of different inoculum sizes on polyphenol content in fermented apricot and plum juice

[0022] Figure 2 Changes in viable cell count of Lactobacillus paracasei FMBL L23249 FJX during fermentation of apricot and plum juice

[0023] Figure 3 Changes in total acid and pH during fermentation of apricot and plum juice using Lactobacillus paracasei FMBL L23249 FJX

[0024] Figure 4 Changes in total phenolic content during fermentation of apricot and plum juice by Lactobacillus paracasei FMBL L23249 FJX

[0025] Figure 5 Changes in ABTS and DPPH free radical scavenging rates during fermentation of apricot and plum juice by Lactobacillus paracasei FMBL L23249 FJX Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the specific implementation methods of the present invention are described in detail below through several embodiments, thereby providing a clear and complete description of the present invention, but without limiting the scope of the claims of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all conventional products that can be purchased commercially.

[0027] In the following examples, the MRS agar medium formulation is as follows: 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 1mL Tween 80, 2g K2HPO4, 5g sodium acetate, 2g diammonium citrate, 0.58g MgSO4·7H2O, 0.25g MnSO4·7H2O, 0.5g L-cysteine ​​hydrochloride, 20mg vancomycin, 20g agar, 1000mL water, sterilized at 115℃ for 20min.

[0028] The apricots and plums in the following implementation case were purchased in Kashgar, Xinjiang.

[0029] Unless otherwise specified, other experimental materials and instruments can be purchased commercially.

[0030] The *Lactaseibacillus paracasei* FMBL L23249FJX described in this invention was deposited on June 26, 2023, at the China Center for Type Culture Collection (CCTCC), accession number CCTCC NO: M 20231097, located at Wuhan University, Wuhan, China, telephone: 027-68754052; fax: 027-68754833. Invention patents CN117535185B and CN118909872A have been applied for. This invention is based on previous research, focusing on fermented foods and health products, and represents subsequent research and patent applications.

[0031] In the following examples, Lacticaseibacillus paracasei FMBL L23249FJX is abbreviated as Lacticaseibacillus paracasei FMBL L23249 FJX.

[0032] Example 1: Preparation of Fermented Apricot and Plum Juice

[0033] The preparation method of apricot and plum juice is as follows:

[0034] (1) Weigh 100g of apricot and plum fruits, ensuring that they are free from pests, diseases and mechanical damage, and repeatedly rinse them with running water to wash away the mud and impurities on the surface, then drain them for later use.

[0035] (2) Add the washed apricot and plum fruits to 300mL of distilled water and blend them into a homogenate using a high-speed blender (5min). After filtering the resulting apricot and plum fruit pulp through 300-mesh gauze, add glucose and casein to adjust the mixture and stir evenly to obtain apricot and plum juice.

[0036] (3) Place the apricot and plum juice from (2) above at 95°C for 10 minutes to sterilize. After cooling to room temperature, place it in a 4°C refrigerator for later use.

[0037] (4) The Lactobacillus paracasei FMBL L23249 FJX bacterial culture stored in glycerol tubes was streaked on MRS solid medium for activation, and then passaged twice in liquid medium for 12 hours each time, with an inoculum of 2%.

[0038] (5) Take the second-generation bacterial culture, centrifuge at 8000 rpm for 3 min, discard the supernatant, wash the precipitate with 0.9% physiological saline, centrifuge, repeat 3 times, resuspend in physiological saline to achieve a bacterial density of 1.0 × 10⁻⁶. 7 CFU / mL was inoculated into the sterilized apricot and plum juice in (3), and cultured at 37°C to obtain fermented apricot and plum juice.

[0039] Example 2: Optimization of substrate ratio for fermented apricot and plum juice

[0040] Glucose and casein were used as supplementary carbon and nitrogen sources, respectively, and their supplementation amounts were optimized. A two-factor, five-level orthogonal experiment was designed to determine the optimal addition amounts of carbon and nitrogen sources in the fermentation substrate. The substrate was inoculated with 3% (v / v) *Lactobacillus paracasei* FMBL L23249FJX, fermented at 37°C for 24 h, and then allowed to stand at 4°C for 2 h to stop fermentation. The viable cell count was used as an indicator to determine the optimal addition amounts of carbon and nitrogen sources.

[0041] As shown in Table 1, comparing the viable cell counts, when the carbon and nitrogen source supplementation levels were low, the viable cell count increased with increasing supplementation levels, and there were significant differences among the groups (p < 0.05). When the glucose addition reached 5%–6%, the viable cell count peaked; further increasing the carbon source supplementation to 7% did not significantly alter the viable cell count. When the nitrogen source supplementation reached above 1.2%, casein could not be completely dissolved, leading to clumping and layering in the apricot and plum juice after fermentation. Therefore, based on the viable cell count results, the optimal ratio was determined to be 5% carbon source supplementation and 0.9% nitrogen source supplementation, at which point the viable cell count reached 2.863 × 10⁻⁶. 9 cfu / mL or higher.

[0042] Table 1 Results of viable cell count detection after substrate ratio optimization

[0043]

[0044] Note: a,b,c,d,e This indicates a significant difference between peer groups (p < 0.05). A,B,C,D,E This indicates a significant difference between groups within the same column (p < 0.05).

[0045] Example 3: Optimization of inoculum size for fermented apricot and plum juice strains

[0046] After the substrate was optimized, the juice samples were supplemented with 5% (w / v) glucose and 0.9% (w / v) casein, and then inoculated with *Lactobacillus paracasei* FMBL L23249 FJX at inoculation rates of 1%, 2%, 3%, 4%, and 5% (v / v), respectively. The samples were then fermented at 37°C for 24 hours, and the total phenol content was used as an indicator to determine the optimal inoculation rate.

[0047] like Figure 1 As shown, fermentation significantly increases the polyphenol content in fermented fruit juice (P<0.05). Furthermore, with increasing inoculum size, the total phenol content initially increases and then decreases, reaching its maximum at an inoculum size of 3%, with a total phenol content of 589.599 mg / L. Therefore, an inoculum size of 3% is selected as the optimal parameter.

[0048] Example 4: Determination of the growth performance of bacterial strains in fermented apricot and plum juice

[0049] (1) The prepared apricot and plum juice was placed in a constant temperature incubator at 37℃ for fermentation. Samples were taken from the apricot and plum juice at 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, and 48h for viable cell counting.

[0050] (2) Referring to GB4789.35-2016 "Microbiological Examination of Food - Examination of Lactic Acid Bacteria", the plate dilution method was used. 1 mL of fermented fruit juice was diluted to 10... -5 10 -6 10 -7 Spread the bacteria evenly on MRS agar and incubate anaerobically at 37°C for 48 hours. Take plates with colony counts of 30-300 CFU and count them. Repeat each group three times.

[0051] Changes in viable counts of *Lactobacillus paracasei* FMBL L23249 FJX in apricot and plum juice are as follows: Figure 2 As shown, viable cell counts revealed that the total bacterial count of apricot and plum juice fermented by *Lactobacillus paracasei* FMBL L23249 FJX generally increased during the 0-48 h culture period at 37℃. Furthermore, *Lactobacillus paracasei* FMBL L23249 FJX exhibited good growth during fermentation, increasing from an initial 8.0 × 10⁻⁶. 6 CFU / mL increased to 3.37 × 10⁻⁶ 9 CFU / mL. It is well known in the art that strains used for fermenting fruit juices need to have a growth capacity of at least 10 CFU / mL in fruit juice. 8Only when the concentration of CFU / mL is reached is it worthwhile to develop a product. The *Lactobacillus paracasei* FMBL L23249 FJX described therein has a growth capacity of 3.37 × 10⁻⁶ CFU / mL. 9 With a concentration of CFU / mL, it shows promise for developing apricot and plum juice products.

[0052] Example 5: Changes in pH and titratable acidity during fermentation of apricot and plum juice by *Lactobacillus paracasei* FMBL L23249 FJX

[0053] (1) The prepared apricot and plum juice was placed in a constant temperature incubator at 37℃ for fermentation. Samples were taken from the apricot and plum juice at 0h, 6h, 12h, 18h, 24h, 30h, 36h, 42h and 48h of fermentation to determine the pH value and titratable acidity.

[0054] (2) The pH value was measured using a PHS-3C pH meter, and each group was repeated 3 times.

[0055] (3) Dilute 1 mL of apricot and plum juice with 20 mL of deionized water, and titrate with 0.1 mol / L sodium hydroxide solution. Stir the solution until the pH stabilizes at 8.2 ± 0.1. The calculation formula is:

[0056]

[0057] In the formula, V1: volume of sodium hydroxide solution consumed, mL; V2: volume of apricot and plum juice, mL; C NaOH : Concentration of sodium hydroxide, mol / L, content expressed as malic acid (k = 0.067).

[0058] The acid production curve of Lactobacillus paracasei FMBL L23249 FJX during fermentation of apricot and plum juice is as follows: Figure 3 As shown, the total acid content of apricot and plum juice generally increased during the fermentation process from 0 to 48 hours, while the pH generally decreased. In the early stages of fermentation, lactic acid bacteria metabolized lactose to produce lactic acid, increasing the total acid content of the juice and lowering its pH. The production of lactic acid made the environment acidic, and the fermentation produced a suitable amount of CO2, both of which inhibited the growth of other microorganisms, thus acting as a preservative. After 48 hours of fermentation, the pH of the apricot and plum juice decreased to 3.93, but *Lactobacillus paracasei* FMBL L23249 FJX could still survive, indicating its strong acid resistance. Combining the growth of the strain and the changes in the total acid content and pH of the juice during fermentation, it can be seen that the optimal fermentation time for *Lactobacillus paracasei* FMBL L23249 FJX in apricot and plum juice is 24 hours.

[0059] Example 6: Changes in total phenolic content during fermentation of apricot and plum juice by *Lactobacillus paracasei* FMBLL23249 FJX

[0060] 1. The prepared apricot and plum juice was placed in a constant temperature incubator at 37℃ for fermentation. 1 mL samples were taken from the apricot and plum juice at 0h, 6h, 12h, 18h, 24h, 30h, 36h, 42h, and 48h of fermentation to determine the total phenol content.

[0061] 2. The total phenol content in the sample was determined using the Folin-Ciocalteu method.

[0062] (1) Take fermented apricot and plum juice from different fermentation stages, dilute it 10 times with distilled water, and prepare sample test solution.

[0063] (2) Take 150 μL of sample test solution and add 150 μL of Folin-Ciocalteu. After vortexing and homogenization, allow the color reaction to proceed for 10 min. Then, add 600 μL of 20% Na2CO3 solution and react in the dark for 20 min. Measure the absorbance at 765 nm. Prepare a gallic acid stock solution with a mass concentration of 200 μg / mL and dilute it to make a series of standard solutions with mass concentrations of 0-200 μg / mL. The linear regression equation is obtained as Y = 0.0108X + 0.0743, R0 2 =0.9992.

[0064] like Figure 4 As shown, during the fermentation of apricot and plum juice by *Lactobacillus paracasei* FMBL L23249 FJX (0-48h), the total phenolic content showed a trend of first increasing and then decreasing. From 0-24h of fermentation, the total phenolic content in the apricot and plum juice gradually increased from the initial 334.475 mg / L, reaching 526.206 mg / L at 12h and 591.265 mg / L at 24h, significantly higher than the pre-fermentation total phenolic content. However, it decreased to 455.20 mg / L in the later stage of fermentation (48h). After 24 hours of fermentation, the total phenolic content in the apricot and plum juice increased by 76.77% compared to before fermentation. This indicates that *Lactobacillus paracasei* FMBL L23249 FJX can significantly increase the polyphenol content in apricot and plum juice after 24h of fermentation, consistent with the optimal fermentation time of 24h obtained in Example 3.

[0065] Example 7: Changes in antioxidant activity of *Lactobacillus paracasei* FMBLL23249 FJX during fermentation of apricot and plum juice.

[0066] (1) The prepared apricot and plum juice was placed in a constant temperature incubator at 37℃ for fermentation. 1 mL of the apricot and plum juice was taken at 0h, 6h, 12h, 18h, 24h, 30h, 36h, 42h and 48h of fermentation to determine the antioxidant activity of the fermented juice.

[0067] (2) Determination of ABTS free radical scavenging ability: A 1:1 mixture of 7.4 mmol / L ABTS solution and 2.6 mmol / L potassium persulfate solution was prepared and reacted in the dark for 12–16 h. The mixture was then diluted with ethanol to achieve an absorbance of 0.70 ± 0.02 at 734 nm, which was used as the ABTS working solution. 40 μL of the sample to be tested was added to 800 μL of the working solution and reacted in the dark for 20 min. The absorbance A of the sample was measured at 734 nm. s The blank group consisted of distilled water containing ABTS, and the control group consisted of distilled water and the sample. The absorbance was measured as A. b and A c .

[0068]

[0069] (3) Determination of DPPH free radical scavenging ability: Prepare 0.025 g / L DPPH solution, take 0.1 mL of fruit juice sample and mix it with 3.9 mL of DPPH solution. React in the dark for 30 min and measure its absorbance value at 515 nm as Bs; In addition, replace the fruit juice with 0.1 mL of anhydrous ethanol, mix it with 3.9 mL of DPPH solution and measure its absorbance as Bc, as a blank control group.

[0070]

[0071] The results of ABTS radical scavenging rate and DPPH radical scavenging rate are as follows: Figure 5 As shown, during the fermentation of apricot and plum juice by *Lactobacillus paracasei* FMBLL23249 FJX (0-48h), both ABTS and DPPH free radical scavenging rates showed a trend of first increasing and then decreasing. At 24h of fermentation, the ABTS free radical scavenging rate reached 95.84%, significantly higher than the unfermented apricot and plum juice (76.84%) by 24.73%; the DPPH free radical scavenging rate reached 59.76%, significantly higher than the unfermented apricot and plum juice (31.13%) by 91.97%. However, at 48h of fermentation, the ABTS free radical scavenging rate decreased to 86.62%, and the DPPH free radical scavenging rate decreased to 46.58%. The results indicate that the apricot and plum juice fermented by *Lactobacillus paracasei* FMBL L23249 FJX described in this invention significantly improved the ABTS and DPPH free radical scavenging rates of apricot and plum juice, suggesting that fermented apricot and plum juice has the potential to become a product with excellent antioxidant activity.

[0072] Example 8: Preparation of Apricot and Plum Solid Beverage

[0073] Administer 1.0 × 10 at a 3% dose. 7Add CFU / mL of *Lactobacillus paracasei* FMBL L23249 FJX to the apricot-plum juice prepared in the above example, ferment at 37°C for 24 hours, then add 3-10% maltodextrin, 0.5-1% trehalose, and 1% galactooligosaccharides. After mixing evenly, freeze-dry or spray-dry to prepare a freeze-dried powder of fermented apricot-plum juice, thus obtaining an apricot-plum solid beverage. It should be noted that any value of maltodextrin and trehalose within the above range can achieve the preparation of a solid beverage.

[0074] In summary, this invention provides the application of *Lactobacillus paracasei* FMBL L23249 FJX in fermented apricot and plum juice. During the fermentation process, *Lactobacillus plantarum* FMBL L23249 showed good growth, increasing from an initial 8.0 × 10⁻⁶. 6 CFU / mL increased to 3.37 × 10⁻⁶ 9 The fermentation process of apricot and plum juice, with a concentration of CFU / mL, exhibits stable growth. During the 0-48h fermentation period, the total acid content of the apricot and plum juice generally increased, while the pH generally decreased, and the total phenol content initially increased and then decreased. At 24h of fermentation, the total phenol content in the apricot and plum juice increased from the initial 334.475 mg / L to 591.265 mg / L, an increase of 76.77%, significantly higher than the pre-fermentation total phenol content. This significantly improved the antioxidant activity of the apricot and plum juice, with the ABTS free radical scavenging rate of fermented apricot and plum juice increasing by 24.73% compared to before fermentation. The DPPH free radical scavenging rate of fermented apricot and plum juice also increased by 91.97% compared to before fermentation. This method can be widely applied to the fermentation of apricot and plum juice, extending the shelf life of apricots and plums.

Claims

1. The application of *Lactaseibacillus paracasei* FMBL L23249 FJX in fermented apricots and plums, characterized in that... The *Lactobacillus paracasei* FMBL L23249 FJX was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M 20231097.

2. An apricot-plum product, characterized in that, The apricot and plum product is obtained by fermentation of Lactobacillus paracasei FMBL L23249 FJX, which was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M 20231097.

3. The apricot and plum product as described in claim 2, characterized in that, The product is one or more of the following: liquid beverage, solid beverage, fermented milk, or freeze-dried powder.

4. An apricot-plum liquid beverage with significantly increased total phenolic content, characterized in that, The apricot-plum liquid beverage is obtained by fermentation of Lactobacillus paracasei FMBL L23249 FJX, which was deposited at the China Center for Type Culture Collection on June 26, 2023, with accession number CCTCC NO: M 20231097.

5. The method for preparing apricot-plum liquid beverage as described in claim 4, characterized in that, Includes the following steps: (1) Weigh out the apricot and plum fruits, wash them, drain them and set them aside; (2) Add the apricot and plum fruits obtained in step (1) to distilled water, blend into a pulp, filter, add 3% to 7% w / v glucose and 0.3% to 1.5% w / v casein to mix, stir evenly, and obtain apricot and plum juice; (3) Place the apricot and plum juice obtained in step (2) at 95°C for 10 minutes to sterilize. After cooling to room temperature, place it in a refrigerator at 4°C for later use. (4) Place the Lactobacillus paracasei FMBL L23249 FJX bacterial suspension on MRS solid medium for anaerobic culture to activate it, and then pick a single colony for subculture in MRS liquid medium. (5) Take the second-generation bacterial culture obtained in step (4), centrifuge, discard the supernatant, wash the precipitate with 0.9% physiological saline, centrifuge again, and resuspend in physiological saline to achieve a bacterial density of 1.0 × 10⁻⁶. 7 CFU / mL; inoculate it into the apricot and plum juice obtained in step (3), let it stand and culture to obtain fermented apricot and plum liquid beverage.

6. The preparation method according to claim 5, characterized in that, In step (2), the amount of glucose added is 4% to 6%, and the amount of casein added is 0.3% to 0.9%.

7. The preparation method according to claim 5, characterized in that, The filtration in step (2) uses 100-300 mesh gauze.

8. The preparation method according to claim 5, characterized in that, The fermentation time in step (5) is 0h to 48h.

9. The preparation method according to claim 8, characterized in that, The fermentation time in step (5) is 12h-24h.

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