Buckwheat noodles and preparation method thereof

Abstract

The invention relates to the technical field of buckwheat noodles, in particular to buckwheat noodles and a preparation method thereof, and the preparation method comprises the following steps: S1, raw material pretreatment; s2, preparing powder; s3, kneading dough; s4, controllable enzymatic conversion curing; s5, step-by-step calendaring molding; s6, performing segmented low-temperature drying; and S7, cutting and packaging. No flour, salt or food additives need to be added, through whole-process technology optimization, industrial stable production of the pure sweet buckwheat noodles is achieved, and the technical blank of preparation of the pure sweet buckwheat additive-free noodles is filled up; meanwhile, through a controllable enzymatic conversion process, the proportion of rutin to quercetin is regulated and controlled under the condition that exogenous components are not added, the nutritional value of the product is improved, and the scheme is different from the scheme that flavone components are regulated and controlled by depending on exogenous addition in the prior art.

Description

Technical Field

[0001] This invention relates to the field of buckwheat noodle technology, specifically to a buckwheat noodle and its preparation method. Background Technology

[0002] Sweet buckwheat is a medicinal and edible grain crop rich in rutin, dietary fiber, minerals, and various amino acids. Its products combine nutritional value and health benefits, and have broad application prospects in the healthy staple food market. As an important category of staple food, noodles are increasingly valued for their naturalness and nutritional content. Pure sweet buckwheat noodles stand out for their additive-free and highly nutritious characteristics.

[0003] In existing technologies, such as the buckwheat noodles rich in rutin and quercetin and their preparation method disclosed in CN109965205B, the method involves mixing buckwheat sprout powder, buckwheat seed powder, and wheat flour, adding salt, and utilizing the rutin enzyme in the buckwheat seed powder to convert the rutin in the buckwheat sprout powder into quercetin. This method requires the addition of wheat flour and salt, making it impossible to achieve an additive-free buckwheat product. Furthermore, the exogenous added ingredients dilute the original nutrients of buckwheat. In addition, the existing pure sweet buckwheat noodle preparation technology still has the following problems: (1) Sweet buckwheat flour has a low protein content and contains no gluten protein at all. Gluten protein is the key component that gives noodle dough its viscoelasticity, ensures noodle shaping and resistance to boiling. If pure sweet buckwheat flour is used directly to make noodles in the existing technology, the dough is loose and has no binding force. It is very easy to break during the rolling process and cannot form a continuous noodle shape. When cooking, the noodles easily absorb water and expand, becoming sticky and clumping together in the soup, which seriously affects the taste and product quality.

[0004] (2) In order to solve the above-mentioned problems of shaping and cooking resistance, the existing buckwheat noodle production process generally adopts the method of adding exogenous ingredients, mainly including two types: one is to add wheat flour, corn flour, glutinous rice flour and other grain flours containing gluten or sticky starch. This kind of addition will dilute the proportion of sweet buckwheat flour, reduce the purity of the product, and weaken the original nutritional advantages of sweet buckwheat; the other is to add food additives such as edible gums, gluten enhancers, emulsifiers and so on. Although they can improve the physical properties of noodles, they do not meet the consumer demand for "natural and additive-free" healthy staple food, and some sensitive people still have concerns about eating them.

[0005] (3) The core nutrients in sweet buckwheat, such as rutin and vitamins, are quite sensitive to temperature. In the current process of preparing sweet buckwheat noodles, high-temperature processes are often used in the dehulling, grinding, and drying stages. High-temperature environments can cause rutin and other components to oxidize and decompose, which can significantly reduce the nutritional value of the product. At the same time, the sweet buckwheat flour produced by traditional grinding processes is not fine enough and has a weak ability to hydrate and bind the flour particles, which further exacerbates the problem of difficulty in forming noodles. Summary of the Invention

[0006] The purpose of this invention is to provide buckwheat noodles and a method for preparing the same, in order to solve the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains free from mold, and add 0-5% buckwheat sprout powder. Use a low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, and condition them for 30-40 minutes under conditions of 60%-65% humidity and 35℃-40℃ to make the moisture content of the buckwheat grains reach 13%-14% and activate the rutinase in the buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled 2-3 times, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.45-0.55. First, mix at low speed for 1-2 minutes, then mix at high speed for 8-10 minutes. Step S4, Controlled Enzymatic Conversion and Maturation: Static maturation of the dough at 25℃-28℃ and 70%-75% humidity for 30-40 minutes allows the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually reducing the gap between the calendering rollers from 5mm to 1mm at a low speed, and then cutting the dough into noodles with a thickness of 1.0mm-1.2mm or a thickness of 1.0mm and a width of 2.0mm-2.5mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 35℃-40℃, humidity 50%-55%, wind speed 1.0m / s-1.2m / s, drying time 60-80min; Second drying stage: temperature 30℃-32℃, humidity 45%-50%, wind speed 0.6m / s-0.8m / s, drying time 120-150min; The third drying stage: temperature 28℃-30℃, humidity 40%-45%, dry until the noodles have a moisture content of 10%-11%, while inactivating enzyme activity and stopping rutin conversion; Step S7, Cutting and Packaging: Cut the dried noodles into 15-40cm segments and package them to obtain the finished product.

[0008] Furthermore, the three-stage low-temperature grinding process in step S2 specifically includes: First-stage coarse grinding: A toothed roller mill is used for coarse grinding. The gap between the toothed rollers is adjusted to 2-3mm, the rotation speed is 200-300r / min, and the feeding speed is 100-150kg / h. The buckwheat rice is crushed into coarse powder with a particle size of about 500-800μm, which initially refines the material and removes some of the bran. Second-stage fine grinding: The coarse powder after coarse grinding is fed into a hammer mill for fine grinding. The screen aperture is 40-60 mesh, and the rotation speed is 800-1000 r / min. The material is refined into fine powder with a particle size of about 150-300μm. The material that does not pass through the screen is returned to the grinding mill. The third stage of grinding: The finely ground powder is fed into an air-jet mill for ultra-fine grinding. The grinding pressure is 0.6-0.8MPa and the feeding speed is 50-80kg / h. The material is refined into ultra-fine powder with a particle size of 60-120μm. Finally, it is passed through a 120-mesh sieve to obtain buckwheat flour that meets the requirements. The entire process is carried out at low temperature to preserve enzyme activity.

[0009] Furthermore, in step S3, the low-speed stirring speed is 30-50 r / min, and the high-speed stirring speed is 100-120 r / min, to enhance the binding force between buckwheat flour particles and water molecules.

[0010] Furthermore, in step S5, during the rolling process, the gap reduction of each rolling stage is 0.5-1.0 mm, and the rolling speed is 1-2 m / min.

[0011] Furthermore, the buckwheat sprout powder in step S1 is sweet buckwheat sprout powder.

[0012] The present invention also provides buckwheat noodles prepared using the buckwheat noodle preparation method described in any of the above claims.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention eliminates the need for any flour, salt, or food additives. Through optimized processes, it achieves stable industrial production of pure sweet buckwheat noodles, filling a technological gap in the preparation of additive-free pure sweet buckwheat noodles. Furthermore, by employing a controllable enzymatic conversion process, the ratio of rutin and quercetin can be adjusted without the addition of exogenous components, thereby enhancing the nutritional value of the product. This differs from existing technologies that rely on exogenous additions to regulate flavonoid components.

[0014] This invention preserves the heat-sensitive nutrients in buckwheat through a low-temperature process, while controlling the ratio of rutin and quercetin, giving the product both antioxidant and blood sugar-lowering effects, resulting in superior nutritional value.

[0015] The step-by-step calendering process and segmented low-temperature drying process of this invention improve the formability and cooking resistance of pure buckwheat noodles, reduce the breakage rate and cooking loss rate, and enhance the taste and quality of the noodles. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown, a method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains free from mold, and add 0-5% buckwheat sprout powder. Use a low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, and condition them for 30-40 minutes under conditions of 60%-65% humidity and 35℃-40℃ to make the moisture content of the buckwheat grains reach 13%-14% and activate the rutinase in the buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled 2-3 times, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, preserving enzyme activity. The three-stage low-temperature grinding process is as follows: First-stage coarse grinding: A toothed roller mill is used for coarse grinding. The gap between the toothed rollers is adjusted to 2-3mm, the rotation speed is 200-300r / min, and the feeding speed is 100-150kg / h. The buckwheat rice is crushed into coarse powder with a particle size of about 500-800μm, which initially refines the material and removes some of the bran. Second-stage fine grinding: The coarse powder after coarse grinding is fed into a hammer mill for fine grinding. The screen aperture is 40-60 mesh, and the rotation speed is 800-1000 r / min. The material is refined into fine powder with a particle size of about 150-300μm. The material that does not pass through the screen is returned to the grinding mill. The third stage of grinding: The finely ground powder is fed into an air-jet mill for ultra-fine grinding. The grinding pressure is 0.6-0.8MPa and the feeding speed is 50-80kg / h. The material is refined into ultra-fine powder with a particle size of 60-120μm. Finally, it is passed through a 120-mesh sieve to obtain buckwheat flour that meets the requirements. The entire process is carried out at low temperature to preserve enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.45-0.55. First, mix at a low speed of 30-50 r / min for 1-2 minutes, then mix at a high speed of 100-120 r / min for 8-10 minutes. Step S4, Controlled Enzymatic Conversion and Maturation: Static maturation of the dough at 25℃-28℃ and 70%-75% humidity for 30-40 minutes allows the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually reducing the gap between the calendering rollers from 5mm to 1mm at a low speed, and then cutting the dough into noodles with a thickness of 1.0mm-1.2mm or a thickness of 1.0mm and a width of 2.0mm-2.5mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 35℃-40℃, humidity 50%-55%, wind speed 1.0m / s-1.2m / s, drying time 60-80min; Second drying stage: temperature 30℃-32℃, humidity 45%-50%, wind speed 0.6m / s-0.8m / s, drying time 120-150min; The third drying stage: temperature 28℃-30℃, humidity 40%-45%, dry until the noodles have a moisture content of 10%-11%, while inactivating enzyme activity and stopping rutin conversion; Step S7, Cutting and Packaging: Cut the dried noodles into 15-40cm segments and package them to obtain the finished product.

[0019] The present invention also provides buckwheat noodles prepared using the buckwheat noodle preparation method described above.

[0020] Experimental methods for determining the content of rutin and quercetin (1) Preparation of reference standard Dissolve 0.00826 g of rutin and 0.00602 g of quercetin in separate 10 mL amber volumetric flasks, add methanol to dissolve and dilute to 10 mL to prepare reference stock solutions. Take appropriate amounts of each reference stock solution and place them in separate 10 mL amber volumetric flasks, add methanol to dilute to 10 mL to prepare a mixed standard stock solution containing 41.80 μg / mL rutin and 60.20 μg / mL quercetin. Store at 4 °C for later use.

[0021] (11) Extraction of flavonoid components from the sample Accurately weigh 0.100 g of sample into a 100 mL Erlenmeyer flask, add 30 mL of 70% methanol aqueous solution, shake well and weigh, sonicate at 60 °C for 30 min, remove and cool to room temperature, make up the mass with 70% methanol aqueous solution, shake well, centrifuge at 12000 r / min for 15 min, take the supernatant, filter through a 0.22 μm microporous membrane, and take the filtrate for analysis.

[0022] (12) Chromatographic conditions for flavonoid determination BEHC18 (2.1 mm × 50 mm, 1.7 μm) column; mobile phase: methanol (A) - 0.2% glacial acetic acid aqueous solution (B); gradient elution: 0–3 min, 10%–26% A; 3–5 min, 26%–29% A; 5–9.5 min, 29%–38% A; 9.5–13 min, 38%–44% A; 13–15 min, 44% A; 15–17 min, 44%–10% A; detection wavelength: 254 nm; column temperature: 35 °C; flow rate: 0.2 mL / min; injection volume: 1 μL.

[0023] (2) Experiment on the determination of the steaming and cooking characteristics of noodles (21) Water absorption rate determination Following the method of Matsuo et al., 20 noodles, each 20 cm long, were weighed, boiled in 500 ml of boiling water for 3 minutes, removed, cooled, and air-dried on filter paper. Their weight was then measured. Noodle water absorption rate = (weight after cooking - weight before cooking) / weight before cooking * 100% (22) Determination of cooking loss rate Collect the water used to cook the noodles, place it in an evaporating dish, heat it to a constant weight, and weigh the dry matter. Cooking loss rate = (dry matter weight / weight of cooked noodles) * 100% (23) Determination of breakage rate Take 50 noodles, boil them in boiling water for 3 minutes, then remove them and count the number of broken noodles. The breakage rate = (number of broken noodles / total number) * 100%. (3) Experiment on determination of the texture properties of noodles Select noodles of the same length and test them three times in parallel. Use a texture analyzer to measure their hardness, elasticity, and chewiness. Test parameters: speed before test is 1.0 mm / s, speed after test is 1 mm / s, compression ratio is 80%, probe is SMSP / 36R, and the pressure of the first peak of the curve represents the hardness of the noodles.

[0024] (4) Sensory evaluation experiment After cooking and cooling, the noodles were placed on a plate. Ten volunteers were selected to score the noodles according to the relevant sensory evaluation standard SB / T10137–93, and the average score was taken. The sensory evaluation standard for noodles is as follows:

[0025] Example 1 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, without adding buckwheat sprout powder, and use a low-temperature physical dehulling process. Then, condition the dehulled buckwheat rice for 30 minutes under conditions of 60% humidity and 35℃ to make the buckwheat rice moisture content reach 13% and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled twice, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, thus preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.45. First, stir at low speed for 1 minute at 30 r / min, then stir at high speed for 8 minutes at 100 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 30 minutes at 25°C and 70% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering stage is 0.5mm, the calendering speed is 1m / min, and then the dough is cut into noodles with a thickness of 1.0mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 35℃, humidity 50%, wind speed 1.0m / s, drying for 60min; Second drying stage: temperature 30℃, humidity 45%, wind speed 0.6m / s, drying for 120min; The third drying stage: at a temperature of 28℃ and a humidity of 40%, the noodles are dried until the moisture content is 10%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 15cm segments and package them to obtain the finished product.

[0026] Example 2 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 2% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 35 minutes under conditions of 62% humidity and 37℃, so that the moisture content of the buckwheat grains reaches 13.5%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled twice, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, thus preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.5. First, mix at low speed for 1.5 minutes at a speed of 40 r / min, then mix at high speed for 9 minutes at a speed of 110 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 35 minutes at 26℃ and 72% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 0.7mm, and the calendering speed is 1.5m / min. The resulting noodles are then cut into noodles that are 1.0mm thick and 2.0mm wide. Step S6: Segmented low-temperature drying: First drying stage: temperature 37℃, humidity 52%, wind speed 1.1m / s, drying time 70min; Second drying stage: temperature 31℃, humidity 47%, wind speed 0.7m / s, drying time 135min; The third drying stage: temperature 29℃, humidity 42%, dry until the noodles have a moisture content of 10.5%, while simultaneously inactivating enzyme activity and stopping rutin conversion; Step S7, Cutting and Packaging: Cut the dried noodles into 25cm segments and package them to obtain the finished product.

[0027] Example 3 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 3% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 40 minutes under conditions of 65% humidity and 40℃, so that the moisture content of the buckwheat grains reaches 14%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled three times, it is ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, retaining enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.55. First, mix at low speed for 2 minutes at 50 r / min, then mix at high speed for 10 minutes at 120 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 40 minutes at 28℃ and 75% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 1.0mm, the calendering speed is 2m / min, and then the dough is cut into noodles with a thickness of 1.0mm and a width of 2.5mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 40℃, humidity 55%, wind speed 1.2m / s, drying time 80min; Second drying stage: temperature 32℃, humidity 50%, wind speed 0.8m / s, drying for 150min; The third drying stage: at a temperature of 30℃ and a humidity of 45%, the noodles are dried until the moisture content is 11%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 40cm segments and package them to obtain the finished product.

[0028] Example 4 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 1% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 32 minutes under conditions of 61% humidity and 36℃, so that the moisture content of the buckwheat grains reaches 13.2%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled twice, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, thus preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.47. First, mix at low speed for 1.2 minutes at a speed of 35 r / min, then mix at high speed for 8.5 minutes at a speed of 105 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 32 minutes at 26℃ and 71% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 0.6mm, the calendering speed is 1.2m / min, and then the dough is cut into noodles with a thickness of 1.1mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 36℃, humidity 51%, wind speed 1.05m / s, drying time 65min; Second drying stage: temperature 30℃, humidity 46%, wind speed 0.65m / s, drying for 125min; The third drying stage: at a temperature of 28℃ and a humidity of 41%, the noodles are dried until the moisture content is 10.2%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 20cm segments and package them to obtain the finished product.

[0029] Example 5 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 4% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 38 minutes under conditions of 64% humidity and 39℃, so that the moisture content of the buckwheat grains reaches 13.8%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled three times, it is ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, retaining enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.53. First, mix at low speed for 1.8 minutes at a speed of 45 r / min, then mix at high speed for 9.5 minutes at a speed of 115 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 38 minutes at 27°C and 74% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 0.9mm, and the calendering speed is 1.8m / min. The resulting noodles are then cut into noodles that are 1.0mm thick and 2.3mm wide. Step S6: Segmented low-temperature drying: First drying stage: temperature 39℃, humidity 54%, wind speed 1.15m / s, drying time 75min; Second drying stage: temperature 31℃, humidity 49%, wind speed 0.75m / s, drying time 145min; The third drying stage: at a temperature of 29℃ and a humidity of 44%, the noodles are dried until the moisture content is 10.8%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 35cm segments and package them to obtain the finished product.

[0030] Example 6 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 2.5% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 35 minutes under the conditions of 63% humidity and 38℃, so that the moisture content of buckwheat grains reaches 13.5%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled twice, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, thus preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.5. First, mix at low speed for 1.5 minutes at a speed of 40 r / min, then mix at high speed for 9 minutes at a speed of 110 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 35 minutes at 27°C and 73% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 0.75mm, the calendering speed is 1.5m / min, and then the dough is cut into noodles with a thickness of 1.2mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 38℃, humidity 53%, wind speed 1.1m / s, drying time 70min; Second drying stage: temperature 31℃, humidity 48%, wind speed 0.7m / s, drying time 135min; The third drying stage: at a temperature of 29℃ and a humidity of 43%, the noodles are dried until the moisture content is 10.5%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 30cm segments and package them to obtain the finished product.

[0031] Example 7 A method for preparing buckwheat noodles includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains without mold, add 5% sweet buckwheat sprout powder, use low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, condition for 40 minutes under conditions of 65% humidity and 40℃, so that the moisture content of the buckwheat grains reaches 14%, and activate the rutin enzyme in buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled three times, it is ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, retaining enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.55. First, mix at low speed for 2 minutes at 50 r / min, then mix at high speed for 10 minutes at 120 r / min. Step S4, Controlled Enzymatic Conversion and Maturation: The dough is statically matured for 40 minutes at 28℃ and 75% humidity to allow the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually decreasing the gap between the calendering rollers from 5mm to 1mm at a low speed. The gap reduction for each calendering step is 1.0mm, the calendering speed is 2m / min, and then the dough is cut into noodles with a thickness of 1.0mm and a width of 2.5mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 40℃, humidity 55%, wind speed 1.2m / s, drying time 80min; Second drying stage: temperature 32℃, humidity 50%, wind speed 0.8m / s, drying for 150min; The third drying stage: at a temperature of 30℃ and a humidity of 45%, the noodles are dried until the moisture content is 11%, while simultaneously inactivating enzyme activity and stopping the conversion of rutin. Step S7, Cutting and Packaging: Cut the dried noodles into 40cm segments and package them to obtain the finished product.

[0032] Comparative Example 1 Using traditional high-temperature dehulling and grinding processes, plump and mold-free buckwheat grains are selected. No buckwheat sprout powder is added. The high-temperature dehulling process is carried out at a temperature of 80℃. Then, the dehulled buckwheat grains are traditionally ground and passed through an 80-mesh sieve to obtain buckwheat flour. For dough preparation: Use buckwheat flour and drinking water in a mass ratio of 1:0.5, and stir for 10 minutes; Maturation: Static maturation of the dough at 25℃ for 30 minutes; Calendering: Calendering from 5mm to 1mm directly through the gap of the calendering rollers, and cutting into noodles with a thickness of 1.0mm; Drying: High-temperature drying is used at 60℃ until the noodles have a moisture content of 10%. Cutting and packaging: Cut the dried noodles into 20cm segments and package them to obtain the finished product.

[0033] Comparative Example 2 In existing technology, buckwheat noodles with added wheat flour are made by selecting plump, mold-free buckwheat grains, removing the husks, grinding them into buckwheat flour, mixing the buckwheat flour and wheat flour in a 3:7 ratio, and adding 2% salt. For dough preparation: Use a mixture of flour and drinking water in a mass ratio of 1:0.5, and stir for 10 minutes. Maturation: The dough is statically matured at 25℃ for 30 minutes; Rolling and shaping: The dough is cut into noodles with a thickness of 1.0 mm by gradually reducing the gap between the rolling rollers from 5 mm to 1 mm; Drying: Segmented low-temperature drying was used, the same as in Example 1; Cutting and packaging: Cut the dried noodles into 20cm segments and package them to obtain the finished product.

[0034] Comparative Example 3 The process of this invention is adopted, but the controllable enzyme conversion and ripening step is omitted, i.e., step S4. The dough after kneading is directly rolled and shaped. Other steps are the same as in Example 1.

[0035] Table 2. Comparison of Experimental Results

[0036] The experimental results above show that the buckwheat noodles prepared in the embodiments of the present invention are superior to the comparative examples in terms of rutin and quercetin content, cooking characteristics, textural properties, and sensory scores. Example 7 showed the best results because it added 5% buckwheat malt powder and used optimal process parameters, resulting in a more reasonable ratio of rutin and quercetin, the lowest cooking loss rate and breakage rate of the noodles, and the highest sensory score.

[0037] Comparative Example 1 uses a traditional high-temperature process, which results in a significant reduction in the content of rutin and quercetin, leading to excessive water absorption, high cooking loss rate and breakage rate of the noodles, and a low sensory score. Comparative Example 2 adds wheat flour, which improves the shapeability of the noodles, but dilutes the nutritional components of buckwheat, and the content of rutin and quercetin is lower than that of the embodiments of the present invention. Comparative Example 3 omits the controllable enzymatic conversion and ripening step, resulting in a low quercetin content and poor cooking characteristics and sensory score of the noodles.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing buckwheat noodles, characterized in that, Includes the following steps: Step S1, Raw material pretreatment: Select plump buckwheat grains free from mold, and add 0-5% buckwheat sprout powder. Use a low-temperature physical dehulling process, then mix the dehulled buckwheat grains with buckwheat sprout powder, and condition them for 30-40 minutes under conditions of 60%-65% humidity and 35℃-40℃ to make the moisture content of the buckwheat grains reach 13%-14% and activate the rutinase in the buckwheat. Step S2, Flour Making: After the conditioned buckwheat rice is hulled 2-3 times, it is then ground using a three-stage low-temperature milling process and passed through a 120-mesh sieve to obtain buckwheat flour, preserving enzyme activity. Step S3, Kneading the dough: Use the buckwheat flour and drinking water from step S2 in a mass ratio of 1:0.45-0.

55. First, mix at low speed for 1-2 minutes, then mix at high speed for 8-10 minutes. Step S4, Controlled Enzymatic Conversion and Maturation: Static maturation of the dough at 25℃-28℃ and 70%-75% humidity for 30-40 minutes allows the rutin enzyme in the buckwheat to react appropriately, converting some of the rutin into quercetin and regulating the ratio of rutin to quercetin in the noodles. Step S5, step-by-step calendering: Calendering is performed by gradually reducing the gap between the calendering rollers from 5mm to 1mm at a low speed, and then cutting the dough into noodles with a thickness of 1.0mm-1.2mm or a thickness of 1.0mm and a width of 2.0mm-2.5mm. Step S6: Segmented low-temperature drying: First drying stage: temperature 35℃-40℃, humidity 50%-55%, wind speed 1.0m / s-1.2m / s, drying time 60-80min; Second drying stage: temperature 30℃-32℃, humidity 45%-50%, wind speed 0.6m / s-0.8m / s, drying time 120-150min; The third drying stage: temperature 28℃-30℃, humidity 40%-45%, dry until the noodles have a moisture content of 10%-11%, while inactivating enzyme activity and stopping rutin conversion; Step S7, Cutting and Packaging: Cut the dried noodles into 15-40cm segments and package them to obtain the finished product.

2. The method for preparing buckwheat noodles according to claim 1, characterized in that, The three-stage low-temperature grinding process in step S2 is specifically as follows: First-stage coarse grinding: A toothed roller mill is used for coarse grinding. The gap between the toothed rollers is adjusted to 2-3mm, the rotation speed is 200-300r / min, and the feeding speed is 100-150kg / h. The buckwheat rice is crushed into coarse powder with a particle size of about 500-800μm, which initially refines the material and removes some of the bran. Second-stage fine grinding: The coarse powder after coarse grinding is fed into a hammer mill for fine grinding. The screen aperture is 40-60 mesh, and the rotation speed is 800-1000 r / min. The material is refined into fine powder with a particle size of about 150-300μm. The material that does not pass through the screen is returned to the grinding mill. The third stage of grinding: The finely ground powder is fed into an air-jet mill for ultra-fine grinding. The grinding pressure is 0.6-0.8MPa and the feeding speed is 50-80kg / h. The material is refined into ultra-fine powder with a particle size of 60-120μm. Finally, it is passed through a 120-mesh sieve to obtain buckwheat flour that meets the requirements. The entire process is carried out at low temperature to preserve enzyme activity.

3. The method for preparing buckwheat noodles according to claim 1, characterized in that, In step S3, the low-speed stirring speed is 30-50 r / min, and the high-speed stirring speed is 100-120 r / min, which enhances the binding force between buckwheat flour particles and water molecules.

4. The method for preparing buckwheat noodles according to claim 1, characterized in that, In step S5, during the rolling process, the gap reduction of each rolling stage is 0.5-1.0 mm, and the rolling speed is 1-2 m / min.

5. The method for preparing buckwheat noodles according to claim 1, characterized in that, In step S6, the segmented low-temperature drying stage includes a pre-drying stage that forms a dense skin on the surface of the noodles, a balanced drying stage that allows internal moisture to migrate to the surface, and a final drying stage that inactivates rutinase to prevent further conversion of rutin.

6. The method for preparing buckwheat noodles according to claim 1, characterized in that, In step S3, the low-speed stirring speed is 30-50 r / min, and the high-speed stirring speed is 100-120 r / min, which enhances the binding force between buckwheat flour particles and water molecules.

7. The method for preparing buckwheat noodles according to claim 1, characterized in that, The buckwheat sprout powder in step S1 is sweet buckwheat sprout powder.

8. The method for preparing buckwheat noodles according to claim 1, characterized in that, In step S5, during the rolling process, the gap reduction of each rolling stage is 0.5-1.0 mm, and the rolling speed is 1-2 m / min.

9. A type of buckwheat noodle, characterized in that, The buckwheat noodles are prepared using the method described in any one of claims 1-6.

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