Modified buckwheat bran powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of food processing, and particularly relates to modified buckwheat bran powder as well as a preparation method and application thereof. According to the preparation method disclosed by the invention, through mutual cooperation of wet-process superfine grinding and high-humidity extrusion processes, the proportion of soluble dietary fibers, the solubility, the expansibility, the oil holding capacity and the cholesterol adsorption capacity of the buckwheat bran are improved, and the particle size and the proportion of a triple-helix three-dimensional structure of the buckwheat bran powder as well as the proportion of cellulose, hemicellulose and lignin in insoluble dietary fibers are reduced. The research on a low-concentration alcohol-induced mouse gastric mucosa injury model shows that the modified buckwheat bran powder can repair gastric mucosa tissue injury, inhibit release of gastric mucosa cell inflammatory factors and protect the barrier integrity of gastric mucosa epithelial cells, and the content of butyric acid in gastric metabolites is remarkably increased; the microbial abundance and total amount of gastric flora are remarkably increased, and the microbial abundance of butyric acid producing bacteria such as actinomycetes is remarkably increased.

Description

Technical Field

[0001] The present application belongs to the technical field of food processing, and specifically relates to a modified buckwheat bran powder and a preparation method and application thereof. Background Art

[0002] Insoluble dietary fiber refers to the fiber components that cannot be broken down by digestive enzymes in the human digestive system, which mainly include cellulose, hemicellulose and lignin. This type of fiber mainly comes from plant cell walls and is commonly found in whole grains, vegetables and fruit skins. They can promote intestinal peristalsis and help prevent constipation. In addition, insoluble dietary fiber can also help maintain the balance of intestinal flora, playing an important role in maintaining the health of the human digestive system.

[0003] However, since insoluble dietary fibers are not easily broken down by digestive enzymes, they mainly affect the digestion process through physical effects. Although this has an important positive effect on digestion, excessive intake or large particles of insoluble dietary fiber may cause physical friction and irritation to the gastric mucosa. For people who already have gastritis, gastric ulcers or other stomach diseases, this physical stimulation may aggravate the condition, leading to increased discomfort, increased stomach pain, acid reflux and other symptoms. Therefore, for these people, the intake of insoluble dietary fiber should be carefully controlled, and milder food sources should be selected.

[0004] Buckwheat is a dicotyledonous plant belonging to the genus Fagopyrum of the Polygonaceae family. The bran on the outer layer of its seeds is rich in dietary fiber, which makes buckwheat bran a very valuable food source. It not only provides rich dietary fiber, but also contains a variety of other nutrients, such as vitamins (B vitamins, vitamin E), minerals (magnesium, zinc, iron, copper, etc.) and antioxidants. These ingredients work together to help maintain cardiovascular health, control blood sugar levels, lower cholesterol, and provide anti-inflammatory and antioxidant protection. However, insoluble dietary fiber accounts for more than 80% of buckwheat bran, which has a heavy consumption burden for people with sensitive stomachs or existing gastrointestinal problems, which directly limits its widespread application and acceptance among special populations. Summary of the invention

[0005] In order to solve the above technical problems, the present application mainly provides a modified buckwheat bran powder that can improve the gastric mucosal barrier function, which is specifically achieved through the following technical solutions:

[0006] In a first aspect, the present application provides a method for preparing a modified buckwheat bran powder, comprising the following steps: S1, wet ultrafine grinding of buckwheat bran powder pretreated with alkali solution to obtain ultrafine grinding powder; S2, twin-screw extrusion treatment of the ultrafine grinding powder with a moisture content of 65-85% at an extrusion treatment temperature of 70-120°C to obtain modified buckwheat bran powder.

[0007] Preferably, in step S1, during the alkali solution pretreatment, the mass volume ratio of buckwheat bran powder to alkali solution is 1:(5-10).

[0008] Preferably, in step S1, the alkali solution is 0.01-0.03M sodium hydroxide.

[0009] Preferably, in step S1, the mass volume ratio between buckwheat bran powder and alkali solution during the wet ultrafine grinding process is 1:(2-4).

[0010] Preferably, in step S2, during the extrusion process, a temperature gradient setting of first increasing the temperature and then decreasing the temperature is formed.

[0011] Preferably, in step S2, the extrusion processing parameters also include: a feed rate of 6 to 8 kg / h, and a screw speed of 50 to 100 rpm / min.

[0012] In a second aspect, the present application provides a modified buckwheat bran powder prepared by any of the above-mentioned preparation methods.

[0013] In a third aspect, the present application proposes the use of the above-mentioned modified buckwheat bran powder in gastric mucosal repair drugs.

[0014] Compared with the prior art, this application has the following beneficial effects:

[0015] This application improves the soluble dietary fiber ratio, solubility, swelling, oil holding capacity, and cholesterol adsorption capacity of buckwheat bran through the mutual cooperation of wet ultrafine grinding and high-humidity extrusion process, and reduces the particle size of buckwheat bran powder, the ratio of triple helical structure, and the ratio of cellulose, hemicellulose, and lignin in insoluble dietary fiber. Using a low-concentration alcohol-induced gastric mucosal injury model in mice, it was found that the modified buckwheat bran powder can repair gastric mucosal tissue damage, inhibit the release of inflammatory factors in gastric mucosal cells, and protect the integrity of the gastric mucosal epithelial cell barrier. The butyric acid content in gastric metabolites is significantly increased, the abundance and total amount of gastric flora microorganisms are significantly increased, and the abundance of butyric acid-producing microorganisms such as actinomycetes is significantly increased. Compared with the simple use of wet ultrafine grinding, or high-humidity extrusion process, it has unexpected technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to clearly introduce the embodiments, the drawings of the accompanying drawings are briefly introduced below:

[0017] Figure 1 This is a diagram showing the gastric mucosal damage in each group in performance test 2. DETAILED DESCRIPTION

[0018] The present application will be further described below in the form of specific embodiments. Those of ordinary skill in the art will be able to implement the present application based on these descriptions. In addition, the embodiments of the present application involved in the following description are generally only embodiments of a part of the present application, rather than all embodiments. Therefore, based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present application.

[0019] Example 1

[0020] This embodiment discloses a method for preparing modified buckwheat bran powder, which specifically comprises the following steps:

[0021] S1. Wet ultrafine grinding: Buckwheat bran powder with an insoluble dietary fiber ratio of 85% is used as raw material. First, 0.02M NaOH solution is used with a solid-liquid ratio of 1:5 (W / V) to soak it at room temperature for 12 hours. Then, the buckwheat bran powder is processed using a colloid mill under wet conditions, wherein the grinding tooth gap is 10 μm, the solid-liquid ratio is 1:4 (W / V), and the grinding time is 15 minutes. Ultrafine buckwheat bran powder with a D90 of 12 μm can be obtained.

[0022] S2, high humidity extrusion: After being pre-treated by ultrafine grinding, the buckwheat bran powder was treated by twin-screw extrusion under high humidity conditions, wherein the barrel temperature gradient heating program was 70, 80, 90, 90, 100, 100, 80, 70°C, the screw speed was 70rpm / min, the physical water content was 80%, and the feed rate was 6kg / h. After the extrudate was dried by hot air at 60°C for 12h, the modified buckwheat bran powder was obtained.

[0023] Example 2

[0024] This embodiment discloses a method for preparing modified buckwheat bran, which specifically comprises the following steps:

[0025] S1. Wet ultrafine grinding: Buckwheat bran powder with an insoluble dietary fiber ratio of 85% is used as raw material. First, 0.02M NaOH solution is used with a solid-liquid ratio of 1:10 (W / V) to soak it at room temperature for 8 hours. Then, the buckwheat bran powder is processed using a colloid mill under wet conditions, wherein the grinding tooth gap is 5μm, the solid-liquid ratio is 1:3 (W / V), and the grinding time is 10min. Ultrafine buckwheat bran powder with a D90 of 20μm can be obtained.

[0026] S2, high humidity extrusion: After being pre-treated by ultrafine grinding, the buckwheat bran powder was treated by twin-screw extrusion under high humidity conditions, wherein the barrel temperature gradient heating program was 80, 90, 100, 110, 120, 100, 90, 70°C, the screw speed was 80rpm / min, the physical water content was 70%, and the feed rate was 4kg / h. After the extrudate was dried by hot air at 60°C for 12h, the modified buckwheat bran powder was obtained.

[0027] Example 3

[0028] This embodiment discloses a method for preparing modified buckwheat bran, which specifically comprises the following steps:

[0029] S1. Wet ultrafine grinding: Buckwheat bran powder with an insoluble dietary fiber ratio of 85% is used as raw material. First, 0.03M NaOH solution is used with a solid-liquid ratio of 1:10 (W / V) to soak it at room temperature for 8 hours. Then, the buckwheat bran powder is processed using a colloid mill under wet conditions, wherein the grinding tooth gap is 5 μm, the solid-liquid ratio is 1:2 (W / V), and the grinding time is 10 min. Ultrafine buckwheat bran powder with a D90 of 20 μm can be obtained.

[0030] S2, high humidity extrusion: After being pre-treated by ultrafine grinding, the buckwheat bran powder was treated by twin-screw extrusion under high humidity conditions, wherein the barrel temperature gradient heating program was 80, 90, 100, 110, 120, 100, 90, 70°C, the screw speed was 50rpm / min, the physical water content was 65%, and the feed rate was 6kg / h. After the extrudate was dried by hot air at 60°C for 12h, the modified buckwheat bran powder was obtained.

[0031] Example 4

[0032] This embodiment discloses a method for preparing modified buckwheat bran, which specifically comprises the following steps:

[0033] S1. Wet ultrafine grinding: Buckwheat bran powder with an insoluble dietary fiber ratio of 85% is used as raw material. First, 0.02M NaOH solution is used with a solid-liquid ratio of 1:10 (W / V) to soak it at room temperature for 8 hours. Then, the buckwheat bran powder is processed using a colloid mill under wet conditions, wherein the grinding tooth gap is 5μm, the solid-liquid ratio is 1:3 (W / V), and the grinding time is 10min. Ultrafine buckwheat bran powder with a D90 of 20μm can be obtained.

[0034] S2, high humidity extrusion: After being pre-treated by ultrafine grinding, the buckwheat bran powder was treated by twin-screw extrusion under high humidity conditions, wherein the barrel temperature gradient heating program was 80, 90, 100, 110, 120, 100, 90, 70°C, the screw speed was 50rpm / min, the physical water content was 85%, and the feed rate was 8kg / h. After the extrudate was dried by hot air at 60°C for 12h, the modified buckwheat bran powder was obtained.

[0035] Comparative Example 1

[0036] The difference between the preparation method of buckwheat bran powder in this comparative example and that in Example 1 is that step S2 is not included.

[0037] Comparative Example 2

[0038] The difference between the preparation method of buckwheat bran powder in this comparative example and that in Example 1 is that step S1 is not included. Buckwheat bran powder with an insoluble dietary fiber ratio of 85% is used as a raw material, the moisture content of the material is adjusted to 80%, and then the buckwheat bran powder is processed by twin-screw extrusion.

[0039] Performance Test 1

[0040] This performance test is carried out on the buckwheat bran powder of the embodiment, comparative example and blank control group. The test objects and methods are as follows: SDF, IDF and TDF content: measured by Megazyme kit. Insoluble dietary fiber composition: measured by lignin, cellulose and hemicellulose kit (Jiangsu Edison Biotechnology Co., Ltd., Jiangsu, China). Particle size determination: the sample is dissolved in pure water and measured by laser particle size analyzer when the transmittance is 0.10-0.15, and the result is expressed as D90. Solubility determination: weigh 2.00g (record m) of buckwheat bran powder in a beaker, add 50mL of distilled water (record V), stir with a magnetic stirrer for 30min, then filter with filter paper, collect the filtrate; evaporate the filtrate in a boiling water bath, and record the mass m of the soluble matter. Solubility = m / V×1000. Water holding capacity determination: 1g sample is mixed with 40mL of water, placed for 24h, centrifuged at 4000rpm for 15min, remove excess water, and weigh and calculate. Swelling test: Take 0.3g sample and mix with 5mL water, add to the volumetric flask. After the sample is soaked and swelled at room temperature for 5h, the final volume of the swollen fiber is recorded. Viscosity test: Weigh 0.3g sample and mix thoroughly with 25g water, and use a viscometer to measure the sample viscosity. The integrated table is as follows:

[0041] Table 1. Physical and chemical test results

[0042]

[0043]

[0044] Please refer to the total content of soluble dietary fiber and insoluble dietary fiber in each group in the above table. It can be found that the present application greatly reduces the content of insoluble dietary fiber in buckwheat bran powder and increases the content of soluble dietary fiber through the cooperation of wet superfine grinding and high-humidity extrusion process, which has unexpected technical effects. Specifically, the content of soluble dietary fiber (SDF) in the modified buckwheat bran powder prepared in this embodiment 1 is about 2.13 times that of the blank group, and the content of insoluble dietary fiber (IDF) is about 46.89% of the blank group. However, the content of soluble dietary fiber in the modified buckwheat bran powder prepared in Comparative Example 1 (simply using the wet ultrafine grinding process in Example 1) is only 1.61 times that of the blank group, and the insoluble dietary fiber is about 69.57% of the blank group; the content of soluble dietary fiber in the modified buckwheat bran powder prepared in Comparative Example 2 (simply using the high-humidity extrusion process in Example 1) is only 1.75 times that of the blank group, and the insoluble dietary fiber is about 62.65% of the blank group. It can be seen that the regulating effect of dietary fiber in the comparative example is far less than that of the present application. In addition, it is particularly important to point out that the content of soluble dietary fiber in the modified buckwheat bran powder prepared in Example 2 of the present application is about 2.37 times that of the blank group, and the insoluble dietary fiber (IDF) is about 35.42% of the blank group, which greatly reduces the content of insoluble dietary fiber and has unexpected technical effects.

[0045] Please refer to the particle size of each group in the above table. It can be found that the present application greatly reduces the particle size of the modified buckwheat bran powder by cooperating with the wet ultrafine grinding and high-humidity extrusion process. The particle size of the modified buckwheat bran powder D90 prepared in Example 1 is about 30.15% of that of the blank control group. However, the particle size of the modified buckwheat bran powder D90 prepared in Comparative Example 1 (simply using the wet ultrafine grinding process in Example 1) is about 50.45% of that of the blank control group. The particle size of the modified buckwheat bran powder D90 prepared in Comparative Example 2 (simply using the high-humidity extrusion process in Example 1) is about 75.1% of that of the blank control group, and its effect is far less than that of the present application. In addition, it should be particularly pointed out that the particle size of the modified buckwheat bran powder D90 prepared in Example 2 of the present application is about 17.05% of that of the blank control group, which has unexpected technical effects.

[0046] In addition, by comparing the relevant parameters of Example 1, Comparative Example 1, Comparative Example 2 and the blank control group, it can be found that in addition to the distribution of dietary fiber content and particle size, the process of wet ultrafine grinding and high-humidity extrusion process will have an impact on other physical and chemical parameters of modified buckwheat bran powder, such as solubility, water holding capacity, swelling power and viscosity, and the adjustment of these physical and chemical factors has a more comprehensive effect on modified buckwheat bran powder in gastric mucosal repair.

[0047] Performance Test 2

[0048] This performance test tests the improvement effect of the gastric mucosal barrier function of the buckwheat bran powder of the embodiment and the comparative example. Specifically, 8-week-old male ICR mice were selected and randomly divided into an untreated group, an alcoholic gastric mucosal injury model group, an embodiment 1 group, an embodiment 2 group, a comparative example 1 group and a comparative example 2 group after 7 days of adaptation. The untreated group of mice was gavaged with the same volume of normal saline; the alcoholic gastric mucosal injury model group, the embodiment 1 group, the embodiment 2 group, the comparative example 1 group and the comparative example 2 group of mice were gavaged with 30% (v / v) ethanol at a dose of 1 mL / kg·bw daily for 4 weeks to establish a chronic AGMI model; during the period, from the third week, the embodiment 1 group, the embodiment 2 group, the comparative example 1 group and the comparative example 2 group of mice daily ingested the buckwheat bran powder sample solution disclosed in the embodiment 1 group, the embodiment 2 group, the comparative example 1 group and the comparative example 2 group, at a dose of 400 mg / kg·bw, for 2 weeks. Fresh feces of mice in different groups were collected 3 days before the end of the experiment and frozen for later use. At the end of the experiment, the mice were fasted for 12 h in advance, blood was collected from their eyeballs and they were killed by cervical dislocation. The plasma, gastric tissue, gastric contents and colon tissue of each group of mice were immediately collected.

[0049] 1. Determination of gastric protective factor and inflammatory factor levels

[0050] The levels of gastric protective factors and inflammatory factors were measured using ELISA kits, and the results are as follows:

[0051] Table 2. Levels of gastric protective factors and inflammatory factors

[0052]

[0053] By observing the levels of nitric oxide, epidermal growth factor and tumor necrosis factor α in each group in the above table, it can be found that at an intake dose of 400 mg / kg·bw, the gastric protection factor level and inflammatory factor level of mice that ingested the modified buckwheat bran powder prepared by the present application for two weeks were greatly reduced. However, the gastric protection factor level and inflammatory factor level of mice that ingested the modified buckwheat bran powder prepared by comparative examples 1 and 2 for two weeks were still poor compared with those of Example 1.

[0054] 2. Observation of gastric mucosal barrier

[0055] The gastric tissues of mice in the model group, the untreated group, the example 1 group, the example 2 group, the comparative example 1 group and the comparative example 2 group were fixed with 4% paraformaldehyde solution, and then sliced ​​and stained with H&E to observe the gastric mucosal damage. Referring to the attached figure, it can be found that the gastric mucosal surface of the model group is atrophic, while the other groups have significantly improved this histopathological state, and the thickness of the gastric mucosa and the stability of the gastric structure have been improved.

[0056] 3. Analysis of short-chain fatty acid content in the stomach

[0057] This performance test is performed on the buckwheat bran powder of the untreated group, the embodiment and the comparative group for in vitro fermentation of short-chain fatty acids. The method for in vitro fermentation of short-chain fatty acids is as follows: 0.5g of gastric contents are added to 5mL of PBS buffer, and vortexed to obtain a 10% (w / v) content dilution. 0.5mL of the dilution is added to 100μL of crotonic acid-metaphosphoric acid solution, vortexed for 2min, centrifuged at 10000r / min for 5min at 4°C, and the supernatant is filtered through a 0.45μm aqueous filter membrane. A highly polar DB-FFAP column (0.32mm×30m×0.5μm, Agilent) is used to detect SCFAs in the intestinal content dilution with crotonic acid as the internal standard. The injection port parameters are as follows: temperature 250℃, carrier gas type N2, injection volume 1μL, purge flow 3.0mL, injection mode is split mode (split ratio 5:1), total flow 12.1mL / min, chromatographic column flow 2.3mL / min. Column box parameters: starting temperature 75℃, heating rate (increase to 180℃ at 20℃ / min and hold for 1min, increase to 220℃ at 40℃ / min and hold for 1min, the program time is 8.05min in total). Flame ionization detector parameters: temperature is 250℃, tail gas and flow are N2 / H2 / air, 30 / 40 / 400mL / min. The following table is summarized:

[0058] Table 3. Results of in vitro fermentation of short-chain fatty acids

[0059]

[0060] In a mouse model with impaired gastric mucosal barrier function, after ingesting modified buckwheat bran powder, the short-chain fatty acids (such as acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric acid) and total acid levels in the mouse stomach were significantly higher than those in the group treated with normal saline alone. These short-chain fatty acids, especially acetic acid, propionic acid and butyric acid, as prebiotics, promote the growth of beneficial bacteria (such as bifidobacteria and lactic acid bacteria), inhibit the reproduction of harmful bacteria, and maintain or restore the balance of gastrointestinal flora. The repair of gastric mucosal barrier function can be indirectly affected, and the above-mentioned short-chain fatty acid content and proportion distribution are directly related to the wet superfine grinding and high-humidity extrusion process of the present application. In addition, short-chain fatty acids, especially butyric acid, have anti-inflammatory properties and can reduce inflammatory reactions by regulating the function of immune cells, which may be conducive to the repair of gastric mucosal barrier. Example 1 The content of butyric acid or isobutyric acid in the modified buckwheat bran powder prepared by wet superfine grinding and high-humidity extrusion process exceeds that of Comparative Example 1 and Comparative Example 2.

[0061] 4. Analysis of bacterial flora composition

[0062] The DNA in the culture medium was extracted using a kit, and the bacterial 16SrDNA gene in the V3-V4 region was amplified by PCR after designing and synthesizing primer adapters. The purified product was detected by agarose gel electrophoresis. After fluorescence quantification and library preparation, the sequencing adapter and amplification product were combined on the Illumina HiSeq 2500 platform, tested on the machine, and the data were analyzed for corresponding bioinformatics. The following table is obtained:

[0063] Table 4. Analysis of bacterial flora composition

[0064]

[0065]

[0066] It can be found from the above table that the ratio of bifidobacteria to Escherichia coli (B / E) in the gastric flora of the model group is low, indicating that the flora in the gastric tissue is dysbiotic, and the abundance of bifidobacteria in the sample groups is significantly increased, and the B / E value is significantly increased, showing the positive regulatory effect of the modified buckwheat bran powder on the gastrointestinal flora. In particular, the increase in bifidobacteria in the Example 1 group and the Example 2 group is more obvious, and the increase in the B / E value is particularly significant, which further confirms the effectiveness of the modified buckwheat bran powder prepared by the two preparation processes in improving gastric mucosal damage.

Claims

1. A method for preparing modified buckwheat bran powder, characterized in that: The following steps are involved: S1, performing wet ultrafine grinding on the buckwheat bran powder pretreated with alkali solution to obtain ultrafine grinding powder; S2. The ultrafine powder with a moisture content of 65-85% is subjected to twin-screw extrusion treatment at a temperature of 70-120° C. to obtain modified buckwheat bran powder.

2. The method for preparing modified buckwheat bran powder according to claim 1, characterized in that: In step S1, during the alkali solution pretreatment, the mass volume ratio between the buckwheat bran powder and the alkali solution is 1: (5-10).

3. The method for preparing modified buckwheat bran powder according to claim 2, characterized in that: In step S1, the alkali solution is 0.01-0.03M sodium hydroxide.

4. The method for preparing modified buckwheat bran powder according to claim 1, characterized in that: In step S1, the mass volume ratio between buckwheat bran powder and alkali solution during the wet ultrafine grinding process is 1: (2-4).

5. The method for preparing modified buckwheat bran powder according to claim 1, characterized in that: In step S2, during the extrusion process, a temperature gradient setting of first increasing the temperature and then decreasing the temperature is formed.

6. The method for preparing modified buckwheat bran powder according to claim 1, characterized in that: In step S2, the extrusion processing parameters also include: a feed rate of 6 to 8 kg / h, and a screw speed of 50 to 100 rpm / min.

7. A modified buckwheat bran powder, characterized in that: The preparation method is described in any one of claims 1 to 6.

8. Use of the modified buckwheat bran powder according to claim 7 in a gastric mucosal repairing drug.

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