Preparation method of banana resistant starch preparation for improving intestinal mucosal lesion

Abstract

The invention discloses a preparation method of a banana resistant starch preparation for improving intestinal mucosal lesion, and belongs to the technical field of resistant starch preparation. The preparation method comprises the following steps: (1) peeling and dicing green bananas, adding sterile water containing ascorbic acid, inoculating eurotium cristatum fermentation liquor, uniformly mixing, and fermenting to obtain a banana fermentation product; (2) centrifuging the banana fermentation product to remove supernate, and collecting precipitate; (3) resuspending the precipitate with sterile water, adding whey protein isolate, uniformly mixing, dropwise adding a sodium alginate solution, centrifuging, and collecting the precipitate; and (4) heating and cross-linking the precipitate, and then drying at low temperature to obtain the banana resistant starch. The banana resistant starch prepared by the preparation method disclosed by the invention can be used for remarkably improving intestinal mucosa injury and protecting intestinal mucosa.

Description

Technical Field

[0001] The invention relates to the technical field of resistant starch preparation, and in particular to a method for preparing a banana resistant starch preparation for improving intestinal mucosal damage. Background Art

[0002] Bananas (Musa acuminata) are one of the world's major fruit and food crops, boasting high yields, widespread distribution, nutritious, sweet, and soft flesh, and high nutritional value. Bananas also clear heat, moisten the intestines, detoxify, nourish yin and moisten dryness, promote fluid production and quench thirst, and are primarily used to treat fever, thirst, constipation, and hemorrhoidal bleeding, thus possessing medicinal value. However, bananas are difficult to store, especially ripe bananas, which are prone to spoilage and difficult to transport. Post-harvest storage and transportation are both expensive. my country's annual banana production is approximately 24 billion jin (approximately 1.5 billion kg), primarily sold fresh, with little further processing.

[0003] The development of the resistant starch industry undoubtedly presents a huge business opportunity for natural resistant starch sources such as green bananas, raw potatoes, and raw peas. Currently, the main methods for preparing resistant starch include hydrothermal treatment, debranching degradation, ultrasonication, microwave radiation, and steam heating. However, these methods all have certain drawbacks. For example, hydrothermal treatment, while simple, requires high temperatures, which can easily damage the structure of natural green banana resistant starch. Debranching degradation primarily involves enzymatically degrading starch branches using pullulanase to produce high-amylose resistant starch. Ultrasonication induces cavitation within starch granules during vibration, while microwave radiation can rearrange the starch structure, facilitating efficient binding between enzymes and substrates in enzyme-catalyzed reactions. Therefore, microwave radiation and ultrasonication are often used as auxiliary methods to pretreat starch before enzymatic or autoclaving methods are used to prepare resistant starch. However, these methods are generally used for scientific research and are rarely used in production. Therefore, there is an urgent need for a new method for preparing green banana resistant starch suitable for both scientific research and production, which would be of great significance to the development of the banana industry.

[0004] As an important part of the human digestive system, the intestinal mucosal barrier plays a key role in maintaining the stability of the body's internal environment, resisting the invasion of pathogens, and promoting the absorption of nutrients. In modern life, intestinal mucosal damage occurs more and more frequently, which is closely related to a variety of factors. From a dietary perspective, long-term high-fat, high-sugar diet patterns, as well as excessive intake of irritants such as alcohol, will change the microecological environment in the intestine, leading to an increase in harmful bacteria and a decrease in beneficial bacteria, which in turn triggers intestinal inflammatory reactions and destroys the integrity of the intestinal mucosa. In addition, drugs are also one of the important causes of intestinal mucosal damage. Non-steroidal anti-inflammatory drugs are widely used in clinical practice for anti-inflammatory, analgesic and antipyretic effects, but these drugs often cause adverse gastrointestinal reactions, among which intestinal mucosal damage is more common. In diseases such as ulcerative colitis and Crohn's disease, a large number of inflammatory cells infiltrate the intestinal mucosa, releasing various inflammatory mediators, such as tumor necrosis factor-α and interleukin-6. These inflammatory mediators not only directly damage intestinal epithelial cells and vascular endothelial cells, but also interfere with the repair process of the intestinal mucosa, leaving the intestinal mucosa in a state of continuous imbalance between damage and repair. Currently, intestinal mucosal damage is mostly repaired through medication, and there are no reports on the improvement of intestinal mucosal damage through the use of banana resistant starch. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a banana resistant starch preparation for improving intestinal mucosal damage, so as to solve the problems existing in the above-mentioned prior art. By optimizing the preparation process steps of banana resistant starch, the obtained banana resistant starch can significantly improve intestinal mucosal damage.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a method for preparing banana resistant starch, comprising the following steps:

[0008] (1) peeling and dicing a green banana, adding sterile water containing ascorbic acid, inoculating a fermentation liquid of Eurotium cristatum, mixing well, and fermenting to obtain a banana fermentation product;

[0009] (2) centrifuging the banana fermentation product to remove the supernatant and collect the precipitate;

[0010] (3) resuspending the precipitate with sterile water, adding whey protein isolate and mixing evenly, adding sodium alginate solution dropwise, centrifuging, and collecting the precipitate;

[0011] (4) heating the precipitate to cross-link it, and then drying it at low temperature to obtain banana resistant starch.

[0012] In the above scheme, after peeling and dicing the green bananas, sterile water containing ascorbic acid is added to prevent surface oxidation. Inoculating the bananas with Eurotium cristatum allows fermentation using pectin and starch as carbon sources, reducing pectin interference with the extraction of banana resistant starch and improving the extraction rate. Furthermore, fermentation with Eurotium cristatum mitigates the structural damage to resistant starch caused by traditional high-speed shearing of bananas into a pulp. Fermentation with Eurotium cristatum not only reduces interference from pectin and starch but also converts them into beneficial soluble monosaccharides, without disrupting the physical structure of resistant starch. Obtain precipitation by centrifugation, after resuspending, then add whey protein isolate, drip sodium alginate solution immediately afterwards, can avoid the precipitation of whey protein isolate like this, and can also make it and sodium alginate cross-linked to form fiber network structure, the resistant starch obtained is embedded, then can make outer layer whey protein isolate denaturation by 80 ℃ of short-term heating, increase the compactness of fiber network structure simultaneously, this temperature can not destroy the resistant starch embedded in it, thus in fact obtained a kind of novel improved resistant starch. This resistant starch is when digested, and the fiber network structure of outer layer is digested and degraded by stomach and small intestine, and when arriving at colon, resistant starch is released, has realized the effective controlled release of banana resistant starch. Therefore, for the banana modified starch prepared under specific conditions of the present invention, it is to fully bring into play its function in intestinal tract, and avoids the problem of poor effect caused by dissolving in other tissues simultaneously.

[0013] Optionally, the sterile water containing ascorbic acid is an aqueous solution containing 2.0‰-3.0‰ ascorbic acid, and the sterile water containing ascorbic acid is added to the green bananas in a volume 3-4 times the mass of the green bananas.

[0014] Optionally, the inoculation amount of the Eurotium cristatum fermentation liquid is 2%-4%, the fermentation temperature is 28-30°C, and the fermentation time is 20-40h. Under these conditions, the expanded culture can quickly obtain the Eurotium cristatum fermentation liquid, and the bacterial quality and bacterial concentration can meet the use requirements of the present invention.

[0015] Optionally, the fermentation broth of Eurotium cristatum is obtained by inoculating the Eurotium cristatum into a malt juice medium and expanding the culture. The bacterial concentration of the fermentation broth of Eurotium cristatum is 3.5×10 8 CFU / mL.

[0016] Optionally, the added amount of the whey protein isolate is 3.0%-4.0% of the total weight of the precipitate.

[0017] Optionally, the amount of the sodium alginate solution added is 1.0%-1.5% of the total weight of the precipitate, and the concentration of the sodium alginate solution is 2.0 g / L.

[0018] Cross-linking of whey protein isolate and sodium alginate solution within the above range can form a fibrous structure with the best encapsulation effect, which is beneficial to the efficient encapsulation of resistant starch.

[0019] Optionally, the precipitate is heated and cross-linked at 80°C for 1-5 minutes, and the low-temperature drying temperature is 30-45°C. Temperature has a certain impact on the denaturation of whey protein isolate and its cross-linking effect with sodium alginate. If the temperature is too low, it may lead to insufficient cross-linking and a loose structure, which is insufficient to ensure efficient embedding of resistant starch, thereby causing partial degradation of resistant starch. If the temperature is too high, it will affect the denaturation of the outer layer of whey protein isolate and destroy the structure of resistant starch, affecting its effectiveness after use.

[0020] The present invention also provides banana resistant starch prepared by the preparation method.

[0021] The invention also provides a composition containing the banana resistant starch.

[0022] The present invention also provides use of the banana resistant starch or the composition in preparing a medicine for improving intestinal mucosa.

[0023] The present invention discloses the following technical effects:

[0024] This invention extracts resistant starch from green bananas fermented with Eurotium cristatum, then encapsulates it with whey protein isolate and a sodium alginate cross-linked structure. The cross-linked structure is then further optimized to produce a modified banana resistant starch. Animal experiments have shown that the banana resistant starch produced by this invention significantly reduces inflammatory factors in the blood and intestinal tissue, increases the content of tight junction proteins in intestinal tissue, and significantly improves weight gain and stool formation. This suggests that the banana resistant starch produced by this invention can significantly improve intestinal mucosal damage and plays an important role in protecting the intestinal mucosa. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 is the relative expression level of tight junction protein ZO-1 mRNA;

[0027] Figure 2 is the relative expression level of tight junction protein occludin mRNA;

[0028] In the above figure, CK: blank control group; Sham: intestinal mucosal injury model group; S1: banana resistant starch experimental group (Example 1); S2: banana resistant starch experimental group (Example 2); S3: banana resistant starch experimental group (Example 3); D1: banana resistant starch experimental group (Comparative Example 1); D2: banana resistant starch experimental group (Comparative Example 2); D3: banana resistant starch experimental group (Comparative Example 3); D4: banana resistant starch experimental group (Comparative Example 4); *, indicates significance compared with CK, P﹤0.05; #, indicates significant difference compared with Sham, P﹤0.05. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0031] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0032] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] Resistant starch, also known as resistant starch or indigestible starch, cannot be enzymatically hydrolyzed in the small intestine, but can undergo fermentation reactions with volatile fatty acids in the human gastrointestinal colon.

[0035] Resistant starch is found in certain natural foods, such as potatoes, bananas, and rice. High-amylose corn starch, in particular, can contain up to 60% resistant starch. This starch is more difficult to degrade than other starches, digesting more slowly and absorbing and entering the bloodstream more slowly. Its properties are similar to those of soluble fiber, offering some slimming benefits, and it has recently become popular among those seeking beauty.

[0036] Numerous technical solutions for extracting resistant starch from green bananas have been disclosed in the prior art. For example, CN105852138B discloses a method for extracting natural resistant starch from bananas. This patent utilizes a combination of freezing and blanching for pretreatment, facilitating separation of the peel and pulp. Microbial fermentation is then combined with enzymatic treatment to remove other components and extract high-purity natural resistant starch from bananas. This method combines cold and hot treatments, microbial fermentation, enzymatic hydrolysis, and ultrasound. While this method can yield natural resistant starch from bananas, it is complex and requires strict control of multiple steps, such as ultrasound conditions. Another example is CN101427803B, which discloses pectin-modified resistant starch, a composition thereof, and a method for preparing resistant starch. This method is prepared by cross-linking starch with pectin via a pectinesterase reaction. This resistant starch has a low degree of amylase digestion and can therefore be used in foods, including nutritional supplements, to reduce calories and increase fiber content. This method primarily utilizes pectin to modify resistant starch, but this resistant starch introduces another dietary fiber, making it unclear whether the modified resistant starch will function as its original dietary fiber in the intestine. Therefore, given the diverse methods for extracting resistant starch in existing technologies, which vary in their ability to deliver the desired dietary fiber functions, exploring new methods for extracting resistant starch remains essential.

[0037] The Eurotium cristatum used in the embodiments of the present invention has a deposit number of CICC 2099 and can be purchased conventionally through the China Industrial Microbiological Culture Collection Administration Center. The present invention is not limited to this strain, and the public can purchase it through the above platform or other channels to obtain Eurotium cristatum with the same function.

[0038] Example 1 Preparation method of banana resistant starch

[0039] (1) Select bananas with green peels, peel them, and chop them into small pieces (e.g., 1×1×cm small pieces). Add 3 times the volume of sterile water containing ascorbic acid (2.5‰ ascorbic acid is added to prevent banana discoloration), inoculate with 2% Eurotium cristatum fermentation liquid, mix well, and ferment at 28°C for 20 h to obtain a banana fermentation product.

[0040] Among them, the cristatum was activated with malt extract agar medium, inoculated with malt extract culture medium and expanded at 30℃ for 3 days to obtain a bacterial count of ≥10 8 CFU / mL of fermentation broth; in this experiment, the bacterial concentration was adjusted to 3.5×10 8 CFU / mL of fermentation broth was inoculated;

[0041] (2) centrifuging the banana fermentation product to remove the supernatant and collect the precipitate;

[0042] (3) Resuspend the precipitate with sterile water, add 3.5% whey protein isolate by weight of the total precipitate and mix well, then add sodium alginate solution dropwise (the amount of sodium alginate is 1.0% of the total weight of the precipitate, the concentration is 2.0 g / L), centrifuge and collect the precipitate.

[0043] (4) The precipitate was treated at 80°C for 1 min, and then dried at 30°C to form granules, thereby obtaining banana resistant starch.

[0044] The banana natural resistant starch prepared in this example was observed under a polarizing microscope and a scanning electron microscope. It was found that the banana natural resistant starch had a distinct polarization cross, mostly in an X-shape, with the starch navel located at the center of the smaller end of the starch granule. The starch granule had an oval structure, with one end larger than the other.

[0045] Example 2 Preparation method of banana resistant starch

[0046] (1) Select bananas with green peels, peel them, and chop them into small pieces (e.g., 1×1×cm small pieces). Add 4 times the volume of sterile water containing ascorbic acid (2.0‰ ascorbic acid was added to prevent discoloration of the bananas), inoculate with 3% Eurotium cristatum fermentation liquid, mix well, and ferment at 29°C for 30 hours to obtain a banana fermentation product.

[0047] Among them, the cristatum was activated with malt extract agar medium, inoculated with malt extract culture medium and expanded at 30℃ for 3 days to obtain a bacterial count of ≥10 8 CFU / mL of fermentation broth; in this experiment, the bacterial concentration was adjusted to 3.5×10 8 CFU / mL of fermentation broth was inoculated;

[0048] (2) The banana fermentation product was centrifuged to remove the supernatant and collect the precipitate.

[0049] (3) Resuspend the precipitate with sterile water, add 4.0% whey protein isolate by weight of the total precipitate and mix well, then add sodium alginate solution dropwise (the amount of sodium alginate is 1.25% of the total weight of the precipitate, the concentration is 2.0 g / L), centrifuge, and collect the precipitate;

[0050] (4) The precipitate was treated at 80°C for 3 min, and then dried at 40°C to form granules, thereby obtaining banana resistant starch.

[0051] The banana resistant starch prepared in this example can be observed to have the same starch granule structure as that in Example 1.

[0052] Example 3 Preparation method of banana resistant starch

[0053] (1) Select bananas with green peels, peel them, and chop them into small pieces (e.g., 1×1×cm small pieces). Add 5 times the volume of sterile water containing ascorbic acid (2.5‰ ascorbic acid is added to prevent banana discoloration), inoculate with 4% Eurotium cristatum fermentation liquid, mix well, and ferment at 30°C for 40 hours to obtain a banana fermentation product.

[0054] Among them, the cristatum was activated with malt extract agar medium, inoculated with malt extract culture medium and expanded at 30℃ for 3 days to obtain a bacterial count of ≥10 8 CFU / mL of fermentation broth; in this experiment, the bacterial concentration was adjusted to 3.5×10 8 CFU / mL of fermentation broth was inoculated;

[0055] (2) centrifuging the banana fermentation product to remove the supernatant and collect the precipitate;

[0056] (3) resuspending the precipitate with sterile water, adding 3.0% whey protein isolate by weight of the total precipitate and mixing evenly, then adding sodium alginate solution dropwise (the amount of sodium alginate is 1.5% of the total weight of the precipitate, the concentration is 2.0 g / L), centrifuging, and collecting the precipitate;

[0057] (4) The precipitate was treated at 80°C for 5 min, and then dried at 45°C to form granules, thereby obtaining banana resistant starch.

[0058] The banana resistant starch prepared in this example can be observed to have the same starch granule structure as that in Example 1.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that: Eurotium cristatum is not inoculated, and pectinase is used instead for the enzymatic hydrolysis reaction. The details are as follows:

[0061] (1) Select bananas with green peels, peel them, and chop them into small pieces (e.g., 1×1×cm cubes). Add 3 times the volume of sterile water containing ascorbic acid (3.0‰ ascorbic acid was added to prevent discoloration of the bananas), and then add pectinase for enzymatic hydrolysis. The amount of pectinase added was 30 U / mL. The reaction conditions were: pH = 4.0, 55°C, and enzymatic hydrolysis time was 1 h to obtain a banana enzymatic hydrolyzate.

[0062] (2) The banana enzymatic hydrolysate was centrifuged to remove the supernatant, and the precipitate was collected and washed three times;

[0063] (3) The washed precipitate was resuspended in sterile water, 3.5% whey protein isolate was added and mixed evenly, and then sodium alginate solution (the amount of sodium alginate was 1.0% of the total weight of the precipitate, the concentration was 2.0 g / L) was added dropwise, and the precipitate was collected by centrifugation;

[0064] (4) The precipitate was treated at 80°C for 5 min and then dried at 45°C into granules to obtain banana resistant starch.

[0065] The banana resistant starch prepared in this comparative example can be observed to have the same typical starch granule structure as that in Example 1.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the addition method of whey protein isolate and sodium alginate is changed, as shown below:

[0068] (1) Same as (1) of Example 1;

[0069] (2) Same as (2) of Example 1;

[0070] (3) resuspending the precipitate with sterile water, adding 3.5% whey protein isolate and 1.0% sodium alginate by weight of the total precipitate, mixing evenly, centrifuging, and collecting the precipitate;

[0071] (4) Same as (4) of Example 1.

[0072] The banana resistant starch prepared in this comparative example can be observed to have the same typical starch granule structure as that in Example 1.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 1 is that the treatment temperature of the collected precipitate is changed, as shown below:

[0075] (1) Same as (1) of Example 1;

[0076] (2) Same as (2) of Example 1;

[0077] (3) Same as (3) of Example 1;

[0078] (4) The precipitate was treated at 90°C for 1 min, and then dried at 30°C into granules to obtain banana resistant starch.

[0079] The banana resistant starch prepared in this comparative example can be observed to have the same typical starch granule structure as that in Example 1.

[0080] Comparative Example 4

[0081] The difference between this comparative example and Example 1 is that the treatment temperature of the collected precipitate is changed, as shown below:

[0082] (1) Same as (1) of Example 1;

[0083] (2) Same as (2) of Example 1;

[0084] (3) Same as (3) of Example 1;

[0085] (4) The precipitate was treated at 50°C for 1 min and then dried at 30°C into granules to obtain banana resistant starch.

[0086] The banana resistant starch prepared in this comparative example can be observed to have the same typical starch granule structure as that in Example 1.

[0087] Animal experiments

[0088] The banana resistant starch prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was used to conduct an intestinal mucosal injury mouse model experiment.

[0089] Male Balb / c mice of the same age, weighing 20±1g, were selected and randomly divided into 9 groups after one week of acclimatization:

[0090] (1) Blank control group;

[0091] (2) Banana resistant starch experimental group (Examples 1-3);

[0092] (3) banana resistant starch control group (Comparative Examples 1-4);

[0093] (4) Intestinal mucosal injury model group.

[0094] Eight mice were included in each group. The blank control group was gavaged with sterile distilled water, while the other groups were gavaged with sterile distilled water containing 8% DSS. The model was established after 8 days. The banana resistant starch experimental group and the banana resistant starch control group were gavaged with the corresponding resistant starch solution once a day at a dose of 100 μg / kg / d. The intestinal mucosal injury model group and the blank control group were gavaged with an equal amount of normal saline daily for one week. After the last dose, the mice were fasted for 24 hours, weighed, and the stool characteristics were observed. After the experiment, blood was collected from the medial canthus vein, and serum was obtained to detect the levels of proinflammatory cytokines IL-1β and TNF-α in the blood. Afterwards, the mice were anesthetized and killed, and small intestinal tissue was obtained to detect the levels of inflammatory factors IL-1β and TNF-α in the small intestinal tissue, as well as the relative expression levels of tight junction proteins ZO-1 and occludin mRNA.

[0095] Table 1 Mouse body weight and fecal characteristics

[0096] Grouping Weight gain rate (%) Stool characteristics Blank control group 115.0 normal Intestinal mucosal injury model group 21.9 Diarrhea, bloody stools Banana resistant starch experimental group (Example 1) 97.0 normal Banana resistant starch experimental group (Example 2) 93.0 normal Banana resistant starch experimental group (Example 3) 93.5 normal Banana resistant starch control group (Comparative Example 1) 52.5 normal Banana resistant starch control group (Comparative Example 2) 59.7 normal Banana resistant starch control group (Comparative Example 3) 66.5 normal Banana resistant starch control group (Comparative Example 4) 64.3 normal

[0097] Note: Weight gain rate (%) = (final weight - initial weight) / initial weight × 100

[0098] The results in Table 1 show that compared with the intestinal mucosal injury model group, the banana resistant starch of Examples 1-3 and Comparative Examples 1-4 can significantly improve diarrhea and bloody stools in mice after oral gavage, and weight gain is also significantly improved. In addition, the improvement effect of the banana resistant starch of Examples 1-4 is more obvious than that of the banana resistant starch of Comparative Examples 1-4.

[0099] Table 2 Proinflammatory factor levels in blood

[0100]

[0101]

[0102] The results in Table 2 show that compared with the intestinal mucosal injury model group, the banana resistant starch of Examples 1-3 and Comparative Examples 1-4 can significantly reduce the levels of pro-inflammatory factors IL-1β and TNF-α in the blood after oral gavage, and the banana resistant starch of Examples 1-4 has a more obvious effect than the banana resistant starch of Comparative Examples 1-4.

[0103] Table 3 Expression levels of inflammatory factors in intestinal tissue

[0104]

[0105] The results in Table 3 show that compared with the intestinal mucosal injury model group, the banana resistant starch of Examples 1-3 and Comparative Examples 1-4 can significantly reduce the levels of proinflammatory factors IL-1β and TNF-α in intestinal tissue after oral gavage, and the banana resistant starch of Examples 1-4 has a more obvious effect than the banana resistant starch of Comparative Examples 1-4.

[0106] like Figure 1 and Figure 2 As shown in the results, compared with the intestinal mucosal injury model group, the banana resistant starch of Examples 1-3 and Comparative Examples 1-4 can significantly increase the relative expression levels of intestinal tight junction ZO-1 and Occludin mRNA after oral gavage (P < 0.05), and the effect of the banana resistant starch of Examples 1-4 is more obvious than that of the banana resistant starch of Comparative Examples 1-4.

[0107] These experimental results demonstrate that the banana resistant starch prepared in this invention significantly reduces the levels of inflammatory factors in the blood and intestines, significantly improving intestinal inflammation. It also increases the relative expression of ZO-1 and occludin mRNA, enhancing tight junctions between cells, thereby restoring the integrity and permeability of the intestinal barrier and preventing molecules from entering the bloodstream. These adjustments to intestinal tissue significantly improve the appearance, weight, and stool formation of mice. This demonstrates that the banana resistant starch prepared in this invention can alleviate intestinal mucosal damage and plays an important role in protecting the intestinal mucosa.

[0108] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing banana resistant starch, characterized in that: The following steps are involved: (1) peeling and dicing a green banana, adding sterile water containing ascorbic acid, inoculating a fermentation liquid of Eurotium cristatum, mixing well, and fermenting to obtain a banana fermentation product; (2) centrifuging the banana fermentation product to remove the supernatant and collect the precipitate; (3) resuspending the precipitate with sterile water, adding whey protein isolate and mixing evenly, adding sodium alginate solution dropwise, centrifuging, and collecting the precipitate; (4) heating the precipitate to cross-link it, and then drying it at low temperature to obtain banana resistant starch.

2. The preparation method according to claim 1, wherein The sterile water with ascorbic acid content is an aqueous solution of 2.0‰-3.0‰ ascorbic acid, and the sterile water with ascorbic acid content is added to the green bananas in a volume 3-4 times the mass of the green bananas.

3. The preparation method according to claim 1, wherein The inoculation amount of the Eurotium cristatum fermentation liquid is 2%-4%, the fermentation temperature is 28-30° C., and the fermentation time is 20-40 hours.

4. The preparation method according to claim 1, wherein The fermentation liquid of Eurotium cristatum is obtained by inoculating the Eurotium cristatum into a malt juice medium and expanding the culture. The bacterial concentration of the fermentation liquid of Eurotium cristatum is 3.5×10 8 CFU / mL.

5. The preparation method according to claim 1, wherein The added amount of the whey protein isolate is 3.0%-4.0% of the total weight of the precipitate.

6. The preparation method according to claim 1, wherein The amount of the sodium alginate solution added is 1.0%-1.5% of the total weight of the precipitate, and the concentration of the sodium alginate solution is 2.0 g / L.

7. The preparation method according to claim 1, wherein The conditions for heating and cross-linking the precipitate are: treating at 80°C for 1-5 minutes; and the temperature for low-temperature drying is: 30-45°C.

8. Banana resistant starch obtained by the preparation method according to any one of claims 1 to 7.

9. A composition, characterized in that Contains the banana resistant starch according to claim 8.

10. Use of the banana resistant starch according to claim 8 or the composition according to claim 9 in preparing a medicament for improving intestinal mucosal damage.

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