Composite soybean paste and preparation method thereof

Abstract

The invention discloses a composite soybean paste which comprises the following components in parts by weight: 1400-1800 parts of soybeans, 200-600 parts of black beans and 200-480 parts of food-grade sodium chloride. The preparation method of the composite soybean paste comprises the following steps: selecting soybeans and black beans as raw materials; step-by-step atomization inoculation starter propagation; fermenting with mixed bacteria saline water; performing microwave synergistic pasteurization: performing microwave irradiation treatment on the soybean paste, and performing pasteurization treatment on the soybean paste subjected to the microwave irradiation treatment to obtain a finished product of the composite soybean paste. The composite soybean paste prepared by the method is reddish brown, is rich in nutritional values of soybeans and black beans, greatly improves the nutritional quality and characteristic flavor of the soybean paste, has the characteristics of rich nutrition, mellow delicate flavor, palatable salty taste, stable quality and the like, and provides a new way for development of coarse cereal products with high additional values.

Description

Technical Field

[0001] The invention relates to the technical field of condiment processing, and in particular provides a composite bean paste and a preparation method thereof. Background Art

[0002] Bean paste has a long history in my country and is an indispensable side dish in people's lives. Bean paste is made from soybeans as the main raw material, through koji making and fermentation, and is a microbial fermented food. In recent years, with the improvement of people's lives, the flavor and nutrition of bean paste and how to meet the needs of different groups of people have become issues of concern to researchers and producers of bean paste condiments. The main raw material of traditional bean paste is soybeans. Its nutritional advantages are that it is rich in high-quality protein, rich in cellulose, and high in trace elements, but it also contains some adverse ingredients. For example, beans contain anti-nutritional substances such as saponins and trypsin inhibitors. High levels of intake may interfere with pancreatic function and digestion and absorption. In addition, the bean paste made from pure soybeans is lighter in color. Some commercially available soybean pastes adjust the color of the sauce by adding food additives such as caramel color and red yeast rice, which not only increases the production cost but also increases the risk of food safety.

[0003] Traditional naturally fermented soybean paste is usually carried out from March to October. If fermented at a lower temperature, it will produce a less mellow taste, poor flavor, and poor quality. There is a long production window period, which is not conducive to the industrialized year-round mass production of soybean paste.

[0004] In summary, in view of the above-mentioned problems, a preparation process of bean paste is provided to obtain a low-temperature-resistant and nutritious composite bean paste, which has become an urgent problem to be solved. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a composite bean paste and a preparation method thereof, so as to solve the problems of incomplete fermentation due to low temperature, poor taste, incomplete nutrition, insufficient taste and poor appearance in the existing bean paste preparation process.

[0006] The technical solution provided by the invention is: a composite bean paste, which comprises, by weight, 1400-1800 parts of soybeans, 200-600 parts of black beans, and 200-480 parts of food-grade sodium chloride.

[0007] The present invention also provides a method for preparing a composite bean paste, comprising the following steps:

[0008] Step 1: Select soybeans and black beans as raw materials, and pre-treat them to obtain black bean materials and soybean materials;

[0009] Step 2: Stepwise atomization inoculation and koji making: spray the Pichia pastoris solution into the black soybean material, stir evenly, and let it stand for fermentation; spray the amyloglucosidase solution into the soybean material, stir evenly, and let it stand for fermentation;

[0010] After fermentation, the black bean material and the yellow bean material are respectively made into block-shaped fermented grains, and fermented until white, green or yellow bacteria grow in the fermented grains, and the koji making is completed to obtain black bean fermented grains and yellow bean fermented grains;

[0011] Step 3: mixed bacteria salt water fermentation: the surfaces of the black bean paste and the soybean paste are treated to remove mycelium respectively, the black bean paste and the soybean paste are crushed and mixed to obtain a paste, Lactobacillus and Pediococcus are inoculated into the paste, and the paste is mixed with salt water, put into a sauce jar, covered with gauze, exposed to the sun, pressed regularly, and fermented continuously to obtain soybean paste;

[0012] Step 4: Microwave-assisted pasteurization: subjecting the soybean paste to microwave irradiation treatment, and then subjecting the soybean paste after microwave irradiation treatment to pasteurization treatment to obtain a finished composite soybean paste.

[0013] Preferably, the pretreatment of raw materials in step 1 includes: screening, removing impurities, washing and crushing the black beans and the yellow beans respectively, and then performing hot air puffing; wherein the crushing is followed by sieving the beans, and the mesh size of the sieve is 5-20 meshes; the hot air puffing is carried out by high temperature and short time hot air puffing, wherein the puffing temperature of the hot air circulation oven is 140-160°C, and the puffing time is 40-200s.

[0014] Preferably, in step 2, the mass percentage of the atomized spraying of the Pichia pastoris solution is 0.1-1.0% based on the dry basis of black beans, the static fermentation time is 2-6 hours, the fermentation temperature of the black bean block mash is 20-60° C., and the fermentation time is 40-90 hours;

[0015] The atomized spraying amount of the amyloglucosidase solution is 0.2-1.5% based on the dry soybean basis, the static fermentation time is 2-6 hours, the fermentation temperature of the soybean block mash is 20-60° C., and the fermentation time is 40-90 hours.

[0016] Preferably, in step 3, Lactobacillus and Pediococcus are inoculated into the mash and stirred evenly with salt water, wherein the mass concentration of the salt water is 5-30%; the Lactobacillus and Pediococcus are one or more of Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22;

[0017] Preferably, when Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22 are added, the strain ratio is 1:1:1, and the total inoculation amount is 0.1-2.0%.

[0018] Preferably, in step 3, the continuous fermentation process is: stirring is performed every day in the first week, and stirring is performed 2-3 times every seven days starting from the second week until the fermentation is completed, and the fermentation time is 30-60 days.

[0019] Preferably, in step 4, the pasteurization treatment parameters are: microwave power of 500-900 W, microwave time of 60-120 s; pasteurization temperature of 70-120° C., and pasteurization time of 5-25 min.

[0020] The present invention provides a composite bean paste and a preparation method thereof. The preparation method produces a composite bean paste with rich nutrition, mellow sauce flavor and outstanding umami taste through the processes of selecting, crushing, hot air puffing, step-by-step koji making and low-temperature resistant mixed bacteria salt water fermentation of composite raw materials of black beans and yellow beans;

[0021] With soybeans and black beans as the main raw materials, it has the advantages of rich nutrition and short sauce making time, and realizes natural fermentation under low temperature environment. The composite bean paste adopts high temperature and short time hot air puffing technology to replace the traditional steaming technology, which can maintain the nutrition of beans to the greatest extent and shorten the pre-processing time. According to the difference between soybean and black bean raw materials, the method of step-by-step atomization inoculation koji making and low temperature mixed bacteria brine fermentation is adopted to solve the problem of difficulty in fermenting soy products under low temperature environment.

[0022] The composite bean paste prepared by the invention is reddish brown in color and rich in the nutritional value of soybeans and black beans, which greatly improves the nutritional quality and characteristic flavor of the bean paste. It has the characteristics of rich nutrition, mellow fresh taste, palatable salty taste, stable quality, etc., and provides a new way for the development of high value-added grain products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0024] Figure 1 The figure is a schematic diagram of the preparation method of the composite bean paste of the present invention;

[0025] Figure 2 Schematic diagram comparing the amino acid nitrogen and appearance of the composite bean paste obtained in the embodiment of the present invention and the comparative example;

[0026] Figure 3 Schematic diagram showing the comparison of flavor substances in the bean paste obtained in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below.

[0028] Black beans, which belong to the same genus as soybeans, have higher nutritional value than soybeans, such as gamma-linolenic acid, anthocyanins and flavonoids, which help eliminate free radical damage. The nutritional and functional components of black beans can not only make up for the nutritional shortcomings of soybean paste, which is mainly made of soybeans, but also enrich the flavor, color and variety of soybean paste.

[0029] As people's demand for food nutrition becomes increasingly diverse, comprehensive and balanced, the seasoning market needs compound bean paste that can meet the taste, nutrition and safety requirements of different consumers.

[0030] First, this embodiment provides a composite bean paste, which includes, by weight: 1400-1800 parts of soybeans, 200-600 parts of black beans, and 200-480 parts of food-grade sodium chloride.

[0031] In addition, this embodiment also provides a method for preparing the above-mentioned composite bean paste, comprising the following steps:

[0032] Step 1: Select soybeans and black beans as raw materials, and pre-treat them to obtain black bean materials and soybean materials;

[0033] The raw materials are pre-treated as follows: black beans and yellow beans are screened, cleaned, washed, appropriately crushed, and subjected to hot air puffing to obtain black bean materials and yellow bean materials;

[0034] Preferably, the raw black beans and soybeans in step 1 are crushed and sieved with a mesh size of 5-20. The technical parameters of high temperature short time hot air puffing are that the puffing temperature of the hot air circulation oven is 140-160°C and the puffing time is 40-200s.

[0035] Black beans, one of the main ingredients of the composite bean paste in the present invention, not only have all the nutritional elements of soybeans, but also have about a quarter more high-quality protein than soybeans and a reasonable fatty acid ratio. In addition, black bean saponins and black bean pigments, which are unique nutritional elements in black beans, have DNA damage protection and antioxidant effects, making the bean paste more nutritious.

[0036] Step 2: Step-by-step atomization inoculation and koji making: Spray the Pichia pastoris solution onto the black bean material treated in step 1, stir evenly, and let it stand for fermentation; spray the amyloglucosidase solution onto the soybean material treated in step 1, stir evenly, and let it stand for fermentation. After fermentation for a period of time, the black bean material and the soybean material are made into block-shaped fermented grains with a length, width and height of 18*10*8cm respectively, and ferment until the fermented grains grow white, green or yellow bacteria, and the koji making is completed, and the black bean fermented grains and soybean fermented grains are obtained;

[0037] Preferably, step 2 adopts a koji making process of separately atomizing and inoculating black beans and soybeans, wherein the atomizing spraying amount of Pichia pastoris is 0.1-1.0% (on a black bean dry basis), the static fermentation time is 2-6 hours, the fermentation temperature of the black bean paste is 20-60°C, and the fermentation time is 40-90 hours; the atomizing spraying amount of amyloglucosidase is 0.2-1.5% (on a soybean dry basis), the static fermentation time is 2-6 hours, the fermentation temperature of the soybean paste is 20-60°C, and the fermentation time is 40-90 hours.

[0038] The invention adopts high temperature short time hot air puffing technology to replace the traditional cooking technology, which saves the time of moderate crushing and cooking, and better retains the nutrients of the raw materials. The rich nutrients shorten the time of bean paste making and salt water fermentation, and improves the lengthy sauce making time in the traditional process as a whole.

[0039] Step 3: removing mycelium from the surface of the fermented soybean paste in step 2, crushing the black bean fermented soybean paste and the fermented soybean paste and mixing them to obtain the fermented soybean paste, inoculating Lactobacillus and Pediococcus into the fermented soybean paste, stirring the mixture with salt water, putting the mixture into a fermented soybean paste jar, covering the mixture with gauze, exposing the mixture to the sun under a glass plate that allows sunlight to penetrate, pressing the mixture regularly, and continuing the fermentation to obtain soybean paste;

[0040] The invention selects low-temperature-resistant and efficient bacteria species Lactobacillus and Pediococcus, which can solve the problem of difficult fermentation of bean products under low-temperature environment and improve the fermentation speed and effect.

[0041] Preferably, the mass concentration of the added salt water is 5-30%, and the bacterial species are selected from lactobacillus and pediococcus, which are one or more of plant lactobacillus BP18, pediococcus pentosaceus HS1 and lactobacillus buchneri LP22. If three kinds of bacteria are added, the bacterial species ratio is 1:1:1, and the total inoculation amount is 0.1-2.0%. Wherein, the method of stirring every day is adopted in the first week, and stirring is carried out 2-3 times every seven days from the second week until the fermentation is completed, and the fermentation time is 30-60 days.

[0042] The present invention adopts a step-by-step atomization inoculation koji fermentation method, inoculates black beans and soybeans with Pichia pastoris and amyloglucosidase respectively, and enriches the abundance of metabolites produced by microorganisms in koji making by inoculating corresponding suitable yeasts and enzymes, so that macromolecular nutrients such as acidic proteins and starch macromolecules are fully degraded to avoid antagonism. The method significantly increases the content of amylase, increases the content of biological nutrients such as amino acid nitrogen, sugars and glutamic acid in fermented soybean paste, and can further improve the taste of the composite soybean paste through the nutritional transformation of materials, giving the soybean paste a new flavor and taste, so that the finished soybean paste has a unique taste and a strong sauce aroma.

[0043] In addition, the fermented mash made in steps is fermented with low-temperature resistant mixed bacteria salt water. By adding strains of low-temperature resistant, aroma-producing and aroma-enhancing categories, such as Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22, the soybean paste can be well fermented under low-temperature conditions such as winter, and a mellow, rich, delicate and smooth soybean paste is obtained during the fermentation process. In addition, the added mixed bacteria can increase the microbial richness and metabolic diversity in the soybean paste during the fermentation process. Through the participation of the internal and external environment of the fermentation system itself and the growth and metabolism of microorganisms, multiple metabolic pathways affect the sensory, nutritional and functional characteristics of fermented foods. The composite soybean paste obtained by this method has moderate viscosity, presents a more attractive reddish brown color, is free of impurities, and has good color and shape.

[0044] Step 4: Microwave-assisted pasteurization: The fermented soybean paste in step 3 is subjected to microwave irradiation treatment, and then the soybean paste after microwave irradiation treatment is subjected to pasteurization treatment to obtain a finished composite soybean paste.

[0045] Preferably, the sterilization parameters are: microwave power of 500-900 W, microwave time of 60-120 s; pasteurization temperature of 70-120° C., pasteurization time of 5-25 min.

[0046] The present invention is further explained below in conjunction with specific implementation schemes, but the present invention is not limited thereto.

[0047] Example 1

[0048] The preparation process and application of the composite bean paste include the following steps:

[0049] 1) Pretreatment of raw materials

[0050] The raw materials are composed of the following components: 1800 parts of soybeans, 200 parts of black beans, and 340 parts of food-grade sodium chloride. The black beans and soybeans are screened, cleaned, washed, and crushed appropriately, and then passed through a sieve with a mesh size of 5-20. The hot air puffing is performed, and the technical parameters are that the hot air circulation oven puffing temperature is 150°C and the puffing time is 120s. The black bean material and the soybean material are obtained;

[0051] 2) Step-by-step atomization inoculation and koji making

[0052] The black bean and yellow bean are separately atomized and inoculated to make koji, the Pichia pastoris solution is atomized and sprayed on the black bean material treated in step 1), the spraying amount is 0.75% (on the dry basis of black bean), stirred evenly, and the static fermentation time is 4 hours; the amyloglucosidase solution is atomized and sprayed on the yellow bean material treated in step 1), the spraying amount is 0.75% (on the dry basis of yellow bean), stirred evenly, and the static fermentation time is 4 hours. After the static state is completed, the black bean material and the yellow bean material are respectively made into block-shaped fermented mash with a length, width and height of 18*10*8cm. The fermentation temperature is 40°C, the fermentation time is 60 hours, and the fermentation is completed until the fermented mash grows white, green or yellow bacteria, the koji making is completed, and black bean fermented mash and yellow bean fermented mash are obtained;

[0053] 3) Mixed bacteria salt water fermentation

[0054] The surface of the fermented mash of step 2) is treated to remove mycelium, and the black bean fermented mash and the soybean fermented mash are crushed and mixed to obtain the fermented mash. The strains are selected from Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22, the strain ratio is 1:1:1, and the total inoculation amount is 1.05%. Stir evenly with saline with a mass concentration of 17.5%, put into a sauce jar, cover with gauze, and place under a glass plate that allows sunlight to penetrate. Stir every day in the first week, stir 2-3 times every seven days from the second week, and continue fermentation to obtain soybean paste. The fermentation time is 45 days;

[0055] 4) Microwave assisted pasteurization

[0056] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 700 W, and the microwave time is 90 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 85° C., and the pasteurization time is 15 min to obtain a finished composite soybean paste.

[0057] Example 2

[0058] The preparation process of the composite bean paste comprises the following steps:

[0059] 1) Pretreatment of raw materials

[0060] The raw materials are composed of the following components: 1600 parts of soybeans, 400 parts of black beans, and 480 parts of food-grade sodium chloride. The black beans and soybeans are screened, cleaned, washed, and crushed appropriately, and then passed through a sieve with a mesh size of 5-20. The hot air puffing is performed, and the technical parameters are that the hot air circulation oven puffing temperature is 160°C and the puffing time is 40s. The black bean material and the soybean material are obtained;

[0061] 2) Step-by-step atomization inoculation and koji making

[0062] The black bean and yellow bean are separately atomized and inoculated to make koji, the Pichia pastoris solution is atomized and sprayed on the black bean material treated in step 1), the spraying amount is 0.1% (on the dry basis of black bean), stirred evenly, and the static fermentation time is 6 hours; the amyloglucosidase solution is atomized and sprayed on the yellow bean material treated in step 1), the spraying amount is 0.2% (on the dry basis of yellow bean), stirred evenly, and the static fermentation time is 6 hours. After the static state is completed, the black bean material and the yellow bean material are respectively made into block-shaped fermented mash with a length, width and height of 18*10*8cm. The fermentation temperature is 60°C, the fermentation time is 90 hours, and the fermentation is completed until the fermented mash grows white, green or yellow bacteria, and the koji making is completed to obtain black bean fermented mash and yellow bean fermented mash;

[0063] 3) Mixed bacteria salt water fermentation

[0064] The surface of the fermented mash of step 2) is treated to remove mycelium, and the black bean fermented mash and the soybean fermented mash are crushed and mixed to obtain the fermented mash, wherein the strains are Lactobacillus plantarum BP18 and Lactobacillus buchneri LP22, respectively, the strain ratio is 1:1, and the total inoculation amount is 0.1%. The mixture is evenly stirred with saline having a mass concentration of 5%, put into a sauce jar, covered with gauze, and placed under a glass plate that allows sunlight to pass through, stirred every day in the first week, and stirred 2-3 times every seven days starting from the second week, and fermented continuously to obtain soybean paste, and the fermentation time is 60 days;

[0065] 4) Microwave assisted pasteurization

[0066] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 900 W, and the microwave time is 120 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 70° C., and the pasteurization time is 5 min, to obtain a finished composite soybean paste.

[0067] Example 3

[0068] The preparation process of the composite bean paste comprises the following steps:

[0069] 1) Pretreatment of raw materials

[0070] The raw materials are composed of the following components: 1400 parts of soybeans, 600 parts of black beans, and 200 parts of food-grade sodium chloride. The black beans and soybeans are screened, cleaned, washed, and crushed appropriately, and then passed through a sieve with a mesh size of 5-20. The hot air puffing is performed, and the technical parameters are that the hot air circulation oven puffing temperature is 140°C and the puffing time is 200s to obtain black bean material and soybean material;

[0071] 2) Step-by-step atomization inoculation and koji making

[0072] The black bean and yellow bean are separately atomized and inoculated to make koji, the Pichia pastoris solution is atomized and sprayed on the black bean material treated in step 1), the spraying amount is 1.0% (on the dry basis of black bean), stirred evenly, and the static fermentation time is 2 hours; the amyloglucosidase solution is atomized and sprayed on the yellow bean material treated in step 1), the spraying amount is 1.5% (on the dry basis of yellow bean), stirred evenly, and the static fermentation time is 2 hours. After the static state is completed, the black bean material and the yellow bean material are respectively made into block-shaped fermented mash with a length, width and height of 18*10*8cm. The fermentation temperature is 20°C, the fermentation time is 40 hours, and the fermentation is completed until the fermented mash grows white, green or yellow bacteria, and the koji making is completed to obtain black bean fermented mash and yellow bean fermented mash;

[0073] 3) Mixed bacteria salt water fermentation

[0074] The surface of the fermented mash of step 2) is treated to remove mycelium, and the black bean fermented mash and the soybean fermented mash are crushed and mixed to obtain the fermented mash, the strains of which are Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22, the strain ratio is 1:1, and the inoculation amount is 2.0%. Stir evenly with saline with a mass concentration of 30%, put into a sauce jar, cover with gauze, and place under a glass plate that allows sunlight to penetrate, stir every day in the first week, stir 2-3 times every seven days from the second week, continue fermentation, and obtain soybean paste, and the fermentation time is 30 days;

[0075] 4) Microwave assisted pasteurization

[0076] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 500 W, and the microwave time is 60 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 120° C., and the pasteurization time is 25 min to obtain a finished composite soybean paste.

[0077] Comparative Example 1

[0078] The preparation process of soybean paste comprises the following steps:

[0079] 1) Pretreatment of raw materials

[0080] According to the weight, 2000 parts of soybeans and 340 parts of food-grade sodium chloride. After screening, impurity removal, cleaning, and moderate crushing, the soybeans are sieved with a mesh size of 5-20. The technical parameters of high-temperature short-time hot air puffing are: the hot air circulation oven puffing temperature is 150°C, the puffing time is 120s, and the soybean material is obtained;

[0081] 2) Mist inoculation and koji making

[0082] Spray the amyloglucosidase solution onto the soybean material treated in step 1) at a spraying amount of 0.75% (based on soybean dry basis), stir evenly, and ferment for 4 hours. Make the soybean material into a block of 18*10*8cm in length, width and height. The fermentation temperature is 40°C, and the fermentation time is 60 hours. Ferment until white, green or yellow bacteria grow in the fermented soybean material, and the koji making is completed to obtain the soybean fermented soybean material;

[0083] 3) Mixed bacteria salt water fermentation

[0084] The surface of the fermented soybean paste in step 2) is treated to remove mycelium, and the fermented soybean paste is crushed and mixed to obtain the fermented soybean paste, and the strains are selected from Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22, the strain ratio is 1:1:1, and the total inoculation amount is 1.05%. Stir evenly with saline with a mass concentration of 17.5%, put into a sauce jar, cover with gauze, and place under a glass plate that allows sunlight to penetrate. Stir every day in the first week, stir 2-3 times every seven days from the second week, and continue to ferment to obtain soybean paste. The fermentation time is 45 days;

[0085] 4) Microwave assisted pasteurization

[0086] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 700 W, and the microwave time is 90 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 85° C., and the pasteurization time is 15 min to obtain a finished soybean paste.

[0087] Comparative Example 2

[0088] The preparation process of the composite bean paste comprises the following steps:

[0089] 1) Pretreatment of raw materials

[0090] The raw materials are composed of the following components: 1800 parts of soybeans, 200 parts of black beans, and 340 parts of food-grade sodium chloride. The black beans and soybeans are screened, cleaned, washed, and crushed appropriately, and then passed through a sieve with a mesh size of 5-20. The hot air puffing is performed, and the technical parameters are that the hot air circulation oven puffing temperature is 150°C and the puffing time is 120s. The black bean material and the soybean material are obtained;

[0091] 2) Koji making

[0092] The composite bean material of step 2) is crushed or mashed into a paste to form a block of mashed soy sauce with a length, width and height of 18*10*8cm. The fermentation temperature is 40°C, and the fermentation is completed until white, green or yellow bacteria grow in the mashed soy sauce, and the soy sauce is obtained;

[0093] 3) Mixed bacteria salt water fermentation

[0094] The surface of the fermented soybean paste in step 2) is treated to remove mycelium, and the soybean fermented soybean paste is crushed and mixed to obtain the fermented soybean paste. The strains are selected from Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22, the strain ratio is 1:1:1, and the total inoculation amount is 1.05%. Stir evenly with saline with a mass concentration of 17.5%, put into a sauce jar, cover with gauze, and place under a glass plate that allows sunlight to penetrate. Stir every day in the first week, stir 2-3 times every seven days from the second week, and continue to ferment to obtain soybean paste. The fermentation time is 45 days;

[0095] 4) Microwave assisted pasteurization

[0096] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 700 W, and the microwave time is 90 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 85° C., and the pasteurization time is 15 min to obtain a finished composite soybean paste.

[0097] Comparative Example 3

[0098] The preparation process of the composite bean paste comprises the following steps:

[0099] 1) Pretreatment of raw materials

[0100] The raw materials are composed of the following components: 1800 parts of soybeans, 200 parts of black beans, and 340 parts of food-grade sodium chloride. The black beans and soybeans are screened, cleaned, washed, and crushed appropriately, and then passed through a sieve with a mesh size of 5-20. The hot air puffing is performed, and the technical parameters are that the hot air circulation oven puffing temperature is 150°C and the puffing time is 120s. The black bean material and the soybean material are obtained;

[0101] 2) Step-by-step atomization inoculation and koji making

[0102] The black bean and yellow bean are separately atomized and inoculated to make koji, the Pichia pastoris solution is atomized and sprayed on the black bean material treated in step 1), the spraying amount is 0.75% (on the dry basis of black bean), stirred evenly, and the static fermentation time is 4 hours; the amyloglucosidase solution is atomized and sprayed on the yellow bean material treated in step 1), the spraying amount is 0.75% (on the dry basis of yellow bean), stirred evenly, and the static fermentation time is 4 hours. After the static state is completed, the black bean material and the yellow bean material are respectively made into block-shaped fermented mash with a length, width and height of 18*10*8cm. The fermentation temperature is 40°C, the fermentation time is 60 hours, and the fermentation is completed until the fermented mash grows white, green or yellow bacteria, the koji making is completed, and black bean fermented mash and yellow bean fermented mash are obtained;

[0103] 3) Salt water fermentation

[0104] The surface of the fermented mash in step 2) is treated to remove mycelium, and the fermented mash is crushed and mixed to obtain the fermented mash. The mash is mixed evenly with 25% saline by mass concentration, put into a sauce jar, covered with gauze, and placed under a glass plate that allows sunlight to pass through, stirred regularly during the period, and fermented continuously to obtain soybean paste, and the fermentation time is 60 days;

[0105] 4) Microwave assisted pasteurization

[0106] The fermented soybean paste in step 3) is subjected to microwave irradiation treatment, the microwave power is 700 W, and the microwave time is 90 s; the soybean paste after microwave irradiation is then pasteurized, the pasteurization temperature is 85° C., and the pasteurization time is 15 min to obtain a finished composite soybean paste.

[0107] like Figure 2 As shown, by comparing the composite bean paste obtained in Examples 1-3 with the bean paste obtained in Comparative Examples 1-3, it can be seen that the amino acid nitrogen content of the composite bean paste of Example 1 with 10% black beans added is significantly higher than that of the bean pastes of other Examples and Comparative Examples (the ammonia nitrogen content is more than 75%). In terms of taste, the acidity of Example 1 is significantly reduced, and the taste is mellow; in terms of color, Example 1 shows a reddish brown color, and the sauce color is attractive; in terms of flavor, the unique glycolic acid, 2,3-succinic acid, lactic acid, oleamide, pinitol and other alcohol acids in Example 1 give Example 1 a unique taste.

[0108] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A composite bean paste, It is characterized in that Calculated by weight, it includes: 1400-1800 parts of soybeans, 200-600 parts of black beans, and 200-480 parts of food-grade sodium chloride.

2. A method for preparing the composite bean paste according to claim 1, It is characterized in that The steps include: Step 1: Select soybeans and black beans as raw materials, and pre-treat them to obtain black bean material and soybean material; Step 2: Stepwise atomization inoculation and koji making: spray the Pichia pastoris solution into the black soybean material, stir evenly, and let it stand for fermentation; spray the amyloglucosidase solution into the soybean material, stir evenly, and let it stand for fermentation; After fermentation, the black bean material and the yellow bean material are respectively made into block-shaped fermented grains, and fermented until white, green or yellow bacteria grow in the fermented grains, and the koji making is completed to obtain black bean fermented grains and yellow bean fermented grains; Step 3: mixed bacteria salt water fermentation: the surfaces of the black bean paste and the soybean paste are treated to remove mycelium respectively, the black bean paste and the soybean paste are crushed and mixed to obtain a paste, Lactobacillus and Pediococcus are inoculated into the paste, and the paste is mixed with salt water, put into a sauce jar, covered with gauze, exposed to the sun, pressed regularly, and fermented continuously to obtain soybean paste; Step 4: Microwave-assisted pasteurization: subjecting the soybean paste to microwave irradiation treatment, and then subjecting the soybean paste after microwave irradiation treatment to pasteurization treatment to obtain a finished composite soybean paste.

3. The method for preparing the composite bean paste according to claim 2, It is characterized in that The pretreatment of raw materials in step 1 includes: screening, removing impurities, washing and crushing black beans and yellow beans respectively, and then hot air puffing; wherein the crushed beans are sieved with a mesh size of 5-20 meshes; the hot air puffing is carried out by high temperature and short time hot air puffing, wherein the hot air circulation oven puffing temperature is 140-160°C, and the puffing time is 40-200s.

4. The method for preparing the composite bean paste according to claim 2, It is characterized in that In step 2, the mass percentage of the atomized spraying of the Pichia pastoris solution is 0.1-1.0% based on the dry basis of black beans, the static fermentation time is 2-6 hours, the fermentation temperature of the black bean block mash is 20-60° C., and the fermentation time is 40-90 hours; The atomized spraying amount of the amyloglucosidase solution is 0.2-1.5% based on the dry soybean basis, the static fermentation time is 2-6 hours, the fermentation temperature of the soybean block mash is 20-60° C., and the fermentation time is 40-90 hours.

5. The method for preparing the composite bean paste according to claim 2, It is characterized in that In step 3, Lactobacillus and Pediococcus are inoculated into the mash and stirred evenly with salt water, wherein the mass concentration of the salt water is 5-30%; the Lactobacillus and Pediococcus are one or more of Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22.

6. The method for preparing the composite bean paste according to claim 5, It is characterized in that When Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22 are added, the strain ratio is 1:1:1, and the total inoculation amount is 0.1-2.0%.

7. The method for preparing the composite bean paste according to claim 2, It is characterized in that In step 3, the continuous fermentation process is as follows: stirring is performed every day in the first week, and stirring is performed 2-3 times every seven days starting from the second week until the fermentation is completed. The fermentation time is 30-60 days.

8. The method for preparing the composite bean paste according to claim 2, It is characterized in that In step 4, the pasteurization treatment parameters are: microwave power of 500-900 W, microwave time of 60-120 s; pasteurization temperature of 70-120° C., and pasteurization time of 5-25 min.

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