Preservative-free in-bag fermented pickled vegetables and preparation method thereof

Abstract

The invention discloses a preservative-free in-bag fermented pickled green vegetable and a preparation method thereof, and the preservative-free in-bag fermented pickled green vegetable mainly comprises the following raw materials: leaf mustard, purified water, iodine-free salt, glucose, a composite zymophyte agent and a composite spice having a synergistic effect on zymophyte, according to the fermented pickled green vegetables, through the pretreatment of the leaf mustard and the synergistic effect of the compound spices, the compound fermentation inoculant and the fermentation bag, and particularly through the synergistic effect of the special compound spices and the compound fermentation strain, the dosage of the fermentation inoculant is greatly reduced, no preservative is added, and the raw materials are subjected to closed non-aerogenesis fermentation in the bag; according to the method, the quality and the taste of the pickled green vegetables are guaranteed, the fermentation bags are not expanded during fermentation and preservation, microbial pollution is avoided, high-salt wastewater is not discharged, the taste and the quality of the product are guaranteed, meanwhile, the formula is clean, and the method has extremely high practical guiding significance.

Description

Technical Field

[0001] The present invention relates to the field of preparation of fermented foods, and particularly relates to a bag-internal fermentation pickled Chinese cabbage without preservatives and a preparation method thereof. Background Art

[0002] As a traditional fermented food, pickled Chinese cabbage is widely loved by consumers for its unique flavor and taste. The production methods of traditional pickled Chinese cabbage include large-pool fermentation and old-vat fermentation. The fermentation process relies on the natural fermentation of environmental microbial populations or is regulated by selecting specific direct-inoculation microbial agents. Large-pool fermentation usually uses large-scale cement pools or earth pits for large-scale production. Although the cost is low and the output is high, due to the open or semi-open fermentation environment, it is easily contaminated by miscellaneous bacteria, resulting in unstable quality, and it is difficult to uniformly control the temperature and salinity. Old-vat fermentation uses ceramic vats or jars, and forms an anaerobic environment through sealing to promote the fermentation of lactic acid bacteria. However, ceramic vats occupy a large area and are easily damaged, have high requirements for manual operation, and it is difficult to achieve large-scale and high-efficiency production. Both methods are highly dependent on the environment and experience, have poor quality stability, lack standardized management for industrial production, and it is difficult to avoid the uncertainties brought by manual operation.

[0003] The bag-internal fermentation technology is a method for fermenting foods using a sealed bag, which has received extensive attention in the field of food processing in recent years. By sealing food raw materials and a fermenting agent in a specific fermenting bag to create a suitable fermentation environment, it can effectively improve food quality and extend the shelf life. At present, there have been many research results in aspects such as fermentation process control, microbial community analysis, and product quality evaluation of this technology.

[0004] In terms of formula design, currently almost all bag-internal pickled vegetable products add preservatives during the preparation of the fermentation broth. Since the fermentation process of this product is carried out after being vacuum-sealed and bagged, the entire fermentation stage is in a closed environment. Therefore, the preservatives can only be added before bagging and cannot be supplemented in the middle and late stages of fermentation. Based on this technological feature, the method of adding preservatives is not applicable to the production of bag-internal fermentation products. In addition, adding preservatives has two disadvantages: on the one hand, the use of food additives may cause disgust among consumers; on the other hand, some preservatives have an inhibitory effect on the core lactic acid bacteria in pickled vegetables, which may affect the fermentation effect and ultimately lead to a decline in the quality of pickled vegetables or an extension of the fermentation time.

[0005] Therefore, it is urgent for scientific research personnel to further optimize and innovate in this field to promote the application and development of the bag-internal fermentation technology for pickled vegetables.

[0006] The present invention aims to develop a preservative-free fermented pickled greens product in a bag, which is mainly composed of the following raw materials: mustard, purified water (process water that has undergone reverse osmosis and ozone ultraviolet sterilization), iodine-free salt, glucose, composite spices and composite fermentation bacteria. The product is prepared only once through a specific pretreatment method, the screening of composite spices, the synergistic enhancement of composite fermentation strains, and the reasonable screening of fermentation packaging bags, so that the raw materials can be fermented in a closed and non-gas-producing manner in the bag, which not only ensures the excellent quality and taste of the pickled greens, but also can achieve the fermentation bag during fermentation and storage without bulging, no microbial contamination, and no discharge of high-salt wastewater. The appropriate pretreatment method, specific composite fermentation bacteria and composite spices synergize fermentation and antagonize the growth of miscellaneous bacteria, guide the smooth progress of lactic acid fermentation, and avoid the phenomenon of gas production and bag bulging during the fermentation process in the bag. The structure of natural fermentation flora is complex. Some aromatic fungi can make kimchi have a mellow flavor. The flavor of inoculated fermentation is weaker than that of natural fermentation. Screening suitable compound spices can enhance the flavor of kimchi and make up for the above disadvantages. On the other hand, it can also promote the growth of compound fermentation bacteria and significantly reduce the amount of bacterial agents. The use of compound spices and compound fermentation agents can synergistically improve the fermentation quality of kimchi and completely eliminate the addition of food preservatives. Reasonable packaging blocks the water and gas exchange between the fermentation system and the outside world, avoiding the growth of residual aerobic bacteria (especially yeast) in the fermentation system, which leads to flower and film production. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art, and to provide a preservative-free fermented pickled greens in a bag and a preparation method thereof, which are mainly composed of the following raw materials: mustard, pure water, iodine-free salt, glucose, composite fermentation bacteria and composite spices that have a synergistic effect on fermentation bacteria. The fermented pickled greens are prepared by the synergistic effect of mustard pretreatment, composite spices, composite fermentation bacteria and fermentation bags, especially by utilizing the synergistic effect of special composite spices and composite fermentation bacteria, which greatly reduces the amount of fermentation bacteria, does not require the addition of preservatives, and does not require subsequent sterilization processes. Reasonable packaging blocks the water and gas exchange between the fermentation system and the outside world, so that the raw materials are fermented in a closed and non-gas-producing manner in the bag, which not only ensures that the pickled greens have excellent quality and taste, but also can achieve that the fermentation bag does not swell during fermentation and storage, does not have microbial contamination, and does not discharge high-salt wastewater. The product achieves a clean formula while ensuring taste and quality, and has extremely strong practical guiding significance.

[0008] In order to achieve the above technical effects, the following technical solutions are adopted: A method for preparing preservative-free fermented pickled green vegetables in a bag comprises the following steps: Step S1: Pickled vegetable raw materials selection Remove impurities and inedible parts from fresh mustard greens, process them into the required shape and size, wash them and set them aside; Step S2: Pre-treatment of raw materials by blanching for bacteria control Soak the mustard greens obtained in step S1 in a blanching solution containing calcium chloride for blanching to remove miscellaneous bacteria. After fishing them out, cool them with strong cold air, and then pack them into fermentation bags for standby after cooling; Step S3: Preparation of fermentation broth Weigh purified water according to the mass of the mustard greens, add appropriate amount of iodine-free salt and glucose, stir and boil until completely dissolved; add the water extract of compound spices to the boiling mixture, stir evenly, and add the compound fermentation starter after the liquid cools down, and mix well for standby; Step S4: Packaging Quantitatively fill the cooled fermentation broth in step S3 into the fermentation bags and mix with the mustard greens in S2, seal them under vacuum, and place them in a cool place for drying; Step S5: Fermentation Place the vacuum-sealed fermentation bags obtained in step S4 in the fermentation workshop and start fermentation until the pickled vegetables are fully mature.

[0009] Furthermore, in step S2, the mass ratio of calcium chloride in the blanching solution is 0.1% - 0.3%; the temperature of the blanching solution is boiling water at 100°C, and the blanching time of the mustard greens is 1 min; the amount of the blanching solution used is 8 - 10 times the mass of the mustard greens; the water for the blanching solution is reverse osmosis-treated tap water or groundwater.

[0010] Furthermore, the specific parameters of the strong cold air cooling in step S2 are as follows: Wind speed is 5 - 10 m / s, cooling time is 10 - 15 min, cooling temperature is 4 - 10°C, air filtration standard: According to "GB / T 14295 Air Filters", adopt a sub-high efficiency air filter, the efficiency level is YG grade, and the rated air passing efficiency ≥ 95%.

[0011] Furthermore, in step S3, the mass fraction ratio of the mustard greens, purified water, iodine-free salt, glucose, compound spices, and compound fermentation starter is: 30 - 60:50 - 60:4 - 4.5:0.5 - 2:0.6 - 1.4:0.2 - 0.5; the purified water is reverse osmosis-treated and ozone-ultraviolet sterilized tap water or groundwater.

[0012] Furthermore, in step S3, the compound fermentation starter is a combination of a direct-fed starter of Lactiplantibacillus plantarum and a direct-fed starter of Pediococcus acidilactici. The viable count of the direct-fed starter of Lactiplantibacillus plantarum ≥ 10 10 CFU / g; the viable count of the direct-fed starter of Pediococcus acidilactici ≥ 10 10 CFU / g; the configuration ratio of the direct-fed starter of Lactiplantibacillus plantarum and the direct-fed starter of Pediococcus acidilactici in terms of viable count is: 2 - 2.5:0.5 - 1.

[0013] Further, in step S3, the compound spice is a combination of nutmeg, fennel, dill, and caraway. Among them, in the compound spice, the mass fraction ratio of nutmeg, fennel, dill, and caraway is: 1.5 - 2: 1.5 - 2: 2.5 - 3: 1 - 1.5.

[0014] Further, in step S3, when the liquid is cooled to 40 - 45 °C, a compound fermentation agent is added.

[0015] Further, in step S4, the fermentation bag has an oxygen transmission rate (OTR) < 1 cm 3 / m 2 ·24 h·atm, and a water vapor transmission rate (WVTR) < 1 g / m 2 ·24 h food packaging bag. In the present invention, a PET / EVOH / PE composite film packaging bag (OTR ≈ 0.1 - 0.5, WVTR ≈ 0.8) is used, which has good acid resistance (the packaging material is immersed in an acetic acid solution with a pH ≈ 3 for 30 days without delamination or corrosion); the mass ratio of the fermentation broth to mustard is 1: 0.6 - 1.

[0016] Further, the fermentation time in step S5 is 15 - 20 d.

[0017] A bagged fermented pickled Chinese cabbage without preservatives is prepared by using any one of the above preparation methods.

[0018] The beneficial effects of the present invention are: The present invention discloses a bag-internal fermented pickled mustard without preservatives and its preparation method; it mainly consists of the following raw materials: mustard, purified water, iodine-free table salt, glucose, a compound fermentation bacterium agent, and a compound spice that has a synergistic effect on the fermentation bacteria. Through the synergistic effect of the pretreatment of mustard, the compound spice, the compound fermentation bacterium agent, and the fermentation bag, especially the synergistic effect of the special compound spice and the compound fermentation bacterial strain, the dosage of the fermentation bacterium agent is greatly reduced, the addition of food preservatives is completely cancelled, the growth of miscellaneous bacteria is inhibited by relying on the acid production of lactic acid bacteria and the control of the fermentation environment, avoiding the potential health risks of synthetic preservatives and being more suitable for the preparation process of bag-internal fermented pickled mustard. While simplifying the production process flow and shortening the fermentation time, it endows the product with the same or even better sensory characteristics; through the screening and optimization of the pretreatment process, the total amount of microorganisms is controlled from the source end and the taste of the product is ensured; lactic acid bacteria agents that do not produce gas are compounded in an appropriate proportion, which improves the taste of the product and accelerates the acidification process on the premise of ensuring that the product does not produce gas during bag-internal fermentation; a compound spice that has a synergistic effect on the fermentation bacterial strain during the fermentation process is screened and reasonably compounded, increasing the flavor of the finished product, making up for the deficiency of insufficient flavor in inoculation fermentation, and at the same time inhibiting the growth of miscellaneous bacteria (especially the gas-producing miscellaneous bacteria), ensuring the quality stability of the product; a packaging bag made of a suitable material is selected to ensure its gas barrier property and water barrier property, avoiding the exchange of water and gas inside and outside the bag, especially avoiding the entry of external oxygen and activating the fermentation of aerobic microorganisms (especially yeasts), maximizing the possibility of avoiding contamination by miscellaneous bacteria, and can further reduce the inoculation amount of the fermentation bacterial strain in cooperation under the condition of ensuring no contamination by miscellaneous bacteria, and no subsequent sterilization process is required.

[0019] By using bacteria to inhibit bacteria and using bags instead of jars, the bag-internal fermentation process of pickled mustard in the present invention optimizes and upgrades pickled mustard from the traditional ancient brewing method to a precise fermentation mode. The production process is simple, the process is convenient, the cost is low, the requirement for the site area is low, greatly improving the feasibility of industrial production of the product, and being more conducive to the industrialization, scale, and standardization development of the pickled vegetable industry; while ensuring the taste and quality of the product, the formula is clean (avoiding the addition of preservatives), enabling a wider market acceptance and providing significant health benefits, and having extremely strong practical guiding significance. Description of the Drawings

[0020] Figure 1 It is a bar chart of the sensory evaluation scores of the bag-internal fermented pickled mustard in the examples and comparative examples of the present invention; Figure 2 It is a bar chart of the pH value results of the bag-internal fermented pickled mustard in the examples and comparative examples of the present invention; Figure 3 It is a bar chart of the total acid results of the bag-internal fermented pickled mustard in the examples and comparative examples of the present invention; Figure 4 It is a bar chart of the soup turbidity results of the bag-internal fermented pickled mustard in the examples and comparative examples of the present invention. Detailed implementation manners

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0023] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0024] The bacterial agents, their manufacturers and parameters in the following examples and comparative examples are listed in Table 1: Table 1 Information such as the sources and manufacturers of the bacterial agents used in this example and the comparative example

[0025] Note: The bacterial strains used do not need to be activated. They are directly weighed and added in powder form.

[0026] In the present invention, PET / EVOH / PE composite film packaging bags (OTR≈0.1~0.5, WVTR≈0.8) are used, which have good acid resistance (the packaging material is immersed in an acetic acid solution with pH≈3 for 30 days, without delamination or corrosion).

[0027] Example 1: This example relates to a bagged fermented pickled mustard greens without the addition of preservatives and a preparation method thereof: The raw material formula of the product and the mass of each component are as follows: 60 kg of mustard greens, 600 kg of blanching water (containing 0.3% calcium chloride), 60 kg of purified water, 4.5 kg of iodine-free salt, 2 kg of glucose, 0.18 kg of nutmeg, 0.18 kg of fennel, 0.25 kg of dill, 0.12 kg of caraway, 0.34 kg of a direct-fed bacterial agent of Lactiplantibacillus plantarum, and 0.16 kg of a direct-fed bacterial agent of Pediococcus acidilactici.

[0028] The preparation process of the product is as follows: (1) Screening of raw materials for pickled mustard greens Remove impurities and inedible parts from fresh mustard greens, weigh 60 kg, wash and set aside; (2)Pretreatment (blanching for bacteria control) Blanch the mustard greens processed in step (1) in 600 kg of blanching water containing 0.3% calcium chloride for 1 min at a blanching temperature of 100 °C to remove miscellaneous bacteria. After fishing out, cool with strong cold air, with a wind speed of 5 - 10 m / s, a cooling time of 10 - 15 min, and a cooling temperature of 10 °C. Air filtration standard: According to "GB / T 14295 Air Filters", use a sub-high-efficiency air filter with an efficiency level of YG grade and a rated air passing efficiency ≥ 95%. After cooling, bag and set aside; (3)Boiling Weigh 60 kg of purified water, weigh 0.18 kg of nutmeg, 0.18 kg of fennel, 0.25 kg of dill, and 0.12 kg of caraway. After fully pulverizing to 200 mesh, pour into a filter bag and add to the purified water and boil for 30 min; (4)Fermentation broth preparation Add 4.5 kg of iodine-free salt and 2 kg of glucose to the spice extract obtained in step (3), stir and boil until completely dissolved; when the liquid cools to 45 °C, add 0.34 kg of direct-fed lactic acid bacteria of Lactobacillus plantarum and 0.16 kg of direct-fed lactic acid bacteria of Pediococcus acidilactici, mix well and set aside; (5)Packaging Quantitatively fill the cooled and inoculated fermentation broth in step (4) into packaging bags and mix with the mustard greens in step (2) in equal mass, vacuum seal, and place in a cool place to dry; The packaging bag material is a food-grade PET / EVOH / PE composite film packaging bag (OTR ≈ 0.1 - 0.5, WVTR ≈ 0.8), with good acid resistance (the packaging material is immersed in an acetic acid solution with pH ≈ 3 for 30 days without delamination or corrosion).

[0029] (6)Fermentation inside the bag Place the vacuum-sealed packaging bag obtained in step (5) in the fermentation workshop and ferment for 20 d until the pickled mustard greens are fully mature.

[0030] Example 2: This example relates to a pickled mustard greens with no preservative added and its preparation method: The raw material formula of this product and the mass of each component are as follows: 50 kg of mustard greens, 400 kg of blanching water (containing 0.2% calcium chloride), 60 kg of purified water, 4.3 kg of iodine-free salt, 0.5 kg of glucose, 0.14 kg of nutmeg, 0.14 kg of fennel, 0.20 kg of dill, 0.08 kg of caraway, 0.14 kg of direct vat inoculum of Lactobacillus plantarum, 0.06 kg of direct vat inoculum of Pediococcus acidilactici.

[0031] The preparation process of this product is as follows: (1)Screening of raw materials for pickled vegetables Remove impurities and inedible parts from fresh mustard greens, weigh 50 kg, wash and set aside; (2)Pretreatment (blanching and bacteria control) Blanch the mustard greens processed in step (1) in 400 kg of blanching water containing 0.2% calcium chloride for 1 min at a blanching temperature of 100°C to remove miscellaneous bacteria. After fishing out, cool it with strong cold air, with a wind speed of 5 - 10 m / s, a cooling time of 10 - 15 min, and a cooling temperature of 6°C. Air filtration standard: According to "GB / T 14295 Air Filters", use a sub-high efficiency air filter, with an efficiency level of YG grade, and the rated air passing efficiency ≥ 95%. After cooling, pack and set aside; (3)Boiling Weigh 55 kg of purified water, weigh 0.14 kg of nutmeg, 0.14 kg of fennel, 0.20 kg of dill, 0.08 kg of caraway, fully crush them to 200 mesh, put them into a filter bag, and add them to the purified water to boil for 60 min; (4)Fermentation broth preparation Add 4.3 kg of iodine-free salt and 0.5 kg of glucose to the spice extract obtained in step (3), stir and boil until completely dissolved; when the liquid cools to 40°C, add 0.14 kg of direct vat inoculum of Lactobacillus plantarum and 0.06 kg of direct vat inoculum of Pediococcus acidilactici, mix well and set aside; (5)Packaging Quantitatively fill the cooled and inoculated fermentation broth in step (4) into packaging bags, mix it with the mustard greens in step (2) in equal mass, seal it in a vacuum, and place it in a cool place to dry; The packaging bag material is a food-grade PET / EVOH / PE composite film packaging bag (OTR ≈ 0.1 - 0.5, WVTR ≈ 0.8), with good acid resistance (the packaging material is immersed in an acetic acid solution with pH ≈ 3 for 30 days, without delamination or corrosion).

[0032] (6)Fermentation inside the bag Place the vacuum-sealed packaging bag obtained in step (5) in the fermentation workshop and ferment for 18 d until the pickled vegetables are fully mature.

[0033] Example 3: This embodiment relates to a bag-in fermentation pickled Chinese cabbage without preservatives and its preparation method: The raw material formula of the product and the mass of each component are as follows: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, 0.20 kg of direct-fed starter of Lactiplantibacillus plantarum, 0.10 kg of direct-fed starter of Pediococcus acidilactici.

[0034] The preparation process of the product is as follows: (1)Screening of pickled Chinese cabbage raw materials Remove impurities and inedible parts from fresh mustard, weigh 50 kg, wash and set aside; (2)Pretreatment (blanching for bacteria control) Blanch the mustard processed in step (1) in 500 kg of blanching water containing 0.1% calcium chloride for 1 min at a blanching temperature of 100 °C to remove miscellaneous bacteria. After fishing out, cool it with strong cold air, with a wind speed of 5 - 10 m / s, a cooling time of 10 - 15 min, and a cooling temperature of 4 °C. The air filtration standard: According to "GB / T 14295 Air Filters", use a sub-high-efficiency air filter with an efficiency level of YG grade and a rated air passing efficiency ≥ 95%. After cooling, pack it in bags and set aside; (3)Boiling Weigh 50 kg of purified water, weigh 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, fully crush them to 200 meshes, put them into a filter bag, and add them to the purified water and boil for 35 min; (4)Fermentation broth preparation Add 4 kg of iodine-free salt and 1 kg of glucose to the spice extract obtained in step (3), stir and boil until completely dissolved; when the liquid cools to 42 °C, add 0.20 kg of direct-fed starter of Lactiplantibacillus plantarum and 0.10 kg of direct-fed starter of Pediococcus acidilactici, mix well and set aside; (5)Packaging Quantitatively fill the cooled and inoculated fermentation broth in step (4) into a packaging bag and mix it with the same mass of mustard in step (2), seal it under vacuum, and place it in a cool place to dry; The packaging bag material is a food-grade PET / EVOH / PE composite film packaging bag (OTR ≈ 0.1 - 0.5, WVTR ≈ 0.8), with good acid resistance (the packaging material is immersed in an acetic acid solution with pH ≈ 3 for 30 days without delamination or corrosion).

[0035] (6)In-bag fermentation Place the vacuum-sealed packaging bag obtained in step (5) in the fermentation workshop and ferment for 15 d until the pickled green vegetables are fully mature.

[0036] The design ideas of the following comparative examples are summarized in Table 1: The direct-fed starter of Lactiplantibacillus plantarum is set as A, the direct-fed starter of Pediococcus acidilactici is set as B, and the 4 kinds of spices nutmeg, fennel, dill, and caraway are set as C, D, E, and F respectively. In the comparative examples, codes will be used to explain the ideas.

[0037] Table 2 Design ideas of comparative examples

[0038] Comparative Example 1: This comparative example is based on Example 3, and its preparation method is basically the same as that of Example 3. The only difference is that: the blanching and bacteria control method for the mustard raw materials in the preparation process step (2) is replaced by microwave treatment, with parameters of 500 W, 100 °C, and the microwave treatment time is 2 min. Other preparation methods and formulas are the same as those in Example 3, and the pickled green vegetable products fermented in the bag are obtained.

[0039] Comparative Example 2: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that: the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, and 0.30 kg of the direct-fed starter of Pediococcus acidilactici.

[0040] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in the bag are obtained.

[0041] Comparative Example 3: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that: the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, and 0.30 kg of the direct-fed starter of Lactiplantibacillus plantarum.

[0042] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in the bag are obtained.

[0043] Comparative Example 4: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard greens, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of fennel, 0.32 kg of dill, 0.11 kg of caraway, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0044] The preparation method and formula are the same as those of Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0045] Comparative Example 5: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard greens, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of nutmeg, 0.32 kg of dill, 0.11 kg of caraway, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0046] The preparation method and formula are the same as those of Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0047] Comparative Example 6: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard greens, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.25 kg of nutmeg, 0.25 kg of fennel, 0.14 kg of caraway, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0048] The preparation method and formula are the same as those of Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0049] Comparative Example 7: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard greens, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.18 kg of nutmeg, 0.18 kg of fennel, 0.28 kg of dill, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0050] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0051] Comparative Example 8: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, 0.20 kg of direct vat inoculum of Leuconostoc mesenteroides, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0052] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0053] Comparative Example 9: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Lactococcus lactis.

[0054] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0055] Comparative Example 10: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of white pepper, 0.16 kg of fennel, 0.24 kg of dill, 0.08 kg of caraway, 0.20 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.10 kg of direct vat inoculum of Pediococcus acidilactici.

[0056] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0057] Comparative Example 11: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of mustard seeds, 0.24 kg of dill, 0.08 kg of caraway, 0.20 kg of direct-fed starter culture of Lactiplantibacillus plantarum, and 0.10 kg of direct-fed starter culture of Pediococcus acidilactici.

[0058] The preparation method and formula are the same as those in Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0059] Comparative Example 12: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.16 kg of white pepper, 0.08 kg of caraway, 0.20 kg of direct-fed starter culture of Lactiplantibacillus plantarum, and 0.10 kg of direct-fed starter culture of Pediococcus acidilactici.

[0060] The preparation method and formula are the same as those in Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0061] Comparative Example 13: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.16 kg of nutmeg, 0.16 kg of fennel, 0.24 kg of dill, 0.16 kg of coriander seeds, 0.20 kg of direct-fed starter culture of Lactiplantibacillus plantarum, and 0.10 kg of direct-fed starter culture of Pediococcus acidilactici.

[0062] The preparation method and formula are the same as those in Example 3, and a pickled green vegetable product with in-bag fermentation is obtained.

[0063] Comparative Example 14: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of fennel, 0.32 kg of dill, 0.11 kg of caraway, and 0.30 kg of direct-fed starter culture of Pediococcus acidilactici.

[0064] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0065] Comparative Example 15: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of nutmeg, 0.32 kg of dill, 0.11 kg of caraway, and 0.30 kg of direct-fed Pediococcus acidilactici.

[0066] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0067] Comparative Example 16: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.25 kg of nutmeg, 0.25 kg of fennel, 0.14 kg of caraway, and 0.30 kg of direct-fed Pediococcus acidilactici.

[0068] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0069] Comparative Example 17: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.18 kg of nutmeg, 0.18 kg of fennel, 0.28 kg of dill, and 0.30 kg of direct-fed Pediococcus acidilactici.

[0070] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage product is obtained.

[0071] Comparative Example 18: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of fennel, 0.32 kg of dill, 0.11 kg of caraway, and 0.30 kg of direct-fed Lactiplantibacillus plantarum.

[0072] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage products are obtained.

[0073] Comparative Example 19: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of nutmeg, 0.32 kg of dill, 0.11 kg of caraway, and 0.30 kg of direct vat inoculum of Lactiplantibacillus plantarum.

[0074] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage products are obtained.

[0075] Comparative Example 20: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.25 kg of nutmeg, 0.25 kg of fennel, 0.14 kg of caraway, and 0.30 kg of direct vat inoculum of Lactiplantibacillus plantarum.

[0076] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage products are obtained.

[0077] Comparative Example 21: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.18 kg of nutmeg, 0.18 kg of fennel, 0.28 kg of dill, and 0.30 kg of direct vat inoculum of Lactiplantibacillus plantarum.

[0078] The preparation method and formula are the same as those in Example 3, and the in-bag fermented pickled Chinese cabbage products are obtained.

[0079] Comparative Example 22: This comparative example is based on Example 3, and its preparation method is exactly the same as that in Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of fennel, 0.32 kg of dill, 0.11 kg of caraway, 0.67 kg of direct vat inoculum of Lactiplantibacillus plantarum, and 0.33 kg of direct vat inoculum of Pediococcus acidilactici.

[0080] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in bags are obtained.

[0081] Comparative Example 23: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.21 kg of nutmeg, 0.32 kg of dill, 0.11 kg of caraway, 0.67 kg of direct-fed probiotic Lactiplantibacillus plantarum, and 0.33 kg of direct-fed probiotic Pediococcus acidilactici.

[0082] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in bags are obtained.

[0083] Comparative Example 24: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.25 kg of nutmeg, 0.25 kg of fennel, 0.14 kg of caraway, 0.67 kg of direct-fed probiotic Lactiplantibacillus plantarum, and 0.33 kg of direct-fed probiotic Pediococcus acidilactici.

[0084] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in bags are obtained.

[0085] Comparative Example 25: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the raw material composition is: 50 kg of mustard, 500 kg of blanching water (containing 0.2% calcium chloride), 50 kg of purified water, 4 kg of iodine-free salt, 1 kg of glucose, 0.18 kg of nutmeg, 0.18 kg of fennel, 0.28 kg of dill, 0.67 kg of direct-fed probiotic Lactiplantibacillus plantarum, and 0.33 kg of direct-fed probiotic Pediococcus acidilactici.

[0086] The preparation method and formula are the same as those in Example 3, and the pickled green vegetable products fermented in bags are obtained.

[0087] Comparative Example 26: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the packaging bag material used in step (5) of the preparation is an EVOH food packaging bag with an oxygen transmission rate < 1 and a water vapor transmission rate > 1 (OTR < 1, high WVTR value).

[0088] The preparation method and formula are the same as those in Example 3, and the pickled green vegetables fermented in the bag are obtained.

[0089] Comparative Example 27: This comparative example is based on Example 3, and its preparation method is exactly the same as that of Example 3. The only difference is that the packaging bag material used in preparation step (5) is a BOPP / PVDC composite food packaging bag with an oxygen transmission rate > 1 and a water vapor transmission rate < 11 (high OTR value, WVTR < 1).

[0090] The preparation method and formula are the same as those in Example 3, and the pickled green vegetables fermented in the bag are obtained.

[0091] The pickled green vegetables fermented in the bag obtained in the above Examples 1 - 3 and Comparative Examples 1 - 27 were evaluated.

[0092] I. Bag swelling situation The bag swelling situations after fermentation in the above Examples 1 - 3 and Comparative Examples 1 - 27 were counted in Table 3: Table 3 Bag swelling situations after fermentation in Examples 1 - 3 and Comparative Examples 1 - 27

[0093] II. Sensory evaluation Product sensory evaluation method: Five industry experts were invited to formulate sensory evaluation criteria, as shown in Table 4. The weights of each index are as follows: taste 30%; flavor 20%; tissue state 30%; color and luster 20%. An appropriate amount of pickled green vegetables fermented in the bag was placed in a clean plate, randomly numbered and the placement positions were disrupted. A panel of 10 professionally trained sensory personnel was selected to score the pickled green vegetables with reference to Table 4. After each group was evaluated, they rinsed their mouths with clean water, and the results were averaged. The data results Figure 1 are shown as follows.

[0094] Table 4 Sensory evaluation criteria for pickled green vegetables fermented in the bag without preservative addition

[0095] III. pH value According to "GB5009.237 - 2016 Determination of pH value of foods", the pickled green vegetable liquid was stirred evenly with a glass rod, and the pH value was measured using a pH meter. Each sample was measured in parallel three times, and the average value was taken.

[0096] For the pickled green vegetables fermented in the bag obtained in Examples 1 - 3 and Comparative Examples 1 - 27, the pH value data results Figure 2 are shown as follows.

[0097] IV. Total acid The total acid was determined by the acid-base titration method in the GB 12456-2021 standard.

[0098] The total acid data results of the pickled green vegetables fermented in bags obtained in Examples 1 to 3 and Comparative Examples 1 to 27 Figure 3 are shown as follows.

[0099] V. Turbidity of the soup Referring to the spectrophotometry method in GB 13200-91 "Water Quality - Determination of Turbidity", it is expressed by the absorbance value of the sample at a wavelength of 680 nm.

[0100] The turbidity data results of the soup of the pickled green vegetables fermented in bags obtained in Examples 1 to 3 and Comparative Examples 1 to 27 Figure 4 are shown as follows.

[0101] Based on the comprehensive evaluation results, the three examples of this product are superior to Comparative Examples 1 to 27 in all evaluation parameters, and there are significant differences. Through the synergistic effects of the pretreatment of mustard, compound spices, compound fermentation agents, and fermentation bags, especially the synergistic effects of special compound spices and compound fermentation strains, the dosage of fermentation agents is greatly reduced, no preservatives need to be added, and no subsequent sterilization process is required. The raw materials are fermented in a sealed and non-gas-producing manner in the bag, which not only ensures excellent quality and taste of the pickled green vegetables, but also enables no bag swelling, no microbial contamination during the fermentation bag fermentation and storage, and no high-salt wastewater discharge. While ensuring the taste and quality, the product realizes formula cleaning.

[0102] In summary, the present invention discloses a bag-in fermentation pickled mustard greens without preservatives and its preparation method; it mainly consists of the following raw materials: mustard greens, purified water, iodine-free table salt, glucose, a compound fermentation bacterium agent, and a compound spice that has a synergistic effect on the fermentation bacteria. Through the pretreatment of mustard greens, the compound spice (nutmeg, fennel, dill, caraway), the compound fermentation bacterium agent, and the synergistic effect of the fermentation bag, especially the synergistic effect of the special compound spice and the compound fermentation bacteria species, the dosage of the fermentation bacterium agent is greatly reduced, the addition of food preservatives is completely cancelled, the natural acid production of lactic acid bacteria and the control of the fermentation environment are relied on to inhibit miscellaneous bacteria, avoiding the potential health risks of synthetic preservatives and being more suitable for the preparation process of bag-in fermentation pickled mustard greens. While simplifying the production process flow and shortening the fermentation time, it endows the product with the same or even better sensory characteristics; the product formula is optimized through the concept of clean label; through the screening and optimization of the pretreatment process, the total amount of microorganisms is controlled from the source end and the taste of the product is ensured; only through one preparation, lactic acid bacteria agents that do not produce gas are compounded in an appropriate proportion. On the premise of ensuring that the product does not produce gas during bag-in fermentation and storage, the taste of pickled mustard greens of the product is improved and the acidification process is accelerated; a compound spice that has a synergistic effect on the fermentation bacteria species during the fermentation process is screened and reasonably compounded, increasing the flavor of the finished product, making up for the deficiency of the inoculated fermentation fragrance, and at the same time inhibiting the growth of miscellaneous bacteria (especially the gas-producing miscellaneous bacteria), ensuring the quality stability of the product; a packaging bag made of a suitable material is screened to ensure its gas barrier property and water barrier property, avoiding the exchange of water and gas inside and outside the bag, especially avoiding the entry of external oxygen and activating the fermentation of aerobic microorganisms (especially yeasts), and maximizing the avoidance of the possibility of miscellaneous bacteria infection. It can further reduce the inoculation amount of the fermentation bacteria species synergistically under the condition of ensuring no contamination by miscellaneous bacteria. And no subsequent sterilization process is required.

[0103] Using bacteria to inhibit bacteria and using bags instead of jars, the bag-in fermentation pickled mustard greens process of the present invention optimizes and upgrades pickled mustard greens from traditional ancient brewing methods to a precise fermentation mode. The production process is simple, the process is convenient, the cost is low, the requirement for the site area is low, greatly improving the feasibility of industrial production of the product, and being more conducive to the industrialization, scale, and standardization development of the pickled mustard greens industry; while ensuring the taste and quality of the product, the formula is made clean (avoiding the addition of preservatives), enabling a wider market acceptance and providing significant health benefits, and having extremely strong practical guiding significance.

[0104] At this point, those skilled in the art recognize that although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and determined to cover all these other variations or modifications.

Claims

1. A preparation method of preservative-free pickled Chinese cabbage fermented in the bag, characterized in that, The preparation method comprises the following steps: Step S1: Pickled vegetable raw materials selection Remove impurities and inedible parts from fresh mustard greens, process them into the required shape and size, wash them and set them aside; Step S2: Raw material blanching and bacteria control pretreatment The mustard obtained in step S1 is blanched in a blanching solution containing calcium chloride to remove bacteria, and then taken out and cooled by strong cold air, and then put into a fermentation bag for later use; Step S3: Fermentation broth preparation According to the mass of mustard, weigh pure water, add appropriate amount of iodine-free salt and glucose, stir and boil to completely dissolve; add the composite spice water extract to the boiled mixture, stir evenly, add the composite fermentation agent after the liquid cools down, mix well and set aside; Step S4: Packaging The fermented liquid cooled in step S3 is quantitatively loaded into a fermentation bag and mixed with the mustard in step S2, vacuum-sealed, and placed in a cool place to dry; Step S5: Fermentation The vacuum-sealed fermentation bag obtained in step S4 is placed in a fermentation workshop to start fermentation until the pickled vegetables are fully mature.

2. The preparation method of a bagged fermented pickled Chinese cabbage without preservatives as described in claim 1, characterized in that, In step S2, the mass ratio of calcium chloride in the blanching solution is 0.1%-0.3%; the temperature of the blanching solution is 100°C boiling water, and the blanching time of the mustard is 1 min; the amount of the blanching solution is 8-10 times the mass of the mustard; and the water used for the blanching solution is tap water or groundwater that has undergone reverse osmosis.

3. The preparation method of a preservative-free pickled Chinese cabbage fermented in the bag as described in claim 1, characterized in that, The specific parameters of the strong cold air cooling in step S2 are: Wind speed 5~10 m / s, cooling time 10~15 min, cooling temperature 4~10℃, air filtration standard: based on "GB / T14295 Air Filter", use sub-high efficiency air filter, efficiency level is YG level, rated wind speed test rate ≥95%.

4. The preparation method of preservative-free pickled green vegetables fermented in the bag as described in claim 1, characterized in that, In step S3, the mass proportion of mustard, pure water, iodine-free salt, glucose, composite spices and composite fermentation bacteria is 30-60: 50-60: 4-4.5: 0.5-2: 0.6-1.4: 0.2-0.5; the pure water is tap water or groundwater that has been sterilized by reverse osmosis and ozone ultraviolet.

5. The preparation method of a preservative-free pickled Chinese cabbage fermented in the bag as described in claim 1, characterized in that, In the step S3, the compound fermentation bacterium agent is a combination of a direct-fed bacterium agent of Lactiplantibacillus plantarum and a direct-fed bacterium agent of Pediococcus acidilactici. The viable count of the direct-fed bacterium agent of Lactiplantibacillus plantarum is ≥ 10 10 CFU / g; the viable count of the direct-fed bacterium agent of Pediococcus acidilactici is ≥ 10 10 CFU / g; the configuration ratio of the direct-fed bacterium agent of Lactiplantibacillus plantarum and the direct-fed bacterium agent of Pediococcus acidilactici by viable count is 2 - 2.5:0.5 - 1.

6. The preparation method of a preservative-free fermented pakchoi in bag as described in claim 1, wherein In step S3, the composite spice is a combination of nutmeg, fennel, dill and caraway, wherein the mass fraction ratio of nutmeg, fennel, dill and caraway in the composite spice is 1.5-2:1.5-2:2.5-3:1-1.

5.

7. The preparation method of a bagged fermented pickled Chinese cabbage without preservatives as described in claim 1, characterized in that, In step S3, the composite fermentation agent is added when the liquid is cooled to 40-45°C.

8. The preparation method of preservative-free fermented pickled Chinese cabbage in bag according to claim 1, characterized in that, In step S4, the fermentation bag is a food packaging bag with an oxygen transmission rate (OTR) of < 1 cm 3 / m 2 ·24 h·atm and a water vapor transmission rate (WVTR) of < 1 g / m 2 ·24 h; the mass ratio of the fermentation broth to the mustard is 1:0.6 to 1.

9. The preparation method of preservative-free pickled green vegetables fermented in bags as described in claim 1, wherein The fermentation time in step S5 is 15 to 20 days.

10. A preservative-free pickled green vegetables fermented in the bag, characterized in that, The fermented pickled greens are prepared by any one of the preparation methods of claims 1-9.

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