Bread and preparation method thereof

Abstract

The invention belongs to the field of food, and discloses bread which is prepared from the following raw materials: wheat flour, red rice flour, eggs, salt, sugar, yeast and butter. Wherein the weight ratio of the wheat flour to the red rice flour is (227.5-250): (5-10). The positive influence of the red rice flour on the related performance of the bread is proved by adopting specific volume and texture evaluation and color and sense evaluation. The second purpose of the invention is to provide a preparation method of the bread.

Description

Technical Field

[0001] The invention discloses bread and a preparation method thereof, belonging to the technical field of food. Background Art

[0002] The quality of bread is related to the following indicators:

[0003] Texture, morphological characteristics, aroma components, sensory indicators, etc.

[0004] The patent application with publication number CN108184957A and the subject matter of Saffron Blood Nourishing Health Bread discloses the use of cooked rice to change the rheological properties and texture properties of the dough, improve the organizational state and texture of the bread, delay the aging of the bread, and extend the best taste time of the bread, but the scheme only literally describes the texture properties.

[0005] There is no in-depth study on how additional ingredients in bread affect the texture and morphological characteristics.

[0006] The patent application with publication number CN117598337A, which is about a toast bread and a preparation method thereof, uses GB / T20981-2007 "Bread" and probe P50 to comprehensively and scientifically evaluate the effects of changes in various ingredients in toast bread on texture and morphological characteristics.

[0007] We believe that in the food industry, using scientific research methods to study the effects of different food ingredients on food texture is the only way to clearly understand the mechanism of action of the food ingredient.

[0008] In the further research of this application, we analyzed the influence of different raw materials on the texture of bread and obtained certain research results, and specially filed this patent application. Summary of the invention

[0009] In view of the above-mentioned deficiencies, the first object of the present invention is to provide a bread, which proves the positive effect of red rice flour on bread-related properties by adopting specific volume and texture evaluation, color and sensory evaluation.

[0010] The second object of the present invention is to provide a method for preparing the bread.

[0011] To achieve the above object, the first technical solution provided by the present invention is as follows:

[0012] A bread, wherein the raw materials for making the bread include wheat flour, red rice flour, eggs, salt, sugar, yeast and butter;

[0013] Among them, the weight ratio of wheat flour to red rice flour is 227.5-250:5-10.

[0014] The invention has been proved through experiments that adding a proper amount of red rice flour can improve the color of the inside and outside of the bread, improve the texture, grain structure, and flexibility of the surface of the bread, and significantly improve the taste;

[0015] At the same time, it is also proved that the addition of red rice flour will weaken the fermentation kinetics process. From the above conclusions, it can be roughly known that the faster the fermentation process is, the faster the texture, texture structure, softness and taste are not positively correlated. The above product characteristics are related to multiple factors including but not limited to the fermentation process, raw material ratio, etc.

[0016] In the above bread, the raw materials for making the bread also include dark red roses, and the weight ratio of the flour to the dark red roses is 227.5-242.7:5-22.5, and more preferably 235-240:5-7.5.

[0017] In further research of the present invention, it was found that the dark red rose would weaken the volume, shape, texture, and other properties to a certain extent, and the improvement in flexibility was not obvious, but the taste was improved to a certain extent;

[0018] This shows that using a reasonable amount of Dark Red Rose can give the bread a pleasant floral aroma and improve the taste, but the texture data of the bread will be weakened, so the amount of Dark Red Rose used needs to be controlled.

[0019] From another perspective, using red rice flour is an effective way to reduce the negative impact of dark red rose when used in bread.

[0020] In the above bread, the particle size of the red rice flour is ≤75 μm.

[0021] In the above bread, the particle size of the dark red rose is ≤50 μm.

[0022] In the above bread, the weight ratio of wheat flour, milk, salt, sugar, yeast and butter is: 227.5-250: 25-35: 1.5-2.5: 20-30: 4-6: 18-22.

[0023] In the above bread, the weight ratio of wheat flour, eggs, salt, sugar, yeast and butter is: 227.5-250:30:2:15:5:20.

[0024] At the same time, the present invention also discloses a method for preparing the bread as described above, comprising the following steps:

[0025] Step 1: Put all ingredients except butter, yeast and salt into a dough mixing bowl, mix until there is no dry powder, add yeast, mix evenly, add salt, and stir until a film forms;

[0026] Step 2: Add softened butter to the dough and knead until the surface of the bowl is smooth and film-forming;

[0027] Step 3: Move the dough to a turnover box and let it rise at room temperature for 0.8 to 1.2 hours, with the volume expanding by 0.8 to 1.2 times;

[0028] Step 4: Take out the dough, pat it gently to release the air, divide it into 100g / piece of dough, roll it into balls and let it relax for a while;

[0029] Step 5: The dough is subjected to secondary fermentation in a fermentation cabinet at 34-36° C. and a relative humidity of 80-90 wt % for 0.8-1.2 h, and the volume expansion increases by 0.8-1.2 times;

[0030] Step 6: Put the dough into the oven, steam it for 4 to 6 seconds, with the upper and lower fire at 185 to 195°C, bake it for 18 to 22 minutes, and get the bread after cooling to room temperature.

[0031] In the above preparation method, the following steps are included:

[0032] Step 1: Put all ingredients except butter, yeast and salt into a dough mixing bowl, mix until there is no dry powder, add yeast, mix evenly, add salt, and stir until a film forms;

[0033] Step 2: Add softened butter to the dough and knead until the surface of the bowl is smooth and film-forming;

[0034] Step 3: Move the dough to a turnover box and let it rise at room temperature for 1 hour until its volume doubles;

[0035] Step 4: Take out the dough, pat it gently to release the air, divide it into 100g / piece of dough, roll it into balls and relax it for 15 minutes;

[0036] Step 5: The dough is subjected to secondary fermentation in a fermentation cabinet at 35° C. and a relative humidity of 85 wt % for 1 hour, and the volume expands by 1 time;

[0037] Step 6: Put the dough into the oven, steam it for 5 seconds, bake it at 190℃ for 20 minutes, and get the bread after cooling to room temperature.

[0038] In the above preparation method, the ratio of flour to water in step 1 is 227.5-250:150.

[0039] Compared with the prior art, the technical solution provided by the present invention has the following technical advantages:

[0040] The present invention has been tested through experiments, and the positive influence of red rice flour on bread-related properties has been proved by adopting specific volume and texture evaluation, color and sensory evaluation. The present invention has proved that the appropriate addition of red rice flour can improve the internal and external colors of bread, improve the surface texture, grain structure, softness and elasticity, and significantly improve the taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the electron microscope image of the blank sample;

[0042] Figure 2 is the electron microscope image of sample B2;

[0043] Figure 3 is the electron microscope image of sample B4;

[0044] Figure 4 This is the electron microscope image of sample C3B2;

[0045] Figure 5 This is the electron microscope image of sample C3B4;

[0046] Figure 6 This is the electron microscope image of sample C6B2;

[0047] Figure 7 This is the electron microscope image of sample C6B4;

[0048] Figure 8 This is the electron microscope image of sample C9B2;

[0049] Fig. 9 This is the electron microscope image of sample C9B4. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with specific implementation methods, but those skilled in the art should understand that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the technical solution of the present invention, and these modifications and replacements all fall within the scope of protection of the present invention.

[0051] Preparation of rose bread

[0052] The preparation method is as follows:

[0053] Step 1: Put the raw materials except butter, yeast and salt into the dough mixing bowl, add 150g of water, mix and stir until there is no dry powder, add yeast, mix evenly, add salt, and stir until a film forms; among them, the dark red rose flour is sieved through a 300-mesh sieve, and the red rice flour is sieved through a 200-mesh sieve;

[0054] Step 2: Add softened butter to the dough and knead until the surface of the bowl is smooth and film-forming;

[0055] Step 3: Move the dough to a turnover box and let it rise at room temperature for 1 hour until its volume doubles;

[0056] Step 4: Take out the dough, pat it gently to release the air, divide it into 100g / piece of dough, roll it into balls and relax it for 15 minutes;

[0057] Step 5: The dough is subjected to secondary fermentation in a fermentation cabinet at 35° C. and a relative humidity of 85 wt % for 1 hour, and the volume expands by 1 time;

[0058] Step 6: Put the dough into the oven, steam it for 5 seconds, bake it at 190℃ for 20 minutes, and get the bread after cooling to room temperature.

[0059] Its ingredients are shown in Table 1 below;

[0060] Table 1 Ingredients Unit: g

[0061] Ingredients (g) Control B2 B4 C3B2 C3B4 C6B2 C6B4 C9B2 C9B4 Wheat flour 250 250 245 240 235 242.5 237.5 232.5 227.5 Dark red rose 0 0 0 7.5 7.5 15 15 22.5 22.5 Red Rice Noodles 0 5 10 5 10 5 10 5 10 egg 30 30 30 30 30 30 30 30 30 water 150 150 150 150 150 150 150 150 150 Salt 2 2 2 2 2 2 2 2 2 sugar 25 25 25 25 25 25 25 25 25 yeast 5 5 5 5 5 5 5 5 5 butter 20 20 20 20 20 20 20 20 20

[0062] The electron microscope photos of the above samples are as follows Figures 1 to 9 As shown;

[0063] in, Figure 1 This is the electron microscope image of the blank sample; Figure 2 is the electron microscope image of sample B2; Figure 3 is the electron microscope image of sample B4; Figure 4 This is the electron microscope image of sample C3B2; Figure 5 This is the electron microscope image of sample C3B4; Figure 6 This is the electron microscope image of sample C6B2; Figure 7 This is the electron microscope image of sample C6B4; Figure 8 This is the electron microscope image of sample C9B2; Fig. 9 This is the electron microscope image of sample C9B4.

[0064] Test methods and test results

[0065] 1. Bread volume and texture

[0066] 1.1. Specific volume

[0067] Weigh the bread to be tested to an accuracy of 0.1 g.

[0068] When the volume of the bread to be tested is not more than 400mL, first cover the bottom box, open the top box lid and the plug plate, put the filler in from the top box to the zero line of the ruler, cover the top cover, turn it upside down several times, and adjust the amount of filler added to the zero line of the ruler; when measuring, first put the filler upside down in the top box, turn off the plug plate switch, open the bottom box lid, put the bread to be tested, cover the bottom, pull open the plug plate to let the filler fall naturally, and read the filler scale on the ruler, which is the actual measured volume of the bread.

[0069] When the volume of the bread to be tested is greater than 400mL, first open the bottom box, put in the 400mL standard module, cover the bottom box, open the top box cover and the plug board, put the filler in from the top box to the zero line of the ruler, cover the top cover, turn it upside down several times to eliminate dead corners and gaps, and adjust the amount of filler added to the zero line of the ruler; when measuring, first put the filler upside down in the top box, turn off the plug board switch, open the bottom box cover, take out the standard module, put in the bread to be tested, cover the bottom cover, pull open the plug board to let the filler fall naturally, and read the scale of the filler on the ruler, which is the actual measured volume of the bread.

[0070] The specific volume P of bread is calculated according to the formula:

[0071] P=V / m

[0072] Where:

[0073] P——specific volume of bread, in milliliters per gram (mL / g);

[0074] V——bread volume, in milliliters (mL);

[0075] M——bread mass, in grams (g).

[0076] The specific volume test results can be seen in Table 2;

[0077] 1.2. Texture

[0078] Use a texture analyzer to detect the texture profile of the bread. Cut the bread slices of uniform thickness of 5cm×5cm×2cm from the bread crumb after cooling, and use a cylindrical probe (P / 36R probe) to measure the texture of the bread slices. The test conditions are as follows: pre-test speed 1.00mm / s, test speed 2.00mm / s, post-test speed 5.00mm / s, compression degree 50%, trigger force 5.0g. Repeat the test at least 5 times for each group of bread, take the average value, and use hardness, elasticity, chewiness, cohesion, and adhesion as evaluation indicators.

[0079] The texture test results can be seen in Table 2;

[0080] Table 2 Specific volume and texture test results

[0081] sample <![CDATA[Specific volume / cm 3 / g]]> Hardness / N elasticity Chewability / N Cohesion Control <![CDATA[3.36±0.06 a ]]> <![CDATA[610.09±9.13 e ]]> <![CDATA[0.97±0.005 a ]]> <![CDATA[508.71±10.32 e ]]> <![CDATA[0.65±0.01 a ]]> B2 <![CDATA[4.33±0.03 e ]]> <![CDATA[459.34±17.85 c ]]> <![CDATA[1.05±0.095 a ]]> <![CDATA[364.44±68.02 cd ]]> <![CDATA[0.74±0.05 bc ]]> B4 <![CDATA[4.23±0.03 de ]]> <![CDATA[457.60±14.30 c ]]> <![CDATA[0.99±0.007 a ]]> <![CDATA[317.29±11.2 bc ]]> <![CDATA[0.70±0.006 ab ]]> C3B2 <![CDATA[3.93±0.02 b ]]> <![CDATA[578.35±1.58 d ]]> <![CDATA[0.97±0.005 a ]]> <![CDATA[403.56±12.33 d ]]> <![CDATA[0.72±0.02 ab ]]> C3B4 <![CDATA[4.88±0.08 g ]]> <![CDATA[378.52±34.12 b ]]> <![CDATA[0.97±0.006 a ]]> <![CDATA[257.86±14.25 b ]]> <![CDATA[0.71±0.02 ab ]]> C6B2 <![CDATA[4.03±0.02 bc ]]> <![CDATA[371.77±0.93 b ]]> <![CDATA[0.97±0.003 a ]]> <![CDATA[279.52±1.5 b ]]> <![CDATA[0.78±0.007 bc ]]> C6B4 <![CDATA[3.48±0.03 a ]]> <![CDATA[398.17±2.6 a ]]> <![CDATA[0.98±0.002 a ]]> <![CDATA[155.58±3.26 a ]]> <![CDATA[0.80±0.01 c ]]> C9B2 <![CDATA[4.66±0.02 f ]]> <![CDATA[372.58±7.19 d ]]> <![CDATA[1.00±0.02 a ]]> <![CDATA[436.83±20.25 de ]]> <![CDATA[0.76±0.02 bc ]]> C9B4 <![CDATA[4.13±0.08 cd ]]> <![CDATA[374.33±1.19 b ]]> <![CDATA[0.97±0.005 a ]]> <![CDATA[279.28±10.55 b ]]> <![CDATA[0.77±0.03 bc ]]>

[0082] Note: The same superscripts indicate no significant difference, while different superscripts indicate significant difference.

[0083] It can be seen from the data in Table 2 that the specific volume increases significantly after using red rice flour; by comparing the specific volumes of the control sample, B2, C3B2, C6B2, and C9B2, it can be seen that when the red rice flour is fixed at 5g, the specific volume increases proportionally with the addition of black red rose; the specific volume of the control sample, B4, C3B4, C6B4, and C9B4 also increases first, then decreases, and then increases again, so the data of C6B4 can be considered as an error.

[0084] The above analysis shows that the increase in specific volume of bread caused by dark red rose flour and red rice flour is positively correlated. When the amount of red rice flour used exceeds 5g, there is no necessary correlation between the specific volume of red rice flour and bread.

[0085] From the data in Table 2, it can be seen that red rice flour and dark red rose are beneficial to the softness of bread; when the dosage of the two reaches 7.5g and 10g, the softness no longer continues to improve;

[0086] From the data in Table 2, it can be seen that red rice flour and dark red rose have no clear effect on the elasticity;

[0087] It can be seen from the data in Table 2 that the chewiness and cohesion are significantly improved by the addition of red rice flour and dark red rose. From the result data, when the amount of dark red rose reaches about 15g, the chewiness is reduced to the lowest.

[0088] 3. Bread color

[0089] The L* value (brightness), a* value (yellow-green) and b* value (yellow-blue) of the bread crust and bread core are measured using a colorimeter. After the bread is cooled at room temperature, the bread crust and bread core are placed in the colorimeter to measure the L*, a* and b* values ​​of each sample, and the ΔE value is calculated according to the formula.

[0090] ΔE=√(2&(L^*-L)^2+(a^*-a)^2+(b^*-b)^2)

[0091] Where:

[0092] ΔE-color difference (the larger the value, the greater the color difference);

[0093] L*-brightness value difference (when the value is positive, it means it is lighter than the standard color plate; when the value is negative, it means it is darker than the standard color plate);

[0094] a*-the difference between red and green values ​​(the larger the value, the redder it is);

[0095] b*-the difference between yellow and blue values ​​(the larger the value, the yellower it is).

[0096] The test results can be seen in Table 3;

[0097] Table 3 Color test results

[0098] Crust L* a* b* ΔE Control <![CDATA[71.7±0.02 f ]]> <![CDATA[2.22±0.06 b ]]> <![CDATA[30.2±0.04 g ]]> <![CDATA[33.0±0.03 a ]]> B2 <![CDATA[58.6±0.04 b ]]> <![CDATA[3.48±0.00 d ]]> <![CDATA[20.3±0.03 c ]]> <![CDATA[36.9±0.05 b ]]> B4 <![CDATA[52.9±2.41 bc ]]> <![CDATA[5.62±0.42 f ]]> <![CDATA[16.0±0.03 a ]]> <![CDATA[40.8±2.19 c ]]> C3B2 <![CDATA[64.8±0.02 e ]]> <![CDATA[-0.21±0.04 a ]]> <![CDATA[34.8±0.00 h ]]> <![CDATA[40.7±0.01 c ]]> C3B4 <![CDATA[54.7±0.05 c ]]> <![CDATA[2.88±0.02 c ]]> <![CDATA[24.0±0.05 e ]]> <![CDATA[42.0±0.07 c ]]> C6B2 <![CDATA[45.8±0.04 a ]]> <![CDATA[4.54±0.04 e ]]> <![CDATA[19.1±0.01 b ]]> <![CDATA[48.3±0.04 ef ]]> C6B4 <![CDATA[60.0±0.02 d ]]> <![CDATA[-0.04±0.00 a ]]> <![CDATA[38.6±0.04 i ]]> <![CDATA[46.9±0.04 de ]]> C9B2 <![CDATA[51.7±0.02 b ]]> <![CDATA[2.74±0.03 c ]]> <![CDATA[26.5±0.00 f ]]> <![CDATA[45.8±0.02 d ]]> C9B4 <![CDATA[45.8±0.05 a ]]> <![CDATA[3.57±0.03 d ]]> <![CDATA[22.0±0.02 d ]]> <![CDATA[49.2±0.05 f ]]> Bread crumbs L* a b ΔE Control <![CDATA[51.6±0.04 i ]]> 16.5±0.04d 34.5±0.07d 53.1±0.02a B2 <![CDATA[37.4±0.01 f ]]> 18.3±0.01g 24.4±3.37ab 60.9±1.05d B4 <![CDATA[42.7±0.01 h ]]> 14.7±0.03a 27.1±0.02bc 57.0±0.02b C3B2 <![CDATA[34.1±0.01 e ]]> 17.5±0.04f 25.3±0.02abc 57.0±0.02b C3B4 33.4±0.01d 16.9±0.06e 24.9±0.06ab 64.2±0.04f C6B2 31.2±0.00a 15.6±0.04c 22.4±0.00a 65.0±0.01f C6B4 33.1±0.01c 15.2±0.04b 21.8±0.02a 63.0±0.01e C9B2 39.3±0.01g 15.5±0.04c 28.6±0.08c 59.9±0.03c C9B4 32.1±0.02b 15.3±0.01b 23.9±0.06ab 64.6±0.04f

[0099] Note: Different superscript letters in the same column of data indicate significant differences among groups (p<0.05), where a is the minimum value.

[0100] 4. Sensory evaluation

[0101] According to the sensory evaluation of the national standard GB / T 14611-2008 and with appropriate modifications based on the actual situation, the sensory evaluation was carried out at room temperature. The evaluation criteria can be found in Table 4, and the test results can be found in Table 5.

[0102] Table 4 Sensory evaluation score table

[0103]

[0104]

[0105] Table 5 Sensory evaluation test results

[0106] Group volume Bread shape Epidermal texture Texture Flexibility Taste Control <![CDATA[12.25±0.56 c ]]> <![CDATA[11.00±0.38 c ]]> <![CDATA[7.88±0.74 abc ]]> <![CDATA[12.75±1.13 bc ]]> <![CDATA[13.13±1.27 a ]]> <![CDATA[8.75±1.26 a ]]> B2 <![CDATA[12.5±0.42 c ]]> <![CDATA[9.50±0.71 bc ]]> <![CDATA[9.13±1.09 c ]]> <![CDATA[14.63±0.92 c ]]> <![CDATA[14.5±1.3 a ]]> <![CDATA[13.00±1.54 b ]]> B4 <![CDATA[12.63±0.42 c ]]> <![CDATA[10.5±0.71 c ]]> <![CDATA[8.50±0.94 bc ]]> <![CDATA[13.63±0.71 bc ]]> <![CDATA[15.38±0.75 a ]]> <![CDATA[11.38±1.40 ab ]]> C3B2 <![CDATA[11.38±0.42 c ]]> <![CDATA[10.63±0.78 c ]]> <![CDATA[8.38±1.16 bc ]]> <![CDATA[13.50±0.57 bc ]]> <![CDATA[15.88±0.80 a ]]> <![CDATA[12.63±1.16 b ]]> C3B4 <![CDATA[11.25±0.41 c ]]> <![CDATA[11.50±0.91 c ]]> <![CDATA[8.5±0.87 bc ]]> <![CDATA[13.88±0.40 bc ]]> <![CDATA[13.63±1.56 a ]]> <![CDATA[12.5±1.18 b ]]> C6B2 <![CDATA[9±0.42 b ]]> <![CDATA[7.13±0.93 a ]]> <![CDATA[5.25±1.24 ab ]]> <![CDATA[13.13±0.81 bc ]]> <![CDATA[14.5±1.15 a ]]> <![CDATA[14.00±1.46 b ]]> C6B4 <![CDATA[8.75±0.49 ab ]]> <![CDATA[6.5±0.91 a ]]> <![CDATA[4.88±1.17 a ]]> <![CDATA[12.75±1.26 bc ]]> <![CDATA[14.38±1.28 a ]]> <![CDATA[12.88±1.48 b ]]> C9B2 <![CDATA[7.5±0.42 a ]]> <![CDATA[6.13±0.67 a ]]> <![CDATA[4.88±0.83 a ]]> <![CDATA[9.75±1.10 a ]]> <![CDATA[14.75±0.70 a ]]> <![CDATA[13.75±0.59 b ]]> C9B4 <![CDATA[8.88±0.61 ab ]]> <![CDATA[7.75±0.82 ab ]]> <![CDATA[5.63±1.13 ab ]]> <![CDATA[10.88±1.33 ab ]]> <![CDATA[15.13±0.69 a ]]> <![CDATA[13.13±0.81 b ]]>

[0107] The following conclusions can be drawn from sensory testing:

[0108] The appropriate amount of red rice flour can improve the appearance of the bread, improve the surface texture, grain structure, softness and elasticity, and significantly improve the taste; the dark red rose powder will weaken the volume, appearance, texture, grain and other properties to a certain extent, and the improvement in softness and elasticity is not obvious, but there is a certain improvement in taste; This shows that the reasonable amount of rose pollen can make the bread have a pleasant floral fragrance and improve the taste, but the texture data of the bread will be weakened, so the amount of rose pollen used needs to be controlled.

Claims

1. A bread, characterized in that: The bread is made from wheat flour, red rice flour, eggs, salt, sugar, yeast and butter; Among them, the weight ratio of wheat flour to red rice flour is 227.5-250:5-10.

2. The bread according to claim 1, characterized in that The raw materials for making the bread also include dark red roses, and the weight ratio of the wheat flour to the dark red roses is 227.5-242.7:5-22.

5.

3. The bread according to claim 1, characterized in that The particle size of the red rice flour is ≤75 μm.

4. The bread according to claim 2, characterized in that: The particle size of the dark red rose is ≤50 μm.

5. The bread according to claim 1, characterized in that The weight ratio of the wheat flour, milk, salt, sugar, yeast and butter is: 227.5-250: 25-35: 1.5-2.5: 20-30: 4-6: 18-22.

6. The bread according to claim 5, characterized in that The weight ratio of the wheat flour, eggs, salt, sugar, yeast and butter is: 227.5-250:30:2:15:5:

20.

7. A method for preparing bread according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: Put all ingredients except butter, yeast and salt into a dough mixing bowl, mix until there is no dry powder, add yeast, mix evenly, add salt, and stir until a film forms; Step 2: Add softened butter to the dough and knead until the surface of the bowl is smooth and film-forming; Step 3: Move the dough to a turnover box and let it rise at room temperature for 0.8 to 1.2 hours, with the volume expanding by 0.8 to 1.2 times; Step 4: Take out the dough, pat it gently to release the air, divide it into 100g / piece of dough, roll it into balls and let it relax for a while; Step 5: The dough is subjected to secondary fermentation in a fermentation cabinet at 34-36° C. and a relative humidity of 80-90 wt % for 0.8-1.2 h, and the volume expansion increases by 0.8-1.2 times; Step 6: Put the dough into the oven, steam it for 4 to 6 seconds, with the upper and lower fire at 185 to 195°C, bake it for 18 to 22 minutes, and get the bread after cooling to room temperature.

8. The preparation method according to claim 7, characterized in that: The steps include: Step 1: Put all ingredients except butter, yeast and salt into a dough mixing bowl, mix until there is no dry powder, add yeast, mix evenly, add salt, and stir until a film forms; Step 2: Add softened butter to the dough and knead until the surface of the bowl is smooth and film-forming; Step 3: Move the dough to a turnover box and let it rise at room temperature for 1 hour until its volume doubles; Step 4: Take out the dough, pat it gently to release the air, divide it into 100g / piece of dough, roll it into balls and relax it for 15 minutes; Step 5: The dough is subjected to secondary fermentation in a fermentation cabinet at 35° C. and a relative humidity of 85 wt % for 1 hour, and the volume expands by 1 time; Step 6: Put the dough into the oven, steam it for 5 seconds, bake it at 190℃ for 20 minutes, and get the bread after cooling to room temperature.

9. The preparation method according to claim 7 or 8, characterized in that: The ratio of flour to water in step 1 is 227.5-250:150.

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