Sticky steamed bun with bean paste and preparation method thereof

Abstract

The invention relates to a sticky steamed bun and a preparation method thereof, and belongs to the technical field of food processing.The preparation method comprises the following steps that 1, corn grits and polished glutinous rice are soaked, drained and ground into slurry, and slurry is obtained; (2) fermenting the slurry and a fermentation strain in a sectional type temperature control oxygenation closed spiral rice moistening fermentation pipeline to obtain fermented dough; (3) peeling the small red beans to prepare sweetened bean paste stuffing; and (4) wrapping and shaping, secondary fermentation, steaming and cooling to obtain the sticky steamed bun. In the preparation method provided by the invention, the fermentation time of the sticky steamed bun dough is short, and the production efficiency is relatively high; a large amount of domestic water can be saved, and environmental protection pressure is reduced; and the industrial production can be realized, the loss rate of the raw materials can be reduced, and the quality control of the obtained product is better.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a sticky bean curd and a preparation method thereof. Background Art

[0002] The method of making sticky bean buns mainly includes fermenting the dough skin raw materials, using red beans to make bean paste fillings, and then using the dough skin to wrap the fillings into shapes and steam them. The current sticky bean buns have large viscosity fluctuations due to material mixing problems, and when the raw materials are corn grits and glutinous rice, the fermentation efficiency of corn grits and glutinous rice is low and it is easy to be insufficiently fermented. The quality control of the production process is difficult, the standardization degree is low, the product uniformity is poor, and the flavor substances are uneven, making it difficult to industrialize production. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a sticky bean curd and a preparation method thereof.

[0004] In a first aspect, the present invention provides a method for preparing sticky rice dumplings, the method comprising the following steps: (1) Soaking, draining and grinding corn grits and glutinous rice to obtain slurry; (2) the slurry and the fermentation bacteria are fermented in a segmented temperature-controlled oxygen-filled closed spiral rice-moistening fermentation pipeline to obtain fermented dough; (3) Peeling red beans to prepare red bean paste filling; (4) forming the dumplings, performing secondary proofing, steaming, and cooling to obtain the sticky bean dumplings.

[0005] As a preferred technical solution of the present invention, the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline includes a closed fermentation pipeline, a feed port and a discharge port respectively located at both ends of the closed fermentation pipeline, and a screw located inside the closed fermentation pipeline, wherein the screw has propeller blades.

[0006] It also includes an oxygenating device, which can maintain a continuous supply of oxygen in the closed fermentation pipeline.

[0007] It also includes a temperature control interlayer, which is arranged outside the closed fermentation pipeline.

[0008] As a preferred technical solution of the present invention, in the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline, the fermentation is carried out in three stages, the temperature of the first stage is 30-32°C, the time is 3-4 h, the temperature of the second stage is 34-36°C, the time is 2-2.5 h, and the temperature of the third stage is 39-41°C, the time is 1-1.5 h.

[0009] During the fermentation process, the oxygen supply device continuously provides oxygen for the fermentation process, and the oxygen supply amount is to maintain the air pressure of the closed fermentation pipeline at 0.2-0.4 MPa.

[0010] During the fermentation process, the oxygen supply pressure error is ≤0.02 MPa.

[0011] As a preferred technical solution of the present invention, step (1) is specifically: corn grits with a particle size of 1-2 mm and glutinous rice are mixed in a mass ratio of 2:3, and soaked in water twice as much as the mass at 25-30°C for 8-12 h, and then drained and dehydrated to a moisture content of ≤25% and then ground. The particle size of the slurry after grinding is ≤100 μm, and the solid content is 35-40%.

[0012] As a preferred technical solution of the present invention, the fermentation bacteria in step (2) is Candida albicans or Tausonia pullulans, and the amount of the fermentation bacteria is 0.5-1% of the total mass of the corn grits and glutinous rice.

[0013] As a preferred technical solution of the present invention, step (3) is specifically: boiling red beans and water in a mass ratio of 1:3, simmering at 90±0.5℃ for 1.5-2 h, peeling and passing through a 60-mesh sieve, and then adding sugar and oil for frying until the moisture content is ≤30%.

[0014] As a preferred technical solution of the present invention, the wrapping and shaping in step (4) specifically comprises: cutting the fermented dough and the red bean paste filling separately, and then wrapping and shaping.

[0015] The temperature of the secondary proofing is 30±0.5°C and the time is 15 min.

[0016] As a preferred technical solution of the present invention, the steaming temperature in step (4) is to maintain the core temperature ≥ 92°C for 15 min, and the cooling is to cool to room temperature within 30 min.

[0017] As a preferred technical solution of the present invention, the preparation method further comprises quick-freezing and packaging the cooled sticky bean buns.

[0018] In a second aspect, the present disclosure provides sticky bean curd prepared by the preparation method described in the first aspect.

[0019] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art: (1) In the preparation method provided by the present invention, the fermentation time of the sticky bean bun dough is short and the production efficiency is high; (2) The preparation method provided by the present invention can save a large amount of domestic water and reduce environmental pressure; (3) The preparation method provided by the present invention can realize industrial production, which can not only reduce the loss rate of raw materials, but also improve the quality control of the obtained products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 This is a schematic diagram of the structure of a segmented temperature-controlled oxygen-filled closed spiral rice-moistening and fermentation pipeline according to an embodiment of the present invention; Among them, 1-closed fermentation pipeline; 2-feed port; 3-discharge port; 4-screw; 5-oxygenation port; 6-temperature control interlayer. DETAILED DESCRIPTION

[0023] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0025] In a first aspect, the present invention provides a method for preparing sticky rice dumplings, the method comprising the following steps: (1) Soaking, draining and grinding corn grits and glutinous rice to obtain slurry; (2) the slurry and the fermentation bacteria are fermented in a segmented temperature-controlled oxygen-filled closed spiral rice-moistening fermentation pipeline to obtain fermented dough; (3) Peeling red beans to prepare red bean paste filling; (4) forming the dumplings, performing secondary proofing, steaming, and cooling to obtain the sticky bean dumplings.

[0026] As a preferred technical solution of the present invention, Figure 1As shown, the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline includes a closed fermentation pipeline 1, a feed port 2 and a discharge port 3 respectively located at two ends of the closed fermentation pipeline, and a screw 4 located inside the closed fermentation pipeline, wherein the screw 4 is a screw with propeller blades.

[0027] The system further comprises an oxygenating device (not shown in the figure), which supplies oxygen into the closed fermentation pipeline 1 through an oxygenating port 5 , and can maintain oxygen stability in the closed fermentation pipeline 1 .

[0028] It also includes a temperature control interlayer 6, which is arranged outside the closed fermentation pipe 1. The temperature control interlayer 6 can control the temperature of the closed fermentation pipe 1 to achieve dough fermentation at different temperatures.

[0029] As a preferred technical solution of the present invention, in the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline, the fermentation is carried out in three stages, the temperature of the first stage fermentation is 30-32°C, for example, 30.5°C, 31°C, 31.5°C, etc., and the time is 3-4 h, for example, 3.2 h, 3.4 h, 3.5 h, 3.6 h, 3.8 h, etc., the temperature of the second stage fermentation is 34-36°C, for example, 34.5°C, 35°C, 35.5°C, etc., and the time is 2-2.5 h, for example, 2.1 h, 2.2 h, 2.3 h, 2.4 h, etc., the temperature of the third stage fermentation is 39-41°C, for example, 39.5°C, 40°C, 40.5°C, etc., and the time is 1-1.5 h, for example, 1.1 h, 1.2 h, 1.3 h, 1.4 h, etc.

[0030] During the fermentation process, the oxygenation device continuously provides oxygen for the fermentation process, and the oxygen supply amount is to maintain the air pressure of the closed fermentation pipeline 1 at 0.2-0.4 MPa, for example, 0.22 MPa, 0.25 MPa, 0.28 MPa, 0.30 MPa, 0.32 MPa, 0.35 MPa, 0.38 MPa, etc.

[0031] During the fermentation process, the oxygen supply pressure error is ≤0.02 MPa, such as 0.02 MPa, 0.01 MPa, etc.

[0032] As a preferred technical solution of the present invention, the diameter of the closed fermentation pipeline 1 can be 500 mm.

[0033] The segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline provided by the present invention can promote the full mixing of corn grits and glutinous rice, and the segmented temperature control can enable the fermented dough to be fermented at different fermentation temperatures in different time periods, so that the fermented dough provided by the present invention can complete the fermentation in about 6-8 hours. Compared with the traditional fermentation method that takes a longer time to complete the fermentation, the method provided by the present invention has high fermentation efficiency and can greatly shorten the fermentation time.

[0034] Moreover, the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline provided by the present invention can be easily oxygenated, maintain oxygen stability, and is easy to clean. At the same time, since it is in a closed state during the fermentation process, the fermentation method provided by the present invention can effectively prevent contamination by miscellaneous bacteria, effectively prevent pathogenic bacteria and conditional pathogenic bacteria from contaminating raw materials, and reduce the raw material loss rate by about 15%, that is, the quality control of the method provided by the present invention is relatively simple. The fermentation method provided by the present invention can save about 80% of production water and can also reduce environmental pressure.

[0035] At the same time, the fermentation method provided by the present invention is mechanized fermentation, the quality of the obtained fermented dough is good and the quality control is uniform, and the qualified rate of the sticky bean buns prepared by the preparation method provided by the present invention can reach more than 98%.

[0036] As a preferred technical solution of the present invention, step (1) is specifically as follows: corn grits with a particle size of 1-2 mm and glutinous rice are mixed in a mass ratio of 2:3, and soaked at 25-30°C for 8-12 hours with 2 times the mass of water, and then drained and dehydrated to a water content of ≤25% and then ground. The particle size of the slurry after grinding is ≤100 μm, and the solid content is 35-40%. In the present invention, the proportion of glutinous rice ≥60% can ensure the stickiness and taste of the sticky bean buns. If the corn grits content is too high, the stickiness is insufficient and the taste is relatively rough.

[0037] In the present invention, the particle size of 1-2 mm can be 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, etc., the 25-30℃ can be 25.5℃, 26℃, 26.5℃, 27℃, 27.5℃, 28℃, 28.5℃, 29℃, 29.5℃, etc., the 8-12 h can be 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, etc., the water content ≤25% can be 24%, 23%, 22%, 21%, 20%, 18%, etc., the particle size ≤100 μm can be 90 μm, 80 μm, etc., and the solid content 35-40% can be 36%, 37%, 38%, 39%, etc.

[0038] As a preferred technical solution of the present invention, the impurities in the corn residue and glutinous rice are both ≤0.1%.

[0039] In the present invention, it is recommended to use natural wild fungus species for industrial production, which have high stability. As a preferred technical solution of the present invention, the fermentation bacteria in step (2) is Candida albicans or Tausonia pullulans, and the amount of the fermentation bacteria is 0.5-1% of the total mass of the corn grits and glutinous rice, for example, 0.6%, 0.7%, 0.8%, 0.9%, etc.

[0040] As a preferred technical solution of the present invention, step (3) is specifically as follows: boil red beans and water in a mass ratio of 1:3, simmer at 90±0.5℃ for 1.5-2 h, such as 1.6 h, 1.7 h, 1.8 h, 1.9 h, etc., peel and sieve through a 60-mesh sieve, and then add sugar and oil for frying until the moisture content is ≤30%, such as 29%, 28%, 27%, 25%, 22%, etc. In the present invention, the moisture content of the bean paste filling is ≤30% to prevent bursting during the steaming process. In the present invention, the moldy rate of the red beans is ≤0.5%.

[0041] As a preferred technical solution of the present invention, the wrapping and shaping in step (4) specifically comprises: cutting the fermented dough and the red bean paste filling separately, and then wrapping and shaping.

[0042] The temperature of the secondary proofing is 30±0.5°C and the time is 15 min.

[0043] As a preferred technical solution of the present invention, the steaming temperature in step (4) is to maintain the core temperature ≥ 92°C for 15 minutes, and the cooling is to cool to room temperature within 30 minutes. In the present invention, the core temperature ≥ 92°C can play a role in sterilization and shaping.

[0044] As a preferred technical solution of the present invention, during steaming, the steaming plate can be brushed with oil or padded with corn leaves or silicone pads for anti-sticking treatment.

[0045] As a preferred technical solution of the present invention, the preparation method further comprises quick-freezing and packaging the cooled sticky bean buns.

[0046] As a preferred technical solution of the present invention, the quick freezing is quick freezing at -30°C for 30 min, and the core temperature is ≤-18°C. In the present invention, the efficiency of quick freezing is passing through the maximum ice crystal formation zone (-1~-5°C) within 30 min.

[0047] As a preferred technical solution of the present invention, the packaging can be 6-8 pieces / bag, and can be vacuum packed or nitrogen packed.

[0048] The preparation method of the sticky bean buns provided by the invention can save a large amount of domestic water and reduce environmental pressure, and at the same time, the fermentation time of the sticky bean buns dough is short and industrial production can be realized, so that the obtained product has better quality control and higher production efficiency.

[0049] In a second aspect, the present disclosure provides sticky bean curd prepared by the preparation method described in the first aspect.

[0050] The sticky bean curd provided by the invention has increased flavor substances, a high quality uniformity rate of more than 98%, and a long shelf life. The quick-frozen product can be stored for 12 months at -18°C, stored for 7 days in a refrigerator (0-4°C), and the shelf life at room temperature can be extended by 3 days.

[0051] The following is an explanation through specific embodiments.

[0052] If no specific techniques or conditions are specified in the examples, the conventional techniques or conditions in the art, or the techniques or conditions described in the literature, or the product instructions are used. If the raw materials or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially.

[0053] Example

[0054] This embodiment provides a method for preparing sticky bean curd and the obtained sticky bean curd, which are as follows: (1) Mix corn grits with a particle size of 1-2 mm and glutinous rice in a mass ratio of 2:3, add twice the mass of water and soak at room temperature (25-30°C) until they are easily broken by hand (8-12 h), drain and dehydrate to a moisture content of ≤25%, and then grind the slurry. The particle size of the slurry after grinding is ≤100 μm, and the solid content is adjusted to 35-40%; (2) The slurry and the fermentation bacteria are fermented in a segmented temperature-controlled oxygen-filled closed spiral rice-smoothing fermentation pipeline to obtain fermented dough, wherein the fermentation is carried out in three stages, wherein the temperature of the first stage is 31°C and the time is 3.5 h, the temperature of the second stage is 35°C and the time is 2.5 h, and the temperature of the third stage is 40°C and the time is 1 h; During the fermentation process, the oxygen supply is to maintain the air pressure of the closed fermentation pipeline at 0.2-0.4 MPa, and the oxygen supply pressure error is ≤0.02 MPa; (3) Boil red beans and water in a mass ratio of 1:3, simmer at 90±0.5℃ until soft (1.5-2h), peel with a screw extruder, pass the bean paste through a 60-mesh sieve, fry in a sandwich wok, add 50% brown sugar and 10% oil based on the mass of the red bean raw material, and fry until the beans are clumping and not sticky (water content ≤30%). (4) The fermented dough was divided into 30 g / piece and the red bean paste filling was divided into 15 g / piece. The dough was shaped using an automatic stuffing machine with the seam facing downward and the surface smooth and without cracks. The dough was then proofed for a second time at 30±0.5℃ for 15 min. (5) Steam in a tunnel steamer at 100°C for 15 min (core temperature ≥ 92°C), and then cool to room temperature within 30 min; (6) Alternatively, they can be quick-frozen at -30°C for 30 min, with the core temperature ≤ -18°C, and then vacuum-packed or nitrogen-filled, with 6-8 pieces per bag.

[0055] Comparative Example

[0056] This comparative example provides a traditional method for preparing sticky rice dumplings, which is as follows: (1) Soak red beans and water in a mass ratio of 1:3 for more than 12 hours. During the soaking process, the water needs to be changed and the container needs to be cleaned. Then, cook until soft (1.5-2 hours), peel with a screw extruder, pass the bean paste through a 60-mesh sieve, and stir-fry in a sandwich wok. Add 20% of the mass of red bean raw material brown sugar and 10% of oil, and stir-fry until the red bean can be grasped into a ball without sticking to the hand (water content ≤ 30%). (2) The yellow rice / glutinous rice flour is scalded and kneaded in 60-80℃ water, and then naturally fermented at 18-25℃ (usually for about 16 hours, and generally for about 24 hours in winter); (3) The fermented dough was divided into 30 g / piece and the red bean paste filling was divided into 15 g / piece. The dough was shaped using an automatic stuffing machine with the seam facing downward and the surface smooth and without cracks. The dough was then proofed for a second time at 30±0.5℃ for 15 min. (4) Steam in a tunnel steamer at 100°C for 15 min (core temperature ≥ 92°C), and then cool to room temperature within 30 min; (5) Alternatively, they can be quick-frozen at -30°C for 30 min, with the core temperature ≤ -18°C, and then vacuum-packed or nitrogen-filled, with 6-8 pieces per bag.

[0057] Performance Testing

[0058] The sticky bean curd provided in the embodiment and the comparative example was subjected to performance testing as follows: (1) Food safety test, test indicators include: Microbiological indicators: Total colony count, safety limit: raw product ≤ 10 5 CFU / g; cooked products ≤10 5 CFU / g.

[0059] Coliform group, safety limit value: ≤10 CFU / g.

[0060] Pathogenic bacteria: Salmonella: shall not be detected in 25 g sample; Staphylococcus aureus: ≤100 CFU / g.

[0061] Chemical pollutants Heavy metals: Lead (Pb): ≤0.5 mg / kg (GB 2762-2022).

[0062] Arsenic (As): ≤0.5 mg / kg.

[0063] additive Preservatives (such as benzoic acid): Not allowed to be added.

[0064] Mycotoxins Aflatoxin B1: ≤5 μg / kg.

[0065] Other indicators Sensory inspection: No mold or odor on the appearance, and normal texture.

[0066] (2) Product qualification rate test 1. Sensory test: Smell / taste: rinse your mouth with warm water and taste it. It should have the smell and taste of the product, without any foreign smell (slightly sour or slightly smelly due to the fermentation process is allowed); Condition: No mildew, insects or foreign matter. 2. Physical and chemical index testing Moisture: Detected using GB 5009.3 method, moisture content ≤75%.

[0067] Filling content: only applicable to sticky rice dumplings, tested according to GB / T 23780, filling content ≥ 20%.

[0068] Heavy Metals and Toxins: Lead (Pb) content <0.5 mg / kg (GB 5009.12); Aflatoxin B1 ≤ 20 μg / kg (GB 5009.22).

[0069] 3. Microbiological testing Total colony count: tested according to GB 4789.2 method, the sampling plan is n=5, c=1, m=10^4 CFU / g, M=10^5CFU / g (that is, at most 1 of 5 samples is allowed to be between 10^4 and 10^5, and the rest must be less than 10^4).

[0070] 4. Eligibility criteria and minimum limits Sensory requirements: no mold, foreign matter, normal smell and taste.

[0071] Physical and chemical indicators: Moisture ≤ 75%, filling content (only for sticky bean curd) ≥ 20%, lead < 0.5 mg / kg, aflatoxin B1 ≤ 20 μg / kg; Microbial limit: total colony count ≤10^4 (qualified standard); 5. Determination rules Qualification rate determination: According to the sampling plan (n=5), if the test results show: Total colony count: ≤1 sample is between 10^4~10^5, and the rest are ≤10^4, then it is considered qualified; Other indicators: All samples must meet the limit standards. If any item exceeds the limit, it will be judged as unqualified.

[0072] 6. Based on the standards: THACDB 001-2022: Applicable to the physical, chemical and microbiological testing of sticky bean buns and sticky cakes; GB 5009 series: For specific testing methods, refer to the corresponding national standards.

[0073] (3) Shelf life test 1. Microbiological stability test Testing cycle: Sampling shall be carried out according to GB 4789.1, and microbial indicators (total colony count, coliform group, mold, pathogenic bacteria) shall be tested regularly (such as 0 days, 7 days, 15 days, 30 days, etc.); Storage conditions: simulate actual storage environment (such as room temperature, refrigeration or freezing) and record changes in temperature and humidity; Judgment basis: When the microbial index exceeds (total colony count> 10 5 CFU / g, coliform group>10² CFU / g, mold>50 CFU / g) or (pathogenic bacteria detection) limit, it is judged as spoiled.

[0074] 2. Physical and chemical index testing: Moisture content: Tested according to GB 5009.3, ensure that the moisture content during storage is ≤75% (to prevent mildew).

[0075] Heavy metals and toxins: Regularly test lead (Pb < 0.5 mg / kg) and aflatoxin B1 (≤ 20 μg / kg) to prevent exceeding the standard.

[0076] 3. Sensory evaluation Color, smell, texture: According to the sensory requirements of standard T / HACDB 001-2022, observe whether there is mold, odor, foreign matter or rancidity. If so, it means it is spoiled.

[0077] (4) Raw material loss rate Weigh the total raw material input, record the raw material loss in each link and weigh the finished product at last. The raw material loss is total loss / total input.

[0078] The test results are as follows: (1) Food safety: After testing, the total colony count, Escherichia coli group, pathogenic bacteria, chemical pollutants, etc. of the sticky bean curd prepared by the method provided by the present invention all meet the food safety regulations, that is, the sticky bean curd provided by the present invention meets the food safety standards.

[0079] (2) Product qualification rate test: From the performance test, it can be seen that the qualification rate of the comparative example is only 77%, and contamination by Salmonella, Staphylococcus aureus, Bacillus cereus, Clostridium perfringens and the like often occurs. However, the sticky bean curd obtained by the preparation method provided by the present invention has basically no risk of contamination by the above pathogenic bacteria, and the product qualification rate can reach more than 98%. That is, the preparation method provided by the present invention can improve the uniformity of product quality by more than 20%.

[0080] (3) Shelf life test: The performance test shows that the shelf life of the sticky rice dumplings of the comparative example at room temperature is only 3 days, while the shelf life of the sticky rice dumplings prepared by the preparation method provided by the present invention at room temperature is 5 days, which is extended by 2 days. That is, the sticky rice dumplings of the present invention have a longer shelf life.

[0081] (4) Raw material loss rate: Performance testing shows that the raw material loss rate of the preparation method provided by the present invention is reduced by about 15%.

[0082] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0083] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing sticky rice dumplings, characterized in that: The preparation method comprises the following steps: (1) Soaking, draining and grinding corn grits and glutinous rice to obtain slurry; (2) the slurry and the fermentation bacteria are fermented in a segmented temperature-controlled oxygen-filled closed spiral rice-moistening fermentation pipeline to obtain a fermented dough; (3) Peeling red beans to prepare red bean paste filling; (4) forming the dumplings, performing secondary proofing, steaming, and cooling to obtain the sticky bean dumplings.

2. The preparation method according to claim 1, characterized in that: The segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline comprises a closed fermentation pipeline, a feed port and a discharge port respectively located at two ends of the closed fermentation pipeline, and a screw located inside the closed fermentation pipeline, wherein the screw has a propeller blade; Also included is an oxygenating device, which can maintain a continuous supply of oxygen in the closed fermentation pipeline; It also includes a temperature control interlayer, which is arranged outside the closed fermentation pipeline.

3. The preparation method according to claim 2, characterized in that: In the segmented temperature-controlled oxygenated closed spiral rice-moistening fermentation pipeline, the fermentation is carried out in three stages, the first stage is fermented at a temperature of 30-32° C. for 3-4 h, the second stage is fermented at a temperature of 34-36° C. for 2-2.5 h, and the third stage is fermented at a temperature of 39-41° C. for 1-1.5 h. During the fermentation process, the oxygen supply device continuously provides oxygen for the fermentation process, and the oxygen supply amount is to maintain the air pressure of the closed fermentation pipeline at 0.2-0.4 MPa; During the fermentation process, the oxygen supply pressure error is ≤0.02 MPa.

4. The preparation method according to claim 1, characterized in that: Step (1) is specifically as follows: corn grits with a particle size of 1-2 mm and glutinous rice are mixed in a mass ratio of 2:3, and soaked in water twice as much as the mass thereof at 25-30° C. for 8-12 h, and then drained and dehydrated to a moisture content of ≤25%, and then ground. The particle size of the slurry after grinding is ≤100 μm, and the solid content is 35-40%.

5. The preparation method according to claim 1, characterized in that: In step (2), the fermentation strain is Candida albicans or Tausonia pullulans, and the amount of the fermentation strain is 0.5-1% of the total mass of the corn grits and glutinous rice.

6. The preparation method according to claim 1, characterized in that: Step (3) is specifically as follows: boil red beans and water in a mass ratio of 1:3, simmer at 90±0.5℃ for 1.5-2 h, peel and sieve through a 60-mesh sieve, and then add sugar and oil to stir-fry until the moisture content is ≤30%.

7. The preparation method according to claim 1, characterized in that: The wrapping and shaping in step (4) specifically comprises: cutting the fermented dough and the red bean paste filling separately, and then wrapping and shaping; The temperature of the secondary proofing is 30±0.5°C and the time is 15 min.

8. The preparation method according to claim 1, characterized in that: The steaming temperature in step (4) is to maintain the center temperature ≥ 92°C for 15 min, and the cooling is to cool to room temperature within 30 min.

9. The preparation method according to claim 1, characterized in that: The preparation method further comprises quick freezing and packaging the cooled sticky bean curd buns.

10. The sticky rice dumplings prepared by the preparation method according to any one of claims 1 to 9.

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