A method for producing a medium glycemic index wheat flour by regulating the distance between the skin mill and the heart mill rollers
Patent Information
- Application Number
- CN202611044203.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-14
- Publication Date
- 2026-08-28
AI Technical Summary
[0005]本发明的目的在于，提供一种通过调控皮磨与心磨辊间距制备中等升糖指数小麦粉的方法，以解决现有制粉工艺中难以兼顾出粉率、淀粉完整性及淀粉升糖特性协同控制的技术问题
与现有技术相比，本发明具有以下显著有益效果：
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of food processing technology, and in particular relates to a method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers. Background Technology
[0002] Wheat is the most important staple food for urban and rural residents in my country. Wheat milling is a process that uses mechanical force to separate the bran, germ, and endosperm layer by layer, and grinds the endosperm into fine powder. In the milling process, the roller gap between the bran mill and the endosperm mill is a key process parameter that affects milling efficiency and the quality of the finished product.
[0003] Existing research indicates that the roller spacing directly affects the starch structure, gluten network, and digestibility of wheat flour. For example, too small a roller spacing leads to excessive breakage of starch granules, increasing the content of damaged starch, which in turn accelerates the enzymatic hydrolysis process, increasing the starch hydrolysis rate and glycemic response. Conversely, a reasonable roller spacing setting can maintain the integrity of starch granules while ensuring flour yield and delaying starch digestion. The newly revised wheat flour quality standards have also incorporated the refined control of the milling process into consideration.
[0004] However, current research largely focuses on the impact of individual milling roller spacing on overall wheat flour quality, while systematic studies on the synergistic control of bran and endosperm milling, and the differences in starch and digestibility characteristics of wheat flour from different milling paths remain relatively weak. In particular, there is a lack of in-depth analysis of the intrinsic relationship between milling processes, starch damage levels, and glycemic index. Therefore, developing a method for the targeted preparation of medium glycemic index wheat flour through precise control of the bran and endosperm mill roller spacing has significant industrial application value. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing medium glycemic index (EGI) wheat flour by controlling the distance between the bran mill and the endosperm mill rollers, thereby solving the technical problem in existing milling processes of simultaneously controlling flour yield, starch integrity, and starch glycemic properties. By synergistically controlling the distance between the bran mill and the endosperm mill rollers, the in vitro glycemic index (EGI) of the wheat flour can be controlled to ≤70 (medium GAI). This invention establishes a method for synergistically controlling the distance between the bran mill and the endosperm mill rollers, revealing the mechanism by which the bran mill distance dominates processing precision and the endosperm mill distance dominates starch digestibility. By reasonably widening the roller distance, starch granule integrity can be preserved while ensuring flour yield, significantly delaying starch digestion and reducing EGI, making it suitable for the industrial production of medium GAI-specific wheat flour.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers includes the following steps: (1) Raw material pretreatment: Select wheat varieties with a hardness index of 65~70, clean, remove stones and impurities, and then moisten the wheat. Control the moisture content of the wheat to 14.5%~15.5% and moisten the wheat at room temperature for 20-24 hours. (2) Adjustment of the hull milling system: Set the hull milling roller spacing to 0.1~0.3 mm for hull milling to obtain hull milled wheat flour; (3) Milling system control: Set the milling roller spacing to 0.01~0.03 mm for milling to obtain milled wheat flour; (4) Flour combination: combine wheat flour from the bran milling process and wheat flour from the core milling process to obtain the medium glycemic index wheat flour.
[0007] Preferably, the wheat variety mentioned in step (1) is Zhongxinmai 998.
[0008] Preferably, the number of times the leather is ground in step (2) is 1-3 times.
[0009] Preferably, the number of times the core is ground in step (3) is 1-3 times.
[0010] Beneficial effects Compared with the prior art, the present invention has the following significant advantages: (1) Synergistic control mechanism: This invention establishes for the first time a synergistic control method for the distance between the bran mill and the core mill rollers, clarifying the division of labor mechanism in which the distance between the bran mill rollers dominates the bran stripping efficiency and starch release, while the distance between the core mill rollers dominates the degree of starch granule damage and digestibility.
[0011] (2) Targeted preparation of medium GI wheat flour: By reasonably widening the roller spacing (0.2~0.3 mm for bran mill and 0.02~0.03 mm for end mill), the integrity of starch granules can be preserved while ensuring the flour yield. The dietary fiber in the bran forms a physical barrier, which significantly delays starch digestion and reduces EGI. This is suitable for the development of medium glycemic index food ingredients.
[0012] (3) Differentiated utilization of flour path: It reveals the significant differences in starch and digestibility of wheat flour from different flour paths (1B, 2B, 3B, 1C, 2C, 3C), providing a theoretical basis for the separate collection and compounding of special wheat flour (such as medium GI flour and high starch retention flour).
[0013] (4) Precise and appropriate grinding: This invention practices the concept of "precise and appropriate grinding" to avoid starch damage and glycemic index increase caused by excessive grinding, while reducing unnecessary over-refining of endosperm, thereby improving the economic value of raw grains and the health attributes of end products. Attached Figure Description
[0014] Figure 1This is a diagram showing the damaged starch in wheat flour from different powdering paths under different spacings of the bran mill and core mill rollers according to the present invention. Figure 2 This is a graph showing the bran star index of wheat flour in each milling path under different spacings of the bran mill and the core mill rollers according to the present invention. Figure 3 This is a graph showing the starch hydrolysis rate of wheat flour in each powder path under different grinding roller spacing conditions according to the present invention. Figure 4 This is a graph showing the starch hydrolysis rate of wheat flour in each powder path under different concentric grinding roller spacing conditions according to the present invention. Figure 5 This is a bar chart showing the area under the hydrolysis curves (AUC) of wheat flour in different powder paths under different grinding roller spacing conditions according to the present invention. Figure 6 This is a bar chart showing the estimated glycemic index (EGI) of wheat flour for each grinding path under different grinding roller spacing conditions according to the present invention. Figure 7 This is a heatmap showing the correlation between the physicochemical properties of wheat flour (ash content, whiteness, damaged starch, falling value, etc.) and its in vitro glycemic properties. Detailed Implementation
[0015] A method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers, comprising the following steps: (1) Raw material pretreatment: Zhongxinmai 998 wheat variety (moisture content 11.40%, ash content 1.75%, bulk density 783g / L, thousand-grain weight 45.02g, hardness 67.95) was selected. After cleaning, stone removal and impurity removal, the wheat was moistened (wheat moisture was determined according to GB5009.3-2016, and the wheat was moistened according to NY / T1094.1-2006). The moisture content of the wheat was controlled at 14.5%, and the wheat was moistened at room temperature for 24 hours. (2) Adjustment of the hull milling system: Set the hull milling roller spacing to 0.1~0.3 mm and perform hull milling 1-3 times to obtain hull milled wheat flour; (3) Adjustment of the milling system: Set the milling roller spacing to 0.01~0.03 mm and perform milling 1-3 to obtain milled wheat flour; (4) Flour combination: combine wheat flour from the bran milling process and wheat flour from the core milling process to obtain the medium glycemic index wheat flour.
[0016] Specifically, the spacing between the leather grinding rollers is set to 0.1 mm, 0.2 mm, and 0.3 mm; the spacing between the core grinding rollers is set to 0.1 mm, 0.2 mm, and 0.3 mm.
[0017] By adjusting the grinding times of the bran mill and the core mill, wheat flour with different grinding paths was obtained, as shown in Table 1. Wheat flour with 6 different grinding paths was collected.
[0018] Table 1
[0019] The technical solution of the present invention will be further illustrated below through examples and comparative examples.
[0020] Example 1 Medium glycemic index wheat flour was prepared by setting the bran milling roller spacing to 0.1 mm and the core milling roller spacing to 0.02 mm (1 bran, 2 cores), with a bran milling time of 2409.5 s and a core milling time of 2319.5 s. The following measurements were taken: Wheat flour from Flour 1B had an ash content of 0.701%, a whiteness of 71.15, a damaged starch content of 19.59 UCD, a starch hydrolysis rate of 71.63% after 120 min, and an EGI of 74.00; wheat flour from Flour 2B had an ash content of 0.568%, a whiteness of 74.10, a damaged starch content of 18.81 UCD, a starch hydrolysis rate of 64.49% after 120 min, and an EGI of 71.46; wheat flour from Flour 3B had an ash content of 0.770%, a whiteness of 70.30, a damaged starch content of 20.69 UCD, a starch hydrolysis rate of 76.33% after 120 min, and an EGI of 77.34; wheat flour from Flour 1C had an ash content of 0.543%, a whiteness of 75.85, a damaged starch content of 21.44 UCD, and a starch hydrolysis rate of 78.12% after 120 min. The ash content of 2C-type wheat flour was 0.568%, the whiteness was 76.15, the damaged starch content was 22.73 UCD, the starch hydrolysis rate at 120 min was 84.96%, and the EGI was 81.23. The ash content of 3C-type wheat flour was 0.591%, the whiteness was 75.80, the damaged starch content was 23.07 UCD, the starch hydrolysis rate at 120 min was 85.27%, and the EGI was 81.18.
[0021] Example 2 Medium glycemic index wheat flour was prepared by setting the bran milling roller spacing to 0.2 mm and the core milling roller spacing to 0.02 mm (2 parts bran to 2 parts core), with a bran milling time of 2318 s and a core milling time of 2228 s. The wheat flour from the 1B feed route had an ash content of 0.685%, a whiteness of 71.20, a damaged starch content of 19.09 UCD, a starch hydrolysis rate of 68.47% at 120 min, and an EGI of 73.24; the wheat flour from the 2B feed route had an ash content of 0.544%, a whiteness of 74.65, a damaged starch content of 18.03 UCD, a starch hydrolysis rate of 61.56% at 120 min, and an EGI of 69.52; the wheat flour from the 3B feed route had an ash content of 0.717%, a whiteness of 71.05, a damaged starch content of 19.22 UCD, a starch hydrolysis rate of 72.76% at 120 min, and an EGI of 75.97; the wheat flour from the 1C feed route had an ash content of 0.479%, a whiteness of 76.65, a damaged starch content of 20.72 UCD, and an ash content of 0.685%, a whiteness of 71.20, a damaged starch content of 19.09 UCD, a starch hydrolysis rate of 68.47% at 120 min, and an EGI of 73.24; the wheat flour from the 1C feed route had an ash content of 0.479%, a whiteness of 76.65, a damaged starch content of 20.72 UCD, and an EGI of 73.24 at 120 min. The ash content of wheat flour with a 2C feed rate was 0.512%, whiteness was 76.75, damaged starch content was 21.52 UCD, and the starch hydrolysis rate at 120 min was 79.65%, with an EGI of 79.39. The ash content of wheat flour with a 3C feed rate was 0.512%, whiteness was 76.30, damaged starch content was 21.99 UCD, and the starch hydrolysis rate at 120 min was 79.72%, with an EGI of 79.72.
[0022] Example 3 Medium glycemic index wheat flour was prepared by setting the bran milling roller spacing to 0.3 mm and the core milling roller spacing to 0.02 mm (3 bran, 2 core), with a bran milling time of 2098 s and a core milling time of 2008 s. The wheat flour from the 1B feed route had an ash content of 0.708%, a whiteness of 70.65, a damaged starch content of 19.26 UCD, a starch hydrolysis rate of 60.38% at 120 min, and an EGI of 68.97. The wheat flour from the 2B feed route had an ash content of 0.561%, a whiteness of 74.65, a damaged starch content of 17.87 UCD, a starch hydrolysis rate of 58.60% at 120 min, and an EGI of 68.38. The wheat flour from the 3B feed route had an ash content of 0.715%, a whiteness of 71.25, a damaged starch content of 19.51 UCD, a starch hydrolysis rate of 71.70% at 120 min, and an EGI of 74.73. The wheat flour from the 1C feed route had an ash content of 0.457%, a whiteness of 77, a damaged starch content of 21.12 UCD, and a starch hydrolysis rate of 76.03% at 120 min. The ash content of 2C-type wheat flour was 0.471%, the whiteness was 77.05, the damaged starch content was 21.59 UCD, the starch hydrolysis rate at 120 min was 77.74%, and the EGI was 77.72. The ash content of 3C-type wheat flour was 0.489%, the whiteness was 76.65, the damaged starch content was 21.83 UCD, the starch hydrolysis rate at 120 min was 80.34%, and the EGI was 79.46.
[0023] Example 4 Medium glycemic index wheat flour was prepared by setting the bran milling roller spacing to 0.2 mm and the core milling roller spacing to 0.01 mm (2 bran, 1 core), with a bran milling time of 2392 s and a core milling time of 2302 s. The following measurements were taken: Wheat flour from 1B had an ash content of 0.670%, a whiteness of 71.40, a damaged starch content of 19.20 UCD, a starch hydrolysis rate of 68.50% after 120 min, and an EGI of 73.63; wheat flour from 2B had an ash content of 0.553%, a whiteness of 73.60, a damaged starch content of 17.88 UCD, a starch hydrolysis rate of 61.25% after 120 min, and an EGI of 70.15; wheat flour from 3B had an ash content of 0.728%, a whiteness of 70.40, a damaged starch content of 19.35 UCD, a starch hydrolysis rate of 72.95% after 120 min, and an EGI of 76.19; wheat flour from 1C had an ash content of 0.478%, a whiteness of 77.30, a damaged starch content of 21.74 UCD, and a starch hydrolysis rate of 68.50% after 120 min, and an EGI of 73.63 ...B had an ash content of 0.670%, a whiteness of 71.40, a damaged starch content of 19.20 UCD, a starch hydrolysis rate of 68.50% after 120 min, and an EGI of 73.63; wheat flour from 2B had an ash content of 0.553%, a whiteness of 73.60, a damaged starch content of 17.88 UCD, a The ash content of wheat flour with a 120-minute starch hydrolysis rate of 78.19% and an EGI of 79.44 was 79.44. The ash content of wheat flour with a 2C feed rate of 0.568%, a whiteness of 77.25, a damaged starch content of 23.85 UCD, a starch hydrolysis rate of 82.10% and an EGI of 80.70 was 120 min. The ash content of wheat flour with a 3C feed rate of 0.773%, a whiteness of 75.30, a damaged starch content of 27.08 UCD, a starch hydrolysis rate of 85.30% and an EGI of 82.00 was 120 min.
[0024] Example 5 Medium glycemic index wheat flour was prepared by setting the bran milling roller spacing to 0.2 mm and the core milling roller spacing to 0.03 mm (2 parts bran, 3 parts core), with a bran milling time of 2401 s and a core milling time of 2311 s. The following measurements were taken: Wheat flour from Flour 1B had an ash content of 0.687%, a whiteness of 71.75, a damaged starch content of 19.42 UCD, a starch hydrolysis rate of 67.86% after 120 min, and an EGI of 73.36; wheat flour from Flour 2B had an ash content of 0.559%, a whiteness of 73.70, a damaged starch content of 18.16 UCD, a starch hydrolysis rate of 60.11% after 120 min, and an EGI of 69.61; wheat flour from Flour 3B had an ash content of 0.746%, a whiteness of 71.00, a damaged starch content of 19.50 UCD, a starch hydrolysis rate of 70.15% after 120 min, and an EGI of 75.18; wheat flour from Flour 1C had an ash content of 0.497%, a whiteness of 76.25, a damaged starch content of 21.21 UCD, and a starch hydrolysis rate of 67.86% after 120 min, and an EGI of 73.36; wheat flour from Flour 2B had an ash content of 0.687%, a whiteness of 71.75, a damaged starch content of 19.42 UCD, a starch hydrolysis rate of 67.86% after 120 min, and an EGI of 73.36; wheat flour from Flour 3B had an ash content of 0.746%, a whiteness of 71.00, a damaged starch content of 19.50 UCD, a starch hydrolysis rate of 70.15% after 120 min, and an EGI of 75.18; wheat flour from Flour 1C had an ash content of 0.497%, a whiteness of 7 The ash content of wheat flour with a 120-minute starch hydrolysis rate of 75.83% and an EGI of 78.18 was 78.18. The ash content of wheat flour with a 2C flour profile was 0.527%, the whiteness was 76.00, the damaged starch content was 21.99 UCD, the ash content of wheat flour with a 120-minute starch hydrolysis rate of 79.88%, and the EGI was 79.85. The ash content of wheat flour with a 3C flour profile was 0.519%, the whiteness was 75.25, the damaged starch content was 21.77 UCD, the ash content of wheat flour with a 120-minute starch hydrolysis rate of 81.85%, and the EGI was 80.40.
[0025] As can be seen from the above embodiments, when the distance between the rind rollers is 0.3 mm and the distance between the core rollers is 0.02 mm, the resulting 2B flour has the lowest EGI, reaching 68.38.
[0026] Figure 1 This is a diagram showing the damaged starch in wheat flour from different powdering paths under different spacings of the bran mill and core mill rollers according to the present invention. Figure 2 This is a graph showing the bran star index of wheat flour in different milling paths under different spacings of the bran mill and the core mill rollers according to the present invention.
[0027] from Figure 1 , 2 The results showed that when the spacing between the bran mill rollers was changed (except for the 1B milling path), the whiteness of wheat flour in all other milling paths increased with increasing spacing, while the ash content decreased accordingly, and a significant negative correlation was observed between the two. However, when the spacing between the endosperm mill rollers was changed, the trends in whiteness and ash content were not significant, and the fluctuation range was small. These results indicate that the gradient control of the bran mill roller spacing mainly affects the peeling rate, thereby dominating the whiteness and ash content distribution of flour in each milling path. In the bran milling system, the roller spacing is mainly used for bran stripping, with relatively mild mechanical action and less damaged starch. In contrast, the endosperm milling system typically uses a smaller roller spacing to obtain fine endosperm particles, resulting in a significant increase in the damaged starch value of wheat flour in this milling path, which in turn leads to increased digestibility.
[0028] Wheat flour with different roller spacing combinations was prepared according to the methods in Examples 1-5. The in vitro digestibility characteristics of starch were determined using the Englyst method, and the area under the hydrolysis curve (AUC) and EGI were calculated. The table shows the total degree of starch hydrolysis throughout the in vitro process. The smaller the AUC value, the lower the overall starch digestion rate and the lower the corresponding EGI (estimated glycemic index).
[0029] Figure 3 This is a graph showing the starch hydrolysis rate of wheat flour in each powder path under different grinding roller spacing conditions according to the present invention. Figure 4 This is a graph showing the starch hydrolysis rate of wheat flour in each powder path under different concentric grinding roller spacing conditions according to the present invention. Figure 5 This is a bar chart showing the area under the hydrolysis curves (AUC) of wheat flour in different powder paths under different grinding roller spacing conditions according to the present invention. Figure 6 This is a bar chart showing the estimated glycemic index (EGI) of wheat flour for each grinding path under different grinding roller spacing conditions according to the present invention. Figure 7 This is a heatmap showing the correlation between the physicochemical properties of wheat flour (ash content, whiteness, damaged starch, falling value, etc.) and its in vitro glycemic properties.
[0030] Figure 3-7 The results show: (1) By Figure 3 , Figure 4 It can be seen that adjusting the spacing of the bran mill rollers increases the starch hydrolysis rate in each grinding path as the spacing decreases, with the most significant change observed in path 1B, where the hydrolysis rate decreased from 71.8% to 62.6% after 180 minutes. Adjusting the spacing of the core mill rollers also resulted in similar hydrolysis rates in paths 1C, 2C, and 3C, with paths 2C and 3C showing higher hydrolysis rates than path 1C. This may be because in the bran mill system, a smaller roller spacing helps to efficiently scrape off the bran, allowing for sufficient release of endosperm particles and maintaining a high starch content. As the grinding progresses further, the fine adjustment of the core mill roller spacing determines the degree of endosperm refinement. An excessively tight spacing leads to severe breakage of starch particles, resulting in a large amount of damaged starch, which significantly increases the starch hydrolysis rate and final digestibility.
[0031] (2) By Figure 5 It can be seen that the AUC of starch hydrolysis in the bran milling process (1B, 2B, 3B) is generally lower than that in the endosperm milling process (1C, 2C, 3C); and the AUC increases as the number of passes in the bran and endosperm mills increases. This may be because the bran mill in the earlier stages is responsible for stripping the bran and extracting more intact endosperm with a lower degree of starch damage; while the gap between the bran mill and the multi-stage endosperm mill in the later stages is smaller, and the endosperm is repeatedly ground to produce a large amount of damaged starch, which significantly increases the overall degree of starch hydrolysis.
[0032] (3) By Figure 6It is evident that the starch hydrolysis rate of wheat flour is positively correlated with the glycemic index (EGI). As the spacing between the bran and mill rollers decreases, the EGI values of wheat flour in each milling path gradually increase, indicating that the starch is increasingly broken down and more easily digested and absorbed. Furthermore, as the spacing between the core and mill rollers decreases, the EGI values of the core milling system (1C, 2C, 3C) also show an upward trend. These findings demonstrate that adjusting the roller spacing in the flour milling process can effectively delay starch digestion and control the increase in the estimated glycemic index.
[0033] (4) Figure 7 Correlation analysis showed a significant positive correlation between damaged starch and EGI (r>0.85, P<0.05), while crude fiber and bran particles showed a significant negative correlation with EGI (r<-0.70, P<0.05). Crude fiber and bran particles, as markers of reduced processing precision, exacerbate the deterioration of the gluten network with increased content, physically encapsulating starch granules and significantly inhibiting amylase activity, leading to a decrease in starch hydrolysis rate. Damaged starch, due to its disrupted internal crystal structure and increased specific surface area, is highly susceptible to hydrolysis by α-amylase, making it a key factor in improving in vitro digestion rates. Falling value primarily reflects starch viscosity characteristics and enzymatic potential; a lower falling value often indicates severe starch damage, accelerating the digestion process. By adjusting the balance of these indicators, the roller spacing can achieve precise control over the starch digestibility of each powder path.
[0034] The wheat flour preparation method provided by this invention can be directly implemented using existing wheat flour production lines (such as fully automatic experimental milling machines or industrial-scale milling machines) without requiring significant new equipment investment. By simply adjusting the distance between the bran mill and the core mill rollers, the processing precision and glycemic index of wheat flour with different powder paths can be directionally controlled. This method is suitable for the industrial production of specialty wheat flours (such as medium-GI wheat flour, high-fiber wheat flour, high-protein wheat flour, and refined wheat flour), and has broad application prospects and market value.
[0035] 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 medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select wheat varieties with a hardness index of 65~70, clean, remove stones and impurities, and then moisten the wheat. Control the moisture content of the wheat to 14.5%~15.5% and moisten the wheat at room temperature for 20-24 hours. (2) Adjustment of the hull milling system: Set the hull milling roller spacing to 0.1~0.3 mm for hull milling to obtain hull milled wheat flour; (3) Milling system control: Set the milling roller spacing to 0.01~0.03 mm for milling to obtain milled wheat flour; (4) Flour combination: combine wheat flour from the bran milling process and wheat flour from the core milling process to obtain the medium glycemic index wheat flour.
2. The method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers according to claim 1, characterized in that, The wheat variety mentioned in step (1) is Zhongxinmai 998.
3. The method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers according to claim 1, characterized in that, The number of times the leather is ground in step (2) is 1-3.
4. The method for preparing medium glycemic index wheat flour by adjusting the distance between the bran mill and the core mill rollers according to claim 1, characterized in that, The number of grinding cycles in step (3) is 1-3 times.