A soy sauce raw material pretreatment and a soy sauce and a method for preparing the same

Abstract

The application discloses a soy sauce pretreatment raw material and soy sauce and a preparation method thereof, and relates to the processing field of condiments. The soy sauce pretreatment raw material comprises the following preparation steps: sequentially immersing soybeans in a first immersion liquid, a second immersion liquid and a third immersion liquid with gradient temperature rise and gradient osmotic pressure rise; then, the filtered and immersed soybeans are sequentially subjected to low-temperature immersion and rapid aging treatment, the temperature is controlled to be 93-97 DEG C during the low-temperature immersion, and the temperature is controlled to be 110-150 DEG C during the rapid aging, so that the soy sauce pretreatment raw material is prepared. The application induces the water absorption and swelling of the soybeans through the gradient osmotic pressure and the gradient temperature rise, changes and improves the intercellular space, activates the endogenous flavor enzyme system, and simultaneously performs segmented cooking treatment at different temperatures, so that the generation and retention of umami substances are improved, the production of bitter substances is reduced, the flavor and taste of the soy sauce are improved, and the contradiction and problem between the traditional high temperature and the flavor retention are broken through.

Description

Technical Field

[0001] This invention relates to the field of condiment processing, and more particularly to a soy sauce pretreatment raw material, soy sauce, and a method for preparing the same. Background Technology

[0002] Currently, the pretreatment of soybean raw materials for soy sauce production generally suffers from technical bottlenecks, including the inefficiency of traditional hydration processes and the deterioration of quality caused by excessive high-temperature cooking. Traditional hydration processes rely on conventional water soaking, which involves prolonged natural osmosis. This results in a loss of up to 28% of water-soluble sugars such as glucose and maltose with the soaking water. Furthermore, due to the lack of osmotic pressure regulation, the intercellular space after soaking is only 0.5-1.0 μm, and the activation rate of endogenous β-amylase and protease is less than 30%, severely impacting subsequent enzymatic hydrolysis efficiency. High-temperature cooking uses modern steam technology (120-150 ℃ / 15 min), which can quickly cook the material and kill bacteria. However, the high temperature also promotes excessive Maillard reactions, resulting in 5-hydroxymethylfurfural (HMF) content generally exceeding 200 μg / kg, exceeding the national standard GB5009.285-2021 limit of ≤150 μg / kg. Simultaneously, it leads to a loss of over 40% of umami amino acids such as glutamic acid and aspartic acid, severely affecting the flavor and quality of soy sauce. Summary of the Invention

[0003] This invention provides a soy sauce pretreatment raw material, soy sauce, and a method for preparing the same. By inducing soybeans to absorb water and change the intercellular spaces through gradient osmotic pressure and temperature, the endogenous flavor enzyme system is activated. At the same time, segmented heating and cooking treatment is carried out to improve the generation and retention of umami substances, reduce the production of burnt and bitter substances, and enhance the flavor and taste of soy sauce.

[0004] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing soy sauce pretreatment raw materials, comprising the following steps:

[0005] (1) Soak soybeans in a first soaking solution at a temperature of 20-30 ℃, the first soaking solution containing 2wt%-4wt% chloride by mass, for 1.5-2.5 h, then soak them in a second soaking solution at a temperature of 40-50 ℃, the second soaking solution containing 4wt%-6wt% chloride by mass, for 1-2 h; then soak them in a third soaking solution at a temperature of 55-65 ℃, the third soaking solution containing 6wt%-8wt% chloride by mass, for 0.5-1.5 h;

[0006] (2) Soaked and filtered soybeans are subjected to low-temperature cooking and rapid maturation treatment in sequence. The temperature is controlled at 93-97 ℃ during low-temperature cooking and 110-150 ℃ during rapid maturation to prepare soy sauce pretreatment raw materials.

[0007] This application involves soaking soybeans in saline solutions with different osmotic pressures to deesterify pectin, thereby degrading pectin and improving the mass transfer efficiency of the subsequent cooking stage, reducing the required cooking time. By inducing soybeans to absorb water and swell through gradient osmotic pressure and gradient temperature, the activity of endogenous β-amylase in soybeans is activated and enhanced, the intercellular space is expanded, and the molecular weight of pectin is reduced, increasing the reaction sites for subsequent cooking. Subsequently, through staged low-temperature soaking and rapid maturation treatment, the material is fully pre-denatured under the condition of controlling the temperature below 100 ℃, which can inhibit the formation of bitter substances such as hydroxymethylfurfural and reduce the loss of umami amino acids. Then, the rapid maturation stage is carried out at the condition of controlling the temperature above 100 ℃ for complete maturation, which can rapidly generate roasted aroma substances such as furans (maltol) and pyrazines (2,5-dimethylpyrazine), and directionally regulate the Maillard reaction pathway, so that the prepared soy sauce can simultaneously maximize the retention of umami substances, reduce the production of bitter substances, and increase the formation of aroma precursors, breaking through the contradiction between high temperature and flavor preservation in traditional processes.

[0008] Secondly, traditional processes require soybean raw materials to be soaked in water for a long time, with a soaking time of more than 14 hours to soften the material. However, this application uses gradient osmotic pressure and temperature to soak soybeans, with a total processing time of no more than 6 hours, shortening the total process time and increasing the dissolution of flavor precursors.

[0009] As a preferred embodiment, the chlorides in the first soaking solution, the second soaking solution, and the third soaking solution are each independent and are at least one of NaCl, KCl, MgCl2, and CaCl2.

[0010] As a preferred embodiment, the chloride in the first soaking solution, the second soaking solution, and the third soaking solution is NaCl.

[0011] When soybean raw materials are soaked in NaCl aqueous solution under gradient osmotic pressure, the enthalpy value of the soybean raw materials increases with the penetration of NaCl, forming a starch-lipid complex. NaCl soaking can inhibit the destruction of the starch crystallization region of the raw materials and improve the crystallization characteristics of starch. As the NaCl solution concentration increases, the particle density decreases, the interparticle gaps become larger, the material surface becomes rougher, the water absorption rate and swelling rate increase, the hardness of the raw materials decreases, the material softens, and flavor precursor substances gradually soften the cell structure, which can activate endogenous enzymes such as glutaminase, making it easier to dissolve flavor precursors such as water-soluble sugars and free amino acids, and the water absorption efficiency is improved by at least 40% compared with the traditional water soaking effect.

[0012] As a preferred embodiment, the mass fraction of the first soaking solution is 2.5wt%-3.5wt%.

[0013] As a preferred embodiment, the mass fraction of the second soaking solution is 4.5wt%-5.5wt%.

[0014] As a preferred embodiment, the mass fraction of the third soaking solution is 6.5wt%-7.5wt%.

[0015] This application controls the concentration of the soybean soaking solution within the above-mentioned range, which can achieve gradient adjustment of the osmotic pressure of the soaking solution. This allows the osmotic pressure of the soaking solution to fully induce the expansion of the soybean raw material, improve the water absorption and expansion efficiency, increase the intercellular space, promote the dissolution of flavor precursor substances, and ultimately increase the content of umami and aroma substances in the prepared soy sauce, thereby enhancing the flavor of the soy sauce.

[0016] As a preferred embodiment, the temperature of the first soaking solution is 22-28 ℃.

[0017] As a preferred embodiment, the temperature of the second soaking solution is 42-47 ℃.

[0018] As a preferred embodiment, the temperature of the third soaking solution is 58-63 ℃.

[0019] As a preferred option, in step (2), before soaking and filtering soybeans are subjected to low-temperature cooking, they are pre-treated with wet steaming, and the temperature is controlled at 88-92 ℃ during wet steaming.

[0020] This application pre-treatment of soaked soybean raw materials with wet steaming before low-temperature cooking can achieve rapid heating and sterilization, resulting in uniform temperature in all parts of the material. This allows the material structure to soften quickly during the subsequent low-temperature cooking stage. The low temperature and short cooking time can inhibit the formation of bitter substances such as hydroxymethylfurfural and reduce the loss of umami amino acids.

[0021] As a preferred option, in step (2), after the soybeans are soaked and cooked at low temperature and before they are rapidly cooked, they are pre-treated by dry steaming, and the temperature is controlled at 98-102 ℃ during dry steaming.

[0022] After the soybean raw material is softened by low-temperature soaking and cooking, it is pre-treated by dry steaming, which can provide a uniform preheating effect, so that the temperature difference between different parts of the material is less than 5 ℃. This facilitates the subsequent rapid cooking stage, which can fully cook the material in a high-temperature environment in a short time. It can quickly generate roasting aroma substances such as furans (maltol) and pyrazines (2,5-dimethylpyrazine), and avoid excessive Maillard reaction to generate burnt bitter substances.

[0023] As a preferred option, in step (2), the low-temperature soaking treatment time is 10-20 min.

[0024] As a preferred option, in step (2), the rapid ripening time is 2-4 min.

[0025] As a preferred option, in step (2), hot water accounting for 100%-106% of the material mass is added during rapid maturation, and the temperature of the hot water is 70-90 ℃.

[0026] As a preferred option, in step (2), the wet steaming time is 2.5-3.5 min.

[0027] As a preferred option, in step (2), the dry steaming time is 2-8 min.

[0028] To solve the above-mentioned technical problems, the second objective of this invention is to provide a soy sauce pretreatment raw material prepared using the aforementioned method for preparing soy sauce pretreatment raw materials.

[0029] To address the aforementioned technical problems, a third objective of this invention is to provide a method for preparing soy sauce, comprising the following steps:

[0030] S1. Mix roasted wheat and soy sauce pretreatment raw materials evenly, inoculate the mixture with Aspergillus oryzae starter, and make koji to obtain koji material;

[0031] S2. The koji material is evenly mixed with salt water for high-salt dilute state fermentation. After fermentation, the mash filtrate after pressing and filtering is collected and heated to obtain soy sauce.

[0032] As a preferred embodiment, the mass ratio of the roasted wheat and soy sauce pretreatment raw materials is (5-7):(3-5).

[0033] As a preferred embodiment, in step S1, the Aspergillus oryzae seed koji accounts for 0.3wt%-0.5wt% of the mass fraction of the roasted wheat.

[0034] As a preferred embodiment, in step S1, the humidity is controlled at 90%-95%, the koji-making temperature at 28-35 ℃, and the koji-making time at 30-50 h.

[0035] As a preferred embodiment, in step S2, the mass ratio of the koji material to the brine is 1:(1.3-2.4).

[0036] As a preferred embodiment, in step S2, the mass fraction concentration of NaCl in the saline solution is 19wt%-23wt%.

[0037] As a preferred option, in step S2, the fermentation temperature is 31-39 ℃.

[0038] As a preferred option, in step S2, the fermentation cycle is 45-90 days.

[0039] As a preferred embodiment, in step S2, the heating temperature of the fermented soybean paste filtrate is 60-70 ℃, and the heating time is 3-5 h.

[0040] To solve the above-mentioned technical problems, the fourth objective of this invention is to provide a soy sauce prepared using the aforementioned soy sauce preparation method.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. In this application, soybeans are soaked in saline solutions with different osmotic pressures. The expansion of soybeans is induced by gradient osmotic pressure and gradient temperature. Chloride penetrates into the soybean raw material and can form a starch-lipid complex. Chloride can improve the crystallization characteristics of starch, soften cell structure, activate and enhance the enzyme activity of endogenous β-amylase in soybeans, making it easier to dissolve flavor preconditions. The water absorption rate is increased by at least 40% compared with the traditional method. The intercellular space is expanded, which increases the reaction sites in subsequent cooking and promotes the generation of aroma substances.

[0043] 2. This application employs a phased low-temperature soaking and rapid maturation process. In the low-temperature soaking stage below 100 ℃, the material is fully pre-denatured, which can inhibit the formation of burnt and bitter substances such as hydroxymethylfurfural and reduce the loss of umami amino acids. Subsequently, in the rapid maturation stage above 100 ℃, the material is fully matured, which can rapidly generate roasted aroma substances such as furans (maltol) and pyrazines (2,5-dimethylpyrazine). This process can directionally regulate the Maillard reaction pathway, thereby enhancing the flavor of the prepared soy sauce and reducing burnt and bitter off-flavor substances, thus overcoming the contradiction between high temperature and flavor preservation in traditional processes. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0046] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0047] As used in this article:

[0048] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0049] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0050] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0051] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.

[0052] Example 1

[0053] A method for preparing a soy sauce pretreatment raw material includes the following steps:

[0054] (1) Weigh 100 g of Northeast soybeans (protein content 42%, moisture content 12%) and soak them in a first soaking solution at 25 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the first soaking solution is 3wt%, the osmotic pressure is 0.85 MPa, and the soaking time is 2 h. Then soak the soybeans in a second soaking solution at 45 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the second soaking solution is 5wt%, the osmotic pressure is 1.2 MPa, and the soaking time is 1.5 h. Then soak the soybeans in a third soaking solution at 60 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the third soaking solution is 7wt%, the osmotic pressure is 1.8 MPa, and the soaking time is 1 h.

[0055] (2) After soaking and filtering, the soybeans were subjected to wet steaming and low-temperature soaking in water. After filtration, they were subjected to dry steaming and rapid cooking. During wet steaming, the temperature was controlled at 90 ℃ and the processing time was 3 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature was controlled at 95 ℃ and the processing time was 15 min to soften the material structure and ensure that the moisture content of the material exceeded 65%. During dry steaming, the temperature was controlled at 100 ℃ and the processing time was 5 min to ensure uniform preheating and ensure that the temperature difference of the material was <5 ℃. During rapid cooking, hot water at 80 ℃ and accounting for 105% of the material mass was added, and the cooking temperature was controlled at 130 ℃ and the pressure was controlled at 0.25 MPa for 3 min to carry out the Maillard reaction and prepare the soy sauce pretreatment raw material.

[0056] Example 2

[0057] A method for preparing a soy sauce pretreatment raw material includes the following steps:

[0058] (1) Weigh 100 g of Northeast soybeans (protein content 42%, moisture content 12%) and soak them in a first soaking solution at 22 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the first soaking solution is 2.5 wt%, and the soaking time is 2.5 h. Then soak the soybeans in a second soaking solution at 42 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the second soaking solution is 4.5 wt%, and the soaking time is 2 h. Then soak the soybeans in a third soaking solution at 58 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the third soaking solution is 6.5 wt%, and the soaking time is 1.5 h.

[0059] (2) After soaking and filtering, the soybeans were subjected to wet steaming and low-temperature soaking with water in sequence. After filtration, they were subjected to dry steaming and rapid cooking in sequence. During wet steaming, the temperature was controlled at 88 ℃ and the processing time was 3.5 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature was controlled at 93 ℃ and the processing time was 20 min to soften the material structure and ensure that the moisture content of the material exceeded 65%. During dry steaming, the temperature was controlled at 98 ℃ and the processing time was 8 min to ensure uniform preheating and ensure that the temperature difference of the material was <5 ℃. During rapid cooking, hot water at 80 ℃ and accounting for 105% of the material mass was added, and the cooking temperature was controlled at 110 ℃. The pressure was controlled at 0.35 MPa and the processing time was 4 min to carry out the Maillard reaction and prepare the soy sauce pretreatment raw material.

[0060] Example 3

[0061] A method for preparing a soy sauce pretreatment raw material includes the following steps:

[0062] (1) Weigh 100 g of Northeast soybeans (protein content 42%, moisture content 12%) and soak them in the first soaking solution at 28 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the first soaking solution is 3.5 wt%, and the soaking time is 1.5 h. Then soak the soybeans in the second soaking solution at 47 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the second soaking solution is 5.5 wt%, and the soaking time is 1 h. Then soak the soybeans in the third soaking solution at 63 ℃ at a mass ratio of 1:1. The mass fraction of NaCl in the third soaking solution is 7.5 wt%, and the soaking time is 0.5 h.

[0063] (2) After soaking and filtering, the soybeans were subjected to wet steaming and low-temperature soaking with water in sequence. After filtration, they were subjected to dry steaming and rapid cooking in sequence. During wet steaming, the temperature was controlled at 92 ℃ and the processing time was 2.5 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature was controlled at 97 ℃ and the processing time was 10 min to soften the material structure and ensure that the moisture content of the material exceeded 65%. During dry steaming, the temperature was controlled at 102 ℃ and the processing time was 2 min to ensure uniform preheating and ensure that the temperature difference of the material was <5 ℃. During rapid cooking, hot water at 80 ℃ and accounting for 105% of the material mass was added, and the cooking temperature was controlled at 150 ℃ and the pressure was controlled at 0.18 MPa for 2 min to carry out the Maillard reaction and prepare the soy sauce pretreatment raw material.

[0064] Example 4

[0065] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42%, moisture content 12%) are weighed and soaked in a first soaking solution at 25 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the first soaking solution is 2wt%, and the soaking time is 2 h. Then, the soybeans are soaked in a second soaking solution at 45 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the second soaking solution is 4wt%, and the soaking time is 1.5 h. Then, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the third soaking solution is 6wt%, and the soaking time is 1 h.

[0066] Example 5

[0067] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42%, moisture content 12%) are weighed and soaked in a first soaking solution at 25 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the first soaking solution is 4wt%, and the soaking time is 2 h. Then, the soybeans are soaked in a second soaking solution at 45 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the second soaking solution is 6wt%, and the soaking time is 1.5 h. Then, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the third soaking solution is 8wt%, and the soaking time is 1 h.

[0068] Example 6

[0069] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (2), after soaking and filtering, the soybeans are soaked and filtered, then water is added and the mixture is subjected to low-temperature cooking. After filtration, the mixture is subjected to rapid maturation treatment. During low-temperature cooking, the temperature is controlled at 95 ℃ and the treatment time is 15 min. By softening the material structure, the water content of the material can be guaranteed to exceed 65%. During rapid maturation, hot water at 80 ℃ and accounting for 105% of the material mass is added, the maturation temperature is controlled at 130 ℃, the pressure is controlled at 0.25 MPa, and the treatment time is 3 min. The Maillard reaction is carried out to prepare the soy sauce pretreatment raw materials.

[0070] Example 7

[0071] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (2), the soaked and filtered soybeans are sequentially subjected to wet steaming and low-temperature soaking with water, and after filtration, they are sequentially subjected to dry steaming and rapid maturation. During wet steaming, the temperature is controlled at 90 ℃ and the processing time is 3 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature is controlled at 95 ℃ and the processing time is 15 min to soften the material structure and ensure that the material moisture content exceeds 65%. During dry steaming, the temperature is controlled at 100 ℃ and the processing time is 5 min to perform uniform preheating to ensure that the material temperature difference is <5 ℃. During rapid maturation, hot water at 80 ℃ and accounting for 105% of the material mass is added, the maturation temperature is controlled at 150 ℃, the pressure is controlled at 0.18 MPa, and the processing time is 3 min to carry out Maillard reaction and prepare soy sauce pretreatment raw materials.

[0072] Example 8

[0073] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (2), the soaked and filtered soybeans are sequentially subjected to wet steaming and low-temperature soaking with water, and after filtration, they are sequentially subjected to dry steaming and rapid maturation. During wet steaming, the temperature is controlled at 90 ℃ and the processing time is 3 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature is controlled at 95 ℃ and the processing time is 15 min to soften the material structure and ensure that the material moisture content exceeds 65%. During dry steaming, the temperature is controlled at 100 ℃ and the processing time is 5 min to perform uniform preheating to ensure that the material temperature difference is <5 ℃. During rapid maturation, hot water at 80 ℃ and accounting for 105% of the material mass is added, the maturation temperature is controlled at 110 ℃, the pressure is controlled at 0.35 MPa, and the processing time is 3 min to carry out Maillard reaction and prepare soy sauce pretreatment raw materials.

[0074] Example 9

[0075] A method for preparing raw materials for soy sauce pretreatment is provided. The steps, reagents, equipment, and process parameters used in each step are the same as those in Example 1. The difference is that in step (1), 100 g of Northeast soybeans (protein content 42%, moisture content 12%) are weighed and soaked in a second soaking solution at 45 ℃ at a mass ratio of 1:1. The mass fraction concentration of NaCl in the second soaking solution is 5wt%, the osmotic pressure is 1.2 MPa, and the soaking time is 2.5 h. Subsequently, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1. The mass fraction concentration of NaCl in the third soaking solution is 7wt%, the osmotic pressure is 1.8 MPa, and the soaking time is 2 h.

[0076] Example 10

[0077] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42% and moisture content 12%) are weighed and soaked in a first soaking solution at 25 ℃ at a mass ratio of 1:1. The mass fraction concentration of NaCl in the first soaking solution is 3wt%, the osmotic pressure is 0.85 MPa, and the soaking time is 3 h. Subsequently, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1. The mass fraction concentration of NaCl in the third soaking solution is 7wt%, the osmotic pressure is 1.8 MPa, and the soaking time is 1.5 h.

[0078] Comparative Example 1

[0079] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (2), the soaked and filtered soybeans are steamed and hot water at 80 ℃ and accounting for 105% of the material mass is added, the steaming temperature is 120 ℃, the steaming pressure is 0.15 MPa, and the steaming time is 20 min, soy sauce pretreatment raw materials are prepared.

[0080] Comparative Example 2

[0081] A method for preparing soy sauce pretreatment raw materials, the steps and reagents, equipment and process parameters used in each step are the same as in Example 1. The difference is that in step (1), 100 g of Northeast soybeans (protein content 42% and moisture content 12%) are weighed and soaked in water at a mass ratio of 1:1. The soaking temperature is 25 ℃ and the soaking time is 18 h.

[0082] Comparative Example 3

[0083] A method for preparing raw materials for soy sauce pretreatment, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (1), 100 g of Northeast soybeans (protein content 42% and moisture content 12%) are weighed and soaked in brine at a temperature of 60 °C at a mass ratio of 1:1. The mass fraction concentration of NaCl in the brine is 7wt%, and the soaking time is 4.5 h.

[0084] Comparative Example 4

[0085] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42% and moisture content 12%) are weighed and soaked in water at 25 ℃ for 2 h at a material-to-liquid ratio of 1:1. Then, the soybeans are soaked in water at 45 ℃ for 1.5 h at a material-to-liquid ratio of 1:1. Finally, the soybeans are soaked in water at 60 ℃ for 1 h at a material-to-liquid ratio of 1:1.

[0086] Comparative Example 5

[0087] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (2), the soaked and filtered soybeans are sequentially subjected to wet steaming and low-temperature soaking with water, and after filtration, they are sequentially subjected to dry steaming and rapid maturation. During wet steaming, the temperature is controlled at 90 ℃ and the processing time is 3 min to achieve rapid heating and sterilization. During low-temperature soaking, the temperature is controlled at 95 ℃ and the processing time is 15 min to soften the material structure and ensure that the material moisture content exceeds 65%. During dry steaming, the temperature is controlled at 100 ℃ and the processing time is 5 min to perform uniform preheating to ensure that the material temperature difference is <5 ℃. During rapid maturation, hot water at 80 ℃ and accounting for 105% of the material mass is added, the maturation temperature is controlled at 165 ℃, the pressure is controlled at 0.25 MPa, and the processing time is 3 min to carry out the Maillard reaction and prepare the soy sauce pretreatment raw materials.

[0088] Comparative Example 6

[0089] A method for preparing a soy sauce pretreatment raw material includes the following steps:

[0090] (1) Weigh 100 g of Northeast soybeans (protein content 42%, moisture content 12%), add water at a material-to-liquid ratio of 1:1, soak at 25 ℃ for 18 h;

[0091] (2) Soaked and filtered soybeans are steamed and cooked. Hot water at 80 ℃ and accounting for 105% of the material mass is added. The cooking temperature is 120 ℃, the cooking pressure is 0.15 MPa, and the cooking time is 20 min to prepare soy sauce pretreatment raw materials.

[0092] Comparative Example 7

[0093] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42%, moisture content 12%) are weighed and soaked in a first soaking solution at 25 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the first soaking solution is 1wt%, and the soaking time is 2 h. Then, the soybeans are soaked in a second soaking solution at 45 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the second soaking solution is 3wt%, and the soaking time is 1.5 h. Then, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the third soaking solution is 5wt%, and the soaking time is 1 h.

[0094] Comparative Example 8

[0095] A method for preparing soy sauce pretreatment raw materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (1), 100 g of Northeast soybeans (protein content 42%, moisture content 12%) are weighed and soaked in a first soaking solution at 25 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the first soaking solution is 5wt%, and the soaking time is 2 h. Then, the soybeans are soaked in a second soaking solution at 45 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the second soaking solution is 7wt%, and the soaking time is 1.5 h. Then, the soybeans are soaked in a third soaking solution at 60 ℃ at a mass ratio of 1:1, the mass fraction concentration of NaCl in the third soaking solution is 9wt%, and the soaking time is 1 h.

[0096] The soy sauce pretreatment raw materials prepared in Examples 1-10 and Comparative Examples 1-8 above are used to prepare soy sauce, including the following steps:

[0097] (1) Roasted wheat was mixed into the cooled soy sauce pretreatment raw material at a mass ratio of 6:4, and 0.3wt% of Aspergillus oryzae koji was added at the same time. The mixture was loosely spread into a disc, the initial relative humidity was controlled at 95%, the koji-making temperature was 32 ℃, and the koji-making material was obtained after 38 h.

[0098] (2) Mix the koji material with a 20wt% brine solution for high-salt dilute fermentation. The mass ratio of koji material to brine solution is 1:2. The fermentation temperature is 36 ℃ and the fermentation cycle is 60 days. Collect the filtrate of the mash after pressing and filtering, and heat it at 65 ℃ for 4 h to obtain soy sauce.

[0099] Performance testing

[0100] 1. After soaking in step (1) of the examples and comparative examples, the intercellular spaces between the cell walls and cell membranes of the cotyledon cells were observed and measured under a microscope. At the same time, 25 g of the soybean sample after soaking in step (1) was taken, and water was added at 4 times the weight of the material for grinding and pulping. The soybean extract was filtered to obtain the soybean extract. The water-soluble sugar content (kit method), osmotic pressure, total free amino acid, β-amylase, and pectin molecular weight of the soybean were measured. Three samples were taken for each group, and the average value was taken. The test results are shown in Table 1 below.

[0101] Table 1 - Performance test results of soybeans after soaking in step (1) of the embodiments and comparative examples of this application

[0102]

[0103]

[0104] 2. After the soy sauce pretreatment raw materials of the examples and comparative examples were used for koji fermentation to prepare soy sauce, a sensory evaluation was conducted by trained professionals. The evaluation was carried out according to the standards in Table 2 below, and the sensory score was calculated according to the following formula: Sensory score = (Aroma score + Taste score + Appearance score) / 3. The sensory score results are shown in Table 3 below.

[0105] Table 2 - Sensory Evaluation Criteria for Soy Sauce

[0106]

[0107] 3. The soy sauce pretreatment raw materials from the examples and comparative examples were used to prepare soy sauce samples after fermentation. The contents of HEMF, pyrazines, and HMF were determined. The HMF content was tested according to GB5009.285-2021 standard. The retention rates of proline, glycine, alanine, and glutamic acid were also tested. The amino acid content in soybean raw materials that had not undergone any heat treatment in step (2) and had completed hydration in step (1) was used as the baseline (i.e., 100%). The calculation formula was: Amino acid retention rate (%) = (Amino acid content in the soy sauce pretreatment raw material sample after heat treatment / Amino acid content in the baseline sample) × 100%. The test results are shown in Table 3 below.

[0108] Table 3 - Performance test results of soy sauce prepared from pretreated raw materials in the embodiments and comparative examples of this application.

[0109]

[0110]

[0111] As shown in Tables 1-2, in Examples 1-3 of this application, soybeans were soaked in saline solutions with different osmotic pressures to deesterify pectin, thereby degrading pectin to reduce its molecular weight and improve the mass transfer efficiency in the subsequent cooking stage. By inducing soybeans to absorb water and swell through gradient osmotic pressure and gradient temperature, the enzyme activity of endogenous β-amylase in soybeans was activated and enhanced, the intercellular space was expanded, and the amount of water-soluble sugars dissolved and the total amount of free amino acids increased, which increased the number of reaction sites in the subsequent cooking stage. Subsequently, through staged wet steaming, low-temperature soaking, dry steaming and rapid ripening treatment, the formation of burnt bitter substances such as hydroxymethylfurfural could be inhibited, the loss of umami amino acids could be reduced, and a large amount of roasting aroma substances such as furans (maltol) and pyrazines (2,5-dimethylpyrazine) could be generated, thereby directionally regulating the Maillard reaction pathway and improving the flavor of soy sauce.

[0112] Compared to Example 1, Comparative Examples 1 and 6 both used traditional high-temperature cooking processes. The prolonged high-temperature environment can lead to excessive Maillard reaction, increasing the formation of bitter-tasting substances (HMF). Furthermore, high-temperature cooking cannot effectively preserve the content of umami amino acids, and the content of aroma compounds such as furans and pyrazines decreases, resulting in a reduction in the flavor and taste of the prepared soy sauce, and the presence of a bitter-tasting off-flavor.

[0113] Compared to Example 1, Comparative Examples 2 and 6 both used traditional methods to soak soybeans in water for extended periods. This resulted in low soybean absorption and expansion efficiency, low pectin degradation efficiency, small intercellular spaces, and an inability to effectively activate endogenous enzymes. Consequently, the total amount of plant β-amylase and amino acids was low, leading to a reduction in the content of aroma and flavor compounds produced during subsequent staged cooking, resulting in insufficient flavor in the soy sauce. Comparative Example 4 used water to soak soybeans for a short time. After soaking, the intercellular spaces of the soybeans were smaller, leading to a reduction in reaction sites during subsequent staged cooking, and a decrease in the content of amino acids and aroma compounds.

[0114] Compared to Example 1, Comparative Example 3 used a single osmotic pressure saline solution to soak soybeans. Because it did not employ gradient osmotic pressure and temperature treatment, it lacked a gradual cell adaptation process. Changes in cell wall and cell membrane structure require adaptation to changes in osmotic pressure. The gradient hydration method in this application, using a gradual increase in osmotic pressure, allows cells to slowly and gently absorb water and swell, improving pectin degradation efficiency and resulting in orderly expansion of intercellular spaces. In contrast, the single hypertonic environment in Comparative Example 3 forces cells to rapidly lose water (plasmolysis) and then slowly absorb water again. This process is abrupt and inefficient, easily leading to cell structural damage and failing to achieve optimal swelling. Furthermore, different endogenous enzymes require different temperatures and osmotic pressures to be effectively activated. The dual gradient of temperature and salinity in gradient hydration provides a suitable environment for the sequential activation of various endogenous enzymes (such as β-amylase and glutaminase). The single osmotic pressure condition in Comparative Example 3 cannot achieve a synergistic activation effect of endogenous enzymes, resulting in a decrease in the amount of water-soluble sugars dissolved in soybeans and the content of plant β-amylase. Consequently, the aroma compounds in the prepared soy sauce are reduced, resulting in insufficient soy sauce flavor.

[0115] Compared to Example 1, Comparative Example 5 had an excessively high temperature during the rapid ripening stage of soybeans, resulting in excessive Maillard reaction, excessive decomposition of flavor compounds, and increased formation of burnt and bitter substances. This led to an increase in the HMF content of the prepared soy sauce, while the content of furans, pyrazines, and amino acids decreased, resulting in a poorer soy sauce flavor.

[0116] Compared to Example 1, in Comparative Example 7, the NaCl concentration in the first, second, and third soaking solutions used for gradient osmotic pressure soaking of soybeans was too low, which made it difficult for osmotic pressure to effectively induce soybeans to absorb water and swell. As a result, the intercellular spaces were smaller, and the amount of water-soluble sugars dissolved and the content of free amino acids decreased, affecting the subsequent formation of flavor substances in soy sauce.

[0117] Compared to Example 1, in Comparative Example 8, the NaCl concentration in the first, second, and third soaking solutions used for gradient osmotic pressure soaking of soybeans was excessively high. This high initial osmotic pressure led to a rapid and significant loss of intracellular water, causing irreversible cell collapse and damage. This negatively impacted subsequent water absorption capacity and the physical structure of the matrix, hindering the uniformity of subsequent reactions. Furthermore, the high salt concentration inhibited the activity of various enzymes, affecting the efficiency of protein and starch hydrolysis throughout the brewing process. Excessive sodium ions directly entering the raw materials not only initially inhibited the growth and metabolism of microorganisms during subsequent koji-making and fermentation stages but also potentially introduced a sharp salty or even bitter taste, affecting the final flavor balance and smoothness of the soy sauce.

[0118] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing a soy sauce pretreatment raw material, characterized in that, Includes the following steps: (1) Soak soybeans in a first soaking solution at a temperature of 20-30 ℃, the first soaking solution containing 2.5wt%-3.5wt% chloride by mass, for 1.5-2.5 h, then soak them in a second soaking solution at a temperature of 40-50 ℃, the second soaking solution containing 4.5wt%-5.5wt% chloride by mass, for 1-2 h; then soak them in a third soaking solution at a temperature of 55-65 ℃, the third soaking solution containing 6.5wt%-7.5wt% chloride by mass, for 0.5-1.5 h, wherein the chloride in the first, second and third soaking solutions is NaCl; (2) After soaking and filtering, the soybeans are subjected to low-temperature cooking and rapid cooking in sequence. The temperature is controlled at 93-97 ℃ and the cooking time is 10-20 min. The temperature is controlled at 110-150 ℃ and the cooking time is 2-4 min. Soy sauce pretreatment raw materials are prepared.

2. The method for preparing soy sauce pretreatment raw materials as described in claim 1, characterized in that, The temperature of the first soaking solution is 22-28 ℃; And / or, the temperature of the second soaking solution is 42-47 ℃; And / or, the temperature of the third soaking solution is 58-63 ℃.

3. The method for preparing soy sauce pretreatment raw materials as described in claim 1, characterized in that, In step (2), before the soaked and filtered soybeans are boiled at low temperature, they are pre-treated with wet steaming, and the temperature is controlled at 88-92 ℃ during wet steaming. And / or, in step (2), after the soybeans are soaked at low temperature and before they are rapidly cooked, they are pre-treated by dry steaming, with the temperature controlled at 98-102 ℃ during dry steaming.

4. The method for preparing soy sauce pretreatment raw materials as described in claim 3, characterized in that, In step (2), the wet steaming treatment time is 2.5-3.5 min; And / or, in step (2), the dry steaming time is 2-8 min.

5. A soy sauce pretreatment raw material prepared using the preparation method of soy sauce pretreatment raw material as described in any one of claims 1-4.

6. A method for preparing soy sauce, characterized in that, The method of using the soy sauce pretreatment raw material as described in claim 5 includes the following steps: S1. Mix roasted wheat and soy sauce pretreatment raw materials evenly, inoculate the mixture with Aspergillus oryzae starter, and make koji to obtain koji material; S2. The koji material is evenly mixed with salt water for high-salt dilute state fermentation. After fermentation, the mash filtrate after pressing and filtering is collected and heated to obtain soy sauce.

7. The method for preparing soy sauce as described in claim 6, characterized in that, In step S1, the mass ratio of the roasted wheat and the soy sauce pretreatment raw material is (5-7):(3-5); And / or, in step S1, the Aspergillus oryzae koji comprises 0.3wt%-0.5wt% of the roasted wheat by mass. And / or, in step S1, the humidity is controlled at 90%-95%, the koji-making temperature at 28-35 ℃, and the koji-making time at 30-50 h; And / or, in step S2, the mass ratio of the koji material to the brine is 1:(1.3-2.4). And / or, in step S2, the mass fraction concentration of NaCl in the saline solution is 19wt%-23wt%; And / or, in step S2, the fermentation temperature is 31-39 ℃; And / or, in step S2, the fermentation cycle is 45-90 days; And / or, in step S2, the heating temperature of the fermented sauce filtrate is 60-70 ℃, and the heating time is 3-5 h.

8. A soy sauce prepared using the soy sauce preparation method as described in claim 6 or 7.

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