Method for preparing quinoa resistant starch through high-pressure enzyme method and application of quinoa resistant starch

Abstract

The invention belongs to the technical field of starch processing, and provides a method for preparing chenopodium quinoa resistant starch by a high-pressure enzyme method and application thereof, and the method comprises the following steps: S1, taking a proper amount of chenopodium quinoa, fully crushing, sieving, and weighing a certain amount of chenopodium quinoa powder; s2, performing degreasing treatment on the quinoa flour by using petroleum ether, then adding 75% ethanol, and performing vibration centrifugation to remove supernate; s3, treating the chenopodium quinoa powder with a NaOH solution, centrifuging and collecting precipitates after oscillation reaction, and washing to remove yellowish-brown substances, so as to obtain a pure white chenopodium quinoa starch crude product; s4, adding water into the quinoa starch crude product, uniformly mixing, and carrying out autoclaving treatment in an autoclave; the high-pressure enzyme preparation process adopted by the invention not only improves the extraction efficiency of the resistant starch, but also is environment-friendly and pollution-free, and the quinoa resistant starch prepared by the method has a wide application prospect in foods, can improve the nutritional ingredients and taste of the foods, and is beneficial to large-scale efficient production and functional food development.

Description

Technical Field

[0001] The invention belongs to the technical field of starch processing, in particular to a method for preparing quinoa resistant starch by a high-pressure enzymatic method and application thereof. Background Art

[0002] Resistant starch (RS), as a fermentable dietary fiber, has many benefits for human health, such as improving glucose homeostasis, enhancing satiety, etc., and has a certain preventive effect on diabetes and obesity. Quinoa, as a crop with balanced nutrients, is rich in dietary fiber, vitamins and mineral elements. However, its starch contains a large amount of rapidly digestible starch (RDS), which can easily lead to a rapid increase in blood sugar and insulin levels, increasing the risk of metabolic diseases. Therefore, it is of great significance to increase the yield of resistant starch in quinoa.

[0003] At present, the methods for preparing resistant starch mainly include physical modification, chemical method and enzymatic method. The physical modification method is environmentally friendly but the efficiency and output need to be improved; the chemical modification method has high production efficiency but there is a risk of pollution; the enzyme modification method has mild and safe reaction conditions but high cost; as a result, the above methods have poor processing efficiency in preparing resistant starch, which in turn makes the preparation of resistant starch poor and unsuitable for large-scale promotion.

[0004] To this end, technicians in this field have proposed a method for preparing quinoa resistant starch by high-pressure enzymatic method and its application, aiming to optimize the extraction process, improve the extraction efficiency and resistant starch content, while maintaining environmental friendliness, which is conducive to large-scale efficient production and functional food development. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing quinoa resistant starch by a high-pressure enzymatic method and its application, so as to solve the problems in the prior art of preparing resistant starch, such as poor processing efficiency, poor effect of preparing resistant starch, and unsuitability for large-scale promotion.

[0006] A method for preparing quinoa resistant starch by high-pressure enzymatic method, comprising:

[0007] S1. Take an appropriate amount of quinoa, grind it thoroughly, sieve it and weigh a certain amount of quinoa powder;

[0008] S2. Defatting the quinoa flour with petroleum ether, and then removing the supernatant by adding 75% ethanol and centrifuging to effectively remove residual petroleum ether and other impurities;

[0009] S3, treating quinoa powder with NaOH solution, collecting the precipitate by centrifugation after shaking reaction, and removing the yellow-brown substance by washing with water to obtain a pure white quinoa starch crude product;

[0010] S4, adding water to the crude quinoa starch and mixing, performing heat treatment on the autoclave, and then standing;

[0011] S5, adjusting the pH value of the starch paste, adding pullulanase for enzymolysis, then inactivating the enzyme and refrigerating;

[0012] S6. The resistant starch of quinoa was dried and crushed, and its content was detected using an enzymatic resistant starch kit.

[0013] Preferably, in step S1, the sieving is sieving through a 100-mesh sieve, and the weighing of a certain amount of quinoa flour is weighing 40 g of quinoa flour.

[0014] Preferably, the step S2 is specifically described as follows: first, petroleum ether is added to the quinoa flour at a solid-liquid ratio of 1:6 for defatting, and then the powder is shaken on a shaker at room temperature for 30 minutes. After shaking, the powder is added to a centrifuge tube and centrifuged at 3000 r / min to remove the supernatant, and then the above operation is repeated until the supernatant is colorless and transparent; then 75% ethanol is added at a solid-liquid ratio of 1:6, and the powder is shaken on a shaker at room temperature for 30 minutes. The supernatant is discarded by centrifugation at 3000 r / min, and the precipitate is collected and placed in a fume hood to be fully dried.

[0015] Preferably, the oscillation is assisted by ultrasonic wave to improve the efficiency of removing impurities. The frequency of the ultrasonic wave assisted oscillation is 20-40 kHz and the processing time is 10-20 minutes.

[0016] Preferably, the step S3 is specifically described as follows: weigh the fully dried defatted quinoa flour, add NaOH with a pH of 9.5-10 at a ratio of 1:10, shake on a shaker at 40°C for 3h, centrifuge at 4000r / min for 10min to remove the supernatant, collect the precipitate, add distilled water at a ratio of 1:10 to wash, centrifuge at a low speed of 1000r / min to collect the white supernatant, and discard the brown-yellow liquid at the bottom; repeat the operation 1-2 times to remove the yellow-brown substance; centrifuge at 4000r / min for 10min, discard the supernatant, scrape off impurities on the surface of the precipitate to obtain pure white quinoa starch crude product, dry in an oven at 40°C, crush, and weigh.

[0017] Preferably, the step S4 is specifically described as follows: quinoa starch is added to distilled water at a ratio of 1:10, the mixture is thoroughly mixed, and the mixture is put into a high pressure sterilizer, and subjected to pressure heat treatment at 121° C. for 30 minutes to obtain starch paste, and the starch paste is allowed to stand at 4° C. overnight.

[0018] Preferably, before the high-pressure sterilization treatment, an amylase inhibitor is added for pretreatment to reduce the generation of by-products in the subsequent enzymatic hydrolysis process, and the amount of the amylase inhibitor added is 0.1%-0.5% of the weight of the quinoa starch.

[0019] Preferably, the step S5 is specifically described as follows: 0.05M HCl is used to adjust the pH of the starch paste to 4.0-5.0, 80U / mL of pullulanase is added, the mixture is reacted at 58°C in an incubator for 8h, and then heated in a boiling water bath for 10min to inactivate the enzyme; after cooling, the mixture is refrigerated at 4°C for 24h.

[0020] Preferably, in step S6, the drying process is to place the quinoa resistant starch in an oven at 45°C for drying.

[0021] A method for preparing quinoa resistant starch by a high-pressure enzymatic method and its application in food, comprising the steps of using the method for preparing quinoa resistant starch by a high-pressure enzymatic method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention effectively improves the removal efficiency of impurities in quinoa flour through ultrasonic-assisted oscillation treatment, making the starch extraction in the subsequent steps purer, thereby improving the yield and quality of resistant starch;

[0024] 2. The present invention effectively reduces the generation of by-products in the subsequent enzymatic hydrolysis process by adding an amylase inhibitor in the pretreatment step, so that the prepared resistant starch is purer and has better functional properties;

[0025] 3. The high-pressure enzymatic preparation process adopted in the present invention not only improves the extraction efficiency of resistant starch, but also is environmentally friendly and pollution-free, which is conducive to large-scale efficient production and functional food development; at the same time, the resistant starch content of the prepared red quinoa, white quinoa and black quinoa is significantly improved, which are about 212.3 mg / g, 173.4 mg / g and 196.4 mg / g, respectively, providing strong support for the development of low glycemic index (GI) functional foods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of the method for preparing quinoa resistant starch by high pressure enzymatic method;

[0027] Figure 2 It is a schematic diagram of the impurity removal effect in quinoa powder of the present invention. DETAILED DESCRIPTION

[0028] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] Embodiment: The present invention provides a method for preparing quinoa resistant starch by high pressure enzymatic method, such as Figure 1 As shown, including:

[0030] Step 1, take an appropriate amount of quinoa and grind it thoroughly, pass it through a 100-mesh sieve, and weigh 40g of quinoa powder;

[0031] Step 2: Add petroleum ether to quinoa flour at a solid-liquid ratio of 1:6 for defatting, shake on a shaker at room temperature for 30 minutes, add to a centrifuge tube and centrifuge at 3000 r / min to remove the supernatant, and repeat the above operation until the supernatant is colorless and transparent; add 75% ethanol at a solid-liquid ratio of 1:6, shake on a shaker at room temperature for 30 minutes, centrifuge at 3000 r / min to discard the supernatant, collect the precipitate and put it in a fume hood to dry thoroughly;

[0032] Step 3, weigh the fully dried defatted quinoa powder, add NaOH with pH 9.5-10 at a ratio of 1:10, shake on a shaker at 40°C for 3h, centrifuge at 4000r / min for 10min to remove the supernatant, collect the precipitate, add distilled water at a ratio of 1:10 to wash, centrifuge at 1000r / min to collect the white supernatant, and discard the brown-yellow liquid at the bottom; repeat the operation 1-2 times to remove the yellow-brown substance; centrifuge at 4000r / min for 10min, discard the supernatant, scrape off the impurities on the surface of the precipitate, obtain the pure white quinoa starch crude product, dry in an oven at 40°C, crush, and weigh;

[0033] Step 4, add distilled water to quinoa starch at a ratio of 1:10, mix well, put into an autoclave, and heat-treat at 121°C for 30 minutes to obtain starch paste, and let the starch paste stand at 4°C overnight;

[0034] Step 5, adjusting the pH of the starch paste to 4.0-5.0 with 0.05M HCl, adding 80U / mL of pullulanase, reacting in an incubator at 58°C for 8h, then heating in a boiling water bath for 10min to inactivate the enzyme; after cooling, refrigerating at 4°C for 24h;

[0035] Step 6, drying the quinoa resistant starch in an oven at 45°C, crushing it, and weighing it;

[0036] Step 7: Use an enzymatic resistant starch kit to detect the resistant starch content of quinoa.

[0037] From the above, it can be seen that the high-pressure enzymatic preparation process adopted in the present invention not only improves the extraction efficiency of resistant starch, but also is environmentally friendly and pollution-free. The quinoa resistant starch prepared by this method has broad application prospects in food, can improve the nutritional content and taste of food, and is conducive to large-scale and efficient production and development of functional foods.

[0038] Furthermore, the oscillation is assisted by ultrasonic wave to improve the efficiency of removing impurities. The frequency of the ultrasonic wave assisted oscillation is 20-40kHz, and the processing time is 10-20 minutes.

[0039] From the above, it can be seen that by adopting ultrasonic-assisted oscillation treatment with a frequency of 20-40kHz and a treatment time of 10-20 minutes, the removal efficiency of impurities in quinoa flour is effectively improved, making the starch extraction in the subsequent steps purer, thereby improving the yield and quality of resistant starch.

[0040] Furthermore, before the high-pressure sterilization treatment, an amylase inhibitor is added for pretreatment to reduce the generation of by-products in the subsequent enzymatic hydrolysis process, and the amount of the amylase inhibitor added is 0.1%-0.5% of the weight of the quinoa starch.

[0041] From the above, it can be seen that before high-pressure sterilization, amylase inhibitor is added for pretreatment, and the added amount is 0.1%-0.5% of the weight of quinoa starch to reduce the generation of by-products in the subsequent enzymatic hydrolysis process, thereby making the prepared resistant starch purer and having better functional properties.

[0042] Furthermore, after the quinoa flour is defatted with petroleum ether, 75% ethanol is added at a solid-liquid ratio of 1:6, and the mixture is shaken on a shaker at room temperature for 30 minutes and then centrifuged at 3000 r / min. This can effectively remove the residual petroleum ether and remove alcohol-soluble proteins and other impurities that are easily soluble in ethanol from the quinoa flour, such as Figure 2 As shown (the supernatant floating matter is impurities), Figure 2 It can be seen that the efficiency of subsequent removal of upper brown impurities in the precipitate is greatly improved.

[0043] Furthermore, the petroleum ether can be recovered after use and recycled after rotary evaporation.

[0044] Furthermore, the resistant starch of red quinoa prepared by high-pressure enzymatic method was tested, and the results showed that the content of resistant starch of red quinoa prepared by high-pressure enzymatic method was about 212.3 mg / g, that of white quinoa was about 173.4 mg / g, and that of black quinoa was about 196.4 mg / g.

[0045] In summary, the high-pressure enzymatic method for preparing quinoa resistant starch improves the yield and quality of resistant starch through innovative means such as ultrasonic-assisted vibration and amylase inhibitor pretreatment, and significantly increases the content of resistant starch in quinoa, providing strong support for the development of functional foods; this method is environmentally friendly, pollution-free, and conducive to large-scale and efficient production.

[0046] Comparative Example 1: Physical modification method: Physical modification method refers to the use of heat, force, light, electricity and other means to change the original shape, structure and properties of starch particles; physical modification methods of starch include hydrothermal treatment, microwave treatment, ionizing radiation treatment, ultrasonic treatment, ball milling treatment and extrusion treatment; the following are the operating steps of the hydrothermal treatment method of common physical modification method:

[0047] ①Wet heat treatment: The process of heat treatment of starch at low moisture content, with a moisture content of less than 35% and a high temperature, generally 80-160°C;

[0048] ②Toughening treatment: a heat treatment process in which the starch water content is greater than 40% and the temperature is set below the starch gelatinization temperature;

[0049] ③ Autoclave treatment: The starch water content is greater than 40%, and the solution is treated under a certain temperature and pressure;

[0050] ④Decompression treatment: large quantities can be processed in a short time, there is no gelatinized starch granules, the thermal stability is high, and industrial production has great potential;

[0051] ⑤ Ultra-high pressure treatment: Through high pressure treatment, the double helix structure of type A crystals re-aggregates under the action of pressure, and part of it is converted into type B crystals. However, this treatment cannot lead to a decrease in molecular weight. This treatment gelatinizes the starch granules, but maintains their granular structure and does not dissolve.

[0052] Comparative Example 2: Chemical method: including chemical oxidation treatment:

[0053] The hydroxyl group in the glucose unit of starch is first oxidized to a carbonyl group and then further oxidized to a carboxyl group. The increased carbonyl and carboxylic acid have a steric effect on digestive enzymes, thereby increasing the content of resistant starch. Through experiments, it was found that after black bean starch was treated with ozone, the content of resistant starch increased from 36.2% to 44.7%.

[0054] Comparative Example 3: Enzymatic debranching: The enzymes used in enzymatic debranching are mainly debranching enzymes, the most commonly used of which is pullulanase, which is a type of isoamylase. It can hydrolyze the α-l,6 glycosidic bonds in straight-chain and branched starch molecules, and the two ends of the cut α-l,6 glycosidic bonds contain at least two or more α-l,4 glycosidic bonds, so that the hydrolyzate of starch contains more free straight-chain molecules. During the aging process of starch, more straight-chain starch double helices associate with each other to form a highly resistant crystal structure.

[0055] The effects of the technical solutions of the embodiment and comparative examples 1 to 3 are compared to obtain the following table:

[0056]

[0057]

[0058] It can be seen from the above table that: (1) the high-pressure enzyme method used in the embodiment combines the advantages of high pressure and enzymatic hydrolysis, and has a high treatment efficiency; some methods in the physical modification method (such as autoclave treatment and ultra-high pressure treatment) are also highly efficient, but overall, the treatment efficiency of the physical modification method varies from method to method and is relatively low; the chemical method generally has a high treatment efficiency, but is accompanied by environmental pollution; the enzymatic method has a medium treatment efficiency, which mainly depends on the rate of the enzymatic hydrolysis reaction;

[0059] (2) The high-pressure enzymatic method of the embodiment significantly increases the yield of resistant starch by optimizing the extraction process; although the physical modification method and the chemical method can also increase the yield of resistant starch, the effect is not as significant as the high-pressure enzymatic method; although the enzymatic method can prepare high-purity resistant starch, the yield is limited by the efficiency of the enzymatic reaction and the availability of the substrate;

[0060] (3) The resistant starch prepared by the high-pressure enzymatic method of the embodiment is of excellent quality because the method effectively removes impurities and reduces the generation of by-products; the chemical method is prone to chemical residues, which affects the quality of the resistant starch; the resistant starch prepared by the physical modification method and the enzymatic method has medium to excellent quality, depending on the specific processing conditions and parameters;

[0061] (4) The high-pressure enzyme method in the embodiment is environmentally friendly, pollution-free, and meets the requirements of sustainable development; some methods in the physical modification method (such as reduced pressure treatment and ultra-high pressure treatment) are also highly environmentally friendly, but overall, the environmental friendliness of the physical modification method varies from method to method; the chemical method has pollution risks and is not environmentally friendly; the enzyme method is a relatively environmentally friendly treatment method;

[0062] (5) The high-pressure enzymatic method of the embodiment is conducive to large-scale and efficient production because it has high processing efficiency, is environmentally friendly, and produces resistant starch with high yield and quality. Although physical modification and chemical methods can also be used for large-scale production, they are easily limited by factors such as processing efficiency, environmental pollution, and cost. The enzymatic method is limited by the rate of the enzymatic reaction and the availability of the substrate, and has medium to high potential for large-scale production.

[0063] Test example: Application of quinoa resistant starch prepared by a method for preparing quinoa resistant starch by high pressure enzymatic method in food, the operation steps of which include:

[0064] 1) Preparation of quinoa resistant starch:

[0065] First, quinoa resistant starch is prepared according to the method in the given invention content; this includes the steps of quinoa crushing, screening, defatting, NaOH solution treatment, water washing to remove yellow-brown substances, high-pressure sterilization pot pressure heat treatment, pH value adjustment, pullulanase enzymolysis reaction, enzyme inactivation treatment, refrigeration, drying and crushing, and finally obtaining quinoa resistant starch;

[0066] 2) Food application test design:

[0067] Choose appropriate foods as test subjects, such as bread, biscuits, noodles, etc.;

[0068] Design different amounts of quinoa resistant starch to explore its effects on food taste, texture and nutritional value;

[0069] Prepare the raw materials and tools required for the test and ensure the cleanliness and hygiene of the test environment;

[0070] 3) Food preparation:

[0071] Adding the prepared quinoa resistant starch into food raw materials according to a designed addition amount;

[0072] Prepare according to conventional food production processes, including steps such as mixing, shaping, baking or cooking;

[0073] During the production process, pay attention to observe and record changes in food, such as color, smell, taste, etc.;

[0074] 4) Food quality assessment:

[0075] Conduct quality assessment of prepared foods, including taste testing, texture analysis, nutritional content testing, etc.;

[0076] A certain number of consumers can be invited to taste and rate the food to obtain a more objective evaluation of food quality;

[0077] According to the evaluation results, adjust the amount of quinoa resistant starch added and the production process to optimize the taste and nutritional value of the food;

[0078] 5) Data analysis and conclusion:

[0079] Conduct statistical analysis on the test data and compare the quality differences of food with different addition amounts;

[0080] The conclusions were drawn to clarify the optimal amount of quinoa resistant starch added to food and its effect on food quality;

[0081] 6) Application promotion:

[0082] Based on the test results, quinoa resistant starch will be applied to actual food production and promoted to the market;

[0083] During the promotion process, focus on product publicity and marketing to increase consumers' awareness and acceptance of quinoa resistant starch and its foods.

[0084] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for preparing quinoa resistant starch by high pressure enzymatic method, characterized in that: include: S1. Take an appropriate amount of quinoa, grind it thoroughly, sieve it and weigh a certain amount of quinoa powder; S2, defatting the quinoa flour with petroleum ether, and then removing the supernatant by adding 75% ethanol and centrifuging; S3, treating quinoa powder with NaOH solution, collecting the precipitate by centrifugation after shaking reaction, and removing the yellow-brown substance by washing with water to obtain a pure white quinoa starch crude product; S4, adding water to the crude quinoa starch and mixing, performing heat treatment on the autoclave, and then standing; S5, adjusting the pH value of the starch paste, adding pullulanase for enzymolysis, then inactivating the enzyme and refrigerating; S6. The resistant starch of quinoa was dried and crushed, and its content was detected using an enzymatic resistant starch kit.

2. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: In step S1, the sieving is sieving through a 100-mesh sieve, and the weighing of a certain amount of quinoa flour is weighing 40 g of quinoa flour.

3. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: The specific description of step S2 is as follows: first, petroleum ether is added to quinoa powder at a solid-liquid ratio of 1:6 for defatting, and then the powder is shaken on a shaker at room temperature for 30 minutes. After shaking, the powder is added to a centrifuge tube and centrifuged at 3000 r / min to remove the supernatant, and then the above operation is repeated until the supernatant is colorless and transparent; then 75% ethanol is added at a solid-liquid ratio of 1:6, and the powder is shaken on a shaker at room temperature for 30 minutes. The powder is centrifuged at 3000 r / min to discard the supernatant, and the precipitate is collected and placed in a fume hood to be fully dried.

4. The method for preparing quinoa resistant starch by high pressure enzymatic method as claimed in claim 3, characterized in that: The shaking is performed by ultrasonic-assisted shaking, the frequency of the ultrasonic-assisted shaking is 20-40 kHz, and the processing time is 10-20 minutes.

5. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: The specific description of step S3 is as follows: weigh the fully dried defatted quinoa powder, add NaOH with a pH of 9.5-10 at a ratio of 1:10, shake on a shaker at 40°C for 3h, centrifuge at 4000r / min for 10min to remove the supernatant, collect the precipitate, add distilled water at a ratio of 1:10 to wash, centrifuge at a low speed of 1000r / min to collect the white supernatant, and discard the brown-yellow liquid at the bottom; repeat the operation 1-2 times to remove the yellow-brown substance; centrifuge at 4000r / min for 10min, discard the supernatant, scrape off impurities on the surface of the precipitate to obtain pure white quinoa starch crude product, dry in an oven at 40°C, crush, and weigh.

6. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: The specific description of step S4 is as follows: quinoa starch is added to distilled water at a ratio of 1:10, the mixture is thoroughly mixed, and the mixture is put into a high pressure sterilizer and subjected to pressure heat treatment at 121° C. for 30 minutes to obtain starch paste, which is then allowed to stand at 4° C. overnight.

7. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 6, characterized in that: Before the high-pressure sterilization treatment, an amylase inhibitor is added for pretreatment, wherein the amount of the amylase inhibitor added is 0.1%-0.5% of the weight of the quinoa starch.

8. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: The step S5 is specifically described as follows: 0.05M HCl is used to adjust the pH of the starch paste to 4.0-5.0, 80U / mL of pullulanase is added, the mixture is reacted at 58°C for 8h in an incubator, and then heated in a boiling water bath for 10min to inactivate the enzyme; after cooling, the mixture is refrigerated at 4°C for 24h.

9. The method for preparing quinoa resistant starch by high pressure enzymatic method according to claim 1, characterized in that: In step S6, the drying process is to place the quinoa resistant starch in an oven at 45°C for drying.

10. Application of quinoa resistant starch prepared by a method for preparing quinoa resistant starch by a high-pressure enzymatic method in food, characterized in that: The steps of preparing quinoa resistant starch using a high pressure enzymatic method as described in any one of claims 1-9.

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