Method for improving polyphenol content and lipid-lowering capacity of highland barley bran through synergistic fermentation of bacteria and enzymes

Abstract

The invention discloses a method for improving the polyphenol content and lipid-lowering capacity of highland barley bran through synergistic fermentation of bacteria and enzymes, and relates to the technical field of biological medicines. The method comprises the following steps: preparing highland barley bran, stabilizing, inoculating aspergillus oryzae and cellulase, adding sterile water, uniformly stirring, fermenting, drying, and crushing to obtain the highland barley bran fermented by bacteria and enzymes. Through the synergistic effect of bacteria and enzymes, the polyphenol content of the highland barley bran is remarkably increased, the lipid metabolism adjusting capacity and the lipid lowering effect of the highland barley bran are enhanced, and the problems of low polyphenol release efficiency, long fermentation period and the like in the prior art are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of biomedicine, and in particular to a method for improving the polyphenol content and lipid-lowering ability of highland barley bran through bacterial and enzyme-cooperative fermentation. Background Art

[0002] In modern society, people's dietary structure continues to change, and the problem of obesity is becoming increasingly serious, becoming one of the key factors threatening human health. Plant-derived phenolic compounds have been proven to be effective natural pancreatic lipase inhibitors. The methods for enriching phenolic substances in cereals are mainly divided into stress metabolism method, growth metabolism method and microbial fermentation method. In the existing technology, the total phenol content in highland barley can be increased by ultrasonic treatment, but excessive ultrasonication will lead to the degradation of phenolic substances. In addition, technicians have found that the total polyphenol content of quinoa can be increased by optimizing the germination conditions, but the germination process requires precise control of temperature, humidity and time conditions. Too long soaking time and too high humidity will lead to a decrease in water-soluble phenolic substances in the cereals, and too long germination time will cause the cereals to mold.

[0003] Microbial fermentation technology mostly relies on a single bacterial species, but this often leads to a long fermentation cycle, easy loss of active ingredients, and inability to effectively release bound polyphenols. In the existing technology, the bacterial enzyme synergistic fermentation technology mostly focuses on the changes in the nutritional quality of grains, such as using bacterial enzyme synergistic fermentation to improve the quality of rapeseed meal. Specifically, the crude protein content, small peptide content and reducing sugar content of rapeseed meal are increased through bacterial enzyme synergistic treatment. As a low-fat grain, highland barley, its processed by-product highland barley bran, contains phenolic substances with potential lipid-lowering activity. However, the current utilization of highland barley bran is extremely single, and most of it is only used to make animal feed. There are no reports on the scheme of using bacterial enzyme synergistic fermentation to treat highland barley bran to enhance its lipid-lowering activity. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a method for improving the polyphenol content and lipid-lowering ability of highland barley bran through bacterial enzyme-synergistic fermentation, which significantly improves the polyphenol content of highland barley bran, enhances its ability to regulate lipid metabolism and lipid-lowering effect, and effectively solves the problems of low polyphenol release efficiency and long fermentation cycle in the prior art.

[0005] To achieve the above object, the present invention solves the technical problem by adopting a technical solution of providing a method for improving the polyphenol content and lipid-lowering ability of highland barley bran by synergistic fermentation with bacterial enzymes, comprising the following steps: S1, washing highland barley grains, grinding them after soaking to obtain highland barley bran, and then baking them to obtain stabilized highland barley bran; S2, after sterilizing the stabilized highland barley bran obtained in step S1, inoculating Aspergillus oryzae and cellulase simultaneously to obtain a fermentation medium, then adding sterilized water, stirring and fermenting, then drying and pulverizing to obtain bacterial enzyme collaborative fermentation of highland barley bran.

[0006] Furthermore, in step S1, the highland barley is washed with purified water and the moisture content is adjusted to 15-25%.

[0007] Furthermore, in step S1, the immersion is carried out at room temperature for 8-10 hours.

[0008] Furthermore, in step S1, baking is performed at 110-120° C. for 5-10 min.

[0009] Furthermore, in step S1, baking is performed at 120° C. for 7 min.

[0010] Furthermore, in step S2, sterilization is performed at 121-122° C. for 20-21 min.

[0011] Furthermore, in step S2, sterilization is performed at 121° C. for 20 min.

[0012] Furthermore, in step S2, the inoculum amount of Aspergillus oryzae is 0.75-1.25%.

[0013] Furthermore, in step S2, the inoculation amount of Aspergillus oryzae is 1%.

[0014] Furthermore, in step S2, the inoculation amount of cellulase is 0.25-0.5%.

[0015] Furthermore, in step S2, the inoculation amount of cellulase is 0.5%.

[0016] Furthermore, in step S2, the mass volume ratio of the fermentation substrate to the sterile water is 1-3 g:0.5-1.5 mL.

[0017] Furthermore, in step S2, the mass volume ratio of the fermentation substrate to the sterile water is 2 g:1 mL.

[0018] Furthermore, in step S2, the fermentation is carried out at a constant temperature and humidity of 34-36° C. and a humidity of 74-76% for 20-30 hours.

[0019] Furthermore, in step S2, the fermentation was carried out at a constant temperature and humidity of 35° C. and 75% humidity for 24 h.

[0020] Furthermore, in step S2, drying is performed at 55-65°C.

[0021] Furthermore, in step S2, drying is performed at 60°C.

[0022] The present invention has the following beneficial effects: 1. The present invention adopts the method of bacterial enzyme synergistic fermentation, and synergistically applies Aspergillus oryzae and cellulase to the fermentation of highland barley bran. Through the dual action of microorganisms and enzymolysis, the cell wall structure of highland barley bran is broken, the bound polyphenols are released, and the content of free phenolic acids is significantly increased. By optimizing the bacterial enzyme ratio and process, the problems of low polyphenol release efficiency and long fermentation cycle in the prior art are solved, and the gap in the bacterial enzyme synergistic fermentation treatment to improve the lipid-lowering activity of highland barley bran is filled, providing an efficient solution for the high-value functional application of highland barley bran. Bacterial enzyme synergistic fermentation can significantly release bound polyphenols, increase the total free phenolic acid content by 4.82 times, of which ferulic acid and caffeic acid increase by 19.99 times and 24.65 times respectively, and change the composition of free phenolic acids. The present invention realizes the efficient release of functional components of highland barley bran and the comprehensive improvement of lipid-lowering activity through the innovative application of bacterial enzyme synergistic fermentation technology. Compared with existing technologies, it has significant advantages in polyphenol bioavailability, lipid metabolism regulation, intestinal flora control, etc., can provide a scientific basis for the development of functional foods, and has great academic value and industrialization potential.

[0023] 2. The bacterial enzyme synergistic fermentation of highland barley bran prepared by the present invention has a significant effect in regulating lipid metabolism, including weight control, blood lipid regulation, liver protection and fat accumulation inhibition. High-fat diet mice fed with the bacterial enzyme synergistic fermentation of highland barley bran prepared by the present invention showed lower body weight and lower blood lipid and blood sugar levels, and their weight gain decreased by 30.14%, and total cholesterol, triglyceride and low-density lipoprotein cholesterol levels decreased by 17.78%, 28.66% and 23.78% respectively. Fasting blood glucose value and area under the glucose tolerance curve decreased by 35.38% and 24.94% respectively, which is more conducive to improving the body's metabolic capacity of glucose. In addition, feeding bacterial enzyme synergistic fermentation of highland barley bran can make the liver cell morphology of mice caused by high-fat diet to recover normal, and intracellular vacuoles and fat droplets significantly reduce, so that the TC and TG levels of the mouse liver are restored to normal. Furthermore, it reduced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels by 13.03% and 37.83%, respectively, demonstrating a better repair effect on liver damage and mitigating the severity of the injury. Fermentation of highland barley bran with bacterial enzymes significantly improved hepatic steatosis in mice fed a high-fat diet, reducing fat accumulation, preventing white fat hypertrophy, shrinking the area of ​​epididymal adipocytes, and improving pathological conditions.

[0024] 3. The bacterial enzyme prepared by the present invention and the synergistic fermentation of highland barley bran can significantly improve the richness of the intestinal flora of mice fed a high-fat diet and regulate the structure of the intestinal flora. The ratio of Firmicutes / Bacteroidetes is reduced by 58.77%, while the butyric acid level is increased by 30.68%, and the butyric acid level is reduced, which is of great significance for maintaining the balance of intestinal flora, regulating lipid metabolism, and preventing and treating diseases related to abnormal lipid metabolism. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The effect of different Aspergillus fermentation on the free phenol content of highland barley bran; Figure 2 The effect of different bacterial enzymes on the free phenol content in highland barley bran; Figure 3 The effect of bacterial enzyme-co-fermented highland barley bran on the body weight of mice; Figure 4 The effect of bacterial enzyme-co-fermented highland barley bran on lipid metabolism in mice; Figure 5 is the fasting blood glucose of mice in each group; Figure 6 is the area under the glucose tolerance curve of mice in each group; Figure 7 This is the H&E staining picture of liver; Figure 8 This is the liver oil red O staining picture; Figure 9 is the liver TG and TC content; Figure 10 Serum AST and ALT levels; Figure 11 The results of fat weight of mice in each group Figure 12 The results of white fat / body weight of mice in each group; Figure 13 is the area of ​​white adipocytes in each group of mice; Figure 14 The effect of bacterial enzyme synergistic fermentation of highland barley bran on the expression of lipid metabolism-related genes in mice; Figure 15 The level of mouse intestinal flora; Figure 16 are Firmicutes, Bacteroidetes, Actinobacteria and F / B ratio; Figure 17 The top 10 bacterial genera with differences between HFD and HFD-FB; Figure 18 The top 10 bacterial genera with differences between HFD and HFD-UB. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below. The examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In the examples, where specific conditions are not specified, conventional conditions or manufacturer-recommended conditions were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0027] Example 1 A method for improving the polyphenol content and lipid-lowering ability of highland barley bran through bacterial and enzyme-cooperative fermentation comprises the following steps: S1, take 100 g highland barley grains, wash with pure water and adjust the moisture content of highland barley to 20%, grind to obtain highland barley bran after soaking for 9 hours at room temperature, and then bake at 120 ° C for 7 min to obtain stabilized highland barley bran; S2, the highland barley bran of step S1 gained stabilization is inoculated with aspergillus oryzae and cellulase simultaneously after 121 ℃ of sterilizations 20 min, the inoculum size of above-mentioned aspergillus oryzae is 1%, and the inoculum size of above-mentioned cellulase is 0.5%, obtain fermentation medium, then add 60 mL sterilized water, after stirring, ferment at constant temperature and humidity for 24 h under the condition of 35 ℃, humidity is 75%, then in 60 ℃ of dryings and pulverize, obtain bacterial enzyme collaborative fermentation highland barley bran.

[0028] Example 2 A method for improving the polyphenol content and lipid-lowering ability of highland barley bran through bacterial and enzyme-cooperative fermentation comprises the following steps: S1, take 100 g highland barley grains, wash with pure water and adjust the moisture content of highland barley to 15%, grind to obtain highland barley bran after soaking for 8 hours at room temperature, and then bake at 110 ° C for 5 min to obtain stabilized highland barley bran; S2, the highland barley bran of step S1 gained stabilization is inoculated with aspergillus oryzae and cellulase simultaneously after 121 ℃ of sterilizations 20 min, the inoculum size of above-mentioned aspergillus oryzae is 0.75%, and the inoculum size of above-mentioned cellulase is 0.25%, obtain fermentation medium, then add 55 mL sterilized water, after stirring, ferment at constant temperature and humidity for 20 h under the condition of 34 ℃, humidity is 74%, then in 55 ℃ of dryings and pulverize, obtain bacterial enzyme collaborative fermentation highland barley bran.

[0029] Example 3 A method for improving the polyphenol content and lipid-lowering ability of highland barley bran through bacterial and enzyme-cooperative fermentation comprises the following steps: S1, take 100 g of highland barley grains, wash them with pure water and adjust the moisture content of highland barley to 25%, soak them at room temperature for 10 h, grind them to obtain highland barley bran, and then bake them at 115 ° C for 10 min to obtain stabilized highland barley bran; S2, after the highland barley bran of step S1 is sterilized at 121 ℃ for 20 min, inoculate Aspergillus oryzae and cellulase simultaneously, the inoculum amount of above-mentioned Aspergillus oryzae is 1.25%, the inoculum amount of above-mentioned cellulase is 0.4%, obtain fermentation matrix, then add 50 mL sterilized water, stir evenly at 36 ℃, humidity is constant temperature and humidity fermentation under the condition of 76% for 30 h, then dry and pulverize at 60 ℃, obtain bacterial enzyme collaborative fermentation highland barley bran. The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, only 1% Aspergillus oryzae is inoculated.

[0030] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, only 1% Aspergillus niger was inoculated.

[0031] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, only 1% white Aspergillus was inoculated.

[0032] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, 1% Aspergillus oryzae and 0.5% protease were inoculated.

[0033] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in Comparative Example 5, 1% Aspergillus oryzae, 0.25% cellulase and 0.25% protease were inoculated.

[0034] Test Example 1 The free phenol content in the highland barley bran fermented by the bacterial enzymes prepared in Example 1, Comparative Example 1 and Comparative Example 2 was measured, and the unfermented highland barley bran was used as a control. The results are as follows: Figure 1 As shown, Figure 1 In the present invention, untreated is unfermented highland barley bran, 1% Aspergillus oryzae is the result of Comparative Example 1, 1% Aspergillus niger is the result of Comparative Example 2, and 1% Aspergillus kawachii is the result of Comparative Example 3.

[0035] Depend on Figure 1 It can be seen that the free phenol content of unfermented bran is 6.50 mg GAE / g DW, while the free phenol content of the fermented sample increased significantly. After fermentation by Aspergillus oryzae, Aspergillus niger and Aspergillus kawachii, the free phenol content of highland barley bran was 9.11, 8.92 and 8.76 mg GAE / g DW, respectively. This shows that fermentation by the three types of Aspergillus can significantly increase the free phenol content of highland barley bran ( P <0.05), among which Aspergillus oryzae had the best fermentation effect.

[0036] Test Example 2 The free phenol content in the highland barley bran fermented by the bacterial enzymes prepared in Example 1, Comparative Example 1, Comparative Example 4 and Comparative Example 5 was measured. The results are as follows: Figure 2 As shown, Figure 2 1% Aspergillus oryzae is the result of Comparative Example 1, 1% Aspergillus oryzae + 0.5% cellulase is the result of Example 1, 1% Aspergillus oryzae + 0.5% protease is the result of Comparative Example 4, and 1% Aspergillus oryzae + 0.25% cellulase + 0.25% protease is the result of Comparative Example 5.

[0037] Depend on Figure 2 It can be seen that compared with the fermentation of Aspergillus oryzae alone, the addition of cellulase, protease or both can significantly increase the content of free phenols in highland barley bran ( P <0.05), the free phenol contents of 1% Aspergillus oryzae + 0.5% cellulase, 1% Aspergillus oryzae + 0.5% protease, and 1% Aspergillus oryzae + 0.25% cellulase + 0.25% protease were 10.43, 9.77, and 9.35 mg GAE / g DW, respectively. It can be seen that the addition of 1% Aspergillus oryzae + 0.5% cellulase has the best effect. Compared with single Aspergillus oryzae fermentation, the present invention increases the free phenol content in highland barley bran by 14.49% through the synergistic fermentation of Aspergillus oryzae and cellulase.

[0038] Test Example 3 The free phenol content of the unfermented highland barley bran and the highland barley bran fermented with the bacterial enzyme prepared in Example 1 was measured, and the results are shown in Table 1.

[0039] Table 1 Free phenol content

[0040] Note: Different small letter superscripts in the same row indicate significant differences in the data ( P <0.05).

[0041] As shown in Table 1, the total free phenolic acid content of untreated highland barley bran was 125.19 μg / g DW, with 3,4-dihydroxybenzoic acid, ferulic acid, and vanillic acid being the highest. These three phenolic compounds accounted for 45.00%, 16.93%, and 11.67% of the total free phenolic acid content, respectively. After bacterial-enzyme co-fermentation, the total free phenolic acid content in highland barley bran reached 728.53 μg / g DW, with ferulic acid, 3,4-dihydroxybenzoic acid, and vanillic acid remaining the primary free phenolic acids. These three phenolic compounds accounted for 61.05%, 12.02%, and 10.15% of the total free phenolic acid content, respectively. After bacterial-enzyme co-fermentation, the total free phenolic acid content of highland barley bran increased by 4.82-fold. With the exception of 4-hydroxybenzoic acid, benzoic acid, phthalic acid, and trans-cinnamic acid, all other free phenolic acids showed significant increases. Especially caffeic acid and ferulic acid, the contents of the two increased by 24.65 and 19.99 times respectively.

[0042] Test Example 4 Mice were divided into a normal diet group (NCD), a high-fat diet group (HFD), a high-fat diet group fed with unprocessed highland barley bran (HFD-UB), and a high-fat diet group fed with bacterial enzyme-co-fermented highland barley bran (HFD-FB). The feed formulas are shown in Table 2. In HFD-UB and HFD-FB, the addition of unprocessed highland barley bran and bacterial enzyme-co-fermented highland barley bran accounted for 15% of the total feed.

[0043] Table 2 Feed formula

[0044] The indoor environment is controlled by an independent air-conditioning fan system, and the room is well ventilated, with room temperature of 22-25°C and relative humidity of 65-70%. The laboratory environment is kept clean and sanitary, and mice are free to eat and drink. After one week of adaptive feeding, all groups of mice are fed according to the corresponding experimental groups for 12 weeks. The mice are weighed at the same time every week. After the intervention, the mice are fasted for one day, blood is collected from the eye sockets, and serum is collected after centrifugation for blood biochemical analysis. The fasting blood glucose, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations of the mice are measured. The mice are then killed by cervical dislocation, dissected, and the liver and adipose tissue of the mice are collected to measure the test indicators such as the body fat ratio and cell area of ​​epididymal adipocytes. The weight changes of mice are as follows Figure 3 The results of blood lipid related tests are shown in Figure 4 Blood sugar related test results are shown as follows. Figure 5 and Figure 6 As shown, Figure 5 is the fasting blood glucose of mice in each group, Figure 6The area under the glucose tolerance curve is shown in Table 2. Figure 7-10 shown. Figure 7 H&E staining of liver. Figure 8 This is the liver oil red O staining picture. Figure 9 is the content of liver TG and TC, Figure 10 The serum AST and ALT levels are shown in Table 2. The effects of bacterial enzyme-co-fermented highland barley bran on white fat accumulation and fat hypertrophy in mice fed a high-fat diet are shown in Table 2. Figure 11-13 As shown, Figure 11 The results of fat weight of mice in each group are shown in Table 1. Figure 12 The results of white fat / body weight of mice in each group are shown in Table 1. Figure 13 =The area of ​​white fat cells in each group of mice. Figure 14 As shown, Figure 14 Among them, SREBP-2 is sterol regulatory element binding protein 2, HMGCR is 3-hydroxy-3-methylglutaryl-CoA reductase, FAS is fatty acid synthase, CPT-1 is carnitine palmitoyltransferase 1, PPAR-γ is peroxisome proliferator-activated receptor γ, CD36 is cluster of differentiation antigen 36, SREBP-1C is sterol regulatory element binding protein 1c, and PPAR-α is peroxisome proliferator-activated receptor α.

[0045] Depend on Figure 3 It can be seen that after 12 weeks of high-fat diet feeding, the body weight of mice in the HFD group increased significantly ( P <0.05). Further comparative analysis of different intervention groups revealed that, compared with the HFD group, the weight gain of the high-fat diet mice group (HFD-FB) fed with the bacterial enzyme-co-fermented highland barley bran prepared by the present invention was reduced by 30.14%, which was better than that of the group fed with unfermented highland barley bran (HFD-UB, reduced by 14.44%). This indicates that the bacterial enzyme-co-fermented highland barley bran prepared by the present invention has a better effect on controlling weight.

[0046] Depend on Figure 4 It can be seen that the bacterial enzyme prepared by the present invention and the synergistic fermentation of highland barley bran have a more positive effect on improving blood lipid status. The TC, TG and LDL-C levels in the serum of the HFD-FB group were reduced by 17.78%, 28.66% and 23.78%, respectively, which is better than that of the HFD-UB group (TC decreased by 10.03%, TG decreased by 15.85%, and LDL-C decreased by 2.44%).

[0047] Depend on Figure 5 and Figure 6It can be seen that compared with the HFD group, the fasting blood glucose value and area under the glucose tolerance curve of the HFD-FB group decreased by 35.38% and 24.94%, respectively, which is better than the HFD-UB group (fasting blood glucose value decreased by 21.32%, and the area under the glucose tolerance curve decreased by 18.54%), and is more helpful in improving the body's ability to metabolize glucose.

[0048] Depend on Figure 7-10 It was found that a high-fat diet causes a large amount of fat accumulation in the liver cells of mice. After feeding the mice unfermented highland barley bran and highland barley bran fermented with bacterial enzymes, the liver cell morphology of the mice returned to normal, with a significant decrease in intracellular vacuoles and lipid droplets. The restorative effect of HFD-FB was even more pronounced. The liver TC and TG levels also showed that bran intervention restored the TC and TG levels in the mouse liver to normal. In addition, the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HFD-FB group decreased by 13.03% and 37.83%, respectively, which was superior to the AST (reduction of 2.40%) and ALT (reduction of 12.77%) levels in the HFD-UB group, demonstrating a better repair effect on liver damage and reduced the severity of the damage.

[0049] Depend on Figure 11-13 It can be seen that a high-fat diet causes significant hypertrophy of epididymal adipocytes in mice and excessive accumulation of lipids in the cells. Compared with the HFD group, the fat accumulation in the epididymis and mesentery of the HFD-UB and HFD-FB groups showed a significantly reduced trend. Correspondingly, the body fat ratio and cell area of ​​epididymal adipocytes in the HFD-UB and HFD-FB groups also showed a significant downward trend, and the effect of the HFD-FB group was more obvious. The body fat ratio of epididymal adipocytes in the HFD-FB group decreased by 19.53% (the HFD-UB group decreased by 5.32%), and the cell area decreased by 47.36% (the HFD-UB group decreased by 25.11%). This shows that the bacterial enzyme-co-fermented highland barley bran prepared by the present invention has a better effect in preventing fat accumulation and white blood cell hypertrophy.

[0050] Depend on Figure 14 It can be seen that the bacterial enzyme prepared by the invention synergistically ferments highland barley bran by downregulating the levels of SREBP-2, SREBP-1C, HMGCR, FAS, CD36 and PPAR-γ, and upregulating the expression of CPT-1 and PPAR-α genes, thereby effectively inhibiting the formation of liver fat and the synthesis of cholesterol, and promoting the decomposition of lipids.

[0051] Test Example 5 Mice were divided into a normal diet group (NCD), a high-fat diet group (HFD), a high-fat diet group fed with unprocessed highland barley bran (HFD-UB), and a high-fat diet group fed with bacterial enzyme-co-fermented highland barley bran (HFD-FB). The feed formula was the same as in Table 2. The indoor environment was well ventilated using an independent air-conditioning fan system, with a room temperature of 22-25°C and a relative humidity of 65-70%. The laboratory environment was kept clean and hygienic, and mice had free access to food and water. After one week of adaptive feeding, all groups of mice were housed according to the corresponding experimental group for 10 weeks. In the 10th week, abdominal massage was used to stimulate mice to defecate, and the defecation was collected. 16S rRNA gene sequencing was used to detect the species composition and relative abundance of the intestinal flora at the phylum and genus levels, the Firmicutes / Bacteroidetes (F / B) ratio was calculated, and the content of short-chain fatty acids (SCFA) in the mouse feces was determined. Figure 15 and Figure 16 As shown, Figure 15 The level of mouse intestinal flora, Figure 16 The values ​​of Firmicutes, Bacteroidetes, Actinobacteria and F / B ratio are shown in Table 2. Figure 17 and Figure 18 As shown, Figure 17 Here are the top 10 bacterial species with differences between HFD and HFD-FB. Figure 18 The top 10 bacterial genera with differences between HFD and HFD-UB.

[0052] Depend on Figure 15 and Figure 16 At the phylum level, three dominant bacterial groups were found in each sample group: Firmicutes, Bacteroidota, and Actinobacteriota. Compared to the HDF group, the relative abundance of Firmicutes decreased by 11.37% in the HDF-FB group (7.92% in the HDF-UB group), while the relative abundance of Bacteroidetes increased by 114.93% (54.66% in the HDF-UB group). This significantly reduced the Firmicutes / Bacteroidetes (F / B) ratio (58.77% in the HDF-FB group and only 40.47% in the HDF-UB group). A lower F / B ratio may reduce the risk of obesity and hyperlipidemia.

[0053] Depend on Figure 17 and Figure 18It can be seen that there are 10 key bacterial genera with significant differences between the HFD and HFD-UB and HFD-FB groups. The synergistic fermentation of bran with bacterial enzymes can significantly increase the relative abundance of Dubosiella and unclassified Clostridia UCG-014 (norank_o_Clostridia_UCG-014), and reduce the relative abundance of Romboutsia, Colidextribacter and Streptococcus.

[0054] Test Example 6 The effect of the bacterial enzyme prepared by the present invention on the content of short-chain fatty acids in the fermented highland barley bran was detected, and the results are shown in Table 3.

[0055] Table 3 Effect of bran on the content of short-chain fatty acids in feces

[0056] Note: Different small letter superscripts in the same row indicate significant differences in the data ( P <0.05).

[0057] As shown in Table 3, the synergistic fermentation of highland barley bran with bacterial enzymes significantly increased the butyric acid level in the feces of HFD mice (the HDF-FB group increased by 30.68%, and the HDF-UB group increased by 1.98%), and reduced the acetic acid (the HDF-FB group decreased by 33.22%, and the HDF-UB group decreased by 17.20%), isobutyric acid (the HDF-FB group decreased by 48.98%, and the HDF-UB group decreased by 5.71%), and isovaleric acid (the HDF-FB group decreased by 57.17%, and the HDF-UB group decreased by 36.66%).

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for increasing the polyphenol content and lipid-lowering ability of highland barley bran by synergistic fermentation with bacterial enzymes, characterized in that: The following steps are involved: S1, washing highland barley grains, grinding them after soaking to obtain highland barley bran, and then baking them to obtain stabilized highland barley bran; S2, after sterilizing the stabilized highland barley bran obtained in step S1, inoculating Aspergillus oryzae and cellulase simultaneously to obtain a fermentation medium, then adding sterilized water, stirring and fermenting, then drying and pulverizing to obtain bacterial enzyme collaborative fermentation of highland barley bran.

2. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S1, the substrate is immersed at room temperature for 8-10 hours.

3. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S1, baking is carried out at 110-120° C. for 5-10 min.

4. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S1, the highland barley is washed with purified water and the moisture content is adjusted to 15-25%.

5. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, sterilize at 121-122° C. for 20-21 min.

6. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, the inoculum amount of Aspergillus oryzae is 0.75-1.25%.

7. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, the inoculation amount of cellulase is 0.25-0.5%.

8. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, the mass volume ratio of the fermentation substrate to the sterile water is 1-3 g:0.5-1.5 mL.

9. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, the fermentation is carried out at a constant temperature and humidity of 34-36° C. and 74-76% humidity for 20-30 h.

10. The method for improving the polyphenol content and lipid-lowering ability of highland barley bran by bacterial and enzyme synergistic fermentation as claimed in claim 1, characterized in that: In step S2, drying is performed at 55-65°C.

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