阅读说明：本技术 一种利用微波真空处理提高酿造酱油鲜度的方法 (Method for improving freshness of brewed soy sauce by microwave vacuum treatment ) 是由 田玉庭 张翀 蒋雅君 庄玮婧 郑宝东 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种利用微波真空处理提高酿造酱油鲜度的方法,该方法包括豆粕的常压润水处理、微波真空处理、混料调湿、制作成曲、大罐发酵的步骤,其具体是对润水后的豆粕采用三段式微波真空处理,配以麸皮、古田红曲粉混料,并用米曲霉沪酿3.042为主的曲精控温控湿进行制曲工艺,在玻璃纤维材料发酵罐中以高盐稀态发酵方法进行露天发酵。本发明方法可稳定控制原料蛋白质变性,提高原料蛋白质的利用率和氨基酸生成率,经济效益显著；且所得酿造酱油风味醇厚、口感鲜甜、色泽明亮,氨基酸含量高。(The invention discloses a method for improving the freshness of brewed soy sauce by utilizing microwave vacuum treatment, which comprises the steps of normal-pressure moistening treatment of soybean meal, microwave vacuum treatment, mixing and humidifying, yeast making and large-tank fermentation, and particularly comprises the steps of performing three-stage microwave vacuum treatment on the moistened soybean meal, mixing bran and gulian red yeast powder, performing yeast making by using yeast essence with the main part of Aspergillus oryzae Huniang 3.042 at controlled temperature and humidity, and performing open-air fermentation in a glass fiber material fermentation tank by using a high-salt dilute state fermentation method. The method can stably control the denaturation of the raw material protein, improve the utilization rate of the raw material protein and the generation rate of amino acid, and has remarkable economic benefit; the brewed soy sauce has mellow flavor, fresh and sweet taste, bright color and high amino acid content.)

1. a method for improving the freshness of brewed soy sauce by utilizing microwave vacuum treatment is characterized by comprising the following steps: the method comprises the following steps:

(1) And (3) bean pulp moistening treatment: putting the bean pulp into a V-shaped mixer, adding 0.5mL of purified water into each gram of the bean pulp, adding water, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min;

(2) performing microwave vacuum treatment on the soybean meal, namely placing the moistened soybean meal in a cavity of microwave vacuum equipment for three ~ stage microwave vacuum treatment, wherein the microwave intensity is 20 ~ 25W/g, the temperature is 90 ~ 95 ℃, and the material thickness is 3 ~ 5 cm;

(3) Mixing and humidifying: fully mixing the bean pulp subjected to microwave vacuum treatment with bran and red yeast rice powder according to a certain ratio, and controlling the water content of the mixture to be 48-50 wt%;

(4) Preparing a yeast: inoculating activated yeast extract into the mixture after the humidity adjustment, uniformly stirring, and then feeding the mixture into a yeast pool for loosening and flattening for culture, wherein the flattening thickness is controlled to be 35-45 cm; controlling the temperature of the koji room at 30-33 ℃, controlling the relative humidity at 80-85%, and intermittently ventilating to control the product temperature at 34-36 ℃; after 14h, performing primary bending turning when cracks are generated on the surface of the bent material, and adjusting the temperature of a bending room to 28 ℃; turning over the yeast for the second time when the yeast materials are completely white and caked at 20 h; culturing for 28h, and then discharging the yeast to obtain finished yeast;

(5) large tank fermentation: smashing the finished koji, mixing the smashed finished koji with 16-18 wt% of saline water to form thin mash, and naturally fermenting for more than 180 days.

2. The method of claim 1, wherein the microwave vacuum treatment is used to enhance the freshness of the brewed soy sauce: the average grain size of the soybean meal used in the step (1) is 3 mm.

3. The method of claim 1, wherein the microwave vacuum treatment is used to enhance the freshness of the brewed soy sauce: the three-stage microwave vacuum treatment in the step (2) comprises the following specific steps: the first stage vacuum degree is controlled to be-70 kPa to-75 kPa, and the treatment time is 30 s; the vacuum degree of the second stage is controlled to be-80 kPa to-85 kPa, and the treatment time is 120 s; the vacuum degree of the third stage is controlled between-85 kPa and-90 kPa, and the treatment time is 30 s.

4. The method of claim 1, wherein the microwave vacuum treatment is used to enhance the freshness of the brewed soy sauce: in the step (3), the mass ratio of the soybean meal to the bran to the red yeast rice powder is 70:20: 10;

The red yeast rice powder is prepared by crushing the Fujian Gutian red yeast rice and sieving the crushed red yeast rice with a 60-mesh sieve, wherein the color value of the red yeast rice powder is more than or equal to 700U/g, and the saccharifying power of the red yeast rice powder is more than or equal to 600.

5. The method of claim 1, wherein the microwave vacuum treatment is used to enhance the freshness of the brewed soy sauce: the amount of the activated yeast extract added in the step (4) is 1.2 percent of the weight of the dry materials of the mixture;

the activated koji is prepared by mixing and diluting koji with flour 30 times of the weight of the koji before inoculation;

The yeast extract is prepared from Aspergillus oryzae Huniang 3.042, Aspergillus oryzae Huniang UE336-2 and Aspergillus niger AS3.350 in a weight ratio of 12: 5: 3, the spore number is not less than 10 hundred million per gram of yeast dry base, and the spore germination rate is not less than 90 percent.

6. the method of claim 1, wherein the microwave vacuum treatment is used to enhance the freshness of the brewed soy sauce: the weight ratio of the mixture of the koji in the step (5) and the saline water is 1g:3 mL.

Technical Field

the invention belongs to the technical field of food processing, and particularly relates to a method for preparing high-fresh soy sauce by microwave vacuum treatment.

background

Soy sauce is a traditional fermented condiment, and at present, bean pulp, bran and the like are generally used as raw materials for brewing the soy sauce, protein, starch and fat in the raw materials are decomposed through the action of an enzyme system of microorganisms, so that composite fermented glutinous rice containing amino acid, sugar, glycerol, organic acid and the like is formed, and the soy sauce is produced into the condiment with bright color, thick flavor and fresh and sweet taste through long-time after-ripening fermentation. The production process of the brewed soy sauce is generally divided into two main types of high-salt dilute state and low-salt solid state, and the soy sauce brewed by the high-salt dilute state method has better flavor and is favored by consumers, so the method becomes the mainstream method for producing the soy sauce. The soy sauce yeast extract taking aspergillus oryzae Shanghai brewing 3.042 as a main strain is a starter propagation strain used by most soy sauce production enterprises at present. The yeast extract is prepared by multi-strain mixed fermentation, can be directly used and prepared into yeast, saves the production time and cost of the yeast, and has the advantages of fast strain growth, sufficient spore yield and wide enzyme system range. The quality grading of the soy sauce is based on the content of amino acid nitrogen, and according to the standard of brewing soy sauce in China, the amino acid nitrogen is not less than 0.8 g/100ml in a special grade, not less than 0.7 g/100ml in a first grade, not less than 0.55 g/100ml in a second grade, and not less than 0.4 g/100ml in a third grade. The higher the protein utilization rate and the higher the content of amino acid nitrogen, the better the quality of the soy sauce, and the more delicious the soy sauce. The content of amino acid nitrogen in the delicious soy sauce in the domestic market is generally more than 1.2g/100mL, which exceeds one level of the national standard. With the gradual change of consumption concept, people prefer soy sauce with good color, aroma and taste, namely, high-quality soy sauce also needs to have good color and more aromatic flavor. The appearance of the delicious soy sauce meets the requirement of the market for high-quality soy sauce, and the market potential of the delicious soy sauce is huge. Therefore, the development of the delicious soy sauce has wide market prospect.

the soybean meal is used as a protein raw material of the soy sauce, and can be subjected to enzymolysis and utilization by protease only after being subjected to proper pretreatment and denaturation, and if the denaturation degree is too low, the raw material cannot be thoroughly decomposed, and the utilization rate of the protein and the generation rate of amino acid cannot be improved; if the soybean meal is excessively denatured, the fermented product will have N-type protein precipitation, and the quality of the soy sauce is reduced. The conventional protein denaturation method is atmospheric pressure cooking, and then the japanese high pressure cooking technology is introduced, and it is the most widely used treatment method at present. In the processing process, the problems of uneven protein denaturation degree are easily caused due to the fact that the material thickness is not uniform enough and the air pressure in a steam pot is unstable, so that the utilization rate of total nitrogen of the protein raw material is low (Liyue, the experimental study on the soy sauce brewed by extruding, puffing bean pulp and wheat flour [ D ]. Shandong university of science and technology.2014). At present, soy sauce manufacturers represented by Japan Tortoise Shell Wan soy sauce company adopt a processing method of puffing as a soy sauce raw material to replace the traditional steaming method, and the utilization rate of the soy sauce raw material is improved to more than 90 percent. The patent reports on the aspects of the extrusion puffing pretreatment of the bean pulp and the airflow puffing pretreatment of the bean pulp can ensure that the protein denaturation degree is uniform and appropriate, the protein utilization rate is high, and thus the pretreatment and yeast making cost is reduced. But has the disadvantages that the invention patent 'a method for preparing yeast by using an extrusion-puffed soybean meal and flour mixture' (CN 103610024A) has higher caking degree of the processed material, needs to spend more time in smashing before preparing thin mash, has more complicated operation steps, and has lower output of extrusion-puffing equipment and high equipment loss; the invention discloses a method for brewing high-fresh soy sauce by using superheated steam puffed soybean meal starter propagation (CN 107927709A), which takes a long time to reduce the temperature of raw materials after the treatment is finished, so that the inoculation treatment can be carried out, excessive denaturation is possibly caused, and the treatment steps are complicated. Therefore, it is very important to find a soy sauce raw material which can stably control the protein denaturation degree and reduce the production cost.

At present, no literature report that the microwave vacuum pretreatment of the soybean meal is used for making starter for brewing soy sauce is found in the raw material pretreatment method. The microwave vacuum treatment technology combines the advantages of direct heating of materials by microwave dielectric heating and acceleration of water diffusion speed in a vacuum environment, and has the characteristics of high-efficiency heat transfer, uniform heating, easy regulation and control, high product quality and the like. In addition, microwave vacuum treatment can make the material evenly denature fast and destroy the structure and produce the micro-swelling effect. Meanwhile, the microwave can also destroy the physiological structure of microorganisms in the material to achieve the sterilization effect, thereby reducing the possibility of generating mixed bacteria. The microwave vacuum treatment can simultaneously complete the procedures of protein denaturation, starch disintegration, sterilization and the like, and is beneficial to the conversion of the protein. The invention mainly utilizes the microwave vacuum treatment process of the bean pulp raw material and adopts a three-section control vacuum treatment method to ensure that the protein is properly denatured, red yeast rice powder is added into the raw material and yeast is directly used for multi-strain yeast preparation, the yeast preparation process is optimized, the red yeast rice powder is added into the fermentation liquor to optimize the high-salt dilute state fermentation process, the protein utilization rate and the amino acid generation rate are improved, and the soy sauce with outstanding delicate flavor and red and bright color is produced.

disclosure of Invention

the invention aims to provide a method for improving the freshness of brewed soy sauce by utilizing microwave vacuum treatment, which adopts a microwave vacuum treatment technology to replace the traditional raw material pretreatment mode of high-pressure cooking, can effectively control the protein denaturation degree of the soy sauce raw material, and is matched with a multi-strain temperature and humidity control starter propagation process and a high-salt dilute state fermentation process, thereby brewing the soy sauce with mellow flavor, fresh and sweet taste, bright color and high amino acid content.

in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a method for improving freshness of brewed soy sauce by using microwave vacuum treatment comprises the following steps:

(1) And (3) bean pulp moistening treatment: putting the bean pulp into a V-shaped mixer, adding 0.5mL of purified water into each gram of the bean pulp, adding water, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min;

(2) performing microwave vacuum treatment on the soybean meal, namely placing the soybean meal after being moistened into a cavity of microwave vacuum equipment for three ~ stage microwave vacuum treatment, wherein the first stage of vacuum degree is controlled to be ~ 70kPa to ~ 75kPa, the treatment time is 30s, the second stage of vacuum degree is controlled to be ~ 80kPa to ~ 85kPa, the treatment time is 120s, the third stage of vacuum degree is controlled to be ~ 85kPa to ~ 90kPa, the treatment time is 30s, the microwave intensity is 20 ~ 25W/g, the temperature is 90 ~ 95 ℃, and the material thickness is about 3 ~ 5 cm;

(3) Mixing and humidifying: fully mixing the bean pulp subjected to microwave vacuum treatment with bran and red yeast rice powder according to a certain ratio, and controlling the water content of the mixture to be 48-50 wt%;

(4) preparing a yeast: inoculating activated yeast extract into the mixture subjected to humidifying at 35-40 ℃, uniformly stirring, and then feeding the mixture into a yeast pool for loosening and flattening for culture, wherein the flattening thickness is 35-45 cm; controlling the temperature of the koji room at 30-33 ℃, controlling the relative humidity at 80-85%, and intermittently ventilating to control the product temperature at 34-36 ℃; after 14h, performing primary bending turning when cracks are generated on the surface of the bent material, and adjusting the temperature of a bending room to 28 ℃; when the yeast materials are all white at 20h, and when the yeast materials are caked, performing secondary yeast turning; culturing for 28h, and then discharging the yeast to obtain finished yeast;

(5) large tank fermentation: smashing finished yeast, mixing the smashed finished yeast with 16-18 wt% of saline water according to the weight ratio of 1g:3mL to form diluted mash, pumping the diluted mash into a glass fiber fermentation tank, and naturally fermenting for more than 180 days by a high-salt diluted state fermentation method.

the soybean meal used in the step (1) is non-transgenic soybean meal which is loose granular, the average grain diameter is 3mm, and other quality indexes meet GB/T19541-2004.

In the step (3), the mass ratio of the soybean meal to the bran to the red yeast rice powder is 70:20: 10; the red yeast rice powder is prepared by crushing the Fujian Gutian red yeast rice and sieving the crushed red yeast rice with a 60-mesh sieve, wherein the color value of the red yeast rice powder is more than or equal to 700U/g, and the saccharifying power of the red yeast rice powder is more than or equal to 600.

the amount of the activated yeast extract added in the step (4) is 1.2 percent of the weight of the dry materials of the mixture; the activated koji is prepared by mixing and diluting koji with flour 30 times of the weight of the koji before inoculation; the yeast essence is prepared from Aspergillus oryzae Shanghai brewing 3.042, Aspergillus oryzae Shanghai brewing UE336-2 and Aspergillus niger AS3.350 in a weight ratio of 12: 5: 3, matching and preparing; the number of spores in the yeast extract is not less than 10 hundred million per gram of yeast dry base, and the germination rate of the spores is not less than 90%.

The invention has the beneficial effects that:

(1) The invention adopts three-stage microwave vacuum treatment, can obtain properly denatured protein raw materials, increases the digestibility of the soybean meal, the content of water-soluble protein and the gelatinization degree, and can obviously improve the total amount of amino acids in the finished koji, particularly the content of aspartic acid (4.74%) and glutamic acid (7.64%).

(2) The method is simple and convenient to operate, and the effects of moderate protein denaturation, high starch gelatinization degree, bacteria killing and the like can be realized only by using the microwave vacuum for treating the soybean meal for 180 s.

(3) the three-stage vacuum treatment of the invention can make the protein denaturation degree easier to control, the raw material has higher puffing degree and stronger cracking property, and the utilization rate of the raw material protein and the conversion rate of amino acid in the brewed soy sauce are obviously improved (respectively 91.98 percent and 65.14 percent), thereby having great economic benefit.

drawings

FIG. 1 shows the effect of microwave vacuum treatment on digestibility, water-soluble protein content and gelatinization degree of different soybean meals;

FIG. 2 shows the effect of different soybean meal treatment processes on digestibility, water-soluble protein content and gelatinization degree;

FIG. 3 shows the effect of different soybean meal treatment processes on the contents of 9 main amino acids and total amino acids;

FIG. 4 is a graph showing the effect of using soybean meal from different processes as a raw material on the content of amino acids in the resulting koji.

Detailed Description

1. The influence of the one-stage, two-stage and three-stage microwave vacuum treatment processes on the quality of the soybean meal is examined:

Test 1: the influence of different microwave vacuum treatment processes on the digestibility, water-soluble protein and gelatinization degree of the soybean meal.

a first section I: putting the bean pulp into a V-shaped mixer, adding water according to the calculation of adding 0.5mL of purified water into each gram of bean pulp, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min; and (3) placing the bean pulp after being moistened with water in a cavity of microwave vacuum equipment for one-stage microwave vacuum treatment. The microwave intensity is 20W/g, the temperature is 90 ℃, the material thickness is about 3cm, the vacuum degree is controlled to be minus 80kPa to minus 85kPa, and the treatment is carried out for 180 s.

a two-stage type II: putting the bean pulp into a V-shaped mixer, adding water according to the calculation of adding 0.5mL of purified water into each gram of bean pulp, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min; and (4) placing the bean pulp after being moistened with water in a cavity of microwave vacuum equipment for two-stage microwave vacuum treatment. The microwave intensity is 20W/g, the temperature is 90 ℃, the material thickness is about 3cm, the first period of treatment time is 30s, and the vacuum degree is controlled to be-70 to-75 kPa; the second stage treatment time is 150s, and the vacuum degree is controlled between-80 kPa and-85 kPa.

three-stage type III (the process of the invention): putting the bean pulp into a V-shaped mixer, adding water according to the calculation of adding 0.5mL of purified water into each gram of bean pulp, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min; putting the bean pulp after being moistened into water in a cavity of microwave vacuum equipment for three-stage microwave vacuum treatment, wherein the microwave intensity is 20W/g, the temperature is 90 ℃, the material thickness is about 3cm, the first-stage treatment time is 30s, and the vacuum degree is controlled to be-70 to-75 kPa; the second stage treatment time is 120s, and the vacuum degree is controlled to be-80 kPa to-85 kPa; the treatment time of the third stage is 30s, and the vacuum degree is controlled between-85 kPa and-90 kPa.

as can be seen from FIG. 1, the indexes of digestibility, soluble protein content and gelatinization degree of the soybean meal after one ~ stage, two ~ stage and three ~ stage treatment in the microwave vacuum treatment process of different soybean meals tend to rise, wherein the digestibility, water ~ soluble protein content and gelatinization degree of the soybean meal are obviously increased (respectively increased by 6.29 ~ 7.73%, 3.74 ~ 5.05% and 8.90 ~ 11.26%) compared with the three ~ stage and two ~ stage treatment processes, so that the three ~ stage microwave vacuum treatment process is more beneficial to properly denature the soybean meal.

2. The influence of the traditional cooking process, the extrusion puffing process, the superheated steam puffing process and the process of the invention on the quality of the soybean meal and the finished koji prepared from the soybean meal is examined:

adding the soybean meal into a steamer for steaming at a material ~ water ratio of 1:1, wherein the pressure of the steamer is 1.50 ~ 1.60MPa, and the time is 40 ~ 60 min;

② extrusion puffing process: according to the invention, the method for preparing the starter by using the mixture of the extruded and puffed soybean meal and the flour (CN 103610024A) has the specific parameters that the moisture content of the soybean meal is adjusted to 23-23.4 wt%, the soybean meal is placed in a single-screw extrusion puffing machine for extrusion puffing treatment, the temperature of four sections of sleeves is respectively set to be 30-32 ℃, 54-55 ℃, 79-81 ℃, 93-95 ℃, the rotating speed of a screw is 196-200 r/min, and the diameter of a die hole is set to be 8-10 mm;

the invention relates to a superheated steam puffing process, in particular to a method for brewing high ~ fresh soy sauce by using superheated steam puffed soybean meal starter propagation (CN 107927709A), which has the specific parameters that the moisture content of the soybean meal is adjusted to be 20.1 ~ 21.0wt%, the soybean meal is preheated at the normal pressure of 108 ℃ and then is subjected to superheated steam puffing treatment, the soybean meal is vacuumized to 30Pa, the steam pressure is 1.51 ~ 1.60MPa, the steam temperature is 190 ~ 200 ℃, the residence time is 200 ~ 219s, and the soybean meal is decompressed within 0.1 s;

The process of the invention: putting the bean pulp into a V-shaped mixer, adding water according to the calculation of adding 0.5mL of purified water into each gram of bean pulp, controlling the rotating speed of the mixer to be 10-15 r/min, and carrying out water moistening treatment for 30 min; putting the bean pulp after being moistened into water in a cavity of microwave vacuum equipment for three-stage microwave vacuum treatment, wherein the microwave intensity is 20W/g, the temperature is 90 ℃, the material thickness is about 3cm, the first-stage treatment time is 30s, and the vacuum degree is controlled to be-70 to-75 kPa; the second stage treatment time is 120s, and the vacuum degree is controlled to be-80 kPa to-85 kPa; the treatment time of the third stage is 30s, and the vacuum degree is controlled between-85 kPa and-90 kPa.

test 2: the influence of different bean pulp treatment processes on the digestibility, the water-soluble protein and the gelatinization degree of the bean pulp.

the digestibility, the water-soluble protein content and the gelatinization degree of the soybean meal (the digestibility of the soybean meal is determined by an SB/T103191999 enzymolysis method, the water-soluble protein content of the soybean meal is determined by NY/T1205-2006, the gelatinization degree is determined by an amylase method, and the amino acid nitrogen of the soy sauce is determined by a GB/T5009-39-2003 formaldehyde value method) are respectively determined after the soybean meal is treated according to the process, and the results are shown in figure 2.

as can be seen from fig. 2, compared with the conventional cooking process and the conventional extrusion process, the digestion rate, the water-soluble protein content and the gelatinization degree of the soybean meal subjected to the superheated steam puffing process and the microwave vacuum treatment of the present invention are all significantly improved, and the effect of the microwave vacuum treatment process is further improved compared with the superheated steam puffing process.

Test 3: the influence of different bean pulp treatment processes on the total amount of amino acids and the composition thereof.

the total amount of amino acids in the soybean meal and the composition of 9 main amino acids in the soybean meal are respectively determined after the soybean meal is processed according to the process (the amino acids in the soybean meal are determined by the method of GB 5009.124-2016), and the result is shown in figure 3.

As can be seen from fig. 3, compared with the conventional cooking process and the conventional extrusion process, the contents of 9 amino acids in the soybean meal samples treated by the superheated steam puffing process and the microwave vacuum process of the present invention are both significantly increased, while the contents of the amino acids treated by the microwave vacuum process are significantly higher than the first three, wherein the contents of aspartic acid and glutamic acid are respectively increased by 0.30% and 0.35% and the total amount of the amino acids is increased by 3.07% compared with the conventional method. The microwave vacuum treatment process used in the invention has obvious effect on improving the quality of the soybean meal.

test 4: influence of different soybean meal treatment processes on the total amount and composition of koji-forming amino acids.

The bean pulp respectively treated according to the process is used as raw materials for preparing the koji, and the koji preparation method respectively prepares koji (the bean pulp raw material treated by the traditional cooking process), koji (the bean pulp raw material treated by the extrusion puffing process), koji (the bean pulp raw material treated by the superheated steam puffing process) and koji (the bean pulp raw material treated by the microwave vacuum process).

specifically, the ratio of the bean pulp to the bran is 4:1, the water content of the mixture is controlled to be 45-50wt%, and the used yeast extract is prepared by mixing 12 parts by weight of Aspergillus oryzae Humian 3.042, Aspergillus oryzae Humian UE336-2 and Aspergillus niger AS 3.350: 5: 3, the spore number is more than 10 hundred million/g yeast dry basis, and the spore germination rate is not less than 90 percent; mixing and diluting the obtained koji with flour which is 30 times of the weight of the koji to prepare activated koji; taking activated yeast extract accounting for 1.2% of the dry material weight of the mixture, inoculating and uniformly stirring the activated yeast extract in the mixture at the temperature of 35-40 ℃, and then feeding the mixture into a yeast pool for loosening and flattening, wherein the flattening thickness is controlled to be 35-45 cm; controlling the temperature of the koji room at 30-33 ℃, and intermittently ventilating to control the product temperature at 34-36 ℃; after 14h, performing primary bending turning when cracks are generated on the surface of the bent material, and adjusting the temperature of a bending room to 28 ℃; when the yeast materials are all white at 20h, and when the yeast materials are caked, performing secondary yeast turning; culturing for 28h, and then discharging the yeast to obtain finished yeast; during the cultivation period, the relative humidity is controlled to be 80-85%. After the finished koji is cultured, samples are frozen by using an ultra-low temperature refrigerator, then the amino acid contents of the finished koji (R), the finished koji (R) and the finished koji (R) are detected (the amino acid in the finished koji is detected by adopting a method for detecting the amino acid in GB 5009.124-2016 food), the influence of the raw materials after different pretreatments on the amino acid generated by the finished koji is known, and the result is shown in figure 4.

As can be seen from fig. 4, the amino acid content in the koji made from the raw material of soybean meal processed by extrusion and expansion is substantially the same as, and has no significant change, compared with the amino acid content in the koji made from the raw material of soybean meal processed by the conventional cooking process; the contents of 9 main amino acids and total amino acids in the finished koji prepared from the soybean meal raw material subjected to superheated steam puffing treatment and the finished koji prepared from the soybean meal raw material subjected to microwave vacuum treatment are obviously improved, wherein the contents of aspartic acid, glutamic acid, leucine and arginine in the finished koji prepared from the soybean meal raw material subjected to microwave vacuum treatment are obviously improved compared with other amino acids.

in order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Preparing red yeast rice powder: red yeast rice is purchased from Hua L Red Rice Limited company in Fujian Gutian county, and after being crushed, the red yeast rice is sieved by a 60-mesh sieve, and the color value and the saccharifying power of the red yeast rice are measured by reference documents. (Zhang Jian. Fujian representative Red Yeast Rice research and its Standard establishment [ D ], Fujian agriculture and forestry university, 2011).