A Lactobacillus pentosus Lp-16 strain and its application

Abstract

The present invention relates to the field of microbial technology. The present invention discloses a Lactobacillus pentosus Lp-16 strain and its application. The deposit number of the strain is: CGMCC No. 32508. After fermentation with the Lactobacillus pentosus Lp-16 in the present invention, rare ginsenosides can be produced, so that the physiological activity of fermented ginseng is enhanced, the flavor of ginseng is improved, the bitterness is reduced, and the volatile flavor substances alcohols, esters, ketones, and aldehydes produced are increased, providing the fermented product with fruity and fermented rice flavors.

Description

Technical Field

[0001] The present disclosure relates to the field of microbial technology, and in particular, to a Lactobacillus pentosus Lp-16 strain and an application thereof. Background Art

[0002] As a precious traditional Chinese medicine, ginseng has a cultivation history of more than 1,000 years, and large-scale cultivation has been more than 400 years. In addition to China, Korean and Japanese scientists have also conducted extensive research on ginseng and found that it has many pharmacological effects. Ginseng can synthesize more ATP for learning and memory by increasing the brain's glucose uptake and glucose utilization; ginseng can improve the body's immune function, regulate the function of the endocrine system, prolong cell life, eliminate free radicals, delay brain aging, and improve brain function; ginseng has a two-way regulatory effect on blood vessels and blood pressure, and ginsenosides can reduce the lactic acid content of the brain and myocardium under severe hypoxia and protect myocardial capillaries; ginsenosides have an antioxidant effect, can enhance the excitatory effect of the nervous system, enhance its inhibitory process to balance the two neural processes of excitation and inhibition, improve human intelligence and physical labor efficiency, and increase anti-aging properties. Ginseng can fight tumors. In multiple clinical trials, it can prevent tumor cell cycle circulation, promote tumor cell apoptosis, and reduce tolerance when combined with chemotherapy drugs.

[0003] Various saponins in ginseng can improve thinking and collective activity abilities. For example, ginsenoside Rg3 can prevent endothelial cell apoptosis by inhibiting the mitochondrial apoptosis pathway. Ginsenoside Rd can enhance the proliferation of neural stem cells, but does not affect the differentiation of neural stem cells in vivo and in vitro. Ginsenosides can improve human immunity. For example, Rh1 can promote T cell proliferation induced by endothelial cell proliferation, Rg1 can increase the weight of the spleen and thymus of normal mice, and enhance the phagocytic function of macrophages. Ginsenosides can enhance memory. For example, Rb1 can improve learning memory and hippocampal-dependent effects, and Rg1 can affect and improve human cognitive function and enhance working memory. In terms of anti-tumor, Rg3 can effectively kill tumor cells.

[0004] According to the records in books such as Compendium of Materia Medica and Chinese Pharmacopoeia, the production and development of fermented Chinese medicine in my country has a history of thousands of years. The earliest fermented Chinese medicine was Qu-type Chinese medicine, including red yeast rice, Liushenqu, and Banxiaqu. Traditional Chinese medicine fermentation does not ferment Chinese medicine in a targeted manner, but uses derived microorganisms in the environment to complete fermentation under conditions where the ambient temperature and humidity cannot be accurately controlled. This process has many disadvantages, such as low purity of the strain, simple fermentation conditions, and lack of standardized models, so the stability of quality is difficult to guarantee. This technical limitation has led to the slow development of fermented Chinese medicine.

[0005] Modern Chinese medicine fermentation is a new process that combines modern processes such as fermentation engineering with traditional Chinese medicine fermentation. The fermentation process mainly involves adding one or more beneficial bacteria to Chinese medicinal materials, and using the enzymes produced during the growth and metabolism of microorganisms to react with the complex active ingredients in Chinese medicine. This can not only increase the content of active ingredients, but also use the catalytic effect of enzymes to accelerate the completion of the reaction. In modern Chinese medicine fermentation, probiotics are generally used for fermentation. They can secrete dozens of extracellular enzymes during metabolism, some of which can directly hydrolyze cellulose, hemicellulose and other substances in the cell wall that make the cell wall dense, destroy its corresponding structure, promote the dissolution of active ingredients, and improve the efficacy. In the process of probiotic fermentation, macromolecules can be decomposed into small molecules through the role of mediators, which are easier to pass through the blood-brain barrier and combine with human proteins, making absorption faster and more complete. Some Chinese medicines contain toxic ingredients, such as alkali substances, heavy metal substances, and toxic protein substances. Probiotics can play their decomposition and transformation role, decompose or structurally modify toxic ingredients to reduce the toxic side effects of Chinese medicine.

[0006] Lactobacillus pentosus belongs to the family Lactobacillusaceae. It is a non-spore-forming Gram-positive bacterium with outstanding metabolic capacity. It can widely utilize a variety of carbon sources, such as pentose, hexose, and lignocellulose hydrolysate for lactic acid fermentation, showing its great potential in the field of biotransformation. In addition, Lactobacillus pentosus can also produce antibacterial substances such as hydrogen peroxide, organic acids and bacteriocins during the fermentation process, which also gives it a broad application prospect in the production of food preservatives. Lactobacillus pentosus can be widely present in the fermentation process of various foods, such as kimchi, yogurt and some wines, and plays a key role in the flavor, texture and safety of the products.

[0007] As a probiotic with unique fermentation characteristics, Lactobacillus pentosus has not yet been widely used in the ginseng fermentation industry. Experimental data show that Lactobacillus pentosus has excellent effects in the ginseng fermentation process, and can efficiently convert ginsenosides to produce a variety of compounds with potential pharmacological activity. These compounds show significant advantages in improving liver function and anti-inflammation.

[0008] During the fermentation process, microorganisms will produce good flavors, which can neutralize the bitterness and sourness of the medicinal materials themselves. When used in ginseng products, they can neutralize the original medicinal flavor, sourness and bitterness of ginseng, greatly improving the taste and acceptance of the product.

[0009] CN109182441A discloses a method for preparing ginsenoside Rb1 fermentation broth, aiming to explore its biotransformation effect through microbial fermentation technology. The specific steps are briefly described as follows: 1) Add 1-5g ginsenoside Rb1 to each liter of MRS culture medium, adjust the pH to 5.0-5.5 after fully dissolving; 2) Sterilize the MRS liquid culture medium containing the ingredient under strict aseptic operation; 3) Introduce fermented lactobacillus into the above culture medium at an inoculation rate of 1%-5%, and culture at a constant temperature shaker at 33°C to 40°C at a speed of 70 to 130 rpm for 5 to 7 days. The experimental results show that after the action of fermented lactobacillus, ginsenoside Rb1 may generate derivatives such as Rg3 and F2 during the biotransformation process. These derivatives show significant relief and improvement effects on fatty liver damage induced by high-fat diet and the accompanying inflammatory response, while Rb1 has no similar effect. This method focuses on the direct fermentation and utilization of ginsenoside monomers. However, since the fermentation raw materials need to be extracted and purified from ginseng in advance or directly purchased, the overall cost is relatively high. In summary, the current fermented ginseng preparation method has the problems of high cost, poor flavor and rough taste. Therefore, it is necessary to find a suitable ginseng fermentation method to solve the above problems. Summary of the invention

[0010] Technical issues solved:

[0011] One aspect of the present invention is to provide a Lactobacillus pentosus Lp-16 strain for ginseng fermentation in view of the problems of high cost, poor flavor and rough taste in the prior art preparation method of fermented ginseng.

[0012] Technical solution:

[0013] A Lactobacillus pentosus Lp-16 strain, the preservation number of which is CGMCC No. 32508.

[0014] The Lactobacillus pentosus Lp-16 strain described in the present invention is deposited in the General Microbiology Center (CGMCC) of the China Microbiological Culture Collection Administration, the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, the deposit date is November 6, 2024, and the deposit number is CGMCC NO. 32508.

[0015] Another aspect of the present invention is to provide the use of the above-mentioned Lactobacillus pentosus Lp-16 strain in ginseng fermentation.

[0016] Another aspect of the present invention is to provide a method for preparing a ginseng fermentation product, comprising the following steps:

[0017] Step 1) washing and pulping fresh ginseng to obtain liquid ginseng pulp;

[0018] Step 2) inoculating the above-mentioned Lactobacillus pentosus Lp-16 strain into a liquid ginseng culture medium, adding the liquid ginseng slurry obtained in step 1), and performing fermentation conversion at a constant temperature of 35-38°C;

[0019] Step 3) drying the product obtained in step 2) to obtain the ginseng fermentation product.

[0020] Specifically, in some embodiments, the method for preparing the ginseng fermentation product comprises:

[0021] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0022] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0023] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0024] (4) inoculating the liquid ginseng culture medium with bacterial strains, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0025] (5) The liquid ginseng culture medium is placed in a drying oven and dried for a certain period of time to obtain a ginseng fermentation product.

[0026] Preferably, in some embodiments, the above method for obtaining pretreated ginseng further comprises using ultrasonic cleaning, or using other solutions to achieve the purpose of cleaning and sterilization.

[0027] Preferably, in some embodiments, the liquid ginseng culture medium in step 2) above comprises water, corn starch and brown sugar, wherein the total concentration of the corn starch and brown sugar is 50-80 g / L.

[0028] Preferably, in some embodiments, the effective bacterial content of the Lactobacillus pentosus Lp-16 strain in the above step 2) is 160 billion to 260 billion CFU / g.

[0029] Preferably, in some embodiments, the fermentation conversion in the above step 2) is to inoculate the strain into the liquid ginseng culture medium at a total inoculation volume of 2-10 ml / L.

[0030] Preferably, in some embodiments, the setting temperature of the drying in the above step 3) is 100° C. and the drying time is 60 min.

[0031] Another aspect of the present disclosure is to provide a method for preparing ginseng fermentation clear liquid, comprising freeze-drying the homogenate of the ginseng fermentation product obtained above, taking 0.30 g of the freeze-dried powder, placing it in a stoppered conical flask, adding 25 mL of 80% methanol, weighing the weight after sealing, shaking well, ultrasonically extracting at 250 W and 50 kHz for 1 hour, collecting the supernatant by centrifugation, extracting the precipitate twice under the same conditions, and collecting the supernatant respectively; after evaporating the supernatant, dissolving it with 100% methanol and fixing the volume to 10 ml respectively, and filtering the solution through a 0.45 μm microporous filter membrane to obtain the ginseng fermentation clear liquid.

[0032] Another aspect of the present disclosure is to provide a ginseng fermentation product, which is prepared by the above preparation method.

[0033] In some embodiments, the fermented ginseng product can be added with appropriate auxiliary materials and prepared into an oral liquid, powder or paste by conventional methods.

[0034] Beneficial effects:

[0035] The present invention studies the effect of Lactobacillus pentosus Lp-16 fermentation on ginseng fiber structure and flavor. The results show that the fermentation of Lactobacillus pentosus Lp-16 has a better effect on the change of ginseng fiber structure and flavor.

[0036] The present invention studies the effect of edible fungus fermentation on the content of ginsenosides, polysaccharides and flavonoids, and finds that the total ginsenosides, total polysaccharides and total flavonoids in black ginseng are all increased compared with ginseng. As several main medicinal ingredients of ginseng, the content of total ginsenosides, total polysaccharides and total flavonoids in black ginseng is increased after fermentation.

[0037] The invention studies the influence of edible fungi fermentation on the color of ginseng and finds that the color of fresh ginseng fermented with mixed edible fungi for 2-4 days becomes darker, slightly lighter than ginseng, and more beautiful.

[0038] The present invention studies the effect of edible fungus fermentation on ginseng flavor and finds that the flavor of ginseng fermented by Lactobacillus pentosus Lp-16 strain is enhanced, its bitterness is reduced, and the volatile flavor substances alcohols, esters, ketones, and aldehydes produced are increased, providing the fermented product with fruity and fermented rice flavor.

[0039] Biodeposit Information:

[0040] Deposit number: CGMCC No. 32508

[0041] Deposit date: November 6, 2024

[0042] Depository: China General Microbiology Center, CGMCC, Address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing

[0043] Classification name: Lactobacillus pentosus. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The genome map of Lactobacillus pentosus Lp-16 strain L. pentosus Lp-16 in the embodiment of the present invention;

[0045] Figure 2 The volatile metabolome electron flow diagrams of the products obtained in the embodiments of the present invention at two stages, wherein the upper diagram is the volatile metabolome electron flow diagram of fresh ginseng, and the lower diagram is the volatile metabolome electron flow diagram of fermented ginseng;

[0046] Figure 3 This is a graph showing the results of the determination of total saponin contents of fresh ginseng and fermented ginseng in the embodiments of the present invention;

[0047] Figure 4 This is the electronic tongue radar diagram of the product obtained in the embodiment of the present invention;

[0048] Figure 5 This is the PCA diagram of the electronic tongue product obtained in the embodiment of the present invention;

[0049] Figure 6 This is a graph showing the pH change curve of the product obtained in the embodiment of the present invention;

[0050] Figure 7 The flowchart of the fermentation of ginseng by the Lactobacillus pentosus Lp-16 strain in the embodiment of the present invention. DETAILED DESCRIPTION

[0051] The present invention discloses a Lactobacillus pentosus Lp-16 strain and its application. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It should be particularly pointed out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention, and relevant personnel can obviously modify or appropriately change and combine the contents described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0052] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Unless otherwise expressly indicated, throughout the specification and claims, the term "including" or its variations such as "comprising" or "including" etc. will be understood to include the stated elements or components without excluding other elements or other components. The terms "such as", "for example", etc. are intended to refer to exemplary embodiments and are not intended to limit the scope of the present disclosure.

[0053] Example:

[0054] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments.

[0055] The preparation method of the Lactobacillus pentosus Lp-16 strain used in this embodiment is:

[0056] By isolating and screening the Lactobacillus pentosus from natural kimchi. Collect fresh kimchi samples and dilute them with sterile physiological saline. Inoculate the dilution into a selective culture medium containing pentose, culture it using a spreading method or a spot method, and culture it anaerobically at 37°C for 24 to 48 hours. After culture, select typical lactic acid bacteria-like colonies according to colony morphology, purify them and re-culture them. The strain was identified by 16S rRNA gene sequencing and was ultimately confirmed to be Lactobacillus pentosus. The screened strain can be further stored in a -80°C refrigerator for future use. The genome map of the Lactobacillus pentosus Lp-16 strain L. pentosus Lp-16 is shown in Figure 1 shown.

[0057] Example 1: Preparation of ginseng fermentation products

[0058] Fresh ginseng was selected as the fermentation object, and Lactobacillus pentosus Lp-16 strain was selected as the fermentation bacteria. The specific operation is as follows (process flow chart as follows Figure 7 shown):

[0059] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0060] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0061] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0062] (4) inoculating 2% of the Lactobacillus pentosus Lp-16 strain into the liquid ginseng culture medium, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0063] (5) The liquid ginseng culture medium is placed in a drying oven and dried for a certain period of time to obtain a ginseng fermentation product.

[0064] The electron flow diagram of the volatile metabolome of the above raw material fresh ginseng and the product ginseng fermentation product is as follows: Figure 2 shown.

[0065] Example 2: Preparation of fermented ginseng enzyme

[0066] The fermentation object is fresh ginseng, and the fermentation bacteria is Lactobacillus pentosus Lp-16 strain. The specific operation is as follows:

[0067] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0068] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0069] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0070] (4) inoculating 2% of the Lactobacillus pentosus Lp-16 strain into the liquid ginseng culture medium, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0071] (5) The slurry of ginseng fermentation product was freeze-dried, and 0.30 g of freeze-dried powder was placed in a stoppered conical flask, and 25 mL of 80% methanol was added. The flask was sealed and weighed, and the mixture was shaken. Ultrasonic extraction was performed at 250 W and 50 kHz for 1 h, and the supernatant was collected by centrifugation. The precipitate was extracted twice under the same conditions, and the supernatants were collected respectively. After the supernatant was evaporated, it was dissolved in 100% methanol and the volume was adjusted to 10 ml. The solution was filtered through a 0.45 μm microporous filter membrane to obtain the ginseng fermentation clear liquid.

[0072] Example 3: Preparation of fermented ginseng extract

[0073] The fermentation object is fresh ginseng, and the fermentation bacteria is Lactobacillus pentosus Lp-16 strain. The specific operation is as follows:

[0074] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0075] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0076] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0077] (4) inoculating 2% of the Lactobacillus pentosus Lp-16 strain into the liquid ginseng culture medium, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0078] (5) Take an appropriate amount of ginseng, add 60-85% ethanol solution and perform heating reflux extraction three times, the first time adding 60-85% ethanol solution to extract for 1.5 hours, the second time adding 60-85% ethanol solution to extract for 1.5 hours, and the third time adding 60-85% ethanol solution to extract for 1.5 hours to obtain ginseng extract and ginseng residue.

[0079] (6) The ginseng extract is decompressed to recover ethanol until there is no alcohol taste, and then concentrated into an extract to obtain a ginseng extract.

[0080] Example 4: Preparation of flavored fermented ginseng powder

[0081] The fermentation object is fresh ginseng, and the fermentation bacteria is Lactobacillus pentosus Lp-16 strain. The specific operation is as follows:

[0082] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0083] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0084] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0085] (4) inoculating 2% of the Lactobacillus pentosus Lp-16 strain into the liquid ginseng culture medium, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0086] (5) Take an appropriate amount of ginseng, add 60-85% ethanol solution and perform heating reflux extraction three times, the first time adding 60-85% ethanol solution to extract for 1.5 hours, the second time adding 60-85% ethanol solution to extract for 1.5 hours, and the third time adding 60-85% ethanol solution to extract for 1.5 hours to obtain ginseng extract and ginseng residue.

[0087] (6) The ginseng residue is freeze-dried, broken into uniform powder, and apple powder, vitamin C and soluble starch are added and mixed evenly, and then the mixture is put into a sealed can for sealing and moisture-proof treatment to obtain flavored fermented ginseng powder.

[0088] Example 5: Preparation of fermented ginseng enzyme beverage

[0089] The fermentation object is fresh ginseng, and the fermentation bacteria is Lactobacillus pentosus Lp-16 strain. The specific operation is as follows:

[0090] (1) Wash fresh ginseng with water until there is no obvious sand or impurities on the surface, immerse it in hot water, take it out after the water cools down, and scrub it until it turns light yellow to obtain pre-treated ginseng;

[0091] (2) Put the pretreated ginseng into a wall breaking machine and beat it until there is no obvious fiber, thereby obtaining liquid ginseng pulp;

[0092] (3) Mixing a certain amount of water, corn starch and brown sugar to obtain a liquid ginseng culture medium;

[0093] (4) inoculating 2% of the Lactobacillus pentosus Lp-16 strain into the liquid ginseng culture medium, adding liquid ginseng slurry, and performing fermentation conversion at a constant temperature of 35-38° C. for 2-4 days;

[0094] (5) The slurry of ginseng fermentation product was freeze-dried, and 0.30 g of freeze-dried powder was placed in a stoppered conical flask, and 25 mL of 80% methanol was added. The flask was sealed and weighed, and the mixture was shaken. Ultrasonic extraction was performed at 250 W and 50 kHz for 1 h, and the supernatant was collected by centrifugation. The precipitate was extracted twice under the same conditions, and the supernatants were collected respectively. After the supernatant was evaporated, it was dissolved in 100% methanol and the volume was adjusted to 10 ml. The solution was filtered through a 0.45 μm microporous filter membrane to obtain the ginseng fermentation clear liquid.

[0095] (6) Dilute the clear liquid, add sugar and citric acid for flavoring, and bottle it as fermented ginseng beverage.

[0096] Example 6: Preparation of fermented ginseng slices

[0097] Fresh ginseng was also selected as the fermentation object, and the fermentation strain continued to use the Lactobacillus pentosus Lp-16 strain. The specific preparation steps are as follows:

[0098] (1) Wash the fresh ginseng carefully to remove the dirt and impurities on the surface, then immerse it in warm water for a short time to soften the tissue, then take it out to air dry or blow dry it, and cut it into thin slices to obtain the raw material of ginseng slices;

[0099] (2) preparing a fermentation medium specifically for ginseng slices, which is a mixture of appropriate amounts of water, glucose, yeast extract and a small amount of inorganic salts to ensure adequate nutrition during the fermentation process;

[0100] (3) Spread the cut ginseng slices evenly on the sterilized culture medium, and then inoculate the Lactobacillus pentosus Lp-16 strain at a ratio of 3%, ensuring that the bacterial liquid evenly covers the surface of the ginseng slices;

[0101] (4) Place the inoculated ginseng slices in a sealed fermentation tank and set the temperature to 37±1°C. Maintain this constant temperature condition for static fermentation for 3 to 5 days. During this period, check the fermentation status regularly to ensure an anaerobic or micro-aerobic environment to promote lactic acid bacteria fermentation.

[0102] (5) After fermentation is completed, the ginseng slices are taken out, and the surface is gently rinsed with sterile water to remove the residual fermentation medium, and then low-temperature drying is performed to maintain the shape of the ginseng slices and concentrate their flavor components;

[0103] (6) The dried fermented ginseng slices are packaged, and vacuum-sealed packaging can be used to extend the shelf life, thereby finally obtaining finished fermented ginseng slices.

[0104] This fermented ginseng slice not only retains the original nutrients of ginseng, but also produces more healthy metabolites such as lactic acid through the fermentation process, which enhances its health function and gives it a unique flavor.

[0105] Example 7: Detection of ginsenoside content in ginseng fermentation products

[0106] The ginseng fermentation product obtained in Example 1 was tested using the following method:

[0107] Ginseng fermentation products were powdered and passed through an 80-mesh sieve for later use; 0.5000 g of the sample was accurately weighed and placed in a 12 mL centrifuge tube, 8.0 mL of chromatographically pure methanol was accurately added to the centrifuge tube, mixed, ultrasonically extracted for 30 min, centrifuged at 4000 r / min for 10 min, the supernatant was transferred to a 25 mL volumetric flask, the solid fungus precipitated at the bottom of the centrifuge tube was extracted twice according to the above method, the supernatants were combined, and the volume was fixed to 25 mL with chromatographically pure methanol;

[0108] Agilent 1260 high performance liquid chromatograph was used, the chromatographic column was Agilent Eclipse C18plus (150mm×4.6mm, 5μm), the mobile phase was acetonitrile-0.1% phosphoric acid aqueous solution for gradient elution, the flow rate was 1mL / min, the column temperature was 30℃, and the detection wavelength was 203nm. Ginsenosides before and after fermentation were analyzed by retention time for qualitative analysis and external standard method for quantitative analysis, with ginsenoside standards as the reference.

[0109] The results are as follows Figure 3 shown.

[0110] Example 8: Using electronic tongue to measure fresh ginseng and fermented ginseng

[0111] The ginseng fermentation product obtained in Example 1 was taken and the fresh ginseng and the fermented ginseng were measured using an electronic tongue.

[0112] Take the fresh ginseng in Example 1, soak and sterilize, wash and dry it, then put it into a sterilizer and steam it at 100° C. for 60 min, then put it into a drying oven and dry it at 95° C. for 60 min, and repeat this process 5 times to obtain the processed black ginseng.

[0113] According to the method in Example 1, fresh ginseng was fermented and transformed, the fermented ginseng was taken out from the culture medium, dried and put into a sterilizer and steamed at 100° C. for 60 min, and then put into a drying oven and dried at 95° C. for 60 min, and this process was repeated 5 times to obtain fermented black ginseng.

[0114] The black ginseng and fermented black ginseng obtained above were measured using an electronic tongue.

[0115] The method for measuring electronic tongue data is as follows: accurately weigh 2 mL of sample into a 10 mL headspace bottle, cover, seal, number, and wait for measurement. Manual injection was used, headspace heating was performed for 5 min, temperature was 75°C; carrier gas was synthetic dry air, injection volume was 1500 μL, injection speed was 150 mL / s, data acquisition cycle was 1.0 s, data acquisition time was 2 min, data acquisition delay was 3 min, and data acquisition flow rate was 150 mL / min. Parallel measurements were performed 5 times, and the stable signals obtained by the sensor in the last 3 times were analyzed.

[0116] The electronic tongue radar images of fresh ginseng and fermented ginseng are as follows: Figure 4 As shown in Figure 2, the PCA graphs of electronic tongue of fresh ginseng and fermented ginseng are as follows: Figure 5 shown.

[0117] Example 9: Measurement of fresh ginseng and fermented ginseng using a pH meter

[0118] The ginseng fermentation product obtained in Example 1 was taken and the fresh ginseng and the fermented ginseng were measured using a PHS-3BW digital pH meter.

[0119] Method for determining pH: dilute the bacterial solution in proportion and apply it on a plate for counting analysis. Use a PHS-3BW digital pH meter to measure the pH of the fermented ginseng sample every 1 hour.

[0120] The results are as follows Figure 6 shown.

[0121] Example 10: Determination of volatile metabolites

[0122] Take the ginseng fermentation product obtained in Example 1, and use GC-MS volatile metabolomics technology to determine the volatile metabolites in the sample. With the screening criteria of log2(FC) > 0.6 or -0.2 < log2(FC) < 0, P value < 0.05, screen the significantly different metabolites between ginseng and fermented ginseng. Combine online databases such as KEGG, HMDB, and PUBCHEM, and identify metabolites through the m / z and retention time of compounds. The results are shown in Table 1. A total of 36 different metabolites in 11 categories were screened out from the three samples. The specific information of the substances can be queried on the PUBCHEM website through the CAS number. The results show that these different metabolites are mainly alcohols, aromatic hydrocarbons, terpenes, hydrocarbons, ketones, heterocyclic compounds, and esters. In particular, the changes in flavor-related substances such as esters and lipids are directly related to the improvement of the final flavor characteristics of ginseng products.

[0123] Table 1

[0124]

[0125] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A Lactobacillus pentosus ( Lactobacillus pentosus ) Lp-16 strain, characterized in that The deposit number of this strain is: CGMCC No. 32508.

2. Use of the Lactobacillus pentosus Lp-16 strain as claimed in claim 1 in ginseng fermentation.

3. A method for preparing a ginseng fermentation product, characterized in that: The following steps are involved: Step 1) washing and pulping fresh ginseng to obtain liquid ginseng pulp; Step 2) inoculating the Lactobacillus pentosus Lp-16 strain as claimed in claim 1 into a liquid ginseng culture medium, adding the liquid ginseng slurry obtained in step 1), and performing fermentation conversion at a constant temperature of 35-38° C.; Step 3) drying the product obtained in step 2) to obtain the ginseng fermentation product; Wherein, the liquid ginseng culture medium in step 2) comprises water, corn starch and brown sugar, wherein the total concentration of the corn starch and brown sugar is 50-80 g / L.

4. The preparation method according to claim 3, characterized in that: The step 1) also includes a step of pre-treating the fresh ginseng: washing the fresh ginseng with water until there is no obvious mud or sand impurities on the surface, immersing it in hot water, taking it out after the water cools down, and scrubbing it until it turns light yellow.

5. The preparation method according to claim 3, characterized in that: The effective bacterial content of the Lactobacillus pentosus Lp-16 strain described in step 2) is 160 billion to 260 billion CFU / g.

6. A ginseng fermentation product, characterized in that: The ginseng fermentation product is prepared by the preparation method according to any one of claims 3 to 5.

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