Salt-free soy sauce and preparation method thereof

Abstract

The present invention relates to a kind of salt-free soy sauce and preparation method thereof, belong to the technical field of condiment preparation, and the preparation method comprises: step 1, raw material processing and koji making, obtain koji material; step 2, salt-free fermentation, the koji material is mixed with alcohol water as sauce mash, and the sauce mash is fermented for 1-6 months; step 3, the fermented sauce mash is squeezed to extract juice, and high-alcohol soy sauce is obtained; step 4, the high-alcohol soy sauce is distilled to reduce the content of alcohol; step 5, sterilization, obtain salt-free soy sauce. The preparation method of salt-free soy sauce provided by the present invention adopts alcohol water to mix with koji material to form sauce mash, and alcohol water completely replaces traditional salt water, which can not only meet the standard of salt-free soy sauce, but also can play the role of sterilization and antiseptic. At the same time, in the process of preparation, combined with distillation, process sterilization and anaerobic and aerobic fermentation processes, not only can the alcohol taste in soy sauce be reduced, soy sauce is flavored and flavored, but also miscellaneous bacteria can be prevented from breeding, and fermentation operation is ensured to proceed normally.

Description

Technical Field

[0001] The invention relates to the technical field of condiment preparation, in particular to salt-free soy sauce and a preparation method thereof. Background Art

[0002] Soy sauce is a traditional Chinese specialty fermented condiment. It is used to season food with its unique color, aroma and taste to promote appetite. Traditional soy sauce has the characteristics of high salt content, and the salt content is mostly above 16% (m / v). The various reduced-salt soy sauces currently on the market still have a salt content of about 8% (m / v). At present, the schemes for preparing salt-free soy sauce mainly include the following three: one is to adopt a salt-free high-temperature short-time fermentation scheme, but the soy sauce obtained has a bitter and astringent flavor; the second is to use alcohol instead of salt to inhibit the reproduction of bacteria during the fermentation process, which can effectively complete the fermentation process, but the alcohol content in the resulting soy sauce is high, the alcohol taste is too strong, and there is a pungent alcohol taste, and the aroma and taste of the soy sauce are slightly poor; the third is to brew a salt-free soy sauce product through staged fermentation and accurate control of temperature and oxygen content. During the period, nutrient activation liquid, red yeast rice and Chinese medicinal materials are combined to comprehensively prevent the fermentation process from rotting and breeding bacteria. The antibacterial effect of the materials selected by this method is poor, and the fermentation process is prone to sourness, resulting in fermentation failure. Therefore, there is an urgent need for a method for preparing a salt-free soy sauce with rich sauce flavor and delicious taste. Summary of the invention

[0003] The object of the present invention is to provide a salt-free soy sauce and a preparation method thereof, so as to at least partially solve the technical problems mentioned in the above background technology that the soy sauce has a strong alcohol taste, a poor soy sauce flavor, and is easy to breed miscellaneous bacteria.

[0004] To achieve the above object, the present invention provides a method for preparing salt-free soy sauce, which comprises the following steps:

[0005] Step 1, raw material processing and koji making: steaming soybeans and / or defatted soybeans, mixing with crushed roasted wheat, and inoculating with seed koji to obtain koji material;

[0006] Step 2, salt-free fermentation: mixing the koji material with alcohol water to form a sauce mash, and fermenting the sauce mash for 1-6 months;

[0007] Step 3, squeezing and extracting juice: squeezing the fermented soy mash to extract juice to obtain high-alcohol soy sauce;

[0008] Step 4, distillation: distilling the high-alcohol soy sauce to reduce the alcohol content;

[0009] Step 5, sterilization: sterilizing the distilled soy sauce to obtain salt-free soy sauce;

[0010] Step 6, raw flavor and aroma fermentation: fermenting the sterilized salt-free soy sauce with raw flavor and aroma;

[0011] Step 7, aseptic filling: sterilize, filter and fill the salt-free soy sauce after raw flavor enhancement to obtain the finished salt-free soy sauce.

[0012] In a preferred embodiment, in step 2, the ethanol concentration in the alcohol water is 10%-25% (v / v). The appropriate alcohol concentration can also play a role in sterilization and preservation during the fermentation process of the sauce mash. If the ethanol concentration is too low, it will affect the antibacterial effect and the fermentation process will be prone to rancidity. If the ethanol concentration is too high, it will affect the enzymatic hydrolysis effect.

[0013] In a preferred embodiment, in step 4, the distillation temperature is set at 40-60°C. If the distillation temperature is set too low, the reduction in alcohol content will not reach the expected level. If the distillation temperature is set too high, the soy sauce will easily have a burnt smell, affecting the flavor of the soy sauce.

[0014] In a preferred embodiment, the raw flavoring and aromatizing fermentation step in step 6 comprises:

[0015] Anaerobic fermentation: the sterilized salt-free soy sauce is inoculated with lactic acid bacteria for anaerobic pure fermentation. Anaerobic fermentation by lactic acid bacteria is conducive to the production of sour taste, and the flavor and taste of soy sauce are effectively improved. After the anaerobic fermentation is completed, the pH is below 5.2, which can provide an environment for yeast to reproduce and is conducive to the production of sour taste.

[0016] In a preferred embodiment, the raw flavor and aroma fermentation step in step 6 further comprises:

[0017] Aerobic fermentation: The salt-free soy sauce obtained after anaerobic fermentation is inoculated with flavoring yeast for aerobic pure fermentation. Aerobic fermentation with flavoring yeast can enhance the flavor of soy sauce and make it more intense.

[0018] In a preferred embodiment, the anaerobic fermentation and the aerobic fermentation are both carried out in a sterile environment. Since the alcohol content has been reduced in the distillation process, in order to prevent the growth of bacteria, both fermentation processes need to be carried out in a sterile environment.

[0019] On the other hand, the present invention also provides a technical solution for salt-free soy sauce, which is prepared by the preparation method described in any of the above solutions.

[0020] Compared with the prior art, the invention has the beneficial effects that: the invention adopts the three-step fermentation method of alcohol fermentation, lactic acid fermentation and yeast fermentation to complete the preparation of salt-free soy sauce with rich sauce flavor and delicious taste. By adopting alcohol water and koji material to mix and prepare the sauce mash, alcohol water completely replaces the traditional salt water, which can not only meet the standard of salt-free soy sauce, but also alcohol water with suitable ethanol concentration can play a role of sterilization and preservation during the fermentation process of the sauce mash, and effectively inhibit the reproduction of miscellaneous bacteria. At the same time, in the process of preparation, the distillation process, the process sterilization process and the anaerobic and aerobic fermentation process are combined, which can not only effectively reduce the alcohol taste in the soy sauce, enhance the flavor of the soy sauce, but also prevent the growth of miscellaneous bacteria, and effectively ensure the normal fermentation operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a process flow chart for preparing salt-free soy sauce. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 The invention discloses a method for preparing salt-free soy sauce, comprising the following steps:

[0024] Step 1: Raw material processing and koji making

[0025] Soybeans and / or defatted soybeans are steamed under high pressure, mixed with crushed roasted wheat in a ratio of 1:0.3-1.2, seed koji is inoculated, and koji making is performed, which specifically includes the following steps:

[0026] 1.1 The soybeans and / or defatted soybeans are subjected to high pressure cooking with steam, the processing pressure is set to 0.1-0.25MPa, and the processing time is 3-8min, so as to achieve the effect of complete material protein denaturation without excessive denaturation.

[0027] 1.2 The wheat is baked with hot air, the hot air temperature is higher than 200℃, the material temperature is greater than 160℃, the processing time is 20 to 60 seconds, and the expansion rate reaches more than 1.5 after processing, and it is not burnt, and it is crushed with a pulverizer.

[0028] 1.3 Mix the steamed soybeans and / or defatted soybeans with crushed roasted wheat to form a mixed koji material.

[0029] 1.4 The mixed koji material is inoculated with Aspergillus oryzae, and the inoculation ratio of Aspergillus oryzae is 0.05%-0.5%.

[0030] 1.5 After inoculation, ventilation and koji making are carried out. The koji making temperature is 28-40℃, the time is 35-48h, and the ventilation humidity is above 90%RH. After completion, the koji material is obtained.

[0031] Step 2: Salt-free fermentation

[0032] The koji material obtained after koji making is mixed with alcohol water to form a sauce mash. The ethanol concentration in the alcohol water needs to be reasonably controlled. If the ethanol concentration is too low, the antibacterial effect will be affected, and sourness will easily occur during the fermentation process. If the ethanol concentration is too high, the enzymatic hydrolysis effect will be affected. In the present invention, the ethanol concentration in the alcohol water is set at 10%-25% (v / v), the weight of the alcohol water is 1.6-2.0 times the weight of the raw materials (soybeans and wheat), the sauce mash needs to be fermented for 1 to 6 months, and the fermentation temperature is set to 10 to 30°C.

[0033] Step 3: Squeeze the juice

[0034] The fermented mash is squeezed to extract the juice to form high-alcohol soy sauce A, the alcohol content of which is between 8% and 20%.

[0035] Step 4, distillation

[0036] The alcohol content in high-alcohol soy sauce A is reduced by vacuum distillation. The distillation temperature is set at 40-60°C and the duration is about 30 minutes. The specific duration is set according to the distillation temperature. The distillation temperature needs to be reasonably controlled. If the distillation temperature is set too low, the alcohol content reduction value will not meet expectations. If the distillation temperature is set too high, the soy sauce will easily produce a burnt smell, affecting the flavor of the soy sauce. After distillation, distilled soy sauce B is obtained, and the alcohol content at this time is reduced to 0-5%. The alcohol obtained by distillation can be used for cyclic fermentation.

[0037] Step 5, Sterilization

[0038] The distilled soy sauce B is subjected to ultra-high temperature sterilization (115-130°C), and salt-free soy sauce C is obtained after about 20-30 seconds. The aroma and taste of the salt-free soy sauce C are slightly worse, and the raw flavor is required to be enhanced.

[0039] Step 6: Raw flavor and aroma fermentation

[0040] 6.1 Anaerobic fermentation

[0041] In a completely closed sterile environment, the unsalted soy sauce C is inoculated with lactic acid bacteria for anaerobic pure fermentation, and the pH is reduced to below 5.2, providing an environment for yeast to reproduce and facilitating the production of sour taste. The fermentation temperature is set at 30-40°C and the fermentation time is 3-7 days to obtain the flavored soy sauce D.

[0042] 6.2 Aerobic fermentation

[0043] In a completely closed aseptic environment, sterile air is introduced, and the flavoring yeast is inoculated into the flavoring soy sauce D for aerobic pure fermentation. The fermentation temperature is set at 25-30°C and the fermentation time is 2-5 days. The flavoring is completed to obtain the salt-free soy sauce E.

[0044] Step 7, Aseptic Filling

[0045] The salt-free soy sauce E is blended, sterilized, filtered, and then packaged as a salt-free soy sauce finished product.

[0046] The salt-free soy sauce preparation method provided by the present invention only uses alcohol water and koji materials to prepare the sauce mash, and the alcohol water completely replaces the traditional salt water, which can not only meet the standard of salt-free soy sauce, but also the alcohol water with a suitable ethanol concentration can play a role of sterilization and preservation during the fermentation process of the sauce mash, and effectively inhibit the reproduction of miscellaneous bacteria. However, completely using alcohol fermentation will bring two problems: the alcohol taste is too strong, and the aroma and taste of the soy sauce are slightly poor.

[0047] In order to solve the problem of excessive alcohol taste, the present invention adopts a distillation process after fermentation, which can effectively reduce the alcohol content in the soy sauce. The sterilization process is immediately adopted after distillation, which can effectively compensate for the hidden danger of bacteria breeding caused by the reduction of alcohol content.

[0048] Aiming at the problem of poor aroma and taste of soy sauce, the anaerobic fermentation and aerobic fermentation performed after the sterilization process can enhance the flavor of the soy sauce. Meanwhile, both the anaerobic fermentation and aerobic fermentation processes adopt pure fermentation in a closed environment, which can effectively prevent the growth of miscellaneous bacteria.

[0049] The present invention is further described in detail below in conjunction with the embodiments. It should also be understood that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above content of the present invention all belong to the scope of protection of the present invention. Example 1

[0050] The method for preparing the salt-free soy sauce disclosed in this embodiment comprises the following steps:

[0051] Step 1: Raw material processing and koji making

[0052] Prepare 1 kg of defatted soybeans and 0.5 kg of wheat, steam the defatted soybeans at a pressure of 0.2 MPa for 5 minutes, bake and crush the wheat, mix the steamed defatted soybeans and the crushed baked wheat, inoculate Aspergillus oryzae at a ratio of 0.5%, make koji after mixing, and obtain koji material after koji making.

[0053] Step 2: Salt-free fermentation

[0054] The koji obtained after koji making is evenly mixed with alcohol water to form a sauce mash. The ethanol concentration in the alcohol water is 20% (v / v), the amount of alcohol water is 3L, the fermentation temperature of the sauce mash is set to 25°C, and the fermentation time is 6 months.

[0055] Step 3: Squeeze the juice

[0056] The fermented mash is squeezed to extract juice to form high-alcohol soy sauce A, at which the alcohol content is 16% (v / v).

[0057] Step 4, distillation

[0058] The alcohol content in high-alcohol soy sauce A was reduced by vacuum distillation. The distillation temperature was set at 50° C. After distillation, distilled soy sauce B was obtained, and the alcohol content at this time was 1%.

[0059] Step 5, Sterilization

[0060] The distilled soy sauce B is subjected to ultra-high temperature sterilization at a temperature of 121° C. for 20 seconds to form a salt-free soy sauce C, which is then cooled for the next step of processing.

[0061] Step 6, anaerobic fermentation

[0062] The salt-free soy sauce C was inoculated with lactic acid bacteria for anaerobic pure fermentation, the pH was lowered to 5.0, the fermentation temperature was 36°C, and the fermentation time was 5 days, thereby obtaining the flavored soy sauce D.

[0063] Step 7, aerobic fermentation

[0064] The flavoring soy sauce D to be flavored is inoculated with flavoring yeast for aerobic pure strain fermentation at a fermentation temperature of 28° C. for 3 days to complete the flavoring and obtain salt-free soy sauce E.

[0065] Step 8, Aseptic Filling

[0066] The salt-free soy sauce E is blended, sterilized, filtered, and then packaged into the salt-free soy sauce finished product F. Example 2

[0067] The method for preparing the salt-free soy sauce disclosed in this embodiment comprises the following steps:

[0068] Step 1: Raw material processing and koji making

[0069] Prepare 1 kg of defatted soybeans and 0.5 kg of wheat, steam the defatted soybeans at a pressure of 0.2 MPa for 5 minutes, bake and crush the wheat, mix the steamed defatted soybeans and the crushed baked wheat, inoculate Aspergillus oryzae at a ratio of 0.5%, mix and make koji, and obtain koji material after koji making.

[0070] Step 2: Salt-free fermentation

[0071] The koji obtained after koji making is evenly mixed with alcohol water to form a sauce mash. The ethanol concentration in the alcohol water is 10% (v / v), the amount of alcohol water is 3L, the fermentation temperature of the sauce mash is set to 25°C, and the fermentation time is 6 months.

[0072] Step 3: Squeeze the juice

[0073] The fermented mash is squeezed to extract juice to form high-alcohol soy sauce A, at which the alcohol content is 8% (v / v).

[0074] Step 4, distillation

[0075] The alcohol content in high-alcohol soy sauce A was reduced by vacuum distillation. The distillation temperature was set at 40°C. After distillation, distilled soy sauce B was obtained, and the alcohol content at this time was 0.7%.

[0076] Step 5, Sterilization

[0077] The distilled soy sauce B is subjected to ultra-high temperature sterilization at a temperature of 121° C. for 20 seconds to form a salt-free soy sauce C, which is then cooled for the next step of processing.

[0078] Step 6, anaerobic fermentation

[0079] The salt-free soy sauce C was inoculated with lactic acid bacteria for anaerobic pure fermentation, the pH was lowered to 5.0, the fermentation temperature was 30°C, and the fermentation time was 7 days, thereby obtaining the flavored soy sauce D.

[0080] Step 7, aerobic fermentation

[0081] The flavoring soy sauce D to be flavored is inoculated with flavoring yeast for aerobic pure strain fermentation at a fermentation temperature of 30° C. for 2 days to complete the flavoring and obtain salt-free soy sauce E.

[0082] Step 8, Aseptic Filling

[0083] The salt-free soy sauce E is blended, sterilized, filtered, and then packaged into the salt-free soy sauce finished product F. Example 3

[0084] The method for preparing the salt-free soy sauce disclosed in this embodiment comprises the following steps:

[0085] Step 1: Raw material processing and koji making

[0086] Prepare 1 kg of defatted soybeans and 0.5 kg of wheat, steam the defatted soybeans at a pressure of 0.2 MPa for 5 minutes, bake and crush the wheat, mix the steamed defatted soybeans and the crushed baked wheat, inoculate Aspergillus oryzae at a ratio of 0.5%, mix and make koji, and obtain koji material after koji making.

[0087] Step 2: Salt-free fermentation

[0088] The koji obtained after koji making is evenly mixed with alcohol water to form a sauce mash. The ethanol concentration in the alcohol water is 25% (v / v), the amount of alcohol water is 3L, the fermentation temperature of the sauce mash is set to 25°C, and the fermentation time is 6 months.

[0089] Step 3: Squeeze the juice

[0090] The fermented mash is squeezed to extract juice to form high-alcohol soy sauce A, at which the alcohol content is 20% (v / v).

[0091] Step 4, distillation

[0092] The alcohol content in high-alcohol soy sauce A was reduced by vacuum distillation. The distillation temperature was set at 60°C. After distillation, distilled soy sauce B was obtained, and the alcohol content at this time was 1.9%.

[0093] Step 5, Sterilization

[0094] The distilled soy sauce B is subjected to ultra-high temperature sterilization at a temperature of 121° C. for 20 seconds to form a salt-free soy sauce C, which is then cooled for further processing.

[0095] Step 6, anaerobic fermentation

[0096] The salt-free soy sauce C was inoculated with lactic acid bacteria for anaerobic pure fermentation, the pH was lowered to 5.0, the fermentation temperature was 40°C, and the fermentation time was 3 days, thereby obtaining the flavored soy sauce D.

[0097] Step 7, aerobic fermentation

[0098] The flavoring soy sauce D to be flavored is inoculated with flavoring yeast for aerobic pure strain fermentation at a fermentation temperature of 25° C. for 5 days to complete the flavoring and obtain salt-free soy sauce E.

[0099] Step 8, Aseptic Filling

[0100] The salt-free soy sauce E is blended, sterilized, filtered, and then packaged into the salt-free soy sauce finished product F.

[0101] The six groups of samples A, B, C, D, E, and F formed in the preparation process of the salt-free soy sauce preparation method provided in Example 1 were tested or evaluated for soy sauce index, bacterial colony, aroma, and taste to form an evaluation table, as shown in Table 1:

[0102] Table 1 Sample evaluation table for Example 1

[0103]

[0104] As shown in Table 1, there is no significant difference in the basic physical and chemical indicators of soy sauce such as amino acid nitrogen, total nitrogen and soluble salt-free solids among the six groups of samples; the total number of colonies in each link of the preparation process is within the standard through the combination of alcohol-water fermentation and sterilization process, and the anaerobic and aerobic fermentation process in a closed environment; the ethanol concentration of sample A before the distillation process is significantly higher than that of other samples, with a strong alcohol taste and a significant alcohol-killing taste. Sample D after anaerobic pure fermentation tastes more delicious and mellow than sample C, and has no significant bitterness. Sample E after aerobic pure fermentation has a stronger sauce flavor than sample D.

[0105] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing salt-free soy sauce, characterized in that: The following steps are involved: Step 1, raw material processing and koji making: steaming soybeans and / or defatted soybeans, mixing with crushed roasted wheat, and inoculating with seed koji to obtain koji material; Step 2, salt-free fermentation: mixing the koji material with alcohol water to form a sauce mash, and fermenting the sauce mash for 1-6 months; Step 3, squeezing and extracting juice: squeezing the fermented soy mash to extract juice to obtain high-alcohol soy sauce; Step 4, distillation: distilling the high alcohol soy sauce to reduce the alcohol content, and the distillation temperature is set at 40-60° C.; Step 5, sterilization: sterilizing the distilled soy sauce to obtain salt-free soy sauce; Step 6, raw flavor and aroma fermentation: fermenting the sterilized salt-free soy sauce with raw flavor and aroma; Step 7, aseptic filling: sterilizing, filtering and filling the salt-free soy sauce after the raw flavor is enhanced to obtain the finished salt-free soy sauce; The raw flavoring and aroma-enhancing fermentation step of step 6 comprises: Anaerobic fermentation: sterilized salt-free soy sauce is inoculated with lactic acid bacteria for anaerobic pure fermentation; Aerobic fermentation: the salt-free soy sauce obtained after anaerobic fermentation is inoculated with flavoring yeast for aerobic pure fermentation; In step 2, the ethanol concentration in the alcohol water is 10%-25% v / v.

2. The method for preparing salt-free soy sauce according to claim 1, characterized in that The anaerobic fermentation and aerobic fermentation are both carried out in a sterile environment.

3. The salt-free soy sauce prepared by the preparation method according to any one of claims 1 to 2.

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