[0019] Example 1:
[0020] Preparation method of food-grade plant-derived compound bacteriostatic agent:
[0021] (1) Preparation of plant extracts containing cinnamaldehyde: 60kg of ground cinnamon bark powder was taken by steam distillation and put into a flask, 160L of water was added, a condenser was installed, and reflux was heated for 10 minutes. After cooling, pour it into a distillation flask for steam distillation, and collect 80-100L of distillate;
[0022] The distillate was transferred to a separatory funnel and extracted twice with 40L portions of ether. Discard the water layer, transfer the ether layer into a small test tube, add a small amount of anhydrous sodium sulfate to dry, 20 minutes later, pour out the extract, heat it in a fume hood with a water bath to steam off the ether to obtain a plant extract containing cinnamaldehyde;
[0023] (2) Preparation of plant extract containing eugenol: weigh 15kg of clove buds, add 90L of water and soak in a distilling flask, heat directly to steam distillation, and collect about 30L of distillate;
[0024] Place the obtained distillate in a separatory funnel, extract twice with ethyl acetate (20L each time), combine the upper ethyl acetate extracts (the upper ethyl acetate extract contains eugenol), and then remove ethyl acetate , That is, plant extracts containing eugenol.
[0025] (3) Preheat the stirring pot to 60°C, preheat for 5 minutes, adjust the speed to 15r/min, turn on the stirring pot, add the plant extract containing cinnamaldehyde, the plant extract containing eugenol and caryophyllene ( (Purchased from Shanghai Yiji Industrial Co., Ltd.) totaling 100kg, adjust the speed of the stirring pot to 100r/min, stir for 50 minutes, and pack after stirring to obtain a food-grade plant-derived compound bacteriostatic agent; the food-grade plant-derived compound The mass fraction of cinnamaldehyde in the compound antibacterial agent is 55%, the mass fraction of eugenol is 12%, and the mass fraction of caryophyllene is 12%.
[0026] The performance test of the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 was carried out. The specific test methods and test results are as follows:
[0027] (1) Sensory evaluation and comparison of rosemary oil, BHT (2,6-di-tert-butyl-4-methylphenol) and food-grade plant-derived compound bacteriostatic agent:
[0028] Refer to Table 1 for sensory evaluation description data.
[0029] Table 1
[0030]
[0031] Table 2 shows the sensory evaluation results of rosemary oil, BHT (2,6-di-tert-butyl-4-methylphenol) and food-grade plant-derived compound bacteriostatic agent.
[0032] Table 2
[0033]
[0034] It can be seen from Table 2 that the food-grade plant-derived composite bacteriostatic agent obtained in Example 1 has a faint aroma, a uniform and stable system, a low odor and a harmonious smell.
[0035] (2) Antioxidant performance test of rosemary oil, BHT (2,6-di-tert-butyl-4-methylphenol) and food-grade plant-derived compound bacteriostatic agent: After food-grade plant-derived compound bacteriostasis The DPPH free radical test of the agent shows that the food-grade plant-derived compound bacteriostatic agent of Example 1 has antioxidant effect in addition to the bacteriostatic function, and the antioxidant performance is better than rosemary oil and BHT.
[0036] (3) Experimental program of antibacterial efficacy
[0037] The tested strains were: Staphylococcus aureus, Escherichia coli, Candida albicans, Pseudomonas aeruginosa, Aspergillus niger.
[0038] The minimum inhibitory concentration MIC of the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 was determined by the liquid medium dilution method. The specific method is as follows:
[0039] (1) Preparation of medium: nutrient broth medium;
[0040] (2) Preparation of bacterial suspension: Take activated Staphylococcus aureus, activated Escherichia coli and activated Pseudomonas aeruginosa in sterile distilled water to prepare 1×10 8 cfu/mL bacterial suspension; take the activated Candida albicans and the activated Aspergillus niger into sterilized distilled water to make 1×10 7 cfu/mL bacterial suspension; respectively take 1 mL of the bacterial suspension of the above-mentioned bacteria and fungi and mix them in a sterilized test tube to obtain a mixed bacterial suspension;
[0041] (3) Preparation of test tube containing preservative composition: using the food-grade plant-derived compound bacteriostatic agent and nutrient broth culture medium obtained in Example 1 at concentrations of 0.025%, 0.05%, 0.10%, 0.20%, 0.40 % And 0.80% nutrient broth medium containing bacteriostatic agent;
[0042] (4) Detection of minimum inhibitory concentration: add 0.1ml of mixed bacterial suspension to 10mL nutrient broth medium containing bacteriostatic agent at different concentrations, and mix them evenly; set up three parallel test groups, in which the observation of bacteria is placed Cultivate for 24 hours at 37°C, and culture for 48 hours at 28°C for observation of fungi; after the completion of the culture, draw 1ml of nutrient broth medium containing bacteriostatic agents at different concentrations into the plate, pour the appropriate amount of medium, and place the bacteria at 37 Cultivate at ℃ for 24h, observe the fungus at 28℃ and cultivate for 48h; get the total number of colonies on the plate and take the average value.
[0043] The antibacterial efficacy result data (MIC) is shown in Table 3:
[0044] table 3
[0045]
[0046] Note: "-" means that there is no growth of bacteria, "+" means that there are very few bacteria, "++" means that there are a few bacteria, and "++" means that there are a lot of bacteria.
[0047] It can be seen from Table 3 that the minimum inhibitory concentration of the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 is 0.05%, when the addition amount of the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 is not less than At 0.05%, the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 can simultaneously treat 5 kinds of fungi including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Aspergillus niger. Play an inhibitory role.
[0048] (4) Antibacterial efficacy experimental program under different pH conditions: According to the conventional experimental method of (three) antibacterial efficacy experimental program under different pH conditions, test its antibacterial efficacy under different pH conditions. The results are shown in Table 4. Show:
[0049] Table 4
[0050]
[0051] Note: "-" means that there is no growth of bacteria, "+" means that there are very few bacteria, "++" means that there are a few bacteria, and "+++" means that there are a lot of bacteria.
[0052] It can be seen from Table 4 that the food-grade plant-derived composite bacteriostatic agent obtained in Example 1 has a good bacteriostatic effect in the acid-base range of pH 4-10.
[0053] (5) High temperature stability experiment
[0054] Under high temperature conditions, in accordance with the conventional experimental method of (3) Antibacterial efficacy experimental program, the antibacterial efficacy of the nutrient broth medium containing bacteriostatic agent at a concentration of 0.05% under different high temperature conditions was tested. The results are shown in Table 5. Show:
[0055] table 5
[0056]
[0057] Note: "-" means that there is no growth of bacteria, "+" means that there are very few bacteria, "++" means that there are a few bacteria, and "+++" means that there are a lot of bacteria.
[0058] Table 5 shows that the food-grade plant-derived compound bacteriostatic agent obtained in Example 1 has different stability to different temperature conditions. The experimental results show that the temperature is below 100°C. The food-grade plant-derived compound obtained in Example 1 The compound antibacterial agent can still maintain excellent antibacterial effect.
