High-crisp mustard green pickle and fermentation process thereof

Abstract

The application discloses a kind of high brittle green vegetable pickles and its fermentation process, belong to biological fermentation technology, a kind of high brittle green vegetable pickles, including the following raw materials: main material containing big leaf green vegetable, auxiliary material, crispness-keeping agent, composite ferment, brine;The main material includes big leaf green vegetable, garlic sprout, celery, and the mass ratio of big leaf green vegetable, garlic sprout, celery is 20:1:1;Composite ferment includes the first ferment, second ferment;First ferment includes leaf surface treatment agent and main ferment, the leaf surface treatment agent includes the following weight fraction components: 100 parts of zein, 8-10 parts of tannic acid, 2-3 parts of Tg enzyme, 20-25 parts of sodium caseinate modified nano calcium phosphate filler;The main ferment is direct-vision type ferment, and the addition amount is 0.02-0.03% of the total mass of main material;Second ferment is loaded bromelain's sea algae oligosaccharide.The application solves the problem that the leaf surface of big leaf green vegetable is large, and the fermentation degree of stem and leaf is inconsistent in the fermentation process.

Description

Technical Field

[0001] This invention belongs to the field of bio-fermentation technology and relates to a high-crisp green vegetable kimchi and its fermentation process. Background Technology

[0002] The large-leaf bok choy plant is highly adaptable and is one of the main raw materials for pickled vegetables. Pickled large-leaf bok choy is an excellent side dish, whether used to make sour soup fish, braised fish, or as a base for red and white soups.

[0003] However, due to the large leaf surface of Chinese cabbage, the fermentation of the stem and leaves is prone to uneven fermentation during the fermentation process. The leaves have a larger contact area with lactic acid bacteria and are easier to ferment than the stems. During the fermentation of kimchi, the leaves are prone to softening, while the stems may not be flavorful or have a bitter taste. Summary of the Invention

[0004] The purpose of this invention is to provide a crisp and crunchy pickled vegetable and its fermentation process, thereby solving the above-mentioned problems.

[0005] The technical solution adopted in this invention is as follows: A crispy pickled vegetable dish includes the following ingredients: a main ingredient containing large-leaf bok choy, auxiliary ingredients, a crisping agent, a compound fermentation agent, and brine; the main ingredient includes large-leaf bok choy, garlic sprouts, and celery, and the mass ratio of large-leaf bok choy, garlic sprouts, and celery is 20:1:1. The compound fermentation agent includes the first fermentation agent and the second fermentation agent; The first fermentation agent includes a foliar treatment agent and a main fermentation agent. The foliar treatment agent comprises the following components in parts by weight: 100 parts zein, 8-10 parts tannic acid, 2-3 parts Tg enzyme, and 20-25 parts sodium caseinate modified nano-calcium phosphate filler. The main fermentation agent is a direct-inoculation fermentation agent, added at 0.02-0.03% of the total mass of the main material. The second fermentation agent is an algae oligosaccharide loaded with bromelain (CAS No. 9001-00-7), wherein the enzyme activity of bromelain is ≥800U / mg and the amount of bromelain added is 1.2-1.8% of the amount of zein used.

[0006] Furthermore, the crisping agent includes perilla leaf extract microspheres and Sichuan pepper branch and leaf extract microspheres; wherein the amount of perilla leaf extract is 0.3% of the main ingredient mass; and the amount of Sichuan pepper branch and leaf extract is 0.2% of the main ingredient mass.

[0007] Furthermore, the seaweed oligosaccharide loaded with bromelain was prepared by the following method: seaweed oligosaccharide was dissolved in phosphate buffer solution with pH 6.0-6.5 to prepare a 6% (w / w) seaweed oligosaccharide solution. The solution was placed on a magnetic stirrer and stirred at a constant speed at 25°C. Bromelain was added, with a mass ratio of bromelain to seaweed oligosaccharide of 1:4. After the addition was completed, the solution was stirred at low speed at 20-25°C in the dark for 2 hours. Finally, alcohol precipitation was performed, the precipitate was collected, and the precipitate was dried and pulverized at low temperature to obtain the seaweed oligosaccharide loaded with bromelain.

[0008] Further, the auxiliary materials include a spice packet, white wine, and brown sugar; wherein, 1.3-1.5 ml of white wine is added per kilogram of main ingredient; 13-15 g of the spice packet is added per kilogram of main ingredient; and 3-5 g of brown sugar is added per kilogram of main ingredient; the components of the spice packet include dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root; wherein, the mass ratio of dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root is 5:1:1.5:0.5:0.3:0.2.

[0009] Further, the perilla leaf extract microspheres were prepared by the following method: dried perilla leaves were pulverized, sieved, and added to a 70% ethanol solution at a material-to-liquid ratio of 1:15. The mixture was refluxed at 75°C for 2 hours, filtered, and the filtrate was collected. The residue was extracted once more, and the two filtrates were combined. The ethanol in the filtrate was recovered by rotary evaporator, concentrated to a paste-like state, and freeze-dried to obtain perilla leaf extract powder. A 2.5% sodium alginate aqueous solution was prepared, and the perilla leaf extract powder was dispersed in deionized water to obtain a perilla leaf extract suspension. The perilla leaf extract suspension and sodium alginate aqueous solution were mixed at a mass ratio of 1:10 and stirred evenly to obtain a mixture. The mixture was added dropwise to a 3% calcium chloride solution, and the reaction was allowed to proceed for 40 minutes after the addition was completed. The mixture was then filtered and dried to obtain perilla leaf extract microspheres.

[0010] Further, the microspheres of *Zanthoxylum bungeanum* leaf and branch extract were prepared by the following method: dried *Zanthoxylum bungeanum* leaves and branches were pulverized, sieved, and added to a 60% ethanol solution at a material-to-liquid ratio of 1:20. The mixture was then ultrasonically extracted at 65°C for 45 minutes, filtered, and the filtrate was collected. The ethanol was recovered from the filtrate using a rotary evaporator, and the filtrate was concentrated to a paste-like state. After freeze-drying, *Zanthoxylum bungeanum* leaf and branch extract powder was obtained. A 3.5% sodium alginate aqueous solution was prepared, and the *Zanthoxylum bungeanum* leaf and branch extract powder was dispersed in deionized water to obtain a *Zanthoxylum bungeanum* leaf and branch extract powder suspension. The *Zanthoxylum bungeanum* leaf and branch extract powder suspension and the sodium alginate aqueous solution were mixed at a mass ratio of 1:15 and stirred evenly to obtain a mixture. A 5% calcium chloride solution was added dropwise to the mixture, and the mixture was cross-linked and cured for 60 minutes. The mixture was then filtered and dried to obtain *Zanthoxylum bungeanum* leaf and branch extract microspheres.

[0011] Furthermore, the sodium caseinate-modified nano-calcium phosphate filler is prepared by the following method: nano-calcium phosphate powder is added to a sodium caseinate solution with a mass fraction of 2%, the amount of nano-calcium phosphate powder added is 40% of the mass of sodium caseinate, after stirring evenly, it is treated with a high-speed shear emulsifier in a water bath at 50°C for 15 minutes, then the temperature is raised to 70°C and reacted for 2 hours, centrifuged, filtered, and freeze-dried to obtain the sodium caseinate-modified nano-calcium phosphate filler.

[0012] Furthermore, the amount of non-iodized salt added to the brine is 5-10% of the main ingredient mass, and 75 grams of salt are added to every 500 grams of mineral water or cooled boiled water.

[0013] Furthermore, the direct-inoculation fermentation agent comprises a compound lactic acid bacteria powder made from Lactobacillus plantarum 550 powder and Lactobacillus brucelli 225 powder in a mass ratio of 3:1, with a total viable count of (10... 10 ~10 12 ) CFU / g; among which, the preservation number of Lactobacillus plantarum 550 is CCTCC NO: M207202; and the preservation number of Lactobacillus bruneri 225 is CCTCC NO: M207203.

[0014] The fermentation process for a crisp and crunchy pickled vegetable includes the following steps: S1. Wash and drain the leafy greens, then soak them in a 15% salt solution for 3 days. After soaking, wash and drain them and set aside. Wash and drain the garlic sprouts and celery directly and set aside. S2. Preparation of the foliar treatment agent in the first fermentation agent: Dissolve zein in an ethanol solution. After complete dissolution, add tannic acid and Tg enzyme, and continue stirring for 10 minutes. Then add sodium caseinate modified nano-calcium phosphate filler and stir evenly to obtain the foliar treatment agent. Subsequently, immerse the leaves of the large-leafed Chinese cabbage in the foliar treatment agent for 20 minutes, then place them at 30°C for 1 hour, and then air dry at 40°C for 30 minutes to complete the foliar treatment of the large-leafed Chinese cabbage. After all the large-leafed Chinese cabbage used for fermentation has been immersed, detect the remaining amount of zein in the remaining foliar treatment agent. Record the amount of zein used based on the initial amount added and the remaining amount of zein. S3. Packing: Pack the large-leafed Chinese cabbage that has undergone leaf treatment into a jar, then add garlic sprouts, celery, auxiliary ingredients, and crisping agent in sequence. Next, add a direct-inoculation fermentation agent to the brine, stir well, pour the brine into the jar, cover the jar, add water along the rim of the jar, and place it in an environment of 18-20℃ to ferment for 5 days. After that, open the lid, add seaweed oligosaccharide loaded with bromelain (second fermentation agent), stir well, seal the lid, and place it in an environment of 18-20℃ to continue fermenting for 5-6 days. Then transfer it to an environment of 10℃ to continue fermenting for 2 days to obtain crispy Chinese cabbage kimchi.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The main fermenting agent in this invention, a high-crisp green vegetable kimchi, is a direct-inoculation fermenting agent, which, combined with the natural fermentation of the kimchi, provides the necessary conditions for the full fermentation of the large-leaf green vegetables. Furthermore, this application involves a leaf treatment agent and a second fermenting agent used in conjunction. The leaf treatment agent protects the leaves of the large-leaf green vegetables, preventing contact between the leaves and lactic acid bacteria, thus delaying leaf fermentation. After the stems of the large-leaf green vegetables have fermented for a period of time, the second fermenting agent hydrolyzes the leaf treatment agent, eliminating the protective layer on the leaves and exposing them to the kimchi brine to contact with the lactic acid bacteria, thus participating in fermentation. By controlling the order of fermentation time, the problem of inconsistent fermentation levels between the stems and leaves during the fermentation process is solved due to the large leaves of the large-leaf green vegetables. The fermented green vegetables have flavor in both stems and leaves, and both retain relative crispness. 2. In this invention, after the leaf treatment agent is hydrolyzed by the second fermentation agent, the product can serve as a nutrient for the growth of lactic acid bacteria, and can also promote the fermentation of green vegetables without affecting the quality of kimchi. 3. This invention ferments the kimchi at 18-20℃ for about 10 days and then transfers it to 10℃ for continued fermentation. This cooling method can effectively prevent over-fermentation in the later stages of fermentation, thus maintaining the color and crispness of the kimchi. 4. The crisping agent in this invention is perilla leaf extract microspheres and Sichuan pepper branch and leaf extract microspheres. Under the acidic conditions of fermentation, the perilla leaf extract microspheres and Sichuan pepper branch and leaf extract microspheres slowly and continuously release perilla leaf extract and Sichuan pepper branch and leaf extract, which can play a crisping effect on the stems and leaves of large-leafed Chinese cabbage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a product image of the crispy pickled green vegetables of this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0021] Example 1:

[0022] A preferred embodiment of the present invention provides a crispy pickled vegetable, comprising the following ingredients: a main ingredient containing large-leaf bok choy, auxiliary ingredients, a crisping agent, a compound fermentation agent, and brine; the main ingredient includes large-leaf bok choy, garlic sprouts, and celery, with a mass ratio of large-leaf bok choy, garlic sprouts, and celery of 20:1:1. The compound fermentation agent includes the first fermentation agent and the second fermentation agent; The first fermentation agent includes a foliar treatment agent and a main fermentation agent. The foliar treatment agent comprises the following components in parts by weight: 100 parts zein, 8 parts tannic acid, 2 parts Tg enzyme, and 20 parts sodium caseinate modified nano-calcium phosphate filler. The main fermentation agent is a direct-inoculation fermentation agent, added at 0.03% of the total mass of the main material. The second fermentation agent is seaweed oligosaccharide loaded with bromelain, wherein the enzyme activity of bromelain is 800 U / mg and the amount of bromelain added is 1.5% of the amount of zein used.

[0023] The crisping agent includes perilla leaf extract microspheres and Sichuan pepper branch and leaf extract microspheres; wherein, the amount of perilla leaf extract is 0.3% of the main ingredient mass; and the amount of Sichuan pepper branch and leaf extract is 0.2% of the main ingredient mass.

[0024] The seaweed oligosaccharide loaded with bromelain was prepared by the following method: seaweed oligosaccharide was dissolved in phosphate buffer solution with pH 6.5 to prepare a 6% (w / w) seaweed oligosaccharide solution. The solution was placed on a magnetic stirrer and stirred at a constant speed at 25°C. Bromelain was added, with a mass ratio of bromelain to seaweed oligosaccharide of 1:4. After the addition was completed, the solution was stirred at low speed at 25°C in the dark for 2 hours. Finally, alcohol precipitation was performed, the precipitate was collected, and the precipitate was dried and pulverized at low temperature to obtain the seaweed oligosaccharide loaded with bromelain.

[0025] The auxiliary materials include a spice packet, white wine, and brown sugar; wherein, 1.3-1.5 ml of white wine is added per kilogram of main ingredient; 13-15 g of spice packet is added per kilogram of main ingredient; and 3-5 g of brown sugar is added per kilogram of main ingredient; the components of the spice packet include dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root; wherein, the mass ratio of dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root is 5:1:1.5:0.5:0.3:0.2.

[0026] The perilla leaf extract microspheres were prepared by the following method: dried perilla leaves were pulverized, sieved, and added to a 70% ethanol solution at a material-to-liquid ratio of 1:15. The mixture was refluxed at 75°C for 2 hours, filtered, and the filtrate was collected. The residue was extracted once more, and the two filtrates were combined. The ethanol in the filtrate was recovered by rotary evaporation and concentrated to a paste-like state. The filtrate was then freeze-dried to obtain perilla leaf extract powder. A 2.5% sodium alginate aqueous solution was prepared, and the perilla leaf extract powder was dispersed in deionized water to obtain a perilla leaf extract suspension. The perilla leaf extract suspension and the sodium alginate aqueous solution were mixed at a mass ratio of 1:10 and stirred evenly to obtain a mixture. The mixture was added dropwise to a 3% calcium chloride solution. After the addition was completed, the mixture was reacted for 40 minutes, filtered, and dried to obtain perilla leaf extract microspheres.

[0027] The microspheres of *Zanthoxylum bungeanum* leaf and branch extract were prepared by the following method: dried *Zanthoxylum bungeanum* leaves and branches were pulverized, sieved, and added to a 60% ethanol solution at a material-to-liquid ratio of 1:20. The mixture was then extracted with ultrasound at 65°C for 45 minutes, filtered, and the filtrate was collected. The ethanol was recovered from the filtrate using a rotary evaporator, and the filtrate was concentrated to a paste-like consistency. After freeze-drying, *Zanthoxylum bungeanum* leaf and branch extract powder was obtained. A 3.5% sodium alginate aqueous solution was prepared, and the *Zanthoxylum bungeanum* leaf and branch extract powder was dispersed in deionized water to obtain a *Zanthoxylum bungeanum* leaf and branch extract powder suspension. The *Zanthoxylum bungeanum* leaf and branch extract powder suspension and the sodium alginate aqueous solution were mixed at a mass ratio of 1:15 and stirred until homogeneous to obtain a mixture. A 5% calcium chloride solution was added dropwise to the mixture, and the mixture was cross-linked and cured for 60 minutes. The mixture was then filtered and dried to obtain *Zanthoxylum bungeanum* leaf and branch extract microspheres.

[0028] The sodium caseinate-modified nano-calcium phosphate filler was prepared by the following method: nano-calcium phosphate powder was added to a sodium caseinate solution with a mass fraction of 2%, and the amount of nano-calcium phosphate powder added was 40% of the mass of sodium caseinate. After stirring evenly, the solution was treated with a high-speed shear emulsifier in a water bath at 50°C for 15 minutes, and then the temperature was raised to 70°C for 2 hours. After centrifugation, filtration, and freeze-drying, sodium caseinate-modified nano-calcium phosphate filler was obtained.

[0029] The amount of non-iodized salt added to the brine is 5-10% of the main ingredient mass, and 75 grams of salt are added to every 500 grams of mineral water or cooled boiled water.

[0030] The direct-inoculation starter culture comprises a compound lactic acid bacteria powder made from Lactobacillus plantarum 550 powder and Lactobacillus brucelli 225 powder in a mass ratio of 3:1, with a total viable count of (10) 10 ~10 12 ) CFU / g; among which, the preservation number of Lactobacillus plantarum 550 is CCTCC NO: M207202; and the preservation number of Lactobacillus bruneri 225 is CCTCC NO: M207203.

[0031] The fermentation process for a crisp and crunchy pickled vegetable includes the following steps: S1. Wash and drain the leafy greens, then soak them in a 15% salt solution for 3 days. After soaking, wash and drain them and set aside. Wash and drain the garlic sprouts and celery directly and set aside. S2. Preparation of the foliar treatment agent in the first fermentation agent: Dissolve zein in an ethanol solution. After complete dissolution, add tannic acid and Tg enzyme, and continue stirring for 10 minutes. Then add sodium caseinate modified nano-calcium phosphate filler and stir evenly to obtain the foliar treatment agent. Subsequently, immerse the leaves of the large-leafed Chinese cabbage in the foliar treatment agent for 20 minutes, then place them at 30°C for 1 hour, and then air dry at 40°C for 30 minutes to complete the foliar treatment of the large-leafed Chinese cabbage. After all the large-leafed Chinese cabbage used for fermentation has been immersed, detect the remaining amount of zein in the remaining foliar treatment agent. Record the amount of zein used based on the initial amount added and the remaining amount of zein. S3. Packing: Pack the large-leafed Chinese cabbage, after leaf treatment, into a jar. Then, add garlic sprouts, celery, auxiliary ingredients, and a crisping agent. Next, add a direct-inoculation fermentation agent to the brine, stir well, pour the brine into the jar, cover the jar, add water along the rim, and place it in an environment of 18℃ for 5 days to ferment. After that, open the lid, add seaweed oligosaccharides loaded with bromelain (second fermentation agent), stir well, seal the lid, and continue fermenting in an environment of 18℃ for 5 days. Then, transfer it to an environment of 10℃ for 2 more days to ferment, resulting in crispy Chinese cabbage kimchi. A picture of the kimchi is shown below. Figure 1 As shown.

[0032] Example 2:

[0033] Based on Example 1, this embodiment differs from Example 1 in that the first fermentation agent includes a leaf treatment agent and a main fermentation agent. The leaf treatment agent includes the following components in parts by weight: 100 parts zein, 9 parts tannic acid, 2.5 parts Tg enzyme, and 23 parts sodium caseinate modified nano-calcium phosphate filler.

[0034] Example 3:

[0035] Based on Example 1, this embodiment differs from Example 1 in that the first fermentation agent includes a foliar treatment agent and a main fermentation agent. The foliar treatment agent includes the following components in parts by weight: 100 parts zein, 10 parts tannic acid, 3 parts Tg enzyme, and 25 parts sodium caseinate modified nano-calcium phosphate filler.

[0036] Example 4:

[0037] This embodiment differs from Embodiment 2 in that the second fermenting agent in this embodiment is seaweed oligosaccharide loaded with bromelain, wherein the enzyme activity unit of bromelain is 800 U / mg and the amount of bromelain added is 1.2% of the amount of zein used.

[0038] Example 5:

[0039] This embodiment differs from Embodiment 2 in that the second fermenting agent in this embodiment is seaweed oligosaccharide loaded with bromelain, wherein the enzyme activity unit of bromelain is 800 U / mg and the amount of bromelain added is 1.8% of the amount of zein used.

[0040] Comparative Example 1 This comparative example differs from Example 2 in that the compound fermentation agent in this example only includes the direct-inoculation fermentation agent and does not include the foliar treatment agent or the second fermentation agent. All other aspects are the same.

[0041] Comparative Example 2 This comparative example is based on Example 2, except that the compound fermenting agent in this comparative example does not include a second fermenting agent. All other aspects are the same.

[0042] Comparative Example 3 This comparative example differs from Example 2 in that it does not contain tannic acid in its foliar treatment agent. All other aspects are identical.

[0043] Comparative Example 4 This comparative example differs from Example 2 in that it does not contain Tg enzyme in its foliar treatment agent. All other aspects are identical.

[0044] Comparative Example 5 This comparative example differs from Example 2 in that it does not include sodium caseinate-modified nano-calcium phosphate filler in its foliar treatment agent. All other aspects are identical.

[0045] Comparative Example 6 This comparative example differs from Example 2 in that the filler in the foliar treatment agent of this comparative example is not modified with sodium caseinate, but directly mixed with nano-calcium phosphate. All other aspects are the same.

[0046] Comparative Example 7 This comparative example differs from Example 2 in that the second fermentation agent in this comparative example does not contain seaweed oligosaccharides. All other aspects are the same.

[0047] Comparative Example 8 This comparative example is based on Example 2, but differs from Example 2 in that the preservative agent in this comparative example does not include perilla leaf extract microspheres.

[0048] Comparative Example 9 This comparative example is based on Example 2, but differs from Example 2 in that the crisping agent in this comparative example does not include microspheres of extract from the branches and leaves of Zanthoxylum bungeanum.

[0049] Comparative Example 10 This comparative example differs from Example 2 in that the crisping agent in this example includes perilla leaf extract and Sichuan pepper branch and leaf extract. Neither the perilla leaf extract nor the Sichuan pepper branch and leaf extract is treated with microspheres; they are added directly. All other aspects are the same.

[0050] Comparative Example 11 This comparative example differs from Example 2 in that the fermentation process for a crisp and crunchy pickled vegetable described in this comparative example includes the following steps: S1. Wash and drain the leafy greens, then soak them in a 15% salt solution for 3 days. After soaking, wash and drain them and set aside. Wash and drain the garlic sprouts and celery directly and set aside. S2. Preparation of the foliar treatment agent in the first fermentation agent: Dissolve zein in an ethanol solution. After complete dissolution, add tannic acid and Tg enzyme, and continue stirring for 10 minutes. Then add sodium caseinate modified nano-calcium phosphate filler and stir evenly to obtain the foliar treatment agent. Subsequently, immerse the leaves of the large-leafed Chinese cabbage in the foliar treatment agent for 20 minutes, then place them at 30°C for 1 hour, and then air dry at 40°C for 30 minutes to complete the foliar treatment of the large-leafed Chinese cabbage. After all the large-leafed Chinese cabbage used for fermentation has been immersed, detect the remaining amount of zein in the remaining foliar treatment agent. Record the amount of zein used based on the initial amount added and the remaining amount of zein. S3. Packing: Pack the large-leafed greens that have undergone leaf treatment into a jar, then add garlic sprouts, celery, auxiliary ingredients, and crisping agent in sequence. Next, add a direct-inoculation fermentation agent to the brine, stir well, pour the brine into the jar, cover the jar, add water along the rim of the jar, and place it in an environment of 18℃ to ferment for 12 days to obtain pickled greens.

[0051] Experimental Example 1 Based on existing technology, sensory tests were conducted to examine the color, aroma, texture, and taste of the pickled vegetables prepared in Examples 1-5 and Comparative Examples 1-11. The results are shown in Table 1.

[0052] Table 1 Sensory test results of pickled vegetables

[0053] Experimental Example 2 According to the National Food Safety Standard "Limits of Contaminants in Food (GB2762-2022)," the nitrite content of the pickled vegetables in Examples 1-5, Comparative Examples 1, 3, 4, 6, 7, and 10 was tested to determine whether it met the standard. The National Food Safety Standard "Limits of Contaminants in Food (GB2762-2022)" stipulates that the nitrite content should not exceed 20 mg / kg. The detection method for nitrite content is existing technology. The results of whether it meets the standard are shown in Table 2.

[0054] Table 2. Detection results of nitrite content in kimchi

[0055] Experimental Example 3 The number of lactic acid bacteria and pathogenic bacteria in the kimchi in Examples 1-5 were tested according to the National Food Safety Standard for Microbiological Examination of Food (GB 4789.35-2023) and the National Food Safety Standard for Limits of Pathogenic Bacteria in Food (GB 29921-2013). The test methods were existing technologies, and the results are shown in Table 3.

[0056] Table 3. Microbiological test results of kimchi

[0057] Based on the data in Tables 1-3, it can be seen that the kimchi in this embodiment of the invention is free of pathogenic bacteria and contains a high level of lactic acid bacteria. The pH of the kimchi brine is 4.3-4.9, and the resulting kimchi has low nitrite levels, meeting the requirements for kimchi and exhibiting good overall sensory effects. The kimchi brine of this invention can be reused twice; even after this, the lactic acid bacteria content in the kimchi brine can still reach 10%. 6 -10 8 CFU / mL.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A type of crisp and crunchy pickled vegetable, characterized in that: The ingredients include: main ingredients containing large-leaf bok choy, auxiliary ingredients, crisping agent, compound fermentation agent, and brine; the main ingredients include large-leaf bok choy, garlic sprouts, and celery, with a mass ratio of large-leaf bok choy, garlic sprouts, and celery of 20:1:

1. The compound fermentation agent includes a first fermentation agent and a second fermentation agent; The first fermentation agent includes a foliar treatment agent and a main fermentation agent. The foliar treatment agent comprises the following components in parts by weight: 100 parts zein, 8-10 parts tannic acid, 2-3 parts Tg enzyme, and 20-25 parts sodium caseinate modified nano-calcium phosphate filler. The main fermentation agent is a direct-inoculation fermentation agent, added at 0.02-0.03% of the total mass of the main material. The second fermentation agent is seaweed oligosaccharide loaded with bromelain, wherein the enzyme activity of bromelain is ≥800 U / mg and the amount of bromelain added is 1.2-1.8% of the amount of zein used; The fermentation process of crisp and crunchy green vegetable kimchi based on compound fermentation agents includes the following steps: S1. Wash and drain the leafy greens, then soak them in a 15% salt solution for 3 days. After soaking, wash and drain them and set aside. Wash and drain the garlic sprouts and celery directly and set aside. S2. Preparation of the foliar treatment agent in the first fermentation agent: Dissolve zein in an ethanol solution. After complete dissolution, add tannic acid and Tg enzyme, and continue stirring for 10 minutes. Then add sodium caseinate modified nano-calcium phosphate filler and stir evenly to obtain the foliar treatment agent. Subsequently, immerse the leaves of the large-leafed Chinese cabbage in the foliar treatment agent for 20 minutes, then place them at 30°C for 1 hour, and then air dry them at 40°C for 30 minutes to complete the foliar treatment of the large-leafed Chinese cabbage. After all the large-leafed Chinese cabbage used for fermentation has been immersed, detect the remaining amount of zein in the remaining foliar treatment agent. Record the amount of zein used based on the initial amount added and the remaining amount of zein. S3. Packing: Pack the large-leafed Chinese cabbage that has undergone leaf treatment into a jar, then add garlic sprouts, celery, auxiliary ingredients, and crisping agent in sequence. Next, add a direct-inoculation fermentation agent to the brine, stir well, pour the brine into the jar, cover the jar, add water along the rim of the jar, and place it in an environment of 18-20℃ to ferment for 5 days. After that, open the lid, add seaweed oligosaccharide loaded with bromelain, stir well, seal the lid, and continue to ferment for 5-6 days. Then transfer it to an environment of 10℃ to continue fermenting for 2 days to obtain high-crisp Chinese cabbage kimchi. The crisping agent comprises perilla leaf extract microspheres and Sichuan pepper branch and leaf extract microspheres; wherein, the amount of perilla leaf extract is 0.3% of the main ingredient mass; and the amount of Sichuan pepper branch and leaf extract is 0.2% of the main ingredient mass. The sodium caseinate-modified nano-calcium phosphate filler was prepared by the following method: nano-calcium phosphate powder was added to a sodium caseinate solution with a mass fraction of 2%, and the amount of nano-calcium phosphate powder added was 40% of the mass of sodium caseinate. After stirring evenly, the solution was treated with a high-speed shear emulsifier in a water bath at 50°C for 15 minutes, and then the temperature was raised to 70°C for 2 hours. After centrifugation, filtration, and freeze-drying, sodium caseinate-modified nano-calcium phosphate filler was obtained.

2. The crisp and crunchy pickled vegetables according to claim 1, characterized in that: The seaweed oligosaccharide loaded with bromelain was prepared by the following method: seaweed oligosaccharide was dissolved in phosphate buffer solution with pH 6.0-6.5 to prepare a 6% (w / w) seaweed oligosaccharide solution. The solution was placed on a magnetic stirrer and stirred at a constant speed at 25°C. Bromelain was added, with a mass ratio of bromelain to seaweed oligosaccharide of 1:

4. After the addition was completed, the solution was stirred at a low speed at 20-25°C in the dark for 2 hours. Finally, alcohol precipitation was performed, the precipitate was collected, and the precipitate was dried and pulverized at low temperature to obtain the seaweed oligosaccharide loaded with bromelain.

3. The crisp and crunchy pickled vegetables according to claim 1, characterized in that: The auxiliary materials include a spice packet, white wine, and brown sugar; wherein, 1.3-1.5 ml of white wine is added per kilogram of main ingredient; 13-15 g of spice packet is added per kilogram of main ingredient; and 3-5 g of brown sugar is added per kilogram of main ingredient; the components of the spice packet include dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root; wherein, the mass ratio of dried red chili peppers, white fungus, Sichuan peppercorns, star anise, licorice root, and angelica root is 5:1:1.5:0.5:0.3:0.

2.

4. The crisp and crunchy pickled vegetables according to claim 1, characterized in that: The perilla leaf extract microspheres were prepared by the following method: dried perilla leaves were pulverized, sieved, and added to a 70% ethanol solution at a material-to-liquid ratio of 1:

15. The mixture was refluxed at 75°C for 2 hours, filtered, and the filtrate was collected. The residue was extracted once more, and the two filtrates were combined. The ethanol in the filtrate was recovered by rotary evaporation and concentrated to a paste-like state. The filtrate was then freeze-dried to obtain perilla leaf extract powder. A 2.5% sodium alginate aqueous solution was prepared, and the perilla leaf extract powder was dispersed in deionized water to obtain a perilla leaf extract suspension. The perilla leaf extract suspension and the sodium alginate aqueous solution were mixed at a mass ratio of 1:10 and stirred evenly to obtain a mixture. The mixture was added dropwise to a 3% calcium chloride solution. After the addition was completed, the mixture was reacted for 40 minutes, filtered, and dried to obtain perilla leaf extract microspheres.

5. The crisp and crunchy pickled greens according to claim 1, characterized in that: The microspheres of *Zanthoxylum bungeanum* leaf and branch extract were prepared by the following method: dried *Zanthoxylum bungeanum* leaves and branches were pulverized, sieved, and added to a 60% ethanol solution at a material-to-liquid ratio of 1:

20. The mixture was then extracted with ultrasound at 65°C for 45 minutes, filtered, and the filtrate was collected. The ethanol was recovered from the filtrate using a rotary evaporator, and the filtrate was concentrated to a paste-like consistency. After freeze-drying, *Zanthoxylum bungeanum* leaf and branch extract powder was obtained. A 3.5% sodium alginate aqueous solution was prepared, and the *Zanthoxylum bungeanum* leaf and branch extract powder was dispersed in deionized water to obtain a *Zanthoxylum bungeanum* leaf and branch extract powder suspension. The *Zanthoxylum bungeanum* leaf and branch extract powder suspension and the sodium alginate aqueous solution were mixed at a mass ratio of 1:15 and stirred until homogeneous to obtain a mixture. A 5% calcium chloride solution was added dropwise to the mixture, and the mixture was cross-linked and cured for 60 minutes. The mixture was then filtered and dried to obtain *Zanthoxylum bungeanum* leaf and branch extract microspheres.

6. The crisp and crunchy pickled vegetables according to claim 1, characterized in that: The amount of non-iodized salt added to the brine is 5-10% of the main ingredient mass, and 75 grams of salt are added to every 500 grams of mineral water or cooled boiled water.

7. The crisp and crunchy pickled vegetables according to claim 1, characterized in that: The direct-inoculation starter culture comprises a compound lactic acid bacteria powder made from Lactobacillus plantarum 550 powder and Lactobacillus brucelli 225 powder in a mass ratio of 3:1, with a total viable count of (10) 10 ~10 12 ) CFU / g; among which, the preservation number of Lactobacillus plantarum 550 is CCTCC NO: M207202; and the preservation number of Lactobacillus bruneri 225 is CCTCC NO: M207203.

8. The fermentation process for a high-crisp green vegetable kimchi according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Wash and drain the leafy greens, then soak them in a 15% salt solution for 3 days. After soaking, wash and drain them and set aside. Wash and drain the garlic sprouts and celery directly and set aside. S2. Preparation of the foliar treatment agent in the first fermentation agent: Dissolve zein in an ethanol solution. After complete dissolution, add tannic acid and Tg enzyme, and continue stirring for 10 minutes. Then add sodium caseinate modified nano-calcium phosphate filler and stir evenly to obtain the foliar treatment agent. Subsequently, immerse the leaves of the large-leafed Chinese cabbage in the foliar treatment agent for 20 minutes, then place them at 30°C for 1 hour, and then air dry them at 40°C for 30 minutes to complete the foliar treatment of the large-leafed Chinese cabbage. After all the large-leafed Chinese cabbage used for fermentation has been immersed, detect the remaining amount of zein in the remaining foliar treatment agent. Record the amount of zein used based on the initial amount added and the remaining amount of zein. S3. Packing: Pack the large-leafed Chinese cabbage that has undergone leaf treatment into a jar, then add garlic sprouts, celery, auxiliary ingredients, and crisping agent in sequence. Next, add a direct-inoculation fermentation agent to the brine, stir well, pour the brine into the jar, cover the jar, add water along the rim of the jar, and place it in an environment of 18-20℃ to ferment for 5 days. After that, open the lid, add seaweed oligosaccharide loaded with bromelain, stir well, seal the lid, and continue to ferment for 5-6 days. Then transfer it to an environment of 10℃ to continue fermenting for 2 days to obtain high-crisp Chinese cabbage kimchi.

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