Application of lactobacillus rhamnosus FMBL L23004 CNN in fermentation of prunus salicina and prunus salicina product prepared from lactobacillus rhamnosus FMBL L23004 CNN

Abstract

The invention relates to the technical field of biology, in particular to application of lactobacillus rhamnosus FMBL L23004CNN in fermentation of plums, and the preservation number of the lactobacillus rhamnosus FMBL L23004CNN is CCTCC (China Center for Type Culture Collection) NO: M 20231099. In the process of fermenting the prunus armeniaca, the viable count is increased to 5.10 * 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 563.436 mg / L and is remarkably increased by 68.45%; aBTS and DPPH free radical scavenging rates of the fermented apricot and plum juice are remarkably improved; the inhibition rate on alpha-amylase and alpha-glucosidase is obviously improved; the method can be widely applied to fermentation of apricot and plum juice and prolongs the storage life.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to application of Lactobacillus rhamnosus FMBL L23004 CNN in fermenting apricots and plums and prepared apricot and plum products. Background Art

[0002] The apricot plum (Prunus salicina) belongs to the genus Prunus in the Rosaceae family. It is a new fruit variety bred by hybridizing an apricot and a plum. It combines some of the beneficial traits of both, resulting in a unique appearance, texture, and flavor. 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 sunlight and heat resources, produces apricot plums of superior quality and excellent taste, which have won widespread consumer favor.

[0003] Apricot and plum flesh has a high water content, generally exceeding 80%, and is rich in nutrients such as sugar and protein. This makes it susceptible to microbial contamination such as bacteria and mold during storage, leading to rot and deterioration. The relatively thin peel of apricot and plum allows for easy loss of moisture into the air through the pores and cuticle on the surface. Over time, this causes the fruit to shrink and become dry and astringent, seriously affecting its quality. Furthermore, apricot and plum fruit release large amounts of ethylene gas during ripening, which can cause them to soften and overripen quickly, shortening their shelf life.

[0004] At present, the storage methods of apricots and plums include fresh fruit storage and storage after preparation into finished products. Fresh fruit storage mainly relies on low-temperature storage, such as refrigerated storage, ice cellar storage, etc. However, the above storage methods have the problems of high cost, high energy consumption, inflexible space utilization and difficult temperature control. The finished products prepared include jams, dried fruits, juices and canned fruits, etc., in order to increase their economic benefits. However, there are still many difficult-to-solve technical problems in the preparation process of the above finished products. For example, the existing apricot and plum juice is prepared by squeezing, filtering, blending and other processes, which have problems such as single taste, serious loss of nutrients and short shelf life. And without a precise formula and a suitable blending process, it is difficult to adjust the juice flavor that meets market demand and the taste preferences of target consumers, which may lead to problems such as the juice being too sour, too sweet or bland. If the sugar, acid, essence and other substances added during the blending process cannot be completely dissolved evenly, it will cause uneven concentration of local components of the juice, affect the consistency of taste, and even cause precipitation and other phenomena.

[0005] As consumers increasingly prioritize health and nutrition, demand for functional foods and beverages continues to grow. Within this trend, fermented foods are attracting widespread attention for their unique health benefits. Fermented foods not only provide a wealth of nutrients but also produce a variety of bioactive substances through microbial metabolic activity, which have positive effects on human health.

[0006] The inventor's research group has long been engaged in research in the field of probiotics. In previous studies, a strain of Lactobacillus paracasei FMBLL23004 CNN was screened from the feces of healthy people. It not only has good antibacterial effects on enteropathogenic Escherichia coli, enterotoxigenic Escherichia coli, Salmonella enterica subspecies typhimurium, enterohemorrhagic Escherichia coli, Listeria monocytogenes, and Salmonella enterica subspecies, but also has acid and bile salt resistance, a high survival rate in gastric and intestinal juices, and good self-aggregation and hydrophobicity as well as the ability to utilize carbohydrates (see CN117660253B); it can be used to prepare drugs or food additives that inhibit pathogenic bacteria; it was then combined with Lactobacillus plantarum FMBL L23036CNN was compounded to produce a composite bacterial agent with antibacterial properties, which has the effect of preventing and treating diarrhea (see CN117683671B). Based on the above research, the present invention unexpectedly discovered that Lactobacillus rhamnosus FMBL L23004 CNN can also ferment apricots and plums, improving the flavor and nutritional value of apricot and plum juice, and imparting new health benefits. Summary of the Invention

[0007] The primary purpose of the present invention is to provide an application of Lactobacillus paracasei FMBL L23004CNN in fermenting apricot plums. The Lactobacillus paracasei FMBL L23004CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

[0008] A second object of the present invention is to provide an apricot and plum product, which is obtained by fermenting apricot and plum or apricot and plum products with rhamnosus lactobacillus FMBL L23004 CNN. The rhamnosus lactobacillus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

[0009] Preferably, the product is one or more of a liquid beverage, a solid beverage, fermented milk or a freeze-dried powder.

[0010] The third object of the present invention is to provide an apricot and plum liquid beverage with significantly improved total phenol content, wherein the apricot and plum liquid beverage is fermented by rhamnosus casei bacteria FMBL L23004 CNN, and the rhamnosus casei bacteria FMBL L23004CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a preservation number of CCTCC NO: M20231099.

[0011] A fourth object of the present invention is to provide a method for preparing the apricot-plum liquid beverage, which is characterized by comprising the following steps:

[0012] (1) Weigh apricot and plum fruits, wash them, drain them and set aside;

[0013] (2) adding distilled water to the apricot and plum fruits obtained in step (1), beating into pulp, filtering, adding 3% to 7% w / v glucose and 0.3% to 1.5% w / v casein, and stirring evenly to obtain apricot and plum juice;

[0014] (3) The apricot and plum juice obtained in step (2) was placed at 95°C for sterilization for 10 minutes, and after cooling to room temperature, placed in a refrigerator at 4°C for later use;

[0015] (4) The Lactobacillus rhamnosus FMBL L23004 CNN bacterial solution was placed on MRS solid medium for anaerobism culture, activated, and a single colony was picked and subcultured in MRS liquid medium;

[0016] (5) Take the second generation bacterial solution obtained in step (4), centrifuge it, remove the supernatant, wash the precipitate with 0.9% saline, centrifuge it, and resuspend it with saline to make the bacterial density reach 1.0×10 7 CFU / mL; inoculate it into the apricot and plum juice obtained in step (3), culture it statically, and obtain a fermented apricot and plum liquid beverage.

[0017] 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%.

[0018] Preferably, the filtration in step (2) uses gauze with a mesh size of 100 to 300.

[0019] Preferably, the fermentation time in step (5) is 0 h to 48 h.

[0020] Preferably, the fermentation time in step (5) is 12h-24h.

[0021] The fifth object of the present invention is to provide an application of fermenting apricots and plums with Lactobacillus paracasei FMBL L23004CNN in the preparation of antioxidant products. The Lactobacillus paracasei FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M20231099.

[0022] The sixth object of the present invention is to provide the use of Lacticaseibacillus paracasei FMBL L23004CNN fermenting apricot plum in inhibiting α-glucosidase activity or preparing α-glucosidase inhibitors, wherein the Lactobacillus paracasei FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

[0023] The seventh object of the present invention is to provide the use of Lacticaseibacillus paracasei FMBL L23004CNN fermenting apricot plum in inhibiting dipeptidyl peptidase IV activity or preparing a dipeptidyl peptidase IV inhibitor, wherein the Lactobacillus paracasei FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

[0024] An eighth object of the present invention is to provide an application of fermenting apricot plum with rhamnosus Lactobacillus paracasei FMBL L23004CNN in the preparation of a hypoglycemic product, characterized in that the rhamnosus Lactobacillus paracasei FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCCNO: M 20231099.

[0025] The beneficial effects of the present invention are as follows: the present invention provides an application of Lactobacillus rhamnosus FMBL L23004 CNN in fermenting apricot plums to prepare apricot plum products. In the process of fermenting apricot plum juice, the growth of Lactobacillus plantarum FMBL L23249 is good, from the initial 1.01×10 7 The CFU / mL increased to 5.10×10 9CFU / mL, with the advantage of stable growth; during the fermentation process of apricot and plum juice from 0 to 48 hours, the total acid content generally showed an upward trend, the pH generally showed a downward trend, and the total phenol content showed a trend of first increasing and then decreasing; after 24 hours of fermentation, the total phenol content in the apricot and plum juice increased from the initial 334.475 mg / L to 563.436 mg / L, a significant increase of 68.45%; the ABTS and DPPH free radical scavenging rates of the fermented apricot and plum juice increased by 21.69% and 72.95% respectively compared with those before fermentation; and the inhibition rates of α-amylase and α-glucosidase increased by 43.35% and 76.03% respectively compared with unfermented apricot and plum juice. The rhamnosus casei bacteria FMBL L23004 CNN of the present invention can be widely used in the fermentation of apricot and plum juice to extend the shelf life of apricots and plums. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Effects of different inoculum amounts on polyphenol content in fermented apricot and plum juice

[0027] Figure 2 Changes in viable cell count during fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN

[0028] Figure 3 Changes of total acid and pH during fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN

[0029] Figure 4 Changes of total phenolic content during fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN

[0030] Figure 5 Changes in ABTS and DPPH free radical scavenging rates during fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the specific embodiments of the present invention are described in detail below through several examples to clearly and completely describe the present invention, but no limitation is imposed on the claims of the present invention. Specific conditions are not specified in the examples, and the experiments were carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased through commercial channels.

[0032] In the following examples, the MRS agar medium formula is as follows: peptone 10 g, beef extract 10 g, yeast extract 5 g, glucose 20 g, Tween 80 1 mL, K2HPO4 2 g, sodium acetate 5 g, diammonium citrate 2 g, MgSO4·7H2O 0.58 g, MnSO4·7H2O 0.25 g, L-cysteine ​​hydrochloride 0.5 g, vancomycin 20 mg, agar 20 g, water 1000 mL, and sterilized at 115°C for 20 min.

[0033] The apricots and plums used in the following implementation cases were purchased in Kashgar, Xinjiang.

[0034] Unless otherwise specified, other experimental materials and instruments can be purchased through commercial channels.

[0035] The Lactobacillus paracasei strain FMBL L23004CNN described in this invention was deposited with the China Center for Type Culture Collection on June 26, 2023, under the CCTCC No. M 20231099. The deposit address is Wuhan University, Wuhan, China. Tel: 027-68754052; Fax: 027-68754833. Patents CN117535185B and CN118909872A have been applied for. This invention is the result of subsequent research and patent layout on the basis of previous research, focusing on fermented foods and health products.

[0036] In the following examples, Lacticaseibacillus paracasei FMBL L23004CNN is abbreviated as Lactobacillus paracasei FMBL L23004 CNN.

[0037] Example 1: Preparation of fermented apricot and plum juice

[0038] The preparation method of apricot and plum juice is as follows:

[0039] (1) Weigh 100 g of apricot and plum fruits, ensure they are free of pests and diseases and mechanical damage, rinse repeatedly with running water to clean the surface mud and impurities, and drain for later use;

[0040] (2) Add 300 mL of distilled water to the washed apricot and plum fruits, and blend them into a homogenous slurry using a wall-breaking machine (5 min). The resulting apricot and plum slurry is filtered through 300-mesh gauze, and glucose and casein are added to the mixture and stirred evenly to obtain apricot and plum juice.

[0041] (3) Sterilize the apricot and plum juice prepared in (2) at 95°C for 10 minutes, cool to room temperature, and then refrigerate at 4°C for later use.

[0042] (4) The Lactobacillus rhamnosus FMBL L23004 CNN culture stored in a glycerol tube was streaked onto MRS solid medium for activation, and then passaged twice in liquid medium, each time for 12 hours, with an inoculum size of 2%;

[0043] (5) Take the second generation bacterial solution, centrifuge it at 8000 rpm for 3 min, remove the supernatant, wash the precipitate with 0.9% saline, centrifuge it, repeat three times, and resuspend it with saline to make the bacterial density reach 1.0×10 7 CFU / mL, and inoculated into the sterilized apricot and plum juice in (3), and cultured at 37°C to obtain fermented apricot and plum juice.

[0044] Example 2: Optimization of substrate ratio for fermentation of apricot and plum juice

[0045] Glucose and casein were used as supplemental carbon and nitrogen sources, and their supplementation levels were optimized. A two-factor, five-level orthogonal experiment was designed to optimize the carbon and nitrogen source addition levels in the fermentation medium. The culture was inoculated with 3% (v / v) Lactobacillus rhamnosus FMBL L23004CNN. After fermentation at 37°C for 24 hours, the culture was allowed to stand at 4°C for 2 hours to stop the fermentation. The samples were then tested using viable cell counts to determine the optimal carbon and nitrogen source addition levels.

[0046] As shown in Table 1, from the comparison of the number of viable bacteria, when the amount of carbon source and nitrogen source supplemented is low, the number of viable bacteria increases with the increase of supplementation, and there are significant differences between the groups (p < 0.05). When the amount of glucose added reaches 5% to 6%, the number of viable bacteria reaches a peak. When the amount of carbon source supplemented continues to increase to 7%, the number of viable bacteria remains at a similar level. When the nitrogen source supplement reaches more than 1.2%, casein can no longer be completely dissolved. After fermentation, the texture of the apricot and plum juice will appear abnormal conditions such as agglomeration and stratification. Therefore, through the results of viable bacteria counting, the optimal ratio was finally confirmed: 5% carbon source supplementation and 0.9% nitrogen source supplementation. At this time, the number of viable bacteria can reach 4.50×10 9 cfu / mL or above.

[0047] Table 1 Results of viable bacterial count detection based on optimized matrix ratio

[0048]

[0049] Note: a,b,c,d,e Indicates that there is a significant difference between the same groups (p < 0.05). A,B,C,D,E Indicates that there is a significant difference between the same groups (p < 0.05)

[0050] Example 3: Optimization of the inoculum amount of the strain in the fermentation of apricot and plum juice

[0051] The juice samples after matrix optimization were supplemented with 5% (w / v) glucose and 0.9% (w / v) casein and inoculated with Lactobacillus rhamnosus FMBL L23004 CNN at inoculum sizes of 1%, 2%, 3%, 4%, and 5% (v / v), respectively. The samples were then fermented at 37°C for 24 h. The total phenolic content was used as an indicator to detect the optimal inoculum size.

[0052] like Figure 1 As shown in the results, fermentation significantly increased the polyphenol content in the fermented juice (P < 0.05). Furthermore, with increasing inoculum size, the total phenol content first increased and then decreased, reaching a maximum of 558.137 mg / L at an inoculum size of 3%. Therefore, a 3% inoculum size was selected as the optimal inoculum size parameter.

[0053] Example 4: Determination of bacterial strain growth performance in fermented apricot and plum juice

[0054] (1) The prepared apricot and plum juice was placed in a constant temperature incubator at 37°C for fermentation. Samples were taken from the apricot and plum juice at 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h, 36 h, 38 h, 40 h, 42 h, 44 h, 46 h, and 48 h of fermentation for viable bacterial count.

[0055] (2) Refer to GB4789.35-2016 "Food Microbiology Test for Lactic Acid Bacteria" and use the plate dilution method. Dilute 1 mL of fermented juice to 10 -5 , 10 -6 , 10 -7 , spread evenly on MRS agar, culture anaerobically at 37℃ for 48h, take the plate with 30CFU~300CFU to count, and repeat 3 times for each group.

[0056] The changes of viable bacterial count of Lactobacillus rhamnosus FMBL L23004 CNN in apricot and plum juice Figure 2 As shown in the figure, the total amount of bacteria in the apricot-plum juice fermented by Lactobacillus rhamnosus FMBL L23004 CNN showed an overall upward trend during the 0-48h culture at 37℃, and the growth of Lactobacillus rhamnosus FMBL L23004 CNN was good during the fermentation process, from the initial 1.01×10 7 The CFU / mL increased to 5.10×10 9 CFU / mL. It is well known in the art that the strains used to ferment juice need to have the ability to grow in juice up to 10 8CFU / mL, only then is it worth developing a product. The growth capacity of the Lactobacillus rhamnosus FMBL L23004 CNN is 5.10×10 9 CFU / mL, which has the prospect of developing apricot and plum juice products.

[0057] Example 5: Changes in pH and Total Acidity during Fermentation of Apricot and Plum Juice by Lactobacillus rhamnosus FMBLL23004 CNN

[0058] (1) The prepared apricot and plum juice was placed in a constant temperature incubator at 37°C for fermentation. Samples were taken from the apricot and plum juice at 0 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, and 48 h of fermentation to determine pH and total acid.

[0059] (2) The pH value was measured using a PHS-3C pH acidity meter, with each group repeated three times.

[0060] (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:

[0061]

[0062] Where 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).

[0063] Acid production during fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN Figure 3 As shown, the total acid content of apricot and plum juice generally showed an upward trend, while the pH generally showed a downward trend during the fermentation process from 0 to 48 hours. In the early stages of fermentation, lactic acid bacteria metabolize lactose to produce lactic acid, increasing the total acid content of the juice and lowering its pH. The production of lactic acid acid acidifies the environment, and fermentation produces a moderate amount of CO2, both of which inhibit the growth of other microorganisms and act as a preservative. After 48 hours of fermentation, the pH of the apricot and plum juice dropped to 3.82, but Lactobacillus rhamnosus FMBL L23004 CNN remained viable, demonstrating its strong acid tolerance. Combining the growth of the strain and the changes in the total acid content and pH of the juice during fermentation, it is clear that the optimal fermentation time for apricot and plum juice with Lactobacillus rhamnosus FMBL L23004 CNN is 24 hours.

[0064] Example 6: Changes in Total Phenolic Content During Fermentation of Apricot and Plum Juice by Lactobacillus rhamnosus FMBLL23004 CNN

[0065] 1. The prepared apricot and plum juice was placed in a constant temperature incubator at 37°C for fermentation. 1 mL of sample was taken from the apricot and plum juice at 0 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, and 48 h of fermentation for determination of total phenol content.

[0066] 2. Determination of total phenol content in samples using the Folin-phenol method

[0067] (1) Fermented apricot and plum juices at different fermentation stages were diluted 10 times with distilled water to prepare sample test solutions.

[0068] (2) Take 150 μL of sample test solution and add 150 μL of forlin phenol. After vortexing, color reaction is carried out for 10 minutes. Then, 600 μL of 20% Na2CO3 solution is added and reacted in the dark for 20 minutes. The absorbance is measured at a wavelength of 765 nm. Prepare a gallic acid stock solution with a mass concentration of 200 μg / mL and dilute it into a series of standard solutions with a mass concentration of 0-200 μg / mL. The linear regression equation is Y=0.0108X+0.0743, R 2 =0.9992.

[0069] like Figure 4 As shown, during the fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004 CNN (0-48 hours), the total phenol content showed a trend of first increasing and then decreasing. During the fermentation period of 0-24 hours, the total phenol content in the apricot and plum juice gradually increased from an initial 334.475 mg / L, reaching 476.087 mg / L at 12 hours and 563.436 mg / L at 24 hours, significantly higher than the total phenol content before fermentation. However, it decreased to 452.864 mg / L in the late fermentation period (48 hours). After 24 hours of fermentation, the total phenol content in the apricot and plum juice increased by 68.45% compared to before fermentation. This indicates that Lactobacillus rhamnosus FMBL L23004 CNN can significantly increase the polyphenol content in apricot and plum juice within 24 hours of fermentation, consistent with the optimal fermentation time of 24 hours for Lactobacillus rhamnosus FMBL L23004 CNN obtained in Example 3.

[0070] Example 7: Changes in Antioxidant Activity During Fermentation of Apricot and Plum Juice by Lactobacillus rhamnosus FMBLL23004 CNN

[0071] (1) The prepared inoculated apricot and plum juice was placed in a constant temperature incubator at 37°C for fermentation, and 1 mL of sample was taken from the apricot and plum juice at 0 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, and 48 h of fermentation to determine the antioxidant activity of the fermented juice.

[0072] (2) Determination of ABTS free radical scavenging ability: 7.4 mmol / L ABTS solution and 2.6 mmol / L potassium persulfate solution were mixed in a ratio of 1:1 and reacted in the dark for 12 to 16 hours. The mixture was then diluted with ethanol to an absorbance of 0.70 ± 0.02 at 734 nm. This 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 minutes. The absorbance of the sample was measured at 734 nm. s The blank group was distilled water containing ABTS, and the control group was distilled water and sample. The absorbance was measured as A b and A c .

[0073]

[0074] (3) Determination of DPPH free radical scavenging ability: Prepare 0.025 g / L DPPH solution, take 0.1 mL of juice sample and mix it evenly with 3.9 mL of DPPH solution, react in dark conditions for 30 min, and measure its absorbance at 515 nm as Bs. In addition, replace juice with 0.1 mL of anhydrous ethanol, mix it evenly with 3.9 mL of DPPH solution, and measure its absorbance as Bc, which serves as a blank control group.

[0075]

[0076] The results of ABTS free radical scavenging rate and DPPH free radical scavenging rate are as follows Figure 5 As shown, during the fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBLL23004CNN (0-48 hours), the ABTS and DPPH radical scavenging rates both showed an initial upward trend followed by a downward trend. At 24 hours of fermentation, the ABTS radical scavenging rate reached 93.51%, a significant increase of 21.69% compared to the unfermented apricot and plum juice (76.84%); the DPPH radical scavenging rate reached 53.84%, a significant increase of 72.95% compared to the unfermented apricot and plum juice (31.13%). However, at 48 hours of fermentation, the ABTS radical scavenging rate decreased to 83.32%, and the DPPH radical scavenging rate decreased to 43.22%. These results demonstrate that fermentation of apricot and plum juice by Lactobacillus rhamnosus FMBL L23004CNN significantly increased the ABTS and DPPH radical scavenging rates of apricot and plum juice, indicating that fermented apricot and plum juice has the potential to become a product with excellent antioxidant activity.

[0077] Example 8. α-Amylase and α-Glucosidase Inhibitory Activities of Fermented Apricot and Plum Juice

[0078] (1) Determination of α-glucosidase activity inhibition ability

[0079] 50 μL of sample and 100 μL of 0.2 U / mL α-glucosidase solution were mixed in a test tube and reacted at 37°C for 10 min; then 50 μL of 5 mmol / L p-nitrophenol-α-D-pyranoglucoside solution was added, mixed and reacted in a 37°C constant temperature water bath for 20 min, followed by addition of 50 μL of 0.2 mol / L Na2CO3 solution to terminate the reaction, and the absorbance of the reaction solution was measured at a wavelength of 400 nm.

[0080]

[0081] Wherein: A is the sample group, containing sample solution and α-glucosidase solution; B is the sample blank group, containing sample solution but not α-glucosidase solution; C is the control group, containing α-glucosidase solution but not sample solution; D is the blank group, containing neither sample solution nor α-glucosidase solution.

[0082] (2) Determination of α-amylase activity inhibition ability

[0083] Pipette 125 μL of sample solution and mix equal volumes of 1 mg / mL α-amylase solution. Incubate at 37°C for 15 minutes. Then, add the reaction solution to 250 μL of 1% soluble starch solution. Incubate at 37°C for 15 minutes, then add 500 μL of DNS solution. After boiling in a water bath for 5 minutes, rapidly cool to room temperature. Dilute 20-fold, allow to stand at room temperature, and measure absorbance at 540 nm. Use PBS solution (0.1 mol / L, pH 6.8) as a blank control for the α-amylase solution and the sample to be tested.

[0084]

[0085] Wherein: A is the sample group, containing sample solution and α-amylase solution; B is the sample blank group, containing sample solution but not α-amylase solution; C is the control group, containing α-amylase solution but not sample solution; D is the blank group, containing neither sample solution nor α-amylase solution.

[0086] Table 2 α-amylase and α-glucosidase inhibitory activities

[0087]

[0088] The results, shown in Table 2, show that fermentation of apricot and plum juice with Lactobacillus rhamnosus FMBL L23004 CNN resulted in inhibition rates of 91.32% for α-amylase and 86.59% for α-glucosidase, respectively, representing increases of 43.35% and 76.03%, respectively, compared to unfermented apricot and plum juice. This suggests that fermentation with Lactobacillus plantarum FMBL L2323004 CNN significantly enhances the blood sugar-lowering potential of apricot and plum juice and can be used in the preparation of blood sugar-lowering products.

[0089] Example 9: Preparation of apricot and plum solid beverage

[0090] 1.0×10 7 Lactobacillus rhamnosus FMBL L23004 CNN at a concentration of 100 CFU / mL was added to the apricot-plum juice prepared in the above example. After fermentation at 37°C for 24 hours, 3-10% maltodextrin, 0.5-1% trehalose, and 1% galacto-oligosaccharide were added. After uniform mixing, the fermented apricot-plum juice freeze-dried powder was prepared by freeze-drying or spray-drying to obtain an apricot-plum solid beverage. It should be noted that any values ​​of maltodextrin and trehalose within the above ranges can be used to prepare the solid beverage.

[0091] In summary, the present invention provides the application of Lactobacillus rhamnosus FMBL L23004 CNN in the fermentation of apricot and plum juice. During the fermentation of apricot and plum juice, the growth of Lactobacillus plantarum FMBL L23249 was good, from the initial 1.01×10 7 The CFU / mL increased to 5.10×10 9 CFU / mL, with the advantage of stable growth; the total acid content of apricot and plum juice showed an overall upward trend during the fermentation process of 0-48h, the pH showed an overall downward trend, and the total phenol content showed a trend of first increasing and then decreasing; after 24h of fermentation, the total phenol content in apricot and plum juice increased from the initial 334.475mg / L to 563.436mg / L, a significant increase of 68.45%; the ABTS and DPPH free radical scavenging rates of the fermented apricot and plum juice increased by 21.69% and 72.95% respectively compared with those before fermentation; the inhibition rates of α-amylase and α-glucosidase increased by 43.35% and 76.03% respectively; it can be widely used in the fermentation of apricot and plum juice to extend the shelf life.

Claims

1. Application of Lactobacillus paracasei FMBL L23004 CNN in fermenting apricot plums, characterized in that: The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

2. An apricot and plum product, characterized in that: The apricot and plum product is obtained by fermenting apricot and plum or apricot and plum products with Lactobacillus rhamnosus FMBL L23004 CNN. The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a preservation number of CCTCC NO: M 20231099.

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

4. A liquid apricot-plum beverage with significantly increased total phenol content, characterized in that: The apricot-plum liquid beverage is obtained by fermentation of Lactobacillus rhamnosus FMBL L23004 CNN. The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

5. The method for preparing apricot-plum liquid beverage according to claim 4, characterized in that: The steps include: (1) Weigh apricot and plum fruits, wash them, drain them and set aside; (2) adding distilled water to the apricot and plum fruits obtained in step (1), beating into pulp, filtering, adding 3% to 7% w / v glucose and 0.3% to 1.5% w / v casein, and stirring evenly to obtain apricot and plum juice; (3) placing the apricot and plum juice obtained in step (2) at 95° C. for sterilization for 10 min, cooling to room temperature, and placing in a 4° C. refrigerator for later use; (4) Placing the bacterial liquid of Lactobacillus rhamnosus FMBL L23004 CNN on MRS solid medium for anaerobically culturing, activating, and picking a single colony for subculture in MRS liquid medium; (5) Take the second-generation bacterial solution obtained in step (4), centrifuge it, remove the supernatant, wash the precipitate, centrifuge it, and resuspend it so that the bacterial density reaches 1.0×10 7 CFU / mL; inoculate it into the apricot and plum juice obtained in step (3), culture it statically, and obtain a 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%, the amount of casein added is 0.3% to 0.9%, and gauze with a mesh size of 100 to 300 is used for filtering; and the culture time in step (5) is 0h to 48h.

7. Application of apricot and plum fermented with Lactobacillus paracasei FMBL L23004 CNN in the preparation of antioxidant products, characterized in that: The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

8. Application of apricot plum fermented with Lactobacillus paracasei FMBL L23004 CNN in inhibiting α-glucosidase activity or preparing α-glucosidase inhibitors, characterized in that: The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

9. Application of apricot plum fermented with Lactobacillus paracasei FMBL L23004 CNN in inhibiting α-amylase activity or preparing α-amylase inhibitors, characterized in that: The Lactobacillus rhamnosus FMBL L23004CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M20231099.

10. Application of apricot and plum fermented with Lactobacillus paracasei FMBL L23004 CNN in the preparation of a blood sugar lowering product, characterized in that: The Lactobacillus rhamnosus FMBL L23004 CNN was deposited in the China Center for Type Culture Collection on June 26, 2023, with a deposit number of CCTCC NO: M 20231099.

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