High-purity oat beta-glucan frozen dough as well as preparation method and application thereof

Abstract

The invention discloses high-purity oat beta-glucan frozen dough as well as a preparation method and application thereof, and belongs to the technical field of food processing and freezing. The preparation method comprises the following steps: mixing medium gluten wheat flour and self-made oat beta-glucan according to a specific ratio, kneading, fermenting, quickly freezing, freezing and storing, and the like, so as to prepare the frozen dough. The self-made oat beta-glucan is added, so that the anti-freezing performance, gluten network stability and yeast activity protection capability of frozen dough are remarkably improved, and meanwhile, the nutritional characteristics and sensory quality of the finished steamed buns are improved. The method solves the problems that existing frozen dough is insufficient in freezing resistance and poor in long-term freezing storage stability, and has high application value and market prospects.

Description

Technical Field

[0001] This invention belongs to the field of food processing and freezing technology, specifically relating to a high-purity oat β-glucan frozen dough, its preparation method, and its application. Background Technology

[0002] Frozen dough technology has been widely used in modern food industry due to its advantages such as high efficiency, immediacy, and consistent quality. However, during the freezing process, dough is prone to problems such as poor rise, poor recovery, and a dry, hard core, leading to a decline in the quality of the finished product. To solve these problems, existing technologies mostly employ the addition of antifreeze agents or improvers to mitigate the damage to the dough's structure and properties caused by freezing. However, the application of oat β-glucan in frozen dough has not yet been systematically reported, and existing technologies still have certain limitations in improving the quality of frozen dough.

[0003] A search revealed a method for preparing type III buckwheat sourdough with antifreeze properties, published on February 20, 2024, with publication number CN112956508B. This patent improves the antifreeze and fermentation properties of frozen dough by adding a compound antifreeze modifier and ice structural proteins to the sourdough, thereby lowering the dough's crystallization temperature and reducing the damage of ice crystal particles to lactic acid bacteria and yeast. However, this technical solution is primarily aimed at sourdough systems, and its modifier formulation and process conditions may not be applicable to ordinary frozen dough systems. Furthermore, the specific composition of the compound antifreeze modifier is not detailed, which may limit its adaptability and effectiveness in practical applications.

[0004] A search revealed a method for preparing freeze-thaw resistant pre-made semi-proofed Chinese-style frozen dough, publication number CN116035165B, published on January 21, 2025. This patent effectively solves problems such as shrinkage, cracking, discoloration, and poor taste that occur in frozen dough after repeated freeze-thaw cycles by adding ice structural proteins and konjac glucomannan, and also supplements some functional components. However, this technical solution has a relatively limited selection of antifreeze agents and mainly relies on the effect of ice structural proteins, which may be insufficient in maintaining antifreeze performance under long-term frozen storage conditions. In addition, this solution has limited protection measures for yeast activity, which may affect the fermentation performance of the frozen dough and the quality of the final product.

[0005] The above problems indicate that existing frozen dough improvement technologies still have certain shortcomings in terms of antifreeze performance, yeast activity protection, and long-term frozen storage stability. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing frozen dough containing oat β-glucan. The aim is to utilize the strong hydrophilicity and cross-linking properties of oat β-glucan to improve the rheological and thermal stability of the dough, enhance the storage stability of the frozen dough, and simultaneously improve the nutritional characteristics of the finished product as dietary fiber, thereby meeting the demands of the modern food industry for high-quality frozen dough.

[0007] This invention provides a method for preparing antifreeze dough using homemade oat β-glucan. The aim is to improve the antifreeze properties, gluten network stability, and yeast activity protection of frozen dough by adding homemade oat β-glucan under specific proportions and processing conditions, while simultaneously enhancing the nutritional characteristics of the finished dough products. Oat β-glucan is abbreviated as OβG, and the oat β-glucan and OβG mentioned below refer to the same substance.

[0008] In a first aspect, the present invention provides a method for preparing frozen dough containing homemade oat β-glucan, comprising the following steps:

[0009] S10: Mix medium-gluten wheat flour with homemade oat β-glucan evenly to obtain a mixed powder;

[0010] S20: Dissolve dry yeast in water to obtain a yeast solution;

[0011] S30: Mix the above-mentioned powder with the yeast solution and knead by hand until the dough surface is smooth to obtain the initial dough;

[0012] S40: Ferment the initial dough for a period of time to allow the dough to form a complete porous structure.

[0013] S50: The fermented dough is kneaded by hand to remove internal air pockets, sealed with plastic wrap and quick-frozen; then frozen and stored to obtain frozen dough.

[0014] In this invention, by adding homemade oat β-glucan to medium-gluten wheat flour, its strong hydrophilicity and cross-linking properties significantly reduce the content of freezeable water during freezing, minimizing the damage of ice crystals to the gluten protein structure, thereby stabilizing the gluten network and protein secondary structure. Furthermore, the homemade oat β-glucan can inhibit ice crystal distribution and crystal size, maintaining the integrity of the frozen dough's microstructure and exhibiting excellent stability under long-term frozen storage conditions.

[0015] In some embodiments, in step S10, the mass ratio of medium-gluten wheat flour to homemade oat β-glucan is (95-99):(1-5).

[0016] In some embodiments, in step S10, the amount of the homemade oat β-glucan added relative to the mixed powder is preferably 5%. Under this condition, the hardness, elasticity and gas-holding capacity of the frozen dough can be significantly improved, while the yeast activity remains unaffected.

[0017] In some embodiments, the homemade oat β-glucan has a weight-average molecular weight ranging from 150,000 to 300,000 Daltons and has a loose granular structure.

[0018] In some embodiments, the homemade oat β-glucan has the following composition: moisture content 7.81% ± 0.05%, ash content 10.94% ± 0.15%, total sugar content 71.94% ± 1.18%, total phenol content 1.06% ± 0.02%, protein content 4.91% ± 0.07%, uronic acid content 2.64% ± 0.04%, reducing sugar content 7.45% ± 0.23%, and β-glucan content 63.14% ± 0.16%.

[0019] In some embodiments, step S10, the method for preparing the homemade oat β-glucan includes the following steps:

[0020] M1: Oat bran is crushed into powder with a particle size of 100 to 200 micrometers and mixed with distilled water to prepare a suspension with a mass fraction of 10% to 15%.

[0021] M2: Add an alkaline substance to the above suspension to adjust the pH value to 9 to 10, heat to 50 degrees Celsius to 60 degrees Celsius and stir to extract for 2 to 3 hours;

[0022] M3: After cooling the extract to room temperature, centrifuge to separate the extract, take the supernatant and add ethanol to precipitate, and obtain the crude extract;

[0023] M4: The crude extract was dissolved in water and filtered through an ultrafiltration membrane to retain components with a molecular weight range of 150,000 to 300,000 Daltons. After freeze-drying, the self-made oat β-glucan was obtained.

[0024] In some embodiments, in step M2, the alkaline substance is sodium hydroxide or sodium carbonate, and the amount used is 5 to 10 grams per liter of suspension.

[0025] In some embodiments, in step M3, the amount of ethanol added is 2 to 3 times the volume of the extract.

[0026] In some embodiments, in step M4, the ultrafiltration membrane has a pore size of 10,000 to 50,000 Daltons and an operating pressure of 0.1 MPa to 0.3 MPa.

[0027] In some embodiments, in step S20, the dry yeast is dispersed in warm water at 37°C to 40°C and stirred until completely dissolved to obtain a yeast solution.

[0028] In some embodiments, in step S30, the mass ratio of the mixed powder to the yeast solution is 100:(50-60).

[0029] In some embodiments, in step S40, the fermentation temperature is 37 to 40 degrees Celsius, the relative humidity is 80% to 85%, and the fermentation time is 40 to 60 minutes.

[0030] In some embodiments, in step S50, the object is quick-frozen at -80 degrees Celsius for 15 to 25 minutes.

[0031] In some embodiments, in step S50, the food is frozen at -18 degrees Celsius for 7 to 14 days.

[0032] In a second aspect, the present invention provides a frozen dough containing oat β-glucan, prepared according to the method described in any embodiment of the first aspect.

[0033] The present invention also provides a method for improving the quality of frozen dough by using the above-mentioned oat β-glucan as a modifier.

[0034] In this invention, the frozen dough uses oat β-glucan as a modifier. Its loose granular structure and high water absorption properties help form a dense gluten network, reducing the damage to proteins caused by ice crystals during freezing, while improving the water retention and thermal stability of the frozen dough. Furthermore, the addition of oat β-glucan promotes cross-linking between starch and gluten proteins, stabilizes the secondary structure of proteins, inhibits the increase in thiol content during freezing, and increases disulfide bond content, thereby further enhancing the integrity of the gluten network.

[0035] In some embodiments, after being frozen and stored at -18 degrees Celsius for 7 to 14 days, the frozen dough gradually increases in hardness, and its elasticity, stickiness, adhesiveness and chewiness are significantly improved. Moreover, the freezeable water content is reduced by 20% to 30% compared with the control group without added oat β-glucan.

[0036] In some embodiments, the frozen dough, after thawing and fermentation for 50 to 60 minutes, increases in volume by 10% to 15% compared to the control group without added oat β-glucan, indicating a significant improvement in its gas-holding capacity and fermentation performance.

[0037] Thirdly, the present invention provides a method for preparing steamed buns using the above-mentioned frozen dough containing homemade oat β-glucan, comprising the following steps:

[0038] T10: Take out the frozen dough and thaw it at room temperature until the core temperature reaches 5 to 10 degrees Celsius.

[0039] T20: Place the thawed dough in a fermentation box at a temperature of 37 to 40 degrees Celsius and a relative humidity of 80% to 85% for 40 to 50 minutes, so that its volume increases to 1.5 to 2 times its original volume;

[0040] T30: Place the fermented dough in a steamer and steam for 15 to 20 minutes to obtain the finished steamed buns.

[0041] In this invention, the steamed buns prepared by the above method exhibit excellent characteristics in terms of color, texture, specific volume, and sensory evaluation. Specifically, after adding homemade oat β-glucan, the specific volume of the steamed buns increased by 10% to 20% compared to the group without addition, and the internal structure became more uniform, the texture more fluffy and soft, and the starch retrogradation process was inhibited. In addition, when the amount of homemade oat β-glucan added was 3% to 5%, the steamed buns also had a special milky aroma, making them more popular with consumers.

[0042] In some embodiments, in step T30, the temperature inside the steamer is 100 to 105 degrees Celsius, and the steaming time is 15 to 20 minutes, to ensure that the inside of the steamed bun is fully cooked and that no cracks appear on the outside.

[0043] In some embodiments, step T20 further includes introducing carbon dioxide gas into the fermentation chamber at a concentration of 1% to 3% to further promote yeast activity and improve fermentation efficiency.

[0044] Fourthly, the present invention provides a steamed bun product prepared according to the method described in the third aspect.

[0045] In this invention, because the steamed bun uses frozen dough containing homemade oat β-glucan as raw material, its dietary fiber content is significantly increased. Especially when the addition amount is 5%, the dietary fiber content of the steamed bun exceeds 6%, making it a high-fiber food. In addition, the addition of homemade oat β-glucan can also improve the textural properties of the steamed bun, enhancing its viscosity, cohesiveness, adhesiveness, and chewiness. Furthermore, it exhibits stronger free radical scavenging ability in in vitro digestion experiments.

[0046] In some embodiments, after the steamed buns are stored for 7 to 14 days, the intensity of the 17.2 degree diffraction peak in its X-ray diffraction pattern almost disappears, indicating that its starch recrystallization is significantly inhibited and the aging process is delayed.

[0047] In some embodiments, the steamed buns scored highly in sensory evaluations, especially when the addition amount was 3% to 5%, and consumer acceptance of their taste and flavor was significantly better than that of commercially available steamed buns made from oat β-glucan.

[0048] Beneficial effects

[0049] The method and technical solution provided by this invention solve the problems of insufficient antifreeze performance, limited yeast activity protection, and poor long-term frozen storage stability of frozen dough in the prior art, significantly improving the antifreeze performance, gluten network stability, and yeast activity protection ability of frozen dough. Furthermore, by adding homemade oat β-glucan, not only is the quality of the frozen dough improved, but the finished product also has higher nutritional value and better sensory qualities, demonstrating high application value and market potential. Attached Figure Description

[0050] Figure 1 The images show frozen dough steamed buns and actual steamed buns made from a mixture of wheat flour and 1%-5% homemade or commercially available oat β-glucan (A shows the whole dough and its cross-section, and B shows the whole dough and its cross-section of the steamed bun).

[0051] Figure 2 This is a scanning electron microscope image of a mixture of wheat flour and homemade oat β-glucan or commercially available oat β-glucan (scale bar = 200 μm and 100 μm) of the present invention (C-OBG is commercially available OβG, L-OBG is homemade OβG);

[0052] Figure 3 This is a particle size distribution diagram of the mixed powder of wheat flour and 1%-5% of homemade or commercially available oat β-glucan (C-OBG is commercially available OβG, L-OBG is homemade OβG);

[0053] Figure 4 The image shows the FTIR spectrum of frozen dough made from a mixture of wheat flour and 1%-5% homemade or commercially available oat β-glucan (C-OBG is commercially available OβG, L-OBG is homemade OβG).

[0054] Figure 5 The microstructure of frozen dough made from a mixture of wheat flour and homemade oat β-glucan or commercially available oat β-glucan is shown in the figure (laser confocal microscope, scale bar = 50 μm; scanning electron microscope, scale bar = 50 μm; C-OBG is commercially available OβG; L-OBG is homemade OβG).

[0055] Figure 6 This is an X-ray diffraction spectrum of frozen dough steamed buns made from a mixture of wheat flour and 1%-5% homemade or commercially available oat β-glucan (C-OBG is commercially available OβG, L-OBG is homemade OβG). Detailed Implementation

[0056] The embodiments or implementations described in this specification adopt a progressive approach, with each embodiment focusing on its differences from other embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an implementation or example that are included in at least one implementation or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more implementations or examples.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] The specific embodiments of this application are described in detail below with reference to the accompanying drawings. Unless otherwise specified, all operations in this application are performed under conventional experimental conditions, and all reagents and instruments used are commercially available products. Oat β-glucan is abbreviated as OβG. The oat β-glucan and OβG referred to below are the same substance.

[0059] Example 1: A method for preparing frozen dough containing homemade oat β-glucan

[0060] First, the method for preparing homemade oat β-glucan:

[0061] Step M1: Oat Pretreatment

[0062] Oat powder was pulverized to a particle size of 150 micrometers. Anhydrous ethanol solution with a mass of 10 times that of the oat powder was added. The mixture was stirred at 85 degrees Celsius for 3 hours, filtered to obtain a precipitate, and dried into powder for later use.

[0063] Step M2: Hot water extraction

[0064] Add 10 times the mass of deionized water to the powder, heat to 52 degrees Celsius and control the stirring speed at 200 rpm, and extract for 2 hours.

[0065] Step M3: Purification and Impurity Removal

[0066] Add 1.5% α-amylase (by weight of powder) to the extract, heat at 65°C for 2 hours to remove starch from the sample, then add 0.5% papain (by weight of powder), heat at 65°C for 3 hours to remove protein from the sample, inactivate the enzyme at 100°C, centrifuge at 8000 rpm for 20 minutes to remove the precipitate, and concentrate by rotary evaporation.

[0067] Step M4: Freeze-drying

[0068] The above concentrated solution was added to a 95% ethanol aqueous solution to precipitate the precipitate. The amount added was 4 times the volume of the extract. After 12 hours, the precipitate was centrifuged at 7000 rpm for 20 minutes. The precipitate was redissolved in water and dialyzed with running water for 24 hours. The fraction with a molecular weight greater than 8000 Daltons was retained. Subsequently, the precipitate was freeze-dried at -60 degrees Celsius for 72 hours to obtain the self-made oat β-glucan.

[0069] The basic components of homemade OβG and commercially available OβG are shown below: (Both types of OβG are dietary fiber)

[0070]

[0071] This invention provides a method for preparing frozen dough containing homemade oat β-glucan, comprising the following steps:

[0072] Step S10: Preparation of mixed powder

[0073] Medium-gluten wheat flour and the aforementioned homemade oat β-glucan were mixed evenly at a mass ratio of 95 to 99 to 1 to 5 to obtain a mixed powder. The homemade oat β-glucan was prepared in the laboratory, with a weight-average molecular weight of 110,000 Daltons and a loose granular structure.

[0074] In some embodiments, the amount of homemade oat β-glucan added is 1%-5%. Adding more than 5% severely degrades the yield of fermented products. Therefore, the OβG addition replaces wheat flour in proportions of 1%, 3%, and 5%, preferably 5%. Under these conditions, the hardness, elasticity, and gas-holding capacity of frozen dough can be significantly improved, while maintaining yeast activity unaffected.

[0075] Depend on Figure 1As shown, wheat flour particles exhibit a distinct bimodal structure, with type A being larger and type B smaller. Type A starch particles are mostly spherical or elliptical, with larger particles becoming flatter and rounder. Type B starch displays a more diverse morphology, potentially including the damaged portion of type A starch, and exhibits higher levels of edge damage and incompleteness compared to type A starch. The fillers on the surface of starch particles or between starch particles are typically composed of irregularly shaped proteins and hemicellulose. The microstructure of the oat β-glucan prepared in this application differs significantly from that of wheat flour. The oat β-glucan prepared in this invention has a relatively uniform particle size, typically ranging from a few micrometers to several hundred micrometers.

[0076] like Figure 2 As shown in the electron microscope images of the mixture of wheat flour and oat β-glucan, the presence of both wheat flour and oat β-glucan can be clearly observed. Compared with before mixing, the morphology of wheat flour did not change significantly, while the particle size of oat β-glucan decreased significantly after mixing, indicating that oat β-glucan particles have high rigidity and are easily broken during mixing. With the increase of oat β-glucan addition, the surface roughness of the mixed flour increases, and the differences between particle shapes become more significant.

[0077] The particle size distributions of wheat flour, oat β-glucan, and their mixtures are shown in the table below. The D90, D50, and D10 values ​​of OβG were significantly higher than those of wheat flour, while the dispersion of homemade OβG was significantly lower than that of wheat flour, indicating that the particle size distribution of homemade OβG was more concentrated. Commercially available OβG, on the other hand, had a higher dispersion than wheat flour because its main component is starch, making its composition more complex than that of wheat flour, resulting in a more dispersed particle size distribution. With increasing OβG addition, the D10 and D50 of the mixtures initially decreased and then increased, while the dispersion also increased. However, homemade OβG had no significant effect on the average particle size and particle size distribution of wheat flour. The amount of OβG added should be relatively small, preferably a maximum of 5%.

[0078] Table 1 Particle size distribution of the mixed powder

[0079]

[0080] Note: The letters "ae" in the same row indicate that there are statistically significant differences between different powder mixtures (p < 0.05).

[0081] like Figure 3As shown, the addition of oat β-glucan increased the peak height of the flour particle size distribution. The minimum particle size of flour and its mixtures was 2.75 μm, but the maximum particle size of flour, the mixed powder with 1% oat β-glucan, and the mixed powder with 3% oat β-glucan was 248.9 μm, and that of the mixed powder with 5% oat β-glucan was 296 μm. The maximum particle sizes of commercially available oat β-glucan and homemade oat β-glucan were 352 μm and 418.6 μm, respectively. The experimental results showed that some larger oat β-glucan particles broke during the mixing process, and the smaller the amount of oat β-glucan added, the greater the degree of particle breakage. This is consistent with the results of scanning electron microscopy, that is, wheat flour is relatively stable during mechanical mixing, while oat β-glucan particles are easily broken.

[0082] Step S20: Preparation of yeast solution

[0083] Disperse the dry yeast in warm water at 37 degrees Celsius and stir until completely dissolved to obtain a yeast solution.

[0084] In some embodiments, the dry yeast has a mass fraction of 1%, and the volume of warm water is 5 times the mass of the dry yeast. The stirring time is 5 minutes to ensure that the yeast is completely dissolved and has good activity.

[0085] Step S30: Initial dough preparation

[0086] The above-mentioned mixed powder (the mass ratio of medium-gluten wheat flour to homemade oat β-glucan is 95:5) is mixed with 1 wt% yeast solution at a mass ratio of 100:55, and kneaded by hand until the dough surface is smooth to obtain the initial dough.

[0087] In some implementations, the kneading time is 10 minutes, and the dough surface must be kept smooth and free of obvious cracks during the kneading process.

[0088] Step S40: Fermentation treatment

[0089] Place the initial dough in a fermentation box at a temperature of 37 degrees Celsius and a relative humidity of 85% for 50 minutes to ferment, so that the dough can form a complete air-porous structure inside.

[0090] In some implementations, the fermentation time is 50 minutes, and carbon dioxide gas at a concentration of 2% is introduced into the fermentation chamber to further promote yeast activity and improve fermentation efficiency.

[0091] Step S50: Quick-freezing and frozen storage

[0092] After fermentation, the dough is kneaded by hand to remove internal air pockets, sealed with plastic wrap, and flash-frozen at -80 degrees Celsius for 20 minutes; then transferred to -18 degrees Celsius for freezing storage for 10 days to obtain freeze-resistant dough.

[0093] The resulting frozen dough exhibited significantly improved hardness, elasticity, stickiness, adhesiveness, and chewiness, and its freezeable water content was reduced by 20% to 30% compared to the control group without added oat β-glucan.

[0094] By replacing the homemade oat β-glucan in step S10 with an equal amount of commercially available oat β-glucan, and following the same process as in Example 1, a corresponding frozen dough control was obtained.

[0095] Effect of oat β-glucan on the texture properties of frozen dough

[0096] The texture characteristics of the frozen dough and control obtained from homemade oat β-glucan in Example 1 were tested, and the results are shown in Table 2.

[0097] Test method: Measurements were performed using a texture profile analyzer in TPA (Transformer Profile Analysis) mode. The initial velocity was 2.00 mm / s, the test velocity was 2.00 mm / s, and the post-test velocity was 1.00 mm / s. The puncture distance was 1.0 mm, the interval was 5 seconds, and a TA10 cylindrical probe was used. Five parameters were measured: hardness, elasticity, cohesiveness, adhesiveness, and chewiness.

[0098] Table 2 Texture characteristics of frozen dough

[0099]

[0100] Note: The letters af in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0101] Table 2 shows that the hardness of the frozen dough gradually increased with increasing OβG addition. This is because the content of denatured proteins in the dough gradually increased, leading to more exposed hydrophobic groups, which in turn made the gluten protein network structure more compact, further increasing the dough hardness. Except for the frozen dough with 1% OβG, all other addition amounts showed an increasing trend in elasticity, viscosity, adhesiveness, chewiness, and stringiness. These results are due to the fact that OβG can interact with free water in the dough, reducing the amount of freezeable water, thereby reducing ice crystal formation and further reducing the damage to the dough texture. The increase in frozen dough hardness indicates that OβG treatment can, to some extent, reduce the adverse effects of the freezing process, enhance food stability, and improve the impact of ice crystals on the gluten network structure of frozen dough.

[0102] Effect of oat beta-glucan on gluten content of frozen dough

[0103] One of the commonly used indicators for measuring the quality of flour protein and baking quality is the content of wet gluten.

[0104] The specific testing method includes: Weighing 10 grams of sample and placing it in a beaker, recorded as m1. Adding 5.0 mL of NaCl solution dropwise while continuously stirring to form dough balls. Washing the dough balls with NaCl solution at a flow rate of 50 mL / min for 8 minutes, followed by rinsing with tap water and kneading until the starch is completely removed. Squeezing out the free water from the gluten using a pressure plate. After draining, weighing the gluten balls, recorded as m2. Determining the wet gluten content using a formula. Weighing the clean pan and recording the mass as m0, and recording the initial mass of the wheat flour sample as m. The wet gluten balls prepared by the above method are placed on a pan, and the total mass of the pan and wet gluten is then weighed and recorded as m4. Drying the pan in an oven at 130 degrees Celsius for 2 hours, then making 3 to 4 parallel cuts on the semi-dried gluten, followed by an additional 4 hours of drying on the pan. Next, cooling the pan and dried gluten to room temperature in a desiccator. The total mass of the pan and dried gluten is weighed and recorded as m3. Dry gluten content of the sample (G) dry ) and the moisture content (W) of wet gluten G The results are calculated according to the formulas respectively.

[0105] wet gluten content: G wet = (m2 / m1) × 100%;

[0106] Dry gluten content: G dry = [(m3-m0) / m]×100%;

[0107] Moisture content of wet gluten: W G =[(m4-m3) / (m4-m0)]×100%.

[0108] The specific results are shown in Table 3.

[0109] Table 3 Gluten content of frozen dough

[0110]

[0111] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0112] Table 3 shows that the dry gluten content, wet gluten content, and wet gluten moisture content of frozen dough with only 1% commercially available OβG were higher than those of frozen dough made from wheat flour. However, the dry gluten content, wet gluten content, and wet gluten moisture content of frozen dough with 3% and 5% commercially available OβG all showed a decreasing trend, with the gluten moisture content of the dough with 5% commercially available OβG (67.82%) being significantly lower than that of the frozen dough made from wheat flour (70.99%). This may be because low concentrations of commercially available OβG promote gluten formation, while high concentrations may compete with gluten proteins for water absorption, thus inhibiting gluten network formation. On the other hand, the dry gluten content, wet gluten content, and wet gluten moisture content of frozen dough with homemade OβG all showed an increasing trend, with the gluten moisture content of the dough with 5% commercially available OβG (78.64%) being significantly higher than that of the frozen dough made from wheat flour (70.99%). This indicates that adding homemade OβG promotes gluten network formation and can significantly enhance the water absorption capacity of gluten proteins.

[0113] The effect of oat β-glucan on thiol groups and disulfide bonds in frozen dough

[0114] During frozen storage, the -SH content increased while the -SS- content decreased due to continuous depolymerization by GMP. The effects of oat β-glucan on the thiol and disulfide bonds in frozen dough are shown in Table 4. After adding OβG, free -SH significantly decreased while -SS- significantly increased. This effect became more pronounced with increasing amounts of homemade OβG, effectively reducing free -SH content and increasing -SS- content. The increase in free -SH may weaken gluten stability, while the presence of -SS- bonds may make the spatial structure of protein peptide chains more compact; the addition of dietary fiber altering the tertiary structure of proteins may also cause changes in the disulfide bond content of gluten proteins. Therefore, the increase in free -SH content and the decrease in -SS- content make gluten protein molecules less prone to cross-linking and aggregation, weakening the interaction between gluten molecules and reducing extensibility, thus leading to a decrease in gluten strength. This is consistent with the gluten content measurement results, indicating that adding OβG can effectively stabilize the formation of the gluten network and help maintain the integrity of gluten proteins.

[0115] Table 4. Thiol and disulfide bond content of frozen dough

[0116]

[0117] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0118] The effect of oat β-glucan on the secondary structure of frozen dough

[0119] Table 5 shows that the percentage of α-helical structures increases with increasing OβG addition, indicating that OβG significantly increases the elasticity and firmness of the dough. Generally, β-sheets are considered the most stable secondary structure in gluten, while random coils are the most disordered secondary structure in proteins. With increasing OβG addition, the percentage of β-turn structures in the dough increased in both types of OβG, while the percentage of random coils decreased in commercially available OβG. However, with increasing homemade OβG addition, the percentage of random coils in the dough decreased. The percentage of β-sheet structures in frozen dough with 1% and 3% homemade OβG increased, while the percentage of β-sheet structures in frozen dough with 5% homemade OβG decreased. These results suggest that OβG may stabilize the secondary structure of proteins by reducing the damage to gluten structure during freezing. In a mixed flour system, the redistribution of water promotes partial dehydration of gluten, and the β-turn (in the form of a β-helix) transforms into an intermolecular β-sheet structure. This trans conformation is the physical reason for the poor quality of commercially available OβG.

[0120] Table 5. Secondary structure of gluten proteins in frozen dough.

[0121]

[0122] Figure 4 The Fourier transform infrared spectrum of frozen dough was observed. Figure 4 It can be seen that no new peaks appeared or disappeared in the spectra of any of the samples, indicating that the addition of OβG did not cause the 3600-3000 cm⁻¹ peak to appear. -1 and 2950-2850cm -1 The peak increases at [location missing]. The broadening of the spectral band indicates enhanced hydrogen and CH bonds. [Percentage missing] in the 1300-800 cm⁻¹ range. -1 The peak intensity of the starch region gradually increased with the extension of storage time, indicating that the starch in the dough did indeed degrade and form hydrogen bonds during frozen storage.

[0123] The effect of oat beta-glucan on the freezeable water content of frozen dough

[0124] The formation, expansion, and recrystallization of ice crystals in dough after freezing can damage the gluten protein structure, leading to collapse and shrinkage of the dough products. The amount of ice crystals in dough can be reflected in the freezerable water content. An increase in freezerable water content may be due to the exposure of hydrophobic groups in proteins during freezing, thereby reducing the binding force between proteins and water. This, in turn, causes water molecules to be released from the gluten proteins, thus increasing the amount of freeze-thawed water. As shown in Table 6, the freezerable water content in frozen dough with added OβG is significantly reduced. This is because OβG has strong water absorption properties, which can improve the water absorption and retention capacity of the dough system, and homemade OβG has a better water retention capacity than commercially available OβG. Although adding OβG cannot completely prevent the increase in freezerable water content, it can significantly reduce its increasing trend. This indicates that OβG can enhance the binding between the frozen dough system and water, thereby improving the water retention and storage stability of the dough.

[0125] Table 6. Freezeable water content of frozen dough

[0126]

[0127] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0128] The effect of oat β-glucan on the microstructure of frozen dough

[0129] like Figure 5 As shown, after one week of frozen storage, in the untreated control group, starch particles detached from the gluten network structure, making the network structure coarser. With increasing amounts of commercially available OβG, dough porosity increased. OβG's high water-holding capacity led to the formation of large ice crystals after freezing. These large ice crystals were detrimental to maintaining the network structure, causing protein macroaggregates to depolymerize and creating numerous pores. Conversely, frozen dough with homemade OβG exhibited a more intact and denser gluten structure, appearing more visually fuller. Furthermore, the effect improved with increasing amounts of OβG, indicating that homemade OβG inhibited ice crystal distribution and crystal size, demonstrating better frozen storage stability. This may be because it strengthened the rigid structure of gluten proteins in the frozen dough, causing free water to crystallize into small ice crystals with minimal structural damage, thus maintaining the integrity of the dough's structure.

[0130] Effects of oat β-glucan on the fermentation properties of frozen dough

[0131] Referring to Table 7 below, yeast activity is a crucial indicator of frozen storage quality. However, due to its poor cold resistance, yeast activity during frozen storage is significantly correlated with fermentation time, bread volume, hardness, and porosity. As yeast activity decreases, gas production during fermentation decreases, and fermentation time also increases. During frozen storage, yeast is subjected to various stresses such as freeze-thaw cycles, high osmotic pressure, and oxidative stress, leading to decreased activity and even death. Therefore, appropriate temperature control is essential during frozen storage. The CO2 produced in the dough is only related to yeast activity; therefore, the amount of CO2 produced can be used to determine the yeast activity level. Each dough volume before fermentation was 14 mL. During fermentation, the decrease in pH is due to CO2 dissolving in water to form carbonic acid, and the production of organic acids by bacteria in the dough, including acetic acid, ethanol, glycerol, succinic acid, and other secondary metabolites, resulting in a decrease in dough pH and an increase in titratable acid. Furthermore, this may also be related to the metabolic state of yeast under different production methods; yeast growth under low-temperature stress may alter carbon flux, leading to the production of more organic acids and other substances. Data before freezing showed that the addition of OβG had no significant effect on pH and titratable acidity during fermentation, indicating that adding OβG during fermentation had no significant impact on yeast activity. Compared to wheat flour dough before freezing, the volume of dough with commercially available OβG was significantly smaller, while the volume of dough with homemade OβG was larger. This is because adding commercially available OβG increases dough solids, which inhibits dough expansion during fermentation and significantly reduces the dough's gas-holding capacity. However, as mentioned above, adding homemade OβG helps form a gluten network and enhances the water absorption capacity of gluten proteins, which is beneficial for dough fermentation and expansion, significantly improving the dough's gas-holding capacity. Compared to the data before freezing, the increased pH, decreased titratable acidity, and reduced dough volume after freezing indicate that the quality deteriorated during freezing due to the destruction of the gluten network structure and the reduction in yeast fermentation activity. The volume of dough with commercially available OβG after freezing was significantly smaller than that of wheat flour dough, while the volume of dough with homemade OβG was significantly larger than that of wheat flour dough. This indicates that commercially available OβG did not improve the deterioration of frozen dough properties. On the contrary, due to its strong water absorption, it inhibited the formation of dough networks, and even the yeast fermentation ability was inferior to the blank control group. The dough with added homemade OβG showed a slower rate of volume decrease, indicating that it can delay the trend of dough quality deterioration and is beneficial to storage stability.

[0132] Table 7 Effects of freezing on dough pH, ​​total acidity, and volume.

[0133]

[0134] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0135] Compared to pre-freezing data, freezing resulted in increased pH, decreased titratable acidity, and reduced dough volume, indicating a decline in dough quality due to freezing and storage processes. With increasing OβG addition, the hardness of the frozen dough gradually increased; free -SH significantly decreased while -SS- significantly increased; the percentage of α-helical structures increased, the percentage of β-turn structures increased, and the percentage of random coil structures decreased; the freezeable water content in the dough significantly decreased; and yeast activity was not affected. After freezing, the dough volume with commercially available OβG was significantly smaller than that with wheat flour dough, while the dough volume with homemade OβG was significantly larger than that with wheat flour dough. Except for the frozen dough with 1% OβG, all other addition amounts showed an increasing trend in elasticity, viscosity, adhesiveness, chewiness, and stringiness. The frozen dough with homemade OβG showed an increasing trend in dry gluten content, wet gluten content, and moisture content. Scanning electron microscopy images showed that the dough with homemade OβG had a complete and dense gluten network and plump starch granules, indicating that homemade OβG effectively inhibited ice crystal distribution and crystal size, exhibiting better frozen storage stability.

[0136] Example 2: Method for preparing steamed buns using frozen dough containing homemade oat β-glucan

[0137] This invention provides a method for preparing steamed buns using frozen dough containing homemade oat β-glucan, comprising the following steps:

[0138] Step T10: Thawing process

[0139] The frozen dough obtained in Example 1 was taken out from -18 degrees Celsius and thawed at room temperature (25 degrees Celsius) for 3 hours until the center temperature reached 10 degrees Celsius.

[0140] Step T20: Secondary fermentation

[0141] Place the thawed dough in a fermentation box at 37 degrees Celsius and 85% relative humidity, introduce 2% carbon dioxide gas, and ferment for 45 minutes until its volume doubles.

[0142] Step T30: Steaming process

[0143] Place the fermented dough in a steamer and steam at 105 degrees Celsius for 18 minutes to obtain the finished steamed buns.

[0144] Using the frozen dough control product prepared from the commercially available oat β-glucan mentioned above, the corresponding steamed bun control product was obtained by following the process in Example 2.

[0145] The effect of oat beta-glucan on the color of frozen dough steamed buns

[0146] Table 8: Color of Steamed Buns

[0147]

[0148] Note: The letters "ad" in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0149] During frozen storage, polyphenol oxidase undergoes enzymatic browning in the dough, and the amino carbonyl groups undergo Maillard reactions, both of which cause the bread slices to deteriorate in color. Additionally, moisture loss from the flour reduces the dough's gloss. During freezing, protein denaturation in the flour leads to structural deterioration, also affecting the overall color of the dough. With increasing β-glucan addition, the whiteness of the steamed buns decreases. The Maillard reaction has a relatively minor impact on the color of the steamed buns; the darkening of the steamed buns after adding OβG is mainly due to the fact that OβG itself is darker than wheat flour. Adding homemade OβG has little effect on color because homemade OβG has a better protective effect on the gluten network structure, better hydrophilicity, and better water retention, effectively absorbing moisture into the dough and reducing the chance of dehydration. These factors contribute to improving the overall color of frozen dough steamed buns.

[0150] The effect of oat β-glucan on the quality of frozen dough steamed buns

[0151] Table 9: Quality of Steamed Buns

[0152]

[0153] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0154] Specific volume is a comprehensive reflection of the changes in the properties of frozen dough systems and can directly reflect the quality characteristics of steamed buns. Generally, the optimal specific volume range for steamed bun quality is 2.3-2.6 mL / g. The formation and expansion of the gluten network structure in steamed buns are important factors affecting their quality and height. As shown in Table 9, with the increase of commercially available OβG, the specific volume of steamed buns decreased significantly, seriously affecting their quality. This is because with the increase of commercially available OβG, the formation of the gluten network is severely hindered, resulting in a smaller diameter of the steamed bun and a larger height-to-diameter ratio. The textural results indicate that adding commercially available OβG makes the dough more elastic and chewy, easily forming a crumbly dough, which hinders the fermentation process, leading to a smaller volume and greater internal stickiness in the steamed bun. Conversely, the addition of homemade OβG increased the specific volume and decreased the height-to-diameter ratio; this is because the dough has a higher wet gluten content, promoting the formation and expansion of the gluten network structure in the steamed bun. In this case, the volume of the steamed bun relatively increases, increasing the specific volume and decreasing the height-to-diameter ratio. This indicates that homemade OβG can strengthen the dough network structure, improve dough extensibility and gas retention, promote dough expansion and shaping during fermentation, and mitigate the deterioration of steamed bun quality caused by freezing. Frozen foods often experience water loss during storage. During frozen storage, water and ice in the frozen dough gradually transform into frost. Water loss is mainly caused by the water vapor pressure difference between the steamed bun and the air. Furthermore, ice crystals during freezing can damage the gluten network, leading to the dissociation of hydrogen and ionic bonds in the gluten. Mechanical damage also causes the release of water bound to starch, and the decreased water-holding capacity of gluten and starch also leads to water migration and loss. As shown in Table 10, the moisture content of steamed buns with both types of OβG-added products was significantly higher than that of the blank control group. Moreover, steamed buns with homemade OβG showed less deterioration and stronger protective effect during frozen storage. The increased moisture content indicates that the high water-holding capacity of OβG during steaming makes the steamed buns less prone to moisture loss and slows down aging.

[0155] The effect of oat β-glucan on the crystal structure of frozen dough steamed buns

[0156] according to Figure 6 The results showed that the control group of steamed buns exhibited a V-type diffraction peak at 20.2° and a B-type starch diffraction peak at 17.2°. This indicates that starch retrogradation may have occurred in the steamed buns made from frozen dough. Starch retrogradation leads to a reduction in the soluble starch content of the steamed buns, and also deteriorates their texture and taste. Furthermore, with the addition of OβG, the B-type starch diffraction peak decreased, especially in the steamed buns with 5% homemade OβG, where the intensity of the 17.2° diffraction peak almost disappeared. This suggests that the addition of OβG inhibited starch recrystallization in the steamed buns to some extent, thus delaying the retrogradation process.

[0157] Effects of oat β-glucan on the texture of frozen dough steamed buns

[0158] As shown in Table 10, the hardness of steamed buns significantly increased with increasing amounts of commercially available OβG. Besides hardness, adding 1% commercially available OβG had no significant effect on the texture properties of steamed buns; however, adding 3% or 5% commercially available OβG significantly increased the hardness, stickiness, cohesiveness, adhesiveness, and chewiness of the steamed buns. In general, adding 3% or 5% commercially available OβG deteriorated the texture of the steamed buns because excessive dietary fiber interfered with the formation of the gluten protein network structure. Dietary fiber has a strong water-absorbing capacity, drawing moisture from the gluten protein. On the other hand, adding homemade OβG increased the stickiness, cohesiveness, adhesiveness, and chewiness of the steamed buns. Besides the fact that adding 5% homemade OβG reduced the hardness of the steamed buns, according to published literature by Scanlon et al., the initial hardness of breadcrumbs depends on the crystallization of amylose. Therefore, adding 5% homemade OβG inhibited the recrystallization of starch in the steamed buns, suggesting that adding 5% homemade OβG can reduce the hardness of the steamed buns, making them softer.

[0159] Table 10 Texture of Steamed Buns

[0160]

[0161] Note: The letters "ad" in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0162] The effect of oat β-glucan on the sensory evaluation of frozen dough steamed buns

[0163] Table 12 shows that OβG had no significant effect on the appearance, elasticity, stickiness, or crust structure of steamed buns during frozen storage. However, the addition of 3% and 5% commercially available OβG resulted in a decrease in the specific volume of the steamed buns, a darker color, and an increase in the pore area, a decrease in the number of pores, and uneven pore size in the core. The darker color and slightly sour taste of commercially available OβG led to the deterioration of the color and flavor of the steamed buns. The deterioration of the specific volume and core pore structure was due to the dilution of protein in the dough by the fortified oat β-glucan, which interfered with the formation of the gluten network structure, resulting in an overly dense core and poor texture. Conversely, the steamed buns with homemade OβG showed significantly better overall sensory indicators than the other two groups. Through rheological, microstructural, specific volume, and texture tests, this study reveals that the quick-frozen dough with homemade OβG can effectively inhibit gluten network collapse, decreased yeast activity, moisture loss, and browning, thereby improving the quality deterioration of frozen steamed buns. Adding homemade OβG will give the steamed buns a special milky flavor, making them more appealing to consumers.

[0164] The sensory evaluation scoring rules are shown in Table 11:

[0165] Table 11 Sensory Evaluation Criteria for Steamed Buns

[0166]

[0167] Table 12 Sensory Evaluation Scoring Table for Steamed Buns

[0168]

[0169] Note: The letters ag in the same row indicate that there is a statistically significant difference between different frozen doughs (p < 0.05).

[0170] In summary, this study investigated the effects of OβG on the color, quality, texture, crystal structure, and sensory quality of frozen dough steamed buns. Overall, increasing OβG dosage reduced the whiteness of the steamed buns, significantly increased the moisture content, and almost eliminated the 17.2° diffraction peak intensity in the X-ray diffraction pattern, indicating inhibition of starch recrystallization. Adding 3% or 5% commercially available OβG deteriorated the texture of the steamed buns, resulting in a larger aspect ratio, lower specific volume, and a stickier core. The addition of homemade OβG increased the specific volume of the steamed buns, decreased their aspect ratio, and improved their stickiness, cohesiveness, adhesiveness, and chewiness. Furthermore, the scavenging effect on free radicals in the digestive fluids at each stage increased with increasing dosage.

[0171] The specific embodiments of this invention establish a gradient of 1%, 3%, and 5% oat β-glucan addition, and demonstrate in detail the effects of oat β-glucan on flour powder properties, frozen dough processing characteristics, and steamed bun quality. This invention has significant advantages over existing technologies:

[0172] (1) Compared with wheat flour, oat β-glucan has a darker color, better dispersibility, greater rigidity, and is more easily broken during mixing. It can improve the flowability and crystallinity of wheat flour. A small amount added has no significant effect on the particle size distribution of wheat flour. Adding oat β-glucan significantly increases the crystallinity and water absorption of wheat flour, and also increases its solubility and swelling. Commercially available oat β-glucan has no effect on the compressibility of wheat flour, but its addition leads to a decrease in the freeze-thaw stability of wheat flour; while homemade oat β-glucan is more loosely distributed, which can improve the compressibility and freeze-thaw stability of wheat flour.

[0173] (2) With increasing amounts of oat β-glucan, the hardness of the frozen dough gradually increased; free -SH significantly decreased, while -SS- significantly increased; the percentage of α-helical structures increased, the percentage of β-turn structures increased, and the percentage of random coil structures decreased; the freezeable water content in the dough significantly decreased; and yeast activity was not affected. The volume of dough with commercially available oat β-glucan added after freezing was significantly smaller than that of wheat flour dough, while the volume of dough with homemade oat β-glucan added was significantly larger than that of wheat flour dough. Except for the frozen dough with 1% oat β-glucan added, all other addition amounts showed an increasing trend in elasticity, viscosity, adhesiveness, chewiness, and string length. The dry gluten content, wet gluten content, and moisture content of the frozen dough with homemade oat β-glucan added all showed an increasing trend. Scanning electron microscopy showed that the dough with homemade oat β-glucan added had a complete and dense gluten structure, full starch granules, effectively inhibited ice crystal distribution and crystal size, and exhibited better frozen storage stability.

[0174] (3) After adding commercially available oat β-glucan, the steamed buns darkened in color, deteriorated in texture, decreased in specific volume, and became less uniform in internal structure. When the addition amount was 1%–3%, it had little impact on the sensory evaluation of the steamed buns; however, when the addition amount exceeded 5%, the sensory score decreased significantly. At this point, the dietary fiber content of the steamed buns exceeded 6%, making them a high-fiber food. Adding homemade oat β-glucan darkened the color of the steamed buns and increased their specific volume, inhibiting starch recrystallization and delaying the aging process. Simultaneously, the addition of homemade oat β-glucan made the steamed buns fluffier and softer, and when the addition amount was 3%–5%, it imparted a special milky aroma, making it more appealing to consumers.

[0175] In summary, the properties of homemade oat β-glucan are superior to those of commercially available oat β-glucan. The appropriate amount of homemade oat β-glucan is approximately 5%. The method and technical solution provided in this application address the problems in existing technologies regarding insufficient freeze resistance of frozen dough, limited yeast activity protection, and poor long-term frozen storage stability. Furthermore, by adding homemade oat β-glucan, not only is the quality of frozen dough improved, but the finished product also possesses higher nutritional value and better sensory characteristics, demonstrating significant advantages and a broad market prospect.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing frozen dough containing oat β-glucan, characterized in that, Includes the following steps: S10: Mix medium-gluten wheat flour with homemade oat β-glucan evenly to obtain a mixed powder; S20: Dissolve dry yeast in water to obtain a yeast solution; S30: Mix the above-mentioned powder with the yeast solution and knead by hand until the dough surface is smooth to obtain the initial dough; S40: Ferment the initial dough for a period of time to allow the dough to form a complete porous structure. S50: The fermented dough is kneaded by hand to remove internal air pockets, then sealed with plastic wrap and quick-frozen. The dough was then frozen and stored to obtain frozen dough; The method for preparing the homemade oat β-glucan includes the following steps: Oat bran was pulverized into powder with a particle size of 100 to 200 micrometers and added to distilled water to prepare a suspension with a mass fraction of 10% to 15%. An alkaline substance was added to the suspension to adjust the pH value to 9 to 10, and the mixture was heated and stirred to obtain an extract. The extract was cooled to room temperature and centrifuged. The supernatant was collected and ethanol was added to precipitate the extract to obtain a crude extract. The crude extract was dissolved in water and filtered through an ultrafiltration membrane to retain the fraction with a molecular weight range of 150,000 to 300,000 Daltons. The fraction was then freeze-dried to obtain the self-made oat β-glucan.

2. The method according to claim 1, characterized in that, In step S10, the mass ratio of medium-gluten wheat flour to homemade oat β-glucan is (95-99):(1-5).

3. The method according to claim 1, characterized in that, In step S10, the homemade oat β-glucan has a molecular weight range of 150,000 to 300,000 Daltons and has a loose granular structure.

4. The method according to claim 1, characterized in that, In step S10, the homemade oat β-glucan has the following composition: moisture content 7.81% ± 0.05%, ash content 10.94% ± 0.15%, total sugar content 71.94% ± 1.18%, total phenol content 1.06% ± 0.02%, protein content 4.91% ± 0.07%, uronic acid content 2.64% ± 0.04%, reducing sugar content 7.45% ± 0.23%, and β-glucan content 63.14% ± 0.16%.

5. The method according to claim 1, characterized in that, In step S30, the mass ratio of the mixed powder to the yeast solution is 100:(50-60).

6. The method according to claim 1, characterized in that, In step S40, the fermentation temperature is 37°C to 40°C, the relative humidity is 80% to 85%, and the fermentation time is 40 minutes to 60 minutes.

7. The method according to claim 1, characterized in that, In step S50, the sample is quick-frozen at -80 degrees Celsius for 15 to 25 minutes; then frozen at -18 degrees Celsius for 7 to 14 days.

8. A frozen dough containing oat β-glucan prepared by the method according to any one of claims 1-7.

9. A method for making steamed buns, characterized in that, Includes the following steps: T10: Take out the frozen dough as described in claim 8 and thaw it at room temperature until the core temperature reaches 5 to 10 degrees Celsius; T20: Place the thawed dough in a fermentation box at a temperature of 37 to 40 degrees Celsius and a relative humidity of 80% to 85% for 40 to 50 minutes, so that its volume increases to 1.5 to 2 times its original volume; T30: Place the fermented dough in a steamer and steam for 15 to 20 minutes to obtain the finished steamed buns.

10. A steamed bun product prepared by the method of claim 9.

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