Natural biological preservative, opacifying essence as well as preparation and bacteriostatic test methods of natural biological preservative and opacifying essence

Abstract

The invention particularly relates to a natural biological preservative, opacifying essence and a preparation method and an antibacterial test method of the opacifying essence. The natural biological preservative comprises organic acid, natamycin, nisin and polylysine hydrochloride. The opacifying essence containing the natural biological preservative is prepared from the following raw materials in percentage by mass: 0.1 to 0.5 percent of citric acid, 0.2 to 2 percent of lactic acid, 0.01 to 0.2 percent of natamycin-beta cyclodextrin powder preparation, 0.01 to 0.08 percent of nisin, 0.1 to 0.5 percent of polylysine hydrochloride-glycerol preparation, 0 to 12 percent of modified starch, 0 to 20 percent of Arabic gum, 1 to 8 percent of caprylic capric triglyceride, 3 to 10 percent of rosin glyceride and the balance of water. And the balance of deionized water. The natural biological preservative has good sterilization and bacteriostasis capabilities, and can effectively inhibit the growth of microorganisms when being applied to the opacifying essence. The bacteriostatic test method for the opacifying essence can effectively and quickly test the preservative inhibition effect of the opacifying essence.

Description

Technical Field

[0001] The invention relates to the technical field of food additives, and in particular to a natural biological preservative, an emulsified flavor, and a preparation method and an antibacterial testing method thereof. Background Art

[0002] Food preservatives are widely used in the food industry because they can effectively prevent food from spoiling caused by microorganisms, thereby extending the shelf life of food. Therefore, preservatives are one of the main additives in the food industry, and more than 40 (types) of food preservatives are included in GB2760 Food Additives. At present, chemical preservatives are more commonly used in the food industry in my country, such as benzoic acid and its sodium salt, sorbic acid and its potassium salt, nitrite, dehydroacetic acid and its sodium salt, parabens and their sodium salts. Although they have the advantages of low price, easy use, and good use effect, with the improvement of people's living and consumption levels, and the enhancement and improvement of food safety awareness, preservatives in food will inevitably develop in the direction of natural and green. This is an inevitable trend in the development of the food industry, that is, the development of natural preservatives will gradually replace the various chemical preservatives that are widely used now.

[0003] Opacifying flavor (also known as turbidity agent, clouding agent, emulsifier, turbidity enhancer) is a kind of flavor that can be used to increase the turbidity of juice and its beverages; maintain the stability and natural appearance of the emulsion of juice beverages; improve the taste of beverages, enhance the lubricity and thickness of beverages; maintain the flavor of juice and its beverages, and help release and retain aroma. It is usually made of a mixture of edible emulsifiers (gum arabic, sodium starch octenyl succinate, etc.), edible oils and fats (caprylic and capric glyceride, palm oil, salad oil or soybean oil, etc.), weighting agents (rosin glyceride or sucrose acetate isobutyrate), edible preservatives (sodium benzoate, potassium sorbate, sodium dehydroacetate, parabens, etc.) and other food additives. It is widely used in juice beverages, carbonated beverages, sports drinks, functional beverages and any beverages that need to produce turbidity.

[0004] Patents disclosed in CN100333669C "A clouding agent and its preparation method", CN106579334A "Emulsifier", CN107853534A "Emulsifier preparation method" and other patents involving opacifying flavors all use chemical preservatives or the patent implementation cases do not clearly indicate the defects of the antiseptic technology. In addition, since the opacifying flavors on the market currently contain more than 50% water, a large amount of starch or protein carbohydrates and other nutrients, if appropriate antiseptic measures are not taken during the shelf life of the product, it is very easy to cause the growth and rapid reproduction of microorganisms such as mold, Escherichia coli and bacteria, affecting food quality and safety.

[0005] Comparing patents and market conditions, it can be seen that the current market opacifying flavor products and public patents all need to add a certain amount of chemical preservatives (such as sodium benzoate or potassium sorbate, etc.) for the purpose of preservation and antibacterial. However, chemical preservatives such as sodium benzoate and potassium sorbate do not conform to the modern healthy development concepts such as "green and natural" and "clean food labels".

[0006] In addition, in view of the safety and other defects of chemical synthetic food preservatives, governments of various countries are rapidly revising food safety standards to improve food safety and national health, while also using "green barriers" to protect their own food industries and reduce the impact of foreign food on their own food industries. For example, Japan has long banned the use of highly toxic sodium benzoate, and foods containing sodium benzoate cannot enter the Japanese market.

[0007] From the perspective of currently known information and mastered technologies, GB2760 allows the addition of several natural biological preservatives to food, and their antibacterial ranges are relatively narrow. Some have an inhibitory effect on fungi but not on bacteria; some have an inhibitory effect on only a few microorganisms. A single biological preservative cannot achieve a broad-spectrum antibacterial effect.

[0008] Therefore, it is necessary to propose a new solution to solve the above problems, that is, to develop a new, safer, more convenient to use broad-spectrum natural biological preservative that can both kill bacteria and inhibit bacteria, and can effectively replace the commonly used chemical preservatives in the market (such as sodium benzoate, potassium sorbate, etc.), so that the emulsifier flavor can inhibit the growth of microorganisms for at least 12 months to ensure the quality and safety of food. Summary of the invention

[0009] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a natural biological preservative, an emulsified flavor and a method for preparing an emulsified flavor; the natural biological preservative has good bactericidal and antibacterial capabilities, can be used to replace the chemical preservatives commonly used in the market, and is used in emulsified flavors to effectively inhibit the growth of microorganisms and ensure food safety.

[0010] Another object of the present invention is to provide a method for testing the antibacterial properties of an emulsion flavor containing a natural biological preservative, which can effectively and quickly test the antiseptic inhibitory effect of the emulsion flavor and ultimately ensure the quality and safety of the product.

[0011] The purpose of the present invention is achieved through the following technical scheme: a natural biological preservative, characterized by comprising organic acid, natamycin, nisin and polylysine hydrochloride.

[0012] Furthermore, the natural biological preservative comprises the following raw materials in parts by weight: 0.3-2.5 parts of organic acid, 0.01-0.2 parts of natamycin-β-cyclodextrin powder preparation, 0.1-0.5 parts of polylysine hydrochloride-glycerol preparation, and 0.01-0.08 parts of nisin.

[0013] Furthermore, each portion of the organic acid includes 0.1-0.5 portions of citric acid and 0.2-2 portions of lactic acid by weight.

[0014] The present invention provides an emulsified flavor containing the above-mentioned natural biological preservative, comprising the following raw materials in percentage by mass:

[0015]

[0016] Furthermore, the emulsified flavor containing natural biological preservatives comprises the following raw materials in percentage by mass:

[0017]

[0018]

[0019] Furthermore, the emulsified flavor containing natural biological preservatives comprises the following raw materials in percentage by mass:

[0020]

[0021] The present invention also provides a method for preparing an emulsified flavor containing a natural biological preservative, comprising the following steps:

[0022] (1) taking citric acid and part of deionized water, heating them to 80-85° C. for sterilization, then lowering the temperature to 60-80° C., adding modified starch and / or gum arabic, and stirring at 60-80° C. for not less than 30 minutes; then turning off the heating, adding lactic acid and continuing stirring for 3-4 hours to obtain an emulsified aqueous phase solution;

[0023] (2) The aqueous solution of the emulsified aqueous phase obtained in step (1) is subjected to high-speed centrifugation for 1-2 times using a centrifuge such as a butterfly centrifuge (workshop) or a refrigerated centrifuge (laboratory), and the bottom precipitate is discarded and the supernatant is taken to obtain an emulsified aqueous phase for standby use;

[0024] (3) preheating caprylic acid glyceryl ester to 80-85° C., adding rosin glyceryl ester while stirring at this temperature, controlling the dissolution temperature at 60-70° C., and continuing stirring until the rosin glyceryl ester is completely dissolved; then filtering with a gauze while hot to obtain an emulsified oil phase;

[0025] (4) adding the polylysine hydrochloride-glycerol preparation, the natamycin-β-cyclodextrin powder preparation and nisin to the filtrate obtained in step (2), and then adding the remaining deionized water and stirring and mixing to obtain an emulsified aqueous phase containing a natural biological preservative;

[0026] (5) heating the emulsified oil phase obtained in step (3) to 55-65° C. for sterilization; starting stirring and adding dropwise to the emulsified water phase obtained in step (4); after the emulsified oil phase is added, stirring and shearing are started again for 30-60 minutes, and then high-pressure homogenization is performed for 2-3 times to obtain an emulsified flavor containing a natural biological preservative.

[0027] The preparation method of the emulsion flavor containing natural biological preservatives of the present invention has simple process, convenient operation and control, high production efficiency and is conducive to industrialization; the natural biological preservatives used in the emulsion flavor do not contain chemical preservatives, can effectively inhibit the growth of microorganisms and ensure food safety.

[0028] Furthermore, in step (1), citric acid and part of deionized water are taken and heated to 80-85° C. for pasteurization, and the sterilization time is not less than 10 minutes.

[0029] In the further step (5), the emulsified oil phase obtained in step (3) is heated to 55-65° C. for pasteurization, and the sterilization time is not less than 30 minutes.

[0030] Furthermore, in the step (5), the dropping speed of the emulsified oil phase is controlled at 100-200 kg / h, and the dropping time is controlled at 30-60 min.

[0031] Another object of the present invention is achieved by the following technical solution: A method for testing the antibacterial properties of an emulsified flavor, comprising the following steps:

[0032] A1. Inoculation of mold to accelerate the challenge: Pour the milky essence sample into the culture container, take the mold spore liquid and add it to the culture container, seal the culture container and place it in a 27-33℃ constant temperature shaker for culture, then take it out and shake it again, then place it in the room to stand for the microbial coating test;

[0033] A2. Use the spreading method to count mold on Red Bengal plates: In a microbial clean environment, take the inoculated and cultured sample and place it in an agar culture dish containing Red Bengal, spread it evenly, and then invert it in a 27-33℃ constant temperature incubator for culture. Then take out the culture dish to observe and count the mold growth in it; regularly retest the mold inhibition of relevant accelerated challenge samples;

[0034] A3. Total colony count: According to GB 4789.2-2022 National Food Safety Standard - Determination of Total Colony Count for Food Microbiological Examination, the total colony count on PCR agar plates, the mold and yeast count on Bengal red agar plates, and the Escherichia coli culture count on VRBA agar plates of the emulsion flavor concentrate shall be performed regularly (0-12 months) during the shelf life to test the total colony count and Escherichia coli, mold and yeast counts in the samples.

[0035] Furthermore, in the step A1, 100-150 g of the milky flavor sample is poured into the culture container, 8-12 μL of the mold spore liquid is added to the culture container, the culture container is sealed with a sterile biofilm and shaken evenly, and then placed in a 30°C constant temperature shaker for low-speed culture for 10-14 days, then taken out and shaken evenly again, and then placed indoors to stand for no less than 2 days.

[0036] Furthermore, in the step A2, in the microbial clean environment space, take 0.08-0.12 mL of the inoculated and cultured sample and place it in an agar culture dish containing Bengal red, spread it evenly, and then invert it in a 30°C constant temperature incubator for 3-5 days, then take out the culture dish to observe and count the mold reproduction therein; regularly retest the mold inhibition of the relevant accelerated challenge samples within 1-6 months.

[0037] The beneficial effects of the present invention are:

[0038] (1) The natural biological preservatives and the emulsion flavor containing the natural biological preservatives obtained by the method of the present invention, all the preservatives used are natural and / or biological preservatives legally allowed for use in food in accordance with GB2760, do not contain any chemical preservatives, and have obvious technical and product safety advantages;

[0039] (2) The natural biological preservatives of the present invention are compounded to form a new type of safe and efficient broad-spectrum preservative, which is a food preservative that can both kill bacteria and inhibit bacteria, and has an inhibitory effect on Gram-negative bacteria, Gram-positive bacteria, molds, yeasts, fungi and most microorganisms;

[0040] (3) The antibacterial testing method for the emulsion flavor containing natural biological preservatives of the present invention adopts a comprehensive microbial testing method combining mold inoculation accelerated challenge test and other microbial detection, which can effectively and quickly test the antiseptic inhibition effect of the emulsion flavor, and ultimately ensure the quality and safety of the product. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0042] Example 1

[0043] In this embodiment, a natural biological preservative includes the following raw materials in parts by weight: 0.4 parts of citric acid, 1 part of lactic acid, 0.1 parts of natamycin-β-cyclodextrin powder preparation, 0.2 parts of polylysine hydrochloride-glycerol preparation, and 0.05 parts of nisin.

[0044] In the embodiment of the present invention, the natamycin-β-cyclodextrin powder preparation can be selected from the commercial Namay sol (natamycin ≥ 12.5%) of Shandong Furuida Company; nisin and polylysine hydrochloride-glycerol preparations can be selected from commercial products commonly found in the market. Octenyl succinate starch sodium can be selected from the commercialized pure gum 1773 (PURITY GUM 1773), pure gum 2000 (PURITY GUM 2000), ultrapure gum (PURITY GUM ULTRA) and other models of Ingredion Company of the United States, and pure gum 2000 (PURITY GUM 2000) is selected in Examples 1-2. Gum arabic can be used as an emulsifier, and commercialized gum arabic Instantgum AA, Eficacia XE, SuperstabAA, Efisatb AA and other models of Nexira Company of France can be selected, and gum arabic Instantgum AA is selected in Examples 1-2.

[0045] In this embodiment, an emulsified flavor containing a natural biological preservative includes the following raw materials in percentage by weight:

[0046]

[0047]

[0048] The preparation method of the above-mentioned natural biological preservative-containing emulsion flavor comprises the following steps:

[0049] (1) Take citric acid and 2 / 3 of deionized water, heat to 82°C for pasteurization for 15 minutes, then reduce the temperature to 70°C, add sodium starch octenyl succinate, and keep stirring at 70°C; then turn off the heating, add lactic acid and continue stirring for 3.5 hours to obtain an emulsified aqueous phase solution;

[0050] (2) subjecting the aqueous solution of the emulsified aqueous phase obtained in step (1) to high-speed centrifugation twice, discarding the bottom precipitate and taking the supernatant to obtain an emulsified aqueous phase;

[0051] (3) preheating caprylic acid glyceryl ester to 82° C., adding rosin glyceryl ester while stirring at this temperature, controlling the dissolution temperature at 65° C., and continuing stirring until the rosin glyceryl ester is completely dissolved; then filtering while hot using a 200-mesh gauze to obtain an emulsified oil phase;

[0052] (4) adding the polylysine hydrochloride-glycerol preparation, the natamycin-β-cyclodextrin powder preparation and nisin to the filtrate obtained in step (2), and then adding the remaining deionized water and stirring and mixing to obtain an emulsified aqueous phase containing a natural biological preservative;

[0053] (5) raising the temperature of the emulsified oil phase obtained in step (3) to 60° C. for pasteurization for 30 min; starting stirring and adding dropwise to the emulsified water phase obtained in step (4), with the dropping speed controlled at 100-200 kg / h, and the addition being completed within 60 min. After the emulsified oil phase is added, high-speed stirring and shearing are started again for 30 min, and then high-pressure homogenization is performed twice to obtain an emulsified flavor containing a natural biological preservative.

[0054] Example 2

[0055] In this embodiment, a natural biological preservative includes the following raw materials in parts by weight: 0.4 parts of citric acid, 1 part of lactic acid, 0.1 parts of natamycin-β-cyclodextrin powder preparation, 0.2 parts of polylysine hydrochloride-glycerol preparation, and 0.05 parts of nisin.

[0056] In this embodiment, an emulsified flavor containing a natural biological preservative includes the following raw materials in percentage by weight:

[0057]

[0058] The preparation method of the above-mentioned natural biological preservative-containing emulsion flavor comprises the following steps:

[0059] (1) Take citric acid and 2 / 3 of deionized water, heat to 82°C for pasteurization for 15 minutes, then reduce the temperature to 70°C, add gum arabic, and keep stirring at 70°C; then turn off the heating, add lactic acid and continue stirring for 3.5 hours to obtain an emulsified aqueous phase solution;

[0060] (2) subjecting the aqueous solution of the emulsified aqueous phase obtained in step (1) to high-speed centrifugation twice, discarding the bottom precipitate and taking the supernatant to obtain an emulsified aqueous phase;

[0061] (3) preheating caprylic acid glyceryl ester to 82° C., adding rosin glyceryl ester while stirring at this temperature, controlling the dissolution temperature at 65° C., and continuing stirring until the rosin glyceryl ester is completely dissolved; then filtering while hot using a 200-mesh gauze to obtain an emulsified oil phase;

[0062] (4) adding the polylysine hydrochloride-glycerol preparation, the natamycin-β-cyclodextrin powder preparation and nisin to the filtrate obtained in step (2), and then adding the remaining deionized water and stirring and mixing to obtain an emulsified aqueous phase containing a natural biological preservative;

[0063] (5) raising the temperature of the emulsified oil phase obtained in step (3) to 60° C. for pasteurization for 30 min; starting stirring and adding dropwise to the emulsified water phase obtained in step (4), with the dropping speed controlled at 100-200 kg / h, and the addition being completed within 60 min. After the emulsified oil phase is added, high-speed stirring and shearing are started again for 30 min, and then high-pressure homogenization is performed twice to obtain an emulsified flavor containing a natural biological preservative.

[0064] Example 3

[0065] The accelerated challenge test and other microbial detection methods for the mildew and antibacterial properties of the emulsion flavor containing natural biological preservatives in Examples 1-2 specifically include the following steps:

[0066] A1. Inoculation of mold to accelerate the challenge: Pour 120g of the milky flavor sample into a 250mL conical flask (set the test group, blank group, and control group), use a pipette to take 10μL of mold spore liquid and add it to the conical flask, seal the bottle mouth with a sterile biofilm and shake it evenly by hand, then place it in a 30℃ constant temperature shaker for low-speed culture for 12 days, finally take it out and shake it evenly by hand again, then place it indoors for 3 days for the microbial coating test (Bengal Red Plate Mold Count).

[0067] A2. Mold count on Red Bengal plate (spreading method): In a microbial clean environment space (sterile biological operation table), use a pipette to take 0.1 mL of the inoculated sample and place it in an agar culture dish containing Red Bengal, spread it evenly, and then invert it in a 30℃ constant temperature incubator for 4 days. Finally, take out the culture dish to observe and count the mold reproduction; regularly retest the mold inhibition of the relevant accelerated challenge samples within 1-6 months.

[0068] A3. Total colony count (PCR plate count): According to GB 4789.2-2022 National Food Safety Standard - Determination of Total Colony Count for Food Microbiological Examination, the total colony count on PCR agar plates, the mold and yeast count on Bengal red agar plates, and the Escherichia coli culture count on VRBA agar plates of the emulsion flavors (stock solutions) containing natural biopreservatives shall be regularly counted during the shelf life (0-12 months) to test the total colony count and Escherichia coli, mold and yeast counts in the test samples.

[0069] In addition to the two embodiments, the present invention also provides comparative examples A, B, C, D, E, F, G (except for the necessary citric acid, only a single preservative is added and used, and the preparation process and microbiological testing method of each opaque flavor are consistent with the embodiments), and comparative example I (using chemical preservative potassium sorbate, the preparation process and microbiological testing method of the opaque flavor are consistent with embodiments 1-2). The specific dosages are shown in Table 1-2 below:

[0070] Table 1 Raw material ratios of the opacifying flavors of Examples 1-2 and Comparative Examples AD

[0071]

[0072] Table 2 Raw material ratio of the opacifying flavor of comparative example FI

[0073]

[0074]

[0075] The microbial test results of Examples 1-2 and Comparative Examples AI were compared, and the results are shown in Tables 3-4:

[0076] Table 3 Microbiological test results of the opacified flavor products of Examples 1-2 and Comparative Examples AD

[0077]

[0078] Table 4 Microbiological test results of the opacified flavor product of Comparative Example EI

[0079]

[0080] Among them: the accelerated challenge period after mold inoculation is 1-6 months, and the growth and reproduction of mold and mold count in the emulsion sample are tested based on the mold growth of the emulsion essence inoculated with mold and the special culture medium of Bengal red agar (containing chloramphenicol).

[0081] The testing cycle for total colony count and Escherichia coli is 0-12 months, in accordance with the detection methods of "GB 4789.2-2022 National Food Safety Standard Food Microbiology Inspection Determination of Total Colony Count" and "GB 4789.3-2016 National Food Safety Standard Food Microbiology Inspection Coliform Count", and the microbial index requirements of emulsified flavors in "GB30616-2020 Food Flavors" (total colony count (CFU / ml) ≤5000; coliform group (MPN / ml≤3.6) as the product qualification standard, otherwise it will be judged as "exceeding the standard", which means it does not meet the food quality and safety).

[0082] The testing cycle for mold and yeast is 0-12 months, in accordance with the detection method of "GB 4789.15-2016 National Food Safety Standard Food Microbiology Inspection Mold and Yeast Count", referring to the early "GB10355-2006 Food Additives Emulsified Flavors" microbial index requirements for mold and yeast (CFU / ml) ≤ 100 as the qualified standard (although the old standard GB10355 has been replaced and abolished by the new national standard GB30616, the special indicators of microorganisms for mold and yeast can be used as a reference).

[0083] Test results: From the comparison of the microbial results of Example 1, Example 2, Comparative Example A and Comparative Example I in Tables 3-4, it can be seen that the natural biological preservative compound used in the emulsion flavor containing natural biological preservatives prepared in this application can effectively replace the chemical preservatives such as potassium sorbate commonly used in the market. The natural biological preservative compounding technology adopted by the present invention can inhibit the reproduction and growth of microorganisms in the emulsion flavor for at least 12 months, ensuring compliance with food quality and safety standards.

[0084] Compared with Example 1, Example 2 and Comparative Examples AH, the natural biological preservative used in the present invention is a new type of safe and efficient broad-spectrum preservative, a food preservative that can both kill bacteria and inhibit bacteria, and has an inhibitory effect on most microorganisms such as molds, yeasts, Escherichia coli and bacteria.

[0085] The antibacterial test method of the natural biological preservative, the milky flavor and the natural biological preservative in the milky flavor of the present invention is adopted, and all the preservatives used are natural and / or biological preservatives legally allowed to be used in food in GB2760, and do not contain any chemical preservatives, which has obvious technical and product safety advantages. In addition, the accelerated challenge test of inoculated mold after the milky flavor of the present invention and other microbial detection methods can effectively and quickly test the anti-corrosion inhibition effect of food and ensure the quality and safety of food.

[0086] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A natural biological preservative, characterized in that: These include organic acids, natamycin, nisin and polylysine hydrochloride.

2. The natural biological preservative according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 0.3-2.5 parts of organic acid, 0.01-0.2 parts of natamycin-β-cyclodextrin powder preparation, 0.1-0.5 parts of polylysine hydrochloride-glycerol preparation and 0.01-0.08 parts of nisin.

3. An emulsified flavor containing the natural biological preservative according to any one of claims 1 to 2, characterized in that: The raw materials include the following mass percentages:

4. The emulsified flavor containing natural biological preservatives according to claim 3, characterized in that: The raw materials include the following mass percentages:

5. The emulsified flavor containing natural biological preservatives according to claim 3, characterized in that: The raw materials include the following mass percentages:

6. A method for preparing an emulsified flavor containing a natural biological preservative as claimed in claim 3, characterized in that: The steps include: (1) taking citric acid and part of deionized water, heating them to 80-85° C. for sterilization, then lowering the temperature to 60-80° C., adding modified starch and / or gum arabic, and stirring at 60-80° C.; then turning off the heating, adding lactic acid and continuing to stir to obtain an emulsified aqueous phase solution; (2) centrifuging the aqueous solution of the emulsified aqueous phase obtained in step (1), discarding the bottom precipitate and taking the supernatant to obtain an emulsified aqueous phase; (3) preheating caprylic acid glyceryl ester to 80-85° C., adding rosin glyceryl ester while stirring at this temperature, controlling the dissolution temperature at 60-70° C., and continuing stirring until the rosin glyceryl ester is completely dissolved; then filtering with a gauze while hot to obtain an emulsified oil phase; (4) adding the polylysine hydrochloride-glycerol preparation, the natamycin-β-cyclodextrin powder preparation and nisin to the filtrate obtained in step (2), and then adding the remaining deionized water and stirring and mixing to obtain an emulsified aqueous phase containing a natural biological preservative; (5) heating the emulsified oil phase obtained in step (3) to 55-65° C. for sterilization; starting stirring and adding dropwise to the emulsified water phase obtained in step (4); starting stirring and shearing again after the emulsified oil phase is added, and then performing high-pressure homogenization to obtain an emulsified flavor containing a natural biological preservative.

7. The method for preparing an emulsified flavor containing a natural biological preservative according to claim 6, characterized in that: In the step (1), citric acid and part of deionized water are taken and heated to 80-85° C. for pasteurization, and the sterilization time is not less than 10 minutes.

8. A method for testing the antibacterial properties of an emulsified flavor, characterized in that: The steps include: A1. Inoculation of mold to accelerate the challenge: Pour the milky essence sample into the culture container, take the mold spore liquid and add it to the culture container, seal the culture container and place it in a 27-33℃ constant temperature shaker for culture, then take it out and shake it again, then place it in the room to stand for the microbial coating test; A2. Use the spreading method to count mold on Red Bengal plates: In a microbial clean environment, take the inoculated and cultured sample and place it in an agar culture dish containing Red Bengal, spread it evenly, and then invert it in a 27-33℃ constant temperature incubator for culture. Then take out the culture dish to observe and count the mold growth in it; regularly retest the mold inhibition of relevant accelerated challenge samples; A3. Total colony count: Regularly count the total colony count on PCR agar plates, count mold and yeast on Bengal red agar plates, and count E. coli on VRBA agar plates for the emulsion flavor concentrate during the shelf life to test the total colony count and E. coli, mold and yeast counts in the samples.

9. The antibacterial testing method of the emulsified flavor according to claim 8, characterized in that: In the step A1, 100-150 g of the milky flavor sample is poured into the culture container, 8-12 μL of the mold spore liquid is added to the culture container, the culture container is sealed with a sterile biofilm and shaken evenly, and then placed in a 30° C. constant temperature shaker for low-speed culture for 10-14 days, then taken out and shaken evenly again, and then placed indoors to stand for no less than 2 days.

10. The antibacterial testing method of the emulsion flavor according to claim 8, characterized in that: In the step A2, in the microbial clean environment space, take 0.08-0.12 mL of the inoculated and cultured sample and place it in an agar culture dish containing Bengal red, spread it evenly, and then invert it in a 30°C constant temperature incubator for culture for 3-5 days, then take out the culture dish to observe and count the mold reproduction therein; regularly retest the mold inhibition of the relevant accelerated challenge samples within 1-6 months.

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