Brown algae extract for intestinal regulation

Abstract

The invention provides a brown algae extract for regulating intestinal tracts. The brown algae extract is prepared by the following steps: 1) strain fermentation: adopting bacillus subtilis, arthrobacter and pseudoalteromonas angustifolia; activating and enriching the strain, inoculating the strain to an alginic acid functional culture medium, and carrying out fermentation culture on the strain for 20-24 hours to obtain a strain fermentation broth; and 2) preparing an alginic acid extract: preparing a seaweed meal solution with the mass concentration of 8-12%, adding the strain fermentation liquor obtained in the step 1), and carrying out biological reaction at 30-35 DEG C for 28-32 hours. The brown algae extract provided by the invention is prepared by fermenting and purifying kelp powder. The two strains are matched, so that the high yield of effective components can be obtained. A mouse experiment is carried out on the obtained brown algae extract, and the experiment result shows that the abundance of beneficial bacteria in the intestinal tract can be improved through intervention of the brown algae extract in a low-dose group and a high-dose group, so that the immunity of the intestinal tract of the organism is improved.

Description

Technical Field

[0001] The invention belongs to the field of organic macromolecular compounds, and specifically relates to a brown algae extract and a preparation method and application thereof. Background Art

[0002] Kelp (Saccharina japonica) is a plant of the genus Laminariaceae, Laminariaceae, Phaeophyta, Phaeophyceae, and grows in seas with relatively low water temperatures. It is rich in a variety of active substances such as alginate, fucoxanthin, and brown algae starch. It is known as a natural health food and is a large algae with edible, medicinal, health, industrial, and agricultural values. Brown algae extract is a biologically active organic polymer extracted from seaweed. The structural characteristics of brown algae extracts, such as M / G, molecular weight, and degree of acetylation, directly affect their physical and chemical properties such as viscosity, gelation, and water solubility. Alginate is widely used in the field of food processing as a food additive such as a thickener, emulsifier, and quality improver. However, due to the large molecular weight, strong gelation and high viscosity of alginate (a method for testing the molecular weight and molecular weight distribution of alginate using high performance gel permeation chromatography, Zhang Ruixin et al., "Journal of Process Engineering", Issue 1, 2020: 99-107), it is not easily absorbed by the body, which limits its potential applications. The production and preparation methods of brown algae extracts are mainly chemical, physical and bio-enzymatic methods. Among them, bio-enzymatic hydrolysis technology uses enzymes such as alginate lyase, cellulase, protease, pectinase, and cell wall enzyme to effectively degrade brown algae to obtain brown algae extracts. The chemical composition of seaweed cell walls is significantly different from that of higher plant cell walls. Seaweed cell walls have a variety of seaweed polysaccharides, and their degradation requires bacteria that secrete cell wall enzymes.

[0003] Many strains can secrete enzymes to achieve enzymatic hydrolysis of brown algae. The fermentation broth of the strains contains more biologically active components; different types of strains produce different oligosaccharide structures and polymerization ranges, and some process conditions can also control the oligosaccharide content and different polymerization degrees. Proper selection of strains and fermentation conditions to obtain brown algae extracts with immune-enhancing functions is a very challenging research direction.

[0004] It is worth noting that, compared with existing natural active substances, brown algae extracts have shown outstanding effects in improving the structure of the host's intestinal flora, especially in increasing the abundance of beneficial bacteria of the genera Lactobacillus and Bifidobacterium, which are very important for human health, indicating that it has great development potential. Currently, there are few existing natural active substances that can stimulate the growth of two beneficial bacteria genera, Lactobacillus and Bifidobacterium, in the intestinal flora. Lactobacillus and Bifidobacterium are currently the most typical and most important beneficial bacteria genera in the human intestine. They can enhance the intestinal barrier, inhibit the colonization of pathogenic bacteria and reduce toxin levels in the human intestine, and have the effects of inhibiting the occurrence and development of cancer, improving the body's immunity, protecting the liver, relieving constipation, etc. Bifidobacterium longum is the most abundant bifidobacterium in the human intestine and one of the most widely used probiotics. It has many functions such as antagonizing pathogenic bacteria, regulating immune response, regulating sugar and lipid metabolism, and improving intestinal motility, and is certified as a safe and edible strain. The research results of this project show that brown algae extract is an important prebiotic for enhancing the two beneficial bacteria genera of Bifidobacterium and Lactobacillus, especially Bifidobacterium longum and Lactobacillus iners. Summary of the invention

[0005] In view of the shortcomings of the prior art, the first object of the present invention is to provide a brown algae extract for intestinal regulation.

[0006] The second object of the present invention is to provide the application of the brown algae extract.

[0007] The technical solution for achieving the above-mentioned purpose of the present invention is:

[0008] A brown algae extract for intestinal regulation, wherein the brown algae extract is prepared by the following steps:

[0009] 1) Bacterial fermentation: using one or more of Bacillus subtilis, Arthrobacter sp. and Pseudoalteromonas espejiana; activating and enriching the bacterial strains respectively, inoculating them into alginate functional medium, controlling the temperature at 28° C. to 30° C., controlling the pH at 6.5 to 8.0, fermenting and culturing the strains for 20 to 24 hours, and obtaining bacterial fermentation liquid;

[0010] 2) Preparation of alginic acid extract: prepare 8% to 12% seaweed powder solution, add the bacterial fermentation liquid obtained in step 1), carry out biological reaction at 30° C. to 35° C. for 24 to 36 hours, and obtain brown algae fermentation liquid.

[0011] Wherein, the brown algae extract is extracted from brown algae fermentation broth;

[0012] The effective ingredients in the brown algae extract account for 45 to 68% of the mass ratio; the effective ingredients include oligosaccharides formed by sugar chains formed by guluronic acid (G) with a degree of polymerization of 2 to 10, mannuronic acid (M) or a hybrid of the two connected by β-1,4 glycosidic bonds; and brown algae polysaccharides account for 25 to 40% of the mass ratio in the brown algae extract.

[0013] The brown algae extract contains alginate oligosaccharides with a polymerization degree of 2-6.

[0014] Among the strains used for fermentation, Bacillus subtilis is a GRAS strain included in the US FDA and is a food-grade microorganism. However, when the fermentation medium is prepared with seaweed powder, fermentation with Bacillus subtilis alone cannot achieve a good fermentation effect. It is preferred that Bacillus subtilis be used in combination with strains that can effectively degrade brown algae to achieve better fermentation and degradation effects.

[0015] A preferred technical solution of the present invention is that the bacterial species is a mixed bacterial species of Bacillus subtilis and Pseudoalteromonas espejiana at a bacterial count ratio of 1:0.5-1.

[0016] Wherein, the alginate functional medium in step 1) contains the following components in mass proportion: seaweed powder 3-5 g / L, trypsin 3-5 g / L, glucose 10 g / L, K2 HPO4 5-8 g / L, chloramphenicol 2-10 μg / mL, magnesium sulfate 1-2 g / L, ferrous sulfate 0.1-0.2 g / L, and the pH value is 6.5-7.0.

[0017] The pH value of the culture medium can be adjusted with 1M HCl, or other pH-adjusting agents known in the art. The seaweed powder used is obtained by drying and grinding kelp.

[0018] Wherein, in step 1), the temperature is controlled at 28°C to 30°C, the pH is controlled at 6.5 to 7.0, and the strain is fermented and cultured for 20 to 24 hours.

[0019] Wherein, in step 2), the mass ratio of the seaweed powder solution to the bacterial fermentation liquid is 100:4-5.

[0020] Preferably, in step 2), the biological reaction is carried out at 30°C to 35°C for 28 to 30 hours.

[0021] Furthermore, the preparation steps of the brown algae extract also include step 3) removing insoluble polysaccharides by centrifugal filtration, obtaining oligosaccharides with a degree of polymerization of 2 to 6 by membrane filtration, and spray-drying the obtained solution at 80 to 100° C. to obtain the brown algae extract.

[0022] The invention discloses an application of the brown algae extract in preparing an intestinal tract regulating functional food.

[0023] Wherein, the mass content of the brown algae extract in the intestinal tract regulating functional food is 0.4-3.6%.

[0024] The beneficial effects of the present invention are:

[0025] The brown algae extract proposed by the present invention is obtained by fermenting and purifying kelp powder. The combination of two strains can achieve a higher yield of effective ingredients. The preparation method proposes a fermentation and degradation process of seaweed powder, directly utilizes seaweed and achieves a better yield, while also reducing the cost of raw materials.

[0026] Animal experiments were conducted on the obtained brown algae extract, and the results showed that intervention with brown algae extract in the low-dose and high-dose groups could increase the abundance of beneficial bacteria in the intestines, especially the abundance of bifidobacteria and lactobacilli, thereby significantly improving the body's intestinal immunity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The UV spectrum of the product of Example 3 is shown in FIG.

[0028] Figure 2 The effect of brown algae extract on the α-diversity of intestinal flora in mice. Note: "*" indicates a significant difference between the two groups (P < 0.05).

[0029] Figure 3 The effect of brown algae extract on the β-diversity of intestinal flora in mice. Note: "*" indicates a significant difference between the two groups (P < 0.05).

[0030] Figure 4 The effect of brown algae extract on the level of intestinal flora in mice.

[0031] Figure 5 PLSA was used to analyze the effect of brown algae oligosaccharide brown algae extract on the genus levels of intestinal flora in mice.

[0032] Figure 6 The effect of brown algae extract on the species level of intestinal flora in mice.

[0033] Figure 7 PLSA was used to analyze the effect of brown algae extract on the species level of intestinal flora in mice.

[0034] Figure 8 FAPROTAX was used to analyze the effect of brown algae extract intervention on the intestinal flora function of mice. DETAILED DESCRIPTION

[0035] The following examples are used to illustrate the present invention but should not be used to limit the scope of the present invention.

[0036] The bacterial species used in the examples are commercially available Bacillus subtilis, with a deposit number of ATCC6633; Pseudoalteromonas espejiana, with a deposit number of ATCC29659; and Arthrobacter sp., with a deposit number of ATCC15584.

[0037] Seaweed powder: Dry and grind kelp, and pass through a 100-mesh sieve.

[0038] In the examples, unless otherwise specified, all means used are conventional techniques in the art; and all raw materials used are commercially available unless otherwise specified.

[0039] Example 1 Preparation of brown algae extract

[0040] 1) Bacterial fermentation: Bacillus subtilis was used as the bacterial strain, which was activated and enriched. The strain was inoculated into alginate functional medium, the temperature was controlled at 28°C-30°C, the pH was controlled at 7.0, and the strain was fermented for 24 hours to obtain bacterial fermentation liquid.

[0041] 2) Preparation of brown algae extract: Prepare a solution with a mass concentration of 12% with food-grade seaweed powder, add the bacterial fermentation liquid obtained in step 1), and carry out biological reaction at 30° C. to 35° C. for 30 hours to obtain brown algae fermentation liquid;

[0042] 3) removing insoluble polysaccharides by centrifugal filtration, obtaining oligosaccharides with a degree of polymerization of 2-6 by membrane filtration, and spray-drying the obtained solution at below 100° C. to obtain brown algae extract.

[0043] The alginic acid functional medium contains the following ingredients in mass ratio: 5 g / L food-grade seaweed powder, 5 g / L tryptone, 10 g / L glucose, 5 g / L K2HPO4, 2 μg / mL chloramphenicol, 1 g / L magnesium sulfate, 0.1 g / L ferrous sulfate, and a pH value of 6.5. The pH value is adjusted with 1 M HCl. The medium formula for strain activation and enrichment is the same as the alginic acid functional medium, with 20 g / L agar added.

[0044] The mass ratio of the food-grade seaweed powder solution to the bacterial fermentation liquid is 100:5.

[0045] It is known that the molecular weight of oligosaccharides with a degree of polymerization of 2 to 6 is 414.23Da to 1200Da. The type of filter membrane is selected according to the molecular weight range, and the content of oligosaccharides with a degree of polymerization of 2 to 6 in the obtained brown algae extract is 42.4%. The yield is 57.2%.

[0046] Bacillus subtilis has been reported to degrade alginate. When the fermentation medium is prepared with seaweed powder, fermentation with Bacillus subtilis alone cannot achieve a good fermentation effect, and the yield of effective ingredients is low. We selected a strain that has been reported to effectively degrade brown algae and used it in combination with Bacillus subtilis to achieve a better fermentation effect.

[0047] Example 2 Preparation of brown algae extract

[0048] 1) Bacterial fermentation: Bacillus subtilis and Arthrobacter sp. are used as bacterial strains; the bacterial strains are activated and enriched respectively. The bacterial count ratio is 1:1 and then inoculated into alginate functional medium, the temperature is controlled at 28°C to 30°C, the pH is controlled at 6.5 to 7.0, and the strains are fermented for 24 hours to obtain bacterial fermentation liquid. The culture medium is the same as in Example 1.

[0049] 2) Preparation of brown algae extract: prepare a 12% seaweed powder solution, add the bacterial fermentation liquid obtained in step 1), and carry out biological reaction at 30° C. to 35° C. for 30 hours to obtain brown algae fermentation liquid;

[0050] 3) removing insoluble polysaccharides by centrifugal filtration, selecting the type of filter membrane according to the molecular weight range, obtaining oligosaccharides with a degree of polymerization of 2 to 6 by membrane filtration, and spray drying the obtained solution at 90° C. to obtain a brown algae extract. The content of oligosaccharides with a degree of polymerization of 2 to 6 in the obtained brown algae extract is 52.4%.

[0051] The yield of the obtained product was 64.6%.

[0052] Example 3 Preparation of brown algae extract

[0053] 1) Bacterial fermentation: Bacillus subtilis and Arthrobacter sp. are used as bacterial strains; the bacterial strains are activated and enriched respectively. The bacterial strains are mixed in a bacterial count ratio of 1:1 and inoculated together in an alginate functional medium. The temperature is controlled at 28°C-30°C and the pH is controlled at 6.5-7.0. The strains are fermented and cultured for 24 hours to obtain bacterial fermentation liquid. The culture medium is the same as in Example 1.

[0054] 2) Preparation of brown algae extract: prepare a 12% seaweed powder solution, add the bacterial fermentation liquid obtained in step 1), and carry out biological reaction at 30° C. to 35° C. for 30 hours to obtain brown algae fermentation liquid;

[0055] 3) removing insoluble polysaccharides by centrifugal filtration, obtaining oligosaccharides with a degree of polymerization of 2-6 by membrane filtration, and spray-drying the obtained solution at 90° C. to obtain brown algae extract.

[0056] The yield was 68.9%. The obtained brown algae extract was detected by ultraviolet spectrum at 200-800 nm. The structure is shown in Figure 1 The oligosaccharides with a polymerization degree of 2 to 6 have a peak at 300 to 400 nm. The content of oligosaccharides with a polymerization degree of 2 to 6 in the brown algae extract is 66.8%, and the yield is 71.7%.

[0057] Example 4 Preparation of brown algae extract

[0058] 1) Bacterial fermentation: Bacillus subtilis and Arthrobacter sp. are used as bacterial strains, which are activated and enriched respectively. They are mixed in a bacterial count ratio of 1:0.5 and inoculated together in alginate functional medium. The temperature is controlled at 28°C-30°C and the pH is controlled at 6.5-7.0. The strains are fermented for 24 hours to obtain bacterial fermentation liquid.

[0059] 2) Preparation of brown algae extract: Prepare 12% seaweed powder solution, add the bacterial fermentation liquid obtained in step 1), carry out biological reaction at 30°C to 35°C for 30 hours, remove insoluble polysaccharides by centrifugal filtration, obtain oligosaccharides with a degree of polymerization of 2 to 6 by membrane filtration, spray dry the obtained solution at 90°C to obtain brown algae extract. The content of oligosaccharides with a degree of polymerization of 2 to 6 in the obtained brown algae extract is 65.4%.

[0060] The yield of the product was 70.2%.

[0061] Comparing Example 2 with Example 3, the effect of Bacillus subtilis combined with Pseudoalteromonas elsdenii is better than that of combined with Arthrobacter; comparing Example 3 with Example 4, the amount of Pseudoalteromonas elsdenii (Arthrobacter sp.) is reduced, and the content of oligosaccharides with a degree of polymerization of 2 to 6 is still higher than 65%. Considering the uncertainty of the safety of Pseudoalteromonas elsdenii to the human body, a mixture of Bacillus subtilis and Pseudoalteromonas elsdenii in a bacterial count ratio of 1:0.5 is preferred.

[0062] Test example

[0063] The brown algae extract prepared in Example 4 was used in the test example and was prepared into solutions of different concentrations using purified water.

[0064] Mouse toxicology experiment: The brown algae extract was gavaged at doses of 150, 300, and 600 mg / mL, and the mice were gavaged multiple times within 24 hours to observe the death of the mice. The experimental results showed that the highest solubility concentration of the brown algae extract was 600 mg / mL, and even at this dose, it would not cause toxic reactions in mice, indicating that the brown algae extract can be safely consumed.

[0065] Animal experiment: 40 male adult mice (8 weeks old) were randomly divided into 4 groups according to body weight, with 10 mice in each group. Group 1 was the control group, and groups 2-4 were intervention groups. They were given low, medium, and high doses (4, 12, and 36 mg / mL) of brown algae extract by gavage for 45 consecutive days, once a day. Mouse feces were collected, and total fecal microbial DNA was extracted. 16SrDNA high-throughput sequencing technology was used to analyze the diversity and differences of mouse intestinal flora.

[0066] Effect of brown algae extract on the diversity of intestinal flora in mice: α-diversity refers to the number of species in a community (richness) and the number and distribution of each species (uniformity). Both ACE and Chao 1 indexes are indices for measuring the abundance of flora. The results of α-diversity of intestinal flora in mice in the intervention groups with different doses of brown algae extract are as follows Figure 2 (Control in the figure is the control group, that is, the group without brown algae extract gavage) As shown, compared with the blank control group, both the high-dose group (36 mg / mL) and the low-dose group (4 mg / mL) showed significant differences from the control group (P<0.05), indicating that both high-dose and low-dose oligosaccharides will change the composition of the intestinal flora in mice. Combined with the subsequent flora structure analysis, it was found that the intake of oligosaccharides will directionally increase the abundance of some core bacterial genera.

[0067] β-diversity refers to the composition of the microbial community within each sample. The β-diversity of the intestinal flora of mice in the different brown algae extract intervention groups was compared using two dimensionality reduction analysis methods, non-metric multidimensional scaling analysis (NMDS) and principal coordinate analysis (PCoA). The results are as follows: Figure 3 There were significant differences among the different brown algae extract dosage groups (P<0.05), indicating that the intake of different doses of brown algae extract had different improvement effects on the composition of the intestinal flora of mice. Combined with the previous α-diversity analysis, it was found that the intake of brown algae extract changed the types and quantity of the intestinal flora of mice, and directed the increase in the number of some core bacterial species and the diversity within the genus.

[0068] Effects of brown algae extract on the composition of intestinal flora in mice: The intestinal flora is the most complex microecological system in the body, which is closely related to the body's immune stimulation, biological antagonism and nutritional metabolism. Based on the results of the intestinal flora diversity of mice in the above-mentioned different brown algae extract dose intervention groups, the effects of brown algae extract intervention on the composition of intestinal flora in mice were further analyzed at the genus level and species level.

[0069] (1) Analysis of intestinal flora structure at the genus level: The analysis of flora structure at the genus level is the most accurate depth that can be achieved by 16S sequencing, and it also more intuitively reflects the microscopic changes of the flora. Figure 4As shown in the figure, after the intervention of brown algae extract, it can be found that the beneficial bacteria represented by the two genera of Lactobacillus and Bifidobacterium have changed significantly and become the dominant genera. The experimental results show that brown algae extract is an important prebiotic for improving the two beneficial bacteria of Lactobacillus and Bifidobacterium.

[0070] pass Figure 5 The partial least squares analysis (PLSDA) in the data showed that the intestinal flora structure of mice in different brown algae extract intervention groups showed differences at the genus level, especially the high-dose group showed more significant differences compared with other groups, and the changes in Lactobacillus and Bifidobacterium had a higher contribution, that is, the high-dose brown algae extract had a more significant regulatory effect on beneficial bacteria.

[0071] (2) Analysis of intestinal flora structure at the species level: In the above genus-level structure analysis, it was found that the abundance of Lactobacillus and Bifidobacterium in the intestinal flora of mice in the high-dose group increased, and the data at the species level were further mined, such as Figure 6 As shown, it was found that Bifidobacterium longum and Lactobacillus iners were the species with the most significant changes in the two genera, so it is speculated that the brown algae extract has a directional stimulating effect on the growth of these two species.

[0072] pass Figure 7 The partial least squares analysis (PLSDA) in the data showed that the intestinal flora structure of mice in different brown algae extract intervention groups showed significant differences at the species level, especially in the high-dose group, indicating that high-dose brown algae extract increased the abundance of beneficial bacteria in the mouse intestine.

[0073] Effects of brown algae extract intervention on the function of intestinal flora in mice: Based on the above analysis of the abundance of flora and changes in bacterial species structure, the function of the intestinal flora of mice under the intervention of brown algae extract was further analyzed. Figure 8 The results showed that after intervention with brown algae extract, the intestinal flora of mice was significantly enhanced in terms of chemoheterotrophy, fermentation function, and conversion and utilization of nitrates and sulfates. This also explains the significant enhancement of the overall metabolic activity of the intestinal flora of mice after intervention with brown algae extract from the perspective of functional genes.

[0074] Low-dose (4 mg / mL) brown algae extract: significantly changed the α-diversity and β-diversity of the intestinal flora of mice; had a significant effect on the dominant bacterial genera Lactobacillus and Bifidobacterium at the species level; indicating that low-dose brown algae extract intake has a good effect on improving intestinal immunity.

[0075] Medium dose (12 mg / mL) of brown algae extract: significantly changed the β-diversity of the intestinal flora of mice, but had no significant effect on α-diversity; had a significant effect on the dominant bacterial genera Lactobacillus and Bifidobacterium at the species level; indicating that low-dose brown algae extract intake has a certain effect on improving intestinal immunity.

[0076] High-dose (36 mg / mL) brown algae extract: significantly changed the α-diversity and β-diversity of the intestinal flora of mice; made a more significant contribution to the changes in the dominant bacterial genera Lactobacillus and Bifidobacterium, and had a more significant impact on the two at the species level; indicating that high-dose brown algae extract intake has a better effect on improving intestinal immunity.

[0077] In summary, intervention with brown algae extracts in different dose groups can delay the decline of the thymus, an immune organ of mice, to varying degrees, improve the activity of immune cells, and promote the secretion of immune active factors, thus benefiting the body's immunity. It is worth noting that intervention with brown algae extracts in the low-dose and high-dose groups can effectively increase the abundance of beneficial intestinal bacteria, especially as an important prebiotic for the two beneficial bacteria, bifidobacteria and lactobacilli, thereby significantly improving the body's intestinal immunity. Among them, the effect of the high-dose group was more significant.

[0078] Although the present invention has been described in detail above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A brown algae extract for intestinal regulation, characterized in that: The brown algae extract is prepared by the following steps: 1) Bacterial fermentation: using one or more of Bacillus subtilis, Arthrobacter and Pseudoalteromonas elsdenii, activating and enriching the bacterial strains, inoculating them into a functional medium of alginate, controlling the temperature at 28° C. to 30° C., controlling the pH at 6.5 to 8.0, and fermenting the strains for 20 to 24 hours to obtain a bacterial fermentation liquid; 2) Preparation of alginate extract: Prepare a seaweed powder solution with a mass concentration of 8% to 12%, add the bacterial fermentation liquid obtained in step 1), and carry out biological reaction at 30° C. to 35° C. for 24 to 36 hours to obtain brown algae fermentation liquid.

2. The brown algae extract according to claim 1, characterized in that The brown algae extract is extracted from brown algae fermentation broth; the effective ingredients in the brown algae extract account for 45-68% by mass; the effective ingredients include oligosaccharides formed by sugar chains formed by guluronic acid (G) with a polymerization degree of 2-10, mannuronic acid (M) or a hybrid of the two connected by β-1,4 glycosidic bonds; the brown algae extract contains 25-32% by mass of brown algae polysaccharides.

3. The brown algae extract according to claim 1, characterized in that The bacterial species is a mixed bacterial species of Bacillus subtilis and Pseudoalteromonas elsdenii at a bacterial count ratio of 1:0.5-1.

4. The brown algae extract according to claim 1, characterized in that Step 1) The alginate functional medium contains the following components in mass proportion: seaweed powder 3-5 g / L, trypsin 3-5 g / L, glucose 10 g / L, K2 HPO4 5-8 g / L, chloramphenicol 2-10 μg / mL, magnesium sulfate 1-2 g / L, ferrous sulfate 0.1-0.2 g / L, and a pH value of 6.5-7.

0.

5. The brown algae extract according to claim 1, characterized in that In step 1), the temperature is controlled at 28° C. to 30° C., the pH is controlled at 6.5 to 7.0, and the strain is fermented and cultured for 20 to 24 hours.

6. The brown algae extract according to claim 1, characterized in that In step 2), the mass ratio of the seaweed powder solution to the bacterial fermentation liquid is 100:4-5.

7. The brown algae extract according to claim 1, characterized in that In step 2), the biological reaction is carried out at 30°C-35°C for 28 to 30 hours.

8. The brown algae extract according to any one of claims 1 to 7, characterized in that The method also includes step 3): removing insoluble polysaccharides by centrifugal filtration, obtaining oligosaccharides with a degree of polymerization of 2 to 6 by membrane filtration, and spray-drying the filtered solution at 80 to 100° C. to obtain brown algae extract.

9. Use of the brown algae extract according to any one of claims 1 to 8 in the preparation of intestinal regulating functional foods.

10. The use according to claim 9, characterized in that: The mass content of the brown algae extract in the intestinal tract regulating functional food is 0.4-3.6%.

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