39results about How to "Increase specific volume" patented technology

The present invention discloses an engineered Trichoderma reesei for producing lipase, and a construction method and application thereof, and belongs to the fields of molecular biology and biotechnology. The engineered Trichoderma reesei heterologously expresses a lipase having an amino acid sequence as shown in SEQ ID NO.1; in the engineered Trichoderma reesei, the genes of the original cellulases cbh1 and cbh2 and xylanases xyn1 and xyn2 in Trichoderma reesei are replaced in sequence with genes encoding the lipase; the nucleotide sequence of the gene encoding the lipase is shown in SEQ ID NO.2. The present invention successfully constructs an engineered Trichoderma reesei strain that secretes and expresses lipase. The engineered strain can be used for the production of food-grade lipase, and the produced lipase meets food safety standards, and can significantly improve the specific volume and whiteness of baked goods (such as bread), which will be more suitable for actual food industry needs.

The invention relates to the technical field of aluminum electrolytic capacitors, in particular to a preparation method of a high-strength sintered foil for an aluminum electrolytic capacitor. The preparation method of the high-strength sintered foil for the aluminum electrolytic capacitor comprises the following steps: 1, uniformly mixing modified carbon quantum dot powder and aluminum powder, adding a solvent, and uniformly stirring to obtain modified aluminum powder slurry; 2, further adding a binder and an additive, and uniformly stirring to obtain mixed slurry; 3, uniformly coating the slurry on the surface of an aluminum foil substrate and curing; 3, sintering the obtained aluminum foil substrate; and 4, forming the sintered foil to obtain the anode powder sintered foil. Compared with the prior art, the high-strength sintered foil for the aluminum electrolytic capacitor has the advantages that high capacity and mechanical strength are guaranteed, carbon residues are avoided, and the dielectric property of the sintered foil is improved.

The invention provides a preparation method of a special aluminum electrolytic capacitor for a low-temperature-resistant detonator trigger, and the method comprises the following steps: cutting a positive electrode foil and a negative electrode foil, and riveting the cut positive electrode foil and negative electrode foil with a positive guide pin and a negative guide pin; placing electrolytic paper between the riveted positive electrode foil and negative electrode foil, winding the electrolytic paper to form a core package, injecting electrolyte into the core package, and sealing the core package in an aluminum shell by using colloidal particles to obtain a semi-finished capacitor; and cleaning the semi-finished product capacitor, sleeving, and sequentially carrying out primary aging sorting, secondary aging sorting, appearance observation and inspection to obtain the capacitor. The preparation method of the aluminum electrolytic capacitor special for the low-temperature-resistant detonator trigger is simple in production process, common in material and low in price, and the prepared aluminum electrolytic capacitor is excellent in electrical performance, wide in working temperature range and small in size.

The invention belongs to the technical field of electrode materials, and particularly relates to an electrode foil, a preparation method thereof and an aluminum electrolytic capacitor, and the preparation method of the electrode foil comprises the steps: carrying out the formation of a corrosion foil, and forming an aluminum oxide film on the surface of the corrosion foil; forming a nano-porous silicon dioxide film on the surface of the aluminum oxide film to obtain an electrode foil with an aluminum oxide-silicon dioxide double-layer composite oxide film; and sequentially carrying out phosphating treatment and annealing treatment on the electrode foil. According to the preparation method, after the corrosion foil is subjected to formation treatment to form the Al2O3 film, the nano-porous SiO2 film is formed on the surface of the Al2O3 film, the SiO2 film is subjected to phosphating treatment to contain phosphorus elements, the phosphorus elements are uniformly diffused into the SiO2 film, a double-layer composite oxidation film with the Al2O3 inner layer and the SiO2 outer layer is obtained, and the specific volume, the hydration resistance and the corrosion resistance of the low-voltage electrode foil are improved.

The invention belongs to the technical field of formed foils, and particularly relates to application of a treating fluid as an additive for improving the bending resistance of a formed foil and a preparation method of the bending-resistant formed foil. The treating fluid comprises a water-soluble polymer material, and the water-soluble polymer material is selected from one or more of polyethylene glycol, polyvinyl alcohol, hydroxypropyl methyl cellulose or polyethylene glycol borate; the mass concentration of the water-soluble polymer material in the treating fluid is 0.1-0.7%. The treating fluid can greatly improve the bending resistance of the formed foil and maintain the high specific volume of the formed foil.

The invention discloses a production method for anodizing, chambering and corroding an electrode foil, belongs to the technical field of electrode foils, and adopts ultrasonic waves to generate a cavitation effect in liquid, promote a corrosion process and improve uniform hole forming and performance of an aluminum foil. A domestic plain aluminum foil of 132 microns is used, and proper holes are obtained through three-stage treatment of alkali washing, hole-forming corrosion and chambering corrosion and hole-forming corrosion of a mixed solution composed of sulfuric acid and hydrochloric acid. The polyethyleneimine is added into a reaming phosphoric acid solution to slow down corrosion, aluminum foil holes subjected to three-stage treatment contain Cl <->, metal impurities, phosphoric acid and the like, corrosion is caused to products, and the quality of oxidation films is reduced. Impurities are cleaned through dilute nitric acid, a compact and firm oxidation film is obtained, then sol-gel coating and subsequent formation treatment are carried out, the anode formation chambering corrosion electrode foil is obtained, and the specific capacitance of the foil is effectively improved.

The invention discloses corrosion aluminum powder and a preparation method and application thereof, and the preparation method comprises the following steps: S1, carrying out plasma passivation treatment on aluminum powder to obtain surface modified aluminum powder with an amorphous aluminum oxide layer; and S2, carrying out surface micro-corrosion on the surface modified aluminum powder, and then drying and grading to obtain the corroded aluminum powder. The method comprises the following steps: forming an amorphous aluminum oxide layer on the surface of aluminum powder; and then micro-corrosion is carried out on the amorphous aluminum oxide layer, a rich pore structure is formed on the amorphous aluminum oxide layer, and after corrosion is completed, the amorphous aluminum oxide layer can be automatically formed on the corrosion surface again. The surface of the obtained corrosion aluminum powder is completely wrapped by the amorphous aluminum oxide layer, so that the leakage current can be greatly reduced, and the electrochemical stability of the anode foil is greatly improved; the porous carbon has certain roughness and rich pore structures, and the specific surface area and the specific volume are greatly increased; the micro-corrosion has no negative influence on the mechanical strength of the aluminum powder, and ensures that no micro-crack appears on the surface of the anode foil.

The invention relates to the field of food processing, and particularly discloses a bread fermentation accelerant and application thereof in bread baking. The bread fermentation accelerant comprises isomaltooligosacharide, galactooligosaccharide and fructo-oligosaccharide in a mass ratio of 5: (2-4): (1-2). The bread fermentation accelerant has the advantages that the bread fermentation accelerant can be used for bread with the high dietary fiber content, the fermentation capacity of the bread with the high dietary fiber content is improved, the specific volume of the bread is increased, and the bread is full and complete in appearance, soft and elastic in texture, spongy in tissue, uniform in air hole, good in ductility, golden in color and luster, fragrant, soft and delicious.

The invention discloses a preparation method and application of an edible skin protective agent for frozen green dough, and belongs to the technical field of food. The edible epidermis protective agent comprises the following components: acetylated distarch adipate, carboxymethyl cellulose, ascorbic acid, glycerol and water. The invention further discloses application of the skin protective agent in frozen green bodies, namely, the skin protective agent is prepared into a coating to be applied to frozen green body dough, and the frozen green body dough coated with the protective agent can keep good specific volume, height-diameter ratio, apparent color and texture quality after being subjected to freezing and thawing cycles. Meanwhile, the protective agent can also relieve dough skin damage caused by recrystallization and moisture migration of ice crystals and damage of a gluten protein network and starch particles in the freezing and thawing cycle process. The method is beneficial to improving the quality of the frozen green flour product, prolonging the preservation time and promoting the standardized and industrial production of the frozen green flour product.

The invention belongs to the technical field of positive electrode materials, and particularly relates to a composite-phase ternary positive electrode material and a preparation method and application thereof. The preparation method of the composite-phase ternary positive electrode material comprises the following steps: S1, mixing a ternary positive electrode material precursor with a first lithium source, and sintering to obtain a first sintered product; s2, mixing the primary sintered product, a sodium source and a cobalt source, and calcining to obtain a secondary sintered product; and S3, mixing the secondary burning product with a second lithium source, and carrying out ion exchange reaction to obtain the composite-phase ternary positive electrode material, the battery containing the composite-phase ternary positive electrode material prepared by the invention has excellent specific capacity, coulombic efficiency and cycle performance.

The invention discloses a method for preparing corn steamed buns through lactobacillus plantarum and yeast fermentation, belongs to the technical field of food processing, and adopts the synergistic effect of lactobacillus plantarum JSLp-20 and saccharomycetes to shorten the fermentation time of high-proportion corn steamed buns; organic acid is generated through synergistic fermentation, starch acid hydrolysis is promoted, meanwhile, esterification reaction with alcohols is carried out to generate flavor substances such as esters, the flavor of the steamed buns is enriched, and the ageing resistance and the water binding capacity of the starch are improved; the specific volume of the prepared corn steamed bun is increased by 18.75%, the hardness, the cohesiveness and the chewiness are reduced by 3.60%, 4.00% and 5.19% respectively, the elasticity and the adhesiveness are increased by 1.14% and 57.36% respectively, the resilience is increased by one time, the total score of sensory evaluation is remarkably increased, and the prepared corn steamed bun product does not collapse or crack and has considerable texture properties.

The application discloses an application of myrtenal in preparation of an anti-leukemia drug and belongs to the technical field of drug application. A structural formula of the myrtenal is shown in the following. The myrtenal (WRT-4) has a significant proliferation inhibition and pro-apoptosis effect on leukemia cells HEL through in-vitro experiments, and the effect is in a concentration-dependent manner; the mechanism is that the WRT-4 can down-regulate the expression of anti-apoptotic proteins Bcl-2 and Bcl-xl, up-regulate the expression of pro-apoptotic protein BID, and then activate Caspase 9 and Caspase 3 to induce leukemia cell apoptosis. In-vivo pharmacodynamic experiments show that the WRT-4 can significantly reduce the volume and weight of spleens of erythroleukemia model mice, improve the hematocrit and effectively improve the spleen tissue structure. The application provides a new active substance source for research and development of anti-leukemia drugs.

The present invention discloses an electrode material of a biomass-derived carbon composite transition metal sulfide solid solution, comprising a biomass-derived carbon skeleton with a three-dimensional network hollow tubular structure and transition metal sulfide solid solution nanoparticles loaded on the carbon skeleton; the electrode material has a chemical composition represented by ABX@BDC, wherein A and B are independently selected from one of transition metal elements Fe, Co, Ni, Cu, Mn, Zn and Sn, X is a non-metallic element S or Se, and BDC is a biomass-derived carbon skeleton. The electrode material prepared by the present invention has high specific capacity, excellent cycle stability and rate performance. And it has attractive reversible capacity, ultra-long cycle life and good structural stability at ultra-high rate. The raw material resources are abundant, the cost is low, the preparation process is simple, the time consumption is short, the reaction conditions are also very easy to achieve, and it can be mass-produced, convenient for commercial application, and shows great application prospects in sodium ion batteries.

The present invention belongs to the field of electrochemical energy storage technology, and specifically relates to a potassium metal capacitor and a preparation method thereof. The capacitor of the present invention includes a potassium metal negative electrode, a positive electrode with a carbon material or a carbon-based composite material as an active material, and an organic solvent electrolyte dissolved with a potassium salt. Compared with traditional potassium ion capacitors, the preparation process and cost of the device are greatly simplified, and its fast electrochemical reaction kinetics can achieve a good match with the capacitive positive electrode material. Therefore, the potassium metal capacitor assembled by the metal potassium negative electrode and the capacitive carbon positive electrode of the present invention has an energy density close to that of a traditional potassium ion battery, and at the same time can achieve the characteristics of high power density of the capacitor, and can be used in large-scale energy storage systems with high energy and high power density requirements.

The present invention relates to the technical field of manufacturing electrode foil for aluminum electrolytic capacitors, and specifically to a method for preparing electrode foil for low-defect and high-capacity aluminum electrolytic capacitors. The method for preparing electrode foil for low-defect and high-capacity aluminum electrolytic capacitors of the present invention comprises the following steps: (1) pickling, (2) first pulse treatment, (3) chemical formation treatment, (4) heat treatment, (5) second pulse cleaning, (6) chemical formation repair treatment, and (7) passivation. The electrode foil for low-defect and high-capacity aluminum electrolytic capacitors of the present invention removes the hydrated aluminum oxide film generated on the surface of the corroded foil in the air and the hydrated aluminum oxide film produced in the chemical formation process by pulse laser cleaning, and performs oxide film repair in a chemical formation repair solution, thereby promoting the formation of a high-crystallinity anodized film, reducing defects, and improving density.

The invention provides sour dough, a sour dough steamed bun and a preparation method and application thereof, and belongs to the technical field of food manufacturing. The sour dough provided by the invention is prepared from 500 parts of wheat flour, 0.05-0.2 part of lactobacillus reuteri and 260 parts of water, and the preparation method of the sour dough comprises the following steps: mixing the wheat flour, the lactobacillus reuteri and the water according to the formula ratio, kneading to form dough, and fermenting for 6.5-10 hours under the conditions that the temperature is 33-40 DEG C and the humidity is 80%-95% to obtain the sour dough. Compared with steamed buns prepared by traditional methods and steamed buns prepared by other kinds of sour dough, the sour dough steamed buns prepared by the sour dough provided by the invention have the advantages that the specific volume is larger, the content of rapidly digestible starch is higher, the speed of hydrolyzing glucose is higher, and the sour dough steamed buns have the effect of rapidly providing energy for human bodies.

This invention belongs to the field of electrode material technology, specifically relating to an anode foil, its preparation method, and an aluminum electrolytic capacitor. The preparation method of the anode foil includes performing a secondary porosimetry etching on the aluminum foil after primary porosimetry etching. The secondary porosimetry etching includes multiple stages of porosimetry etching, with a mid-treatment process between each adjacent stage. This preparation method involves multiple stages of porosimetry etching, and the mid-treatment process between each adjacent stage effectively increases the pore size of the etched foil, making it suitable for preparing ultra-high voltage anode foils with low loss and high specific capacitance.

The invention discloses a hollow tire-shaped carbon material composite transition metal sulfur selenide electrode material, which comprises a carbon skeleton and a transition metal sulfur selenide nanosheet material, the carbon skeleton is derived from aspergillus niger spores and has a three-dimensional hollow tire-shaped structure, the transition metal sulfur selenide nanosheet material is loaded on the carbon skeleton, and the outer layer of the nanosheet material is coated with a carbon layer; the electrode material has a chemical composition represented by ANDC (at) MSSe (at) C, ANDC is a hollow tire-shaped carbon skeleton derived from Aspergillus niger, and M is a metal element Sn, Mo or W. The electrode material disclosed by the invention has relatively high specific capacity, still has good retention performance under 2000 cycles, shows relatively good electrochemical performance with stable cycle, and still has very good structural stability and long cycle life under an ultrahigh rate. The preparation method is low in raw material cost and low in energy consumption, reaction conditions are easier to realize, commercial application is facilitated, and the preparation method has a huge application prospect in sodium ion batteries.

The invention belongs to the technical field of industrial production, and provides a wide-load long-transmission steam pipe network system and an operation method thereof. A steam turbine generator unit is connected with a main pipe through a rated parameter steam extraction pipe and a high parameter steam extraction pipe which are connected in parallel; a steam source in a rated parameter steam extraction pipe and a steam source in a high parameter steam extraction pipe are mixed to obtain a steam source higher than rated parameters, especially pressure, so that the specific volume of steam is reduced, if the flow speed in a pipe network is kept unchanged, a large pipe diameter is not needed, the pipe diameters of a main pipe and a branch pipe can be reduced, and through pipe diameter optimization, the cost is reduced. Compared with the prior art, construction investment cost of a pipe network is effectively reduced, along with reduction of the pipe diameter, under the same heat preservation condition, the overall heat dissipation area of the pipeline is reduced, heat dissipation of the pipeline is reduced under low load, temperature drop is smaller, the requirement for lower flow load can be met, along with reduction of the pipe diameter, materials used by the pipeline are reduced, and due to reduction of the surface area, cost is reduced. The requirement for heat preservation is lowered, and the temperature of steam received by a user side can be guaranteed.

The invention discloses a gluten-free Chinese chestnut steamed bun composite modifier and application thereof, and belongs to the technical field of food additives. The gluten-free Chinese chestnut steamed bun composite modifier is prepared by mixing whey protein, alpha-amylase, xanthan gum and monoglyceride, wherein the weight part ratio of the whey protein to the alpha-amylase to the xanthan gum to the monoglyceride is (15-25): (0.3-0.45): (1-2): (0.2-0.4). The gluten-free Chinese chestnut steamed bun composite modifier is used for improving the hardness, elasticity, chewiness, sensory quality and specific volume of steamed bun, and solves the problems of poor gas-holding property and difficult forming of gluten-free Chinese chestnut steamed bun.

The present invention relates to the technical field of aluminum electrolytic capacitors, and specifically to a method for preparing a high-strength sintered foil for aluminum electrolytic capacitors. The method for preparing a high-strength sintered foil for aluminum electrolytic capacitors of the present invention comprises the following steps: 1. Evenly mix modified carbon quantum dot powder and aluminum powder, and add a solvent and stir evenly to obtain a modified aluminum powder slurry; 2. Further add a binder and an additive and stir evenly to obtain a mixed slurry; 3. Evenly coat the slurry on the surface of an aluminum foil substrate and solidify it; 3. Sinter the obtained aluminum foil substrate; 4. Chemically form the sintered foil to obtain an anode powder sintered foil. Compared with the prior art, the high-strength sintered foil for aluminum electrolytic capacitors of the present invention avoids carbon residue while ensuring higher capacity and mechanical strength, thereby improving the dielectric properties of the sintered foil.

The utility model discloses a tantalum capacitor shell packaging structure that improves mechanical strength relates to tantalum capacitor shell packaging technical field, including outer layer packaging shell and middle layer packaging shell, the inside of outer layer packaging shell is provided with middle layer packaging shell, and the inside of middle layer packaging shell is provided with inner layer packaging shell, and the top surface of outer layer packaging shell is provided with first reinforcing rib, and the left and right sides of outer layer packaging shell all are provided with second reinforcing rib. This tantalum capacitor shell packaging structure that improves mechanical strength, through being provided with the outer layer packaging shell of layer -by -layer nesting structure, middle layer packaging shell, inner layer packaging shell, utilize the cooperation of the structure between three, can provide structural protection for internal component as far as possible, to guarantee the operation stability of whole, cooperate the structural setting of base, first reinforcing rib and second reinforcing rib, can further guarantee the mechanical strength of whole packaging structure like this.

The preparation method of the sour dough steamed bun based on the liquid state fermentation method comprises the following steps: 1) mixing liquid state acid, water and wheat flour to prepare medium-sized flour paste, and fermenting the medium-sized flour paste at normal temperature; (2) mixing the sponge paste prepared in the step (1) with wheat flour and alkali to prepare main dough; and (3) cutting, tabletting, forming, fermenting and steaming the main dough prepared in the step (2) to obtain the sour dough steamed bun. Industrial production of the sour dough steamed bun is facilitated, and the taste and flavor of the sour dough steamed bun are further improved.

The invention belongs to the technical field of electrode materials, and particularly relates to an anode foil, a preparation method thereof and an aluminum electrolytic capacitor. The preparation method comprises the following steps: placing an aluminum foil in an electrolytic bath solution containing zinc ions to carry out micro-arc oxidation treatment so as to form a porous aluminum oxide film containing a zinc element on the surface of the aluminum foil; and before hole forming treatment, the aluminum foil subjected to micro-arc oxidation treatment is sequentially subjected to soaking treatment, electrolytic polishing treatment and hydration treatment. According to the preparation method provided by the invention, the anode foil with relatively good specific volume and bending performance can be obtained.

The invention discloses a method for preparing rice bread by using southern japonica rice as a raw material, which comprises the following steps of: crushing and sieving the southern japonica rice as the raw material, mixing polished round-grained rice powder and hydroxypropyl methyl cellulose (HPMC), co-extruding to obtain co-extruded powder, and mixing the polished round-grained rice powder and the co-extruded powder according to a certain mass ratio to prepare a rice bread product. The defect that the rice bread is difficult to form a stable structure due to lack of gluten (namely wheat gluten protein) is overcome, pores of the obtained rice bread product are uniform and compact, the texture and taste of the rice bread are improved, and the rice bread with high specific volume and good quality can be prepared. Meanwhile, the method is quick and efficient in process, suitable for mass production, also suitable for people with autoimmune diseases caused by food allergy, celiac disease, gluten sensitivity and the like, and has practical value.

The invention provides a heat pump device, a control method of the heat pump device, and a control device of the heat pump device. The heat pump equipment comprises a compressor, an evaporator and a condenser. A refrigerant outlet of the evaporator is connected with a refrigerant auxiliary path, the refrigerant auxiliary path is connected with an air suction port of the compressor, an auxiliary heat exchanger is arranged on the refrigerant auxiliary path, and the auxiliary heat exchanger is arranged at a part of the refrigerant pipeline between the refrigerant outlet of the condenser and the electronic expansion valve and exchanges heat with the refrigerant pipeline. According to the equipment, the refrigerant heat exchanger is additionally arranged, low-temperature refrigerants flowing out of the evaporator and high-temperature refrigerants flowing out of the condenser are subjected to heat exchange, on one hand, the compressor properly sucks air to be overheated, the specific volume of the air suction state is increased, the density is reduced, at the moment, the compressor does not need to be excessively decelerated, and the mass flow can also be reduced; on the other hand, outlet liquid of the condenser is supercooled, so that the enthalpy value of a refrigerant behind the electronic expansion valve is reduced, and the heat exchange capacity of the evaporator is improved; and under the condition that the compressor is ensured to be at a relatively high rotating speed, the input power is reduced, the output capacity is reduced and the energy efficiency is improved.

The invention provides a preparation method and application of a high-specific-volume conjugated carbonyl organic compound material which can be used as a positive electrode material in an alkali metal battery and has large-scale synthesis potential. The material realizes reversible energy storage by utilizing O atoms to coordinate metal ions, has the advantages of multiple reaction sites, intramolecular conjugated structures and high specific capacity, the specific capacity is higher than that of most of current conjugated carbonyl compounds, the theoretical capacity is 449mAh / g, the actual capacity is 442mAh / g, and the voltage is higher in an organic N-type material. The material can be synthesized through simple reaction, and is low in reaction temperature, simple in condition and easy to amplify. And the electrolyte concentration is regulated and controlled to obtain a formula capable of inhibiting micromolecule dissolution and improving the cycle retention rate. And the lithium metal soft package battery is assembled, and the application potential is shown.

The invention provides a steam turbine optimal configuration system arranged at a high position and a low position, which at least comprises a high-position shaft system, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a generator, a low-pressure cylinder, a generator, a first condenser and a second condenser, wherein the high-position shaft system is arranged close to the elevation position of an inlet header and an outlet header of a superheater and a reheater; the low-pressure cylinder and the generator are arranged on a low-position shaft system; the steam guide pipe is connected between a low-pressure cylinder on the high-position shaft system and the first condenser, the communicating pipe is connected with the steam exhaust end of a medium-pressure cylinder on the high-position shaft system, the steam inlet end of the low-pressure cylinder on the high-position shaft system and the steam inlet end of the low-pressure cylinder on the low-position shaft system, and the valve is arranged at the steam inlet end of the low-pressure cylinder on the low-position shaft system. And the steam in the communicating pipe in front of the steam inlet valve of the low-pressure cylinder on the low-position shaft system enters a heating heat exchange station through a heating valve and a pipeline. By means of the heating valve and a low-pressure cylinder steam inlet valve on the low-position shaft system, steam inlet of a low-pressure cylinder on the low-position shaft system can be adjusted according to specific seasons and loads, so that the commissioning and removing functions of the low-position shaft system are achieved, the steam inlet amount in the heating seasons is adjusted, and the heating steam pressure is maintained. Therefore, the optimal all-season and full-load operation condition is realized, and the purposes of saving energy and reducing consumption are achieved.

The invention discloses a method for making pre-baked frozen bread by using lactic acid bacteria to ferment sour dough, and belongs to the technical field of food processing. The method is characterized by comprising the following process steps: (1) preparation and storage of sour dough: S10, inoculated fermentation of the sour dough; S20, enlarged culture fermentation of the sour dough; S30, preparation of the sour dough; and S40, storage of the sour dough. And (2) S50, making the pre-baked frozen bread based on the sour dough: uniformly mixing the sour dough with other ingredients, kneading dough, forming, fermenting, baking, packaging, freezing and re-baking. According to the method for making the pre-baked frozen bread by using the sour dough fermentation technology, the flavor characteristics of the pre-baked frozen bread are effectively improved, the tissue structure and freshness of the bread are remarkably improved and the aging rate is delayed through the generation of lactobacillus fermentation metabolites including organic acids and flavor compound precursors (free amino acids) in the sour dough.

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.