Preparation method of special high-gluten flour for high-fermentation gas-holding baking

Abstract

The invention discloses a preparation method of special high gluten flour for high-fermentation gas-holding baking, and relates to the technical field of flour processing.The preparation method comprises the steps that target wheat with the glutenin macropolymer GMP content not lower than 35% and the dough stabilization time not lower than 12 min is selected, and pretreated wheat grains are obtained through impurity removal, wheat wetting and standing; performing quantity-controlled peeling and first-stage tempering on the pretreated wheat grains, performing low-temperature peel grinding, flour cleaning and front-path core grinding, and separating to obtain a leavening response flour group and a middle wheat core material; the middle wheat core material is subjected to second-stage tempering and second-stage standing re-moistening, then is subjected to low-temperature amplitude-limiting core milling and fine screening, and is separated to obtain a gas-holding skeleton powder group; the flour blending proportion is determined according to the front-stage leavening index and the rear-stage gas holding index, the leavening response flour group and the gas holding skeleton flour group are mixed to obtain the special high-gluten flour for high-fermentation gas-holding baking, the front-stage leavening capacity and the rear-stage gas holding capacity can be strengthened respectively, collapse of the middle and rear stages of fermentation is reduced, and dough stability and baking suitability are improved.

Description

Technical Field

[0001] This invention relates to the field of flour processing technology, specifically to a method for preparing high-gluten flour for baking with high fermentation and gas retention properties. Background Technology

[0002] With the continuous development of baking preparation technology, the preparation technology of bread-specific high-gluten flour has gradually shifted from simply increasing the crude protein content to the comprehensive control of gluten quality, starch damage level, ash content, and dough fermentation rheological behavior.

[0003] Currently, most high-gluten flour production methods employ a whole-milling process. While this can improve gluten strength and purity, it makes it difficult to separate the flour suitable for initial leavening from the flour suitable for subsequent gas retention. As a result, the flour produced often exhibits problems such as rapid leavening but a tendency to collapse later, or strong gluten but slow leavening. Furthermore, existing technologies lack a process route that determines the flour blending ratio based on initial leavening performance and subsequent gas retention performance, making it difficult to balance rapid leavening and stable gas retention. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the technical solution of this invention is as follows: A method for preparing a high-gluten flour for baking with high fermentation and gas-holding capacity includes the following steps: S1. Select target wheat with a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 min, and remove impurities, moisten, and let stand to obtain pretreated wheat grains. S2. Controlled dehulling of pretreated wheat grains removes the outer bran layer and aleurone layer, while retaining the endosperm transition zone adjacent to the aleurone layer, resulting in dehulled wheat grains. The dehulled wheat grains undergo primary conditioning to create a milling state where the endosperm transition zone absorbs water and softens first, resulting in primary conditioned wheat grains. The primary conditioned wheat grains are then subjected to low-temperature bran milling, cleaning, and pre-processing core milling to separate the responsive flour group and the intermediate wheat core material. The responsive flour group is mainly composed of powder from the endosperm transition zone. S3. The intermediate wheat core material is subjected to secondary conditioning and secondary static rehydration to make the central endosperm in the intermediate wheat core material form a powder-making state, resulting in secondary conditioning wheat core material. The secondary conditioning wheat core material is subjected to low-temperature limited-amplitude core milling and fine sieving to separate the gas-holding skeleton powder group, which is mainly composed of powder from the central endosperm. S4. Measure the water addition and dough formation speed and the initial fermentation height growth rate of the leavening response powder group to obtain the first-stage leavening index; measure the dough stability time and volume retention rate of the gas-holding framework powder group to obtain the second-stage gas-holding index; determine the powder ratio based on the first-stage leavening index and the second-stage gas-holding index; mix the leavening response powder group and the gas-holding framework powder group according to the powder ratio to obtain high-gluten flour for baking with high fermentation gas-holding capacity.

[0005] Furthermore, in S2, controlled peeling is carried out layer by layer along the outer periphery of the pretreated wheat grain until the endosperm transition zone is continuously exposed on the surface of the pretreated wheat grain, and peeling is stopped when the continuous internal core structure is not damaged, thus obtaining peeled wheat grains. The amount of hulling should be controlled between 3.5% and 8.5% of the pretreated wheat grain mass.

[0006] Furthermore, in S2, the first-stage conditioning includes a first-stage water addition and a second-stage water addition; After adding water in the first stage, adjust the moisture content of the hulled wheat grains to 15.5%–16.2% and let them stand for 1–3 hours. After adding water in the second stage, the moisture content of the hulled wheat grains is adjusted to 16.2%–17.0%, and then left to stand for 1–3 hours. After primary conditioning, the softening degree of the endosperm transition zone is higher than that of the central endosperm.

[0007] Furthermore, in S2, the primary conditioned wheat grains undergo low-temperature bran milling, purifying, and pre-milling in sequence; The temperature of the grinding rollers in the low-temperature grinding mill is controlled below 30℃, and the grinding gap of the preceding grinding mill is controlled between 1.2mm and 1.5mm. The powder flow is separated from the adjacent endosperm transition zone using a 36-mesh sieve; The speed of the front end mill is controlled between 550 rpm and 650 rpm; The separated adjacent endosperm transition zone powder flows are merged to form an initiation response powder group, while the remaining continuous wheat core portion constitutes the intermediate wheat core material.

[0008] Furthermore, in S3, the secondary conditioning and secondary settling rehydration are carried out on intermediate wheat core materials; After adding water, the moisture content of the middle wheat core material is adjusted to 14.0% to 15.5%; then it is left to stand for 4 to 10 hours to allow the moisture to migrate from the outer periphery of the middle wheat core material to the central endosperm. After two-stage conditioning and two-stage settling and rehydration, the central endosperm is in a milling state, resulting in secondary-conditioned wheat core material.

[0009] Furthermore, in S3, the secondary conditioned wheat core material undergoes low-temperature limited-amplitude milling and fine sieving in sequence; The temperature of the grinding rollers in the low-temperature limiting center mill is controlled below 30℃; During fine sieving, ash content and particle size range are used as sieving boundaries. Coarse powder streams with ash content higher than 0.45% are sieved out, while central endosperm powder streams with particle size within the preset range and ash content not higher than 0.45% are retained. The retained central endosperm powder streams are then aggregated to form an air-holding skeleton powder group. The ash and damaged starch content of the gas-holding skeleton powder group were lower than those of the leavening response powder group, and the GMP retention level of glutenin macropolymers in the gas-holding skeleton powder group was higher than that in the leavening response powder group.

[0010] Furthermore, in S4, the powder ratio is determined in two steps; First, use the air-holding skeleton powder group as the base powder group, and gradually add the ignition response powder group to determine the minimum amount to meet the front-end ignition index; And based on the minimum addition amount, adjust the addition amount of the gas-holding skeleton powder group to determine the minimum addition amount that meets the gas-holding index of the later stage; The amount of the initiating response powder group is 20% to 45% of the total mass of the finished powder, and the amount of the gas-holding skeleton powder group is 55% to 80% of the total mass of the finished powder.

[0011] Furthermore, in S4, the starter-response powder group and the gas-holding skeleton powder group are mixed according to the powder ratio, and then homogenized and allowed to stand for homogenization to obtain high-gluten flour for baking with high fermentation and gas-holding capacity. The homogenization time should be controlled between 10 min and 40 min. After homogenization and static homogenization, the initiating response powder group and the gas-holding skeleton powder group are uniformly dispersed without changing their respective source structures.

[0012] The beneficial effects of this invention are as follows: 1. By controlling the amount of peeling, primary conditioning, low-temperature peel milling, powder purification, and front-end milling, the endosperm transition zone powder flow of adjacent aleurone layers is separated to form a leavening-responsive powder group. After this treatment, the front end is more likely to form a powder base with fast water absorption, fast agglomeration, and fast initial leavening response. Compared with the whole-process milling method, it can reduce the problems of slow leavening and insufficient initial expansion in the front end.

[0013] 2. By performing two-stage conditioning, two-stage resting and rehydration, low-temperature limited-amplitude milling, and fine sieving on the central wheat core material, the central endosperm powder flow is further separated to form an air-holding skeletal powder group. After this treatment, the skeletal structure of the central endosperm is more fully preserved, and the ash and damaged starch content is lower. It is easier to maintain the stability and volume retention of the dough in the later stages. Compared with ordinary milling and uniform sieving, it can reduce the problems of collapse and coarsening of the texture in the later stages of fermentation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the steps of a method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to the present invention. Figure 2 This is a diagram illustrating the formation process of the gas-holding skeleton powder group of the present invention; Figure 3 This is a diagram showing the correspondence between the sources and functions of the dual-powder group in this invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1 Please see Figure 1 , Figure 2 and Figure 3 This invention provides a method for preparing high-gluten flour for baking with high fermentation and gas retention properties, comprising the following steps: S1. Select target wheat with a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 min, and remove impurities, moisten, and let stand to obtain pretreated wheat grains. S2. Controlled dehulling of pretreated wheat grains removes the outer bran layer and aleurone layer, while retaining the endosperm transition zone adjacent to the aleurone layer, resulting in dehulled wheat grains. The dehulled wheat grains undergo primary conditioning to create a milling state where the endosperm transition zone absorbs water and softens first, resulting in primary conditioned wheat grains. The primary conditioned wheat grains are then subjected to low-temperature bran milling, cleaning, and pre-processing core milling to separate the responsive flour group and the intermediate wheat core material. The responsive flour group is mainly composed of powder from the endosperm transition zone. S3. The intermediate wheat core material is subjected to secondary conditioning and secondary static rehydration to make the central endosperm in the intermediate wheat core material form a powder-making state, resulting in secondary conditioning wheat core material. The secondary conditioning wheat core material is subjected to low-temperature limited-amplitude core milling and fine sieving to separate the gas-holding skeleton powder group, which is mainly composed of powder from the central endosperm. S4. Measure the water addition and dough formation speed and the initial fermentation height growth rate of the leavening response powder group to obtain the first-stage leavening index; measure the dough stability time and volume retention rate of the gas-holding framework powder group to obtain the second-stage gas-holding index; determine the powder ratio based on the first-stage leavening index and the second-stage gas-holding index; mix the leavening response powder group and the gas-holding framework powder group according to the powder ratio to obtain high-gluten flour for baking with high fermentation gas-holding capacity.

[0017] In this embodiment, the same batch of hard winter wheat was selected as the raw material.

[0018] This embodiment selects the same batch of hard winter wheat as raw material because high-gluten flour for baking with high fermentation and gas retention is mainly used in baking scenarios with high water absorption, long fermentation and high specific volume. Such scenarios have high requirements for the protein skeleton and dough stability of the raw wheat.

[0019] Hard winter wheat, compared to ordinary soft wheat, typically has a higher protein level and stronger gluten structure, making it more suitable as a raw material source for the step-by-step milling process in this embodiment.

[0020] However, selecting only hard winter wheat is not enough to guarantee that the process in this embodiment can stably form the starter-response powder group and the gas-holding skeleton powder group. Therefore, it is necessary to further screen target wheat with a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 minutes in the same batch of hard winter wheat.

[0021] First, the target wheat is treated to remove impurities, such as stones, metal impurities, chaff, and broken grains. Subsequently, water was added at 2.2% of the target wheat mass to moisten the wheat, and the grains were left to stand at 22℃ for 8 hours to obtain pretreated wheat grains.

[0022] The pretreated wheat grains were dehulled in a controlled manner, with the dehulling amount controlled at 5.6%. The dehulling endpoint was achieved when the endosperm transition zone was continuously exposed on the surface of the pretreated wheat grains and the internal wheat cob remained continuous and intact.

[0023] After controlled peeling is completed, the outer bran layer and aleurone layer of the pretreated wheat grain are effectively peeled off, while the endosperm transition zone adjacent to the aleurone layer is preserved, resulting in peeled wheat grains.

[0024] The hulled wheat grains were then subjected to primary conditioning.

[0025] The first stage of conditioning is completed in two stages. After the first addition of water, the moisture content of the hulled wheat grains is adjusted to 15.8%, and then left to stand for 2 hours. After the second addition of water, the moisture content of the hulled wheat grains is adjusted to 16.6%, and then left to stand for another 2 hours.

[0026] After primary conditioning, the endosperm transition zone absorbs water and softens before the central endosperm, resulting in primary conditioned wheat grains.

[0027] The first-grade conditioned wheat grains are sequentially fed into the low-temperature hull milling process, the cleaning process, and the pre-processing core milling process.

[0028] The temperature of the grinding rollers in the low-temperature grinding process is controlled at 28℃, the distance between the grinding rollers in the preceding grinding process is controlled at 1.3mm, and the rotation speed of the center grinding process in the preceding grinding process is controlled at 600rpm.

[0029] The cleaning process separates the flour streams adjacent to the endosperm transition zone and merges the separated flour streams to form an ignition response flour group; the continuous core portion of the wheat kernels retained after the ignition response flour group is separated forms the intermediate core material.

[0030] Next, the intermediate wheat core material is subjected to secondary conditioning and secondary settling and rehydration.

[0031] After adding water, the moisture content of the middle wheat core material is adjusted to 14.8%. It is then left to stand at 22℃ for 6 hours to allow moisture to migrate from the outer periphery of the middle wheat core material to the central endosperm. Once the central endosperm is formed, it is in a water-absorbing and low-brittle milling state, thus obtaining the secondary conditioned wheat core material.

[0032] The secondary conditioned wheat core material is then fed into the low-temperature limited-amplitude core milling process and the fine screening process in sequence. The temperature of the grinding rollers in the low-temperature limited-amplitude core milling process is controlled at 27°C. The fine screening process removes coarse powder with high ash content, retains fine powder from the central endosperm, and merges the retained fine powder from the central endosperm to form an air-holding skeleton powder group.

[0033] After the separation of the two powder groups was completed, the water addition and agglomeration rate and the growth rate of fermentation height in the initial stage of fermentation of the fermentation response powder group were measured to obtain the initial fermentation index. The dough stability time and volume retention rate in the later stage of fermentation were measured separately for the gas-holding skeletal powder group to obtain the gas-holding index in the later stage.

[0034] It should be noted that the initial leavening index and the subsequent gas-holding index were measured under the same test conditions. Specifically, the leavening response powder group and the gas-holding skeleton powder group were sampled according to the 14% standard moisture basis and equilibrated under the same room temperature conditions. The dough formation rate of the leavening response powder group and the dough stability time of the gas-holding skeleton powder group were measured using a farinograph.

[0035] The time required from the start of water addition until the powder curve first reaches 500 FU is recorded as the dough formation time. The reciprocal of the dough formation time represents the speed of water addition and dough formation. The time interval between the first intersection of the upper edge of the powder curve with the 500 FU line and the departure from the 500 FU line is recorded as the dough stabilization time.

[0036] The growth rate of fermentation height in the initial fermentation stage of the starter-response powder group and the volume retention rate in the later fermentation stage of the gas-holding skeleton powder group were measured using a fermentation rheometer. After testing the dough of each powder group according to a unified formula and dough formation standard, the dough was loaded into the fermentation rheometer. The dough development height curve was continuously recorded under the conditions of 30℃ and 85% relative humidity. The initial height at the end of loading was recorded as H0, and the dough height 30 minutes after the start of fermentation was recorded as H30.

[0037] The initial fermentation height growth rate is calculated as [(H30-H0) / H0]×100%.

[0038] The maximum dough height during fermentation is denoted as Hm, and the dough height at 180 minutes of fermentation is denoted as H180.

[0039] The volume retention rate of the later stage of fermentation is calculated as (H180 / Hm)×100%.

[0040] The above-mentioned unified measurement method can be used to characterize the responsiveness of the starter powder group in the early stage of dough kneading and the early stage of fermentation, as well as the skeletal bearing capacity and volume retention capacity of the gas-holding skeleton powder group in the middle and later stages of fermentation.

[0041] The flour ratio was determined based on the initial rise index and the subsequent gas retention index. Finally, the rise response flour group and the gas retention framework flour group were mixed at a mass ratio of 35:65. After mixing, the mixture was allowed to stand and homogenize for 15 minutes to obtain high-gluten flour for baking with high fermentation and gas retention properties.

[0042] To verify the effectiveness of this embodiment, comparative examples 1, 2, and 3 were also set up.

[0043] Comparative Example 1 used the same batch of target wheat that was moistened and then directly processed at low temperature without controlled peeling, separation of two flour groups, or grouping of flour; Comparative Example 2 uses the same controlled peeling and first-stage conditioning as Example 1.1, but after separating the ignition response powder group, it does not continue to form the gas-holding skeleton powder group, but directly remixes the remaining powder stream with the ignition response powder group; Comparative Example 3 uses regular high-gluten flour and adds conventional compound improvers for compensation.

[0044] All test subjects underwent standardized baking tests using the same dough kneading procedure, the same amount of water added, the same amount of yeast added, and the same proofing conditions.

[0045] Table 1: Performance test results of the powder formulation systems of the initiation response powder group and the gas-holding skeleton powder group and the comparative sample. Parameter name / unit Example 1.1 - Two-component stepwise powder preparation sample Comparative Example 1 - Overall Low-Temperature Powdering Sample Comparative Example 2 - Remixed Samples of Powder Groups That Only Formed an Initiation Response Comparative Example 3 - Ordinary high-gluten flour + improver sample Initiation response powder formulation ratio / % 35 0 22 0 Gas-holding skeleton powder composition ratio / % 65 0 0 0 Time to form dough with water / seconds 82 109 88 96 Initial fermentation height growth rate / % 31.5 22.4 29.8 27.1 Dough stability time / min 14.8 12.7 11.9 13.4 Volume retention rate in the later stage of fermentation / % 93.6 84.2 78.9 86.8 Bread volume (mL / g) 5.62 4.91 5.08 5.17 Pore ​​uniformity score / points 8.7 6.9 6.4 7.3 Damaged starch content / % 4.3 5.8 5.1 5.6 Ash content of finished product / % 0.43 0.48 0.46 0.47 In Table 1, the bread specific volume represents the volume value corresponding to a unit mass of bread. It is used to reflect the overall expansion and internal fluffiness of bread after baking. During the measurement, the bread sample is cooled to room temperature, and the total volume of the bread is measured by the rapeseed replacement method or a volume measuring instrument. The total volume of the bread is then divided by the bread mass to obtain the bread specific volume, which is in mL / g. The higher the bread specific volume value, the greater the effective expansion space formed by the bread during the baking process. The volume retention rate in the later stage of fermentation represents the proportion of the dough volume that remains after reaching its maximum expansion state during fermentation and until the end of the later stage of fermentation. It is used to reflect the dough's gas retention capacity and skeletal stability during the later stage of fermentation. During the measurement, the dough development height curve is continuously recorded using a fermentation rheometer. The maximum dough height during the fermentation process is recorded as Hm, and the dough height at 180 min of fermentation is recorded as H180. The volume retention rate in the later stage of fermentation is calculated as (H180 / Hm)×100%. The higher the value, the less likely the dough is to collapse in the later stage. The uniformity score of the air pockets indicates the uniformity of the distribution of air pockets inside the bread and the continuity of the pore walls. When evaluating, the bread is cut open along the middle and the distribution of air pocket size, the consistency of pore shape, the continuity of pore walls, and the concentration or collapse of large pores in the cross-section are observed. The bread is scored according to the preset sensory evaluation criteria, with a full score of 10 points. The higher the score, the finer and more uniform the internal structure. Damaged starch content indicates the proportion of starch whose structure is damaged due to mechanical shearing and extrusion during the milling process. Damaged starch content is used to reflect the degree of damage to the powder during the milling process. It can be quantitatively analyzed by enzymatic method or near-infrared method. The result is expressed as a mass percentage. The higher the damaged starch content, the more obvious the mechanical damage to the powder during the milling process, and the easier it is for subsequent water absorption and fermentation reactions to become unbalanced. Finished product ash content represents the percentage of inorganic matter remaining after high-gluten baking flour with high fermentation and gas-holding capacity is burned at high temperature. It is used to reflect the degree of mixing of outer layer structure and refining degree in finished flour. During the test, the flour is burned and the mass of the residue is weighed according to the conventional method for determining flour ash content. The result is expressed as a percentage. The lower the finished product ash content value, the less high-ash components such as bran layer and aleurone layer are mixed in the finished flour, which is more conducive to maintaining the color, purity and subsequent baking stability of the flour.

[0046] As can be seen from Table 1, Example 1.1 shows significant advantages in both initial ignition performance and subsequent gas holding performance.

[0047] The water addition and dough formation time in Example 1.1 was 82s, which was significantly shorter than 109s in Comparative Example 1, 88s in Comparative Example 2, and 96s in Comparative Example 3. This indicates that the leavening response powder group formed by separation in S2 can significantly improve the water absorption response speed of flour in the initial stage of kneading.

[0048] The initial fermentation height growth rate of Example 1.1 reached 31.5%, which was significantly higher than that of Comparative Examples 1, 2 and 3, indicating that the fermentation response powder group not only improved the water absorption and agglomeration speed, but also improved the gas expansion establishment speed in the initial fermentation stage.

[0049] On the other hand, the dough stability time of Example 1.1 reached 14.8 min, and the volume retention rate in the later stage of fermentation reached 93.6%, both of which were significantly better than those of Comparative Examples 1, 2 and 3. This indicates that the gas-holding skeletal powder group formed by S3 can provide stronger skeletal bearing capacity and higher volume retention capacity in the later stage of fermentation.

[0050] In particular, in Comparative Example 2, although an responsive starter powder group was formed, the gas-holding skeletal powder group was not formed. Instead, the remaining powder stream was directly remixed. As a result, the dough stabilization time was only 11.9 min, and the volume retention rate in the later stage of fermentation was only 78.9%. This result shows that the advantage of this embodiment does not come simply from controlled peeling or primary conditioning, nor simply from the responsive starter powder group, but from the stepwise formation and powder coupling of the responsive starter powder group and the gas-holding skeletal powder group.

[0051] Furthermore, considering the bread volume and porosity scores, Example 1 achieved 5.62 mL / g and 8.7 points respectively, indicating that this example not only enables the dough to rise faster and retain gas more stably, but also improves the final texture of baked goods.

[0052] Regarding the damaged starch content, Example 1.1 had only 4.3%, which was lower than the three comparative groups, indicating that the low-temperature limited-amplitude milling and fine sieving in S3 are beneficial to preserving the complete skeletal structure of the central endosperm powder flow.

[0053] As can be seen from the data in Table 1, this embodiment, by dividing the same batch of target wheat into a starter-response powder group and an air-holding skeleton powder group in stages, and then constraining the powder ratio according to the starter index and the air-holding index, enables the finished flour to simultaneously obtain faster starter-response ability and stronger air-holding ability in the later stage, thereby effectively overcoming the shortcomings of existing overall milling routes where it is difficult to balance starter-response ability in the early stage and air-holding ability in the later stage.

[0054] Example 2 Please refer to Figure 1 and Figure 3 Specifically: In S2, controlled peeling is carried out layer by layer along the outer periphery of the pretreated wheat grain until the endosperm transition zone is continuously exposed on the surface of the pretreated wheat grain, and peeling is stopped without damaging the continuous internal core structure, thus obtaining peeled wheat grains. The amount of hulling should be controlled between 3.5% and 8.5% of the pretreated wheat grain mass.

[0055] In S2, the first stage of conditioning includes the first stage of water addition and the second stage of water addition; After adding water in the first stage, adjust the moisture content of the hulled wheat grains to 15.5%–16.2% and let them stand for 1–3 hours. After adding water in the second stage, the moisture content of the hulled wheat grains is adjusted to 16.2%–17.0%, and then left to stand for 1–3 hours. After primary conditioning, the softening degree of the endosperm transition zone is higher than that of the central endosperm.

[0056] Specifically, the degree of softening is as follows: under the same compression test conditions, the compressive hardness of the endosperm transition zone is lower than that of the central endosperm, the compressive deformation is higher than that of the central endosperm, and the peak burst load is lower than that of the central endosperm. This indicates that the endosperm transition zone has already completed water absorption and softening before the central endosperm after primary conditioning, and is more likely to be preferentially released during subsequent low-temperature skin milling and front-path core milling.

[0057] In S2, the primary conditioned wheat grains undergo low-temperature bran milling, flour cleaning, and pre-milling in sequence; The temperature of the grinding rollers in the low-temperature grinding mill is controlled below 30℃, and the grinding gap of the preceding grinding mill is controlled between 1.2mm and 1.5mm. The powder flow is separated from the adjacent endosperm transition zone using a 36-mesh sieve; The speed of the front end mill is controlled between 550 rpm and 650 rpm; The separated adjacent endosperm transition zone powder flows are merged to form an initiation response powder group, while the remaining continuous wheat core portion constitutes the intermediate wheat core material.

[0058] In this embodiment, the same batch of hard winter wheat as in Example 1 was selected as the raw material.

[0059] Testing revealed that the batch of raw wheat contained 15.1% protein, 36.8% wet gluten, and 36.4% glutenin macropolymer GMP content. The dough stability time corresponding to the raw grain was 12.6 minutes, which meets the raw material requirements for high-gluten flour for baking with high fermentation and gas retention.

[0060] First, the raw wheat is treated to remove impurities such as stones, light impurities, metal impurities, and broken grains. Then, water is added at 2.2% of the raw wheat mass to moisten the wheat, and it is left to stand at 22℃ for 8 hours to obtain pretreated wheat grains.

[0061] First, controlled-quantity dehulling is carried out on the pretreated wheat grains. The controlled-quantity dehulling is carried out layer by layer along the outer periphery of the pretreated wheat grains. During the dehulling process, the surface condition is observed every 0.5% of the dehulled amount. Dehulling is stopped when the endosperm transition zone is continuously exposed on the surface of the pretreated wheat grains and the internal core structure is still maintained when cut open for observation.

[0062] Ultimately, the amount of hulled wheat was controlled at 5.6% of the pre-treated wheat grain mass, thus obtaining hulled wheat grains.

[0063] This step does not only reduce the outer high-ash content, but also transforms the endosperm transition zone from being covered by the bran and aleurone layers to being able to directly accept subsequent conditioning and diversion. At the same time, it avoids excessive peeling that could cause premature breakage of the inner wheat core, thus preserving the foundation for the subsequent formation of the responsive flour group and the middle wheat core material.

[0064] After obtaining the hulled wheat kernels, a first-stage conditioning process is carried out. The first-stage conditioning is completed in two stages. After the first addition of water, the moisture content of the hulled wheat kernels is adjusted to 15.8%, and then left to stand for 2 hours. After the second addition of water, the moisture content of the hulled wheat kernels is adjusted to 16.6%, and then left to stand for another 2 hours to obtain the first-stage conditioned wheat kernels.

[0065] It should be noted that the two water additions in the first stage of conditioning are not based on empirical watering, but rather on quantitative conditioning based on the initial moisture content of the hulled wheat grains.

[0066] Specifically, the initial moisture content of the hulled wheat grains is first measured to obtain the initial moisture content W0 of the hulled wheat grains; then, the amount of water added in the first stage and the amount of water added in the second stage are calculated based on the target moisture content W1 of the first conditioning and the target moisture content W2 of the second conditioning, respectively.

[0067] Let the mass of the hulled wheat grains be M. The amount of water added in the first stage is calculated as M×(W1-W0) / (1-W1), where W1 is taken as 15.5%~16.2%. After the first stage of water addition is completed, the hulled wheat grains are sent into the mixing device and stirred for 8 to 15 minutes to ensure that the water is evenly attached to the surface of the hulled wheat grains. Then, let it stand for 1 to 3 hours to allow the endosperm transition zone to absorb water preferentially.

[0068] After the settling period, the actual moisture content of the hulled wheat grains was measured again to obtain the actual moisture content W1' after the first stage of conditioning. Then, calculate the amount of water added in the second stage according to the target moisture content W2 in the second stage. The amount of water added in the second stage is calculated as (M + amount of water added in the first stage) × (W2 - W1') / (1 - W2), where W2 is taken as 16.2% to 17.0%.

[0069] During the second stage of water addition, water is added in several stages using a misting spray method. After each addition, the mixture is stirred and stirred for 5 to 10 minutes to prevent moisture from accumulating on the surface of local wheat grains. After the second stage of water addition is completed, the mixture is left to stand for 1 to 3 hours to allow the moisture to continue to diffuse from the endosperm transition zone to the center of the endosperm.

[0070] After the two water additions, the moisture content of the first-stage conditioned wheat grains was retested using a rapid moisture analyzer, and the deviation between the measured value and the target value was controlled to be no more than ±0.2%.

[0071] By adopting the above-mentioned method of adding water twice in quantitative amounts and allowing the grains to stand in sections, it is possible to avoid excessive water addition at one time, which would cause the surface of the peeled wheat grains to become too wet and the outer layer to stick together. On the other hand, it is possible to allow the endosperm transition zone to form a higher degree of softening before the central endosperm, thereby providing a stable layer difference basis for the subsequent low-temperature hull milling, powder cleaning, and front-end core milling directional separation of the responsive powder group in S2.

[0072] The purpose of the two-stage water addition and two-stage resting is to allow the endosperm transition zone of the adjacent aleurone layer to absorb water and soften before the central endosperm, thereby creating a more obvious softening difference within the same grain, rather than allowing the entire grain to soften simultaneously.

[0073] After primary conditioning is completed, slices of primary conditioning wheat grains are observed and their hardness is compared. It can be confirmed that the softening degree of the endosperm transition zone is higher than that of the central endosperm.

[0074] The primary conditioned wheat grains are then sequentially fed into the low-temperature endosperm milling process, the cleaning process, and the pre-endosperm milling process. In the low-temperature endosperm milling process, the mill roller temperature is controlled at 28℃, the pre-endosperm milling gap is controlled at 1.3mm, and the pre-endosperm milling speed is controlled at 600rpm. The cleaning process uses a 36-mesh sieve to separate the flour flow from the adjacent endosperm transition zone.

[0075] After low-temperature endosperm milling, cleaning, and front-end milling, the separated adjacent endosperm transition zone powder streams are merged to form the priming response powder group; at the same time, the remaining continuous wheat core portion constitutes the intermediate wheat core material.

[0076] In this embodiment, the initiation response powder group mainly undertakes the functions of initial water absorption and agglomeration and rapid response in the initial stage of powder mixing, while the middle wheat core material serves as the raw material basis for the subsequent formation of the gas-holding skeleton powder group.

[0077] To illustrate the role of each technical feature in this embodiment, four comparative examples are also provided.

[0078] Comparative Example 1.2 did not undergo controlled peeling; after moistening, it was directly subjected to single-stage conditioning and then entered the low-temperature hull mill and the pre-processing core mill. Compared with ratio 2.2, the amount of peeling was controlled, but the first-stage conditioning only adopted a single-stage water addition and a single-stage settling, and did not adopt a two-stage first-stage conditioning; Compared with ratio 3.2, the amount of peeling and two-stage first-stage conditioning were carried out, but the powder cleaning process did not use a 36-mesh sieve for diversion, but directly merged into the front core mill; Comparative Example 4.2 adopted an excessive peeling route, increasing the peeling amount to 9.2%, while keeping the other conditions the same as in Example 2.1.

[0079] For each test subject, the extraction rate of the starter response powder group, the continuous retention rate of the intermediate wheat core material, the time for the starter response powder group to form a dough after adding water, the growth rate of the fermentation height in the initial stage of startering, the ash content of the starter response powder group, the damaged starch content of the starter response powder group, and the difference in softening between the endosperm transition zone and the central endosperm after primary conditioning were measured.

[0080] The time for water to form a dough was measured using a farinograph. The time required from the start of water addition until the farinograph curve first reached 500 FU was recorded as the water addition time for dough formation. The growth rate of the fermentation height in the initial fermentation stage was measured using a fermentation rheometer. The initial height of the dough when the sample was filled was recorded as H0, and the height of the dough after 30 minutes of fermentation was recorded as H30. The growth rate was calculated as [(H30-H0) / H0]×100%. The extraction rate of the ignition response powder group was calculated as the ratio of the mass of the ignition response powder group to the mass of the primary conditioned wheat grains fed into the feed. The continuous retention rate of the intermediate wheat core material is calculated as the percentage of the wheat core mass that retains a complete and continuous structure relative to the theoretically retained wheat core mass. The difference in softening between the endosperm transition zone and the central endosperm was determined by a slice compression test. The result was calculated by subtracting the central endosperm compression deformation from the endosperm transition zone compression deformation, dividing by the central endosperm compression deformation, and then converting the result into a percentage.

[0081] The above-described process and testing conditions can adequately reflect the material stratification effect and functional powder group formation effect in the actual powder making process of this embodiment.

[0082] Table 2: Experimental results of the effects of controlled peeling, two-stage primary conditioning, and powder separation on the formation of the starter powder group. Parameter name / unit Example 2.1 - Controlled peeling + two-stage primary conditioning + 36-mesh powder sample Comparative Example 1.2 - Uncontrolled Peeling Sample Comparative Example 2.2 - Single-stage primary conditioning sample Comparative Example 3.2 - Samples not treated with 36-mesh powder Comparative Example 4.2 - Excessive Peeling Sample Controlled peeling amount / % 5.6 0 5.5 5.6 9.2 Initiation response powder extraction rate / % 24.9 15.8 20.9 19.1 22 Continuous retention rate of intermediate wheat core material / % 91.6 86.7 88.5 89.2 73.6 Time to form dough with water in the starter powder group / seconds 82 109 89 93 84 Initial fermentation height growth rate / % 31.5 22.4 27.5 26 28.2 Ash content of the responsive powder group / % 0.46 0.58 0.51 0.54 0.49 Initiation response powder group damaged starch content / % 4.4 6 5.3 5.6 4.9 Difference in softening between the endosperm transition zone and the central endosperm after primary conditioning / % 18.8 7.5 11.4 18.1 17.3 The controlled-quantity peeling amount in Table 2 represents the percentage of the outer layer tissue removed from the periphery of the pretreated wheat grain during the controlled-quantity peeling process, relative to the original mass of the pretreated wheat grain. This reflects the degree of peeling of the bran layer and aleurone layer by the controlled-quantity peeling process. The extraction rate of the responsive powder group represents the percentage of the mass of the responsive powder group finally formed after low-temperature endosperm milling, cleaning and front-end milling, relative to the mass of the primary conditioned wheat grains. It is used to reflect the degree to which the powder flow in the adjacent endosperm transition zone is effectively separated and transformed into functional powder groups. The intermediate wheat core material continuity retention rate represents the percentage of intermediate wheat core material mass that still maintains a continuous wheat core structure after the initial response flour separation, relative to the theoretically retained wheat core mass. It is used to reflect the degree of retention of subsequent wheat core integrity by controlled peeling and the pre-milling process. The time for the responsive starter powder to form a dough after adding water indicates the time required for the responsive starter powder to reach 500 FU for the first time in the farinograph from the start of water addition. It is used to reflect the water absorption response speed of the responsive starter powder in the initial stage of dough kneading. The smaller the value, the faster the water absorption and dough formation. The initial fermentation height growth rate represents the relative increase in dough height during the initial fermentation stage under uniform formula and fermentation conditions. The initial height at the completion of sample loading is recorded as H0, and the dough height after 30 minutes of fermentation is recorded as H30. The result is calculated as [(H30-H0) / H0]×100% to reflect the volume build-up ability of the initial fermentation stage of the starter response powder group. The ash content of the ignition response powder group indicates the percentage of inorganic matter remaining in the sample mass after ignition response powder group is burned. It is used to reflect the degree of mixing of the outer high ash group. The lower the value, the higher the degree of refinement of the ignition response powder group. The damaged starch content of the responsive powder group indicates the proportion of starch in the responsive powder group that has suffered structural damage due to mechanical grinding. It is used to reflect the degree of starch damage during the upstream milling process. The lower the value, the less mechanical damage the powder has suffered during the milling process. The softening difference between the endosperm transition zone and the central endosperm after primary conditioning indicates the degree of difference in softening between the endosperm transition zone and the central endosperm after primary conditioning. It can be obtained through slice compression test or hardness test. It is used to reflect whether the two primary conditioning stages have effectively established the layer softening difference. The larger the value, the more obvious the degree of softening of the endosperm transition zone before the central endosperm, and the more conducive it is to the subsequent directional separation of the responsive powder group.

[0083] As can be seen from Table 2, Example 2.1 is significantly better than the comparative examples in both the quality of the initiation response powder group formation and the quality of the retention of the intermediate wheat core material.

[0084] First, in terms of the extraction rate of the initiating response powder group, Example 2.1 reached 24.9%, which is significantly higher than the 15.8% of Comparative Example 1.2, the 20.9% of Comparative Example 2.2, and the 19.1% of Comparative Example 3.2.

[0085] This result indicates that controlled peeling, two-stage primary conditioning, and 36-mesh powder separation are not independent routine actions, but rather work together in the same process chain to allow the powder flow in the adjacent endosperm transition zone to be more fully separated and merged to form the aeration response powder group.

[0086] Comparative Example 1.2 did not undergo controlled dehulling, and the outer bran layer and aleurone layer still covered the surface of the pretreated wheat grains. The endosperm transition zone was not sufficiently exposed, so the flour stream adjacent to the endosperm transition zone was not easily separated in the subsequent milling process.

[0087] Although Comparative Example 2.2 underwent controlled peeling, the primary conditioning only used single-stage water addition and single-stage standing. The softening difference between the endosperm transition zone and the central endosperm was only 11.4%, which was significantly lower than the 18.8% in Example 2. This indicates that the two-stage primary conditioning can more significantly establish the stratification difference, which directly affects the subsequent diversion efficiency.

[0088] Comparative Example 3.2 did not use a 36-mesh sieve for powder separation, indicating that even if a softening difference between the endosperm transition zone and the central endosperm has been established, if the corresponding powder flow is not effectively separated at the powder separation node, it is still difficult to form a high proportion of the initiating response powder group.

[0089] Secondly, in terms of the continuous retention rate of the middle wheat core material, Example 2.1 reached 91.6%, which is significantly better than Comparative Examples 1.2, 2.2 and 3.2, and especially significantly better than Comparative Example 4.2's 73.6%.

[0090] This indicates that the controlled peeling in this embodiment is not simply about exchanging more peeling for more endosperm exposure, but rather about finding a feasible balance window between exposing the endosperm transition zone and preserving the continuous wheat core structure.

[0091] In Comparative Example 4.2, although the extraction rate of the priming response powder group remained at a high level after excessive peeling, the continuous retention rate of the middle wheat core material decreased significantly, indicating that excessive peeling would destroy the continuous wheat core structure necessary for the subsequent formation of the skeleton powder group.

[0092] In other words, controlled peeling is not a simple adjustment of the regular peeling amount, but a creative process boundary that simultaneously serves the formation of the initial leavening powder group and the subsequent retention of the wheat core.

[0093] In terms of functional effects, the time for the aeration response powder group to form a dough after adding water in Example 2.1 was 82 seconds, which was significantly shorter than that of the four comparative groups; the fermentation height growth rate in the initial stage of aeration reached 31.5%, which was also significantly higher than that of each comparative group.

[0094] Meanwhile, the ash content of the ignition response powder group in Example 2.1 was only 0.46%, and the damaged starch content was only 4.4%, both of which were superior to the comparative examples.

[0095] The above results indicate that the two-stage primary conditioning process, along with low-temperature bran milling, 36-mesh cleaning, and pre-processing milling, is not simply aimed at increasing yield or reducing damage. Rather, it prioritizes the extraction of flour from the adjacent endosperm transition zone without significantly increasing ash content or damaging starch, thus forming a truly responsive flour group with pre-processing aeration capabilities. Table 2 shows that the continuous process chain of "controlled dehulling, two-stage primary conditioning to low-temperature bran milling, 36-mesh cleaning, and pre-processing milling" preferentially exposes, softens, and diverts the endosperm transition zone in the same batch of hard winter wheat, ultimately forming a responsive flour group while retaining continuous midwheat core material.

[0096] Compared to existing whole-process milling, single-stage conditioning, or non-separate cleaning processes, this process route can more stably establish a dual foundation of the front-end leavening powder group and the subsequent skeleton material receiving group. It has significant technological advantages and substantial differences in effect for obtaining high-gluten flour that has both rapid leavening and strong gas-holding capacity.

[0097] Example 3 Please refer to Figure 1 , Figure 2 and Figure 3 Specifically: In S3, the secondary conditioning and secondary settling rehydration are carried out on intermediate wheat core materials; After adding water, the moisture content of the middle wheat core material is adjusted to 14.0% to 15.5%; then it is left to stand for 4 to 10 hours to allow the moisture to migrate from the outer periphery of the middle wheat core material to the central endosperm. After two-stage conditioning and two-stage settling and rehydration, the central endosperm is in a milling state, resulting in secondary-conditioned wheat core material.

[0098] In S3, the secondary conditioned wheat core material is successively subjected to low-temperature limited-amplitude milling and fine screening; The temperature of the grinding rollers in the low-temperature limiting center mill is controlled below 30℃; During fine sieving, ash content and particle size range are used as sieving boundaries. Coarse powder streams with ash content higher than 0.45% are sieved out, while central endosperm powder streams with particle size within the preset range and ash content not higher than 0.45% are retained. The retained central endosperm powder streams are then aggregated to form an air-holding skeleton powder group. The ash and damaged starch content of the gas-holding skeleton powder group were lower than those of the leavening response powder group, and the GMP retention level of glutenin macropolymers in the gas-holding skeleton powder group was higher than that in the leavening response powder group.

[0099] In this embodiment, the application scenario remains consistent with that of Example 1, still targeting the preparation scenario of high-gluten flour for baking products with high water absorption, long fermentation and high specific volume. It is mainly used to illustrate the influence of secondary conditioning and secondary resting and moisturizing, as well as low temperature limited-amplitude milling and fine sieving on the formation quality of gas-holding skeleton flour.

[0100] This embodiment uses the same batch of hard winter wheat as in Example 1 as the starting material. Testing revealed that the raw material contained 15.1% protein, 36.8% wet gluten, 36.4% glutenin macropolymer GMP content, and the corresponding dough stability time was 12.6 min.

[0101] The raw materials are first processed according to the front-end processes in Examples 1 and 2, including impurity removal, wheat moistening, controlled peeling, two-stage first-stage conditioning, low-temperature hull milling, flour cleaning, and front-end core milling. The resulting powder group is separated first, and then the continuous wheat core structure is retained as the intermediate wheat core material.

[0102] It should be noted that, in this embodiment, secondary conditioning refers to the quantitative replenishment of water to the middle wheat core material to establish a new moisture gradient that migrates from the periphery to the center of the endosperm.

[0103] Secondary static rehydration means maintaining static state after water replenishment, allowing the water adsorbed on the outer layer to continue to diffuse into the central endosperm; Low-temperature limited-amplitude core milling means core milling under controlled conditions of roller temperature and fracture amplitude, so that the central endosperm is released in a controlled fracture manner rather than undergoing pulverization. Fine sieving means simultaneously screening the central endosperm powder stream by ash content boundaries and particle size range boundaries, thereby forming an air-holding framework powder group with low ash content, low damage starch and high GMP retention level of glutenin macropolymers.

[0104] In this embodiment, the initial moisture content of the middle wheat core material was measured to be 12.9% by a rapid moisture analyzer.

[0105] 50 kg of intermediate wheat kernel material was used as the initial feed for the experiment, and the target moisture content for secondary conditioning was set at 14.8%.

[0106] The amount of water required for secondary conditioning is calculated as follows: "Water added = Mass of intermediate wheat core material × (Target moisture content - Initial moisture content) ÷ (1 - Target moisture content)", which shows that 1.11 kg of water needs to be added.

[0107] During the water replenishment process, water is added in four stages using atomized spraying. After each spray, the mixture is turned over and mixed for 3 minutes in a closed spiral mixing device. After all the spraying is completed, the mixture is mixed for another 8 minutes to ensure that the water is evenly attached to the surface of the wheat core material.

[0108] The water-replenished mid-wheat core material is then spread out on a stainless steel turntable and left to stand at 22°C for 6 hours. During the standing process, the material is turned over every 2 hours to allow the moisture absorbed on the outer layer to continue migrating to the central endosperm.

[0109] After the settling period, the middle wheat core material was cut longitudinally and a compression test was performed. It was observed that the hardness and brittleness of the central endosperm decreased significantly, and the hardness gradient between the periphery and the center narrowed. This indicates that the central endosperm has formed a milling state with post-water absorption and low brittleness, thus obtaining secondary conditioned wheat core material.

[0110] Subsequently, the secondary conditioned wheat core material underwent low-temperature, limited-amplitude core milling. A two-roll core mill was used, with the roller temperature controlled at 27°C, the feed rate at 1.8 kg / min, the roller speed ratio at 1:1.18, and the core mill gap at 0.38 mm. The purpose of these parameters is to ensure the controlled rupture of the central endosperm in the secondary conditioned wheat core material, minimizing starch damage caused by high temperature and excessive shear.

[0111] The mixed powder stream obtained after milling enters the fine sieving process. The fine sieving process first tests the ash content of each powder stream and removes coarse powder streams with an ash content higher than 0.45%. Then, the powder streams with qualified ash content are screened for particle size, and the central endosperm powder streams with a particle size in the range of 110μm to 160μm are retained. The retained central endosperm powder streams are then gathered to form an air-holding skeleton powder group.

[0112] After the gas-holding skeleton powder group was formed, the ash content, damaged starch content, relative GMP retention rate of glutenin macropolymer, dough stability time and volume retention rate in the later stage of fermentation were measured.

[0113] Ash content was determined by the ignition method, damaged starch content was determined by the enzymatic method, and the relative retention rate of glutenin macropolymer GMP was calculated as the ratio of glutenin macropolymer GMP content in the gas-holding skeleton flour group to the glutenin macropolymer GMP content in the original target wheat. Dough stability time was determined by a farinograph. The volume retention rate in the later stage of fermentation was determined by a fermentation rheometer and calculated as the ratio of the maximum fermentation height Hm to the height H180 at 180 min of fermentation.

[0114] To illustrate the function of each process feature in this embodiment, four comparative examples are also provided: Comparative Example 1.3 does not perform secondary conditioning and secondary settling and rehydration; the intermediate wheat core material is directly fed into a regular mill and a regular sieve. The sample 2.3 underwent secondary conditioning, but the moisture content was only adjusted to 13.6% after secondary conditioning, and the settling and rehydration time was shortened to 2 hours. Comparative Example 3.3 underwent two-stage conditioning and two-stage static rehydration, but the core mill temperature was increased to 35℃, and the fracture amplitude was no longer controlled; Comparative Example 4.3 underwent two-stage conditioning, two-stage static rewetting, and low-temperature limited-amplitude core grinding. However, during fine sieving, the particle size range was no longer limited and only the ash content boundary was sieved.

[0115] Through the above experimental design, the effects of secondary conditioning, rewetting time, low-temperature limited-amplitude milling, and combined sieving according to ash content and particle size range on the formation of gas-holding skeleton powder can be observed respectively.

[0116] Table 3: Experimental results on the effects of secondary conditioning, low-temperature limited-amplitude milling, and fine sieving on the formation of gas-holding skeleton powder. Parameter name / unit Example 3.1 - Secondary conditioning + low-temperature limiting core milling + particle size range sieving Comparative Example 1.3 - Sample without secondary conditioning Comparative Example 2.3 - Low Moisture Content Short Rewetting Sample Comparative Example 3.3 - High-Temperature Conventional Core Grinding Sample Comparative Example 4.3 - Samples not sieved according to particle size range Moisture content after secondary conditioning / % 14.8 12.9 13.6 14.8 14.8 Secondary settling and rehydration time / h 6 0 2 6 6 Extraction rate of gas-holding skeleton powder group / % 39.6 31.4 34.2 36.1 41.8 Ash content of the gas-holding skeleton powder group / % 0.43 0.49 0.47 0.46 0.44 Gas-holding skeleton powder group damaged starch content / % 3.9 5.6 4.9 5.4 4.5 Relative GMP retention rate of glutenin macropolymers in gas-holding skeletal powder group / % 92.1 80.4 85.7 82.6 88.3 Dough stability time (min) corresponding to the gas-holding skeletal flour group 15.3 12.8 13.7 13.2 14.4 Volume retention rate in the later stage of fermentation / % 94.1 84.6 88.2 86.1 91 The moisture content after secondary conditioning in Table 3 represents the moisture content of the intermediate wheat core material after secondary water addition and mixing. It is used to reflect the control level of water replenishment of the intermediate wheat core material in the secondary conditioning stage. If the moisture content after secondary conditioning is too low, the subsequent softening of the central endosperm will be insufficient. If the moisture content after secondary conditioning is too high, it will easily lead to excessive wetness on the material surface and affect the subsequent controlled core milling. The secondary settling and rehydration time indicates the length of time the middle wheat core material is kept still after the secondary conditioning is completed. It is used to reflect the duration of the migration of the peripheral adsorbed water to the central endosperm. The more sufficient the secondary settling and rehydration time, the easier it is for the central endosperm to form a milling state with post-water absorption and low brittleness. It should be noted that the term "milling state" in this application is not a general term, but refers to the measurable processing state of wheat grains or wheat cores after conditioning.

[0117] The milling state in S2 specifically refers to the following: after the first-stage conditioning, the overall moisture content of the dehulled wheat grains reaches 16.2% to 17.0%, and the local moisture content of the endosperm transition zone is 0.8 to 1.5 percentage points higher than that of the central endosperm; under the same slice thickness and the same compression conditions, the compression hardness of the endosperm transition zone is 10% to 25% lower than that of the central endosperm, and the compression deformation of the endosperm transition zone is 15% to 35% higher than that of the central endosperm.

[0118] The powder state in S3 specifically refers to the following: after the secondary conditioning and secondary settling and rehydration, the overall moisture content of the middle wheat core material reaches 14.0% to 15.5%, and the local moisture content of the central endosperm increases by 1.0 to 2.0 percentage points compared with before the secondary conditioning; under the same slice thickness and the same compression conditions, the compression hardness of the central endosperm decreases by 15% to 30% compared with before the secondary conditioning, and the peak burst load of the central endosperm decreases by 10% to 25% compared with before the secondary conditioning.

[0119] The local moisture content was determined by the stratified sampling and drying method, while the compression hardness, compression deformation, and peak burst load were obtained by compressing the sliced ​​samples using a texture analyzer.

[0120] In other words, the powdering state does not simply mean that the material has softened, but rather that the material has reached a moisture and mechanical state in which it can stably release the target powder flow in the subsequent corresponding grinding process.

[0121] The extraction rate of gas-holding skeleton powder group represents the percentage of the mass of the final aggregated gas-holding skeleton powder group relative to the mass of the intermediate wheat core material entering S3. It is used to reflect the efficiency of the intermediate wheat core material in being transformed into the target functional powder group after secondary conditioning, low-temperature limiting milling and fine sieving. The ash content of the gas-holding skeleton powder group represents the percentage of inorganic matter remaining in the sample mass after the gas-holding skeleton powder group is ignited. It is used to reflect the degree of mixing of the outer high-ash group. The lower the value, the closer the gas-holding skeleton powder group is to the central endosperm source powder stream. The damaged starch content of the gas-holding skeleton powder group indicates the proportion of starch in the gas-holding skeleton powder group whose structure is damaged due to shearing and extrusion of the core mill. It is used to reflect the degree of mechanical damage to the central endosperm powder flow during the S3 core milling stage. The lower the value, the more fully the skeleton structure is preserved by the low-temperature limited core milling. The relative retention rate of glutenin macropolymer GMP in the gas-holding skeleton powder group represents the ratio of the GMP content of glutenin macropolymer detected in the gas-holding skeleton powder group to the GMP content of the original glutenin macropolymer of the target wheat, expressed as a percentage. It is used to reflect the degree of retention of the central endosperm protein skeleton during the S3 separation process. The higher the value, the more the gas-holding skeleton powder group is conducive to undertaking the support function of the subsequent skeleton. The dough stability time corresponding to the gas-holding skeletal powder group represents the dough stability time measured in a farinograph after the test dough is made from the gas-holding skeletal powder group alone. It is used to reflect the skeletal stability ability of the gas-holding skeletal powder group in the kneading and fermentation stages. The larger the value, the stronger the gluten skeletal bearing capacity of the gas-holding skeletal powder group.

[0122] As can be seen from Table 3, Example 3.1 is superior to the other examples in several core indicators of this example, and its advantages have a clear process source.

[0123] First, considering the two indicators of ash content and damaged starch content of the gas-holding skeleton powder, Example 3.1 has 0.43% and 3.9% respectively, which are significantly better than Comparative Example 1.3 (0.49% and 5.6%), Comparative Example 2.3 (0.47% and 4.9%), and Comparative Example 3.3 (0.46% and 5.4%), and also better than Comparative Example 4.3 which only considers ash content sieving.

[0124] This result shows that after the central endosperm enters a post-water-absorbing and low-brittleness state through two-stage conditioning and two-stage static rewetting, the use of low-temperature limited-amplitude core milling can significantly reduce the mechanical damage to the central endosperm during the cracking process. Furthermore, the simultaneous use of ash boundary and particle size range boundary in the fine sieving stage is beneficial for screening out the powder stream that truly represents the stable structure of the central endosperm, rather than retaining a large number of structurally uneven powder streams.

[0125] Comparative Example 1.3 did not have secondary conditioning and secondary static rehydration. The middle wheat core material directly entered the ordinary endosperm mill. Therefore, the central endosperm was still in a brittle and hard state, and was more likely to produce pulverization and high damage starch after milling. Although Comparative Example 3.3 had secondary conditioning and rehydration, the end milling temperature was increased to 35℃, which aggravated the local temperature rise and shear damage during the end milling process, so the damaged starch content was still relatively high.

[0126] Secondly, considering the three indicators of relative GMP retention rate of glutenin macropolymer in the gas-holding framework powder group, dough stability time and volume retention rate in the later stage of fermentation, Example 3.1 achieved 92.1%, 15.3 min and 94.1% respectively, which were significantly better than the other pairs.

[0127] This result indicates that the secondary conditioning and secondary settling in this embodiment are not simply for adding water, but to allow the central endosperm to enter the milling process under a gentler and more controlled condition, thereby preserving the protein backbone of the central endosperm to a greater extent in subsequent milling.

[0128] Low-temperature limited-amplitude milling and fine sieving further translate this protein skeleton advantage into longer dough stability time and higher volume retention in the later stages of fermentation.

[0129] In particular, in Comparative Example 4.3, the extraction rate of the gas-holding skeleton powder group reached 41.8%, which is higher than that of Example 3.1 on the surface. However, the dough stability time and volume retention rate in the later stage of fermentation corresponding to the gas-holding skeleton powder group are still lower than those of Example 3.1.

[0130] This indicates that extracting more gas-holding skeleton powder is not necessarily better. Instead, it is necessary to screen out the central endosperm powder stream that is truly suitable for undertaking the function of the subsequent skeleton by using the particle size range boundary. If only ash content is used for sieving without further constraint according to the particle size range, although the extraction rate may be improved, the consistency and structural stability of the powder stream will decrease, which will ultimately weaken the gas-holding effect in the later stage.

[0131] From the perspective of process chain integrity, this embodiment, together with Embodiment 1 and Embodiment 2, constitutes a continuous main chain.

[0132] Example 2 has already demonstrated that controlled peeling, two-stage primary conditioning, low-temperature hull milling, flour cleaning, and front-end milling can stably form a reactive flour group while retaining the core material. This example further illustrates that the core material is not ordinary residual flour, but can be further transformed into a gas-holding skeletal flour group through secondary conditioning, secondary resting and rehydration, low-temperature limited-amplitude milling, and fine sieving. Therefore, this example is not a simple optimization of the ordinary milling route, but rather, after the reactive flour group has been formed, a second flour group formation path is established around the core material, allowing the gas-holding function to be released directionally from the same batch of target wheat in the form of a separate flour group.

[0133] This approach, which involves the separate formation of a starter and a gas-holding powder components to ultimately produce high-gluten flour for baking with high fermentation and gas retention, offers a more targeted solution to the problem of balancing starter formation and gas retention in high-water-absorption, long-fermentation scenarios compared to existing methods of integrated flour production, uniform flour blending, or reliance solely on back-end improvers.

[0134] Example 4 Please refer to Figure 1 Specifically: In S4, the powder ratio is determined in two steps; First, use the air-holding skeleton powder group as the base powder group, and gradually add the ignition response powder group to determine the minimum amount to meet the front-end ignition index; And based on the minimum addition amount, adjust the addition amount of the gas-holding skeleton powder group to determine the minimum addition amount that meets the gas-holding index of the later stage; The amount of the initiating response powder group is 20% to 45% of the total mass of the finished powder, and the amount of the gas-holding skeleton powder group is 55% to 80% of the total mass of the finished powder.

[0135] In S4, the starter-response powder group and the gas-holding skeleton powder group are mixed according to the powder ratio, and then homogenized and allowed to stand for homogenization to obtain high-gluten flour for baking with high fermentation and gas-holding capacity. The homogenization time should be controlled between 10 min and 40 min. After homogenization and static homogenization, the initiating response powder group and the gas-holding skeleton powder group are uniformly dispersed without changing their respective source structures.

[0136] In this embodiment, the same batch of hard winter wheat as in Example 1 was used as raw material. This batch of raw material underwent impurity removal, wheat moistening, controlled-volume dehulling, two-stage primary conditioning, low-temperature hull milling, flour cleaning, and pre-processing milling according to the processes described in Examples 1, 2, and 3. This first separated the responsive flour group, while simultaneously retaining the core material. Then, the core material underwent secondary conditioning, secondary resting and moistening, low-temperature limited-amplitude milling, and fine sieving to separate the gas-holding framework flour group. This embodiment focuses on disclosing the method for determining the flour blending ratio, as well as the homogenization and resting homogenization methods after blending.

[0137] It should be noted that the "minimum addition amount" in this embodiment refers to the minimum addition ratio that enables the mixed powder sample to simultaneously meet the front-end initiation index for the first time after the initiation response powder group is added to the gas-holding skeleton powder group. The minimum addition amount indicates the minimum addition ratio that allows the mixed powder sample to simultaneously meet the gas-holding index for the first time, provided that the initial aeration index of the front stage has been established. Homogenization means that the two powder components are uniformly dispersed macroscopically by mechanical mixing without re-grinding or re-sieving. The static homogenization process means that after the homogenization and mixing of powders are completed, the powders are kept static under closed and low-disturbance conditions, so that the initiating response powder group and the gas-holding skeleton powder group can achieve a more stable particle distribution and local moisture rebalancing without changing their respective source structures.

[0138] In this embodiment, the first step is to screen the powder. The gas-holding skeleton powder group is used as the base powder group. Six groups of samples are set with the addition ratio of the initiation response powder group being 20%, 25%, 30%, 35%, 40% and 45%, respectively. Correspondingly, the proportion of the gas-holding skeleton powder group is set to 80%, 75%, 70%, 65%, 60% and 55%.

[0139] All six groups of samples were premixed under the same mixing conditions, and the time for water addition to form a dough and the growth rate of the fermentation height in the initial fermentation stage were measured. The time for water addition to form a dough was measured using a farinograph, and the time required from the start of water addition until the farinograph curve first reached 500 FU was recorded as the water addition to form a dough. The growth rate of the fermentation height in the initial fermentation stage was measured using a fermentation rheometer, with the initial height at the end of sample loading recorded as H0 and the dough height at 30 min of fermentation recorded as H30, calculated as [(H30-H0) / H0]×100%.

[0140] The criteria for meeting the initial fermentation indicators are that the time for water to form a dough is no more than 85 seconds and the initial fermentation height growth rate is no less than 30%.

[0141] Test results show that when the amount of the initiation response powder group reaches 35%, the sample meets the two front-end initiation indicators mentioned above for the first time. Therefore, 35% is determined as the minimum amount of the initiation response powder group.

[0142] Based on the results of the first step screening, the second step of flour selection was carried out. With the amount of the starter-response flour group fixed at 35%, three groups of samples were set up with gas-holding framework flour groups of 65%, 60%, and 55%. The dough stability time and volume retention rate in the later stages of fermentation were measured for each group. The dough stability time was measured using a farinograph, determined by the time interval between the first intersection of the upper edge of the farinograph curve with the 500FU line and the point where it leaves the 500FU line. The volume retention rate in the later stages of fermentation was measured using a fermentation rheometer, with the maximum fermentation height recorded as Hm and the dough height at 180 min of fermentation recorded as H180, calculated as (H180 / Hm) × 100%.

[0143] The conditions for meeting the gas retention index in the later stage are that the dough stability time is not less than 14.5 min and the volume retention rate in the later stage of fermentation is not less than 93%.

[0144] Test results show that when the proportion of gas-holding skeleton powder is 65%, the sample meets the two downstream gas-holding indicators mentioned above for the first time. Therefore, 65% is determined as the minimum addition amount of gas-holding skeleton powder.

[0145] Therefore, the powder ratio of the initiation response powder group to the gas-holding skeleton powder group was determined to be 35:65.

[0146] After the powder mixing ratio is determined, weigh 35 kg of the initiating response powder group and 65 kg of the air-holding skeleton powder group, and put them into the horizontal ribbon mixer for homogenization and mixing.

[0147] The mixing machine speed was controlled at 18 rpm, and the mixing time was controlled at 8 minutes. After mixing, the mixed powder sample was immediately transferred to a closed stainless steel turnover box and allowed to stand at 22℃ for 15 minutes for homogenization.

[0148] During the settling process, no further turning, sieving, crushing, or other treatments that would alter the source structure of the powder group are performed. The powder is kept in a low-disturbance, closed state, allowing the initiation response powder group and the gas-holding skeleton powder group to achieve uniform dispersion without changing their respective source structures.

[0149] After the homogenization process is completed, the resulting high-gluten flour with high fermentation and gas retention properties for baking is tested.

[0150] The test results showed that the time for the finished powder to form a dough after adding water was 82s, the initial fermentation height increase rate was 31.5%, the dough stability time was 14.8min, the volume retention rate in the later fermentation stage was 93.6%, and the bread specific volume reached 5.62mL / g.

[0151] This demonstrates that determining the powder ratio in two steps, based on the initial leavening index and the subsequent gas-holding index, and then using appropriate static settling after homogenization, not only enables the two powder groups to achieve stable dispersion, but also allows the initial leavening ability and the subsequent gas-holding ability to be simultaneously reflected in the same finished powder.

[0152] To illustrate the role of each process feature in this embodiment, this embodiment can be compared with empirical equal-volume powder mixing, single-step powder mixing, powder mixing without settling and homogenization, and processing routes with excessively long settling time.

[0153] While empirical equal-quantity flour mixing can improve the rising speed, it can easily weaken the gas retention in the later stages; single-step flour mixing simplifies the operation, but it is difficult to simultaneously take into account both the rising at the beginning and the gas retention in the later stages; failure to allow the flour to stand and homogenize after mixing will lead to uneven local distribution of the two types of flour in the finished product, affecting the clumping and fermentation performance; excessively long standing time may cause uneven local moisture absorption of the flour, weakening the functional division advantage of the dual-flour source structure.

[0154] In contrast, this embodiment uses a two-step powder mixing method of "first determining the minimum amount to add, then determining the minimum amount to add" to simultaneously incorporate the initial aeration requirements and the subsequent gas holding requirements into the powder mixing process. Then, through homogenization and mixing of powders and static homogenization within a range of 10 min to 40 min, with a preferred static time of 15 min, the aeration response powder group and the gas holding skeleton powder group are uniformly dispersed without structural damage.

[0155] The resulting finished flour is more stably applicable to baking products requiring high water absorption, long fermentation, and high specific volume, thus fully demonstrating the effectiveness of the process in this embodiment.

[0156] To verify the rationality of limiting the target wheat to a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 min, five groups of hard winter wheat from different sources, all suitable for baking and milling, were selected as raw material samples. The glutenin macropolymer GMP content and dough stability time of each group of raw material samples were measured. Under the condition that other process conditions remained the same, the controlled amount of dehulling, primary conditioning, low-temperature bran milling, flour cleaning, and front-end milling were carried out in sequence according to the process described in Example 1 to form the starter-response flour group and the intermediate wheat core material. Then, the intermediate wheat core material was subjected to secondary conditioning, secondary static rehydration, low-temperature limited-amplitude milling, and fine sieving according to the process described in Example 3 to form the gas-holding skeleton flour group. Finally, the flour blending ratio was determined according to the method described in Example 4 to obtain the finished flour.

[0157] The compatibility of different raw material samples was compared using the time for water addition to form dough, dough stability time, volume retention rate in the later stage of fermentation, and bread specific volume of finished flour as verification indicators. The results are shown in Table 4. Table 4: Results of the Validation Experiment for Screening Conditions of Target Wheat test subjects GMP content of glutenin macropolymers / % Dough stability time (min) Does it meet the target wheat conditions? Finished product water addition time to form dough / seconds Finished dough stability time / min Volume retention rate in the later stage of fermentation / % Bread volume (mL / g) Sample A 36.4 12.6 yes 82 14.8 93.6 5.62 Sample B 35.2 12.1 yes 84 14.5 92.8 5.55 Sample C 34.7 12.4 no 85 13.7 88.9 5.31 Sample D 35.6 11.5 no 90 13.4 87.6 5.24 Sample E 33.9 11.1 no 94 12.8 84.1 5.02 As can be seen from Table 4, both Sample A and Sample B meet the conditions that the GMP content of glutenin macropolymer is not less than 35% and the dough stability time is not less than 12 min. The finished flour prepared according to the process of this invention shows good performance in terms of water addition time, dough stability time, volume retention rate in the later stage of fermentation, and bread specific volume.

[0158] Among them, the finished flour prepared by sample A had a dough-forming time of 82s after adding water, a dough stability time of 14.8min, a volume retention rate of 93.6% after fermentation, and a bread specific volume of 5.62mL / g; although sample B was slightly lower than sample A, it still maintained a high level overall.

[0159] In contrast, although the dough stability time of sample C reached 12.4 min, the GMP content of glutenin macropolymer was only 34.7%, which did not reach the limit of 35%. The dough stability time and volume retention rate of the finished flour were significantly reduced. This indicates that when the protein polymer skeleton of the raw material is insufficient, even if the overall rheological basis is acceptable, it is difficult to fully form a gas-holding skeleton powder group with strong gas-holding capacity in the later stage.

[0160] Although sample D had a glutenin macropolymer GMP content of 35.6%, the dough stability time was only 11.5 min, which did not meet the limit of 12 min. The dough formation time of the finished flour was extended to 90 s, and the volume retention rate in the later stage of fermentation decreased to 87.6%. This indicates that when the overall rheological stability of the raw materials is insufficient, although they have certain skeletal potential, it is difficult to form a stable balance between the initial fermentation and the gas retention in the later stage.

[0161] The GMP content of glutenin macropolymers and the stability time of the raw dough in sample E did not reach the limit values, and the corresponding performance indicators of the finished flour were at the lowest level.

[0162] Therefore, setting the target wheat to have a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 minutes can provide a stable raw material basis for the stepwise formation of the starter-response powder group and the gas-holding skeleton powder group, and can also ensure that the finished flour after subsequent blending has both good initial starter-response ability and subsequent gas-holding ability.

[0163] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a high-gluten flour for baking with high fermentation and gas-holding capacity, characterized in that, Includes the following steps: S1. Select target wheat with a glutenin macropolymer GMP content of not less than 35% and a dough stability time of not less than 12 min, and remove impurities, moisten, and let stand to obtain pretreated wheat grains. S2. Controlled dehulling of pretreated wheat grains removes the outer bran layer and aleurone layer, while retaining the endosperm transition zone adjacent to the aleurone layer, resulting in dehulled wheat grains. The dehulled wheat grains undergo primary conditioning to create a milling state where the endosperm transition zone absorbs water and softens first, resulting in primary conditioned wheat grains. The primary conditioned wheat grains are then subjected to low-temperature bran milling, cleaning, and front-end core milling to separate the responsive powder group and the intermediate wheat core material. The responsive powder group is mainly composed of powder from the endosperm transition zone. S3. The intermediate wheat core material is subjected to secondary conditioning and secondary static rehydration to make the central endosperm in the intermediate wheat core material form a powder-making state, and the secondary conditioning wheat core material is obtained. The secondary conditioning wheat core material is subjected to low-temperature limited-amplitude core milling and fine sieving to separate the gas-holding skeleton powder group, which is mainly composed of powder from the central endosperm. S4. Measure the water addition and dough formation speed and the initial fermentation height growth rate of the leavening response powder group to obtain the first-stage leavening index; measure the dough stability time and volume retention rate of the gas-holding framework powder group to obtain the second-stage gas-holding index; determine the powder ratio based on the first-stage leavening index and the second-stage gas-holding index; mix the leavening response powder group and the gas-holding framework powder group according to the powder ratio to obtain high-gluten flour for baking with high fermentation gas-holding capacity.

2. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 1, characterized in that, In S2, the controlled peeling is carried out layer by layer along the outer periphery of the pretreated wheat grain until the endosperm transition zone is continuously exposed on the surface of the pretreated wheat grain, and the peeling is stopped without damaging the continuous internal core structure, thus obtaining peeled wheat grains. The amount of hulling is controlled to be between 3.5% and 8.5% of the pretreated wheat grain mass.

3. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 1, characterized in that, In S2, the primary conditioning includes a first stage of water addition and a second stage of water addition; After adding water in the first stage, the moisture content of the peeled wheat grains is adjusted to 15.5%–16.2%, and then left to stand for 1–3 hours. After adding water in the second stage, the moisture content of the hulled wheat grains is adjusted to 16.2%–17.0%, and then left to stand for 1–3 hours. After primary conditioning, the softening degree of the endosperm transition zone is higher than that of the central endosperm.

4. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 1, characterized in that, In S2, the primary conditioned wheat grains undergo low-temperature bran milling, flour cleaning, and pre-milling in sequence; The temperature of the grinding rollers in the low-temperature leather mill is controlled below 30°C, and the grinding gap of the preceding leather mill is controlled between 1.2 mm and 1.5 mm. The powder is separated from the powder flow in the transition zone adjacent to the endosperm using a 36-mesh sieve; The rotational speed of the front core mill is controlled between 550 rpm and 650 rpm; The separated adjacent endosperm transition zone powder flows are merged to form an initiation response powder group, while the remaining continuous wheat core portion constitutes the intermediate wheat core material.

5. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 1, characterized in that, In S3, the secondary conditioning and the secondary settling and rehydration are carried out on intermediate wheat core material; After adding water, the moisture content of the middle wheat core material is adjusted to 14.0% to 15.5%; then it is left to stand for 4 to 10 hours to allow the moisture to migrate from the outer periphery of the middle wheat core material to the central endosperm. After two-stage conditioning and two-stage settling and rehydration, the central endosperm is in a milling state, resulting in secondary-conditioned wheat core material.

6. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 5, characterized in that, In S3, the secondary conditioned wheat core material is successively subjected to low-temperature limited-amplitude milling and fine screening; The temperature of the grinding rollers in the low-temperature limiting mill is controlled below 30°C; During the fine sieving process, ash content and particle size range are used as the sieving boundaries. Coarse powder streams with ash content higher than 0.45% are sieved out, while central endosperm powder streams with particle size within the preset range and ash content not higher than 0.45% are retained. The retained central endosperm powder streams are then aggregated to form an air-holding skeleton powder group. The ash content and damaged starch content of the gas-holding skeleton powder group were lower than those of the foaming response powder group, and the GMP retention level of glutenin macropolymers in the gas-holding skeleton powder group was higher than that in the foaming response powder group.

7. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 1, characterized in that, In S4, the powder ratio is determined in two steps; The amount of the initiating response powder group accounts for 20% to 45% of the total mass of the finished powder, and the amount of the gas-holding skeleton powder group accounts for 55% to 80% of the total mass of the finished powder.

8. The method for preparing a high-gluten flour for baking with high fermentation and gas retention properties according to claim 6, characterized in that, In S4, the starter-response powder group and the gas-holding skeleton powder group are mixed according to the powder ratio, and then homogenized and allowed to stand for homogenization to obtain high-gluten flour for baking with high fermentation and gas-holding capacity. The settling and homogenization time is controlled between 10 min and 40 min.

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