A method for sterilizing bee pollen

Abstract

The application belongs to the technical field of food sterilization and discloses a bee pollen sterilization method, which comprises the following steps: step 1, drying fresh bee pollen, and cooling the dried bee pollen to room temperature to obtain dried bee pollen for standby; and step 2, uniformly spraying ethanol on the surface of the dried bee pollen, and then performing plasma treatment; wherein the spraying amount of the ethanol is 0.1-0.3 mL / g; and the voltage of the plasma treatment is 40-70 kV. The application uses the plasma sterilization technology to cooperate with ethanol to perform sterilization, and the sterilization has the advantages of short sterilization time, low energy consumption, low processing temperature, high-efficiency sterilization of generated active substances, and low oxidation degree of the bee pollen, so that the biological activity and nutritional quality of the bee pollen are greatly retained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food sterilization, and in particular to a bee pollen sterilization method. BACKGROUND

[0002] Bee pollen refers to pollen pellets carried back by bees when collecting nectar, which forms pollen after storage and fermentation in the beehive. Bee pollen mainly contains protein, vitamin B, amino acid, bee pollen, thiamine, riboflavin, pyridoxol, pantothenic acid, nicotinic acid, active enzyme, flavonoids, lipids, nucleic acid, brassinosteroid, phytic acid, vitamin C, vitamin A, vitamin E, vitamin K, SOD, etc. It also contains potassium, magnesium, calcium, iron, silicon, phosphorus and other inorganic salts, trace elements and enzymes, and therefore has the effects of beautifying and improving blood lipids. However, bee pollen is often contaminated by microorganisms during collection and storage. When the pollen is exposed to the natural environment, it is easily contaminated by various microorganisms, and the microorganisms and secretions carried by bees during collection also easily contaminate the pollen. Therefore, in order to ensure the edible safety of bee pollen, it is necessary to sterilize the bee pollen.

[0003] At present, the sterilized bee pollen on the market mainly uses irradiation sterilization technology. Irradiation sterilization refers to exposing food to ionizing radiation to eliminate microorganisms, bacteria, viruses or small insects on the food. After the gamma rays generated by ionizing radiation interact with the substance, a part of the energy is transferred to the molecules or atoms of the substance, and the molecules or atoms become ions. These ions produce physical, chemical and biological reactions in the food. Irradiation sterilization mainly kills pathogenic microorganisms through two aspects: direct action and indirect action. Direct action refers to the damage of rays to several components of cells, including nucleic acids, proteins, lipids and other biological macromolecules, which causes ionization, excitation and chemical bond rupture, which not only randomly causes cell structure damage and function loss, but also makes the microorganisms lose the ability of replication or regeneration. Indirect action is to first make water molecules undergo radiolysis to form hydroxyl radicals, hydrated electrons, hydrogen peroxide and other strong oxidizing or reducing charged substances, which then act on biological macromolecules to cause structural damage, thereby damaging the activity of the organism. 60 Co-ray irradiation for sterilization of bee pollen can effectively kill microorganisms in bee pollen, has the advantages of high efficiency and no temperature rise, and is a relatively ideal sterilization technology for sterilization of bee pollen at present.

[0004] However, 60Co-γ irradiation uses radionuclides with strong radioactivity, which requires certain safety precautions to prevent leakage. In actual application, in order to achieve better sterilization effect, producers often exceed the irradiation dose. High-dose irradiation will change the nutritional components of food, such as cross-linking degradation of protein, lipid oxidation, and increased trans fatty acid content. Moreover, in actual production, the irradiated pollen will have a noticeable rancid smell after opening. This rancid smell is mainly caused by the unpleasant odor produced by lipid oxidation and decomposition of sulfur-containing amino acids. Therefore, it is used 60 The Co-γ irradiation method for sterilizing bee pollen is difficult to ensure the quality and safety of irradiated products. Consumers are sensitive to irradiation technology and are not very receptive to irradiated food. Some consumers have a resistance to it, which has brought certain restrictions to the production, sales, import and export trade of irradiated food. Therefore, it is very important to provide a new bee pollen sterilization method that can effectively sterilize and ensure food safety.

[0005] To this end, the present invention provides a bee pollen sterilization method. Summary of the Invention

[0006] In order to solve the problem of unpleasant odor and food safety when sterilizing food by the irradiation method used in the above-mentioned prior art, the present invention provides a bee pollen sterilization method, which comprises spraying ethanol and then immediately performing dielectric barrier discharge low-temperature plasma treatment. The dielectric barrier discharge low-temperature plasma synergizes with the ethanol to achieve effective sterilization of the bee pollen while ensuring food safety.

[0007] The bee pollen sterilization method of the present invention is achieved through the following technical solutions:

[0008] A bee pollen sterilization method comprises the following steps:

[0009] Step 1: Dry the fresh bee pollen and cool it to room temperature to obtain the dried bee pollen for later use;

[0010] Step 2, spraying ethanol evenly on the surface of the dried bee pollen, and then performing plasma treatment;

[0011] Wherein, the spraying amount of the ethanol is 0.1-0.3 mL / g;

[0012] The voltage of the plasma treatment is 40-70 kV.

[0013] Furthermore, the plasma treatment is performed using air as the ionized gas and dielectric barrier discharge atmospheric low-temperature plasma technology.

[0014] Furthermore, in step 2, the mass concentration of the ethanol is 70% to 80%.

[0015] Further, in step 2, the time of the plasma treatment is 2-10 min.

[0016] Further, the voltage of the plasma treatment is 50-60 kV.

[0017] Further, the spraying amount of the ethanol is 0.2 mL / g.

[0018] Further, in step 1, the drying treatment is performed by vacuum drying.

[0019] Further, the temperature of the vacuum drying is 30-50℃, and the drying time is 20-60 min.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The present application uses the combined treatment technology of vacuum drying, ethanol and plasma to sterilize the bee pollen. The combined treatment of ethanol and DBD-ACP has a synergistic effect, which can significantly enhance the sterilization effect on the bee pollen. During the plasma treatment, peracetic acid is generated in the ethanol solution sprayed on the surface of the bee pollen, and the generated peracetic acid can uniformly and fully contact the bee pollen, and can inactivate the microorganisms in the bee pollen by attacking the cell membrane, oxidizing amino acids, damaging nucleic acids and other ways, so as to realize sterilization by the synergistic effect of ethanol and plasma. At the same time, the present application takes into account that high-concentration ethanol is volatile, so when the plasma treatment is performed immediately after spraying the ethanol solution, the gas-phase humidity of the ionized gas during the plasma treatment is increased, so that the plasma can react with water in the ethanol solution to generate active oxygen free radicals with sterilization effect. At the same time, it is found that active oxygen free radicals dissolved in water can prolong the life of free radicals. Therefore, increasing the gas-phase humidity can enhance the sterilization effect of the plasma, which is an important reason why the combined treatment of ethanol solution and plasma shows a synergistic effect.

[0022] And the present application uses the treatment method of spraying ethanol first and then performing DBD-ACP sterilization, which has the most significant sterilization effect. Compared with ACP alone, the sterilization effect on E. coli and S. aureus is increased by 59.48% and 84.48%, respectively. And the present application performs 30-50℃ vacuum drying treatment on the bee pollen before the combined treatment of ethanol and plasma, which can significantly reduce the negative impact of plasma technology on the quality of the bee pollen. The increments of malondialdehyde and H2O2, which represent the degree of lipid oxidation and oxidative stress, are decreased by 75.77% and 44.29%, respectively. And through the verification of the examples, under the voltage of 60 kV and the treatment time of 6 min, the number of E. coli and S. aureus in the bee pollen is decreased by 1.16 and 0.58 log 10CFU / g, indicating that the treatment method of the application has a significant sterilization effect on bee pollen.

[0023] The application uses plasma sterilization technology in cooperation with ethanol for sterilization, and has the advantages of short sterilization time, low energy consumption, low processing temperature, high-efficiency sterilization of active substances and no easy residue, and greatly retains the quality of food. Compared with the current irradiation sterilization technology, the plasma equipment is more simple and safe, avoids the danger of irradiation nuclide leakage, and the treated bee pollen also has no safety hazards of residual radioactive substances. Vacuum drying treatment is performed on the bee pollen before ethanol and plasma combined sterilization, which significantly reduces the negative impact of sterilization on the quality of bee pollen. The bee pollen treated by plasma has no obvious bad smell, and has little effect on sensory and nutritional ingredients. Using plasma technology for bee pollen sterilization, to some extent, relieves the negative impact caused by the consumers' resistance to irradiated food, and is conducive to the sales and promotion of bee pollen products. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The content of E. coli in fresh bee pollen treated by examples 1-4, examples 5-13 and comparative example 1 is shown in Table 1.

[0025] Figure 2 The content of S. aureus in fresh bee pollen treated by examples 1-4, examples 5-13 and comparative example 1 is shown in Table 2.

[0026] Figure 3 The content of E. coli in fresh bee pollen treated by comparative examples 14-26 of the application is shown in Table 3.

[0027] Figure 4 The content of S. aureus in fresh bee pollen treated by comparative examples 14-26 of the application is shown in Table 4.

[0028] Figure 5 The content of E. coli in fresh bee pollen treated by examples 1-4 and comparative examples 28-31 of the application is shown in Table 5.

[0029] Figure 6 The content of S. aureus in fresh bee pollen treated by examples 1-4 and comparative examples 28-31 of the application is shown in Table 6.

[0030] Figure 7 The test results of malondialdehyde in bee pollen treated by examples 1-4, comparative examples 10-13 and comparative examples 19-22 of the application are shown in Table 7.

[0031] Figure 8 The test results of H2O2 in bee pollen treated by examples 1-4, comparative examples 10-13 and comparative examples 19-22 of the application are shown in Table 8. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below.

[0033] The present application provides a method for sterilizing bee pollen, comprising the following steps:

[0034] Step 1, dry the fresh bee pollen, and after cooling to room temperature, obtain the dried bee pollen, and reserve it for use;

[0035] It should be noted that the bee pollen must be dried before sterilization, and the preferred method is vacuum drying, which reduces the water content in the bee pollen wall and increases the humidity of the gas phase outside the wall, so as to avoid the interaction between water molecules in the bee pollen and plasma jet during subsequent plasma treatment, resulting in a decrease in the concentration of liquid phase ROS (reactive oxygen) and RNS (reactive nitrogen) generated, and thus causing ineffective sterilization. The temperature of the vacuum drying is 30-50℃, and the drying time is 20-60min.

[0036] And in order to avoid the high temperature of the dried bee pollen, it must be cooled to room temperature before spraying the ethanol solution, so as to avoid the high temperature of the bee pollen affecting the subsequent ethanol treatment.

[0037] Step 2, evenly spray ethanol on the surface of the dried bee pollen, and then perform plasma treatment;

[0038] It should be noted that in order to ensure the sterilization effect of the synergistic action of the ethanol solution and plasma treatment, the preferred ethanol has a mass concentration of 70%-80%, and is evenly sprayed on the surface of the dried bee pollen at a spraying amount of 0.1-0.3mL / g, and then rapidly treated by plasma.

[0039] In order to ensure the sterilization effect, the present application uses air as the ionizing gas and adopts dielectric barrier discharge atmospheric low-temperature plasma technology for plasma treatment, and the voltage for plasma treatment is 40-70kV, and the treatment time is 2-10min, so that the ethanol cooperates with the plasma to jointly sterilize the bee pollen.

[0040] Example 1

[0041] The present application provides a method for sterilizing bee pollen, comprising the following steps:

[0042] Place the fresh bee pollen in a vacuum drying oven at 40℃ for 30min, and after cooling to room temperature, obtain the dried bee pollen, and reserve it for use;

[0043] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the dried bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is rapidly subjected to plasma treatment at a voltage of 60 kV for 2 min, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0044] Example 2

[0045] The sterilization method of the bee pollen provided in the example comprises the following steps.

[0046] The fresh bee pollen is dried in a vacuum drying box at 40°C for 30 min, and after being cooled to room temperature, the dried bee pollen is obtained and prepared for use.

[0047] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the dried bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is rapidly subjected to plasma treatment at a voltage of 60 kV for 4 min, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0048] Example 3

[0049] The sterilization method of the bee pollen provided in the example comprises the following steps.

[0050] The fresh bee pollen is dried in a vacuum drying box at 40°C for 30 min, and after being cooled to room temperature, the dried bee pollen is obtained and prepared for use.

[0051] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the dried bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is rapidly subjected to plasma treatment at a voltage of 60 kV for 6 min, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0052] Example 4

[0053] The sterilization method of the bee pollen provided in the example comprises the following steps.

[0054] The fresh bee pollen is dried in a vacuum drying box at 40°C for 30 min, and after being cooled to room temperature, the dried bee pollen is obtained and prepared for use.

[0055] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the dried bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is rapidly subjected to plasma treatment at a voltage of 60 kV for 10 min, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0056] Example 5

[0057] The embodiment provides a bee pollen sterilization method, which comprises the following steps:

[0058] Fresh bee pollen is dried in a vacuum drying box at 40 DEG C for 30 min, and after cooling to room temperature, dried bee pollen is obtained and reserved;

[0059] 75% ethanol with a spraying amount of 0.1 mL / g is uniformly sprayed on the surface of the dried bee pollen, and then the bee pollen is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 40 kV, and the treatment time is 6 min, so that the sterilization treatment of the bee pollen is realized, and sterilized bee pollen is obtained.

[0060] Embodiment 6

[0061] The embodiment provides a bee pollen sterilization method, which comprises the following steps:

[0062] Fresh bee pollen is dried in a vacuum drying box at 40 DEG C for 30 min, and after cooling to room temperature, dried bee pollen is obtained and reserved;

[0063] 75% ethanol with a spraying amount of 0.3 mL / g is uniformly sprayed on the surface of the dried bee pollen, and then the bee pollen is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 70 kV, and the treatment time is 6 min, so that the sterilization treatment of the bee pollen is realized, and sterilized bee pollen is obtained.

[0064] Embodiment 7

[0065] The embodiment provides a bee pollen sterilization method, which comprises the following steps:

[0066] Fresh bee pollen is dried in a vacuum drying box at 30 DEG C for 60 min, and after cooling to room temperature, dried bee pollen is obtained and reserved; 70% ethanol with a spraying amount of 0.1 mL / g is uniformly sprayed on the surface of the dried bee pollen, and then the bee pollen is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 50 kV, and the treatment time is 6 min, so that the sterilization treatment of the bee pollen is realized, and sterilized bee pollen is obtained.

[0067] Embodiment 8

[0068] The embodiment provides a bee pollen sterilization method, which comprises the following steps:

[0069] The fresh bee pollen is placed in a vacuum drying oven at 50°C for 20 min, and after cooling to room temperature, dried bee pollen is obtained for standby; 80% ethanol with a spraying amount of 0.3 mL / g is uniformly sprayed on the surface of the dried bee pollen, and then the bee pollen is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 6 min, so as to realize the sterilization treatment of the bee pollen, and obtain sterilized bee pollen.

[0070] Comparative Example 1

[0071] This comparative example is a blank control, that is, the fresh bee pollen is not subjected to any sterilization treatment.

[0072] Comparative Example 2

[0073] This comparative example provides a bee pollen sterilization method, comprising the following steps:

[0074] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 40 kV, and the treatment time is 2 min, so as to realize the sterilization treatment of the bee pollen, and obtain sterilized bee pollen.

[0075] Comparative Example 3

[0076] This comparative example provides a bee pollen sterilization method, comprising the following steps:

[0077] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 40 kV, and the treatment time is 4 min, so as to realize the sterilization treatment of the bee pollen, and obtain sterilized bee pollen.

[0078] Comparative Example 4

[0079] This comparative example provides a bee pollen sterilization method, comprising the following steps:

[0080] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 40 kV, and the treatment time is 6 min, so as to realize the sterilization treatment of the bee pollen, and obtain sterilized bee pollen.

[0081] Comparative Example 5

[0082] This comparative example provides a bee pollen sterilization method, comprising the following steps:

[0083] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 40 kV, and the treatment time is 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain sterilized bee pollen.

[0084] Comparative Example 6

[0085] This comparative example provides a bee pollen sterilization method, comprising the following steps:

[0086] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 50 kV, and the treatment time is 2 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0087] Comparative Example 7

[0088] The present comparative example provides a bee pollen sterilization method, comprising the following steps:

[0089] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 50 kV, and the treatment time is 4 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0090] Comparative Example 8

[0091] The present comparative example provides a bee pollen sterilization method, comprising the following steps:

[0092] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 50 kV, and the treatment time is 6 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0093] Comparative Example 9

[0094] The present comparative example provides a bee pollen sterilization method, comprising the following steps:

[0095] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 50 kV, and the treatment time is 10 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0096] Comparative Example 10

[0097] The present comparative example provides a bee pollen sterilization method, comprising the following steps:

[0098] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 2 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0099] Comparative Example 11

[0100] The present comparative example provides a bee pollen sterilization method, comprising the following steps:

[0101] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 4 min, so as to realize sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0102] Comparative Example 12

[0103] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0104] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 6 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0105] Comparative Example 13

[0106] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0107] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0108] Comparative Example 14

[0109] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0110] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0111] Comparative Example 15

[0112] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0113] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0114] Comparative Example 16

[0115] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0116] The fresh bee pollen is subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0117] Comparative Example 17

[0118] The present comparative example provides a method for sterilizing bee pollen, comprising the following steps:

[0119] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the fresh bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is subjected to plasma treatment for 6 min at a voltage of 60 kV, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0120] Comparative Example 18

[0121] The present comparative example provides a sterilization method of bee pollen, which comprises the following steps:

[0122] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the fresh bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is subjected to plasma treatment for 10 min at a voltage of 60 kV, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0123] Comparative Example 19

[0124] The present comparative example provides a sterilization method of bee pollen, which comprises the following steps:

[0125] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the fresh bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is subjected to plasma treatment for 2 min at a voltage of 60 kV, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0126] Comparative Example 20

[0127] The present comparative example provides a sterilization method of bee pollen, which comprises the following steps:

[0128] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the fresh bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is subjected to plasma treatment for 4 min at a voltage of 60 kV, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0129] Comparative Example 21

[0130] The present comparative example provides a sterilization method of bee pollen, which comprises the following steps:

[0131] The ethanol with a mass concentration of 75% is uniformly sprayed on the surface of the fresh bee pollen at a spraying amount of 0.2 mL / g, and then the bee pollen is subjected to plasma treatment for 6 min at a voltage of 60 kV, so that the sterilization treatment of the bee pollen is realized, and the sterilized bee pollen is obtained.

[0132] Comparative Example 22

[0133] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0134] The fresh bee pollen is uniformly sprayed with ethanol with a mass concentration of 75% at a spraying amount of 0.2 mL / g, and then rapidly subjected to plasma treatment at a voltage of 60 kV for 10 min, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0135] Comparative Example 23

[0136] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0137] The fresh bee pollen is subjected to plasma treatment at a voltage of 60 kV for 2 min, and then uniformly sprayed with ethanol with a mass concentration of 75% at a spraying amount of 0.2 mL / g, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0138] Comparative Example 24

[0139] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0140] The fresh bee pollen is subjected to plasma treatment at a voltage of 60 kV for 4 min, and then uniformly sprayed with ethanol with a mass concentration of 75% at a spraying amount of 0.2 mL / g, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0141] Comparative Example 25

[0142] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0143] The fresh bee pollen is subjected to plasma treatment at a voltage of 60 kV for 6 min, and then uniformly sprayed with ethanol with a mass concentration of 75% at a spraying amount of 0.2 mL / g, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0144] Comparative Example 26

[0145] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0146] The fresh bee pollen is subjected to plasma treatment at a voltage of 60 kV for 10 min, and then uniformly sprayed with ethanol with a mass concentration of 75% at a spraying amount of 0.2 mL / g, so as to realize the sterilization treatment of the bee pollen, and obtain the sterilized bee pollen.

[0147] Comparative Example 27

[0148] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0149] The fresh bee pollen is dried in a vacuum drying oven at 40°C for 30 min, and after cooling to room temperature, dried bee pollen is obtained, and the sterilized bee pollen is obtained.

[0150] Comparative Example 28

[0151] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0152] The fresh bee pollen is dried in a vacuum drying oven at 40°C for 30 min, and after cooling to room temperature, dried bee pollen is obtained, and then it is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 2 min, thereby achieving sterilization treatment of the bee pollen, and obtaining sterilized bee pollen.

[0153] Comparative Example 29

[0154] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0155] The fresh bee pollen is dried in a vacuum drying oven at 40°C for 30 min, and after cooling to room temperature, dried bee pollen is obtained, and then it is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 4 min, thereby achieving sterilization treatment of the bee pollen, and obtaining sterilized bee pollen.

[0156] Comparative Example 30

[0157] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0158] The fresh bee pollen is dried in a vacuum drying oven at 40°C for 30 min, and after cooling to room temperature, dried bee pollen is obtained, and then it is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 6 min, thereby achieving sterilization treatment of the bee pollen, and obtaining sterilized bee pollen.

[0159] Comparative Example 31

[0160] The present comparative example provides a sterilization method of bee pollen, comprising the following steps:

[0161] The fresh bee pollen is placed in a vacuum drying oven at 40℃ for drying for 30 min, and after cooling to room temperature, dried bee pollen is obtained, and then the dried bee pollen is rapidly subjected to plasma treatment, and the voltage of the plasma treatment is 60 kV, and the treatment time is 10 min, so that the sterilization treatment of the bee pollen is realized, and sterilized bee pollen is obtained.

[0162] Test part

[0163] The E. coli and S. aureus contents of the bee pollen treated in Examples 1-12 and Comparative Examples 1-3 are tested, and the tests are respectively as shown in Figures 1-8 .

[0164] (I) The influence of the voltage and time of plasma treatment on the sterilization effect

[0165] Figure 1 The E. coli content in the fresh bee pollen treated in the present application Comparative Examples 1-13 is Figure 2 The S. aureus content in the fresh bee pollen treated in the present application Comparative Examples 1-13 is, and Figure 1 and Figure 2 In Table 1, different lowercase letters indicate that there is a significant difference (P < 0.05) in the sterilization effect of different treatment times under the same treatment voltage.

[0166] It can be seen from Figure 1 and Figure 2 that the E. coli and S. aureus contents of the bee pollen treated by the sterilization method of the present application decrease significantly, especially when the voltage of the plasma treatment is 60 kV, the sterilization effect is best, and when the treatment time is 6 min, the number of E. coli and S. aureus in the bee pollen decreases by 1.16 and 0.58 log 10 CFU / g, respectively.

[0167] (II) The influence of ethanol treatment on the sterilization effect

[0168] Figure 3 The E. coli content in the fresh bee pollen treated in the present application Comparative Examples 14-26 is Figure 4 The S. aureus content in the fresh bee pollen treated in the present application Comparative Examples 14-26 is, and Figure 3 and Figure 4 In Table 2, different lowercase letters indicate that there is a significant difference (P < 0.05) in the sterilization effect of different treatment times under the same treatment voltage.

[0169] and from Figure 3 and Figure 4It can be seen that the combined treatment of ethanol (75% E) and plasma (ACP) on bee pollen significantly increases the sterilization effect on E. coli and S. aureus in bee pollen. Among them, the treatment method of spraying ethanol first and then immediately performing plasma sterilization has the most significant sterilization effect. When the spraying amount is 0.2 mL / g, the voltage is 60 kV, and the treatment time is 6 min, the number of E. coli and S. aureus in bee pollen decreases by 1.85 and 1.07 log 10 CFU / g, respectively. Compared with the above comparative examples 1-13, i.e. only plasma treatment, the sterilization effect of plasma treatment combined with ethanol spraying on E. coli and S. aureus is significantly improved, and increased by 59.48% and 84.48%, respectively. It shows that the order of spraying ethanol and plasma treatment has a significant effect on the sterilization effect, therefore, the application preferably uses the method of spraying ethanol first and then immediately performing plasma treatment to significantly improve the synergistic sterilization effect of ethanol and plasma treatment.

[0170] (III) The influence of drying treatment on sterilization effect

[0171] Figure 5 The content of E. coli in fresh bee pollen treated by the application examples 1-4 and comparative examples 28-31 is Figure 6 The content of S. aureus in fresh bee pollen treated by the application examples 1-4 and comparative examples 28-31 is, and Figure 5 and Figure 6 In the above table, different lowercase letters represent that there is a significant difference (P<0.05) in the sterilization effect of different treatment times under the same treatment voltage.

[0172] And from Figure 5 and Figure 6 It can be seen that when there is no ethanol treatment, directly vacuum drying and then performing plasma treatment on the bee pollen, the number of E. coli and S. aureus in the treated bee pollen only decreases by 0.47 and 0.17 log 10 CFU / g, respectively. While after the sterilization method of the application, i.e. vacuum drying, ethanol spraying and plasma treatment, E. coli and S. aureus are reduced by 1.28 and 0.66 log 10 CFU / g, respectively. And by comparing the treatment results of comparative examples 1-4 and the above comparative examples 1-27, it can be seen that the sterilization effect of the application is realized through the synergistic effect of vacuum drying, ethanol spraying and plasma treatment in turn.

[0173] (IV) Lipid oxidation degree and oxidative stress test

[0174] The application takes Examples 1-4, Comparative Examples 10-13 and Comparative Examples 19-22 as examples, tests the contents of malondialdehyde and H2O2 in the bee pollen treated by Examples 1-4, Comparative Examples 10-13 and Comparative Examples 19-22 of the application, to test the lipid oxidation degree and oxidative stress of the bee pollen (wherein malondialdehyde is used as an index of lipid oxidation degree, and H2O2 is used as an index of oxidative stress), and the test results are shown in Figure 7 and Figure 8 As shown in Figure 7 the test results of malondialdehyde in the bee pollen treated by Examples 1-4, Comparative Examples 10-13 and Comparative Examples 19-22 of the application, Figure 8 the test results of H2O2 in the bee pollen treated by Examples 1-4, Comparative Examples 10-13 and Comparative Examples 19-22 of the application.

[0175] and it can be known from Figure 7 and Figure 8 that the contents of malondialdehyde and H2O2 in the bee pollen treated by Examples 1-4 of the application are obviously lower than those treated by Comparative Examples 10-14 and Comparative Examples 19-22, and after the sterilization method of Examples 1-4 of the application, the vacuum drying, ethanol spraying and plasma treatment are sequentially performed, the contents of malondialdehyde and H2O2 only increase by 6.56 nmol / g and 15.08 μmol / g, and the increments decrease by 75.77% and 44.29% respectively, which significantly reduces the negative impact of plasma technology on the quality of bee pollen.

[0176] Based on the above, the application selects the dielectric barrier discharge (DBD) atmospheric low-temperature plasma (ACP) technology with a simpler structure, changes the indirect treatment mode of plasma-activated water to a more efficient direct treatment mode of DBD-ACP. With ordinary air as the ionization gas at a lower cost, a small amount of ethanol solution with high volatility is sprayed on the surface of the bee pollen, and then the plasma is directly treated. The plasma technology can be effectively applied to the sterilization of bee pollen, and also has the characteristics of simplicity, low cost and high efficiency. In addition, the application applies the vacuum drying technology to the bee pollen before plasma treatment, so as to reduce the water content in the wall of the bee pollen and increase the gas phase humidity outside the wall, which effectively alleviates the negative impact of sterilization on the quality of the bee pollen.

[0177] Obviously, the above examples are only part of the examples of the application, not all the examples. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor belong to the scope of protection of the application.

Claims

1. A bee pollen sterilization method, characterized in that: The following steps are involved: Step 1: Dry the fresh bee pollen and cool it to room temperature to obtain the dried bee pollen for later use; Step 2, spraying ethanol evenly on the surface of the dried bee pollen, and then performing plasma treatment; Wherein, the spraying amount of the ethanol is 0.1~0.3 mL / g; The plasma treatment uses air as the ionized gas and is performed using dielectric barrier discharge low-temperature plasma technology; In step 1, the drying process is carried out by vacuum drying; the vacuum drying temperature is 30-50° C., and the drying time is 20-60 min; In step 2, the plasma treatment time is 2 to 10 minutes; In step 2, the mass concentration of the ethanol is 70% to 80%; The voltage of the plasma treatment is 50-60 kV.

2. A bee pollen sterilization method according to claim 1, characterized in that: The spraying amount of the ethanol was 0.2 mL / g.

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