Fermentation inoculant and application thereof to simultaneous reduction of nitrite and biogenic amine in fermented vegetables

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a fermentation inoculant and application thereof to simultaneous reduction of nitrite and biogenic amine in fermented vegetables. A leavening agent used in the method is lactobacillus plantarum MQ4, and the lactobacillus plantarum MQ4 is combined with oligosaccharide and glucose to be subjected to heat preservation and activation to obtain a liquid strain; mixing a carbon source with saline water to obtain a pickling liquid, then immersing the vegetables into the pickling liquid, and inoculating a liquid strain to obtain a fermentation system; after the fermentation system is subjected to standing balance, sealed fermentation is performed to obtain the fermented vegetables, and the nitrite and the biogenic amine of the fermented vegetables can be reduced at the same time. According to the invention, the oligosaccharide is supplemented to regulate the metabolism of lactic acid bacteria in the vegetable fermentation process, and based on the synergistic effect of the lactobacillus plantarum and the oligosaccharide, not only can the quality of the fermented vegetables be effectively improved, but also the contents of nitrite and biogenic amine are effectively controlled, and the edible safety of the fermented vegetables is fully improved; and the method is simple, convenient, environment-friendly, easy for industrial production and wide in market application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and specifically discloses a fermentation bacterial agent and an application thereof for simultaneously reducing nitrite and biogenic amines in fermented vegetables. Background Art

[0002] As people's health awareness continues to improve, the requirements for food safety and health are getting higher and higher. Nitrite may reach a high concentration in fermented vegetables, and after entering the human body, nitrite may be converted into carcinogens such as nitrosamines. Long-term intake is harmful to human health. Moreover, biogenic amines are nitrogen-containing organic compounds produced by microbial metabolism during the production of fermented vegetables. Excessive intake of biogenic amines may cause adverse reactions such as allergies and increased blood pressure in the human body.

[0003] Traditional fermented vegetables are mostly produced in a natural fermentation mode. The fermentation process is uncontrollable, the product quality is unstable, and it is easy to be contaminated by bacteria, resulting in the production of harmful substances such as nitrite and biogenic amines. For example, in the production of traditional kimchi, in order to prevent the vegetables from rotting during the pickling process, high concentrations of salt are often added, which not only affects the taste of the product, but also causes the loss of nutrients during the desalting process.

[0004] Therefore, finding methods to inhibit the residual nitrite and biogenic amines in fermented vegetables is of great practical significance for improving the food safety of fermented vegetable products and the high-quality development of the pre-prepared food industry. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a fermentation agent and its use for simultaneously reducing nitrite and biogenic amines in fermented vegetables. By regulating the metabolism of specifically screened microorganisms, the growth of harmful microorganisms is inhibited, the production of nitrite and biogenic amines is reduced, and the growth of beneficial lactic acid bacteria is promoted, thereby improving the flavor and nutritional value of fermented vegetables, thereby achieving unexpected technical effects.

[0006] In one aspect of the present invention, a fermentation agent is first provided, wherein the fermentation agent is Lactiplantti bacillus pentosus MQ4, collected from Wuhu, Anhui Province, and deposited in the China Center for Type Culture Collection on May 30, 2023. The storage address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the storage number is CCTCC NO: M 2023874.

[0007] In another aspect of the present invention, there is provided a use of the Lactobacillus plantarum MQ4 (CCTCC NO: M2023874) in vegetable fermentation to reduce nitrite and biogenic amines in the fermented vegetables.

[0008] In one embodiment of the present invention, the use comprises mixing vegetables, a fermentation agent and a pickling liquid, stirring them evenly, and fermenting them to obtain fermented vegetables.

[0009] The main scheme is: first, mix oligosaccharides with edible salt, water, calcium lactate, and white sugar to prepare fermented vegetable pickling liquid, and mix the activated Lactobacillus plantarum liquid with the pickling liquid to prepare vegetable yeast liquid; then, according to the material-liquid ratio, immerse the fresh vegetables in the yeast liquid, let it stand in a closed fermentation, and obtain the fermented vegetables after the fermentation ends.

[0010] The specific scheme operation of the present invention includes the following steps:

[0011] (1) Preparation of pickling liquid: The pickling liquid comprises the following components by weight: 30-70 parts of water, 1-3 parts of edible salt, 0.2-2.0 parts of oligosaccharides, 0.1-0.3 parts of white sugar, and 0.05-0.4 parts of calcium lactate;

[0012] (2) Preparation of liquid strains:

[0013] S1, inoculating plant lactobacillus MQ4 into MRS medium for cultivation to obtain culture solution; then inoculating the culture solution into new MRS medium for expanded cultivation, collecting the bacterial solution after cultivation for freeze drying to obtain freeze-dried strains of plant lactobacillus;

[0014] S2. Add 0.01-0.1 parts of oligosaccharides and 0.06-0.09 parts of glucose to 2-4 parts of water, boil and cool, then add 0.03-0.07 parts of freeze-dried Lactobacillus plantarum, and activate by heat preservation to obtain liquid strains;

[0015] (3) Soaking vegetables: Mix fresh vegetables with the pickling solution of step (1), then add the liquid bacteria of step (2), stir evenly (so that the bacteria cells are fully in contact with the vegetables), and obtain a fermentation system;

[0016] (4) Fermentation of vegetables: After the fermentation system is allowed to stand for a period of time, it is sealed and fermented. After the fermentation is completed, fermented vegetables are obtained, thereby achieving the goal of simultaneously reducing the nitrite and biogenic amines in the fermented vegetables.

[0017] (5) Packaging and storage: After fermentation, the fermented vegetables are packaged, sterilized and stored (the storage temperature is between 20 and 25°C).

[0018] Furthermore, the oligosaccharides in steps (1) and (2) are oligosaccharides extracted and biosynthesized from non-soybean plants, and the oligosaccharides include oligofructose, stachyose or mannose derived from banana, wheat, potato, burdock, Jerusalem artichoke, onion, banana, garlic and leek.

[0019] Furthermore, in step (2) S1, the culture conditions are: temperature of 37° C., time of 24 hours; and inoculation amount of 1-2%.

[0020] Furthermore, in S2 of step (2), the boiling time is 5-10 minutes and the cooling temperature is 30-35°C.

[0021] Furthermore, in step (2) S2, the temperature of the heat preservation activation is 30 to 35° C., and the time is 10 to 12 hours.

[0022] Furthermore, in step (3), the mass ratio of vegetables to pickling liquid is 1:1 to 2:1; the amount of liquid bacteria added is 15 to 25 mL per 100 g of vegetables; and the stirring time is 30 to 60 seconds.

[0023] Furthermore, in step (4), the static equilibrium period is 10-15 minutes, the fermentation temperature is 20-25° C., and the fermentation time is 4-7 days.

[0024] Furthermore, the vegetables include any one or more of root vegetables, stem vegetables, leafy vegetables, legumes, solanaceae, and gourds.

[0025] Finally, the present invention also provides a fermentation agent product, characterized in that the fermentation agent product comprises the fermentation agent Lactobacillus plantarum MQ4 (CCTCC NO: M 2023874) mentioned above.

[0026] The beneficial effects of this application are:

[0027] 1. The present invention uses plant lactobacillus MQ4 (CCTCC NO: M 2023874) screened by itself as a fermentation agent for vegetable fermentation; oligosaccharide is a novel functional sugar source, which integrates nutrition, health care and diet therapy and is widely used in the fields of food, health products, beverages, medicine, feed additives, etc.; however, there is no related research on combining plant lactobacillus with oligosaccharide to control nitrite and biogenic amine in the field of vegetable fermentation, and the present invention has originality.

[0028] 2. The present invention utilizes Lactobacillus plantarum MQ4 (CCTCC NO: M 2023874) alone as a fermentation agent, and can enrich the flavor and functional substances of fermented vegetables without adding other commercial fermentation agents, thereby solving the defects of insufficient flavor of fermented vegetables and the like; at the same time, it overcomes the problem of slow conventional fermentation speed, greatly shortens the production time, and improves the production efficiency.

[0029] 3. The present invention uses the mode of adding functional oligosaccharides to regulate the metabolism of lactic acid bacteria in the vegetable fermentation process in the fermented vegetable production process, based on the synergistic effect of plant lactobacillus MQ4 and oligosaccharides, not only can the quality of fermented vegetables be effectively improved, but also the nitrite and biogenic amine contents are effectively controlled simultaneously, the accumulation phenomenon of the residual nitrite and biogenic amines of fermented vegetables is avoided, the edible safety of fermented vegetables is fully improved, and the quality stability of fermented vegetables is improved. Moreover, the production technology of the present invention is energy-saving and environmentally friendly, is easy to large-scale production, can be widely promoted, and has good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the content of nitrite and biogenic amines in fermented vegetables. Different letters represent significant differences (p<0.05). DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art of the present invention generally understand. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and / or materials related to the documents. In the event of conflict with any incorporated document, the content of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0034] In an embodiment of the present invention, a method for obtaining a freeze-dried strain of plant lactobacillus is as follows: plant lactobacillus MQ4 (CCTCCNO: M 2023874) is inoculated into an MRS culture medium at an inoculation amount of 1% (m / v, g / ml), and cultured at 37° C. for 24 hours to obtain a culture solution; then the culture solution is inoculated into a new MRS culture medium at an inoculation amount of 1% (v / v) for expanded culture, and after culturing at 37° C. for 24 hours, the bacterial solution is collected and freeze-dried (pre-frozen at -80° C. overnight, freeze-drying temperature is -60° C., vacuum degree is 105 Pa, and drying is performed for 24 hours) to obtain freeze-dried strains of plant lactobacillus;

[0035] The oligosaccharides used in the method of the present invention are oligosaccharides extracted and biosynthesized from non-soybean plants, including oligofructose, stachyose or mannose derived from banana, wheat, potato, burdock, Jerusalem artichoke, onion, banana, garlic and leek. Specifically, the oligosaccharide used in the embodiment of the present invention is stachyose.

[0036] The vegetables used in the method of the present invention include any one or more of root vegetables, stem vegetables, leafy vegetables, legumes, solanaceous fruits, and gourds; specifically, the vegetables used in the implementation case of the present invention are beans.

[0037] Embodiment 1:

[0038] (1) Preparation of pickling solution: The pickling solution comprises, by weight, 70 parts of water, 2 parts of edible salt, 1 part of stachyose, 0.2 parts of white sugar, and 0.4 parts of calcium lactate.

[0039] (2) Preparation of liquid bacterial strains: Add 0.1 parts of stachyose and 0.08 parts of glucose to 4 parts of water, boil and cool to 30° C., then add 0.06 parts of freeze-dried Lactobacillus plantarum bacterial strains, maintain activation at 30° C. for 12 hours, and obtain liquid bacterial strains;

[0040] (3) Vegetable soaking: Mix fresh vegetables (beans) with pickling liquid in a mass ratio of 1:1, then add liquid bacteria (15 mL per 100 g of vegetables), and stir for 20 seconds. Stir evenly so that the bacteria cells are fully in contact with the vegetables to obtain a fermentation system;

[0041] (4) Fermentation of vegetables: The fermentation system was allowed to stand for 10 minutes and then sealed and fermented at 25° C. for 5 days to obtain fermented vegetables.

[0042] (5) Packaging and storage: The fermented vegetables obtained after the fermentation is completed are packed in PE bags and stored at 25°C after pasteurization.

[0043] Embodiment 2:

[0044] (1) Preparation of pickling liquid: by weight, including 50 parts of water, 1 part of edible salt, 1.5 parts of stachyose, 0.2 parts of white sugar, and 0.25 parts of calcium lactate, boil and then cool to 35°C.

[0045] (2) Preparation of liquid bacterial strain: Add 0.06 parts of stachyose and 0.08 parts of glucose to 3 parts of water, boil and cool to 30° C., then add 0.07 parts of freeze-dried Lactobacillus plantarum bacterial strain and activate the bacterial strain for 12 hours to obtain liquid bacterial strain;

[0046] (3) Vegetable soaking: fresh vegetables (beans) were mixed with pickling liquid at a mass ratio of 1.5:1, and then the liquid bacteria were added (15 mL was added for every 100 g of vegetables). The mixture was stirred for 40 seconds, and the stirring was evenly performed so that the bacteria cells were fully in contact with the vegetables to obtain a fermentation system.

[0047] (4) Fermentation of vegetables: The fermentation system was allowed to stand for 10 minutes and then sealed and fermented at 20° C. for 7 days to obtain fermented vegetables.

[0048] (5) Packaging and storage: The fermented vegetables obtained after the fermentation is completed are packed in PE bags and stored at 20°C after pasteurization.

[0049] Embodiment 3:

[0050] (1) Preparation of pickling liquid: by weight, including 30 parts of water, 1 part of edible salt, 0.5 parts of stachyose, 0.2 parts of white sugar, and 0.25 parts of calcium lactate.

[0051] (2) Preparation of liquid bacterial strains: Add 0.08 parts of stachyose and 0.07 parts of glucose to 3 parts of water, boil and cool, then add 0.03 parts of freeze-dried Lactobacillus plantarum, keep warm and activate to obtain liquid bacterial strains;

[0052] (3) Vegetable soaking: Mix fresh vegetables (beans) with pickling liquid in a mass ratio of 2:1, then inoculate with liquid bacteria (15 mL per 100 g of vegetables), and stir evenly to allow bacterial cells to fully contact the vegetables;

[0053] (4) Fermentation of vegetables: After inoculation, the vegetables were stirred for 30 seconds to allow the vegetables and the bacterial solution to be evenly mixed. The fermentation system was allowed to stand for 10 minutes and then sealed and fermented at 25°C for 7 days to obtain fermented vegetables.

[0054] (5) Packaging and storage: The fermented vegetables obtained after the fermentation is completed are filled in PE bags and pasteurized and stored at 25°C.

[0055] Comparative Example 1 (conventional natural fermentation): Commercial lactic acid bacteria, specifically lactic acid bacteria fermentation powder, purchased from Beijing Chuanxiu Technology Co., Ltd. were used.

[0056] The operation is as follows: the operation is the same as that in Example 3, except that the freeze-dried strain of plant lactobacillus of the present invention is replaced by conventional commercial lactic acid bacteria fermentation powder, and stachyose is not added. The other steps are the same as those in Example 3.

[0057] Comparative Example 2:

[0058] The operation is the same as that of Example 3, except that soybean oligosaccharides are used to replace the stachyose of the present invention.

[0059] 1. Sensory qualities of fermented vegetables;

[0060] After the fermented vegetables obtained in Examples 1-3 were stored for 3 days, the quality was evaluated by sensory evaluation. The results are shown in Table 1.

[0061] Table 1 Quality characteristics of fermented vegetables

[0062]

[0063] It can be seen from the analysis of the following table that, compared with Comparative Examples 1 and 2, the sensory quality of the fermented vegetables produced by the method of the present invention is significantly improved, and the appearance color, aroma, taste and texture are significantly higher than those of the vegetables fermented by conventional starter agents; moreover, by selecting oligosaccharides, the present invention compares stachyose with soybean oligosaccharides, and finds that stachyose can further improve the quality of fermented vegetables, achieving unexpected technical effects and effectively improving the quality of fermented vegetables.

[0064] 2. Detection of nitrite and biogenic amine content in fermented vegetables;

[0065] Taking the fermented vegetables prepared in Example 3 as an example, combined with Comparative Examples 1-2, the contents of nitrite and biogenic amines in the fermented vegetables after storage for 3 days were compared. The results are as follows: Figure 1 As shown;

[0066] The results show that the fermented vegetables (Example 3) prepared by using both plant lactobacillus and stachyose of the present invention have significantly lower nitrite and biogenic amine contents than those of comparative examples 1 and 2. It is effectively verified that the plant lactobacillus and stachyose of the present invention can play a synergistic role, not only can effectively improve the quality of fermented vegetables, but also effectively control the nitrite and biogenic amine contents, achieve substantial technical effects, and have good market application prospects.

[0067] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A fermentation agent, characterized in that: The fermentation bacteria agent is Lactobacillus plantarum (Lactiplanttibacillus pentosus) MQ4, with a preservation number of CCTCC NO: M 2023874.

2. A leavening agent product, characterized in that: The invention comprises the fermentation bacteria agent as claimed in claim 1.

3. Use of the fermentation agent according to claim 1 or the fermentation agent product according to claim 2 in vegetable fermentation to reduce nitrite and biogenic amines in the fermented vegetables.

4. The use according to claim 3, characterized in that Here are the steps: (1) Preparation of pickling liquid: The pickling liquid comprises the following components by weight: 30-70 parts of water, 1-3 parts of edible salt, 0.2-2.0 parts of oligosaccharides, 0.1-0.3 parts of white sugar, and 0.05-0.4 parts of calcium lactate; (2) Preparation of liquid strains: S1, inoculating plant lactobacillus MQ4 into MRS medium for cultivation to obtain culture solution; then inoculating the culture solution into new MRS medium for expansion culture, collecting the bacterial solution after cultivation and freeze-drying to obtain freeze-dried strains of plant lactobacillus; S2. Add 0.01-0.1 parts of oligosaccharides and 0.06-0.09 parts of glucose to 2-4 parts of water, boil and cool, then add 0.03-0.07 parts of freeze-dried Lactobacillus plantarum, and activate by heat preservation to obtain liquid strains; (3) soaking vegetables: taking fresh vegetables and mixing them with the pickling liquid of step (1), then adding the liquid bacteria of step (2), stirring evenly, and obtaining a fermentation system; (4) Fermentation of vegetables: After the fermentation system is allowed to stand for a period of time, it is sealed and fermented. After the fermentation is completed, fermented vegetables are obtained, thereby achieving the simultaneous reduction of nitrite and biogenic amines in the fermented vegetables; (5) Packaging and storage: After fermentation, the fermented vegetables are packaged, sterilized and stored.

5. The use according to claim 4, characterized in that The oligosaccharides in steps (1) and (2) are oligosaccharides extracted and biosynthesized from non-soybean plants, and include oligofructose, stachyose or mannose derived from banana, wheat, potato, burdock, Jerusalem artichoke, onion, banana, garlic and leek.

6. The use according to claim 4, wherein in step (2) S1, the culture conditions are: temperature of 37°C, time of 24 hours, and inoculation amount of 1-2%.

7. The use according to claim 4, characterized in that In S2 of step (2), the boiling time is 5-10 minutes, the cooling temperature is 30-35° C.; the temperature of the heat preservation activation is 30-35° C., and the time is 10-12 hours.

8. The use according to claim 4, characterized in that In step (3), the mass ratio of vegetables to pickling liquid is 1:1 to 2:1; the amount of liquid culture added is 15 to 25 mL per 100 g of vegetables; and the stirring time is 30 to 60 seconds.

9. The use according to claim 4, characterized in that: In step (3), further, in step (4), the static equilibrium period is 10-15 minutes, the fermentation temperature is 20-25° C., and the fermentation time is 4-7 days.

10. The use according to claim 4, characterized in that Vegetables include any one or more of root vegetables, stem vegetables, leafy vegetables, legumes, nightshades, and gourds.

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