Buckwheat flour and preparation method thereof

Abstract

The present invention provides buckwheat flour and a preparation method thereof. The buckwheat flour of the present invention has a specific water-soluble content, a ΔCP value of 1500 to 2600 mPa·s, and a V95 value of 160 or less. Furthermore, the present invention provides a method for grading buckwheat flour based on three indicators: water-soluble content, white brightness (L / (a+b)), and total protein content, thereby enabling convenient and stable production of the buckwheat flour of the present invention. The buckwheat flour of the present invention can be used to produce paste-type buckwheat foods with excellent slurry stability before steaming, a moderate gel texture after steaming, and low sedimentation and water precipitation.

Description

Technical Field

[0001] The invention belongs to the field of food processing, in particular to the field of preparation or processing of high-quality buckwheat flour. Background Art

[0002] Buckwheat, a dicotyledonous plant belonging to the Polygonaceae family and the genus Fagoprum, has attracted increasing consumer interest in recent years due to its unique nutritional composition and benefits.

[0003] Buckwheat is rich in nutrients. Analysis shows that its seeds contain 7.94% to 17.15% protein, 2.00% to 3.64% fat, 67.45% to 79.15% starch, and 1.04% to 1.33% cellulose. Japanese researchers report that buckwheat's nutritional value index is 80 to 92, compared to 70 for wheat and 50 for rice. Buckwheat protein is also rich in lysine, and contains more trace elements such as iron, manganese, and zinc than other grains. It also contains dietary fiber, 10 times more than refined rice. Therefore, buckwheat has excellent nutritional and health benefits. For example, buckwheat is rich in vitamin E and soluble dietary fiber, as well as niacin and rutin (rutin). Studies have also shown that buckwheat can lower blood cholesterol, prevent breast cancer caused by 7,12-dimethylanthracene, inhibit gallstone formation, and has anti-aging effects. The International Grains Council (ICC) calls buckwheat a new and promising functional food ingredient.

[0004] Reference 1 discloses a method for preparing buckwheat noodles, which involves selecting buckwheat, removing the bitter buckwheat husks, and then grinding the husks into rice cores. The rice cores are then ground and screened to obtain flour for use in making noodles. Reference 2 discloses a method for preparing fully nutritious buckwheat rice, which is obtained by hulling, milling, polishing, and grading the bitter buckwheat.

[0005] In addition, bowl balls and sausages are both specialty snacks from Northwest China. They are made by adding buckwheat flour to water, stirring it into a thin paste, and then steaming and cooling it. Reference 3 notes that buckwheat starch has a significant impact on processing characteristics and product quality during the production of buckwheat products. For example, the production of buckwheat bowl holders requires a high viscosity starch.

[0006] In addition, many scholars are currently studying the extraction methods, structural characteristics, physical and chemical properties, and nutritional functionality of buckwheat starch, buckwheat protein, and buckwheat polysaccharides. For example, Reference 4 and Reference 5 conducted graded preparation of buckwheat flour protein and measured and analyzed its physical and chemical properties.

[0007] References:

[0008] Reference 1: CN101940279B

[0009] Reference 2: CN103704578B

[0010] Reference 3: “Effects of different storage time and temperature on the properties of buckwheat starch”, Yang Zhengge,

[0011] Journal of the Chinese Cereals and Oils Association, Vol. 35, No. 2, 2020.

[0012] Reference 4: “Study on the physical and chemical properties and modification of buckwheat starch”, Zhang Guoquan, Northwest Agriculture and Forestry University, PhD thesis, 2007.

[0013] References: 5: “Graded Preparation and Physicochemical Properties of Tartary Buckwheat Flour Protein”, Guo Xiaona et al.

[0014] Journal of Food and Biotechnology, Vol. 25, No. 3, 2005. Summary of the Invention

[0015] Problems to be solved by the invention

[0016] In the past, when using buckwheat to prepare thin paste foods, this type of buckwheat food was mainly made by traditional manual crafts. With the gradual improvement of industrialization level, higher requirements are also placed on the quality stability of industrial products.

[0017] However, due to the diversity of buckwheat varieties and production areas in the current market, mixed planting and mixed harvesting are very common, making it difficult to purchase a single pure buckwheat variety. In addition, the differences in buckwheat flour processing technology lead to large differences in the quality of commercially purchased buckwheat flour when used to process bowl balls and sausage products. Common problems include severe slurry stratification before steaming, or sedimentation and water precipitation in the middle of the bowl after steaming, or the product being too soft or hard and brittle, affecting operation and sensory perception.

[0018] While references such as References 1 and 2 propose raw material grading, these methods are limited to physical screening, polishing, and other grading methods. Further practice has revealed that even with these methods, the quality of the processed buckwheat paste is still significantly affected by the raw material's characteristics. This is because, despite the physical grading of buckwheat grains, these methods cannot address the fluctuations and unevenness in the nutritional composition of buckwheat from different origins. Furthermore, while references such as References 4 and 5 propose grading theories based on nutritional composition, in practice, it remains difficult to obtain high-quality and stable buckwheat flour in a practical manner when dealing with buckwheat from diverse sources.

[0019] Therefore, it can be seen that the research on the mixed system of buckwheat flour is still not sufficient, especially the impact of the physical and chemical properties of buckwheat flour on the application performance of traditional buckwheat food has not been clearly reported.

[0020] In response to the aforementioned problems of the prior art, the present invention primarily provides buckwheat flour, which can be a processed and mixed buckwheat flour derived from various commercially available buckwheat grains. The buckwheat flour has a specific water-soluble content and viscosity characteristics. As a result, the buckwheat flour not only improves the system stability and uniformity of buckwheat flour paste products, but also avoids the deterioration of quality uniformity caused by differences in raw material quality.

[0021] Furthermore, the present invention also provides a new method for grading buckwheat flour. Specifically, the present invention proposes for the first time to grade buckwheat flour obtained from buckwheat grains from various regions based on the water-soluble matter content, brightness, and total protein content. As a result, buckwheat flour with controllable quality and a stable paste product system can be conveniently obtained by mixing buckwheat flours of different grades, which is beneficial to the uniformity of industrial product production.

[0022] Solutions for solving problems

[0023] [1] The present invention first provides a buckwheat flour, wherein the buckwheat flour has:

[0024] The content of water-soluble substances in the buckwheat flour is less than 15% by weight based on the dry weight of the buckwheat flour;

[0025] ΔCP value is 1500~2600mPa·s;

[0026] V95 value is below 160;

[0027] in:

[0028] ΔCP value means: CP measured according to standard procedure 1 in GB / T 24853-2010 95 -CP1 value, where CP 95 is the viscosity value at 95°C recorded 360 seconds after the temperature control program is started, and CP1 is the average viscosity value within the range of 50-65°C in the temperature rise stage of the temperature control program;

[0029] V95 value means: 2×STDEV(CP 320 :CP 436 ) value, where STDEV(CP 320 :CP 436 ) represents the value of the standard deviation function of the viscosity values ​​at 95°C from the 320th second to the 436th second.

[0030] [2] The buckwheat flour according to [1], wherein the content of the water-soluble substance is 1 to 13% by mass based on the dry weight of the buckwheat flour.

[0031] [3] The buckwheat flour according to [1] or [2], wherein the V95 value is 100 to 140.

[0032] [4]. Furthermore, the present invention provides a buckwheat flour, wherein the buckwheat flour comprises:

[0033] First-grade buckwheat flour, second-grade buckwheat flour, and optional third-grade buckwheat flour;

[0034] The first-grade buckwheat flour has a water-soluble matter content of 10% by mass or less, a whiteness L / (a+b) value calculated according to the CIE colorimetric of 3 or more, and a total protein content of 14% by mass or less;

[0035] The secondary buckwheat flour has a water-soluble matter content of 10% to 28% by mass, a whiteness L / (a+b) value calculated according to the CIE colorimetric of 2 or more and less than 3, and a total protein content of 14% to 30% by mass;

[0036] The third-grade buckwheat flour has a water-soluble matter content greater than 28% by mass, a whiteness L / (a+b) value calculated according to CIE chromaticity of less than 2, and a total protein content of more than 30% by mass.

[0037] Wherein, based on the total mass of the first-grade buckwheat flour and the second-grade buckwheat flour, the content of the first-grade buckwheat flour is 85% to 95% by mass; based on the total mass of the buckwheat flour, the content of the third-grade buckwheat flour is 2.5% or less by mass.

[0038] The water-soluble substance content and total protein content are based on the dry weight of buckwheat flour.

[0039] [5] The buckwheat flour according to [4], wherein the first-grade buckwheat flour has a water-soluble matter content of 1 to 10% by mass, an L / (a+b) value of 3 to 7.5, and a total protein content of 4 to 14% by mass; and the second-grade buckwheat flour has a water-soluble matter content of 11 to 25% by mass, an L / (a+b) value of 2.2 to 2.7, and a total protein content of 15% to 25% by mass.

[0040] [6] The present invention further provides a method for preparing buckwheat flour, the method comprising:

[0041] a grading step for grading buckwheat flour obtained by processing buckwheat grains according to the water-soluble matter content, the whiteness L / (a+b) value calculated according to the CIE colorimetric, and the total protein content;

[0042] a mixing step of mixing the graded buckwheat flours according to a measured ratio;

[0043] The water-soluble substance content and total protein content are based on the dry weight of buckwheat flour.

[0044] [7] The method according to [6], wherein the classification step produces first-grade buckwheat flour, second-grade buckwheat flour, and optionally third-grade buckwheat flour, wherein:

[0045] The first-grade buckwheat flour has a water-soluble matter content of 10% by mass or less, an L / (a+b) value of 3 or more, and a total protein content of 14% by mass or less;

[0046] The secondary buckwheat flour has a water-soluble matter content of 10% to 28% by mass, an L / (a+b) value of 2 or more and less than 3, and a total protein content of 14% to 30% by mass.

[0047] The third-grade buckwheat flour has a water-soluble matter content of greater than 28% by mass, an L / (a+b) value of less than 2, and a total protein content of greater than 30% by mass.

[0048] [8] The method according to [7], wherein, in the mixing step, the first-grade buckwheat flour and the second-grade buckwheat flour are mixed in a mass ratio of 85-95:15-5; and the content of the third-grade buckwheat flour is 2.5% by mass or less based on the total mass of the buckwheat flour.

[0049] [9]. Furthermore, the present invention also provides a flour, wherein the flour comprises buckwheat flour according to any one of the above [1] to [5] or buckwheat flour obtained according to any one of the above [6] to [8].

[0050]

[10] . Furthermore, the present invention also provides a food product, wherein the food product is obtained by processing the flour according to [9] above. Preferably, the food product includes bowl-shaped balls, sausages or noodles.

[0051] Effects of the Invention

[0052] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0053] The buckwheat flour according to the present invention has stable and controllable quality, and can avoid fluctuations in flour quality caused by different raw material sources.

[0054] The paste-type steamed buckwheat food prepared from the buckwheat flour according to the present invention has a stable slurry during operation and is not easy to separate; and after steaming, the gel texture is moderate, neither soft nor hard and brittle;

[0055] In some preferred embodiments, the paste-type steamed buckwheat food produced by the present invention has a uniform texture after steaming, and there is no obvious sedimentation or water separation in the center; therefore, the buckwheat flour of the paste-type steamed buckwheat food of the present invention has strong adaptability and is not only suitable for handmade bowl dumplings, sausages and other foods, but also suitable for industrial production lines to produce bowl dumplings, sausages and other foods.

[0056] In addition, the present invention provides a new basis and concept for buckwheat flour grading. According to the grading basis, buckwheat flour of different qualities can be graded and then the required buckwheat flour can be obtained by mixing buckwheat flour of different grades according to actual needs. This method can provide a stable and reliable method for preparing buckwheat flour of different qualities in a more convenient and easy to operate on an industrial scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 : Program temperature rise curve diagram in viscosity test of the present invention DETAILED DESCRIPTION

[0058] The following is a detailed description of the present invention. The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0059] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0060] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0061] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0062] In this specification, the use of "multiple" refers to a numerical value of 2 or more.

[0063] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0064] In this specification, the term "room temperature" refers to an indoor ambient temperature of 25°C.

[0065] In this specification, the unit names used are all international standard unit names, and unless otherwise stated, the "%" used means weight or mass percentage.

[0066] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0067] <First Aspect>

[0068] In a first aspect of the present invention, there is provided buckwheat flour having specific physicochemical properties, including the content of water-soluble substances based on the dry weight of the buckwheat flour and viscosity characteristics.

[0069] The buckwheat flour of the present invention is obtained by processing buckwheat to obtain buckwheat grains, and further grinding them. Furthermore, in some specific embodiments of the present invention, the buckwheat flour of the present invention can be obtained by mixing buckwheat flours obtained from multiple sources (e.g., different origins or qualities).

[0070] The present invention does not specifically limit the source of buckwheat. Shelled buckwheat grains can be obtained by subjecting commercially available buckwheat to one or more processes, including impurity removal, shelling, polishing, grading, and sterilization. In some preferred embodiments, water or heat treatment can be used at any time during the aforementioned processes to assist in shelling or shell / seed separation. In other specific embodiments of the present invention, commercially available shelled buckwheat grains can also be obtained.

[0071] The buckwheat grains from the aforementioned sources are then subjected to a flour milling process. The flour milling process is not particularly limited in the present invention, and conventional processing methods in the art may be employed. In some specific embodiments, such processing methods may include cleaning, comminution, grinding, screening, powder cleaning, and powder blending.

[0072] The buckwheat flour of the present invention can be obtained by grading one or more buckwheat flours obtained by the above process or by mixing the graded buckwheat flours according to a measured amount, so that the buckwheat flour has the physical and chemical properties described below.

[0073] Content of water-soluble substances

[0074] The buckwheat flour of the present invention has a water-soluble content of 15% by weight or less based on dry weight. The water-soluble content is derived from components such as soluble starch, cellulose, fat, or salt that can be dissolved in an aqueous solution having a certain ionic strength.

[0075] In some preferred embodiments of the present invention, the content of the water-soluble substance is no more than 13% by mass, more preferably no more than 10% by mass, and even more preferably no more than 8% by mass. Furthermore, there is no particular lower limit for the water-soluble substance content, and it may be 1% by mass or more, 2% by mass or more, or 3% by mass or more.

[0076] If the water-soluble matter content is too high, there is a concern that the system stability of the slurry may be reduced when preparing a paste-type product containing buckwheat flour.

[0077] The content of the water-soluble substance of the present invention can be obtained according to the following test method:

[0078] Buckwheat flour with a dry mass of m is weighed and added to a 2% (m / v) sodium chloride solution. The mixture is shaken in a constant temperature water bath (140 rpm, 30°C) for 30 min. After cooling to room temperature, the supernatant is collected by centrifugation and then dried at above 100°C to a constant weight (m'). Then:

[0079] Water-soluble matter content % = m' / m x 100%.

[0080] Viscosity characteristics

[0081] The viscosity characteristics of the buckwheat flour of the present invention mainly include the viscosity change of the aqueous system within a specific temperature range and the viscosity stability at a specific temperature.

[0082] More specifically, the viscosity characteristics of the present invention include a ΔCP value and a V95 value.

[0083] In some specific embodiments, the buckwheat flour of the present invention has a ΔCP value of 1500 to 2600 mPa·s; preferably, the ΔCP value of the present invention is 1700 to 2500 mPa·s; further preferably, the ΔCP value of the present invention is 1750 to 2450 mPa·s.

[0084] In some other specific embodiments, the buckwheat flour of the present invention has a V95 value of less than 160; preferably, the V95 value of the present invention is 100-140; further preferably, the V95 value of the present invention is 105-135.

[0085] The viscosity characteristics of the present invention are presumably related to the type (eg, amylose, amylopectin) and content distribution of starch in buckwheat flour.

[0086] Furthermore, the ΔCP value and V95 value of the present invention can be obtained according to the measurement method of standard procedure 1 in the standard "GB / T 24853-2010 - Determination of Gelatinization Properties of Wheat, Rye, Flours and Starches - Rapid Viscometer Method", and the corresponding viscosity values ​​can be obtained by testing using a viscosity tester such as the Botong RVA series (Botong RVA-S4) (the following viscosity values ​​are all in mPa·s or centipoise):

[0087] 1) forming an aqueous system with a buckwheat flour dry weight:water weight ratio of approximately 1:10 (see Table A.1 of the standard "GB / T 24853-2010 - Determination of Gelatinization Properties of Wheat, Rye, and Their Flours and Starch - Rapid Viscometer Method");

[0088] 2) Under the conditions of initial temperature of 50°C and stable stirring speed of 160 rpm, Figure 1 Perform temperature control using the temperature control program shown, and record the viscosity at the following time points or the average viscosity within the time period (the reading interval is 1 to 5 seconds, such as 1 second, 2 seconds, 3 seconds, 4 seconds or 5 seconds, etc., preferably 4 seconds);

[0089] 3) ΔCP value means: the viscosity value CP at 95℃ is recorded 360s after the temperature control program is started. 95 , and calculate the average viscosity value CP1 of the test system in the range of 50-65℃ in the temperature control program during the heating stage (with more than 10 value points), then, ΔCP=CP 95 -CP1

[0090] 4) V95 value indicates the stability of viscosity at a constant temperature of 95°C from 320s to 436s after the temperature control program is started. 320 :CP 436 ) is calculated. Among them, STDEV(CP 320 :CP 436 ) represents the value of the standard deviation function of the viscosity values ​​at 95° C. from the 320th second to the 436th second. The value of the standard deviation function can be calculated by referring to existing calculation methods or calculation methods provided by software.

[0091] By controlling the water-soluble substances and viscosity characteristics of the present invention, buckwheat flour can be obtained that is particularly suitable for preparing paste-based steamed foods. The buckwheat flour of the present invention improves system stability when forming a paste system, reduces sedimentation and stratification over time, and the steamed product has a moderate gel texture with minimal or no sedimentation during steaming, which promotes uniformity during the product production process.

[0092] Furthermore, by controlling the water-soluble substances and viscosity characteristics, the problem of uneven quality of buckwheat flour caused by factors such as different regions and climates can be avoided or shielded, providing a reliable guarantee for the industrial production of buckwheat flour or its products with uniform quality.

[0093] <Second Aspect>

[0094] In a second aspect of the present invention, a method for grading buckwheat or buckwheat flour is proposed for the first time, which is different from the conventional method.

[0095] As mentioned above, previous grading methods have mostly been used to grade buckwheat grains, using mechanical screening and evaluation criteria such as surface appearance. However, these grading methods are not based on the nutritional composition of buckwheat, making it difficult to overcome the uneven quality of buckwheat flour caused by regional and climatic factors. Furthermore, while existing research has explored or graded the nutritional composition of buckwheat, no specific, practical implementation method has been proposed.

[0096] The grading method of the present invention mainly grades buckwheat flour based on the content of water-soluble substances in the buckwheat flour (based on the dry weight of the buckwheat flour), the brightness L / (a+b) value calculated according to the CIE colorimeter, and the total protein content (based on the dry weight of the buckwheat flour). In the brightness L / (a+b) value calculated according to the CIE colorimeter, L represents lightness, ranging from 0 to 100, indicating color from dark (black) to light (white); a represents red and green, with values ​​varying from positive to negative, indicating color from red (positive) to green (negative), with larger a values ​​indicating redder color and smaller a values ​​indicating greener color; and b represents yellow and blue, with values ​​varying from positive to negative, indicating color from yellow (positive) to blue (negative), with larger b values ​​indicating yellower color and smaller b values ​​indicating bluer color.

[0097] In some specific embodiments of the present invention, first-grade buckwheat flour and second-grade buckwheat flour can be obtained according to the grading method of the present invention.

[0098] The first-grade buckwheat flour has a water-soluble content of less than 10% by mass, a whiteness L / (a+b) value calculated according to the CIE colorimeter of 3 or greater, and a total protein content of less than 14% by mass; the second-grade buckwheat flour has a water-soluble content of 10% to 28% by mass, a whiteness L / (a+b) value calculated according to the CIE colorimeter of 2 or greater and less than 3, and a total protein content of 14% to 30% by mass.

[0099] In some preferred embodiments of the present invention, the first-grade buckwheat flour has a water-soluble matter content of 1 to 10% by mass, more preferably 2 to 8% by mass, and even more preferably 3 to 7% by mass; the whiteness L / (a+b) value calculated according to the CIE chromaticity is 3 to 7.5, more preferably 3.3 to 7.2; and the total protein content is 4 to 14% by mass, more preferably 5 to 13% by mass.

[0100] In some preferred embodiments of the present invention, the secondary buckwheat flour has: a water-soluble matter content of 11 to 25% by mass, more preferably 11.5 to 23% by mass; a whiteness L / (a+b) value calculated according to CIE chromaticity of 2.2 to 2.7, more preferably 2.3 to 2.5; and a total protein content of 15 to 25% by mass, more preferably 18 to 23% by mass.

[0101] In some other embodiments of the present invention, the grading method of the present invention can also produce third-grade buckwheat flour. The third-grade buckwheat flour has a water-soluble matter content of greater than 28% by mass, a whiteness L / (a+b) value calculated using the CIE colorimetric of less than 2, and a total protein content of greater than 30% by mass, preferably between 30 and 40% by mass.

[0102] The present invention believes that the buckwheat flour obtained according to the above classification can be mixed according to the measured amount to obtain the buckwheat flour described in the first aspect of the present invention in a convenient and highly controllable manner.

[0103] In some specific embodiments of the present invention, the first-grade buckwheat flour can be mixed with the second-grade buckwheat flour and, optionally, the third-grade buckwheat flour. In some preferred embodiments, when the first-grade buckwheat flour and the second-grade buckwheat flour are mixed, the first-grade buckwheat flour content can be 85-95% by mass, preferably 87-92% by mass, based on the total weight of the first-grade buckwheat flour and the second-grade buckwheat flour. Furthermore, when the first-grade buckwheat flour, the second-grade buckwheat flour, and the third-grade buckwheat flour are mixed, the third-grade buckwheat flour content can be 2.5% or less by mass, preferably 2% or less by mass, based on the total weight of the buckwheat flour, to ensure the effects of the present invention.

[0104] Furthermore, based on the aforementioned grading method, the present invention also provides a method for preparing buckwheat flour, which can be considered mixed buckwheat flour. Specifically, the method comprises: a grading step in which buckwheat flour processed from buckwheat grains is graded based on water-soluble matter content, whiteness L / (a+b) value calculated using the CIE colorimeter, and total protein content; and a mixing step in which the graded buckwheat flours are mixed according to a measured ratio.

[0105] In the classification step, at least the first-grade buckwheat flour and the second-grade buckwheat flour described above are obtained, and optionally, third-grade buckwheat flour can be obtained. In the mixing step, in a specific embodiment, the first-grade buckwheat flour and the second-grade buckwheat flour are mixed in a mass ratio of 85-95 parts by mass: 15-5 parts by mass.

[0106] <Third Aspect>

[0107] A third aspect of the present invention provides flour, wherein the flour of the present invention refers to aggregates having a powdery morphology.

[0108] In some specific embodiments, the flour is buckwheat flour obtained according to the first or second aspect of the present invention and having the physicochemical properties defined in the present invention.

[0109] Such buckwheat flour may be further subjected to any other post-processing processes, which may include: adding other nutrients, auxiliary materials or food additives, pulverization, boronization, drying, disinfection, etc.

[0110] In other specific embodiments, the flour can be a mixture of buckwheat flour obtained according to the first or second aspect of the present invention and having the physical and chemical properties defined herein, and other types of flour. Examples of other types of flour include one or more of: poria powder, wheat flour, coix seed flour, yam powder, white lotus powder, kudzu root powder, konjac flour, and other plant extract powders. In some preferred embodiments, the content of buckwheat flour according to the present invention in the flour is 50% by mass or greater, more preferably 70% by mass or greater, and even more preferably 90% by mass or greater.

[0111] <Fourth Aspect>

[0112] In a fourth aspect, the present invention provides a food product based on the buckwheat flour of the present invention or based on flour comprising the buckwheat flour of the present invention.

[0113] The food products of the present invention include semi-finished food products and finished food products.

[0114] There are no particular limitations on semi-finished food products, and examples include: semi-finished water-containing dough or slurry containing the buckwheat flour of the present invention, which may be further gelatinized; dough products; and dough wrappers, such as dumpling wrappers and steamed bun wrappers.

[0115] There is no particular limitation on the finished food products, and examples thereof include: fresh wet noodles, dried noodles, instant noodles, steamed buns, nutritional powder, etc.

[0116] In addition, it has been found that the buckwheat flour of the present invention is particularly suitable for preparing paste products and can achieve improved system stability and uniformity, and can also avoid the problem of insufficient uniformity of product quality caused by differences in raw material quality.

[0117] Typical examples of such paste-based products include bowl dumplings and sausages. Furthermore, the steamed buckwheat paste-based food prepared with buckwheat flour according to the present invention has a stable slurry during operation and is not prone to separation. Furthermore, after steaming, the gel has a moderate texture, neither too soft nor too brittle.

[0118] Example

[0119] Hereinafter, the technical solution of the present invention will be described through specific embodiments.

[0120] (Test Method)

[0121] Determination of water-soluble matter content :

[0122] To 500 g of buckwheat flour (dry weight m), add 18 ml of 2% (m / v) sodium chloride solution and heat in a constant temperature (30°C) water bath with shaking (frequency 140 rpm) for 30 min. After cooling, centrifuge at 3000 rpm for 20 min. Collect the supernatant in an aluminum box (weighed m1) and dry at 105°C to a constant total weight (m2).

[0123] Then the water-soluble matter content % = (m2-m1)×100% / m.

[0124] ΔCP value and V95 determination method :

[0125] Using a Botong RVA-S4, 3g of sample (water content 14%) and 25g of deionized water were weighed in a sample bottle. The initial temperature was 50°C, and the speed was 960 rpm for rapid stirring for 10 seconds and then kept constant at 160 rpm until the end of the experiment. The heating and cooling program is shown in Table 1 and the attached Figure 1 (The dotted line in the attached figure is quoted from the national standard GB / T24853-2010):

[0126] Table 1: Heating program

[0127] Time (HH:MM:SS) Temperature 00:00:00 50 00:01:00 50 00:04:42 95 00:07:12 95 00:11:00 50 00:13:00 END

[0128] Wherein, ΔCP represents the difference between the viscosity at 95°C (360 seconds) and the average of all viscosities between 50°C and 65°C (the average value is calculated based on the average of 10 monitoring points).

[0129] V95 means: the stability evaluation value of the 95℃ constant temperature section (320s to 436s), using the formula 2×STDEV(CP 320 :CP 436) to calculate the V95 value.

[0130] White brightness L / (a+b) determination:

[0131] Calculated based on the flour processing precision tester.

[0132] Protein content determination :

[0133] Determined according to the Kjeldahl method.

[0134] (Source of raw materials)

[0135] The grains used in the following examples and comparative examples were all commercially available products.

[0136] Commercially available seeds 1: produced in Dingbian, Shaanxi;

[0137] Commercially available seeds 2: produced in Hohhot, Inner Mongolia;

[0138] Commercially available seeds 3: produced in Baotou, Inner Mongolia;

[0139] Commercially available grains 4: Origin: Datong, Shanxi.

[0140] (Grading Processing)

[0141] Buckwheat kernels of various shells were purchased from the market. After cleaning, grinding, screening, powder purifying, and blending, 20-30 different powder tubes were produced. These tubes were then classified and combined into first-grade, second-grade, and third-grade flours based on the values ​​of three indicators: water-soluble matter content, white brightness (L / (a+b)), and total protein content (%, dry basis). The specific grading index ranges are shown in Table 2 below:

[0142] Table 2:

[0143] sample Water-soluble matter content% White brightness L / (a+b) Total protein content (%, dry basis) Level 1 powder 1-10％ 3.3-7.2 4-14 Secondary powder 10-28％ 2.2-2.7 14-30 Level 3 powder ＞28％ 0-2.0 30-40

[0144] The commercially available grains were milled to obtain corresponding graded powder samples. The key parameter results are shown in Table 3:

[0145] Table 3:

[0146]

[0147] Example 1:

[0148] A mixed buckwheat flour (commercially available first-grade grain flour and second-grade grain flour, mixed in a ratio of 90:10) has a water-soluble matter content of 3.4%, a ΔCP value of 2200 mPa·s, and a V95 value of 120. The mixed buckwheat flour stabilizes buckwheat slurry and prevents stratification. After steaming, the resulting gel has a moderate texture (neither soft nor brittle), with no noticeable water precipitation in the center of the container.

[0149] Example 2:

[0150] A mixed buckwheat flour (commercially available first-grade grain flour and second-grade grain flour, blended in a ratio of 85:15) has a water-soluble matter content of 4.6%, a ΔCP value of 1750 mPa·s, and a V95 value of 105. This flour stabilizes buckwheat slurry and prevents stratification. After steaming, the resulting gel has a moderate texture (neither soft nor brittle), with no noticeable water precipitation in the center of the container.

[0151] Example 3:

[0152] A mixed buckwheat flour (commercially available first-grade grain flour and second-grade grain flour, mixed in a ratio of 95:5) has a water-soluble matter content of 7.4%, a ΔCP value of 2450 mPa·s, and a V95 value of 135. This flour stabilizes buckwheat slurry and prevents stratification. After steaming, the resulting gel has a moderate texture (neither soft nor brittle), with no noticeable water precipitation in the center of the container.

[0153] Example 4:

[0154] A mixed buckwheat flour (commercially available grain 4-grade flour, commercially available grain 1-grade flour, and commercially available grain 2-grade flour, mixed in a ratio of 90:5:5) has a water-soluble matter content of 7.2%, a ΔCP value of 2100 mPa·s, and a V95 value of 118. The mixed buckwheat flour stabilizes buckwheat slurry and prevents stratification. After steaming, the resulting gel has a moderate texture (neither soft nor brittle), with no noticeable water precipitation in the center of the container.

[0155] Example 5

[0156] A mixed buckwheat flour (commercially available grain 2-grade flour, commercially available grain 4-grade flour, and commercially available grain 1-grade flour, mixed in a ratio of 45:45:10) has a water-soluble matter content of 5.0%, a ΔCP value of 2260 mPa·s, and a V95 value of 132. The mixed buckwheat flour stabilizes buckwheat slurry and prevents stratification. After steaming, the resulting gel has a moderate texture (neither soft nor brittle), with no noticeable water precipitation in the center of the container.

[0157] Example 6

[0158] A mixed buckwheat flour (commercially available grain 1-first-grade flour, commercially available grain 2-first-grade flour, commercially available grain 3-first-grade flour, commercially available grain 2-second-grade flour, commercially available grain 3-second-grade flour, and commercially available grain 4-second-grade flour, blended in a ratio of 30:30:30:3:3:4) has a water-soluble matter content of 5.2%, a ΔCP value of 2310 mPa·s, and a V95 value of 129. The mixed buckwheat flour stabilizes buckwheat slurry and prevents stratification. After steaming, the gel has a moderate texture (neither soft nor brittle), and there is no noticeable water precipitation in the center of the container.

[0159] Comparative Example 1

[0160] A mixed buckwheat flour (commercially available Grain 1 (first-grade flour) and commercially available Grain 2 (second-grade flour) mixed in an 80:20 ratio) has a water-soluble matter content of 3.2%, a ΔCP value of 890 mPa·s, and a V95 value of 77. Buckwheat slurry produced by steaming exhibits rapid and distinct stratification, and the steamed gel is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0161] Comparative Example 2

[0162] A mixed buckwheat flour (commercially available grain 2 (first-grade flour) and commercially available grain 3 (second-grade flour) in a 98:2 ratio) has a water-soluble content of 2.1%, a ΔCP value of 2510 mPa·s, and a V95 value of 166. Buckwheat slurry produced by steaming exhibits rapid and distinct stratification, and the steamed gel is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0163] Comparative Example 3

[0164] A mixed buckwheat flour (commercially available grain 3-grade flour, commercially available grain 4-grade flour, and commercially available grain 2-grade flour, mixed in a ratio of 43:40:17) has a water-soluble matter content of 8.4%, a ΔCP value of 1020 mPa·s, and a V95 value of 114. The prepared buckwheat slurry exhibits rapid and distinct stratification, and the steamed gel is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0165] Comparative Example 4

[0166] A mixed buckwheat flour (commercially available grain 4-grade flour, commercially available grain 1-grade flour, and commercially available grain 3-grade flour, mixed in a ratio of 96:2:2) has a water-soluble matter content of 6.9%, a ΔCP value of 2480 mPa·s, and a V95 value of 164. Buckwheat slurry produced by steaming exhibits rapid and distinct stratification, and the gel texture after steaming is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0167] Comparative Example 5

[0168] A mixed buckwheat flour (commercially available grain 1-level flour, commercially available grain 2-level flour, commercially available grain 3-level flour, commercially available grain 1-level flour, commercially available grain 3-level flour, commercially available grain 4-level flour, mixed in a ratio of 35:29:20:5:5:6) has a water-soluble matter content of 5.4%, a ΔCP value of 670 mPa·s, and a V95 value of 109. Buckwheat slurry produced quickly and distinctly separates, and after steaming, the gel texture is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0169] Comparative Example 6

[0170] A mixed buckwheat flour (commercially available first-grade, second-grade, and third-grade grains mixed in a 90:5:5 ratio) has a water-soluble content of 4.7%, a ΔCP value of 550 mPa·s, and a V95 value of 63. Buckwheat slurry produced quickly and distinctly separates, and after steaming, the gel texture is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0171] Comparative Example 7

[0172] A mixed buckwheat flour (commercially available grain 2 (first-grade flour), commercially available grain 3 (second-grade flour), and commercially available grain 4 (third-grade flour) in a ratio of 85:5:10) has a water-soluble matter content of 6.5%, a ΔCP value of 620 mPa·s, and a V95 value of 56. Buckwheat slurry produced quickly and distinctly separates, and after steaming, the gel texture is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0173] Comparative Example 8

[0174] A mixed buckwheat flour (commercially available grain 2-first-grade flour, commercially available grain 4-first-grade flour, commercially available grain 1-second-grade flour, commercially available grain 2-second-grade flour, commercially available grain 3-third-grade flour, and commercially available grain 4-third-grade flour, blended in a ratio of 45:43:5:4:2:1) has a water-soluble matter content of 5.7%, a ΔCP value of 960 mPa·s, and a V95 value of 82. Buckwheat slurry undergoes rapid and distinct stratification, and after steaming, the gel texture is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0175] Comparative Example 9

[0176] Buckwheat flour (commercially available whole grain 1) has a water-soluble matter content of 12.4%, a ΔCP value of 610 mPa·s, and a V95 value of 55. Buckwheat slurry produced by steaming exhibits rapid and distinct stratification, and the gel texture after steaming is either too soft or too hard and brittle, with noticeable sedimentation and even water precipitation in the center of the container.

[0177] Test Example 1

[0178] Buckwheat slurries were prepared using the buckwheat flour of Examples 1-6 and Comparative Examples 1-8, respectively. The slurries were tested using a Turbiscan Lab stability analyzer. 20 g of buckwheat flour sample was weighed and 80 g of deionized water were stirred for 10 min until the sample was uniform and free of lumps and particles. 20 mL of the sample was then transferred to a sample bottle for analysis. The test temperature was 30° C., the test duration was 180 min, and a scan was performed every 30 s. The TSI value at 180 min was used as an indicator for evaluating the slurry stability. (TSI stands for slurry stability kinetic index, which refers to the cumulative change in backscattered light or transmitted light intensity from each measurement compared to the previous measurement during the measurement time. It reflects the combined changes in the sample volume concentration and particle size over the entire measurement time. The greater the sample change, the larger the TSI value, and the more unstable the system.)

[0179] The statistical results are shown in Tables 4 and 5:

[0180] Table 4:

[0181]

[0182] Table 5:

[0183]

[0184] The above viscosity test results show that although the various examples used commercially available grains from different sources, the buckwheat flour after mixing them met the physical and chemical properties specified in the present invention. Therefore, the stability of the obtained products was very close to each other.

[0185] Test Example 2

[0186] Steamed products were prepared using the buckwheat flour of Examples 1-5 and Comparative Examples 1-8, respectively. The preparation method was based on the existing literature ("Study on the Quality Characteristics of Buckwheat Flour of Different Grades", Wang Yijing, Northwest Agriculture and Forestry University, Master's Degree Thesis, 2017): the ratio of buckwheat flour to distilled water was 1:4, clean water was added to the buckwheat flour and stirred until it became viscous and free of particles, and the batter slid quickly into a thin line when picked up with chopsticks. The prepared buckwheat paste was poured into a porcelain bowl of appropriate size, placed in a steamer, and steamed for 10 minutes after steaming. The heat was turned off. After the steamed buckwheat gel was cooled to room temperature, it was poured out and set aside for evaluation.

[0187] The sensory evaluation panel consisted of 20 people who used descriptive analysis to judge the steamed buckwheat products. First, each judge independently judged the appearance and texture of the product, and finally everyone discussed and gave an evaluation score.

[0188] Table 6: Scoring criteria

[0189]

[0190] Table 7: Sensory evaluation scores of steamed buckwheat products

[0191]

[0192] The above test results show that the slurries prepared using the buckwheat flour of Examples 1-6 have excellent stability and low TSI values, and the appearance, texture and sensory evaluation of the steamed products are excellent.

[0193] Comparative Examples 2, 4, 5, and 8 exhibited excellent slurry stability and low TSI values, but received low sensory evaluation scores, resulting in a soft or brittle product texture. Comparative Examples 1, 3, 6, and 7 exhibited poor slurry stability, high TSI values, and low sensory evaluation scores, as evidenced by significant sedimentation and water precipitation. Overall, the present invention significantly improved the slurry stability, appearance, and texture of steamed buckwheat products compared to the comparative examples.

[0194] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present disclosure should not be limited thereto.

[0195] While various embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0196] Industrial applicability

[0197] The buckwheat flour of the present invention can be industrially prepared and used in food production.

Claims

1. A method for preparing buckwheat flour suitable for preparing paste-type steamed food, characterized in that: include: a grading step for grading buckwheat flour obtained by processing buckwheat grains according to the water-soluble matter content, the whiteness L / (a+b) value calculated according to the CIE colorimetric, and the total protein content; a mixing step of mixing the graded buckwheat flours according to a measured ratio; Wherein, the water-soluble substance content and total protein content are the contents based on the dry weight of buckwheat flour. The classification step produces first-grade buckwheat flour, second-grade buckwheat flour, and optionally third-grade buckwheat flour, wherein: The first-grade buckwheat flour has a water-soluble matter content of 1 to 10% by mass, an L / (a+b) value of 3 to 7.5, and a total protein content of 4 to 14% by mass; The secondary buckwheat flour has a water-soluble matter content of 11% to 25% by mass, an L / (a+b) value of 2.2 to 2.7, and a total protein content of 15% to 25% by mass; The third-grade buckwheat flour has a water-soluble matter content of greater than 28% by mass, an L / (a+b) value of less than 2, and a total protein content of greater than 30% by mass; In the mixing step, the first-grade buckwheat flour and the second-grade buckwheat flour are mixed at a mass ratio of 85-95:15-5; the content of the third-grade buckwheat flour is 2.5% by mass or less based on the total mass of the buckwheat flour. The total content of the water-soluble substances is 1 to 13% by mass based on the dry weight of the buckwheat flour.

2. Buckwheat flour obtained by the method according to claim 1, The buckwheat flour has: The content of water-soluble matter is 1 to 13% by weight based on the dry weight of buckwheat flour; ΔCP value is 1500~2600mPa•s; V95 value is below 160; in: ΔCP value means: CP measured according to standard procedure 1 in GB / T 24853-2010 95 - The value of CP1, where CP 95 is the viscosity value at 95°C recorded 360 seconds after the temperature control program is started, and CP1 is the average viscosity value within the range of 50-65°C in the temperature rise stage of the temperature control program; V95 value means: 2×STDEV (CP 320 :CP 436 ) value, where STDEV(CP 320 :CP 436 ) represents the value of the standard deviation function of the viscosity values ​​at 95°C from 320s to 436s.

3. The buckwheat flour according to claim 2, characterized in that The V95 value is 100-140.

4. Flour, characterized in that The flour comprises the buckwheat flour according to claim 2 or 3.

5. A food product, characterized in that The food is obtained by processing the flour according to claim 4.

6. The food product according to claim 5, characterized in that The food products include bowl dumplings, sausages or noodle foods.

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