Bifidobacterium animalis subsp. Lactis and application thereof in preparation of hypoglycemic products

Abstract

The invention provides bifidobacterium animalis subsp. Lactis and application thereof in preparation of hypoglycemic products, and belongs to the technical field of probiotics. The invention provides a strain of Bifidobacterium animalis subsp. Lactis BX-259, which is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number is CGMCC No.27838, and the strain of Bifidobacterium animalis subsp. Lactis BX-259 is named as Bifidobacterium animalis subsp. Lactis BX-259. The strain of Bifidobacterium animalis subsp. Lactis BX-259 is named as BX-259. The bifidobacterium animalis subsp. Lactis can be used for preparing the metagen, and the metagen and bread prepared from the metagen can effectively reduce the blood glucose concentration and the blood glucose index.

Description

Technical Field

[0001] The invention belongs to the technical field of probiotics, relates to the preparation of postbiotics, and specifically relates to an animal Bifidobacterium lactis subspecies and an application thereof in the preparation of a blood sugar-lowering product. Background Art

[0002] Glycemic index (GI) refers to the ratio of the area under the plasma glucose tolerance curve 2 hours after ingesting a food containing 50g of carbohydrates and 50g of glucose. FAO / WHO defines the glycemic index as the ratio of the area under the postprandial blood glucose response curve of a food containing 50g of available carbohydrates to the area under the postprandial blood glucose response curve of a standard reference food containing the same amount of available carbohydrates. The GI value is an indicator to describe the degree of effect of carbohydrate foods on postprandial blood glucose. A low GI diet can not only help us better manage blood sugar, but also highlights its importance in weight management, digestion and absorption, diabetes prevention and other aspects.

[0003] Postbiotics are a general term for the metabolites of probiotics after probiotics are processed, including bacteria and metabolites. When a sufficient dose of postbiotics is given to the host, it can benefit the host's health. The components of postbiotics include all bioactive substances in the probiotic fermentation system, including bacterial metabolites and bacterial cell components. The main bioactive components are extracellular polysaccharides, short-chain fatty acids, vitamins, neurotransmitters, peptidoglycan, teichoic acid, proteins and plasmalogens.

[0004] The health benefits of postbiotics mainly rely on the active substances they contain, and the activity of the substances is affected by the preparation method. The method of preparing probiotics into postbiotics involves the technology of bacterial inactivation, and different treatment methods have different effects on postbiotics. Usually, in order to avoid residues, physical inactivation methods are selected to obtain postbiotics, such as heat treatment, high pressure treatment and ultrasonic treatment. Heat treatment is the most commonly used cell inactivation method, but it will increase the roughness of cells, resulting in a decrease in immunomodulatory properties. High pressure treatment requires a relatively long processing time and high energy consumption when applied alone. It can usually be combined with heating and applied in an intermittent form to eliminate bacterial spores. The inactivation of microorganisms by ultrasonic treatment is mainly due to cell wall rupture, disturbance and thinning of the cell membrane, and DNA damage caused by the generation of free radicals. A single treatment method often has the disadvantages of incomplete inactivation or a long time required for inactivation. Therefore, in the actual preparation process of postbiotics, it is usually necessary to select a combined treatment method according to the purpose of preparation to improve production efficiency and obtain suitable postbiotic products. In order to facilitate storage and transportation, drying has become an important part of the preparation process of postbiotics. At present, the main drying technologies include freeze drying, vacuum drying, fluidized bed drying and spray drying. Freeze drying can obtain postbiotics with relatively stable components by sublimation, but it is inefficient, costly and time-consuming. Vacuum drying is a discontinuous process, and its drying is completed by evaporation. The longer the drying time, the lower the survival rate. Fluidized bed drying is a method in which heated gas passes through a solid particle bed and suspends the particles in dry air for drying. However, since the dried bacterial cells are relatively small, the bacteria will be carried away with the dry air during drying, resulting in very low yields. Spray drying is a low-cost, high-yield drying technology. Because of direct contact with high-temperature hot air, the survival rate of bacteria after drying is very low. However, the high outlet temperature of the powdered product can easily cause a large loss of active ingredients in the postbiotics. Therefore, in the actual preparation of postbiotics, it is necessary to select a suitable drying method according to the purpose of preparation.

[0005] People's healthy lives have been greatly affected by obesity and its related metabolic diseases (such as diabetes, obesity, hyperlipidemia, etc.). Postbiotics can be used to prevent, treat or improve related metabolic diseases. Heat-killed Streptococcus salivarius thermophilus subspecies has played a good role in treating diabetic mice, effectively reducing blood sugar levels and reducing insulin resistance. The bacterial fragments of Lactobacillus amyloliquefaciens improved the indicators related to blood lipid levels in obese mice (reduced the levels of low-density lipoprotein-cholesterol and triglycerides in plasma), thereby significantly reducing the atherosclerosis index. In terms of metabolism, the study found that supplementation with heat-killed Lactobacillus plantarum L-137 can alleviate the weight gain and increased levels of plasma glucose, cholesterol, alanine aminotransferase and aspartate aminotransferase in diet-induced obese mice. This study showed that Lactobacillus plantarum L-137 significantly downregulated inflammation-related genes including F4 / 80, CD11c and IL-1β in the epididymal adipose tissue of experimental mice, reduced the level of plasma lipopolysaccharide binding protein (endotoxinemia marker), and improved metabolic abnormalities and adipose tissue inflammation caused by obesity (Yoshitake R, et al. Heat-killed Lactobacillus plantarum L-137). Lactobacillus plantarum L-137 attenuates obesity and associated metabolic abnormalities in C57BL / 6J mice on a high-fat diet[J]. Bioscience of Microbiota Food and Health , 2020.). Ben Othman M et al. also demonstrated that oral administration of inactivated Bifidobacterium cells for 5 weeks alleviated the increase in body weight, adipose tissue mass and blood glucose levels in obese diabetic mice, while reducing cholesterol and triglyceride levels (Othman MB, Sakamoto K. Effect of inactivated Bifidobacterium cells Bifidobacterium longum intake on obese diabetes model mice (TSOD).[J]. Food Res Int , 2020.).

[0006] Bifidobacterium animalis subsp. lactis ( Bifidobacterium animalis subsp. lactis) is a Gram-positive bacillus belonging to the genus Bifidobacterium. The colony is smooth, convex, with complete edges, milky white, shiny and soft. Animal Bifidobacterium lactis subspecies does not form spores, is non-motile, and is an anaerobic organism. Its optimum growth temperature is 3-41°C, its optimum fermentation temperature is 35-40°C, its minimum growth temperature is 25-28°C, and its maximum growth temperature is 43-45°C. Animal Bifidobacterium lactis subspecies is mainly distributed in the human intestine, and is also present in large quantities in the digestive tract of some warm-blooded animals (such as pigs, dogs, mice and bees), indicating that animal Bifidobacterium lactis subspecies is a normal strain existing in the human body. In addition, animal Bifidobacterium lactis subspecies has good acid and bile resistance, can survive in the stomach and intestines of humans and animals, and is widely present in the intestines of humans and animals. Animal Bifidobacterium lactis subspecies is one of the strains that can be used for production and processing. It is widely present in the intestines of humans and animals and is excreted with feces. As a probiotic in the intestinal flora, it is also an edible lactic acid bacteria. Animal Bifidobacterium lactis can also help intestinal peristalsis, and can also enhance the digestive ability of the human body and improve immunity. Therefore, animal Bifidobacterium lactis has become a hot topic of research in recent years as a probiotic bifidobacterium with great potential. Therefore, animal Bifidobacterium lactis is widely used in the production of probiotic preparations for humans and animals as a probiotic, and is constantly being used to make probiotic preparations suitable for humans and animals.

[0007] Prior art CN110604749B is a strain of animal bifidobacterium and its application in controlling diabetes or hyperlipidemia, especially weight gain or obesity. The deposit number of the animal bifidobacterium is CGMCC No. 17308. The present invention also discloses a product composition, which contains bacterial substances and / or metabolites of the animal bifidobacterium. The animal bifidobacterium provided by the present invention is suitable for the specific physiological constitution of Chinese people, and can inhibit α-glucosidase activity, inhibit glucose transport, and improve the body's glucose tolerance level.

[0008] Prior art CN118599718A A strain of Bifidobacterium lactis subsp. MY9 and its application in the preparation of anti-inflammatory and hypoglycemic food and medicine. The invention separates and purifies a strain of Bifidobacterium lactis subsp. ( Bifidobacteriumanimalis subsp. lactis ) MY9 strain, which can not only produce and secrete 3-hydroxybutyric acid, but also inhibit the activity of α-glucosidase. It has multiple functions such as anti-inflammatory, improving intestinal flora, lowering blood sugar and losing weight.

[0009] Since animal Bifidobacterium lactis subspecies has a diversity of sources, it has genetic diversity and functional diversity. However, there are still few studies on the separation and identification, probiotic properties and metabolic mechanisms of animal Bifidobacterium lactis subspecies, which to a certain extent affects the development and utilization of animal Bifidobacterium lactis subspecies. Therefore, it is necessary to explore more new strains based on the different sources of animal Bifidobacterium lactis subspecies, and then determine their efficacy based on the function of the strain or the probiotic metabolites, clarify their application prospects, and enable them to better play a probiotic role. In summary, the research and application of probiotic animal Bifidobacterium lactis subspecies has a broad space for development. Summary of the invention

[0010] The present invention aims at the problems existing in the prior art and provides an animal Bifidobacterium lactis subspecies and an application thereof in preparing a blood sugar-lowering product. Postbiotics are prepared by using animal Bifidobacterium lactis subspecies BX-259, and the postbiotics and bread prepared by the postbiotics can effectively reduce blood sugar concentration or glycemic index.

[0011] To achieve the above purpose, the technical solution adopted by the present invention is as follows: In one aspect, the present invention provides a strain of Bifidobacterium animalis subsp. lactis BX-259, which has a deposit number of CGMCC No. 27838 and is deposited in the General Microbiological Center of China National Microbiological Culture Collection Administration. The 16S rDNA sequence of Bifidobacterium animalis subsp. lactis BX-259 is shown in SEQ ID NO. 1. SEQ ID NO.1:

[0012] Based on the above, the present invention also provides a bacterial agent, including the aforementioned Bifidobacterium animalis subsp. lactis BX-259.

[0013] The present invention also provides the use of the animal Bifidobacterium lactis subspecies BX-259 in the preparation of hypoglycemic postbiotics.

[0014] Accordingly, the present invention protects a postbiotic that can reduce the glycemic index of the human body, wherein the postbiotic comprises the inactivated bacteria or metabolites of the animal Bifidobacterium lactis subsp. BX-259.

[0015] Preferably, the metabolites of the animal Bifidobacterium lactis subsp. lactis BX-259 include organic acids and others, such as lactic acid, citric acid, tartaric acid, malic acid, benzoic acid, succinic acid, 4-hydroxyphenyllactic acid, oxalic acid, short-chain fatty acids, amino acids or antimicrobial peptides.

[0016] Preferably, the short-chain fatty acids include at least one of acetic acid, propionic acid, butyric acid and caproic acid; and the amino acids include at least one of valine, tyrosine, proline, phenylalanine, leucine, isoleucine, alanine, aspartic acid, glutamic acid and lysine.

[0017] Preferably, the postbiotics are obtained by fermenting and inactivating the above-mentioned probiotics.

[0018] Preferably, the preparation method of the postbiotics comprises the following steps: inoculating the probiotics into the liquid, adding lactase, fermenting at a constant temperature, adding or not adding auxiliary materials after stopping the fermentation, then preheating, homogenizing, and finally inactivating.

[0019] Preferably, the preparation method of the postbiotics comprises the following steps: inoculating the probiotics into the liquid, adding lactase, fermenting at a constant temperature of 30-38°C, stopping the fermentation at a pH of 4.5-4.6, adding or not adding auxiliary materials, and then preheating, homogenizing, and then inactivating.

[0020] Preferably, the composition of the feed liquid includes full-fat soybean powder, skim milk powder, sodium citrate and purified water.

[0021] Preferably, before inactivation, the total viable count of the probiotics is ≥ 3.0×10 10 CFU / g. CFU stands for colony forming units.

[0022] Specifically, the preparation method of the postbiotics comprises the following steps: 1) Weighing materials: Mix 4wt% of full-fat soybean powder, 14.5wt% of skim milk powder, 2.5wt% of sodium citrate and the balance of water according to the proportion; 2) Chemical reaction: Chemical reaction at 58°C for 15 min to obtain a liquid feed; 3) Homogenization: at 58°C, the first-stage pressure is 19 Mpa and the second-stage pressure is 5.0 Mpa; 4) Sterilization: The homogenized liquid is sterilized at 93°C for 30 minutes; 5) Cooling: The sterilized liquid is cooled to 35°C; 6) Add bacteria and lactase: Add animal Bifidobacterium lactis subspecies BX-259 to the liquid, with a total inoculation amount of 6×10 6 CFU / g (feed liquid), and add lactase (enzyme activity 5000U / g) 0.5mL / kg (feed liquid); 7) Constant temperature fermentation: Fermentation was carried out at 35℃ until pH reached 4.5-4.6, which took about 18-19 hours. The total number of live probiotics was ≥3.0×10 10 CFU / g; 8) Inactivation: Mix in 18g / kg maltodextrin (fermentation liquid), preheat to 58°C, homogenize at a primary pressure of 19Mpa and a secondary pressure of 5.0Mpa, and then sterilize (inactivation conditions: 85°C, 15min); 9) Spray drying: The inactivated bacterial suspension is spray dried to obtain postbiotic powder.

[0023] Based on the above, the present invention also protects the corresponding preparation method.

[0024] On the other hand, the present invention provides the use of the animal Bifidobacterium lactis subspecies BX-259 or bacterial agent or postbiotic in the preparation of a blood sugar regulating product.

[0025] Accordingly, the present invention protects products including the animal Bifidobacterium lactis subsp. BX-259 or bacterial agent or postbiotic, and the product is a food, a health product or a medicine.

[0026] Preferably, the health care product is used to assist in lowering blood sugar.

[0027] As an example, the product may be a food product including, but not limited to, bread, cake or biscuits.

[0028] In some specific embodiments, the food is bread, and the components of the bread also include black barley whole wheat flour, oat flour, quinoa flour, sugarcane polyphenols, egg liquid, sorbitol liquid, xylitol and purified water.

[0029] Preferably, the components of the bread include, by mass: 30-50 parts of black barley whole wheat flour, 5-10 parts of oat flour, 3-8 parts of quinoa flour, 1-2 parts of sugarcane polyphenols, 3-6 parts of the above-mentioned postbiotics, 5-10 parts of egg liquid, 1-3 parts of sorbitol liquid, 2-4 parts of xylitol, and 10-20 parts of purified water.

[0030] Preferably, the final concentration of the above postbiotics in the bread is ≥50 mg / mL.

[0031] Preferably, the final concentration of the above postbiotics in the bread is 50-100 mg / mL.

[0032] Preferably, the method for preparing bread comprises the following steps: 1) Mix black barley whole wheat flour, oatmeal flour, quinoa flour, egg liquid and purified water; 2) Add xylitol, sorbitol liquid, the above-mentioned postbiotics and sugarcane polyphenols, stir and mix well, and knead until the surface of the dough is dry and smooth; 3) Let the dough rise at room temperature, divide it into individual dough pieces, and then roll the dough pieces into balls for secondary proofing; 4) Bake the dough that has been proofed for the second time, cool it to room temperature after baking, and package it to obtain the finished product.

[0033] Preferably, the method for preparing bread comprises the following steps: 1) Mix the above-mentioned whole wheat barley flour, oatmeal flour, quinoa flour, egg liquid and purified water for 10-15 minutes to make them evenly mixed; 2) Add xylitol, sorbitol liquid, the above-mentioned postbiotics and sugarcane polyphenols and continue to stir and knead until the dough surface is dry, smooth and elastic; 3) Place the prepared dough at room temperature to rise for 1-2 hours, quickly divide it into individual dough pieces, and then roll the dough pieces into balls for secondary rising. The rising temperature is controlled at 30℃-36℃ and the time is 0.5-1.0h; 4) Bake the proofed dough at 150-180℃ for upper heat, 180-200℃ for lower heat, and 65-75% relative humidity for 8-15 minutes, then take it out of the oven. After the bread cools naturally to room temperature, it can be packaged.

[0034] In another aspect, the present invention provides a use of the above-mentioned postbiotics or the above-mentioned products, wherein the use includes lowering human blood glucose concentration or lowering human blood glucose index.

[0035] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a strain of Bifidobacterium animalis subspecies lactis BX-259 ( Bifidobacterium animalis subsp . lactis ), deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number of CGMCC No.27838; 2. The animal Bifidobacterium lactis subspecies BX-259 provided by the present invention can be used to prepare postbiotics, and the postbiotics can also be used to prepare bread. The postbiotics in the bread can be used in combination with sugarcane polyphenols. The effect of reducing blood glucose concentration after the combination of the two is significantly better than that of the single postbiotics and the single sugarcane polyphenols; at the same time, compared with the reference strain animal Bifidobacterium lactis subspecies BB12, the postbiotics containing animal Bifidobacterium lactis subspecies BX-259 and the bread prepared therefrom are more effective in reducing blood glucose concentration and glycemic index.

[0036] 3. After adding postbiotics containing animal Bifidobacterium lactis subspecies BX-259, the bread is fluffier and tastes better.

[0037] Collection Instructions Bacterial species name: Bifidobacterium animalis subsp. lactis; Latin name: Bifidobacterium animalis subsp. Lactis; Strain ID: BX-259; Depository: General Microbiology Center, China Microbiological Culture Collection Administration; Abbreviation of depository institution: CGMCC; Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Deposit date: July 7, 2023; Deposit number (or registration number of the deposit center): CGMCC No.27838. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Effects of postbiotics on blood glucose concentration in mice.

[0039] Figure 2 Effects of postbiotics on the area under the glucose tolerance curve of mice (AUC is the abbreviation for the area under the glucose tolerance curve; the same letters on the bars in the figure indicate no significant difference (P>0.05), and different letters indicate significant difference (P<0.05)).

[0040] Figure 3 Results of human blood sugar test 0h-2h after eating different groups of bread. DETAILED DESCRIPTION

[0041] The following examples are provided to further understand the present invention, are not limited to the best mode of implementation, and are not intended to limit the content and scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the enlightenment of the present invention or by combining the features of the present invention with other prior arts, all falls within the scope of the present invention. If no specific experimental steps or conditions are specified in the examples, the operation or conditions of the conventional experimental steps described in the literature in this field can be carried out. If the manufacturer of the reagents or instruments used is not specified, they are all conventional reagent products that can be obtained commercially. Table 1 describes the sources of key materials and equipment.

[0042] Table 1 Description of key materials and equipment

[0043] In the following preparation examples, embodiments, comparative examples and effect examples: Experimental strain: Bifidobacterium lactis subspecies BX-259 of the present invention ( Bifidobacterium animalis subsp. lactis ), the deposit number is CGMCC No.27838, abbreviated as BX-259.

[0044] Reference strain: Bifidobacterium animalis subsp. lactis BB12 ( Bifidobacterium animalis subsp. lactis ), which is the model strain in this field, referred to as BB12.

[0045] Culture medium for bacterial liquid preparation: MRS liquid culture medium (manufacturer: Haibo Biotechnology, product number: HB0384-1).

[0046] Preparation Example 1: Preparation of bacterial solution 1) Inoculate the strain into the culture medium and culture it anaerobically at 37°C for 24 hours to obtain the first generation of activated strain; 2) Inoculate the first generation activated strain into a new culture medium at a ratio of 5 v / v%, and culture at 37°C for 24 h. After the culture, centrifuge the culture solution at 8000 g at 4°C for 10 min to collect the bacteria. Wash with sterile PBS buffer (pH 7.4) three times, resuspend in PBS solution, and adjust the cell number to 1.0 × 10 9 CFU / mL, and obtain BX-259 and BB12 live bacterial liquid.

[0047] Example 1: A method for preparing postbiotics This embodiment provides a method for preparing postbiotics, comprising the following steps: 1) Weighing materials: 4wt% full fat soy flour, 14.5wt% skim milk powder, 2.5wt% sodium citrate and the balance water, mix evenly according to the proportion; 2) Chemical processing: use a chemical processing machine to chemically process the material for 15 minutes at 58°C to obtain a liquid feed; 3) Homogenization: Use a homogenizer at 58°C, with a first-stage pressure of 19.0 Mpa and a second-stage pressure of 5.0 Mpa for homogenization; 4) Sterilization: The homogenized liquid is sterilized at 93°C for 30 minutes; 5) Cooling: The sterilized liquid is cooled to 35°C; 6) Add bacteria and lactase: Add BX-259 bacterial solution to the cooled liquid, with a total inoculation volume of 6×10 6 CFU / g (feed liquid), and add lactase (enzyme activity 5000U / g) 0.5mL / kg (feed liquid); 7) Constant temperature fermentation: Fermentation was carried out at 35°C until pH reached 4.5-4.6, which took about 18-19 hours. The total number of live probiotics was ≥3.0×10 10 CFU / g; 8) Inactivation: Add 18g / kg maltodextrin (fermentation liquid), preheat to 58°C, homogenize at a primary pressure of 19.0 Mpa and a secondary pressure of 5.0 Mpa, and then sterilize (inactivation conditions 85°C, 15min); 9) Spray drying: Use a spray dryer to spray dry the inactivated bacterial suspension to obtain postbiotic powder.

[0048] Example 2: Detection of probiotic metabolites in postbiotics The probiotic postbiotic powder prepared in Example 1 was used to determine the metabolites contained in the probiotic postbiotic powder using LC-MS. The determination results of the main metabolites are shown in Table 2.

[0049] Table 2 Metabolite detection

[0050] Example 3: A method for preparing bread The bread was prepared in the following steps: 1) Weigh the following materials by weight: 40 parts of black barley whole wheat flour, 8 parts of oat flour, 6 parts of quinoa flour, 1 part of sugarcane polyphenols, 5 parts of postbiotics prepared in Example 1, 8 parts of egg liquid, 2 parts of sorbitol liquid, 3 parts of xylitol, and 15 parts of purified water; 2) Mix black barley whole wheat flour, oatmeal flour, quinoa flour, egg liquid and purified water and stir for 15 minutes to mix them evenly; 3) Add xylitol, sorbitol liquid, postbiotics and sugarcane polyphenols and continue to stir and knead until the dough surface is dry, smooth and elastic; 4) Place the prepared dough at room temperature to rise for 2 hours, quickly divide it into individual dough pieces, and then roll the dough pieces into balls for secondary rising at a controlled temperature of 36°C for 1 hour. 5) Bake the proofed dough at 160℃ for upper heat, 180℃ for lower heat and 70% relative humidity for 10 minutes, then take it out of the oven. After the bread cools down to room temperature naturally, it can be packaged.

[0051] Comparative Example 1: A method for preparing postbiotics Except that the bacterial solution of Bifidobacterium animalis subsp. lactis BX-259 was replaced by the bacterial solution of Bifidobacterium animalis subsp. lactis BB12, the rest was the same as Example 1.

[0052] Comparative Example 2: A method for preparing bread Except that sugarcane polyphenols are not added to the raw materials, the rest is the same as Example 3.

[0053] Comparative Example 3: A method for preparing bread Except that no postbiotics are added to the raw materials, the rest is the same as Example 3.

[0054] Comparative Example 4: A method for preparing bread Except that postbiotics and sugarcane polyphenols are not added to the raw materials, the rest is the same as Example 3.

[0055] Comparative Example 5: A method for preparing bread Except that the postbiotics in Example 1 are replaced by the postbiotics in Comparative Example 1 in the raw materials, the rest is the same as Example 3.

[0056] Effect Example 1: Effect of postbiotics on blood glucose concentration in mice Five-week-old C57BL / 6J male mice (n=18, all from the Experimental Animal Center of Inner Mongolia Agricultural University) were used in the experiment. Animal husbandry and diet formula, including all animal care and experimental procedures, were approved by the Animal Care and Experiment Committee of Inner Mongolia Agricultural University. They were raised under specific pathogen-free conditions with a 12-h day and night light cycle, a temperature of 22±2◦C, and a relative humidity of 55±10%.

[0057] The mice were randomly divided into 3 groups: postbiotic group A (BX-259 postbiotic powder in Example 1, 1 bag / d, 2g / bag, n=6); blank control group B (maltodextrin powder, 1 bag / d, 2g / bag, n=6); model group C (BB12 postbiotic powder in Comparative Example 1, 1 bag / d, 2g / bag, n=6). After 10 weeks of intervention, all mice were fasted but not watered for 12h, and gavaged with 2.5g / kg glucose solution, and the tail vein blood glucose values ​​at 0min, 30min, 60min, 90min and 120min were measured with a blood glucose meter.

[0058] The results are as follows Figure 1 As shown, within 30 minutes after oral administration of glucose, the blood glucose levels of mice in each group showed an upward trend, with the rate of increase A<C<B, and the mice in group A showed normal glucose tolerance. After 30 minutes, the blood glucose levels of each group gradually decreased, and group A returned to the fasting level after 2 hours. Figure 2 The results showed that the AUC (area under the glucose tolerance curve, AUC) of groups A, B and C were 1118±15, 1845±61 and 1512±22, respectively. The AUC of group A was significantly lower than that of the blank control group B and the model group C, indicating that feeding only BX-259 postbiotics could significantly reduce the AUC level of mice, effectively improving blood sugar increase and glucose tolerance level, and the sugar control effect was better than that of BB12 postbiotics.

[0059] Effect Example 2: Lowering blood sugar concentration and glycemic index 1) Experimental methods 1.1. Screening of test subjects The subjects were 25 healthy people with no diabetes, aged between 20 and 25 years old, with an average age of 22 ± 1.14 years old and an average body mass index of 23.05 ± 2.13 kg / m 2 The subjects were randomly divided into 5 groups, with 5 people in each group. The first group ate bread prepared in comparative example 2, recorded as A; the second group ate bread prepared in Example 3, recorded as B; the third group ate bread prepared in comparative example 3, recorded as C; the fourth group ate bread prepared in comparative example 4, recorded as D; the fifth group ate bread prepared in comparative example 5, recorded as E. The subjects fasted for 8 hours before eating.

[0060] 1.2 Sample preparation Take frozen bread of different groups, let it stand at room temperature for 10 minutes, and heat it in a microwave oven for 30 seconds. Put 5 samples in equal amounts on a plate and number them.

[0061] 1.3. Human blood sugar level test After fasting for 8 hours, rinse your mouth, draw blood from your fingertips, and use a handheld blood glucose meter to measure the fasting blood glucose level of the subjects. The subjects eat bread (groups A, B, C, D, and E) with 50g of carbohydrates, sit quietly for 2 hours, and are strictly prohibited from eating other foods during the test. The fasting blood glucose level is recorded as 0min, and the blood glucose levels are measured at 30min, 60min, and 120min after the meal, starting from the time of eating the first bite of bread.

[0062] 1.4. Calculation of GI values ​​of breads of different groups in human blood sugar test According to the changes in blood glucose levels 2 hours after a meal, the blood glucose response curve is drawn by subtracting the fasting blood glucose value from the blood glucose value at a certain time, and the GI value is calculated using formula 1-1.

[0063] GI= ×100 (1-1) 2) Experimental results 2.1. Human blood sugar test results Figure 3 The results of human blood sugar test at 0h-2h after eating different groups of bread. As can be seen from the figure, at 0min-30min, compared with the blank control group D, the blood sugar values ​​of groups A, B, C, and E increased slowly; at the 30min blood sugar peak, B<E<A<C<D group. At 0min-120min, compared with the blank control group D, the blood sugar values ​​of the other four groups decreased slowly, and the group with BX-259 postbiotics + sugarcane polyphenols (group B, corresponding to Example 3) decreased the most slowly, and the decline trend was also slower than that of the sugarcane polyphenols group (group C) and the postbiotics group (group A) alone. In summary, the addition of probiotics and postbiotics can reduce the blood sugar level of the human body, and the combination of BX-259 postbiotics and sugarcane polyphenols has a more significant effect on reducing human blood sugar.

[0064] 2.2 GI values ​​of different groups of bread in human blood sugar test Table 3 shows the GI values ​​of different breads calculated based on the human blood glucose response curve 2 hours after a meal. After calculation, the GI values ​​of the following five groups of bread, A, B, C, D, and E, are 45.26±10.12, 35.87±8.68, 62.41±12.51, 79.12±6.24, and 53.25±6.17, respectively. According to European standards, different breads are classified as follows: Bread in group D is a high GI food, bread in group C is a medium GI food, and bread in groups A, B, and E is a low GI food, and the GI values ​​of groups A and B are lower than those of group E. The above results show that the BX-259 postbiotic can reduce the risk of diabetes in the human body and improve the blood sugar levels of diabetic patients and pre-diabetic people.

[0065] Table 3 GI values ​​of bread in different groups in human blood sugar test

[0066] Note: The same letters in the same column indicate no significant difference (P>0.05), and different letters indicate significant difference (P<0.05).

[0067] Effect Example 3: Analysis of the texture characteristics of bread in different groups The five groups of bread in Effect Example 2 were placed in a microwave oven for 30 seconds, cut into even-sized bread pieces (length, width, and height of approximately 4 cm each), placed on the stage under the probe range of the texture analyzer, and texture tests were performed on hardness, elasticity, chewiness, etc. The test parameters are as follows: The TPA mode was selected, the probe was a PR / 36 cylindrical probe, the start and return measurement method was adopted, the trigger force was 5g, the speed before, during and after the measurement was 1mm / s respectively, and the compression was 50% of the original height. The same sample was subjected to 5 parallel experiments, and the results are shown in Table 4. The results showed that the bread hardness, adhesiveness and chewiness of groups A, B and E were lower than those of groups C and D, and the elasticity, cohesion and recovery were significantly higher than those of groups C and D. The results showed that probiotic postbiotics can increase the elasticity and recovery of bread, improve the fluffiness of bread, increase the fluffiness rate, make it taste better and more stable, and the effect of BX-259 postbiotics is more significant.

[0068] Table 4 Texture characteristics of bread in different groups Group Hardness (g) elasticity Cohesion Stickiness Chewability Responsiveness A <![CDATA[1629.47±317.24 bc ]]> <![CDATA[2.00±0.06 a ]]> <![CDATA[0.86±0.05 a ]]> <![CDATA[1362.96±98.77 c ]]> <![CDATA[1616.36±204.55 b ]]> <![CDATA[0.55±0.01 a ]]> B <![CDATA[1587.00±301.40 c ]]> <![CDATA[1.96±0.02 a ]]> <![CDATA[0.84±0.07 a ]]> <![CDATA[1425.32±143.99 c ]]> <![CDATA[1637.36±325.67 b ]]> <![CDATA[0.51±0.04 a ]]> C <![CDATA[2225.89±204.74 a ]]> <![CDATA[0.84±0.01 c ]]> <![CDATA[0.68±0.06 b ]]> <![CDATA[1651.89±113.24 ab ]]> <![CDATA[1847.88±55.81 a ]]> <![CDATA[0.30±0.02 c ]]> D <![CDATA[2264.96±222.05 a ]]> <![CDATA[0.81±0.03 c ]]> <![CDATA[0.63±0.04 b ]]> <![CDATA[1704.57±42.72 a ]]> <![CDATA[1821.41±152.14 a ]]> <![CDATA[0.27±0.01 d ]]> E <![CDATA[1912.17±101.20 b ]]> <![CDATA[1.81±0.05 b ]]> <![CDATA[0.79±0.05 a ]]> <![CDATA[1511.35±71.26 b ]]> 1724.16±221.81a <![CDATA[0.48±0.03 b ]]> Note: The same letters in the same column indicate no significant difference (P>0.05), and different letters indicate significant difference (P<0.05).

[0069] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A strain of Bifidobacterium animalis subsp. lactis ( Bifidobacterium animalis subsp. lactis ) BX-259, characterized in that The deposit number is CGMCC No.27838.

2. A bacterial agent, characterized in that It comprises the animal Bifidobacterium lactis subspecies BX-259 described in claim 1.

3. Use of the animal Bifidobacterium lactis subspecies BX-259 according to claim 1 in the preparation of postbiotics for lowering blood sugar.

4. A postbiotic capable of lowering the glycemic index of a human body, characterized in that: The postbiotics include the inactivated bacteria or metabolites of the animal Bifidobacterium lactis subspecies BX-259 according to claim 1.

5. The postbiotic according to claim 4, characterized in that The metabolites include any one or more of lactic acid, citric acid, tartaric acid, malic acid, benzoic acid, succinic acid, 4-hydroxyphenyllactic acid, oxalic acid, short-chain fatty acids, amino acids and antimicrobial peptides.

6. A method for preparing postbiotics, characterized in that: The method comprises the following steps: inoculating the animal Bifidobacterium lactis subspecies BX-259 described in claim 1 into a feed liquid, adding lactase, fermenting at a constant temperature, adding or not adding auxiliary materials after stopping the fermentation, then preheating, homogenizing, and finally inactivating.

7. The preparation method according to claim 6, characterized in that: The feed liquid comprises full-fat soybean powder, skim milk powder, sodium citrate and purified water.

8. The preparation method according to claim 6, characterized in that: Before the inactivation, the total viable count of the animal Bifidobacterium lactis subspecies BX-259 is ≥3.0×10 10 CFU / g.

9. Use of the animal Bifidobacterium lactis subsp. BX-259 according to claim 1, the bacterial agent according to claim 2, or the postbiotic according to claim 4 in the preparation of a blood sugar regulating product.

10. A product comprising the animal Bifidobacterium lactis subsp. BX-259 according to claim 1 or the bacterial agent according to claim 2 or the postbiotic according to claim 4, characterized in that: The product is food, health product or medicine.

11. The product according to claim 10, characterized in that The health care product is used for assisting in lowering blood sugar.

12. The product according to claim 10, characterized in that The food comprises bread, cake or biscuits.

13. The product according to claim 10, characterized in that The food is bread, and the components of the bread also include black barley whole wheat flour, oat flour, quinoa flour, sugarcane polyphenols, egg liquid, sorbitol liquid, xylitol and purified water.

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