Preparation method and application of tartary buckwheat insoluble dietary fiber combined phenol

Abstract

The invention discloses tartary buckwheat insoluble dietary fiber additive type biscuits capable of reducing methylglyoxal and a preparation method of the tartary buckwheat insoluble dietary fiber additive type biscuits. According to the method disclosed by the invention, the tartary buckwheat bran is used as a raw material for continuous enzymolysis, so that the tartary buckwheat insoluble dietary fiber bound phenol with relatively high purity is obtained. Various phenolic substances are detected by the obtained tartary buckwheat insoluble dietary fiber combined phenol, so that the tartary buckwheat insoluble dietary fiber combined phenol has remarkable methyl glyoxal removal capacity, and most of methyl glyoxal removal capacity of residues digested by the stomach and the intestine can still be reserved, so that the tartary buckwheat insoluble dietary fiber combined phenol can continuously play a removal role in the gastrointestinal tract. The tartary buckwheat insoluble dietary fiber combined phenol is properly added into the biscuit, so that the content of methylglyoxal in the biscuit can be reduced, the intake of harmful substances in food by a human body is reduced, the occurrence of chronic diseases is slowed down, and the tartary buckwheat biscuit is beneficial to the health of the human body.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a preparation method of tartary buckwheat insoluble dietary fiber combined with phenol and application thereof. Background Art

[0002] As consumers' health awareness increases, more and more people are beginning to pay attention to harmful substances produced during food processing, especially methylglyoxal (MGO) produced in high-temperature processed foods. MGO is a highly reactive α-dicarbonyl compound, and excessive intake may lead to chronic diseases such as Alzheimer's disease, diabetes and colon cancer. However, in the processing of existing baked foods such as biscuits, the Maillard reaction and oxidative degradation of sugars at high temperatures inevitably produce more MGO, which is still a major hidden danger to food safety. Although the existing technologies such as controlling temperature and reducing reducing sugars can reduce the generation of MGO to a certain extent, they often affect the flavor and texture of the product and are difficult to promote and apply in large-scale production. Therefore, developing a technology that can effectively reduce the generation of MGO without affecting the sensory quality of food is still a major challenge for the industry. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing tartary buckwheat insoluble dietary fiber combined with phenol.

[0006] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing insoluble dietary fiber combined with phenol from bitter buckwheat, characterized in that: it comprises:

[0007] The tartary buckwheat bran was crushed and sieved, and then n-hexane was added and stirred for defatting, and then water was added and stirred to obtain a sample;

[0008] The sample is subjected to continuous enzymatic hydrolysis with amylase, amyloglucosidase and protease in sequence to obtain an enzymatic hydrolyzate;

[0009] The enzymatic hydrolysate was centrifuged, the supernatant was discarded, the residue was washed with ethanol aqueous solution until neutral, freeze-dried and passed through an 80-mesh sieve to obtain the insoluble dietary fiber-bound phenol of bitter buckwheat.

[0010] As a preferred embodiment of the preparation method of the present invention, wherein: n-hexane is added for stirring and defatting, wherein the solid-liquid ratio of tartary buckwheat bran powder to n-hexane is 1g:40ml to 1g:60ml.

[0011] As a preferred embodiment of the preparation method of the present invention, wherein: the sample is obtained by adding water and stirring, wherein the material-liquid ratio of the defatted tartary buckwheat bran powder to water is 1g:10ml to 1g:15ml.

[0012] As a preferred embodiment of the preparation method of the present invention, the sample is subjected to continuous enzymatic hydrolysis with amylase, amyloglucosidase and protease in sequence, wherein the temperature of the continuous enzymatic hydrolysis is 60-70°C, the pH of the amylase hydrolysis is 6.0, the time is 40-60min, the pH of the amyloglucosidase hydrolysis is 4.5, the time is 60-80min, and the pH of the alkaline protease hydrolysis is 8.0, and the time is 120-150min.

[0013] As a preferred embodiment of the preparation method of the present invention, the enzymatic hydrolysate is centrifuged, wherein the centrifugation condition is centrifugation at 8000 rpm for 15-20 min.

[0014] Another object of the present invention is to overcome the deficiencies in the prior art and provide a bitter buckwheat insoluble dietary fiber combined with phenol.

[0015] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of tartary buckwheat insoluble dietary fiber combined with phenol in the preparation of tartary buckwheat IDF-BP added biscuits.

[0016] As a preferred embodiment of the application of the present invention, the method for preparing the biscuits containing insoluble bitter buckwheat dietary fiber and phenol added comprises the steps of mixing sucrose, sodium bicarbonate, ammonium bicarbonate and sodium chloride in water, adding shortening, stirring and fully beating, and then adding low-gluten wheat flour and insoluble bitter buckwheat dietary fiber to prepare biscuit dough; baking the biscuit dough in an oven at 175° C. for 15 minutes, taking out the biscuits, cooling them at room temperature for 25 minutes, and then vacuum sealing and storing them.

[0017] As a preferred embodiment of the application of the present invention, the method for preparing the biscuits containing insoluble bitter buckwheat dietary fiber and phenol added comprises the steps of mixing sucrose, sodium bicarbonate, ammonium bicarbonate and sodium chloride in water, adding shortening, stirring and fully beating, and then adding low-gluten wheat flour and insoluble bitter buckwheat dietary fiber to prepare biscuit dough; baking the biscuit dough in an oven at 175° C. for 15 minutes, taking out the biscuits, cooling them at room temperature for 25 minutes, and then vacuum sealing and storing them.

[0018] As a preferred embodiment of the application of the present invention, the bitter buckwheat insoluble dietary fiber combined with phenol-added biscuits can reduce methylglyoxal by 33%.

[0019] Beneficial effects of the present invention:

[0020] (1) The present invention provides a method for extracting insoluble dietary fiber-bound phenol (IDF-BP) of tartary buckwheat. The yield of tartary buckwheat IDF-BP is 85.7±0.4% by continuously enzymatically hydrolyzing tartary buckwheat IDF-BP.

[0021] (2) Buckwheat IDF-BP is rich in rutin and quercetin, and its scavenging rate for methylglyoxal can reach 75.02±0.18%. The residue after gastrointestinal digestion still retains most of the scavenging ability. When added to biscuits, the methylglyoxal content was reduced by 33.33±1.6% compared with the biscuits without fiber added, and the optimal addition amount of 6% buckwheat IDF-BP was found. The above experimental results provide a data basis for the comprehensive utilization of buckwheat IDF-BP and provide a new way for the comprehensive utilization of buckwheat IDF-BP. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing 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 creative labor. Among them:

[0023] Figure 1 Determination of phenolic composition of tartary buckwheat IDF-BP according to an embodiment of the present invention;

[0024] Figure 2 The scavenging effect of tartary buckwheat IDF-BP and the residue of tartary buckwheat IDF-BP after gastrointestinal digestion on methylglyoxal in the simulation system according to the embodiment of the present invention;

[0025] Figure 3 The bitter buckwheat IDF-BP according to the embodiment of the present invention is added to the biscuits to reduce the methylglyoxal content in the biscuits.

[0026] Figure 4 The tartary buckwheat IDF-BP according to the comparative example of the present invention is added to biscuits to reduce the methylglyoxal content in the biscuits. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0030] The room temperature of the present invention is 25°C.

[0031] Instruments and reagents used in the examples of the present invention:

[0032] LC-20A liquid chromatograph, Shimadzu Corporation, Japan; T9 double-beam UV-visible spectrophotometer, Beijing Puxi General Instrument Co., Ltd.; ZQTY-50 shaking incubator, Shanghai Zhichu Instrument Co., Ltd.

[0033] Methylglyoxal, pepsin (2500 U / mg), pancreatin (8×USP), porcine bile salts and water-soluble vitamin E (Trolox) were purchased from Sigma-Aldrich, USA; cellulose powder was purchased from Shanghai Xianding Biotechnology Co., Ltd.; o-phenylenediamine (OPD) was purchased from Beijing Bailingwei Technology Co., Ltd.; alkaline protease (100 U / mg) was purchased from Novozymes (China) Biotechnology Co., Ltd.; amylase (20000 U / mL), starch glucose Glycosidase (100000U / mL), protocatechuic acid, p-hydroxybenzoic acid, caffeic acid, p-hydroxycinnamic acid, ferulic acid, sinapinic acid, catechin, myricetin, rutin, quercetin, kaempferol and Folin-Ciocalteu reagent were purchased from Shanghai Yuanye Biotechnology Co., Ltd.; n-hexane, ethyl acetate, ethanol, chromatographic grade acetonitrile and chromatographic grade methanol were purchased from Sinopharm Chemical Reagent Co., Ltd.; chromatographic grade formic acid was purchased from Shanghai Aladdin Reagent Co., Ltd.; buckwheat bran was collected in Daliangshan, Sichuan.

[0034] In the following examples, the components of the obtained tartary buckwheat IDF-BP were determined, and the specific determination method is as follows:

[0035] Protein determination method: The protein content in insoluble fiber of buckwheat was determined by Kjeldahl method.

[0036] Determination of total phenols: The total phenol content in insoluble buckwheat fiber was determined by the Folin phenol method, with gallic acid as the standard.

[0037] The standard sample was used to draw a standard curve and calculate the total phenol content in the insoluble fiber of buckwheat.

[0038] Determination of total starch content: A total starch kit was used to determine the total starch content in the insoluble dietary fiber of buckwheat.

[0039] The components of the tartary buckwheat IDF-BP obtained in this example were determined, and the results are shown in Table 1.

[0040] Table 1

[0041]

[0042] Example 1

[0043] This embodiment provides a method for extracting IDF-BP from tartary buckwheat bran, comprising the following steps:

[0044] (1) Tartary buckwheat bran was crushed and passed through an 80-mesh sieve, and n-hexane (1:40, m / v) was added. After defatting by stirring at 220 rpm, the mixture was placed in a fume hood overnight to evaporate the organic reagent.

[0045] (2) Stir the defatted sample and water at a solid-liquid ratio of 1:12 at 90°C for 10 min.

[0046] (3) Continuous enzymatic hydrolysis was performed at 60°C using 0.5% amylase (pH 6.0, 50 min), 0.4% amyloglucosidase (pH 4.5, 60 min) and 0.7% protease (pH 8.0, 120 min) to remove starch and protein in the sample.

[0047] (4) The enzymatic hydrolysate was centrifuged at 8000 rpm for 15 min, the supernatant was discarded, and the residue was washed with 80% ethanol aqueous solution to remove free phenol, and then washed with distilled water until neutral.

[0048] (5) After freeze-drying (-40°C) for 48 h, the tartary buckwheat IDF-BP was ground through an 80-mesh sieve and stored at -20°C for later use.

[0049] Example 2

[0050] This embodiment provides a method for determining the scavenging ability of tartary buckwheat IDF-BP extracted in embodiment 1 on methylglyoxal, comprising the following steps:

[0051] 1.0mmol / L methylglyoxal was prepared with phosphate buffer (0.1mol / L, pH 7.0) and mixed with 19mg buckwheat IDF-BP or fiber powder (blank) to a final volume of 2mL. After sealing with nitrogen, the mixture was reacted in the dark at 37℃ and 100rpm for 12h. After the reaction, 1mL acetonitrile was added to the mixture and vortexed for 30s, centrifuged at 10000rpm for 15min, and 1mL supernatant was taken to determine the content of methylglyoxal remaining after the removal of buckwheat IDF-BP.

[0052] For the derivatization of methylglyoxal, 1 mL of the supernatant was taken and thoroughly mixed with a 0.2% OPD aqueous solution, and the mixture was derivatized for 3 h at room temperature in the dark. After derivatization, the mixture was filtered through a 0.22 μm filter membrane for detection.

[0053] Determination method: The content of MGO derivatives was determined using LC-20A HPLC.

[0054] Chromatographic conditions: the chromatographic column was Agilent Poroshell 120SB-AQ C18 (100 mm × 3.0 mm, 2.7 μm); the column temperature was 40°C; the flow rate was 0.4 mL / min; the injection volume was 5 μL; the mobile phase A was 0.1% formic acid in water; the mobile phase B was acetonitrile containing 0.1% formic acid; for the determination of methylglyoxal, the gradient elution program was 0-3 min, 10% B; 3-8 min, 10-25% B; 8-15 min, 25-80% B; 17-18 min, 80-10% B; 18-27 min, 10% B; the detection wavelength was 315 nm;

[0055] The methylglyoxal clearance rate was calculated by the following formula:

[0056] Methylglyoxal removal rate (%) = (1-A 1 / A 0 )×100%;

[0057] Among them, A 0 and A 1 Represent the contents of methylglyoxal in the blank control group and the experimental group, respectively.

[0058] Comparative Example 1

[0059] The scavenging ability of gastric digestion residues on methylglyoxal:

[0060] 1 g of bitter buckwheat IDF-BP was mixed with 4 mL of distilled water, and then 4 mL of simulated oral digestive fluid, 25 μL of calcium chloride dihydrate (0.3 mol / L) and 0.975 mL of distilled water were added and mixed thoroughly. The pH was adjusted to 7.0 with 5 mol / L sodium hydroxide. After sealing with nitrogen, the mixture was placed in a shaking incubator (37 ° C, 220 rpm) and incubated in the dark for 5 min.

[0061] For the in vitro gastric digestion stage, 8 mL of simulated gastric digestion fluid, 5 μL of calcium chloride dihydrate (0.3 mol / L) and 0.928 mL of distilled water were added to 10 mL of oral digesta, and the pH was adjusted to 3.0 with 6 mol / L hydrochloric acid after mixing. Then, 0.667 mL of pepsin solution (2000 U / mL) was added, and the mixture was sealed with nitrogen and placed in a shaking incubator (37 °C, 200 rpm) in the dark for incubation for 2 h.

[0062] The in vitro gastric digestion mixture was centrifuged (4°C, 10,000 rpm, 15 min), and the precipitate was washed with 80% ethanol and distilled water, and the gastric digestion residue obtained after freeze-drying was stored at -20°C for future use. Other conditions were the same as in Example 2, and the methylglyoxal scavenging ability was determined.

[0063] Comparative Example 2

[0064] The scavenging ability of gastrointestinal digestion residues on methylglyoxal:

[0065] For the in vitro intestinal digestion stage, 8 mL of simulated intestinal digestion fluid, 40 μL of calcium chloride dihydrate (0.3 mol / L) and 3.16 mL of distilled water were added to 20 mL of gastric digesta, mixed and adjusted to pH 7.0 with 5 mol / L sodium hydroxide, then 5 mL of pancreatic enzyme (100 U / mL) and 2.5 mL of bile salt (10 mmol / L) were added, and the mixture was sealed with nitrogen and placed in a shaking incubator (37 °C, 200 rpm) in the dark for 2 h.

[0066] The in vitro gastrointestinal digestion mixture was centrifuged (4°C, 10,000 rpm, 15 min), and the precipitate was washed with 80% ethanol and distilled water, and the gastrointestinal digestion residue obtained after freeze-drying was stored at -20°C for future use. Other conditions were the same as in Example 2, and the methylglyoxal scavenging ability was determined.

[0067] The configurations of the oral digestive juice, gastric digestive juice, and small intestinal digestive juice in Comparative Examples 1 and 2 are shown in Table 2.

[0068] Table 2

[0069]

[0070] Comparative Example 3

[0071] The removal ability of phenol-free IDF on methylglyoxal:

[0072] Preparation of dephenolized IDF: 1 g of bitter buckwheat IDF-BP was mixed with 20 mL of sodium hydroxide solution (4 mol / L), and then hydrolyzed at room temperature in the dark for 4 h after nitrogen sealing. The hydrolyzate was centrifuged at 5000 rpm for 10 min and freeze-dried to obtain alkaline hydrolyzed bitter buckwheat IDF. Acid hydrolysis was used to further remove the bound phenols in the alkaline hydrolyzed bitter buckwheat IDF.

[0073] 1 g of alkaline hydrolyzed tartary buckwheat IDF was weighed, 20 mL of methanol-sulfuric acid solution (90:10, v / v) was added, and the mixture was sealed with nitrogen and hydrolyzed at 85°C in the dark for 20 h. After centrifugation (8000 rpm, 15 min), the hydrolyzed residue was washed with 80% ethanol and distilled water until neutral, and freeze-dried to obtain dephenolized tartary buckwheat IDF. Other conditions were the same as those in Example 2.

[0074] The measurement results of Example 2 and Comparative Examples 1 to 3 are as follows Figure 1 As shown, the bitter buckwheat IDF-BP extracted in Example 1 can effectively remove methylglyoxal in the reaction system. The removal rate can reach 75.02±0.18%, and the removal rate of MGO by the fiber after dephenolization is only 14.10±1.19%, indicating that the removal effect on MGO is mainly due to the phenolic substances combined with phenol in the bitter buckwheat insoluble fiber. And the residue after simulated gastrointestinal digestion still retains most of the methylglyoxal removal ability, indicating that the methylglyoxal removal effect can continue to play a role in the gastrointestinal tract.

[0075] Example 3

[0076] This example is a determination of the phenolic composition of tartary buckwheat IDF-BP, comprising the following steps:

[0077] 1 g of bitter buckwheat IDF-BP was mixed with 20 mL of sodium hydroxide solution (4 mol / L), and then hydrolyzed at room temperature in the dark for 4 h after nitrogen sealing. After alkaline hydrolysis, the pH was adjusted to 2.0 with hydrochloric acid (6 mol / L), and then extracted with ethyl acetate for 5 times. The combined extracts were rotary evaporated to dryness at 35 °C, reconstituted with 80% methanol aqueous solution, and stored at -20 °C in the dark.

[0078] The composition of bound phenols was analyzed by Acquity ultra-performance liquid chromatography triple quadrupole tandem mass spectrometry (UPLC-QQQ-MS / MS).

[0079] Chromatographic conditions: The column was Agilent Poroshell 120SB-AQ C18 (100mm×3.0mm, 2.7μm); the mobile phase A was 0.1% formic acid in water; the mobile phase B was acetonitrile containing 0.1% formic acid; the gradient elution program was 0min, 5% B; 10min, 15% B; 20min, 30% B; 30min, 70% B; 35min, 90% B; the column temperature was 35℃; the flow rate was 0.4mL / min; the injection volume was 5μL. Buckwheat IDF-BP was identified by comparing the retention time with the corresponding polyphenol standards, and the standard curve was established using the corresponding polyphenol standards for external standard method quantification.

[0080] The results of the test are as follows Figure 2 As shown in the figure, the phenolic substances detected include protocatechuic acid (1), p-hydroxybenzoic acid (2), caffeic acid (3), p-hydroxycinnamic acid (4), ferulic acid (5), sinapinic acid (6), catechin (7), myricetin (8), rutin (9), quercetin (10), and kaempferol (11). The specific contents are shown in Table 3.

[0081] Table 3 Phenolic composition of buckwheat IDF-BP (μg / g)

[0082]

[0083] Example 4

[0084] This embodiment is a method for preparing tartary buckwheat IDF-BP added biscuits, comprising the following steps:

[0085] Control biscuit recipe: 80g low-gluten wheat flour, 20g shortening, 30g sucrose, 0.5g sodium bicarbonate, 0.3g ammonium bicarbonate, 1g sodium chloride and 15g water.

[0086] Preparation method of tartary buckwheat IDF-BP added biscuits: 2% to 10% tartary buckwheat IDF-BP / dephenolized fiber (IDF) replaces wheat flour, and other conditions are the same as the control biscuits.

[0087] Sucrose, sodium bicarbonate, ammonium bicarbonate and sodium chloride were mixed in water, shortening was added, stirred and fully beaten, and low-gluten wheat flour and bitter buckwheat insoluble dietary fiber were added to prepare biscuit dough. The biscuit dough (diameter 50 mm, thickness 3 mm) was placed in an oven at 175°C and baked for 15 minutes. The biscuits were taken out and cooled at room temperature for 25 minutes and then vacuum sealed for storage.

[0088] The method for determining the content of methylglyoxal in biscuits is as follows:

[0089] Take 1g of biscuits, grind and dry to constant weight, defatted and passed through 80 mesh sieve, add 2ml methanol to extract repeatedly, add 500μL of Carrez I (prepared by dissolving 15g potassium hexacyanoferrate trihydrate in 100mL distilled water) and Carrez II (prepared by dissolving 30g zinc sulfate in 100mL distilled water) to remove protein, vortex for 2min and centrifuge at 10000rpm for 5min to remove protein in the sample. 200μL of supernatant, 400μL of phosphate buffer (pH 7.0) and 400μL of OPD solution (0.2%) are fully mixed and derivatized at room temperature in the dark for 3h. The liquid phase determination conditions refer to Example 2.

[0090] The results are as follows Figure 3 As shown in the results, it was found that there was almost no significant difference in the content of methylglyoxal between dephenolized fiber and blank biscuits, while the removal rate of methylglyoxal by biscuits with the addition of 2% to 6% IDF-BP was more obvious with the increase of fiber dosage, up to 33.30±1.60%, but when added to 8% to 10% fiber biscuits, the content of methylglyoxal did not continue to decrease significantly, indicating that the capture capacity of IDF-BP for methylglyoxal may be limited. In addition, some literature shows that it may be because the excessive addition of phenolic substances will promote oxidation and promote the formation of methylglyoxal, resulting in the fact that the content of methylglyoxal did not decrease significantly in the end. At the same time, 6% bitter buckwheat IDF-BP was determined to be the optimal addition amount for making biscuits.

[0091] Comparative Example 1

[0092] Control biscuit recipe: 80g low-gluten wheat flour, 25g shortening, 35g sucrose, 0.5g sodium bicarbonate, 0.3g ammonium bicarbonate, 1g sodium chloride and 12g water.

[0093] Preparation method of tartary buckwheat IDF-BP added biscuits: 2% to 12% tartary buckwheat IDF-BP / dephenolized fiber (IDF) replaces wheat flour, and bakes in an oven at 180° C. for 12 minutes. The other conditions for determining methylglyoxal in the biscuits are the same as above.

[0094] The results are as follows Figure 4 As shown, the scavenging effect of methylglyoxal on biscuits with the addition of 2% to 8% IDF-BP decreased with the increase of fiber dosage, reaching 28.49±2.57%, but there was no significant change in the methylglyoxal content when added to 8% to 12% fiber biscuits.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing tartary buckwheat insoluble dietary fiber combined with phenol, characterized in that: include, The tartary buckwheat bran was crushed and sieved, and then n-hexane was added and stirred for defatting, and then water was added and stirred to obtain a sample; The sample is subjected to continuous enzymatic hydrolysis with amylase, amyloglucosidase and protease in sequence to obtain an enzymatic hydrolyzate; The enzymatic hydrolysate was centrifuged, the supernatant was discarded, the residue was washed with ethanol aqueous solution until neutral, freeze-dried and passed through an 80-mesh sieve to obtain the insoluble dietary fiber-bound phenol of bitter buckwheat.

2. The preparation method according to claim 1, characterized in that: The process of adding n-hexane and stirring for defatting is carried out, wherein the solid-liquid ratio of tartary buckwheat bran powder to n-hexane is 1g:40ml-1g:60ml.

3. The preparation method according to claim 1, characterized in that: The sample is obtained by adding water and stirring, wherein the material-liquid ratio of the defatted tartary buckwheat bran powder to water is 1g:10ml-1g:15ml.

4. The preparation method according to claim 1, characterized in that: The sample is subjected to continuous enzymatic hydrolysis in sequence using amylase, amyloglucosidase and protease, wherein the temperature of the continuous enzymatic hydrolysis is 60-70°C, the pH of the amylase hydrolysis is 6.0, the time is 40-60min, the pH of the amyloglucosidase hydrolysis is 4.5, the time is 60-80min, and the pH of the alkaline protease hydrolysis is 8.0, and the time is 120-150min.

5. The preparation method according to claim 1, characterized in that: The enzymatic hydrolysate is centrifuged, wherein the centrifugation condition is centrifugation at 8000 rpm for 15-20 min.

6. Tartary buckwheat insoluble dietary fiber-bound phenol obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the tartary buckwheat insoluble dietary fiber combined with phenol as claimed in claim 6 in preparing tartary buckwheat IDF-BP added biscuits.

8. The use according to claim 7, characterized in that: The formula of the bitter buckwheat insoluble dietary fiber combined with phenol added biscuits, The invention comprises 80g of low-gluten wheat flour mixed with tartary buckwheat insoluble dietary fiber-bound phenol, 20g of shortening, 30g of sucrose, 0.5g of sodium bicarbonate, 0.3g of ammonium bicarbonate, 1g of sodium chloride and 15g of water, wherein the tartary buckwheat insoluble dietary fiber-bound phenol accounts for 2% to 10% of the mass of the low-gluten wheat flour; and the tartary buckwheat insoluble dietary fiber-bound phenol is prepared by the preparation method according to any one of claims 1 to 5.

9. The use according to claim 7, characterized in that: The method for preparing the biscuits containing insoluble bitter buckwheat dietary fiber and phenol addition comprises the steps of mixing sucrose, sodium bicarbonate, ammonium bicarbonate and sodium chloride in water, adding shortening, stirring and fully beating the mixture, and then adding low-gluten wheat flour and insoluble bitter buckwheat dietary fiber to prepare biscuit dough; baking the biscuit dough in an oven at 175° C. for 15 minutes, taking out the biscuits, cooling them at room temperature for 25 minutes, and then vacuum-sealing and storing them.

10. The use according to claim 9, characterized in that: The bitter buckwheat insoluble dietary fiber combined with phenol added biscuits can reduce methylglyoxal by 33.30±1.60%.

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