Corn steamed bun with high corn flour content and preparation method thereof

Abstract

The invention discloses a corn steamed bun with high corn flour content and a preparation method of the corn steamed bun, roller-milled corn flour is prepared by adopting a roller milling method, and the roller-milled corn flour and wheat flour are compounded to prepare the corn steamed bun. According to the corn steamed bun and the preparation method thereof, common corn or waxy corn kernels are used as raw materials to prepare the roller-milled corn flour, the roller-milled corn flour and the wheat flour are compounded to prepare the corn steamed bun, and the prepared corn steamed bun does not contain additives and chemical gum substances; the corn flour has good palatability, nutrient substances are completely reserved, and the nutritional property of the processed corn flour is not changed. Compared with a corn steamed bun prepared by grinding corn flour with a grinder, the corn steamed bun prepared by the method disclosed by the invention has larger specific volume and better texture characteristics. The addition amount of the corn flour in the prepared corn steamed bun can reach 40%, and under the condition of the same corn flour addition amount, the corn steamed bun has larger specific volume and better texture characteristics compared with the corn steamed bun prepared by grinding the corn flour through a grinder.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a corn steamed bread with a high corn flour content and a preparation method thereof. Background Art

[0002] In recent years, with the demand for people to maintain health and the change of dietary structure, adding coarse grains to staple food or directly eating coarse grains as staple food has become a new trend of staple food. Corn is the most widely planted and produced food crop in the world. Corn is rich in unsaturated fatty acids and linoleic acid, and its vitamin content is 5-10 times that of rice and wheat. Linoleic acid and vitamin E can reduce serum cholesterol and delay brain function degeneration; it is rich in trace elements selenium and magnesium, and its carotene content is more than 5 times that of soybeans. Selenium can promote the decomposition of peroxides in the human body, inhibit the oxygen supply of tumors, and has a certain anti-cancer effect; it is rich in dietary fiber, zeaxanthin, and riboflavin. Dietary fiber can promote intestinal peristalsis, inhibit the increase of blood sugar after meals and the absorption of fat, and can prevent colon cancer, age-related macular degeneration, etc. It can be seen that corn has rich nutritional value and functional characteristics. Strengthening the use of corn in the field of food processing is conducive to the rational development of corn resources.

[0003] Corn flour is a powdered corn prepared by grinding corn with a specific tool. The current method of making corn flour is milling or stone milling. The output and efficiency of stone milling are low, so most corn flour products are milling. The force of the mill is shearing. The high-speed rotating blade acts on any part of the complete corn endosperm mass or corn endosperm cell structure. The strong shearing action causes the corn endosperm particles to break from the action site, thus forming a smooth cross-section. The mill's crushing process acts on the cell wall and the starch and protein matrix in the cell structure at the same time, destroying the cell structure, thereby increasing the content of damaged starch.

[0004] At present, corn flour is widely used in the food industry, such as corn steamed bread, corn noodles, corn grits porridge, corn steamed cakes, etc. However, excessive addition of corn flour will lead to more quality problems in food, such as poor palatability, low fluffiness, and increased crumbing, etc. This is mainly because corn itself does not contain gluten protein and has destroyed the gluten structure to a certain extent. Therefore, most corn steamed breads on the market have corn flour added between 20-25% to prevent the quality of the steamed bread from deteriorating.

[0005] In order to improve the applicability of corn flour, most products on the market choose to add edible gum to interact with amylose, increase the viscosity and consistency coefficient of the composite gel system, and thus increase the content of corn flour in corn bread with the same texture characteristics. However, as consumers' demand for pure natural food increases, the addition of edible gum will reduce consumers' desire to buy, and the acceptance of the product will decrease accordingly. There is also a method of modifying corn flour using dietary fiber degrading enzymes to reduce the competitive water absorption of insoluble dietary fiber with protein in the steamed bread system and increase the gluten content in the steamed bread system. Although this method greatly increases the amount of corn flour added, it destroys the dietary fiber in the corn flour, resulting in a decrease in the nutritional quality of the corn flour.

[0006] Therefore, in order to give full play to the nutritional and health value of corn flour, improve the utilization of corn flour, and increase the amount of corn flour added to steamed bread, it is necessary to seek new corn flour processing technology and improve the quality of corn flour. Summary of the invention

[0007] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a roller mill grinding method for corn flour, and to use roller mill corn flour instead of grinded corn flour by a crusher to add it to the preparation of corn steamed buns, so as to solve the problem that the corn flour obtained by current corn flour processing is added in a low amount in staple food, and excessive addition of corn flour leads to a rapid decline in the quality of corn steamed buns.

[0008] In order to achieve the above object, the present invention first provides a method for preparing corn steamed bread with high corn flour content.

[0009] (1) compounding roller-milled corn flour and wheat flour to obtain compound corn flour, wherein the roller-milled corn flour accounts for 30-40% of the mass of the compound corn flour;

[0010] (2) putting the compound corn flour described in step (1) into a dough mixer, mixing it with dry yeast, adding water and kneading the dough to obtain the compound corn flour dough before proofing;

[0011] (3) proofing the composite corn flour dough described in step (2) to obtain a proofed composite corn flour dough;

[0012] (4) rolling, kneading and shaping the composite corn flour dough after the primary proofing in step (3), and performing secondary proofing to obtain a raw corn steamed bread dough;

[0013] (5) Steaming the raw corn steamed bun embryos prepared in step (4) to obtain corn steamed buns.

[0014] In one embodiment of the present invention, the method for preparing roller-milled corn flour comprises the following steps:

[0015] S1. Select corn kernels with full grains and no obvious damage, wash them, and dry them until the moisture content is 11-14%, thereby obtaining corn kernels after drying;

[0016] S2, adding water to the corn kernels dried in step S1 for conditioning, so that the moisture content of the conditioned kernels is 18-23%, thereby obtaining conditioned corn kernels;

[0017] S3, peeling and embryo-forming the conditioned corn kernels obtained in step S2, and then sieving them with a sieve with a mesh number of 4 to 8 to obtain corn grits;

[0018] S4, performing roller milling processing on the corn grits obtained in step S3, grinding the corn grits with a roller mill to obtain roller milled corn flour;

[0019] S5. Screening the roller-milled corn flour obtained in step S4 to obtain relatively uniform roller-milled corn flour.

[0020] In one embodiment of the present invention, in step S1, the type of corn kernels is common corn or glutinous corn.

[0021] In one embodiment of the present invention, in step S1, the specific condition for drying the corn kernels is drying them in a forced air drying oven at a temperature of 40-50° C. for 16-20 hours.

[0022] In one embodiment of the present invention, in step S2, the specific steps of the conditioning treatment are: placing corn kernels in a sealed bag, sealing the bag after adding water, shaking the sealed bag to allow the kernels to fully and evenly contact with the water, and placing the bag at 50-55° C. for immersion for 25-30 minutes.

[0023] In one embodiment of the present invention, in step S3, the peeling and embryo processing of the tempered corn kernels is carried out by using a roller mill, the peeling and embryo processing frequency is 25-30 Hz, the rotation speed is 650 r / min, the spacing between the rollers is 0.45-0.5 mm, and the number of grinding times is 1-3 times.

[0024] In one embodiment of the present invention, in step S3, when the crushed corn grits are screened, they are first screened using a 4-mesh sieve to remove larger corn endosperm particles, and then further screened using an 8-mesh sieve to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh sieve is controlled to be 95-100%, and the retention rate on the 8-mesh sieve is controlled to be 95-100%.

[0025] In one embodiment of the present invention, in step S4, the frequency of the roller mill is set to 25-50 Hz, and the number of grinding times is 1-5 times.

[0026] In one embodiment of the present invention, in step S5, the mesh size of the sieve during the sieving process is 60 meshes.

[0027] In one embodiment of the present invention, in step (2), the amount of dry yeast added is 1% of the mass of the compound corn flour, the amount of water added is 45-48% of the mass of the compound corn flour, and the kneading time of the dough mixer is 5-8 minutes.

[0028] In one embodiment of the present invention, in step (3), the first proofing time of the compound corn flour dough is 8-10 minutes.

[0029] In one embodiment of the present invention, in the step (4), the composite corn flour dough is rolled 8-10 times.

[0030] In one embodiment of the present invention, in the step (5), the raw corn steamed bun embryos are put into a pot with cold water and steamed for 15-20 minutes.

[0031] The present invention provides corn steamed bread prepared according to the method.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention uses common corn or glutinous corn kernels as raw materials to prepare roller-milled corn flour, and mixes the roller-milled corn flour with wheat flour to prepare corn steamed bread. The prepared corn steamed bread does not contain additives and chemical gum substances; it has good palatability, and the nutrients are relatively completely retained. The nutritional properties of the corn flour remain unchanged after processing.

[0034] (2) Compared with corn flour ground by a crusher, the particle size of roller-ground corn flour is relatively large, and the large particle size portion accounts for a larger proportion, and the content of damaged starch is also relatively low. After the roller-ground corn flour and wheat flour are compounded to prepare corn steamed bread, on the one hand, the proportion of corn starch entering the gluten of the steamed bread is relatively low, which reduces the degree of damage to the gluten structure. On the other hand, the lower content of damaged starch can reduce the competition for water during the gluten formation period of the steamed bread, which is more conducive to the formation of gluten.

[0035] (3) Compared with the corn steamed bread prepared by grinding corn flour with a pulverizer, the corn steamed bread prepared by the method of the present invention has a larger specific volume and better texture characteristics. The specific volume of the corn steamed bread of the present invention exceeds 2.0.

[0036] (4) The amount of corn flour added in the corn bread prepared by the present invention can reach 40%, and under the condition of the same amount of corn flour added, the corn bread of the present invention has a larger specific volume and better texture characteristics than the corn bread prepared by grinding corn flour with a pulverizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a comparison diagram of the corn flour particle size distribution of Examples 1-5;

[0038] Figure 2 This is a comparison diagram of the corn flour particle size distribution of Comparative Examples 1-3 and Comparative Example 5;

[0039] Figure 3 This is a comparison of the damaged starch in corn flour of Examples 1-5, Comparative Examples 1-3 and Comparative Example 5;

[0040] Figure 4 The SEM observation results of corn flour of Implementation 1 (right) and Comparative Example 1 (left);

[0041] Figure 5 This is a comparison diagram of the steamed bread specific volumes of Examples 1-3 and Comparative Examples 1-5;

[0042] Figure 6 The figure is a comparison result of the steamed bread hardness of Examples 2 and 3 and Comparative Examples 1-5;

[0043] Figure 7 This is a comparison chart of the recovery of steamed bread of Examples 2 and 3 and Comparative Examples 1-5;

[0044] Figure 8 The graph is a comparison of the chewiness of the steamed bread of Examples 2 and 3 and Comparative Examples 1-5. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the embodiments. It should be understood that these embodiments are only for illustrative purposes and do not limit the scope of protection of the present invention.

[0046] Source of raw materials

[0047] The corn kernel type of the present invention is common corn, which is provided by Jiangsu Academy of Agricultural Sciences.

[0048] Detection Methods

[0049] 1. Particle size distribution determination:

[0050] Weigh 100 mg of wheat endosperm powder sample and place it in a 2 mL centrifuge tube. Add about 1.5 mL of distilled water to the centrifuge tube and shake it thoroughly to disperse the wheat endosperm powder particles evenly. According to the prompt of the particle size analyzer, use a rubber dropper to drop the mixed sample suspension dropwise into the sample dish that has been added with 500 mL of distilled water in advance until the sample particle distribution conforms to the normal distribution, and stop adding samples. Use the particle size analyzer for automatic measurement to determine the particle size of the sample.

[0051] 2. Determination of damaged starch:

[0052] The damaged starch was determined according to GBT9826-2008 (amylase method).

[0053] 3.SEM observation:

[0054] Corn flour was observed using a SU8100 cold field emission scanning electron microscope.

[0055] 4. Specific volume determination:

[0056] The mass of the steamed buns was determined after cooling, and the volume of the steamed buns was determined using the volume displacement method (using millet instead of steamed buns).

[0057] The specific volume was calculated according to the following formula:

[0058] Specific volume (mL / g) = steamed bread volume (mL) / steamed bread mass (g)

[0059] 5. Texture determination:

[0060] The texture of steamed bread was measured using a texture analyzer. The probe model was P / 36R. The speeds before, during and after the test were 1 mm / s, 0.8 mm / s and 1.0 mm / s, the trigger force was 30 g, the deformation degree was 50%, and the secondary compression time interval was 5 s.

[0061] Example 1

[0062] A method for preparing roller-milled corn flour comprises the following steps:

[0063] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature at 50°C, and soak for 25 minutes to obtain the tempered corn kernels.

[0064] S2. The corn kernels obtained in step S1 are subjected to roller milling, peeling and embryo preparation. After being peeled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, with the pass rate under the 4-mesh sieve being controlled to be 95-100%, and the retention rate on the 8-mesh sieve being controlled to be 95-100%.

[0065] S3, the corn grits obtained in step S2 are subjected to roller milling, and the roller mill is used to grind the corn grits, the frequency is set to 30 Hz, and the grinding number is 1. The roller milled corn flour is sieved, and a sieve with a mesh size of 60 is used to obtain a relatively uniform roller milled corn flour.

[0066] A method for preparing corn steamed bread comprises the following steps:

[0067] (1) Take roller-milled corn flour and wheat flour and mix them to obtain compound corn flour, the proportion of corn flour is 40%. Put the compound corn flour into a dough mixer, mix it with dry yeast, add water and knead the dough. The amount of dry yeast added is 1% of the mass of the compound corn flour, the amount of water added is 45% of the mass of the compound corn flour, and the kneading time of the dough mixer is 5 minutes.

[0068] (2) The mixed corn flour dough is proofed once for 8 minutes to obtain the corn flour dough; the corn flour dough is rolled, kneaded and shaped for 8 times and proofed twice to obtain the raw corn bread. The raw corn bread is steamed for 15 minutes to obtain the corn bread.

[0069] Example 2

[0070] A method for preparing roller-milled corn flour comprises the following steps:

[0071] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature to 55°C, and soak for 28 minutes to obtain the tempered corn kernels.

[0072] S2. The corn kernels obtained in step S1 are subjected to roller milling, peeling and embryo preparation. After being peeled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh sieve is controlled to be 95-100%, and the retention rate on the 8-mesh sieve is controlled to be 95-100%, thereby obtaining corn grits.

[0073] S3, the corn grits obtained in step S2 are subjected to roller milling and milling, the roller mill milling machine is used to grind the corn grits, the frequency of the roller mill milling machine is set to 40 Hz, and the number of grinding times is 2. The roller milled corn flour is sieved, and a sieve mesh with a mesh number of 60 is used to obtain a relatively uniform roller milled corn flour.

[0074] A method for preparing corn steamed bread comprises the following steps:

[0075] (1) Take roller-milled corn flour and wheat flour and mix them to obtain compound corn flour, the proportion of corn flour is 35%. Put the compound corn flour into a dough mixer, mix it with dry yeast, add water and knead the dough. The amount of dry yeast added is 1%, the amount of water added is 46%, and the kneading time of the dough mixer is 6 minutes.

[0076] (2) The mixed corn flour dough is proofed once for 8 minutes to obtain the corn flour dough; the corn flour dough is rolled, kneaded and shaped for 8 times and proofed twice to obtain the raw corn bread. The raw corn bread is steamed for 15 minutes to obtain the corn bread.

[0077] Example 3

[0078] A method for preparing roller-milled corn flour comprises the following steps:

[0079] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature to 55°C, and soak for 30 minutes to obtain the tempered corn kernels.

[0080] S2. The corn kernels obtained in step S1 are subjected to roller milling, peeling and embryo preparation. After being peeled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh sieve is controlled to be 95-100%, and the retention rate on the 8-mesh sieve is controlled to be 95-100%, thereby obtaining corn grits.

[0081] S3, the corn grits obtained in step S2 are subjected to roller milling, and the roller mill is used to grind the corn grits, the frequency of the roller mill is set to 50 Hz, and the number of grinding times is 3. The roller milled corn flour is sieved, and a sieve with a mesh size of 60 is used to obtain a relatively uniform roller milled corn flour.

[0082] A method for preparing corn steamed bread comprises the following steps:

[0083] (1) Take roller-milled corn flour and wheat flour and mix them to obtain compound corn flour, the proportion of corn flour is 35%. Put the compound corn flour into a dough mixer, mix it with dry yeast, add water and knead the dough. The amount of dry yeast added is 1%, the amount of water added is 48%, and the kneading time of the dough mixer is 8 minutes.

[0084] (2) The mixed corn flour dough is proofed once for 10 minutes to obtain the composite corn dough, and the composite corn flour dough is rolled, kneaded and shaped for 8 times, and proofed twice to obtain the raw corn steamed buns. The raw corn steamed buns are steamed in a pot for 20 minutes to obtain corn steamed buns.

[0085] Example 4

[0086] A method for preparing roller-milled corn flour comprises the following steps:

[0087] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature to 55°C, and soak for 30 minutes to obtain the tempered corn kernels.

[0088] S2. The corn kernels obtained in step S1 are subjected to roller milling, peeling and embryo preparation. After being peeled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh sieve is controlled to be 95-100%, and the retention rate on the 8-mesh sieve is controlled to be 95-100%, thereby obtaining corn grits.

[0089] S3, the corn grits obtained in step S2 are subjected to roller milling and milling, the roller mill milling machine is used to grind the corn grits, the frequency of the roller mill milling machine is set to 50 Hz, and the number of grinding times is 4. The roller milled corn flour is sieved, and a sieve mesh with a mesh number of 60 is used to obtain a relatively uniform roller milled corn flour.

[0090] A method for preparing corn steamed bread comprises the following steps:

[0091] (1) The roller-milled corn flour prepared according to the above method is mixed with wheat flour to obtain compound corn flour, wherein the proportion of corn flour is 30%. The compound corn flour is put into a dough mixer, mixed with dry yeast, and water is added to knead the dough. The amount of dry yeast added is 1%, the amount of water added is 48%, and the kneading time of the dough mixer is 8 minutes.

[0092] (2) The mixed corn flour dough is proofed once for 10 minutes. After the proofing, the obtained corn flour dough is rolled, kneaded and shaped for 8 times, and proofed twice to obtain corn steamed buns. The corn steamed buns are steamed for 20 minutes to obtain corn steamed buns.

[0093] Example 5

[0094] A method for preparing roller-milled corn flour comprises the following steps:

[0095] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature to 55°C, and soak for 30 minutes to obtain the tempered corn kernels.

[0096] S2. The corn kernels obtained in step S1 are subjected to roller milling, peeling and embryo preparation. After being peeled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh sieve is controlled to be 95-100%, and the retention rate on the 8-mesh sieve is controlled to be 95-100%, thereby obtaining corn grits.

[0097] S3, the corn grits obtained in step S2 are subjected to roller milling and milling, the roller mill milling machine is used to grind the corn grits, the frequency of the roller mill milling machine is set to 50 Hz, and the number of grinding times is 5. The roller milled corn flour is sieved, and a sieve with a mesh size of 60 is used to obtain a relatively uniform roller milled corn flour.

[0098] A method for preparing corn steamed bread comprises the following steps:

[0099] (1) The roller-milled corn flour prepared according to the above method is mixed with wheat flour to obtain compound corn flour, wherein the proportion of corn flour is 40%. The compound corn flour is put into a dough mixer, mixed with dry yeast, and water is added to knead the dough. The amount of dry yeast added is 1%, the amount of water added is 48%, and the kneading time of the dough mixer is 8 minutes.

[0100] (2) The mixed corn flour dough is proofed once for 10 minutes. After the proofing, the obtained corn flour dough is rolled, kneaded and shaped for 8 times, and proofed twice to obtain corn steamed buns. The corn steamed buns are steamed for 20 minutes to obtain corn steamed buns.

[0101] Comparative Example 1

[0102] The difference between Comparative Example 1 and Example 2 is that the corn flour is prepared by a pulverizer, and the amount of corn flour added to the corn buns is 20% of the weight of the composite corn flour.

[0103] A method for preparing corn flour ground by a pulverizer comprises the following steps:

[0104] S1. Select corn kernels with full grains and no obvious damage, wash and dry the corn kernels until the moisture content is 14%, add water to the corn kernels after drying for conditioning, put the corn kernels in a sealed bag, add 50% water, seal the bag after adding water, shake the sealed bag to make the kernels fully and evenly contact with water, control the grain temperature at 50°C, and soak for 25 minutes to obtain the tempered corn kernels.

[0105] S2. Using a degerming machine to dehull and germinate the tempered corn kernels obtained in step S1. After being dehulled by air separation, the kernels are first sieved with a 4-mesh sieve to remove larger corn endosperm particles, and then further sieved with an 8-mesh sieve to obtain relatively uniform corn grits particles, with a pass rate of 95-100% under the 4-mesh sieve and a retention rate of 95-100% on the 8-mesh sieve.

[0106] S3, grinding the corn grits obtained in step S2 with a pulverizer, the pulverizer frequency is set to 50 Hz, the grinding time is 5 seconds, and the pulverizer-ground corn flour is obtained. The pulverizer-ground corn flour is sieved through a 60-mesh sieve to obtain relatively uniform pulverizer-ground corn flour.

[0107] Comparative Example 2

[0108] The difference between Comparative Example 2 and Comparative Example 1 is that in the preparation method of grinding corn flour with a pulverizer, the grinding time is 10 seconds.

[0109] In the preparation method of corn steamed bread, the added amount of corn flour is 25% of the weight of the composite corn flour.

[0110] Comparative Example 3

[0111] The difference between Comparative Example 3 and Comparative Example 1 is that in the preparation method of grinding corn flour with a pulverizer, the grinding time is 15 seconds.

[0112] In the preparation method of corn steamed bread, the added amount of corn flour is 25% of the weight of the composite corn flour.

[0113] Comparative Example 4

[0114] The difference between Comparative Example 4 and Comparative Example 1 is that in the preparation method of grinding corn flour with a pulverizer, the grinding time is 15 seconds.

[0115] In the preparation method of corn steamed bread, the added amount of corn flour is 30% of the weight of the composite corn flour.

[0116] Comparative Example 5

[0117] The difference between Comparative Example 5 and Comparative Example 1 is that in the preparation method of grinding corn flour with a pulverizer, the grinding time is 25 seconds.

[0118] In the preparation method of corn steamed bread, the added amount of corn flour is 30% of the weight of the composite corn flour.

[0119] 1. Particle size distribution

[0120] Determine the particle size distribution of Examples 1-5 and Comparative Examples 1-3 and Comparative Example 5, and obtain Figure 1 , Figure 2 The particle size distribution curve shows that the particle size of the roller-milled corn flour in the embodiment and the pulverizer-milled corn flour in the comparative example decreases with the increase of the pulverizing time, but the particle size distribution of the roller-milled corn flour in the embodiment is significantly larger than that of the pulverizer-milled corn flour in the comparative example, and it can be seen from the figure that the part of the roller-milled corn flour with a small particle size in the embodiment is significantly less than that of the pulverizer-milled corn flour in the comparative example. The larger particle size can reduce the proportion of corn starch entering the steamed bun gluten, so that the degree of gluten structure destruction becomes lower.

[0121] 2. Damaged starch

[0122] Determine the damaged starch of Examples 1-5 and Comparative Examples 1-3 and Comparative Example 5, and obtain Figure 3 The damaged starch content of the roller-milled corn flour in the embodiment and the pulverizer-milled corn flour in the comparative example increases with the increase of the number of milling times and the milling time. The damaged starch content of the roller-milled corn flour in the embodiment at each stage is generally lower than that of the pulverizer-milled corn flour in the comparative example at the same stage. A lower damaged starch content can reduce the competition for water during the formation of steamed bun gluten, which is more conducive to the formation of gluten.

[0123] 3.SEM observation

[0124] The fracture surface of the comparative example is relatively flat, which is caused by the shearing action of the blade. The fracture surface of the embodiment is relatively rough, and cracks appear in the middle of the particles, which is caused by the squeezing and scraping action of the roller.

[0125] 4. Specific volume determination

[0126] Specific volume is an important index for evaluating the quality of steamed bread. The specific volume (height-to-diameter ratio) of steamed bread in Examples 1-3 and Comparative Examples 1-5 was measured. It was observed that the specific volume of corn steamed bread in the examples was higher than that in Comparative Examples 1-5. In Comparative Examples 1 to 5, the amount of corn flour added by the pulverizer was gradually increased from 20% to 30%, but the specific volume of the prepared corn steamed bread was gradually reduced, indicating that the increase in corn flour content would lead to the destruction of the gluten network structure in the corn steamed bread. In Examples 1-3, the amount of corn flour added by roller mill was gradually reduced from 40% to 35%. When the amount of corn flour added in the examples was significantly higher than that in the comparative examples, the specific volume of the steamed bread in Examples 1-3 was higher than 2.0. The specific volume of other examples could also reach this standard, indicating that the addition of roller mill corn flour could improve the network structure of gluten in corn steamed bread, making the edible quality of the prepared corn steamed bread higher.

[0127] 5. Texture analysis

[0128] The texture characteristics of steamed buns can reflect the quality differences of steamed buns to a certain extent. In the texture data, the hardness and chewiness of steamed buns are negatively correlated with the quality of steamed buns. The softness of steamed buns within a certain range is related to smaller hardness and chewiness values, while the resilience of steamed buns is positively correlated with the quality of steamed buns. The textures of Examples 1-3 and Comparative Examples 1-5 were measured. The hardness and chewiness of the corn steamed buns in Examples 1-3 were less than those of the corn steamed buns in Comparative Examples 1-5, while the resilience was higher than that of the corn steamed buns in Comparative Examples. The texture characteristics of other examples also conform to this rule, which shows that the corn steamed buns made from roller-milled corn flour have better texture characteristics and better steamed bun quality.

[0129] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing corn steamed bread with high corn flour content, characterized in that: The following steps are involved: (1) compounding roller-milled corn flour and wheat flour to obtain compound corn flour, wherein the roller-milled corn flour accounts for 30-40% of the mass of the compound corn flour; (2) putting the compound corn flour described in step (1) into a dough mixer, mixing it with dry yeast, adding water and kneading the dough to obtain the compound corn flour dough before proofing; (3) proofing the composite corn flour dough described in step (2) to obtain a proofed composite corn flour dough; (4) rolling, kneading and shaping the composite corn flour dough after the primary proofing in step (3), and performing secondary proofing to obtain a raw corn steamed bun dough; (5) Steaming the raw corn steamed bun embryos prepared in step (4) to obtain corn steamed buns.

2. The preparation method according to claim 1, characterized in that: The roller mill corn flour is prepared by the following steps: S1. Select corn kernels with full grains and no obvious damage, wash them, and dry them until the moisture content is 11-14%, thereby obtaining corn kernels after drying; S2, adding water to the corn kernels dried in step S1 for conditioning, so that the moisture content of the conditioned kernels is 18-23%, thereby obtaining conditioned corn kernels; S3, peeling and embryo-forming the conditioned corn kernels obtained in step S2, and then sieving them with a sieve with a mesh number of 4 to 8 to obtain corn grits; S4, performing roller milling processing on the corn grits obtained in step S3, grinding the corn grits with a roller mill to obtain roller milled corn flour; S5. The roller-milled corn flour obtained in step S4 is sieved through a 60-mesh screen to obtain relatively uniform roller-milled corn flour.

3. The preparation method according to claim 2, characterized in that: In the step S1, the type of the corn kernels is common corn or glutinous corn, and the specific condition for drying the corn kernels is drying them in a forced air drying oven at a temperature of 40-50° C. for 16-20 hours.

4. The preparation method according to claim 2, characterized in that: In step S2, the specific steps of the conditioning treatment are: placing the corn kernels in a sealed bag, sealing the bag after adding water, shaking the sealed bag to allow the kernels to fully and evenly contact with the water, and soaking the bag at 50-55° C. for 25-30 minutes.

5. The preparation method according to claim 2, characterized in that: In step S3, the peeling and embryo preparation of the conditioned corn kernels is carried out by using a roller mill, and when the crushed corn grits are screened, they are first screened by using a 4-mesh screen to remove larger corn endosperm particles, and then further screened by using an 8-mesh screen to obtain relatively uniform corn grits particles, and the pass rate under the 4-mesh screen is controlled to be 95-100%, and the retention rate on the 8-mesh screen is controlled to be 95-100%.

6. The preparation method according to claim 2, characterized in that: In the step S4, the frequency of the roller mill is set to 25-50 Hz, and the number of grinding times is 1-5 times.

7. The preparation method according to claim 1, characterized in that: In step (2), the amount of dry yeast added is 1% of the mass of the compound corn flour, the amount of water added is 45-48% of the mass of the compound corn flour, and the kneading time of the dough mixer is 5-8 minutes.

8. The preparation method according to claim 1, characterized in that: In the step (3), the first proofing time of the composite corn flour dough is 8-10 minutes.

9. The preparation method according to claim 1, characterized in that: In the step (4), the composite corn flour dough is rolled 8-10 times.

10. The preparation method according to claim 1, characterized in that: In the step (5), the raw corn steamed bun embryos are placed in a pot with cold water and steamed for 15-20 minutes.

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