Plant bacteriostatic agent, preparation method thereof and application of plant bacteriostatic agent in corrosion prevention of refined areca catechu

Abstract

The invention belongs to the field of natural pharmaceutical chemistry, and particularly relates to a plant bacteriostatic agent, a preparation method thereof and application of the plant bacteriostatic agent in corrosion prevention of refined areca nuts. The plant bacteriostatic agent is prepared from the following components in parts by weight: 60 to 80 parts of cortex cinnamomi extract, 2 to 5 parts of lemon extract, 2 to 5 parts of origanum vulgare extract and 5 to 20 parts of betel nut extract; the extraction method of the cinnamon extract comprises the following steps: adding deionized water and cellulase into cinnamon powder, carrying out mixed enzymolysis for 0.5-1.5 hours, putting a reaction system into an ultrasonic environment, heating, and keeping the system in a boiling state for 1-3 hours, so as to obtain a cinnamon extracting solution. The plant bacteriostatic agent disclosed by the invention can be used for effectively inhibiting moulds in the areca-nut raw material and also can be used for inhibiting various moulds in an air environment. The application of the plant bacteriostatic agent can provide a new scheme for areca nut storage and processing mildew prevention, and can provide practical basis and scientific data support for the plant bacteriostatic agent to effectively replace traditional preservatives potassium sorbate and sodium propanecarboxylate.

Description

Technical Field

[0001] The invention belongs to the field of natural drug chemistry, and specifically relates to a plant antibacterial agent, a preparation method thereof and application thereof in the preservation of refined betel nut. Background Art

[0003] In traditional technology, mechanical low-temperature storage and chemical agents are often used to inhibit bacteria in the storage and processing of betel nut. However, low-temperature storage has high costs and high energy consumption. Betel nut is easily affected by moisture, heat and mildew during the storage process and becomes moldy and deteriorates. The use of chemical fungicides will cause certain harm to the human body and the environment. In addition, the resistance of pathogens to chemical fungicides is constantly increasing, and the anti-mildew effect is greatly reduced.

[0004] Prior art CN201811407798.6 discloses an antibacterial agent and its preparation method and application. The present invention provides an antibacterial agent, which is an oxidized resveratrol solution, and the mass concentration of the oxidized resveratrol is 0.01%-0.1%. The antibacterial agent provided by the present invention only uses oxidized resveratrol, changes the mode of traditional composite antibacterial agents, reduces the addition of other auxiliary or functional ingredients, and studies common pathogens of fruit and vegetable rot, but single-component antibacterial agents are prone to drug resistance.

[0005] Some existing technologies use a combination of aromatic substances to inhibit bacteria, but most aromatic substances need to be stored at low temperatures, are highly irritating to the skin and eyes, have poor water solubility, and are easily oxidized and yellowed in the air, and thus are difficult to apply industrially on a large scale. Summary of the invention

[0006] The purpose of the present invention is to provide a plant antibacterial agent and a preparation method thereof and application thereof in the preservation of refined betel nut.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A plant antibacterial agent, comprising, by weight, 60-80 parts of cinnamon extract, 2-5 parts of lemon extract, 2-5 parts of oregano extract and 5-20 parts of betel nut extract;

[0009] The extraction method of the cinnamon extract comprises the following steps: adding deionized water and cellulase to cinnamon powder, mixing and enzymolyzing for 0.5-1.5 hours, placing the reaction system in an ultrasonic environment, heating, and keeping the system in a boiling state for 1-3 hours to obtain a cinnamon extract;

[0010] The method for extracting the betel nut extract comprises the following steps: crushing betel nut kernels to obtain betel nut kernel powder, adding deionized water to the betel nut kernel powder, heating the system to keep it in a boiling state for 2-4 hours, and obtaining a betel nut extract.

[0011] In one preferred embodiment, the solid-liquid ratio of the cinnamon powder to deionized water is 1:15-25 g / ml.

[0012] In a preferred embodiment, the amount of cellulase added is 1.5-2.5% of the mass of the enzymatic hydrolysis system.

[0013] In one preferred embodiment, the pH of the mixed enzymatic hydrolysis is 3-5 and the temperature is 35-45°C.

[0014] In a preferred embodiment, the particle size of the cinnamon powder is 40-100 mesh.

[0015] In one preferred embodiment, the frequency of ultrasound is 100-280w; and the ultrasound time is 1-3h.

[0016] The extraction rate of the active ingredients in cinnamon extract increased with the increase of ultrasonic power and the extension of ultrasonic time. However, when the power exceeded 300w and the time was greater than 3h, the yield decreased. This may be because the ultrasonic power was too high and the time was too long, which would make the extract cells more broken and more particulate impurities were separated, resulting in a decrease in the extraction rate.

[0017] The invention adopts ultrasonic and enzymolysis-assisted steam distillation to extract cinnamon extract, and after the extract is mixed with lemon extract, oregano extract and betel nut extract, the four extracts have a synergistic inhibitory effect on Aspergillus rubrum, Penicillium marneffei and Aspergillus ochraceus in betel nut.

[0018] In one preferred embodiment, the method for extracting lemon extract comprises the following steps:

[0019] The lemon is cut into small pieces, freeze-dried, crushed, and sieved to obtain lemon powder; an ethanol solution is added to the lemon powder, heated, ultrasonically extracted, and then filtered to recover the filtrate; the filter residue is repeatedly extracted, filtered, all filtrates are combined, and concentrated to obtain a lemon extract.

[0020] In one preferred embodiment, the freeze-drying process is as follows: the cut lemon pieces are frozen in a -40°C refrigerator for 10-12 hours, taken out, and placed in a vacuum freeze dryer, the cold trap temperature is set to -50±5°C, the vacuum degree is 6.0±0.5Pa, and the drying is stopped when the moisture content of the lemon pieces is no more than 5±0.64%.

[0021] In one preferred embodiment, the particle size of the lemon powder is 40-60 mesh.

[0022] In a preferred embodiment, the ethanol solution is an ethanol aqueous solution with a mass concentration of 70-85wt%.

[0023] In one preferred embodiment, the solid-liquid ratio of lemon powder to ethanol solution is 1:15-25 g / ml.

[0024] In one preferred embodiment, the extraction temperature of the lemon extract is 50-70°C.

[0025] In one preferred embodiment, after the filter residue is repeatedly extracted and filtered for 2-5 times, the obtained filtrate is combined with the first filtrate. The process of extracting the filter residue is the same as the process conditions of extracting the lemon powder.

[0026] In one preferred embodiment, the concentration of the concentrated lemon extract is 1-2 g / mL.

[0027] In one preferred embodiment, the method for extracting lemon extract comprises the following steps:

[0028] The surface of the lemon was cleaned with ultrapure water, and after the surface was dried, the lemon was cut into small pieces for freeze-drying; after drying, the lemon pieces were taken out and crushed with a grinder; the lemon powder was passed through a 40-mesh sieve to ensure that the fine powder was uniform in size, and then the lemon powder was stored in a dry, ventilated and light-proof ground-mouth bottle for use; 10 g of lemon powder was added to 200 ml of 85% ethanol solution, with a solid-liquid ratio of 1:20; ultrasonic extraction was performed at 60°C for 25 min, vacuum filtration was performed, the filtrate was recovered, the filter residue was extracted under the same conditions for 3 times, all the filtrates were mixed, and rotary evaporated to 10 mL to obtain 1 g / mL lemon extract.

[0029] In one preferred embodiment, the method for extracting oregano extract comprises the following steps: adding deionized water to oregano powder, extracting for 7-9 hours at a material ratio of 1:5-9, and taking the upper layer of oily liquid to obtain the oregano extract.

[0030] In one preferred embodiment, the mesh size of the betel nut kernel powder is 40-60 mesh.

[0031] In one preferred embodiment, the solid-liquid ratio of betel nut kernel powder and deionized water is 1:5-15 g / ml.

[0032] The present invention also claims a method for preparing the plant bacteriostatic agent, comprising: mixing cinnamon extract, lemon extract, oregano extract and betel nut extract to obtain the plant bacteriostatic agent.

[0033] The present invention also claims to protect the application of the plant bacteriostatic agent, and the application of the plant bacteriostatic agent includes the application of the plant bacteriostatic agent in inhibiting and / or killing areca nut mold.

[0034] In a preferred embodiment, the mold includes one or more of Aspergillus rubrum, Penicillium marneffei or Aspergillus ochraceus.

[0035] In one preferred embodiment, the added amount of the plant antibacterial agent is ≥2 ml / kg betel nut mass, and more preferably 2-3 ml / kg betel nut mass.

[0036] Compared with the prior art, the advantages of the present invention are:

[0037] 1. The present invention compares the effects of the plant antibacterial agent with those of commonly used traditional preservatives, and screens out 2-3 ml / kg of betel nut mass of the plant antibacterial agent, which has a better antibacterial and bactericidal effect on betel nut seeds.

[0038] 2. The plant antibacterial agent with a mass of 2-3 ml / kg betel nut has a good antibacterial and bactericidal effect on Aspergillus ochraceus, Aspergillus ochraceus, Penicillium in betel nut and various molds in the air. After 21 days of inoculation and culture, no bacterial growth was observed.

[0039] It can be concluded that the plant antibacterial agent used can effectively inhibit the molds in the betel nut raw materials (such as red Aspergillus, Penicillium and Aspergillus ochraceus), and can also inhibit various molds in the air environment. The application of this plant antibacterial agent can provide a new solution for the storage and processing of betel nut mold prevention. The test results of this project can provide practical basis and scientific data support for the plant antibacterial agent to effectively replace the traditional preservatives potassium sorbate and sodium propyl formate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0041] Figure 1 Because Penicillium, Aspergillus ochraceus, etc. grow well in Sabouraud's medium, but Aspergillus rubrum does not grow;

[0042] Figure 2 No type of mold can grow in Sabouraud medium added with 0.2% mass concentration of plant antibacterial agent. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0044] Example 1

[0045] The formula for adding plant antibacterial agent is:

[0046] Table 1 Plant antibacterial agent formula

[0047]

[0048] The components of each of the above examples are calculated by weight.

[0049] The preparation method of the plant antibacterial agent is as follows:

[0050] (1) Extraction method of cinnamon extract 1:

[0051] The cinnamon extract is extracted by ultrasonic and bio-enzyme-assisted steam distillation, and the cinnamon is naturally dried and crushed into 40-mesh cinnamon powder for preparing the cinnamon extract. 10 g of cinnamon powder is added to a 500 ml distillation kettle, and cellulase (purchased from Hunan Lierkang Biological Co., Ltd.) is added, the cellulase addition amount is 2%, the solid-liquid ratio is 1:20, the enzymolysis temperature is 40°C, the pH is 4, and the enzymolysis time is 1 hour; then ultrasonication is performed at a frequency of 100-280w, the ultrasonication time is 1 hour, and then the system is heated to keep the system in a boiling state for 1.8 hours to obtain a cinnamon extract.

[0052] (2) Extraction method of cinnamon extract 2:

[0053] The cinnamon extract was extracted by steam distillation. After the cinnamon was naturally dried, it was crushed into 40 mesh cinnamon powder for preparing the cinnamon extract. 10g of cinnamon powder was taken and placed in a 500ml distillation kettle with a material-liquid ratio of 1:20. The system was heated to keep boiling for 1.8h to obtain the cinnamon extract.

[0054] (3) Extraction method of lemon extract:

[0055] Use ultrapure water to clean the surface of the lemon, and cut the lemon into small pieces for freeze-drying after the surface is dry. The freeze-drying process is as follows: freeze the cut lemon pieces in a -40℃ refrigerator for 11 hours, take them out, put them into a vacuum freeze dryer, set the cold trap temperature to -50±5℃, and the vacuum degree to 6.0±0.5Pa. Test the moisture content of the lemon pieces every two hours, and stop drying when the dry basis moisture content of the lemon pieces is not more than 5±0.64%. After drying, take out the lemon pieces and crush them using a crusher. Pass the lemon powder through a 40-mesh sieve to ensure that the fine powder is uniform in size. Finally, store the lemon powder in a dry, ventilated, and light-proof ground-mouth bottle for use. Take 10g of lemon powder and add it to 200ml of 85% ethanol solution with a material-liquid ratio of 1:20. Use 60℃ ultrasonic extraction for 25min, vacuum filter, and recover the filtrate. Extract the residue under the same conditions three times, mix all the filtrates, and rotary evaporate to 10mL to obtain 1g / mL lemon extract.

[0056] (4) Extraction method of oregano extract:

[0057] The oregano extract was extracted by steam distillation. The material ratio was 1:7 and the extraction was carried out for 8 hours. The upper oily liquid was taken and transferred to a brown sample bottle, which was sealed and stored in a refrigerator at 4°C for later use.

[0058] (5) Areca nut extract

[0059] After hot air drying, the betel nut kernels were crushed into 40 mesh betel nut kernel powder for preparing betel nut kernel extract. 10 g of betel nut kernel powder was placed in a 500 ml distillation kettle with a material-liquid ratio of 1:10, and then heated to keep the system in a boiling state for 3 hours to obtain betel nut extract.

[0060] The cinnamon extract, lemon extract, oregano extract and betel nut extract are mixed according to the formula ratio to obtain the plant antibacterial agents of formula 1 to formula 3.

[0061] Example 2

[0062] 1. Betel nut counter-inoculation experimental method:

[0063] Betel nut inoculation: After betel nuts are bagged, spray mixed bacterial spore liquid for 10 3 (Mixed bacteria: Aspergillus erythrorhizium, Penicillium marneffei, Aspergillus ochraceus), after the bacterial solution and betel nut are evenly mixed, heat seal the package, place it in an incubator at 30℃, and test it once a week to check the number of bacteria (only the number of bacteria is read on the total colony count plate) and the number of molds.

[0064] 2. Antibacterial experimental method:

[0065] Prepare plant extract solutions of different gradients: dilute the natural extract with pure water to different concentrations (1 ml / kg, 2 ml / kg, 3 ml / kg) and place 10 ml in a sterilized test tube.

[0066] Then, the mixture was mixed according to the proportion in Example 1 to obtain a plant antibacterial agent.

[0067] The mixed bacteria are Aspergillus rubrum, Penicillium marneffei and Aspergillus ochraceus, and the spore liquid is prepared for 10 3 CFU / g, directly drop 0.1ml into the above-mentioned natural extracts of different gradients, seal the test tubes with stoppers, and place them in an incubator at 25-28 degrees. Observe the bacterial growth every 2 days and record the results.

[0068] 3. Minimum inhibitory concentration (MIC) test method

[0069] (1) Experimental purpose: To test samples of different concentrations and determine the minimum inhibitory concentration for different microorganisms in the liquid culture system.

[0070] (2) Experimental materials

[0071] Nutrient broth culture medium, hypertonic culture medium, 0.5% sterile TTC colorimetric agent, sterile distilled water, test samples, experimental strains, sterile test tubes, etc.

[0072] (3) Experimental strains

[0073] Standard strains: Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger;

[0074] Strains isolated from corrupt samples: Aspergillus flavus, Penicillium, Aspergillus niger, Aspergillus ochraceus, and Aspergillus rubrum.

[0075] (4) Experimental methods

[0076] A. Preparation of bacterial suspension:

[0077] Bacteria and yeast: obtain a single colony of the strain by streaking, take a single colony with a bacterial loop, inoculate it into nutrient broth, and culture it overnight for about 20 hours; before the experiment, adjust different dilution concentrations to make the final bacterial solution concentration around 7-8lg cfu / ml. This step can be verified by a preliminary experiment before the formal experiment to confirm the concentration of the bacterial solution after culture and select the appropriate dilution multiple.

[0078] Fungus: Inoculate the fungus strain onto the culture medium plate by the streak method and culture until a large number of spores are produced on the surface of the colony. Scrape a small amount of spores with an inoculation loop into sterile saline and count them under a microscope.

[0079] B. Sample diluent preparation: Prepare sterile distilled water, you can use a 500ml thread bottle, and adjust the pH to 6 before sterilization; if you need to test the sample effect under different pH values, you can adjust the distilled water to the required pH in this step. After sterilization and before the experiment, add 2% TTC colorimetric agent.

[0080] C. Sample solution preparation: Weigh the sample and dilute it with sterile distilled water containing TTC colorimetric reagent prepared in the previous step. Determine the preparation concentration of different sample solutions based on the recommended concentration of the sample. The negative control can be adjusted according to the actual experimental situation.

[0081] D. Preparation of double nutrient broth: use twice the amount of culture medium indicated on the label to prepare nutrient broth containing double nutrients, and add other nutrients according to the growth requirements of the strain. Use double broth to dilute the bacterial suspension so that the final inoculation concentration of bacteria and yeast is about 5-6lg cfu / ml, and the final inoculation concentration of mold is about 4-5lg cfu / ml.

[0082] E. Sampling and inoculation: Prepare sterilized test tubes, each containing 4.5 ml of the test solution (i.e., sample solution + double broth mixture) and 0.5 ml of bacterial solution. Use the two-fold dilution method to complete the dilution gradient of each group. After the inoculation is completed, place the test tubes at the optimal temperature for incubation. Bacteria are cultured for 24-48 hours, and yeast and mold are cultured for 72 hours. Observe the color change of the test tubes. The lowest concentration that does not change color is the minimum inhibitory concentration (MIC) of the sample for the test bacteria. Finally, the experimental results are counted.

[0083] 4. Test items

[0084] 2. Antibacterial effect

[0085] Table 2 Minimum inhibitory concentration of plant antibacterial agents

[0086]

[0087]

[0088] / That is, the minimum inhibitory concentration was not tested within the concentration of 20μl / ml.

[0089] 3. Betel nut anti-inoculation experiment

[0090] Table 3 Anti-inoculation experiment of plant antibacterial agents in green fruits

[0091]

[0092] Table 4 Counter-inoculation experiment of plant antibacterial agents in tobacco fruit

[0093]

[0094] From Table 3 and Table 4, we can see that:

[0095] There were certain differences in the measured D0 mold values ​​in each group, with an average value of 10065 CFU / g, which was close to the planned inoculation amount of 10000 CFU / g, indicating that the inoculation was successful.

[0096] For green betel nut, the total number of molds detected on the second day showed that: the total number of molds in formula 1 < the total number of molds in formula 2 < the total number of molds in comparison formula 1 < the total number of molds in formula 3 < comparison formula 4 < comparison formula 3 < comparison formula 2 < comparison formula 5. Judging from the changes in the sterilization rate, formulas 1-3 showed stronger mold killing ability than other groups, so formulas 1-3 had a better antibacterial effect in green fruit.

[0097] For the tobacco fruit betel nut, the total number of molds detected on the second day showed that: the total number of molds in formula 1 < the total number of molds in formula 3 < the total number of molds in formula 2 < the total number of molds in comparison formula 1 < the total number of molds in comparison formula 3 < the total number of molds in comparison formula 4 < the comparison formula 5 < the comparison formula 2. From the change of the sterilization rate, formulas 1-3 showed stronger mold killing ability than other groups, so formulas 1-3 had better antibacterial effects in tobacco fruit. It can be seen that among the plant antibacterial agents used, cinnamon, lemon, oregano, and betel nut kernel extracts played a significant synergistic role, which can effectively inhibit the molds and bacteria in the betel nut raw materials.

[0098] It can be seen that formula 1-3 showed good antibacterial effects in both green fruit and tobacco fruit.

[0099] Table 5 The total number of mold results of betel nut reverse inoculation experiment

[0100]

[0101] The total number of molds recorded at different times after inoculation in betel nut is shown in the table above:

[0102] There were certain differences in the measured D0 mold values ​​of each group, with an average value of 9800 CFU / g, which was close to the planned inoculation amount of 10000 CFU / g, indicating that the inoculation was successful.

[0103] For green betel nut, the total number of molds detected on the second day showed that the total number of molds in the experimental group (2 ml / kg of plant antibacterial agent added) was less than the total number of molds in the control group (2 g / kg of potassium sorbate added) and less than the total number of molds in the blank group. From the change of the bactericidal rate, the experimental group (2 ml / kg of plant antibacterial agent added) showed a stronger ability to kill molds than the control group (2 g / kg of potassium sorbate added). Therefore, adding plant preservatives has a better antibacterial effect than adding potassium sorbate. From the test data on the 5th day, it can be seen that the total number of molds added with preservatives was less than 10 CFU / g, while the total number of molds in the blank group was 1000 CFU / g. Therefore, adding two preservatives can effectively inhibit the growth of molds in betel nut. For the blank group, the mold was inoculated in the betel nut system. From 0 to 5 days, the total number of molds showed a downward trend; from 5 to 11 days, the total number of molds showed an upward trend; it may be because betel nut itself has less nutrients, and it takes a certain time to grow in betel nut, but molds may multiply in large numbers under suitable conditions.

[0104] For tobacco betel nut, the total number of molds detected on the second day showed that the total number of molds in the experimental group (2 ml / kg of plant antibacterial agent added) was less than the total number of molds in the control group (2 g / kg of potassium sorbate added) and less than the total number of molds in the blank group. From the change in the bactericidal rate, the experimental group (2 ml / kg of plant antibacterial agent added) showed a stronger ability to kill molds than the control group (2 g / kg of potassium sorbate added), so adding plant preservatives has a better antibacterial effect than adding potassium sorbate. The test data on the 5th day showed that the total number of molds in the preservatives was less than 10 CFU / g, while the mold content in the blank group was 1200 CFU / g, so adding two preservatives can effectively inhibit the growth of molds in tobacco betel nut.

[0105] Example 3

[0106] Screening of concentration of plant antibacterial agents

[0107] With reference to the national standard 2760, the following three preservatives, potassium sorbate (2.0g / kg), sodium benzoate (2.0g / kg) and different concentrations of plant antibacterial agents were selected to treat the original seeds of green fruit and tobacco fruit, respectively. Betel nut and sterile water were mixed in a ratio of 1:2, and the corresponding amount of preservatives was added according to the concentration marked above. They were soaked at 40°C for 4 hours, and the roasted seeds were simulated for drying. Then, the roasted seeds were counted before and after the treatment with Bengal red medium. At the same time, the plant antibacterial agent of formula 1 was sprayed on the raw seeds at a mass ratio of 1ml / kg, 2ml / kg, and 3ml / kg for 4 hours, and then the roasted seeds were simulated for drying, and then the roasted seeds were counted before and after the treatment with Bengal red medium. The results are shown in Table 6.

[0108] Table 6 Preservative screening test

[0109] Processing / Sample Green fruit seeds (CFU / g) Tobacco fruit seeds (CFU / g) No treatment <![CDATA[6.3×10 5 ]]> <![CDATA[1.07×10 4 <!-- 7 -->]]> Potassium sorbate (2.0g / kg) ＜10 ＜10 Sodium benzoate (2.0g / kg) ＜10 ＜10 Plant antibacterial agent 1ml / kg <![CDATA[2.1×10 2 ]]> <![CDATA[1.4×10 2 ]]> Plant antibacterial agent 2ml / kg ＜10 ＜10 Plant antibacterial agent 3ml / kg ＜10 ＜10

[0110] As shown in Table 6, the dosage of 2ml / kg and 3ml / kg of the plant antibacterial agent can achieve the bactericidal and antibacterial effects of traditional preservatives. The 1ml / kg plant antibacterial agent has a certain antibacterial and antibacterial effect, but the antibacterial and antibacterial effect is not thorough.

[0111] Example 4

[0112] Inhibitory effect of plant antibacterial agents on the main fungi in betel nut

[0113] The antibacterial effect of 2 ml / kg of the plant antibacterial agent on the screened strains of Aspergillus rubrum, Aspergillus ochraceus and Penicillium was tested on MY medium and Sabouraud medium, a common medium for molds and yeasts. The MY medium includes: 40 parts of sucrose, 2 parts of malt extract, 0.5 parts of yeast extract, 0.2 parts of dipotassium hydrogen phosphate, 2 parts of agar, and 100 parts of water. The test method is shown in Table 8, and the observation results after 21 days are shown in Table 7.

[0114] Table 7 Experimental design of the bactericidal effect of plant antibacterial agents on major molds

[0115]

[0116]

[0117] The sterilized culture medium such as plant antibacterial agent was cooled to about 50°C before being added, and aseptic operation was strictly performed. At the same time, the culture dish sealing film was used to prevent the evaporation of water in the culture medium and to prevent contamination during the culture process. Three parallels were made for all groups. After inoculation, they were placed in a 28°C constant temperature incubator for 21 days, and the test results were observed and recorded every day as shown in Table 8.

[0118] Table 8 Observation results of the bactericidal effect of plant antibacterial agents on major molds

[0119]

[0120] In summary, the present invention compares the effects of commonly used traditional preservatives, and screens out that the plant bacteriostatic agent with a concentration of 2ml / kg and 3ml / kg has a good antibacterial and bactericidal effect on betel nut seeds. At the same time, the plant bacteriostatic agent with a concentration of 2ml / kg has a good antibacterial and bactericidal effect on Aspergillus ochraceus, Penicillium in betel nut and various molds in the air. After inoculation and culture for 21 days, no bacteria grew.

[0121] It can be concluded that the plant antibacterial agent used (organic acids, aldehydes and aromatic essential oils in cinnamon, lemon, oregano and betel nut kernel extracts) can effectively inhibit the molds in the royal betel nut raw materials (such as red aspergillus, penicillium and ochraceous aspergillus), and can also inhibit various molds in the air environment. The application of this plant antibacterial agent can provide a new solution for the storage and processing of betel nut mold prevention. The test results of this project can provide practical basis and scientific data support for the plant antibacterial agent to effectively replace the traditional preservatives potassium sorbate and sodium propyl formate.

[0122] The above is a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes according to the technical solutions and concepts of the present invention, which should be covered by the protection scope of the claims of the present invention.

Claims

1. A plant antibacterial agent, characterized in that: In parts by weight, the composition comprises 60-80 parts of cinnamon extract, 2-5 parts of lemon extract, 2-5 parts of oregano extract and 5-20 parts of betel nut extract; The extraction method of the cinnamon extract comprises the following steps: adding deionized water and cellulase to cinnamon powder, mixing and enzymolyzing for 0.5-1.5 hours, placing the reaction system in an ultrasonic environment, heating, and keeping the system in a boiling state for 1-3 hours to obtain a cinnamon extract; The method for extracting the betel nut extract comprises the following steps: crushing betel nut kernels to obtain betel nut kernel powder, adding deionized water to the betel nut kernel powder, heating the system to keep it in a boiling state for 2-4 hours, and obtaining a betel nut extract.

2. The plant antibacterial agent according to claim 1, characterized in that The solid-liquid ratio of the cinnamon powder to deionized water is 1:15-25 g / ml; the added amount of the cellulase is 1.5-2.5% of the mass of the enzymatic hydrolysis system; the pH of the mixed enzymatic hydrolysis is 3-5, and the temperature is 35-45°C.

3. The plant antibacterial agent according to claim 1, characterized in that The frequency of ultrasound is 100-280w; the time of ultrasound is 1-3h.

4. The plant antibacterial agent according to claim 1, characterized in that The method for extracting lemon extract comprises the following steps: cutting lemon into small pieces, freeze-drying, crushing and sieving to obtain lemon powder; adding ethanol solution to the lemon powder, heating, ultrasonic extraction, filtering and recovering filtrate; repeatedly extracting the filter residue, filtering, combining all filtrates and concentrating to obtain lemon extract.

5. The plant antibacterial agent according to claim 4, characterized in that The ethanol solution is an ethanol aqueous solution with a mass concentration of 70-85wt%; the solid-liquid ratio of lemon powder to ethanol solution is 1:15-25 g / ml.

6. The plant antibacterial agent according to claim 4, characterized in that The extraction temperature of the lemon extract is 50-70° C. After the filter residue is repeatedly extracted and filtered for 2-5 times, the obtained filtrate is combined with the first filtrate.

7. The plant antibacterial agent according to claim 1, characterized in that The extraction method of oregano extract comprises the following steps: adding deionized water to oregano powder, extracting for 7-9 hours at a material ratio of 1:5-9, and taking the upper oily liquid to obtain the oregano extract.

8. The plant antibacterial agent according to claim 1, characterized in that The mesh number of the betel nut kernel powder is 40-60 meshes; the solid-liquid ratio of the betel nut kernel powder to deionized water is 1:5-15 g / ml.

9. The method for preparing the plant bacteriostatic agent according to any one of claims 1 to 8, characterized in that: include: The plant antibacterial agent is obtained by mixing cinnamon extract, lemon extract, oregano extract and betel nut extract.

10. Use of the plant bacteriostatic agent according to any one of claims 1 to 8, comprising use of the plant bacteriostatic agent in inhibiting and / or killing areca nut mold.

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