A series of wheat flour standard substances with different mineral element contents, their preparation methods, and their application in the analysis of the distribution characteristics of trace mineral elements in wheat.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-22
- Publication Date
- 2026-08-14
AI Technical Summary
传统确定小麦籽粒矿质元素含量分布的方法是籽粒经过组织机械分离分为不同层，然后利用化学分析确定各层矿质元素含量，其优点定量准确性高，缺点是完全丢失空间信息，且样品被完全破坏，无法进行后续分析
本发明提供的制备方法根据小麦粉基体矿质元素含量和预研制小麦粉标准物质的目标矿质元素含量，按照公式计算确定小麦粉基体中需要添加的矿质元素的量，将已知矿质元素含量的国家液体标准物质配制成溶液均匀喷洒在小麦粉基体中，配合烘干、研磨、混匀、过筛流程，获得矿质元素不同含量梯度的小麦粉标准物质，为原位监测小麦籽粒矿质元素含量量化提供标准曲线，帮助理解籽粒矿质元素运移提供了技术支撑。
Smart Images
Figure CN122567332A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of plant standard material preparation technology, specifically relating to a series of wheat flour standard materials with different mineral element contents, their preparation methods, and their application in the analysis of the distribution characteristics of trace mineral elements in wheat. Background Technology
[0002] Wheat, a staple food crop for Chinese residents, is a major source of minerals for the human body. With rising living standards, consumers are demanding higher quality wheat, with wheat rich in zinc, iron, and selenium gaining popularity. However, wheat grains are generally low in iron, zinc, and selenium, leading to deficiencies in these elements, particularly in developing countries and regions. Conversely, wheat grains are rich in certain elements, such as manganese, which pose non-carcinogenic risks in some countries and regions. Therefore, research on the mineral content of wheat grains has received widespread and significant attention in the agricultural field.
[0003] The mineral element content varies greatly among different tissues of wheat grains. In the endosperm, the main part ingested dietaryly, the zinc, iron, and manganese content is only about 10 mg / kg, 15 mg / kg, and 10 mg / kg, respectively. However, the aleurone layer, embryo, and folded tissue have zinc content as high as 100 mg / kg, 200 mg / kg, and 300 mg / kg, respectively; iron content as high as 450 mg / kg, 290 mg / kg, and 150 mg / kg, respectively; and manganese content as high as 60 mg / kg, 300 mg / kg, and 300 mg / kg, respectively. Investigating the distribution of mineral elements in wheat grains is crucial for increasing the content of beneficial elements in wheat grains, avoiding excessive levels of harmful heavy metals, and understanding the transport of mineral elements within the grain. Traditional methods for determining the distribution of mineral elements in wheat grains involve mechanically separating the grain into different layers and then using chemical analysis to determine the mineral element content of each layer. While this method offers high quantitative accuracy, it completely loses spatial information and destroys the sample, making further analysis impossible. Synchrotron radiation X-ray fluorescence, laser ablation inductively coupled plasma mass spectrometry, and micro-beam proton X-ray fluorescence analysis, compared to the mechanical separation of grain tissue, can determine the distribution of mineral elements in plant tissue in situ, providing in situ spatial distribution information of mineral elements. These techniques are relatively minimally invasive or non-invasive, but quantitative analysis requires a series of standard substances with different concentration gradients.
[0004] Currently, wheat standard materials or samples available on the domestic and international markets have single concentrations and low content, lacking different concentration gradients. Therefore, standard curve fitting is impossible when determining the distribution of various mineral elements in wheat grains in situ, leading to inaccurate quantification. For example, wheat flour standard materials GBW10011(GSB-2), GBW10011a(GSB-2a), and GBW10046(GSB-24) produced by the Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences; GBW1086 and GBW10187 produced by Beijing University of Chemical Technology and Tanmo Quality Inspection Technology Co., Ltd.; and GBW(E)100493~100496 produced by Steel Research Institute Nake Testing Technology Co., Ltd., etc., only contain the content of mineral elements in wheat flour (mainly endosperm), which is far lower than the content in the aleurone layer, embryo, folded tissue, and other tissues. Therefore, developing a series of wheat flour standard materials with different concentrations is of great significance for conducting in-situ monitoring of mineral elements and analysis of nutrient transport in wheat grains. Summary of the Invention
[0005] The purpose of this invention is to provide a series of wheat flour standard substances with different mineral element contents, their preparation methods, and their application in the analysis of trace mineral element distribution characteristics in wheat. The preparation method provided by this invention can prepare a series of wheat flour standard substances with different mineral element contents.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a series of wheat flour standard substances with different mineral element contents, comprising the following steps: (1) Determine the content of mineral elements in wheat flour matrix; (2) Determine the amount of mineral element standard material to be added to the wheat flour matrix based on the target content of mineral elements in the wheat flour standard material. (3) According to the amount of mineral element standard material determined in step (2), mix the mineral element standard material with the wheat flour matrix to obtain a series of wheat flour standard materials with different mineral element contents.
[0007] Preferably, the mineral elements in step (1) include one of calcium, potassium, magnesium, sodium, iron, phosphorus, zinc, copper, manganese, boron, barium, molybdenum, cobalt, chromium, lithium, strontium, nickel, sulfur, vanadium, selenium and rubidium.
[0008] Preferably, in step (2), the amount of mineral element standard substance to be added to the wheat flour matrix is determined according to formula I: V g =(C tar -C fou )×M fou / C g Formula I; In Equation I, V g The amount of mineral element standard material used is expressed in mL; C tar The target content of mineral elements in wheat flour standard reference material, in mg / kg; C fou The content of mineral elements in wheat flour matrix, in mg / kg, M fou The mass of the wheat flour matrix is expressed in grams (g); C g This represents the concentration of the mineral element standard reference material, expressed in µg / mL.
[0009] Preferably, the mixing method of the mineral element standard substance and the wheat flour matrix in step (3) is as follows: the mineral element standard substance is mixed with water to obtain a diluted solution, and the diluted solution is sprayed into the wheat flour matrix.
[0010] Preferably, the volume of the diluent is no more than 1 / 3 of the mass of the wheat flour matrix.
[0011] Preferably, step (3) further includes drying, grinding, mixing and sieving in sequence after the mineral element standard substance and wheat flour matrix are mixed.
[0012] Preferably, the drying temperature is 35~45℃.
[0013] Preferably, the mesh size of the sieve used during sieving is 40 mesh.
[0014] This invention also provides a series of wheat flour standard substances with different mineral element contents prepared by the preparation method described in the above technical solution.
[0015] This invention also provides the application of the series of wheat flour standard substances with different mineral element contents described in the above technical solution in the analysis of the distribution characteristics of trace mineral elements in wheat.
[0016] This invention provides a method for preparing a series of wheat flour standard substances with different mineral element contents, comprising the following steps: (1) determining the content of mineral elements in the wheat flour matrix; (2) determining the amount of mineral element standard substance to be added to the wheat flour matrix according to the target content of mineral elements in the wheat flour standard substance; (3) mixing the mineral element standard substance with the wheat flour matrix according to the amount of mineral element standard substance determined in step (2) to obtain a series of wheat flour standard substances with different mineral element contents. The preparation method provided by this invention, based on the mineral element content in the wheat flour matrix and the target mineral element content in the pre-prepared wheat flour standard substance, mixes the mineral element standard substance with known mineral element content with the wheat flour matrix to prepare a series of wheat flour standard substances with different mineral element contents, providing a standard curve for in-situ monitoring of the quantification of mineral element content in wheat grains, and providing technical support for understanding the migration of mineral elements in grains. Attached Figure Description
[0017] Figure 1 A flowchart illustrating the preparation method of a series of wheat flour standard substances with different mineral element contents provided by the present invention; Figure 2 This is a graph showing the zinc content distribution of wheat grain slices in Application Example 1; Figure 3 This is a distribution diagram of manganese content in wheat grain slices from Application Example 2. Detailed Implementation
[0018] This invention provides a method for preparing a series of wheat flour standard substances with different mineral element contents, comprising the following steps: (1) Determine the content of mineral elements in wheat flour matrix; (2) Determine the amount of mineral element standard material to be added to the wheat flour matrix based on the target content of mineral elements in the wheat flour standard material. (3) According to the amount of mineral element standard material determined in step (2), mix the mineral element standard material with the wheat flour matrix to obtain a series of wheat flour standard materials with different mineral element contents.
[0019] This invention determines the content of mineral elements in wheat flour matrix.
[0020] In one embodiment, the mineral element may include one of calcium, potassium, magnesium, sodium, iron, phosphorus, zinc, copper, manganese, boron, barium, molybdenum, cobalt, chromium, lithium, strontium, nickel, sulfur, vanadium, selenium, and rubidium.
[0021] This invention does not impose any specific limitations on the method for determining the mineral element content in wheat flour matrix; any technical solution well-known to those skilled in the art can be used. As one embodiment, this invention uses the method described in either the National Food Safety Standard "Determination of Multiple Elements in Food" or the "Inspection of Grains and Oils: Determination of Calcium, Potassium, Magnesium, Sodium, Iron, Phosphorus, Zinc, Copper, Manganese, Boron, Barium, Molybdenum, Cobalt, Chromium, Lithium, Strontium, Nickel, Sulfur, Vanadium, Selenium, and Rubidium Content in Grains and Their Products - Inductively Coupled Plasma Atomic Emission Spectrometry" to determine the mineral element content in wheat flour matrix.
[0022] After determining the content of mineral elements in the wheat flour matrix, this invention determines the amount of mineral element standard material to be added to the wheat flour matrix based on the target content of mineral elements in the wheat flour standard material.
[0023] This invention does not impose any specific limitations on the target content of mineral elements in the wheat flour standard material; the content can be selected according to actual needs. As one embodiment, when the mineral element in the wheat flour standard material is zinc, the zinc content can be 10.3 mg / kg, 25 mg / kg, 50 mg / kg, 100 mg / kg, and 150 mg / kg, respectively; when the mineral element in the wheat flour standard material is manganese, the manganese content can be 16.7 mg / kg, 50 mg / kg, 100 mg / kg, 200 mg / kg, and 300 mg / kg, respectively.
[0024] As one implementation method, the mineral element standard material may specifically be a national liquid standard material; the solvent of the national liquid standard material may be water or nitric acid; the zinc standard material may specifically be the national zinc single-element solution standard material GBW(E)085716, and the manganese standard material may specifically be the national manganese single-element solution standard material GBW(E)080157.
[0025] In one implementation method, the present invention determines the amount of mineral element standard material to be added to the wheat flour matrix according to Formula I: V g =(C tar -C fou )×M fou / C g Formula I; In Equation I, V g The amount of mineral element standard material used is expressed in mL; C tar The target content of mineral elements in wheat flour standard reference material, in mg / kg; C fou The content of mineral elements in wheat flour matrix, in mg / kg, M fou The mass of the wheat flour matrix is expressed in grams (g); C g This represents the concentration of the mineral element standard reference material, expressed in µg / mL.
[0026] After determining the amount of mineral element standard substances to be added to the wheat flour matrix, the present invention mixes the mineral element standard substances with the wheat flour matrix according to the determined amount of mineral element standard substances to obtain a series of wheat flour standard substances with different mineral element contents.
[0027] As one implementation method, the mixing of the mineral element standard material and the wheat flour matrix can be: mixing the mineral element standard material with water to obtain a diluted solution, and spraying the diluted solution into the wheat flour matrix.
[0028] In one implementation method, the water is ultrapure water.
[0029] In one embodiment, the volume of the diluent is no more than 1 / 3 of the mass of the wheat flour matrix. This invention controls the amount of diluent used to prevent excessive diluent from causing difficulties in drying the wheat flour. In one embodiment, when the mass of the wheat flour matrix is 200 g, the volume of the diluent can specifically be 30 mL or 60 mL.
[0030] In one embodiment, the present invention uses a nano-scale ultrafine spray bottle to uniformly spray the diluent onto the wheat flour matrix. The present invention does not have any particular limitations on the source or model of the nano-scale ultrafine spray bottle; commercially available equipment well known to those skilled in the art can be used.
[0031] As one implementation, the mixing of the mineral element standard material and the wheat flour matrix may further include sequential drying, grinding, mixing, and sieving.
[0032] In one embodiment, the drying temperature can be 35~45℃, or more specifically 40℃; the drying is carried out without forced air. The present invention does not have a specific limitation on the drying time; drying to constant weight is sufficient.
[0033] In one embodiment, the grinding is performed in a ball mill; the grinding jar of the ball mill can be made of zirconium oxide or stainless steel. This invention does not impose any special limitations on other grinding operations; grinding methods well known to those skilled in the art can be used.
[0034] As one implementation method, the present invention uses a quartering method for mixing; the quartering method can be specifically described as follows: the ground wheat flour is divided into four parts, and two diagonally opposite parts are mixed, and this step is repeated 10 to 15 times.
[0035] In one implementation, the mesh size of the sieve during sieving can be 40 mesh; the number of sieving cycles can be 10 to 15.
[0036] The grinding, mixing, and sieving processes of this invention enable a more uniform mixing of the wheat flour matrix and the mineral element standard substances.
[0037] As one implementation method, after sieving, the present invention can detect the content of mineral elements in wheat flour standard material; the detection method can be the same as the aforementioned method for determining the content of mineral elements in wheat flour matrix.
[0038] Compared with the prior art, the present invention has the following beneficial technical effects: The preparation method provided by this invention calculates the amount of mineral elements to be added to the wheat flour matrix according to the mineral element content of the wheat flour matrix and the target mineral element content of the pre-developed wheat flour standard material, and then uniformly sprays the solution of the national liquid standard material with known mineral element content into the wheat flour matrix. Combined with the drying, grinding, mixing and sieving process, wheat flour standard materials with different mineral element content gradients are obtained. This provides a standard curve for in-situ monitoring of the mineral element content of wheat grains and provides technical support for understanding the migration of mineral elements in grains.
[0039] The preferred flowchart of the preparation method provided by the present invention is as follows: Figure 1 As shown.
[0040] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0041] Example 1 A method for preparing a series of wheat flour standard substances with different zinc contents is as follows: (1) The zinc content in wheat flour matrix was determined to be 10.3 mg / kg according to the National Food Safety Standard for Determination of Multiple Elements in Food (GB 5009.268-2016); (2) Determine the amount of mineral element standard material (national zinc single element solution standard material GBW(E)085716) to be added to the wheat flour matrix according to Formula I: V g =(C tar -C fou )×M fou / C g Formula I; Among them, C tar =10.3, 25, 50, 100, 150 mg / kg, C fou =10.3 mg / kg, M fou =200 g, C g =1000 µg / mL; Substituting the above values into the formula, the amounts of GBW(E)085716 added are as follows: 10.3 mg / kg wheat flour standard reference: V g =(10.3-10.3)×200 / 1000=0 mL, 25 mg / kg wheat flour standard reference: V g=(25-10.3)×200 / 1000=2.9 mL, 50 mg / kg wheat flour standard reference: V g =(50-10.3)×200 / 1000=7.9 mL, 100 mg / kg wheat flour standard reference: V g =(100-10.3)×200 / 1000=17.9 mL, 150 mg / kg wheat flour standard reference: V g =(150-10.3)×200 / 1000=27.9 mL, (3) 2.9 mL, 7.9 mL, 17.9 mL and 27.9 mL of GBW(E)085716 were diluted with ultrapure water to 30 mL, respectively, and put into a nano-scale ultrafine spray bottle. The mixture was evenly sprayed into 200 g of wheat flour, and then dried in an oven at 40°C without forced air to constant weight. The mixture was then ground in a ball mill, mixed 15 times by quartering, and passed through a 40-mesh nylon sieve 15 times to obtain a series of wheat flour standard substances with different zinc contents. (4) The final zinc contents of the series of wheat flour standard substances with different zinc contents obtained by step (3) were 10.3, 24.8, 49.6, 99.8 and 148.3 mg / kg, respectively, according to the National Food Safety Standard for Determination of Multiple Elements in Food (GB 5009.268-2016).
[0042] Application Example 1 In-situ monitoring of zinc distribution in wheat grains using synchrotron radiation: Wheat grains were soaked in liquid nitrogen for 30 min and embedded using Tissue Tek embedding agent. The samples were then placed in a -20℃ cryostat and sliced into 60 μm thick sections. The prepared grain sections were fixed onto the surface of polyimide tape, sealed with plastic wrap, and then dried in a freeze dryer at -53℃ and 0.140 mbar for 1 h. After drying, the samples were sealed and stored. Wheat flour standard materials with zinc content gradients of 10.3, 24.8, 49.6, 99.8, and 148.3 mg / kg prepared in Example 1 were uniformly coated on polyimide tape. Using the Stanford Synchrotron Radiation Beamline 2-3 in the United States, X-ray fluorescence was used to scan the wheat flour standard materials, wheat grain slices, and blank polyimide tape with different zinc content gradients. The instrument parameters were set as follows: horizontal step size 20 μm, vertical step size 30 μm, and single-point acquisition dwell time 20 s. After subtracting the background fluorescence signal from the polyimide tape, a quadratic parabolic curve was established for zinc quantification by using the corrected XRF fluorescence signals of wheat flour standards with different zinc contents as the dependent variable and the corresponding zinc content as the independent variable. The corrected fluorescence signals from the grain slices were then substituted into the fitted standard curve to calculate the zinc content in each region of the wheat grain slices. Finally, the spatial distribution map of zinc in wheat grains was plotted using Origin 2017 SR2 software. The results are shown below. Figure 2 As shown. From Figure 2 It can be seen that the zinc content of wheat grains is much higher in the embryo, aleurone layer, and folded tissue than in the endosperm.
[0043] Example 2 A method for preparing a series of wheat flour standard substances with different manganese contents is as follows: (1) The content of manganese in wheat flour matrix was determined to be 16.7 mg / kg according to the National Food Safety Standard for Determination of Multiple Elements in Food (GB 5009.268-2016); (2) Determine the amount of mineral element standard material (national manganese single element solution standard material GBW(E)080157) to be added to the wheat flour matrix according to Formula I: V g =(C tar -C fou )×M fou / C g Formula I; Among them, C tar =16.7, 50, 100, 200, 300 mg / kg, C fou =16.7 mg / kg, M fou =200 g, C g =1000 µg / mL, Substituting the above values into the formula, the amounts of GBW(E)080157 added are as follows: 16.7 mg / kg wheat flour standard reference: V g =(16.7-16.7)×200 / 1000=0 mL, 50 mg / kg wheat flour standard reference: V g =(50-16.7)×200 / 1000=6.7 mL, 100 mg / kg wheat flour standard reference: V g =(100-16.7)×200 / 1000=16.7 mL, 200 mg / kg wheat flour standard reference: V g=(200-16.7)×200 / 1000=36.7 mL, 300 mg / kg wheat flour standard reference: V g =(300-16.7)×200 / 1000=56.7 mL, (3) 6.7 mL, 16.7 mL, 36.7 mL and 56.7 mL of GBW(E)080157 were diluted with ultrapure water to 60 mL, respectively, and put into nano-scale ultrafine spray bottles. The mixture was evenly sprayed into 200 g of wheat flour, dried in an oven at 40℃ without forced air until constant weight, ground in a ball mill, mixed 15 times by quartering, and passed through a 40-mesh nylon sieve 15 times to obtain a series of wheat flour standard substances with different manganese contents; (4) The final manganese content in a series of wheat flour standard substances with different manganese contents was determined to be 16.7, 49.8, 99.5, 198.9 and 298.1 mg / kg, respectively, using the national food safety standard "Determination of multiple elements in food" (GB 5009.268-2016).
[0044] Application Example 2 Using the same method as in Application Example 1, in-situ monitoring of manganese distribution in wheat grains was conducted via synchrotron radiation. The resulting spatial distribution map of manganese in wheat grains is shown below. Figure 3 As shown. From Figure 3 It can be seen that the embryo in wheat grains has the highest manganese content, followed by the folded tissue, scutellum and aleurone layer, and the endosperm has the lowest.
[0045] In summary, this invention has prepared a series of wheat flour standard substances with different mineral element contents, providing standard curves for in-situ monitoring of the mineral element content of wheat grains and providing technical support for understanding the migration of mineral elements in grains.
[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a series of wheat flour standard substances with different mineral element contents, comprising the following steps: (1) Determine the content of mineral elements in wheat flour matrix; (2) Determine the amount of mineral element standard material to be added to the wheat flour matrix based on the target content of mineral elements in the wheat flour standard material. (3) According to the amount of mineral element standard material determined in step (2), mix the mineral element standard material with the wheat flour matrix to obtain a series of wheat flour standard materials with different mineral element contents.
2. The preparation method according to claim 1, characterized in that, The mineral elements in step (1) include one of the following: calcium, potassium, magnesium, sodium, iron, phosphorus, zinc, copper, manganese, boron, barium, molybdenum, cobalt, chromium, lithium, strontium, nickel, sulfur, vanadium, selenium, and rubidium.
3. The preparation method according to claim 1, characterized in that, In step (2), the amount of mineral element standard substance to be added to the wheat flour matrix is determined according to formula I: V g =(C tar -C fou )×M fou / C g Formula I; In Equation I, V g The amount of mineral element standard material used is expressed in mL; C tar The target content of mineral elements in wheat flour standard reference material, in mg / kg; C fou The content of mineral elements in wheat flour matrix, in mg / kg, M fou The mass of the wheat flour matrix is expressed in grams (g); C g This represents the concentration of the mineral element standard reference material, expressed in µg / mL.
4. The preparation method according to claim 1, characterized in that, The mixing method of the mineral element standard material and the wheat flour matrix in step (3) is as follows: the mineral element standard material is mixed with water to obtain a diluted solution, and the diluted solution is sprayed into the wheat flour matrix.
5. The preparation method according to claim 4, characterized in that, The volume of the diluent shall not exceed 1 / 3 of the mass of the wheat flour matrix.
6. The preparation method according to claim 1, characterized in that, The steps in step (3) include drying, grinding, mixing and sieving in sequence after the mineral element standard material and wheat flour matrix are mixed.
7. The preparation method according to claim 6, characterized in that, The drying temperature is 35~45℃.
8. The preparation method according to claim 6, characterized in that, The sieve used during sieving has a mesh size of 40.
9. A series of wheat flour standard substances with different mineral element contents prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the series of wheat flour standard substances with different mineral element contents as described in claim 9 in the analysis of the distribution characteristics of trace mineral elements in wheat.