CN105533571A - Vegetable pickling method for restraining generation of nitrite and pellicle in pickling process - Google Patents

Abstract

The invention relates to a vegetable pickling method for inhibiting the formation of nitrite and bacteria during the salting process. The purpose is to provide a method that has positive significance for pollution control, emission reduction, clean processing and sustainable development of the pickled vegetable industry in my country. The technical solution is: a vegetable pickling method for inhibiting the formation of nitrite and bacteria during salting, which is carried out according to the following steps: (1) preparation of a salting pool; (2) preparation of a starter; (3) pickling Pretreatment of raw materials; (4) preparation of film bags; (5) salting; (6) sealing and gas regulation; (7) storage and management.

Description

A pickling method for inhibiting the formation of nitrite and bacteria during salt pickling

technical field

The invention relates to the technical field of vegetables salted and fermented food, in particular to a vegetable pickling method which uses carbon dioxide and other gas control technologies to suppress the formation of bacteria and nitrite during the salting process.

Background technique

China is the world's largest producer of vegetables and there are many varieties of processed vegetables. Salted vegetables are an important method of vegetable processing in my country. The salting process is completed by the osmosis of salt, the fermentation of microorganisms, the decomposition of proteins, and a series of complex biochemical processes in vegetables.

The salting process of pickled vegetables is the fermentation process of lactic acid bacteria. The main product is lactic acid, and the incidental products mainly include esters, amino acids and other organic acids. These products are essential for the formation of the unique flavor and nutrition of salted vegetables. Pickled vegetables are easy to produce nitrite during the salting process, and excessive nitrite affects people's physical and mental health, and its harm to the human body has attracted more and more attention. The harm of nitrite to the human body mainly has two aspects. On the one hand, it causes methemoglobinemia in the human body and causes acute poisoning; on the other hand, it is the precursor of N-nitroso compounds, which increases the risk of carcinogenesis. Therefore, controlling the formation of nitrite during the salting process of pickled vegetables is of vital significance to improve the safety of vegetable fermented food.

In addition, since pickled vegetables are mostly salted through the traditional fermentation process, they are easily invaded by bacteria in the air. During the open salting fermentation or storage process, if the container is not strictly sealed, or if it is placed in a closed container but not filled, air will enter the fermentation liquid, which will increase the dissolved oxygen in the fermentation liquid, and the film-forming yeast will Rapidly grow and multiply on the surface of the fermentation broth to form bacteria. When the fungus begins to form, it only grows a ring film along the wall of the barrel, and then grayish white or light yellow dots appear on the surface of the fermentation liquid, forming small truffles. At the beginning, the fungus was light and thin, and then gradually thickened. There are many wrinkles on the membrane, and the liquid surface is completely covered. With a slight vibration, the membrane is broken, and it is divided into a number of white small pieces or particles that sink, making the fermentation liquid turbid. After a long time, the taste will deteriorate. The untouched fungus grows up gradually, several small pieces connect together, grow from the edge to the center, and finally form a thick and wrinkled fungus film. It has been proved by microbiological examination that the biofilm is a microbial composition mainly composed of yeast, that is, film-producing yeast. Membrane-forming yeast is a kind of harmful yeast. The production of a large amount of bacteria will not only give salted vegetables a "bacteria" taste, but also affect the appearance during pickling, which is disgusting, affects appetite, and makes the fermentation liquid turbid. More importantly, when salted vegetables are pickled under the condition of being exposed to the air, the mass reproduction of film-forming yeast will not only decompose the organic matter in the salted vegetable tissue, but also decompose the Nutrients such as lactic acid and other esters, so that the acidity of salted vegetable products will decrease and spoilage, affecting the quality and flavor of salted vegetable products, directly affecting product quality and economic benefits.

Contents of the invention

The purpose of the present invention is to form a large amount of bacteria on the surface of the pickling solution even if the traditional pickled vegetables are pickled with high salt and high osmotic pressure, which will affect the appearance of the pickling period, cause the fermentation solution to be turbid, and affect the quality of pickled vegetables. The generation of high content of nitrite and other disadvantages, on the basis of lower salt consumption (7%), provides a way to inhibit the generation of pickle liquid bacteria and nitrite through gas regulation, in order to improve our country's traditional The technology of salted vegetables provides new ideas and methods, which is of positive significance to the pollution control and emission reduction, clean processing and sustainable development of my country's pickled vegetable industry.

For realizing the purpose of the present invention, the present invention is achieved through the following technical solutions:

A method of pickling vegetables for inhibiting the generation of nitrite and bacteria in the salting process is carried out according to the following steps:

(1) Preparation of the saline pond: dig a 3-5×2-4×1-2m saline pond under the ground, and make leak-proof treatment; spare.

(2) Preparation of starter: culture Lactobacillus casei and Lactobacillus plantarum and collect the bacteria sludge at the bottom, then mix bacteria sludge, skimmed milk, maltodextrin, three The polyphosphate is freeze-dried after being stirred, and is set aside;

(3) Pretreatment of pickled vegetable raw materials: the harvested vegetables are patted clean of soil, exposed to the sun until the moisture is reduced by 20-30%, bundled into bundles, weighed, and set aside;

(4) Film bag preparation: According to the size of the salted pool, select an EVOH film bag with one end open, punch a hole at the lower edge of the opening and install an inflation and exhaust switch, and put the film bag into the back pocket of the salted pool 100-120cm higher than the saline pool, for standby;

(5) Salting: Sprinkle a thin layer of salt and a small amount of starter described in step (4) on the bottom of the film bag, and salt according to the stacking mode of one layer of vegetables and one layer of salt, and sprinkle once for each layer of vegetables Sprinkle salt, one foot salt, one leavening agent and sugar substances, sprinkle a small amount of water before salt throwing, sprinkle salt first, sprinkle foot salt after stepping vegetables, the ratio of throwing salt to foot salt is the amount of salt used for each layer of vegetables 7:3; the parts by weight of pickled vegetables, edible salt, starter and carbohydrates are 100:6-8:0.4-0.6:0.8-1.2, wherein 20% of edible salt is reserved as noodle salt; The body is covered with a layer of plastic film, and stones are placed on the shelf for pressure; the weight ratio of vegetables to stones is 1:0.08-0.1;

(6) Sealing and gas regulation: heat and seal the mouth of the VOH film bag above the saline pool with a heat sealer; connect the charge and exhaust switch with a vacuum pump, extract the air in the EVOH film bag and fill it with bacteriostatic gas, Repeat several times until the pressure in the bag reaches 0.06MPa and the purity of the antibacterial gas reaches 95%-98%, then turn off the inflation and exhaust switch until it is completely sealed;

(7) Storage and management: regularly check the gas purity and pressure in the EVOH film bag, and replenish in time if the gas purity is lower than 90% or the pressure is lower than 0.04MPa; until the salting process ends.

The pickled vegetable raw materials refer to potherb mustard, Chinese cabbage, celery, mustard greens, bracken, basil, green cabbage, lettuce, Jerusalem artichoke, ginger, cabbage, garlic, onion, mustard, kohlrabi, turnip, radish, Lotus root, water chestnut, pepper, cucumber, wild rice stem, wax gourd, cowpea, sword bean, matsutake, bamboo shoots.

The Lactobacillus casei and Lactobacillus plantarum are all cited from CGMCC, General Microbiology Center of China Committee for Culture Collection of Microorganisms, with numbers 1.0029 and 1.0556, respectively.

The sugar substance refers to a mixture of one or more of glucose, fructose, sucrose and galactose in any proportion.

The anti-leak treatment of the step (1) is to smooth the surface of the pool with cement, inlay acid and alkali-resistant white ceramic tiles, and finally fill it with water to see if it leaks.

The bacteria slime in the step (2) is made by mixing Lactobacillus casei and Lactobacillus plantarum at a high density of 35°C for 36-48 hours and then mixing them at a ratio of 1:1, and then mixing them at a speed of 4000 rpm at 0-5°C. Freeze and centrifuge for 15 minutes; the freeze-drying method is to stir the bacteria slime, skimmed milk, maltodextrin, and tripolyphosphate at -55--60°C for 48-72 hours, and use EVOH film bags to vacuum pack and avoid light. Store at a temperature of 0-5°C.

The sun-drying of the described step (3) is to flatten the harvested vegetables on the spot, and let them cool and dry for 2-4 hours under natural sunlight, during which time prevent from getting drenched in rain.

During the salting of the step (5), arrange the arranged dishes vertically from the four sides to the center in a spiral manner, the leaves of the first layer of vegetables at the bottom face down, and the roots face up, and the roots of the second layer start to face down, and the leaves face up. The arrangement should be uniform in thickness; when salting, sprinkle salt every time, and turn from the four sides to the center according to the direction of the arrangement of vegetables.

The antibacterial gas in the step (6) is one of carbon dioxide, nitrogen, helium and argon.

The installation of the charging and exhausting switch is to open a hole with a diameter of 2-3mm on the EVOH film bag, and the filling and exhausting nozzle passes through the hole and is tightly sealed with a sealing gasket. The gasket is coated with AB glue, and the latex tube is sealed. It is connected with the inflation and exhaust nozzle, and the connection is reinforced with a fastening piece, and the other end of the latex tube is tightly sealed by a screw water stop valve.

The beneficial effects of the present invention are:

One, the high concentration of antibacterial gas has affected the growth of film-producing yeasts such as Hansen Debari, and delayed the logarithmic growth phase of the growth of film-producing yeasts such as Hansen Debari; thus although the amount of salt is only 7%, the stain There is no "bacteria" on the surface of the liquid, and the pickling liquid is clear and transparent.

2. During the preservation period, the total number of microbial colonies and acidity of pickled vegetables decreased significantly, and the vegetables were bright yellow in color, with the unique fragrance of pickled vegetables, delicious and crisp.

3. The nitrite content of pickled vegetables decreased significantly during the storage period, and the nitrite content did not exceed 2mg/kg until the sixth month of storage.

4. Changed our country’s traditional pickled vegetables relying on high salt (salt content as high as 15% or more), high osmotic pressure and other pickling methods, reducing the large discharge of high-salt brine and causing black and odorous water bodies, soil compaction and salinization to the environment Low-salt salting also reduces the desalination and dehydration processes in the processing of pickled vegetables, reduces the cost, reduces the loss of nutrients in pickled vegetables and the threat of high-salt food to human health, in order to improve the process of traditional salted vegetables in my country Provides new ideas and methods.

Description of drawings

Figure 1 is a schematic diagram of salting pickled vegetables.

detailed description

The EVOH film bag of the present invention refers to the production of ethylene/vinyl alcohol copolymer, which has excellent barrier properties, transparency, gloss, mechanical strength, stretchability, wear resistance, cold resistance and High barrier film bag with strong surface strength.

The present invention will be further illustrated by the following examples, but it should be understood that the present invention is not limited by these contents.

Example 1:

(1) Preparation of the saline pool: dig a 5×4×2m saline pool under the ground, smooth the surface of the pool with cement, inlaid with acid and alkali resistant white tiles, and finally fill it with water to see if there is any leakage; set aside.

(2) Preparation of starter: Lactobacillus casei and Lactobacillus plantarum were cultured at a high density at 35°C for 36 hours, then mixed in a ratio of 1:1, and centrifuged at 5°C for 15 minutes at a speed of 4000 rpm to collect the bottom Bacteria slime, add skim milk, maltodextrin, tripolyphosphate, the weight ratio of the bacteria slime and skim milk, maltodextrin, tripolyphosphate is 100:15:5:1, stir well and mix with -55℃ Freeze-dried for 56 hours, vacuum-packed in EVOH high-barrier film bags, and stored in the dark at a temperature of 0-5°C. spare.

(3) Pretreatment of pickled vegetable raw materials: pat the harvested potherb mustard clean the soil, spread it on the spot, and let it cool in the natural sunlight for 2 hours. During this period, prevent from raining. When the moisture is reduced by 20%, bundle them into bundles and weigh them spare;

(4) Preparation of film bag: According to the size of the salting pool, order a film bag of 6×5×3m. The material of the film bag is EVOH, a high-barrier material. The top of the film bag is opened, and the lower edge of the opening is punched before installation A charge and discharge switch with high sealing performance. Sprinkle a small amount of water around the salting pond, put the film bag into the salting pond and fully open the mouth of the bag, the mouth of the EVOH film bag is 100cm higher than the salting pond, and set aside.

(5) Salting: Sprinkle a thin layer of salt and a small amount of starter on the bottom of the film bag, and then arrange the arranged vegetables vertically in a spiral from the four sides to the center. From the second layer, the roots face down and the leaves face up, and the arrangement is uniform in thickness. Carry out salting according to the stacking mode of one layer of vegetables and one layer of salt. For each layer of vegetables, sprinkle salt and foot salt once. The ratio of salt to foot salt is 7:3 of the amount of salt used in each layer of vegetables. Sprinkle the fermenting agent and sugar substance described in step (2) after sprinkling the foot salt, the parts by weight of pickled vegetables, edible salt, fermenting agent and sugar substance are 100:7:0.5:1, and 20% of them are reserved of edible salt is used as flour salt. Every time you sprinkle salt, follow the direction of the arrangement of vegetables from the four sides to the center. Finally, cover the potherb mustard body with a layer of plastic film, arrange the bamboo slices in the shape of a well on the rack, and place stones on it according to the weight ratio of potherb mustard and stone at a ratio of 1:0.08 for pressurization.

(6) Sealing and gas regulation: Heat and seal the mouth of the VOH film bag above the saline pool with a heat sealer; use a vacuum pump to connect with the filling and exhausting switch provided on the film bag, and pull out the EVOH bag after opening the switch Repeat this several times until the pressure in the EVOH bag reaches 0.06MPa and the purity of carbon dioxide reaches 98%, then tighten the carbon dioxide bottle, and use the water stop valve to clamp the charging and exhausting switch on the EVOH bag latex tubing until completely sealed. Such as schematic diagram 1.

(7) Storage and management: Regularly check the purity and pressure of carbon dioxide in the EVOH high barrier bag, and replenish carbon dioxide in time when leakage is found, the purity is lower than 90%, or the pressure is lower than 0.04MPa; until the salting process is over.

Example 2:

In this example, step (1) pickled vegetable salting container is a pottery jar, and 70% of the jar body is buried in the ground, and the jar is cleaned and dried; the Chinese cabbage harvested in the sun is cool and dried for 4 hours, and the moisture is reduced by 30%. The parts by weight of pickled vegetables and edible salt are 100:7.5. The pottery jar is divided into three parts: the bottom, the middle of the jar and the upper part of the jar. 10-15% of the average number, the remaining salt is added to the top of the cylinder, soaked with cover salt; all the other process steps are the same as in embodiment 1.

Example 3:

In this example, step (5) extracts the air in the EVOH bag and fills it with gas, so it is repeated several times until the bacteriostatic gas purity in the EVOH bag reaches 95%. switch; the rest of the process steps are the same as in embodiment 1. The bacteriostatic gas described in this example is nitrogen.

Example 4:

In this example, the pickling raw material of step (2) is radish, and the salting container is a pottery jar. After drying the radish for 4 hours, put the raw material and edible salt in a ratio of 100:3 by weight and salt it in a tank. Place stones for pressurization, and the salting will end after 3 to 5 days. Take the salted radish out of the cylinder and dry it for 24-48 hours until the original weight is reduced by 25-30%. Then, carry out the second salting according to the method described above, and the parts by weight of radish and edible salt are 100:2 After 5-7 days of salting, go out of the cylinder to dry and finish, and carry out salting according to step (4), the parts by weight of radish and edible salt are 100:2; all the other process steps are the same as in Example 1. The raw materials of pickles described in this example can be replaced with green cabbage heads.

Example 4:

In this example, the salting container in step (1) is a plastic bucket, and the raw material for pickling vegetables in step (2) is bamboo shoots. Cut the bamboo shoots off the bamboo shoots, cut the shells of the bamboo shoots and peel them off, split the bamboo shoots into 3-4 pieces and put them in a container filled with clear water; step (4) is salted with salt water, the weight fraction of the bamboo shoots, water and salt The ratio is 100:70:7; after the salt water is prepared, put it in the container and stir until the salt is completely melted; put a high-barrier EVOH plastic bag in the salted container, and the mouth of the EVOH plastic bag is 80cm higher than the mouth of the plastic barrel , put the bamboo shoots in a plastic bag, pour salt water into the plastic barrel immediately to 20cm, cover with a layer of plastic film, put a well-shaped bamboo piece on it, and place it on it according to the weight ratio of bamboo shoots and stones: 1:0.08 Stone is pressed; All the other processing steps are the same as embodiment 1.

Claims (10)

1. a method for pickling vegetables suppressing nitrite and bacterium in the process of salting, carried out as follows: (1) Preparation of the saline pond: dig a 3-5×2-4×1-2m saline pond under the ground, and make leak-proof treatment; spare. (2) Preparation of starter: culture Lactobacillus casei and Lactobacillus plantarum and collect the bacteria sludge at the bottom, then mix bacteria sludge, skimmed milk, maltodextrin, three The polyphosphate is freeze-dried after being stirred, and is set aside; (3) Pretreatment of pickled vegetable raw materials: the harvested vegetables are patted clean of soil, exposed to the sun until the moisture is reduced by 20-30%, bundled into bundles, weighed, and set aside; (4) Film bag preparation: According to the size of the salted pool, select an EVOH film bag with one end open, punch a hole at the lower edge of the opening and install an inflation and exhaust switch, and put the film bag into the back pocket of the salted pool 100-120cm higher than the saline pool, for standby; (5) Salting: Sprinkle a thin layer of salt and a small amount of starter described in step (4) on the bottom of the film bag, and salt according to the stacking mode of one layer of vegetables and one layer of salt, and sprinkle once for each layer of vegetables Sprinkle salt, one foot salt, one leavening agent and sugar substances, sprinkle a small amount of water before salt throwing, sprinkle salt first, sprinkle foot salt after stepping vegetables, the ratio of throwing salt to foot salt is the amount of salt used for each layer of vegetables 7:3; the parts by weight of pickled vegetables, edible salt, starter and carbohydrates are 100:6-8:0.4-0.6:0.8-1.2, wherein 20% of edible salt is reserved as noodle salt; The body is covered with a layer of plastic film, and stones are placed on the shelf for pressure; the weight ratio of vegetables to stones is 1:0.08-0.1; (6) Sealing and gas regulation: heat and seal the mouth of the VOH film bag above the saline pool with a heat sealer; connect the charge and exhaust switch with a vacuum pump, extract the air in the EVOH film bag and fill it with bacteriostatic gas, Repeat several times until the pressure in the bag reaches 0.06MPa and the purity of the antibacterial gas reaches 95%-98%, then turn off the inflation and exhaust switch until it is completely sealed; (7) Storage and management: regularly check the gas purity and pressure in the EVOH film bag, and replenish in time if the gas purity is lower than 90% or the pressure is lower than 0.04MPa; until the salting process ends. 2. the method for pickled vegetables that suppresses the generation of nitrite and bacterium in the salting process according to claim 1, is characterized in that described pickled vegetables raw material refers to potherb mustard, Chinese cabbage, celery, mustard greens, bracken, purple Su, green cabbage, lettuce, Jerusalem artichoke, ginger, cabbage, garlic, onion, mustard, kohlrabi, turnip, radish, lotus root, water chestnut, pepper, cucumber, water bamboo, winter melon, cowpea, sword bean, matsutake, bamboo shoots. 3. in the salting process according to claim 1, suppress the pickling method that nitrite and bacterium fertilization generate, it is characterized in that described Lactobacillus casei (LactobacillusCasei), plant Lactobacillus (Lactobacillusplantarum), all quote from China General Microbiology Center CGMCC of Microbiological Culture Collection Management Committee, the numbers are 1.0029 and 1.0556 respectively. 4. the method for pickling vegetables suppressing nitrite and bacterium generation in the salting process according to claim 1, is characterized in that described carbohydrate substance refers to a kind of in glucose, fructose, sucrose and galactose or A variety of mixtures in any proportion. 5. according to claim 2 or 3 or the method for pickling vegetables that suppresses nitrite and bacteria in the salting process described in claim 4, it is characterized in that the anti-leakage treatment of described step (1) is to use cement on the pond surface Smooth it out, inlay it with acid and alkali-resistant white tiles, and finally fill it with water to see if it leaks. 6. according to claim 5, in the salting process, suppress nitrite and the method for pickling vegetables produced by bacteria, it is characterized in that the bacterium slime of described step (2) is that Lactobacillus casei and Lactobacillus plantarum are processed through 35 After high-density culture at ℃ for 36-48 hours, it is mixed according to the ratio of 1:1, and then obtained by refrigerated centrifugation at 0-5 ℃ for 15 minutes at a speed of 4000 rpm; 1. Stir tripolyphosphate and freeze-dry at -55--60°C for 48-72h, vacuum pack in EVOH film bag, and store at 0-5°C away from light. 7. according to claim 6, in the salting process, suppress the method for pickling vegetables that nitrite and bacterium are produced, it is characterized in that the solarization of described step (3) is that the vegetables harvested are flattened on the spot, and natural sunlight Keep in the sun for 2-4 hours, avoiding rain during the period. 8. The method for pickling vegetables that suppresses the generation of nitrite and bacterium in the salting process according to claim 7, is characterized in that during the salting of the step (5), the arranged vegetables are spiraled from the four sides to the center Arrange vertically, the leaves of the first layer of vegetables at the bottom face down, and the roots face up, and the roots of the second layer start to face down, and the leaves face up, and the arrangement is uniform in thickness; The four sides turn to the center and are steady. 9. the method for pickling vegetables suppressing nitrite and bacterium in the salting process according to claim 8 is characterized in that the bacteriostatic gas in the described step (6) is carbon dioxide, nitrogen, helium and argon One of. 10. the method for pickling vegetables suppressing nitrite and bacterium in the salting process according to claim 9 is characterized in that the installation of the inflation and exhaust switch of the present invention is to open a diameter of 2 on the EVOH film bag. -3mm hole, the filling and exhaust nozzle passes through the hole and is tightly sealed with a sealing gasket, and the gasket is coated with AB glue, and the latex tube is connected with the filling and exhaust nozzle, and the connection is reinforced with a fastening piece, and the latex tube is The other end is tightly sealed by a screw water stop valve.