Banana resistant starch, preparation method thereof and application of banana resistant starch in preparation of health food

Abstract

The invention discloses banana resistant starch as well as a preparation method and application thereof in preparation of health-care food, and relates to the technical field of biology. The preparation method comprises the following steps: peeling immature bananas, performing irradiation disinfection, adding sterile water, performing grinding and pulping, and performing sieving with a 60-mesh sieve so as to obtain slurry; inoculating lactobacillus brevis and kluffa yeast into the slurry, and performing fermentation treatment to obtain fermentation liquor; standing the fermentation liquor, removing the supernatant, cleaning the precipitate with sterile water, and drying to obtain the banana resistant starch. The banana resistant starch prepared by performing combined fermentation treatment on lactobacillus brevis and Kluffa yeast can remarkably enhance the blood glucose metabolism regulation capability under the influence of high fat, so that the banana resistant starch can be applied to preparation of health-care food beneficial to maintaining the blood glucose health level. The method has important practical application prospects and is particularly suitable for market application and popularization.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to banana resistant starch, a preparation method thereof and application thereof in the preparation of health food. Background Art

[0002] Resistant starch is a porous white powder with no odor and low water holding capacity. There is no precise chemical classification yet. Currently, resistant starch is mostly divided into five types based on the source of starch and its anti-enzymatic mechanism:

[0003] (1) RS1 physically trapped starch

[0004] RS1 resistant starch refers to starch that is inaccessible to amylase. It is mainly formed because the starch is embedded in the food matrix and is difficult to contact with enzymes due to the barrier effect of the cell wall or the isolation effect of protein, so it is not easy to digest. It mainly exists in whole or partially ground grains and beans. Physical actions such as crushing and grinding during processing and chewing during eating can destroy starch particles and convert them into digestible starch.

[0005] (2) RS2 resistant starch granules

[0006] RS2 refers to raw starch granules that have not been gelatinized and immature starch granules. This type of starch has a special conformation or crystal structure and is highly resistant to enzymes. It is often found in raw potatoes, raw peas, and green bananas.

[0007] (3) RS3 retrograded starch

[0008] RS3 refers to the partial recrystallization of gelatinized starch during cooling or storage. Due to the appearance of the crystallization area, the glucosidic bonds of amylase are prevented from approaching the crystallization area, and the binding sites in the active groups of amylase are prevented from binding to the starch molecules, resulting in the inability to be completely acted upon by amylase and resistance to enzymolysis. The resistant starch formed by the aging of amylose is difficult to be acted upon by enzymes, while the aging of amylopectin has less resistance to digestion and can be reversed after heating. It is often found in cold rice, cold bread, and fried potato chips.

[0009] (4) RS4 chemically modified starch

[0010] RS4 refers to a type of resistant starch that is resistant to enzymes due to changes in the structure of starch molecules caused by genetic or chemical modification, such as cross-linked starch, grafted copolymer starch with a high grafting frequency, etc. Resistant starch is similar to dietary fiber in physiological function, but has a greater effect. The reason may be that in the colon, RS fermentation produces more short-chain fatty acids than DF, which reduces the intestinal pH more significantly.

[0011] (5) RS5 Amylose-lipid complexed starch

[0012] RS5 is a polymer formed by the long-chain part of amylopectin or straight-chain starch in starch combined with lipids. The resistance of this type of starch to enzymatic hydrolysis is mainly due to the presence of lipids in the major and minor grooves of the double helix, which changes the structure of starch from a planar helix to a three-dimensional helix, and this structure is difficult to bind to amylase. At present, there is no unified definition of RS5 at home and abroad. Some researchers define RS5 as resistant maltodextrin, and the starch molecules are rearranged purposefully during the processing process to make maltodextrin water-soluble and digestive enzyme-resistant. Some people define RS5 as a polysaccharide formed by water-insoluble linear poly α-1,4-D-glucose, which cannot be degraded by α-amylase, and poly α-1,4-D-glucose can promote the formation of short-chain fatty acids in the colon. Therefore, RS5 can be used as a nutritional supplement to prevent colon cancer.

[0013] At present, the main methods for preparing resistant starch include autoclave-cooling method, screw extrusion method, enzyme debranching method, microwave radiation method, etc. The present invention intends to prepare RS2 ungelatinized natural starch by microbial fermentation method, thereby providing technical support for the preparation of health foods that help maintain healthy blood sugar levels. Summary of the invention

[0014] The purpose of the present invention is to provide a banana resistant starch and a preparation method thereof and application thereof in the preparation of health foods, so as to solve the problems existing in the above-mentioned prior art. The banana resistant starch prepared by the present invention through combined fermentation of Lactobacillus brevis and Saccharomyces kluyveri can significantly enhance the blood sugar metabolism regulating ability under the influence of high fat, and therefore can be used to prepare health foods that help maintain healthy blood sugar levels.

[0015] To achieve the above object, the present invention provides the following solutions:

[0016] The present invention provides a method for preparing banana resistant starch, comprising the following steps:

[0017] Unripe bananas are peeled, sterilized by irradiation, ground and pulped with sterile water, and passed through a 60-mesh sieve to obtain a pulp;

[0018] inoculating Lactobacillus brevis and Saccharomyces kluyveri into the slurry for fermentation to obtain a fermentation liquid;

[0019] After the fermentation liquid is allowed to stand, the supernatant is discarded, the precipitate is washed with sterile water, and then dried to obtain the banana resistant starch;

[0020] The strain numbers of the Lactobacillus brevis and the Kluyveri yeast in the China General Microbiological Culture Collection Center are CGMCC 1.2028 and CGMCC 2.3934 respectively.

[0021] Furthermore, the Lactobacillus brevis and the Saccharomyces kluyveri are inoculated in the form of a Lactobacillus brevis suspension and a Saccharomyces kluyveri suspension, respectively.

[0022] Furthermore, the inoculation ratio of the Lactobacillus brevis to the Saccharomyces kluyveri is 1:(1-1.5).

[0023] Furthermore, the inoculation ratio of the Lactobacillus brevis to the Saccharomyces kluyveri is 1:1.

[0024] Furthermore, the fermentation treatment is carried out at a temperature of 30-35°C, a time of 45-50h, and a rotation speed of 150-180r / min.

[0025] Furthermore, the drying temperature is 35-40°C.

[0026] The present invention also provides banana resistant starch prepared according to the above preparation method.

[0027] The present invention also provides the use of the banana resistant starch in preparing health food that helps maintain a healthy blood sugar level.

[0028] The invention also provides a health food which helps to maintain a healthy blood sugar level, wherein the active ingredient comprises the banana resistant starch.

[0029] Furthermore, the health food is an oral lozenge;

[0030] The oral lozenge comprises the following components by weight: 10-15 parts of stevioside, 10-15 parts of xylitol, 5-10 parts of honey, 10-15 parts of banana resistant starch, 0.1-0.5 parts of magnesium stearate, and 0.1-0.5 parts of citric acid.

[0031] The present invention discloses the following technical effects:

[0032] The present invention adopts Lactobacillus brevis and Saccharomyces kluyveri to carry out joint fermentation treatment on the slurry of unripe bananas, which can not only realize the full extraction of resistant starch, but also effectively consume non-resistant starch substances such as pectin, cellulose, protein and digestible starch in the slurry through the metabolic function of the strain, thereby effectively improving the total amount and purity of the extracted banana resistant starch.

[0033] The banana resistant starch prepared by the combined fermentation of Lactobacillus brevis and Saccharomyces kluyveri can significantly enhance the blood sugar metabolism regulation ability under the influence of high fat, and thus can be used to prepare health food that helps maintain a healthy blood sugar level. The present invention has important practical application prospects and is particularly suitable for market application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0035] Figure 1 Standard curve constructed for the determination of reducing sugars by DNS method. DETAILED DESCRIPTION

[0036] 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 should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0038] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation 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 a conflict with any incorporated document, the content of this specification shall prevail.

[0039] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0040] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0041] The strain information used in the following examples is as follows:

[0042] Lactobacillus brevis, Saccharomyces kluyveri, Saccharomyces cerevisiae and Bacillus subtilis were purchased from China General Microbiological Culture Collection Center (CGMCC), and the strain numbers are CGMCC 1.2028, CGMCC 2.3934, CGMCC2.3846 and CGMCC 1.12938, respectively.

[0043] Example 1

[0044] 1. Experimental materials

[0045] The experimental raw materials were commercially available unripe bananas with green peel.

[0046] 2. Methods

[0047] 2.1 Preparation of bacterial suspension

[0048] Lactobacillus brevis was inoculated into LB liquid medium and cultured at 37°C for 2 days. After centrifugation, it was resuspended in sterile saline to 10 8 CFU / mL, and obtain Lactobacillus brevis suspension.

[0049] Kluyveromyces was inoculated into YPD liquid medium and cultured at 30°C for 2 days. After centrifugation, the mixture was resuspended in sterile saline to 10 8 CFU / mL, and obtain Kluyveromyces suspension.

[0050] 2.2 Fermentation treatment

[0051] (1) Unripe bananas are peeled, irradiated and sterilized, and then ground and pulped with sterile water in a sterile room at a material-liquid mass ratio of 1:1.5, and then sieved through a 60-mesh sieve to obtain a slurry.

[0052] (2) 1 kg of the slurry obtained in step (1) was inoculated with a suspension of Lactobacillus brevis and a suspension of Saccharomyces kluyveri (both inoculated at 2.5%), and then fermented at 30° C. for 48 h with a rotation speed of 160 r / min.

[0053] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 40° C. to obtain 75.8 g of banana resistant starch.

[0054] Example 2

[0055] 1. Experimental materials

[0056] The experimental raw materials were commercially available unripe bananas with green peel.

[0057] 2. Methods

[0058] 2.1 Preparation of bacterial suspension

[0059] Lactobacillus brevis was inoculated into LB liquid medium and cultured at 37°C for 2 days. After centrifugation, it was resuspended in sterile saline to 10 8 CFU / mL, and obtain Lactobacillus brevis suspension.

[0060] Kluyveromyces was inoculated into YPD liquid medium and cultured at 30°C for 2 days. After centrifugation, the mixture was resuspended in sterile saline to 10 8 CFU / mL, and obtain Kluyveromyces suspension.

[0061] 2.2 Fermentation treatment

[0062] (1) Unripe bananas are peeled, irradiated and sterilized, and then ground and pulped with sterile water in a sterile room at a material-liquid mass ratio of 1:1.5, and then sieved through a 60-mesh sieve to obtain a slurry.

[0063] (2) Take 1 kg of the slurry obtained in step (1), inoculate it with a suspension of Lactobacillus brevis and a suspension of Saccharomyces kluyveri (inoculation amounts are 2% and 3%, respectively), and ferment it at 33° C. for 45 h, with the rotation speed controlled at 180 r / min.

[0064] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 35° C. to obtain 74.1 g of banana resistant starch.

[0065] Example 3

[0066] 1. Experimental materials

[0067] The experimental raw materials were commercially available unripe bananas with green peel.

[0068] 2. Methods

[0069] 2.1 Preparation of bacterial suspension

[0070] Lactobacillus brevis was inoculated into LB liquid medium and cultured at 37°C for 2 days. After centrifugation, it was resuspended in sterile saline to 10 8 CFU / mL, and obtain Lactobacillus brevis suspension.

[0071] Kluyveromyces was inoculated into YPD liquid medium and cultured at 30°C for 2 days. After centrifugation, the mixture was resuspended in sterile saline to 10 8 CFU / mL, and obtain Kluyveromyces suspension.

[0072] 2.2 Fermentation treatment

[0073] (1) Unripe bananas are peeled, irradiated and sterilized, and then ground and pulped with sterile water in a sterile room at a material-liquid mass ratio of 1:1.5, and then sieved through a 60-mesh sieve to obtain a slurry.

[0074] (2) 1 kg of the slurry obtained in step (1) was inoculated with a suspension of Lactobacillus brevis and a suspension of Saccharomyces kluyveri (both inoculated at 2.5%), and then fermented at 35° C. for 50 h with a rotation speed of 150 r / min.

[0075] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 38° C. to obtain 74.7 g of banana resistant starch.

[0076] Comparative Example 1

[0077] Same as Example 1, except that Saccharomyces kluyveri is replaced by Saccharomyces cerevisiae.

[0078] In this comparative example, 76.5 g of banana resistant starch was obtained.

[0079] Comparative Example 2

[0080] 1. Experimental materials

[0081] The experimental raw materials were commercially available unripe bananas with green peel.

[0082] 2. Methods

[0083] 2.1 Preparation of bacterial suspension

[0084] Lactobacillus brevis was inoculated into LB liquid medium and cultured at 37°C for 2 days. After centrifugation, it was resuspended in sterile saline to 10 8 CFU / mL, and obtain Lactobacillus brevis suspension.

[0085] 2.2 Fermentation treatment

[0086] (1) After irradiation sterilization, unripe bananas were ground and pulped with sterile water in a sterile room at a solid-liquid ratio of 1:1.5, and passed through a 60-mesh sieve to obtain a slurry.

[0087] (2) Take 1 kg of the slurry obtained in step (1), inoculate it with a suspension of Lactobacillus brevis (inoculation amount is 5%), and ferment it at 35° C. for 48 h, with the rotation speed controlled at 160 r / min.

[0088] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 40° C. to obtain 71.7 g of banana resistant starch.

[0089] Comparative Example 3

[0090] 1. Experimental materials

[0091] The experimental raw materials were commercially available unripe bananas with green peel.

[0092] 2. Methods

[0093] 2.1 Preparation of bacterial suspension

[0094] Kluyveromyces was inoculated into YPD liquid medium and cultured at 30°C for 2 days. After centrifugation, the mixture was resuspended in sterile saline to 10 8 CFU / mL, and obtain Kluyveromyces suspension.

[0095] 2.2 Fermentation treatment

[0096] (1) Unripe bananas are peeled, irradiated and sterilized, and then ground and pulped with sterile water in a sterile room at a solid-liquid ratio of 1:1.5, and passed through a 60-mesh sieve to obtain a slurry.

[0097] (2) Take 1 kg of the slurry obtained in step (1), inoculate it with a suspension of Saccharomyces cerevisiae (inoculation amount is 5%), and ferment it at 30° C. for 48 h, with the rotation speed controlled at 160 r / min.

[0098] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 40° C. to obtain 85.9 g of resistant starch.

[0099] Comparative Example 4

[0100] 1. Experimental materials

[0101] The experimental raw materials were commercially available unripe bananas with green peel.

[0102] 2. Methods

[0103] 2.1 Preparation of bacterial suspension

[0104] Bacillus subtilis was inoculated into LB liquid medium and cultured at 37°C for 2 days. After centrifugation, it was resuspended in sterile saline to 10 8 CFU / mL, and obtain Bacillus subtilis suspension.

[0105] 2.2 Fermentation treatment

[0106] (1) Unripe bananas are peeled, irradiated and sterilized, and then ground and pulped with sterile water in a sterile room at a solid-liquid ratio of 1:1.5, and passed through a 60-mesh sieve to obtain a slurry.

[0107] (2) After inoculating the slurry obtained in step (1) with a suspension of Bacillus subtilis (inoculation amount of 5%), fermentation was carried out at 35° C. for 48 hours, with the rotation speed controlled at 160 r / min.

[0108] (3) After the fermentation culture in step (2) was completed, the fermentation liquid was allowed to stand for 2 h, the supernatant was discarded, and the precipitate was washed three times with sterile water and dried at 40° C. to obtain 72.6 g of resistant starch.

[0109] Experimental Example 1

[0110] The content of the banana resistant starch prepared in Examples 1-3 and Comparative Examples 1-4 was detected by the following method:

[0111] (1) Weigh 10 g (100 mesh) of the resistant starch sample to be tested into a 250 mL beaker, add 50 mL of HCl-KCl buffer (pH 1.5), add 1 mL of pepsin solution, keep the temperature at 40°C for 1 h, and keep shaking continuously to remove protein in the sample;

[0112] (2) After the reaction, the mixture was taken out and cooled naturally to room temperature, the pH was adjusted to 6.0-6.4 with 2 mol / L NaOH and 0.5 mol / L HCl, 1 mL of thermostable α-amylase solution (2000 U / mL) was added, and the mixture was placed in a constant temperature water bath at 95°C for 30 min with continuous shaking to hydrolyze the digestible starch therein;

[0113] (3) Cool to room temperature, adjust the pH to 4.0-4.5 with 2 mol / L HCl and 0.5 mol / L NaOH, add 1 mL of glucose amylase solution (2000 U / mL), and incubate in a 60°C constant temperature water bath for 1 h with constant shaking to completely hydrolyze the digestible starch into glucose.

[0114] (4) Cool and centrifuge (4000 r / min, 15 min), discard the supernatant, and repeat this process three times to wash away the glucose;

[0115] (5) adding 7.5 mL of 4 mol / L KOH, heating in a water bath, and stirring to dissolve the resistant starch in the precipitate;

[0116] (6) Add 5 mL of 6 mol / L HCl to neutralize KOH, adjust the pH to 4.0-4.5 with 2 mol / L NaOH and 0.5 mol / L HCl, add 1 mL of glucoamylase solution, and place in a constant temperature water bath at 60°C for 1 h with continuous shaking to hydrolyze the dissolved starch into glucose;

[0117] (7) Cool, centrifuge (4000 r / min, 15 min), collect the supernatant, wash with water, repeat this process three times, combine the supernatants, and dilute to 100 mL in a volumetric flask with water;

[0118] (8) DNS method for determination of reducing sugar;

[0119] (9) The resistant starch content was calculated using the following formula:

[0120] Reducing sugar content (%) = (reducing sugar weight × sample dilution factor) / (sample weight × 0.5) × 100%;

[0121] Resistant starch RS content (%) = reducing sugar content (%) × 0.9.

[0122] The standard curve for the determination of reducing sugar by DNS method is shown in Figure 1 .

[0123] The test results of the banana resistant starch prepared in Example 1 and Comparative Examples 1-4 are shown in Table 1. The present invention uses Lactobacillus brevis and Kluyveri to perform a combined fermentation treatment on the slurry of unripe bananas, which not only achieves the full extraction of resistant starch, but also effectively consumes non-resistant starch substances such as pectin, cellulose, protein and digestible starch in the slurry through the metabolic function of the strain, thereby effectively improving the total amount and purity of the extracted banana resistant starch.

[0124] Table 1 Content of banana resistant starch prepared in Example 1 and Comparative Examples 1-4

[0125] Group Yield (g) Resistant starch RS content (%) Example 1 75.8 99.0 Example 2 74.1 98.6 Example 3 74.7 98.8 Comparative Example 1 76.5 88.1 Comparative Example 2 71.7 79.6 Comparative Example 3 85.9 67.1 Comparative Example 4 72.6 88.0

[0126] Experimental Example 2

[0127] 1. Experimental Materials

[0128] C57BL / 6 mice: 4 weeks old, weighing 18-20 g. During the feeding period, the animal room was set with a 12-h light-dark cycle, mice had free access to food and water, and the temperature was maintained between 21-25°C and the humidity was 50-70%.

[0129] 2. Experimental Grouping and Methods

[0130] C57BL / 6 mice were randomly divided into 7 groups, 20 mice in each group, and gavage and feeding were performed as shown in Table 2.

[0131] Table 2 Experimental groups

[0132] Grouping feed Oral gavage Example 1 High fat diet The banana resistant starch prepared in Example 1 was administered intragastricly at a dose of 10 g / kg Comparative Example 1 High fat diet The banana resistant starch prepared in comparative example 1 was administered intragastricly at a dosage of 10 g / kg Comparative Example 2 High fat diet The banana resistant starch prepared in comparative example 2 was administered intragastricly at a dosage of 10 g / kg Comparative Example 3 High fat diet The banana resistant starch prepared in comparative example 3 was administered intragastricly at a dosage of 10 g / kg Comparative Example 4 High fat diet The banana resistant starch prepared in Comparative Example 4 was administered intragastricly at a dosage of 10 g / kg Blank control Basic feed / Model Group High fat diet /

[0133] Note: High-fat feed formula: basic feed 52.5% + lard 10% + cholesterol 2% + sucrose 30% + egg yolk powder 5% + bile salt 0.5%.

[0134] After continuous gavage and feeding for 4 weeks, each group of mice was given an oral glucose tolerance test, and the blood glucose level at 0 h was measured. 15 min later, 2.5 g / kg glucose solution was gavaged again, and the blood glucose levels of the mice were measured after waiting for 0.5 h, 1.0 h and 2.0 h.

[0135] 3. Experimental results

[0136] The blood glucose test results of each group of mice are shown in Table 3. The results showed that compared with the blank control group, the blood glucose levels of the model group mice were significantly increased after intragastric administration of glucose solution (P<0.05). The blood glucose levels of the mice in Example 1 group after intragastric administration of glucose solution were significantly different from those of the mice in the model group (P<0.01). This shows that the banana resistant starch prepared in Example 1 can enhance the blood glucose metabolism regulation ability of mice under the influence of high fat.

[0137] Table 3 Blood glucose test results of mice in each group

[0138]

[0139] Example 4

[0140] An oral lozenge that helps maintain a healthy blood sugar level, comprising, by weight, 10 parts of stevioside, 15 parts of xylitol, 5 parts of honey, 10 parts of banana resistant starch prepared in Example 1, 0.5 parts of magnesium stearate, and 0.5 parts of citric acid.

[0141] Example 5

[0142] An oral lozenge that helps maintain a healthy blood sugar level, comprising, by weight, 12 parts of stevioside, 12 parts of xylitol, 8 parts of honey, 12 parts of banana resistant starch prepared in Example 1, 0.4 parts of magnesium stearate, and 0.4 parts of citric acid.

[0143] Example 6

[0144] An oral lozenge that helps maintain a healthy blood sugar level, comprising, by weight, 15 parts of stevioside, 10 parts of xylitol, 10 parts of honey, 15 parts of banana resistant starch prepared in Example 1, 0.1 part of magnesium stearate, and 0.1 part of citric acid.

[0145] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing banana resistant starch, characterized in that: The following steps are involved: Unripe bananas are peeled, sterilized by irradiation, ground and pulped with sterile water, and passed through a 60-mesh sieve to obtain a pulp; inoculating Lactobacillus brevis and Saccharomyces kluyveri into the slurry for fermentation to obtain a fermentation liquid; After the fermentation liquid is allowed to stand, the supernatant is discarded, the precipitate is washed with sterile water, and then dried to obtain the banana resistant starch; The strain numbers of the Lactobacillus brevis and the Kluyveri yeast in the China General Microbiological Culture Collection Center are CGMCC 1.2028 and CGMCC 2.3934 respectively.

2. The preparation method according to claim 1, characterized in that: The Lactobacillus brevis and the Saccharomyces kluyveri are inoculated in the form of a Lactobacillus brevis suspension and a Saccharomyces kluyveri suspension, respectively.

3. The preparation method according to claim 2, characterized in that: The inoculation ratio of the Lactobacillus brevis to the Saccharomyces kluyveri is 1:(1-1.5).

4. The preparation method according to claim 3, characterized in that: The inoculation ratio of the Lactobacillus brevis to the Saccharomyces kluyveri is 1:

1.

5. The preparation method according to claim 1, characterized in that: The fermentation temperature is 30-35°C, the fermentation time is 45-50h, and the rotation speed is 150-180r / min.

6. The preparation method according to claim 1, characterized in that: The temperature of the drying process is 35-40°C.

7. Banana resistant starch prepared according to the preparation method according to any one of claims 1 to 6.

8. Use of the banana resistant starch as claimed in claim 7 in preparing health food that helps maintain healthy blood sugar levels.

9. A health food that helps maintain healthy blood sugar levels, characterized in that: The active ingredient comprises the banana resistant starch according to claim 7.

10. The health food according to claim 9, characterized in that The health food is an oral lozenge; The oral lozenge comprises the following components by weight: 10-15 parts of stevioside, 10-15 parts of xylitol, 5-10 parts of honey, 10-15 parts of banana resistant starch, 0.1-0.5 parts of magnesium stearate, and 0.1-0.5 parts of citric acid.

Images