Resistant dextrin and method for preparing the same

Abstract

The application discloses resistant dextrin and a preparation method thereof. The preparation method of the resistant dextrin comprises the following steps: adding inorganic acid into starch milk to perform acid hydrolysis, so as to obtain a hydrolysis solution; (b) adding mesophilic amylase and glucoamylase into the hydrolysis solution to perform enzymolysis, so as to obtain an enzymolysis solution; (c) adding organic acid into the enzymolysis solution to perform a polymerization reaction, so as to obtain a crude resistant dextrin; and (d) purifying the crude resistant dextrin. The resistant dextrin prepared by the preparation method has high yield and purity, and has no bad flavor.

Description

Technical Field

[0001] This application relates to the field of starch deep processing technology, and in particular to a resistant dextrin and its preparation method. Background Technology

[0002] In recent years, with the development of the catering industry, people's diets have included a large amount of low-fiber, high-calorie foods, leading to an increased likelihood of developing chronic diseases such as diabetes and cardiovascular disease. Since dietary fiber promotes the absorption of micronutrients, lowers blood sugar, and regulates intestinal function, increasing its intake can promote good health.

[0003] Resistant dextrin is a water-soluble dietary fiber prepared from starch. Its unique structure endows it with excellent physicochemical properties such as good water solubility, low solution viscosity, acid resistance, and heat resistance. Due to its good processing properties and nutritional characteristics, resistant dextrin is widely used in health products, meal replacement products, dairy products, beverages, meat products, and other industries.

[0004] Currently, resistant dextrin is generally produced by dry-heating starch through acid hydrolysis and high-temperature polymerization to produce crude pyrodextrin. This crude pyrodextrin is then enzymatically hydrolyzed, followed by desalting, decolorizing, concentrating, purifying, and drying using ion exchange resin to obtain the final resistant dextrin product. The main drawbacks of this method are low yield, low purity, and undesirable flavor in the product. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for preparing resistant dextrin and the resistant dextrin obtained therefrom, which can effectively improve the yield and purity of resistant dextrin and reduce the unpleasant flavor of the product.

[0006] One aspect of this application provides a method for preparing resistant dextrin, characterized by comprising the following steps:

[0007] (a) Add inorganic acid to starch milk to perform acidification and hydrolysis, and obtain hydrolysate;

[0008] (b) Add medium-temperature amylase and glucoamylase to the hydrolysate for enzymatic hydrolysis to obtain the hydrolysate;

[0009] (c) Adding an organic acid to the enzymatic hydrolysate to carry out a polymerization reaction, yielding crude resistant dextrin; and

[0010] (d) The crude resistant dextrin is purified.

[0011] In some embodiments of this application, the inorganic acid is an inorganic acid solution, and the inorganic acid solution is added at a ratio of 5% to 10% of the dry basis mass of the starch used in preparing the starch milk, based on the dry basis mass of the starch used in preparing the starch milk.

[0012] In some embodiments of this application, step (a) further includes adding sucrose to the starch milk, wherein the mass of the sucrose is 5% to 10% of the dry basis mass of the starch used in preparing the starch milk.

[0013] In some embodiments of this application, the acidification and hydrolysis time is 4 to 8 hours.

[0014] In some embodiments of this application, based on the dry weight of the starch used in preparing the starch milk, the amount of medium-temperature amylase added is 0.01% to 0.10% of the dry weight, and the amount of glucoamylase added is 0.02% to 0.15% of the dry weight.

[0015] In some embodiments of this application, the enzymatic hydrolysis satisfies at least one of the following features (1) to (3):

[0016] (1) The enzymatic hydrolysis temperature is 50℃~65℃;

[0017] (2) The enzymatic hydrolysis time is 2 to 4 hours;

[0018] (3) The pH of the enzymatic hydrolysis is 5 to 6.

[0019] In some embodiments of this application, the mass of the organic acid is calculated to be 1% to 5% of the dry weight of the starch used in preparing the starch milk.

[0020] In some embodiments of this application, the polymerization reaction satisfies at least one of the following features (4) to (6):

[0021] (4) The polymerization reaction temperature is 110℃~130℃;

[0022] (5) The polymerization reaction takes 2 to 5 hours;

[0023] (6) The polymerization reaction is carried out under negative pressure, and the negative pressure is 0.085MPa to 0.10MPa.

[0024] In some embodiments of this application, the inorganic acid includes one or more of hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid.

[0025] In some embodiments of this application, the organic acid includes one or more of citric acid, malic acid, tartaric acid, and oxalic acid.

[0026] In another aspect of this application, a resistant dextrin prepared by the above-described method is provided.

[0027] Compared with the prior art, this application has at least the following beneficial effects:

[0028] The preparation method provided in this application first involves acidifying and hydrolyzing starch with inorganic acids, followed by further enzymatic hydrolysis to generate a large number of random small molecule products. These products then undergo polymerization under the catalysis of organic acids, thereby generating the indigestible component (resistant component). Compared with traditional processes, this method for preparing resistant dextrin avoids the dry-heat reaction process for preparing charred dextrin, and the reaction conditions are milder. Therefore, it can effectively reduce the generation of undesirable flavors and, furthermore, improve the yield and purity of resistant dextrin. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of a method for preparing resistant dextrin according to one embodiment. Detailed Implementation

[0031] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0035] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0037] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0038] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] Resistant dextrin is a soluble dietary fiber containing α-1,2-glycosidic bonds, α-1,3-glycosidic bonds, and other indigestible components. Traditionally, it is produced from starch, which is hydrolyzed using inorganic acids, followed by heat treatment to repolymerize the molecules and generate pyrodextrin. Then, enzymatic treatment is used to break down the digestible components (non-resistant components) of the pyrodextrin to obtain the indigestible components (resistant components). Subsequent purification and refining yield the final resistant dextrin product.

[0040] However, in the traditional process of preparing pyrodextrin through inorganic acid acidification followed by heat treatment, the reaction is vigorous due to the presence of inorganic acids and high temperatures (generally above 150°C), resulting in various side reactions and unpleasant flavors in the produced resistant dextrin. Furthermore, the yield and purity of resistant dextrin are also low.

[0041] Based on this, please refer to Figure 1 This application provides a method for preparing resistant dextrin, comprising the following steps:

[0042] (a) Add inorganic acid to starch milk to perform acidification and hydrolysis, and obtain hydrolysate;

[0043] (b) Add medium-temperature amylase and glucoamylase to the hydrolysate for enzymatic hydrolysis to obtain the hydrolysate;

[0044] (c) Adding an organic acid to the enzymatic hydrolysate to carry out a polymerization reaction, yielding crude resistant dextrin; and

[0045] (d) The crude resistant dextrin is purified.

[0046] The above-mentioned method for preparing resistant dextrin involves acidifying and hydrolyzing starch with inorganic acids, followed by further enzymatic hydrolysis to generate a large number of random small molecule products. These products then undergo polymerization under the catalysis of organic acids, resulting in the formation of a difficult-to-digest component (resistant component). Compared with traditional processes, this method avoids the dry-heat reaction process used to prepare pyrodextrin. The polymerization reaction temperature in this application is only 110–130°C, and the reaction system is liquid, resulting in milder reaction conditions. Therefore, it can effectively reduce the generation of undesirable flavors and further improve the yield and purity of resistant dextrin.

[0047] Starch milk has a meaning known in the art; it is prepared by mixing starch and water in a certain proportion. In some embodiments, the concentration of starch milk is 30% to 40%. Understandably, "a concentration of 30% to 40% starch milk" specifically means that the dry basis (starch) mass content of the starch milk is 30%, 32%, 34%, 35%, 36%, 38%, 40%, or any value between these values.

[0048] In some embodiments, the starch milk includes one or more of corn starch milk, potato starch milk, and tapioca starch milk.

[0049] In some embodiments, the inorganic acid is an inorganic acid solution, calculated based on the dry basis mass of the starch used in the preparation of starch milk. The inorganic acid solution is added at a total solute mass of 5% to 10% of the dry basis mass, that is, the total solute mass of the inorganic acid is 5%, 6%, 7%, 8%, 9%, 10% of the dry basis mass and any value therebetween.

[0050] In some embodiments, step (a) further includes adding sucrose to the starch slurry. Optionally, the mass of sucrose is calculated based on the dry weight of the starch used in making the starch slurry, and is 5%, 6%, 7%, 8%, 9%, 10% of the dry weight, or any value between therewith. The sucrose can be hydrolyzed under acidic conditions to exist in three forms: sucrose, glucose, and fructose. It can then be combined with the products of starch hydrolysis to synthesize resistant dextrin, thereby increasing the yield of resistant dextrin.

[0051] In some implementations, the acid hydrolysis time is 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 8 hours, and any value between them.

[0052] Without limitation, inorganic acids include one or more of hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid.

[0053] In some embodiments, the amount of mesophilic amylase added is calculated based on the dry weight of the starch used in preparing the starch milk, and is 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10% of the dry weight, and any value between them.

[0054] In some embodiments, the amount of glucoamylase added is calculated based on the dry weight of the starch used in preparing the starch milk, and is 0.02%, 0.04%, 0.06%, 0.08%, 0.10%, 0.13%, 0.15% of the dry weight, and any value between them.

[0055] In some embodiments, the enzymatic hydrolysis temperature in step (b) is 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 65°C, and any value between them.

[0056] In some implementations, the enzymatic hydrolysis time in step (b) is 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, and any value between them.

[0057] In some implementations, the pH value of the enzymatic hydrolysis in step (b) is any value between 5 and 6.

[0058] In some embodiments, the mass of the organic acid is calculated based on the dry weight of the starch used in preparing the starch milk, and is 1%, 2%, 3%, 4%, 5% of the dry weight, or any value between them.

[0059] In some embodiments, the polymerization temperature is 110°C, 115°C, 118°C, 120°C, 125°C, 128°C, or 130°C.

[0060] In some implementations, the polymerization reaction time is 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, and any value between them.

[0061] In some embodiments, the polymerization reaction is carried out under negative pressure. Optionally, the negative pressure is 0.085 MPa, 0.09 MPa, 0.095 MPa, 0.1 MPa, or any value between them.

[0062] Without limitation, organic acids include one or more of citric acid, malic acid, tartaric acid, and oxalic acid. Adding organic acids can catalyze polymerization reactions.

[0063] The second aspect of this application also provides a resistant dextrin prepared by the method for preparing resistant dextrin provided in any embodiment of the first aspect above. This resistant dextrin has high purity, i.e., a high content of resistant components, and a high yield, with significantly reduced undesirable flavor.

[0064] The following are specific embodiments. They are intended to provide further detailed explanation of this application to help those skilled in the art and researchers to better understand it. The technical conditions and other details do not constitute any limitation on this application. Any modifications made within the scope of the claims of this application are within the protection scope of the claims. Where techniques or conditions are not specified in the embodiments, they are performed according to the description above, or according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or products that can be synthesized using conventional methods from commercially available products.

[0065] Example 1

[0066] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add 30% hydrochloric acid solution (the amount of hydrochloric acid added should be 7.5% of the dry weight of corn starch by weight of the total hydrochloric acid solute), and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of corn starch amylase and 0.04% of the dry weight of corn starch glucoamylase, react at 60℃ for 3 hours, then add 5% of the dry weight of corn starch citric acid (citric acid is a solid, just weigh the corresponding mass directly), react at 120℃ and 0.10 MPa negative pressure for 2 hours to obtain crude resistant dextrin, then desalt and decolorize through resin, chromatographic purification, concentration, and drying to obtain the resistant dextrin product.

[0067] Example 2

[0068] The preparation method is basically the same as in Example 1, except that sucrose is further added to the starch milk. The specific steps are as follows:

[0069] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (5% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of corn starch amylase and 0.04% of the dry weight of corn starch glucoamylase, react at 60℃ for 3 hours, then add 5% of the dry weight of corn starch citric acid, and react at 120℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin. Then, desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0070] Example 3

[0071] The preparation method is basically the same as in Example 2, except that the amount of sucrose added is 8% of the dry weight of the corn starch. The specific steps are as follows:

[0072] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (8% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of corn starch amylase and 0.04% of the dry weight of corn starch glucoamylase, react at 60℃ for 3 hours, then add 5% of the dry weight of corn starch citric acid, react at 120℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin, then desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0073] Example 4

[0074] The preparation method is basically the same as in Example 2, except that the amount of sucrose added is 10% of the dry weight of the corn starch. The specific steps are as follows:

[0075] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (10% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of corn starch amylase and 0.04% of the dry weight of corn starch glucoamylase, react at 60℃ for 3 hours, then add 5% of the dry weight of corn starch citric acid, react at 120℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin, then desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0076] Example 5

[0077] The preparation method is basically the same as in Example 2, except that the amount of sucrose added is 15% of the dry weight of the corn starch. The specific steps are as follows:

[0078] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (15% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of corn starch amylase and 0.04% of the dry weight of corn starch glucoamylase, react at 60℃ for 3 hours, then add 5% of the dry weight of corn starch citric acid, react at 120℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin, then desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0079] Example 6

[0080] The preparation method is basically the same as in Example 2, except that in the enzymatic hydrolysis process, medium-temperature amylase is added first for 1 hour, followed by the addition of glucoamylase. The specific steps are as follows:

[0081] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (8% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Adjust the pH to 5.0, add 0.02% of the dry weight of corn starch amylase, react at 60℃ for 1 hour, then add 0.04% glucoamylase, react for 2 hours, then add 5% of the dry weight of corn starch citric acid, react at 120℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin. Then, desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0082] Example 7

[0083] Weigh 1 kg of potato starch, adjust the starch milk concentration to 30% with water, add sucrose (10% of the dry weight of potato starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 8% of the dry weight of potato starch) to the potato starch milk, and acidify and hydrolyze for 4 hours. Adjust the pH to 5.0, and simultaneously add 0.04% of the dry weight of potato starch amylase and 0.06% of the dry weight of potato starch glucoamylase, react at 50℃ for 4 hours, then add 3% of the dry weight of potato starch malic acid, react at 130℃ and 0.10 MPa for 2 hours to obtain crude resistant dextrin, then desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0084] Example 8

[0085] Weigh 1 kg of cassava starch, adjust the starch milk concentration to 40% with water, add sucrose (10% of the dry weight of the cassava starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of the hydrochloric acid solute is 10% of the dry weight of the cassava starch) to the cassava starch milk, and acidify and hydrolyze for 8 hours. Adjust the pH to 5.0, and simultaneously add 0.05% of the dry weight of cassava starch amylase and 0.08% of the dry weight of cassava starch glucoamylase, react at 50℃ for 3 hours, then add 3% of the dry weight of cassava starch oxalic acid, react at 130℃ and 0.10 MPa for 3 hours to obtain crude resistant dextrin, then desalt and decolorize using resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0086] Comparative Example 1

[0087] The preparation method is basically the same as in Example 2, except that the enzymatic hydrolysis step is omitted. The specific steps are as follows:

[0088] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (5% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch) to the starch slurry, and acidify and hydrolyze for 6 hours. Then add 5% citric acid by weight of corn starch, and react at 120℃ and 0.10 MPa negative pressure for 2 hours to obtain crude resistant dextrin. Then, desalt and decolorize through resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0089] Comparative Example 2

[0090] The preparation method is basically the same as in Example 2, except that after acidification and hydrolysis, an organic acid is added first to carry out the polymerization reaction, followed by enzymatic hydrolysis. The specific steps are as follows:

[0091] Weigh 1 kg of corn starch, adjust the starch slurry concentration to 35% with water, add sucrose (5% of the dry weight of corn starch) and 30% hydrochloric acid solution (the amount of hydrochloric acid solution added is such that the total mass of hydrochloric acid solute is 7.5% of the dry weight of corn starch), acidify and hydrolyze for 6 hours, then neutralize. Next, add 5% citric acid (by dry weight of corn starch), and react at 120℃ and 0.10 MPa for 2 hours. Then adjust the pH to 5.0, and simultaneously add 0.02% medium-temperature amylase and 0.04% glucoamylase (by dry weight of corn starch), and react at 60℃ for 3 hours. Obtain the resistant dextrin product through resin desalting, decolorization, chromatographic purification, concentration, and drying.

[0092] Comparative Example 3

[0093] Weigh 1 kg of corn starch, add water to adjust the starch slurry concentration to 35%, add hydrochloric acid solution (7.5% of the dry weight of corn starch), filter, pre-dry until the moisture content is below 5%, and react at 170℃ for 4 hours to obtain pyrodextrin product. Prepare a 40% pyrodextrin solution, adjust the pH to 5.0, and simultaneously add 0.02% of the dry weight of pyrodextrin amylase and 0.04% of the dry weight of corn starch glucoamylase. React at 60℃ for 3 hours to inactivate the enzymes and obtain crude resistant dextrin. Then, desalt and decolorize using resin, purify and concentrate by chromatography, and dry to obtain the resistant dextrin product.

[0094] Test case

[0095] The yield and purity of the resistant dextrins prepared in Examples 1-8 and Comparative Examples 1-3 were tested. The test conditions or standards for each performance test item were as follows:

[0096] 1. Production

[0097] Yield (%) = Weight of resistant dextrin product / (weight of starch + weight of sucrose) * 100.

[0098] 2. Purity (resistance component content %)

[0099] The total dietary fiber content in a product was determined according to the second method, enzyme gravimetric-liquid chromatography, in GB / T22224-2008 "Determination of Dietary Fiber in Food - Enzyme Gravimetric Method and Enzyme Gravimetric-Liquid Chromatography".

[0100] 3. Color Inspection Indicators

[0101] Whiteness was measured using the WSB-VI intelligent whiteness meter (Hangzhou Daji Optoelectronic Instruments).

[0102] 4. Sensory evaluation

[0103] A directional pairwise comparison test method was used. A 1.5% resistant dextrin solution was prepared, and a panel of 20 people was selected to conduct sensory evaluations of the two groups of samples, judging the bitterness intensity in the sample solutions and forcibly selecting the sample with the stronger bitterness. If more than 15 people selected the same sample, it was considered that there was a significant difference in flavor between the samples at a significance level of α = 0.05, and the selected sample was more bitter than the other sample.

[0104] The test results are shown in Table 1:

[0105] Table 1

[0106] Example 1 50.25 85.71 72.1 No obvious bitterness Example 2 71.37 86.36 72.6 No obvious bitterness Example 3 75.88 85.34 71.9 No obvious bitterness Example 4 77.65 86.77 71.5 No obvious bitterness Example 5 73.46 86.54 70.9 No obvious bitterness Example 6 67.58 76.44 71.4 No obvious bitterness Example 7 76.42 86.65 70.3 No obvious bitterness Example 8 75.67 81.32 72.2 No obvious bitterness Comparative Example 1 60.49 65.94 69.4 No obvious bitterness Comparative Example 2 62.56 78.86 70.6 No obvious bitterness Comparative Example 3 44.65 80.19 55.6 It has a distinct bitter taste

[0107] As shown in Table 1 above, compared with Comparative Examples 1-3, the resistant dextrin prepared by the methods provided in Examples 1-8 showed a significant improvement in both yield and purity. This indicates that enzymatic hydrolysis further breaks down the raw materials into smaller molecules, which are then removed by subsequent purification. Without the enzymatic hydrolysis step, the yield of the resistant dextrin product and the content of the resistant components (i.e., purity) in the resistant dextrin product would both decrease. Enzymatic hydrolysis to further generate smaller molecules, followed by polymerization, can further improve the yield and purity of resistant dextrin. Resistant dextrin produced using the traditional dry method has a lower yield and contains undesirable flavor. Compared with other examples, sucrose in Example 1 plays a role in increasing the yield of resistant dextrin.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing resistant dextrin, characterized in that, Includes the following steps: (a) Sucrose and an inorganic acid are added to the starch slurry for acid hydrolysis to obtain a hydrolysate. The mass of the sucrose is 5% to 10% of the dry weight of the starch used in the preparation of the starch slurry. The inorganic acid is an inorganic acid solution. The inorganic acid solution is added at a total mass of 5% to 10% of the dry weight of the solute, based on the dry weight of the starch used in the preparation of the starch slurry. The inorganic acid includes one or more of hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid. The acid hydrolysis time is 4 to 8 hours. (b) Add medium-temperature amylase and glucoamylase to the hydrolysate for enzymatic hydrolysis to obtain the hydrolysate; (c) Adding an organic acid to the enzymatic hydrolysate to carry out a polymerization reaction, yielding crude resistant dextrin; and (d) Purify the crude resistant dextrin.

2. The method for preparing resistant dextrin according to claim 1, characterized in that, The starch milk includes one or more of corn starch milk, potato starch milk, and cassava starch milk.

3. The method for preparing resistant dextrin according to claim 1, characterized in that, The concentration of the starch milk is 30% to 40%.

4. The method for preparing resistant dextrin according to claim 1, characterized in that, Based on the dry weight of the starch used in preparing the starch milk, the amount of medium-temperature amylase added is 0.01% to 0.10% of the dry weight, and the amount of glucoamylase added is 0.02% to 0.15% of the dry weight.

5. The method for preparing resistant dextrin according to claim 1, characterized in that, The enzymatic hydrolysis satisfies at least one of the following characteristics (1) to (3): (1) The enzymatic hydrolysis temperature is 50℃~65℃; (2) The enzymatic hydrolysis time is 2 to 4 hours; (3) The pH of the enzymatic hydrolysis is 5-6.

6. The method for preparing resistant dextrin according to claim 1, characterized in that, Based on the dry weight of the starch used in preparing the starch milk, the mass of the organic acid is 1% to 5% of the dry weight.

7. The method for preparing resistant dextrin according to any one of claims 1 to 6, characterized in that, The polymerization reaction satisfies at least one of the following characteristics (4) to (6): (4) The polymerization reaction temperature is 110℃~130℃; (5) The polymerization reaction takes 2 to 5 hours; (6) The polymerization reaction is carried out under negative pressure, and the negative pressure is 0.085MPa ~ 0.10MPa.

8. The method for preparing resistant dextrin according to any one of claims 1 to 6, characterized in that, The organic acids include one or more of citric acid, malic acid, tartaric acid, and oxalic acid.

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