Nutritional flour rich in wheat germ and high dietary fiber and preparation method thereof

Abstract

The invention relates to the field of flour production, particularly discloses nutritional flour rich in wheat germ and high dietary fibers and a preparation method of the nutritional flour, and aims to solve the problems that the wheat germ dietary fibers are sheared and damaged and are lost along with bran, the nutrient content is difficult to reach the standard, the distribution is non-uniform, and the shelf and dough texture are unstable in the conventional flour milling process. The wheat germ dietary fiber noodles comprise the following components in parts by mass: 80-94 parts of wheat flour, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber and 12-14.5 parts of water. The preparation method comprises the following steps: cleaning and grading unprocessed grains, preparing a kombucha dietary fiber dispersion liquid, wetting and blending wheat, carrying out temperature-controlled roller grinding and crushing, sifting and purifying, adding germ fine powder and correcting the proportion, synergistically adding calcium salt, metering, blending and homogenizing, and calibrating and stabilizing moisture. The kombucha dietary fibers are added through wheat wetting, temperature-controlled roller milling and germ dietary fiber re-adding are carried out, so that germ dietary fiber retention is improved, dough stability is promoted, and the breakage rate of noodle products is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flour production, and particularly relates to a kind of high dietary fiber nutrition flour rich in wheat germ and a preparation method thereof. BACKGROUND

[0002] Industrialized preparation of flour usually includes cleaning, conditioning, breaking and grinding, screening, purification and powder blending, in order to improve the whiteness and shelf life of flour, the process of screening after multi-roller milling in breaking and grinding will actively remove bran and maximize the removal of fat and perishable wheat germ, resulting in a large loss and structural damage of wheat germ dietary fiber in flour. High-speed roller milling will first shear the wheat germ dietary fiber network into fine particles, and then concentrate the bran in the screening and purification section, directly exacerbating the loss and breakage of wheat germ dietary fiber. In the master's thesis "Effect of Red Tea Fermentation Dietary Fiber on Wheat Starch and Noodle Quality" published by Baijin of Henan University of Technology in China, the molecular interaction mechanism of red tea fermentation dietary fiber and wheat starch and the correlation between the interaction and the quality of flour products are explored. The red tea fermentation dietary fiber is added to the wheat flour in the same proportion to make noodles, and the results show that when the addition amount is 5%, the noodles have the highest comprehensive score in sensory indicators such as color, hardness, smoothness and taste. It can be seen that the red tea fermentation dietary fiber has high hydrophilicity and water retention capacity, large specific surface area, strong nanofiber network film forming and adhesion bridging capacity, can form physical interaction with starch or protein and improve the dough structure, and related studies show that it is beneficial to water retention and texture optimization of dough in flour products. Therefore, a kind of high dietary fiber nutrition flour rich in wheat germ and a preparation method thereof are proposed, in which red tea fermentation dietary fiber is added in the conditioning stage and fully pre-wetted, so that it can form a micro-network buffer bonding layer on the interface of endosperm-germ-bran before roller milling, reducing the subsequent roller milling shear damage; and in the subsequent screening-purification stage, the adhesion and particle size control effect are utilized to improve the retention and re-addition efficiency of the sheared germ fiber with the flour, thereby making up for the decrease of wheat germ dietary fiber content in flour caused by roller milling and screening, and improving the nutritional value of flour. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a kind of high dietary fiber nutrition flour rich in wheat germ and a preparation method thereof, by adding red tea fermentation dietary fiber in conditioning, temperature-controlled roller milling and germ dietary fiber re-addition, to improve the retention of germ dietary fiber, promote dough stability and reduce the noodle product breakage rate.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0005] A nutritious flour rich in wheat germ and dietary fiber comprises, by weight, 80-94 parts of wheat flour conforming to GB / T1355-2021, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber, and 12-14.5 parts of moisture. The wheat germ dietary fiber includes neutral detergent fiber and acid detergent fiber from wheat germ, and is measured using a combination of methods from GB / T5009.10 and GB / T5009.88. The kombucha dietary fiber is obtained by washing, neutralizing, dehydrating, and drying bacterial cellulose from a black tea fermentation system. It has an average fiber diameter of 0.02-0.15 μm, a length of 1-50 μm, and a water absorption value ≥8 g / g, and coexists with wheat dietary fiber at a weight ratio of 2:1 to 8:1.

[0006] As a further embodiment of the flour of the present invention, the wheat dietary fiber is composed of two types of flour blended in a mass ratio of 40:60 to 60:40: the first type of flour is wheat germ flour obtained by cold-pressing defatting and supercritical carbon dioxide defatting combined treatment; the second type of flour is wheat cell wall dietary fiber obtained by roller milling, which is extracted by enzymatic desaturation and alkali-soluble acid precipitation, and then precipitated with 60% to 80% volume fraction ethanol, desalted, and dried at 40°C to 55°C; the total mass of wheat germ dietary fiber after blending the two types of flour accounts for ≥60% of the total mass of the blended flour.

[0007] As a further embodiment of the flour of the present invention, the process for determining the content of wheat germ dietary fiber using a combination of GB / T5009.10 and GB / T5009.88 methods includes:

[0008] Step 11: Pre-treat the sample according to GB5009.88, and enzymatically hydrolyze it with heat-resistant α-amylase, protease and glucoamylase at the specified pH and temperature to remove digestible starch and protein, and remove oligomeric soluble components by ethanol precipitation to obtain enzyme-treated residue.

[0009] Step 12: Extract the residue obtained in step 11 using the neutral detergent method described in GB5009.88. After filtration, drying at 105°C, scalding, and blank deduction of protein and ash content, calculate the dry basis of the neutral detergent fiber in g / g.

[0010] Step 13: The filter residue obtained in Step 12 is further subjected to acid washing. Referring to the acid treatment intensity and operation points specified in GB / T 5009.10, the specified acid detergent is used to treat the residue under constant temperature reflux conditions to dissolve and remove acid-soluble components such as hemicellulose. Then, the residue is filtered, dried at 105℃ and ashed, and protein and ash content are deducted and reagent blank is corrected. The dry basis of the acid-washed fiber is calculated in g / g.

[0011] Step 14: The total amount of neutral detergent fiber and acid detergent fiber in wheat germ is taken as the dietary fiber content of wheat germ, and is expressed as the average of two parallel measurements.

[0012] Step 15: If the fat content of the dry sample is >5%, it should be degreased according to the standard before measurement.

[0013] As a further embodiment of the flour of the present invention, the process for obtaining kombucha dietary fiber includes:

[0014] Step 21, Preparation of raw materials and black tea base: Take drinking-grade water, add black tea at 0.5% to 1.0% m / V, boil and steep for 5 to 10 minutes, filter to obtain tea liquor, add sucrose at 6% to 10% m / V while hot and dissolve, cool to 25 to 30°C, add yeast extract powder at 0.1% to 0.3% m / V as needed, pour the tea liquor into a fermentation pan, with a liquid depth of 2 to 6 cm, and sterilize at 121°C for 15 minutes;

[0015] Step 22, Inoculation and Static Fermentation: Under aseptic conditions, inoculate with kombucha symbiotic liquid, which contains bacterial film and fermentation liquid. The inoculation amount is 10% to 30% V / V, the pH is adjusted to 5.0 to 5.6, and the mixture is allowed to stand at 25 to 30°C for 7 to 14 days to form a dense bacterial cellulose film on the liquid surface. During this period, the pH and film thickness are recorded daily.

[0016] Step 23, membrane removal and pre-washing: Remove the bacterial membrane, remove the attached fermentation liquid, and gently rinse with running drinking water until the surface is no longer sticky and the odor is significantly reduced. If necessary, quickly soak in 1% V / V food-grade acetic acid aqueous solution for 5-10 minutes to decolorize and remove odor, and then rinse with water.

[0017] Step 24, alkaline washing to remove impurities: Place the pre-washed membrane strips in 0.1% to 1.0% m / V NaOH solution and treat at 60 to 90°C for 30 to 120 minutes, stirring gently during the process. After pouring out the alkaline solution, wash repeatedly with warm water until the washing solution is close to neutral pH, colorless and foam-free.

[0018] Step 25, Neutralization and fine washing: Adjust the pH of the cellulose after alkali washing to 6.0 to 6.8 with 0.05% to 0.5% m / V food-grade organic acid, let it stand for 10 to 30 minutes, then rinse with drinking water until the pH is 6.0 to 7.0 and the conductivity is close to the background value of the incoming water, and then wash it thoroughly.

[0019] Step 26, Mechanical dehydration and drying into fibers: The purified wet film is sheared and pulped at 3000-8000 rpm for 1-3 minutes to obtain a uniform slurry. The slurry is then centrifuged at 3000-6000 g for 5-10 minutes until the moisture content reaches 60%-75%. The slurry is pre-frozen at -40℃ for 2-4 hours and then freeze-dried under vacuum for 12-24 hours. The dried product is then pulverized by air jet milling at a low temperature (temperature controlled below 45℃) and sieved to obtain kombucha dietary fiber of the target particle size.

[0020] As a further embodiment of the flour of the present invention, in step 26, the target particle size of kombucha dietary fiber includes 1-30 μm for the dispersion and 50-150 μm for the powder, wherein the kombucha dietary fiber has a moisture content of ≤7.0% by mass, an ash content of ≤1.0% by mass, a pH of 6.0-7.0, and a microbial content that meets the food control requirements.

[0021] As a further embodiment of the flour of the present invention, the flour further includes 0.05 to 0.30 parts by weight of food-grade organic acid salt buffer, wherein the food-grade organic acid salt buffer includes one or two of sodium citrate, potassium sodium tartrate or sodium malate.

[0022] As a further embodiment of the flour of the present invention, the flour further includes 0.05 to 0.20 parts by weight of food-grade soluble calcium salt, wherein the food-grade soluble calcium salt includes one of calcium citrate, calcium lactate or calcium hydrogen phosphate.

[0023] A method for producing a nutritious flour rich in wheat germ and dietary fiber, comprising the following steps:

[0024] Step S1, Raw grain cleaning and grading: Airflow gravity and magnetic separation are used together to remove impurities from the raw grain, and the impurity content is controlled to be ≤1%. Grading is carried out according to particle size and bulk density.

[0025] Step S2, preparation of kombucha dietary fiber dispersion: Take dry powder kombucha dietary fiber with a target particle size of 1-30 μm, add drinking water at a solid-liquid ratio of 1:20-1:40 m / V, and shear at high speed of 8000-15000 rpm for 3-10 min to obtain a uniform dispersion. Add food-grade organic acid salt buffer to the main powder stream in the direction of preparation, and adjust the pH to 6.0-6.8 to prepare kombucha dietary fiber dispersion;

[0026] Step S3, Wheat conditioning: Spray the raw wheat grains with the kombucha dietary fiber dispersion obtained in step S2 and water to adjust the moisture content of the wheat grains to 15.0% to 17.0%, and let them stand at room temperature for 12 to 24 hours;

[0027] Step S4, temperature-controlled roller mill crushing: multi-stage roller mill, controlling the roller temperature ≤35℃ and the linear speed difference 1.2~2.5rpm, and recording energy consumption and powder output rate in real time;

[0028] Step S5, sieving and purification: According to the powder path configuration, perform grading sieving and cleaning, collect the main powder flow, bran secondary flow, and bran core secondary flow, and monitor online to ensure that the 100-mesh sieve passing rate is ≥85% and the fatty acid value meets the preset requirements;

[0029] Step S6, adding back and adjusting the proportion of wheat germ fine powder: Select wheat germ fine powder from the bran core stream, dry it with hot air at 40-55℃ until the moisture content is ≤7.0%, pass it through a 100-mesh sieve and ≥90%, and then add it back to the main powder according to the target nutrient setting to achieve the total target of 3-12 parts by weight of wheat germ dietary fiber.

[0030] Step S7, synergistic addition of calcium salt: Add food-grade soluble calcium salt to the mixed powder in the direction of mixing. The average particle size of the food-grade soluble calcium salt is 3-8 μm, and the mass ratio of the calcium salt to kombucha fiber is 0.05:1-0.3:1.

[0031] Step S8, Metering and Homogenization: Add 80-94 parts of wheat flour conforming to GB / T1355-2021, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber, food-grade organic acid salt buffer, and food-grade soluble calcium salt to a high-speed horizontal mixer by mass, and homogenize at low temperature for 3-8 minutes, with the material outlet temperature rise ≤5℃;

[0032] Step S9, Moisture calibration and stabilization: Using atomized water replenishment or low-temperature ventilation, adjust the moisture content of the finished product to 12.0-14.5 parts by weight, let it stand for 4-12 hours to equalize, and check the flour indicators according to the preset test items while conducting standard flour testing. After verifying that it meets the standards, release it and package the finished product in nitrogen-filled light-proof composite bags.

[0033] As a further embodiment of the manufacturing method of the present invention, in step S6, the amount of germ powder added back accounts for 2 to 8 parts by weight of the finished product.

[0034] As a further embodiment of the manufacturing method of the present invention, in step S9, the preset detection items include the determination of the dietary fiber content of kombucha in the finished flour and the determination of the dietary fiber content of wheat germ.

[0035] The technical effects of this invention are as follows: By introducing kombucha dietary fiber dispersion during the wheat-rehydration stage, this invention utilizes the hydrophilic, film-forming, and adhesive bridging capabilities of its nanocellulose to construct a micro-network buffer layer at the endosperm-germ-branch interface. Low-temperature, low-speed differential milling is implemented to reduce structural breakage. Defatted germ powder is selectively added back from the bran core stream to compensate for nutrients. The addition of organic acid salt buffers and soluble calcium salts stabilizes the pH and provides calcium. 2+ Bridging, while ensuring processability, increases the content of wheat germ dietary fiber and kombucha dietary fiber in flour, and simultaneously inhibits ionic strength fluctuations and gluten protein oxidative cross-linking through pH buffering. 2+ Improve the toughness of flour products, reduce breakage rate, and extend shelf life. Attached Figure Description

[0036] Figure 1 This is a flowchart of the wheat germ dietary fiber content determination process of the present invention;

[0037] Figure 2 This is a flowchart illustrating the process of obtaining dietary fiber from kombucha according to the present invention.

[0038] Figure 3 Box plot of flour performance index test records for this invention;

[0039] Figure 4 Box plot of the performance test record of noodles made from the flour of this invention;

[0040] Figure 5 This is a flowchart of the flour production method of the present invention. Detailed Implementation

[0041] 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.

[0042] Example 1

[0043] This invention proposes a nutritious flour rich in wheat germ and dietary fiber, comprising, by weight, 80-94 parts of wheat flour conforming to GB / T1355-2021, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber, and 12-14.5 parts of water. The wheat germ dietary fiber includes neutral detergent fiber and acid detergent fiber from wheat germ, measured using a combination of methods from GB / T5009.10 and GB / T5009.88. The kombucha dietary fiber is obtained by washing, neutralizing, dehydrating, and drying bacterial cellulose from a black tea fermentation system. It has an average fiber diameter of 0.02-0.15 μm, a length of 1-50 μm, and a water absorption value ≥8 g / g, and coexists with the wheat dietary fiber at a weight ratio of 2:1 to 8:1.

[0044] According to GB / T1355-2021, wheat flour + wheat germ dietary fiber + kombucha dietary fiber, with a controlled coexistence ratio of 2:1 to 8:1, is used to form a permeable, water-retaining, and adhesive micro-network composite fiber phase during the powder and dough mixing process. The principle is that wheat germ dietary fiber provides a rigid framework and nutrient source, but when present alone, it is easily broken and unevenly dispersed under milling / sieving and dough shearing. Kombucha dietary fiber, with an average diameter of 0.02–0.15 μm and a water absorption value ≥8 g / g, has a large specific surface area. Strong hydrophilicity and film-forming properties enable physical bridging and capillary water retention at the endosperm-germ-bran interface and between gluten and starch granules, reducing secondary breakage and loss of germ fibers caused by subsequent shearing, and inhibiting free water leakage and starch retrogradation. When the two reach the percolation threshold in the specified ratio, the composite network forms a three-phase synergy with gluten in the dough (protein-wheat germ dietary fiber-kombucha dietary fiber), improving the water absorption capacity, extensibility, and stability time of the dough made from this flour, while reducing flour quality fluctuations caused by germ lipid migration. While ensuring 100-mesh sieve passability and processability, this flour improves the retention and uniformity of high germ dietary fiber, enhances dough water retention and texture, and improves the overall scores of flour products in terms of color, smoothness, softness, and taste, while also contributing to shelf-life stability.

[0045] It should be noted that the wheat dietary fiber is composed of two types of flour blended in a mass ratio of 40:60 to 60:40: the first type of flour is wheat germ flour that has undergone a combination of cold-pressed defatting and supercritical carbon dioxide defatting; the second type of flour is wheat cell wall dietary fiber obtained by roller milling, which is extracted by enzymatic desaturation and alkali-soluble acid precipitation, and then precipitated with 60% to 80% volume fraction ethanol, desalted, and dried at 40℃ to 55℃; the total mass of wheat germ dietary fiber after blending the two types of flour accounts for ≥60% of the total mass of the blended flour.

[0046] Wheat germ dietary fiber is compounded from two sources in a ratio of 40:60 to 60:40. The two sources are then used: one for cold pressing and supercritical CO2 defatting to obtain low-fat germ powder with higher oxidative stability, and the other for enzymatic hydrolysis of germ to remove starch, followed by alkali dissolution, acid precipitation, and desalting with 60%–80% ethanol, and drying at 40–55°C to obtain cell wall-rich fiber. This process aims to form a micro-network framework with a rigid cell wall and flexible polysaccharide hierarchy, while ensuring a total dietary fiber content of ≥60%. It also considers the synergy of particle size and specific surface area to improve dispersibility and hydrophilic water retention, enhance adhesion and bridging with gluten and starch, and inhibit lipid-induced rancidity. This improves the retention rate and uniformity of germ fiber throughout the entire process of milling, blending, and dough mixing, improves dough water absorption, stability time, and extensibility, reduces breakage and quality fluctuations, and extends shelf life. Furthermore, the physicochemical fingerprints of the two sources facilitate batch-to-batch consistency verification using neutral and acidic detergent fibers, residual fat, and particle size distribution in wheat germ.

[0047] It should be noted that the process for determining the content of dietary fiber in wheat germ using a combination of GB / T5009.10 and GB / T5009.88 methods includes:

[0048] Step 11: Pre-treat the sample according to GB5009.88, and enzymatically hydrolyze it with heat-resistant α-amylase, protease and glucoamylase at the specified pH and temperature to remove digestible starch and protein, and remove oligomeric soluble components by ethanol precipitation to obtain enzyme-treated residue.

[0049] Step 12: Extract the residue obtained in step 11 using the neutral detergent method described in GB5009.88. After filtration, drying at 105°C, scalding, and blank deduction of protein and ash content, calculate the dry basis of the neutral detergent fiber in g / g.

[0050] Step 13: The filter residue obtained in Step 12 is further subjected to acid washing. Referring to the acid treatment intensity and operation points specified in GB / T 5009.10, the specified acid detergent is used to treat the residue under constant temperature reflux conditions to dissolve and remove acid-soluble components such as hemicellulose. Then, the residue is filtered, dried at 105℃ and ashed, and protein and ash content are deducted and reagent blank is corrected. The dry basis of the acid-washed fiber is calculated in g / g.

[0051] Step 14: The total amount of neutral detergent fiber and acid detergent fiber in wheat germ is taken as the dietary fiber content of wheat germ, and is expressed as the average of two parallel measurements.

[0052] Step 15: If the fat content of the dry sample is >5%, it should be degreased according to the standard before measurement.

[0053] The combined assay procedure of GB / T5009.10 and GB / T5009.88 was adopted. Digestible starch and protein were fully removed by enzymatic pretreatment and oligomeric solubles were removed by ethanol precipitation. NDF and ADF were then extracted under constant conditions by neutral washing and acid washing, respectively, and protein, ash and reagent blank were deducted. This allows the sum of neutral washed fiber and acid washed fiber to obtain highly selective and comparable quantitative results under dry basis and defatting conditions. It avoids positive bias interference of residual starch, protein and lipids on mass fraction, and improves repeatability and batch consistency through parallel retesting and tolerance control. Finally, it provides accurate, stable and traceable test basis for formula consistency judgment, process parameter backtracking and quality release.

[0054] It should be noted that the process of obtaining dietary fiber from kombucha includes:

[0055] Step 21, Preparation of raw materials and black tea base: Take drinking-grade water, add black tea at 0.5% to 1.0% m / V, boil and steep for 5 to 10 minutes, filter to obtain tea liquor, add sucrose at 6% to 10% m / V while hot and dissolve, cool to 25 to 30°C, add yeast extract powder at 0.1% to 0.3% m / V as needed, pour the tea liquor into a fermentation pan, with a liquid depth of 2 to 6 cm, and sterilize at 121°C for 15 minutes;

[0056] Step 22, Inoculation and Static Fermentation: Under aseptic conditions, inoculate with kombucha symbiotic liquid, which contains bacterial film and fermentation liquid. The inoculation amount is 10% to 30% V / V, the pH is adjusted to 5.0 to 5.6, and the mixture is allowed to stand at 25 to 30°C for 7 to 14 days to form a dense bacterial cellulose film on the liquid surface. During this period, the pH and film thickness are recorded daily.

[0057] Step 23, membrane removal and pre-washing: Remove the bacterial membrane, remove the attached fermentation liquid, and gently rinse with running drinking water until the surface is no longer sticky and the odor is significantly reduced. If necessary, quickly soak in 1% V / V food-grade acetic acid aqueous solution for 5-10 minutes to decolorize and remove odor, and then rinse with water.

[0058] Step 24, alkaline washing to remove impurities: Place the pre-washed membrane strips in 0.1% to 1.0% m / V NaOH solution and treat at 60 to 90°C for 30 to 120 minutes, stirring gently during the process. After pouring out the alkaline solution, wash repeatedly with warm water until the washing solution is close to neutral pH, colorless and foam-free.

[0059] Step 25, Neutralization and fine washing: Adjust the pH of the cellulose after alkali washing to 6.0 to 6.8 with 0.05% to 0.5% m / V food-grade organic acid, let it stand for 10 to 30 minutes, then rinse with drinking water until the pH is 6.0 to 7.0 and the conductivity is close to the background value of the incoming water, and then wash it thoroughly.

[0060] Step 26, Mechanical dehydration and drying into fibers: The purified wet film is sheared and pulped at 3000-8000 rpm for 1-3 minutes to obtain a uniform slurry. The slurry is then centrifuged at 3000-6000 g for 5-10 minutes until the moisture content reaches 60%-75%. The slurry is pre-frozen at -40℃ for 2-4 hours and then freeze-dried under vacuum for 12-24 hours. The dried product is then pulverized by air jet milling at a low temperature (temperature controlled below 45℃) and sieved to obtain kombucha dietary fiber of the target particle size.

[0061] It should be noted that in step 26, the target particle size of kombucha dietary fiber includes 1-30 μm for the dispersion and 50-150 μm for the powder. The kombucha dietary fiber has a moisture content of ≤7.0% by mass, an ash content of ≤1.0% by mass, a pH of 6.0-7.0, and a microbial content that meets the food control requirements.

[0062] This invention classifies kombucha dietary fiber according to particle size: fine particles of 1-30μm are used to prepare a pre-dispersant for wheat gluten, which, due to its high specific surface area and easy redispersibility, forms a coating or bridging micro-network at the endosperm-germ-branch interface, enhancing water retention and viscoelasticity, buffering mill shearing, and promoting uniform binding of gluten and starch; coarse particles of 50-150μm are added dry during the powder preparation stage, serving as a compressible structural framework and a sponge-like slow-release carrier, working with germ fibers to construct a hierarchical porous network, improving extensibility and stability, reducing breakage and cloudiness, and improving taste and shelf stability; within the range of kombucha fiber:germ fiber 2:1 to 8:1, the fine particles act as an adhesive / coating and the coarse particles as a support / filler, synergistically inhibiting oxidation and agglomeration, facilitating batch powder preparation and storage, and balancing processability, nutrient retention, and quality consistency.

[0063] It should be noted that the flour also includes 0.05 to 0.30 parts by weight of food-grade organic acid salt buffer, which includes one or two of sodium citrate, potassium sodium tartrate, or sodium malate.

[0064] Adding 0.05–0.30 parts of sodium citrate / sodium potassium tartrate / sodium malate buffer to the flour system can stabilize the pH at 6.0–6.8 during the kneading and kombucha fiber dispersion stages, reduce abrupt changes in ionic strength, improve the redispersibility and short-term stability of bacterial cellulose, inhibit quality fluctuations caused by excessive oxidative cross-linking of gluten protein and germ lipolysis, promote the synergistic effect of protein-starch-fiber and water binding, reduce dough viscosity fluctuations, improve water absorption and extensibility stability, reduce noodle breakage and texture dispersion in noodles made with this flour, enhance batch consistency, and contribute to shelf-life safety.

[0065] It should be noted that the flour also includes 0.05 to 0.20 parts by weight of food-grade soluble calcium salt, which includes one of calcium citrate, calcium lactate, or calcium hydrogen phosphate.

[0066] Adding 0.05–0.20 parts of soluble calcium salts (calcium citrate / calcium lactate / calcium hydrogen phosphate) to flour releases Ca... 2+ During the dough kneading process, it forms ionic bridges with the carboxyl / hydroxyl groups on the surface of kombucha fiber and wheat germ dietary fiber, and forms dot-like coordination with the side chains of gluten protein, thus constructing a denser fiber-protein-synergistic network. This improves the dough's water retention and viscoelasticity, extensibility and shear resistance, reduces breakage and cooking loss, improves the texture and elasticity, inhibits quality fluctuations, and enhances batch consistency and shelf-life stability.

[0067] The following samples were used as follows: flour (as proposed in this invention) as sample 1; wheat flour conforming to GB / T1355-2021 as sample 2; flour without kombucha dietary fiber powder as sample 3; flour without kombucha dietary fiber dispersion as sample 4; flour without added wheat germ dietary fiber as sample 5; and flour without food-grade soluble calcium salts and without food-grade organic acid salt buffers as sample 6. Performance indicators of the flour and noodle products were tested respectively. For each sample, 20 samples were randomly selected from 100 data sets, and their averages were recorded. The test data are shown in Table 1, and the box plot is shown below. Figure 3 and Figure 4 As shown:

[0068] Table 1 Flour Performance Test Record Sheet

[0069] Index / Explanation Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 [Flour] moisture (%) average 12.984 13.116 13.002 13.056 13.035 12.976 [Flour] moisture (%) standard deviation 0.303 0.235 0.308 0.395 0.263 0.419 [Flour] ash (%) average 0.594 0.536 0.6 0.601 0.484 0.595 [Flour] ash (%) standard deviation 0.056 0.047 0.06 0.062 0.045 0.052 [Flour] fatty acid value (mgKOH / 100g) average 19.732 17.418 20.159 21.797 18.575 22.081 [Flour] fatty acid value (mgKOH / 100g) standard deviation 2.538 1.734 2.572 2.64 2.184 2.518 [Flour] 100 mesh sieve passing rate (%) average 87.875 89.864 87.847 85.205 89.797 85.567 [Flour] 100 mesh sieve passing rate (%) standard deviation 2.407 1.984 1.894 2.841 1.552 3.145 [Flour] wet gluten (%) average 28.94 27.387 29.732 27.87 27.491 27.947 [Flour] wet gluten (%) standard deviation 1.968 2.115 2.2 1.869 2.453 1.858 [Flour] water absorption rate (%) average 60.798 58.163 60.005 60.137 58.741 58.938 [Flour] water absorption rate (%) standard deviation 1.984 1.169 1.757 1.557 1.617 1.936 [Flour] stabilization time (min) average 5.196 4.27 4.636 4.57 4.171 4.254 [Flour] stabilization time (min) standard deviation 0.782 0.718 0.873 0.691 0.673 0.848 [Flour] water activity aw average 0.545 0.551 0.543 0.547 0.554 0.567 [Flour] water activity aw standard deviation 0.024 0.018 0.02 0.02 0.015 0.014 [Flour] total number of colonies (CFU / g) average 3146.4 3151.5 3050.7 3228.3 2641.9 3364.5 [Flour] total number of colonies (CFU / g) standard deviation 857.2 887.3 897.3 910.1 773.8 1004.3 [Noodle] cooking loss rate (%) average 6.132 7.634 6.601 7.14 7.303 6.843 [Noodle] cooking loss rate (%) standard deviation 0.883 0.886 0.892 1.232 1.167 0.77 [Noodle] breaking rate (%) average 2.174 4.831 3.67 3.16 3.642 4.659 [Noodle] breaking rate (%) standard deviation 1.189 2.69 1.346 1.521 1.495 1.657 [Noodle] tensile force (N) average 1.81 1.47 1.633 1.691 1.573 1.595 [Noodle] tensile force (N) standard deviation 0.172 0.161 0.196 0.196 0.174 0.24 [Noodle] hardness (gf) average 5163.9 4725.9 5035.3 5152.1 5033.9 4952.9 [Noodle] hardness (gf) standard deviation 446.15 536.25 609.91 430.68 565.86 591.00

[0070] As shown in Table 1, compared with Sample 2 (a control of wheat flour that only meets GB / T1355-2021 standards), Samples 1, 3, 4, 5, and 6 generally exhibit advantages in processing and edible quality: Sample 1 (the solution of this invention) has higher water absorption and stability time, lower breakage rate and cooking loss rate, greater tensile strength, and more stable taste, while fatty acid value and microbial content are also within the controlled range; Samples 3 (without kombucha fiber powder) and 4 (without kombucha fiber dispersion) have improved compared to Sample 2, but their stability time, breakage rate, and taste are inferior to Sample 1; Sample 5 (without added germ dietary fiber) shows a shortcoming of insufficient synergy between nutrition and texture; Sample 6 (without calcium salts and buffers) is inferior to Sample 1 in terms of stability, breakage, and fatty acid value fluctuation. Further comparison of Sample 1 with Samples 3, 4, 5, and 6 reveals that: the dual-form division of kombucha fiber (fine-particle dispersion for wheat nourishment + coarse-particle dry powder for powder preparation) jointly ensures the synergistic effect of shear buffering, water retention, and bridging coating; the addition of germ dietary fiber is key to enhancing the synergistic effect of nutrition and skeletal structure; and soluble calcium salts provide Ca... 2+ Bridging and organic acid salt buffers stabilize pH and ionic strength, and together they reduce batch-to-batch fluctuations and consolidate texture and shelf stability, ultimately resulting in the optimal overall performance shown in Sample 1.

[0071] Example 2

[0072] The difference between Embodiment 2 and Embodiment 1 is that this embodiment describes a method for producing a nutritious flour rich in wheat germ and dietary fiber.

[0073] like Figure 5As shown, the present invention proposes a method for producing a nutritious flour rich in wheat germ and dietary fiber, used to produce the nutritious flour rich in wheat germ and dietary fiber described in Example 1, comprising the following steps:

[0074] Step S1, Raw grain cleaning and grading: Airflow gravity and magnetic separation are used together to remove impurities from the raw grain, and the impurity content is controlled to be ≤1%. Grading is carried out according to particle size and bulk density.

[0075] Step S2, preparation of kombucha dietary fiber dispersion: Take dry powder kombucha dietary fiber with a target particle size of 1-30 μm, add drinking water at a solid-liquid ratio of 1:20-1:40 m / V, and shear at high speed of 8000-15000 rpm for 3-10 min to obtain a uniform dispersion. Add food-grade organic acid salt buffer to the main powder stream in the direction of preparation, and adjust the pH to 6.0-6.8 to prepare kombucha dietary fiber dispersion;

[0076] Step S3, Wheat conditioning: Spray the raw wheat grains with the kombucha dietary fiber dispersion obtained in step S2 and water to adjust the moisture content of the wheat grains to 15.0% to 17.0%, and let them stand at room temperature for 12 to 24 hours;

[0077] Step S4, temperature-controlled roller mill crushing: multi-stage roller mill, controlling the roller temperature ≤35℃ and the linear speed difference 1.2~2.5rpm, and recording energy consumption and powder output rate in real time;

[0078] Step S5, sieving and purification: According to the powder path configuration, perform grading sieving and cleaning, collect the main powder flow, bran secondary flow, and bran core secondary flow, and monitor online to ensure that the 100-mesh sieve passing rate is ≥85% and the fatty acid value meets the preset requirements;

[0079] Step S6, adding back and adjusting the proportion of wheat germ fine powder: Select wheat germ fine powder from the bran core stream, dry it with hot air at 40-55℃ until the moisture content is ≤7.0%, pass it through a 100-mesh sieve and ≥90%, and then add it back to the main powder according to the target nutrient setting to achieve the total target of 3-12 parts by weight of wheat germ dietary fiber.

[0080] Step S7, synergistic addition of calcium salt: Add food-grade soluble calcium salt to the mixed powder in the direction of mixing. The average particle size of the food-grade soluble calcium salt is 3-8 μm, and the mass ratio of the calcium salt to kombucha fiber is 0.05:1-0.3:1.

[0081] Step S8, Metering and Homogenization: Add 80-94 parts of wheat flour conforming to GB / T1355-2021, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber, food-grade organic acid salt buffer, and food-grade soluble calcium salt to a high-speed horizontal mixer by mass, and homogenize at low temperature for 3-8 minutes, with the material outlet temperature rise ≤5℃;

[0082] Step S9, Moisture calibration and stabilization: Using atomized water replenishment or low-temperature ventilation, adjust the moisture content of the finished product to 12.0-14.5 parts by weight, let it stand for 4-12 hours to equalize, and check the flour indicators according to the preset test items while conducting standard flour testing. After verifying that it meets the standards, release it and package the finished product in nitrogen-filled light-proof composite bags.

[0083] Through the synergistic application of processes S1 to S9, kombucha dietary fiber is placed in a fine-particle dispersion at the endosperm-germ-bran interface before wheat conditioning to construct an adhesive buffer micro-network. This, combined with temperature-controlled low-shear milling and online sieving / fatty acid value monitoring, reduces secondary breakage and loss of germ fiber with the bran. Furthermore, the addition of germ powder, organic acid salt buffers to stabilize the pH, and soluble calcium salts to provide calcium are then employed. 2+ The bridging process ensures that the germ fiber and kombucha fiber content in the flour meets the standards and is evenly distributed, improves water absorption and stability time, reduces breakage and cooking loss, inhibits fat oxidation and quality fluctuations, and balances processability, shelf life and batch consistency, while meeting microbiological and physicochemical safety release requirements.

[0084] It should be noted that in step S6, the amount of germ powder added back accounts for 2 to 8 parts of the finished product mass.

[0085] In S6, the germ powder is added back at 2 to 8 parts of the finished product. Without increasing fat and causing spoilage, it effectively replenishes germ dietary fiber and micronutrients. It works synergistically with kombucha fiber to build a skeleton-adhesion network, improves water absorption and stability time, uniformity and toughness, reduces breakage and quality fluctuations, and enhances batch-to-batch consistency.

[0086] It should be noted that in step S9, the preset detection items include the determination of the dietary fiber content of kombucha in the finished flour and the determination of the dietary fiber content of wheat germ.

[0087] By quantitatively testing the kombucha dietary fiber and wheat germ dietary fiber in the finished product using S9, the consistency of the formula and content can be verified, supporting closed-loop correction of powder mixing and refilling, reducing batch-to-batch fluctuations, and ensuring controlled processes, stable quality, and traceable release.

[0088] In summary, this invention introduces kombucha dietary fiber dispersion during the wheat-rehydration stage, utilizing its hydrophilic, film-forming, and adhesive bridging capabilities of nanocellulose to construct a micro-mesh buffer layer at the endosperm-germ-branch interface. Low-temperature, low-speed differential milling is employed to reduce structural breakage. Defatted germ powder is selectively added back from the bran core stream to compensate for nutritional deficiencies. Organic acid salt buffers and soluble calcium salts are added to stabilize pH and provide calcium. 2+ Bridging, while ensuring processability, increases the content of wheat germ dietary fiber and kombucha dietary fiber in flour, and simultaneously inhibits ionic strength fluctuations and gluten protein oxidative cross-linking through pH buffering. 2+ Improve the toughness of flour products, reduce breakage rate, and extend shelf life.

[0089] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0090] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nutritious flour rich in wheat germ and dietary fiber, characterized in that, The product comprises, by weight, 80–94 parts wheat flour conforming to GB / T1355-2021, 3–12 parts wheat germ dietary fiber, 1–6 parts kombucha dietary fiber, and 12–14.5 parts moisture. The wheat germ dietary fiber includes neutral detergent fiber and acid detergent fiber from wheat germ, and is measured using a combination of methods from GB / T5009.10 and GB / T5009.

88. The kombucha dietary fiber is obtained by washing, neutralizing, dehydrating, and drying bacterial cellulose from a black tea fermentation system. It has an average fiber diameter of 0.02–0.15 μm, a length of 1–50 μm, and a water absorption value ≥8 g / g. It coexists with wheat dietary fiber at a weight ratio of 2:1 to 8:

1.

2. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 1, characterized in that, Wheat dietary fiber is composed of two types of flour blended in a mass ratio of 40:60 to 60:40: one type of flour is wheat germ flour that has undergone a combination of cold-pressed defatting and supercritical carbon dioxide defatting; the other type of flour is wheat cell wall dietary fiber obtained by roller milling, which is extracted by enzymatic desaturation and alkali-soluble acid precipitation, followed by precipitation with 60%–80% volume fraction ethanol, desalting, and drying at 40℃–55℃; the total mass of wheat germ dietary fiber after blending accounts for ≥60% of the total flour mass.

3. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 1, characterized in that, The process for determining the content of dietary fiber in wheat germ using a combination of GB / T5009.10 and GB / T5009.88 methods includes: Step 11: Pre-treat the sample according to GB5009.88, and enzymatically hydrolyze it with heat-resistant α-amylase, protease and glucoamylase at the specified pH and temperature to remove digestible starch and protein, and remove oligomeric soluble components by ethanol precipitation to obtain enzyme-treated residue. Step 12: Extract the residue obtained in step 11 using the neutral detergent method described in GB5009.

88. After filtration, drying at 105°C, scalding, and blank deduction of protein and ash content, calculate the dry basis of the neutral detergent fiber in g / g. Step 13: The filter residue obtained in Step 12 is further subjected to acid washing. Referring to the acid treatment intensity and operation points specified in GB / T 5009.10, the specified acid detergent is used to treat the residue under constant temperature reflux conditions to dissolve and remove acid-soluble components such as hemicellulose. Then, the residue is filtered, dried at 105℃ and ashed, and protein and ash content are deducted and reagent blank is corrected. The dry basis of the acid-washed fiber is calculated in g / g. Step 14: The total amount of neutral detergent fiber and acid detergent fiber in wheat germ is taken as the dietary fiber content of wheat germ, and is expressed as the average of two parallel measurements. Step 15: If the fat content of the dry sample is >5%, it should be degreased according to the standard before measurement.

4. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 1, characterized in that, The process of obtaining dietary fiber from kombucha includes: Step 21, Preparation of raw materials and black tea base: Take drinking-grade water, add black tea at 0.5% to 1.0% m / V, boil and steep for 5 to 10 minutes, filter to obtain tea liquor, add sucrose at 6% to 10% m / V while hot and dissolve, cool to 25 to 30°C, add yeast extract powder at 0.1% to 0.3% m / V as needed, pour the tea liquor into a fermentation pan, with a liquid depth of 2 to 6 cm, and sterilize at 121°C for 15 minutes; Step 22, Inoculation and Static Fermentation: Under aseptic conditions, inoculate with kombucha symbiotic liquid, which contains bacterial film and fermentation liquid. The inoculation amount is 10% to 30% V / V, the pH is adjusted to 5.0 to 5.6, and the mixture is allowed to stand at 25 to 30°C for 7 to 14 days to form a dense bacterial cellulose film on the liquid surface. During this period, the pH and film thickness are recorded daily. Step 23, membrane removal and pre-washing: Remove the bacterial membrane, remove the attached fermentation liquid, and gently rinse with running drinking water until the surface is no longer sticky and the odor is significantly reduced. If necessary, quickly soak in 1% V / V food-grade acetic acid aqueous solution for 5-10 minutes to decolorize and remove odor, and then rinse with water. Step 24, alkaline washing to remove impurities: Place the pre-washed membrane strips in 0.1% to 1.0% m / V NaOH solution and treat at 60 to 90°C for 30 to 120 minutes, stirring gently during the process. After pouring out the alkaline solution, wash repeatedly with warm water until the washing solution is close to neutral pH, colorless and foam-free. Step 25, Neutralization and fine washing: Adjust the pH of the cellulose after alkali washing to 6.0 to 6.8 with 0.05% to 0.5% m / V food-grade organic acid, let it stand for 10 to 30 minutes, then rinse with drinking water until the pH is 6.0 to 7.0 and the conductivity is close to the background value of the incoming water, and then wash it thoroughly. Step 26, Mechanical dehydration and drying into fibers: The purified wet film is sheared and pulped at 3000-8000 rpm for 1-3 minutes to obtain a uniform slurry. The slurry is then centrifuged at 3000-6000 g for 5-10 minutes until the moisture content reaches 60%-75%. The slurry is pre-frozen at -40℃ for 2-4 hours and then freeze-dried under vacuum for 12-24 hours. The dried product is then pulverized by air jet milling at a low temperature (temperature controlled below 45℃) and sieved to obtain kombucha dietary fiber of the target particle size.

5. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 4, characterized in that, In step 26, the target particle size of kombucha dietary fiber includes 1-30 μm for dispersion and 50-150 μm for powder preparation, wherein the kombucha dietary fiber has a moisture content of ≤7.0% by mass, an ash content of ≤1.0% by mass, a pH of 6.0-7.0, and a microbial content that meets the food control requirements.

6. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 1, characterized in that, The flour also includes 0.05 to 0.30 parts by weight of food-grade organic acid salt buffer, which includes one or two of sodium citrate, potassium sodium tartrate, or sodium malate.

7. The nutritional flour rich in wheat germ and high in dietary fiber according to claim 1, characterized in that, The flour also includes 0.05 to 0.20 parts by weight of food-grade soluble calcium salt, which includes one of calcium citrate, calcium lactate, or calcium hydrogen phosphate.

8. A method for producing a nutritious flour rich in wheat germ and dietary fiber, used to produce the nutritious flour rich in wheat germ and dietary fiber as described in any one of claims 1-7, characterized in that... The process includes the following steps: Step S1, Raw grain cleaning and grading: Airflow gravity and magnetic separation are used together to remove impurities from the raw grain, and the impurity content is controlled to be ≤1%. Grading is carried out according to particle size and bulk density. Step S2, preparation of kombucha dietary fiber dispersion: Take dry powder kombucha dietary fiber with a target particle size of 1-30 μm, add drinking water at a solid-liquid ratio of 1:20-1:40 m / V, and shear at high speed of 8000-15000 rpm for 3-10 min to obtain a uniform dispersion. Add food-grade organic acid salt buffer to the main powder stream in the direction of preparation, and adjust the pH to 6.0-6.8 to prepare kombucha dietary fiber dispersion; Step S3, Wheat conditioning: Spray the raw wheat grains with the kombucha dietary fiber dispersion obtained in step S2 and water to adjust the moisture content of the wheat grains to 15.0% to 17.0%, and let them stand at room temperature for 12 to 24 hours; Step S4, temperature-controlled roller mill crushing: multi-stage roller mill, controlling the roller temperature ≤35℃ and the linear speed difference 1.2~2.5rpm, and recording energy consumption and powder output rate in real time; Step S5, sieving and purification: According to the powder path configuration, perform grading sieving and cleaning, collect the main powder flow, bran secondary flow, and bran core secondary flow, and monitor online to ensure that the 100-mesh sieve passing rate is ≥85% and the fatty acid value meets the preset requirements; Step S6, adding back and adjusting the proportion of wheat germ fine powder: Select wheat germ fine powder from the bran core stream, dry it with hot air at 40-55℃ until the moisture content is ≤7.0%, pass it through a 100-mesh sieve and ≥90%, and then add it back to the main powder according to the target nutrient setting to achieve the total target of 3-12 parts by weight of wheat germ dietary fiber. Step S7, synergistic addition of calcium salt: Add food-grade soluble calcium salt to the mixed powder in the direction of mixing. The average particle size of the food-grade soluble calcium salt is 3-8 μm, and the mass ratio of the calcium salt to kombucha fiber is 0.05:1-0.3:

1. Step S8, Metering and Homogenization: Add 80-94 parts of wheat flour conforming to GB / T1355-2021, 3-12 parts of wheat germ dietary fiber, 1-6 parts of kombucha dietary fiber, food-grade organic acid salt buffer, and food-grade soluble calcium salt to a high-speed horizontal mixer by mass, and homogenize at low temperature for 3-8 minutes, with the material outlet temperature rise ≤5℃; Step S9, Moisture calibration and stabilization: Using atomized water replenishment or low-temperature ventilation, adjust the moisture content of the finished product to 12.0-14.5 parts by weight, let it stand for 4-12 hours to equalize, and check the flour indicators according to the preset test items while conducting standard flour testing. After verifying that it meets the standards, release it and package the finished product in nitrogen-filled light-proof composite bags.

9. The method for producing a nutritious flour rich in wheat germ and dietary fiber according to claim 8, characterized in that, In step S6, the amount of germ powder added back accounts for 2 to 8 parts by weight of the finished product.

10. The method for producing a nutritious flour rich in wheat germ and dietary fiber according to claim 8, characterized in that, In step S9, the preset detection items include the determination of kombucha dietary fiber content and wheat germ dietary fiber content in the finished flour.

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