Surfactant for cleaning fruits and vegetables and preparation method thereof

Abstract

The invention discloses a surfactant for cleaning fruits and vegetables and a preparation method of the surfactant, and relates to the technical field of fruit and vegetable cleaning agents. Raw materials of the cleaning agent comprise the following components: 10-15 parts of a modified surfactant, 2-3 parts of an enzyme preparation, 1-2 parts of a cosolvent, 0.2-2 parts of a viscosity modifier, 0.1-0.5 part of a bactericidal preservative, 0.1-2.5 parts of a light stabilizer, 0.1-1.3 parts of an antioxidant, 0.3 part of an emulsifier, 0.05-0.2 part of a bacteriostatic substance, 0.1-0.8 part of sodium citrate, 5-7 parts of diatomite powder, 2-8 parts of a polyethylene glycol dispersant and 80-90 parts of deionized water. The preparation method comprises the following steps: firstly, adding a modified surfactant into deionized water, then sequentially adding an enzyme preparation, a cosolvent, a bactericidal preservative, a light stabilizer, an antioxidant, an emulsifier, a bacteriostatic substance, diatomite powder and a polyethylene glycol dispersant into a reaction kettle, and continuously stirring and mixing to form a solution A; the fruit and vegetable cleaning surfactant prepared by the preparation steps has excellent detergency and a low-temperature residual pesticide removal effect while having relatively good use safety.

Description

Technical Field

[0001] The invention relates to the technical field of fruit and vegetable cleaning agents, in particular to a surfactant for cleaning fruits and vegetables and a preparation method thereof. Background Art

[0002] The main raw material of fruit and vegetable cleaning agents is surface cleaning agents, which are mainly used to clean fruits and vegetables and remove residual pesticides, fertilizers and other dirt on the surface of fruits and vegetables. Existing surfactants used for fruit and vegetable cleaning are difficult to ensure that they have good safety in use and have excellent residual pesticide removal effects at low temperatures.

[0003] The defects of existing surfactant preparation are:

[0004] 1. Patent document CN107299007B discloses a biological fruit and vegetable cleaning agent and a preparation method thereof, which mainly considers how to degrade or kill pesticide residues, wax, pathogens, etc. in fruits and vegetables, but does not consider how to make the fruit and vegetable cleaning surfactant have better safety in use and improve its residual pesticide removal effect at low temperature;

[0005] 2. Patent document CN110511839B discloses a fruit and vegetable cleaning agent and a preparation method thereof. It mainly considers how to prepare a cleaning agent with better removal of pesticide residues, but does not consider how to reduce the irritation of surfactants to the skin and enhance the low-temperature washing effect;

[0006] 3. Patent document CN108865490B discloses a microemulsion-type fruit and vegetable cleaning agent for removing pesticide residues and a preparation method thereof. The patent mainly considers how to make the cleaning agent have a stable microemulsion liquid structure in addition to having a good ability to remove pesticide residues, but does not consider how to improve the decontamination adsorption ability of surfactants;

[0007] 4. Patent document CN110452776B discloses a food-grade fruit and vegetable cleaning agent and a method for making the same. It mainly considers how to effectively solve the defects of low protein utilization and single product, but does not consider how to further improve the ability of surfactants to remove pesticide residues on the basis of environmental protection. Summary of the invention

[0008] The object of the present invention is to provide a surfactant for washing fruits and vegetables and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solution: a surfactant for washing fruits and vegetables, wherein the raw materials thereof include the following components by weight: 10-15 parts of a modified surfactant, 2-3 parts of an enzyme preparation, 1-2 parts of a cosolvent, 0.2-2 parts of a viscosity regulator, 0.1-0.5 parts of a bactericidal preservative, 0.1-2.5 parts of a light stabilizer, 0.1-1.3 parts of an antioxidant, 0.3 parts of an emulsifier, 0.05-0.2 parts of an antibacterial substance, 0.1-0.8 parts of sodium citrate, 5-7 parts of diatomaceous earth powder, 2-8 parts of a polyethylene glycol dispersant, and 80-90 parts of deionized water;

[0010] The modified surfactant, enzyme preparation, cosolvent, viscosity regulator, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, sodium citrate, diatomaceous earth powder, polyethylene glycol dispersant and deionized water are mixed in proportion to prepare a fruit and vegetable cleaning surfactant. Compared with the traditional fruit and vegetable cleaning agent, the prepared fruit and vegetable cleaning surfactant has a better removal effect on residual pesticides in a low temperature environment.

[0011] Preferably, the modified surfactant is prepared by mixing fatty alcohol polyvinyl ether, sodium cocoyl glutamate and medium-chain alkanol in a mass ratio of (3-2):1:0.5.

[0012] Preferably, the particle size of the diatomaceous earth powder is 800-1000 mesh.

[0013] Preferably, the bactericidal preservative is one or more of nisin, natamycin, sodium benzoate and potassium sorbate, and the antibacterial substance is one or more of benzalkonium chloride and methylchloroisothiazolinone.

[0014] Preferably, the enzyme preparation is one or more of protease, lipase and amylase.

[0015] Preferably, the preparation method of the surfactant for washing fruits and vegetables is as follows:

[0016] Step S1: raw material preparation: diatomaceous earth is refined to obtain diatomaceous earth powder for later use;

[0017] Step S2: preparing a modified surfactant: adding fatty alcohol polyvinyl ether, sodium cocoyl glutamate and medium-chain alkanol into a reaction kettle in sequence, and mixing them thoroughly to prepare a modified surfactant for later use;

[0018] Step S3: Mixing preparation: uniformly mixing the modified surfactant obtained in step S2, the enzyme preparation, the cosolvent, the viscosity modifier, the bactericidal preservative, the light stabilizer, the antioxidant, the emulsifier, the antibacterial substance, the sodium citrate, the diatomaceous earth powder, the polyethylene glycol dispersant and the deionized water to prepare a viscous mixture;

[0019] Step S4: Filtration and drying: The viscous mixture obtained in step S3 is filtered under reduced pressure to remove insoluble impurities therein, and then the filtered mixture is freeze-dried in a vacuum environment to obtain a fruit and vegetable cleaning surfactant, wherein the freeze-drying treatment temperature is -5 to -2°C and the treatment time is 20 minutes;

[0020] Step S5: packaging and storage: packaging the prepared fruit and vegetable cleaning surfactant under sterile conditions;

[0021] Step S6: Quality inspection: testing the pH value of the prepared fruit and vegetable cleaning surfactant and its pesticide residue removal effect in a low temperature environment.

[0022] Preferably, the step S1 further includes the following steps:

[0023] Step S11: Preliminary crushing: Put the large pieces of diatomaceous earth into a hammer crusher, and use a high-speed rotating hammer to hit and impact the large pieces of diatomaceous earth to form small pieces of diatomaceous earth, wherein the speed of the hammer is 35m / s and the operation time is 10-15min;

[0024] Step S12: Grinding treatment: The small pieces of diatomaceous earth in step S11 are placed in a planetary ball mill and further ground into diatomaceous earth powder with a particle size of 800-1000 meshes.

[0025] Preferably, the step S2 further includes the following steps:

[0026] Step S21: Add fatty alcohol polyvinyl ether and medium-chain alkanol into a reaction kettle, and stir for 20-30 minutes at 30-40° C. to obtain a mixed solution;

[0027] Step S22: Then add sodium cocoyl glutamate to the mixed solution prepared in step S21, continue stirring for 15-20 minutes, and compound to obtain a modified surfactant.

[0028] Preferably, the step S3 further includes the following steps:

[0029] Step S31: adding deionized water into the reaction kettle for preheating to a temperature of 55-65° C.;

[0030] Step S32: adding the modified surfactant to the deionized water heated in step S31, stirring at a speed of 20-30 r / min for 5-10 min to mix evenly;

[0031] Step S33: Cool the mixed reagent obtained in step S32, and when the temperature drops to 35° C., add enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reaction kettle, stir at a speed of 30-40 r / min for 30 min under a constant temperature environment, and fully mix and dissolve to obtain solution A;

[0032] Step S34: Then, sodium citrate is added to the solution A obtained in step S33, and stirring is continued for 10-15 minutes. Then, a viscosity regulator is added, and stirring is continued for 15-20 minutes at a speed of 45 r / min to obtain a viscous mixture.

[0033] Preferably, the step S6 further includes the following steps:

[0034] Step S61: Determine the pH value of the fruit and vegetable cleaning surfactant using the potentiometric method specified in GB / T6368, take 5 g of a fruit and vegetable cleaning surfactant sample at room temperature and place it in a clean measuring cup, immerse the calibrated pH meter electrode in the sample, gently stir the sample, and record the pH value after the pH meter reading stabilizes;

[0035] Step S62: respectively, at -10°C, -5°C, 0°C, 5°C and 20°C, using

[0036] The inspection method specified in GB / T24691-2022 determines the removal rate of residual pesticides and comprehensively evaluates the removal effect of residual pesticides.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention preheats deionized water, then adds a modified surfactant to the deionized water, stirs to form a solution, then sequentially adds an enzyme preparation, a cosolvent, a bactericidal preservative, a light stabilizer, an antioxidant, an emulsifier, an antibacterial substance, diatomaceous earth powder and a polyethylene glycol dispersant into a reaction kettle, continues to stir and mix to form a solution A, and then adds sodium citrate after mixing to stabilize the pH value of the solution to prevent adverse reactions between the components, and adjusts the pH value to 6.5-7.5 so that the fruit and vegetable cleaning surfactant does not cause damage to the skin of human hands, and finally adds a viscosity regulator to adjust the rheological properties of the solution. The fruit and vegetable cleaning surfactant prepared by the preparation steps has good safety in use and excellent detergency and residual pesticide removal effect at low temperatures.

[0039] 2. The invention adds a medium-chain alkanol to a nonionic surfactant, and by increasing the solubility of the surfactant and maintaining its activity, the detergency of the nonionic surfactant at low temperature and the removal effect of fat-soluble pesticides can be significantly improved. Then, sodium cocoyl glutamate is added thereto and mixed evenly. Sodium cocoyl glutamate is a mild anionic surfactant with low irritation. By compounding the nonionic surfactant and the anionic surfactant, the synergistic effect between different types of surfactants can be utilized, and the low-temperature washing effect can be enhanced while effectively reducing skin irritation.

[0040] 3. The diatomaceous earth particles after grinding in the present invention are uniform and fine, so that the ideal particle size can be obtained while maintaining the special porous structure of the diatomaceous earth, which helps to improve the decontamination and adsorption capacity of the fruit and vegetable cleaning surfactant prepared subsequently.

[0041] 4. The present invention utilizes the decomposition catalytic ability of biological enzymes through enzyme preparations to effectively remove dirt and pesticide residues on fruits and vegetables, further improving the ability of surfactants to remove pesticide residues. In addition, antibacterial substances and bactericidal preservatives help to store the prepared fruit and vegetable cleaning surfactants, ensuring that bacteria will not grow and affect subsequent normal use, so that the subsequently prepared fruit and vegetable cleaning surfactants have good stability and are convenient for product storage. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The present invention provides a surfactant for cleaning fruits and vegetables and a preparation method thereof. The preparation method of the surfactant for cleaning fruits and vegetables is as follows:

[0044] Step S1: raw material preparation: large pieces of diatomaceous earth are placed in a hammer crusher, and the large pieces of diatomaceous earth are struck and impacted by a high-speed rotating hammer to form small pieces of diatomaceous earth, wherein the speed of the hammer is 35 m / s, and the running time is 10-15 min, and then the small pieces of diatomaceous earth are placed in a planetary ball mill and further ground into diatomaceous earth powder with a particle size of 800-1000 mesh;

[0045] Step S2: preparing a modified surfactant: firstly adding fatty alcohol polyvinyl ether and medium-chain alkanol into a reaction kettle, stirring for 20-30 min at 30-40° C. to obtain a mixed solution, then adding sodium cocoyl glutamate into the mixed solution, continuing to stir for 15-20 min, and compounding to obtain a modified surfactant;

[0046] Step S3: Mixing preparation: first add deionized water into a reactor for preheating treatment, heat to a temperature of 55-65°C, then add the modified surfactant to the heated deionized water, stir at a speed of 20-30r / min for 5-10min to mix them evenly, then cool the mixed reagents, and when the temperature drops to 35°C, add enzyme preparations, cosolvents, bactericidal preservatives, light stabilizers, antioxidants, emulsifiers, antibacterial substances, diatomaceous earth powder and polyethylene glycol dispersants into the reactor, stir at a speed of 30-40r / min for 30min under a constant temperature environment, fully mix and dissolve to obtain solution A, then add sodium citrate to the obtained solution A, continue stirring for 10-15min, then add a viscosity regulator, continue stirring at a speed of 45r / min for 15-20min to obtain a viscous mixture;

[0047] Step S4: Filtration and drying: The viscous mixture obtained in step S3 is filtered under reduced pressure to remove insoluble impurities therein, and then the filtered mixture is freeze-dried in a vacuum environment to obtain a fruit and vegetable cleaning surfactant, wherein the freeze-drying treatment temperature is -5 to -2°C and the treatment time is 20 minutes;

[0048] Step S5: packaging and storage: packaging the prepared fruit and vegetable cleaning surfactant under sterile conditions.

[0049] Furthermore, diatomaceous earth can absorb impurities such as pesticides and dust in fruits and vegetables through its special structure. First, a hammer crusher is used to impact large pieces of diatomaceous earth into small pieces at high speed, and then a planetary ball mill is used to quickly crush the material through extremely high centrifugal force. The ground diatomaceous earth particles are uniform and fine, so that the ideal particle size can be obtained while maintaining the special porous structure of diatomaceous earth, which helps to improve the decontamination and adsorption capacity of the fruit and vegetable cleaning surfactant prepared later;

[0050] Fatty alcohol polyvinyl ether is a nonionic surfactant. Nonionic surfactants will not dissociate into ions in water and are not affected by the pH value of the solution. They have high stability. Nonionic surfactants are less irritating and safer to use. They will not cause damage to the skin of human hands. At the same time, since nonionic surfactants are not charged, they can be mixed with most other types of surfactants to improve the overall performance of the formula. By adding medium-chain alkanols to nonionic surfactants, the solubility of surfactants is increased and their activity is maintained, which can significantly improve the detergency of nonionic surfactants at low temperatures and the removal effect of fat-soluble pesticides, thereby enhancing the interaction between surfactants and pesticides. The effect of the invention is conducive to the formation of the lamellar liquid crystal Lα phase, thereby improving the washing efficiency. At the same time, since the medium-chain alkanol can help the non-ionic surfactant to more effectively solubilize grease and dirt and disperse them in water, the redeposition of dirt on the surface of the object can be reduced, thereby improving the cleaning efficiency. Then, sodium cocoyl glutamate is added thereto and mixed evenly. Sodium cocoyl glutamate is a mild anionic surfactant with low irritation. By compounding the non-ionic surfactant and the anionic surfactant, the synergistic effect between different types of surfactants can be utilized to effectively reduce skin irritation while enhancing the low-temperature washing effect. The prepared modified surfactant has a better cleaning effect than a single surfactant.

[0051] First, preheat the deionized water, then add the modified surfactant into the deionized water, stir evenly to form a solution, then add the enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reaction kettle in turn, continue to stir and mix to form solution A, diatomaceous earth has an adsorption effect, and can adsorb impurities such as pesticides and dust in fruits and vegetables, and the polyethylene glycol dispersant helps to fully disperse the diatomaceous earth powder in the modified surfactant solution to give full play to the adsorption effect of diatomaceous earth, the emulsifier component in the fruit and vegetable cleaning surfactant can decompose oil stains and turn substances that are difficult to dissolve in water into easily soluble substances, thereby making it easy to separate from the object to be cleaned, and the enzyme preparation utilizes the raw material to absorb the impurities such as pesticides and dust in fruits and vegetables. The decomposition catalytic ability of the enzyme can effectively remove the dirt and pesticide residues on the fruits and vegetables. The antibacterial substance and the bactericidal preservative are helpful for the storage of the prepared fruit and vegetable cleaning surfactant to ensure that bacteria will not grow and affect the subsequent normal use. After mixing evenly, sodium citrate is added to stabilize the pH value of the solution to prevent adverse reactions between the components, and the pH value is adjusted to 6.5-8.5, so that the fruit and vegetable cleaning surfactant will not cause damage to the skin of human hands. Finally, a viscosity regulator is added to adjust the rheological properties of the solution and change the viscosity of the solution. The fruit and vegetable cleaning surfactant prepared by the preparation step has good safety in use and excellent detergency and residual pesticide removal effect at low temperature;

[0052] The insoluble impurities or unmixed components that may exist in the fruit and vegetable cleaning surfactant are removed by filtering and drying to ensure the purity of the final product. The product is packaged under sterile conditions to prevent contamination and degradation. The packaged product is generally stored in a cool and dry place to ensure the stability and long-term effectiveness of the product. In order to reduce environmental pollution, recyclable materials are used to make packaging and reduce the use of plastics and other non-degradable substances. Finally, quality inspection is carried out according to the relevant documents on surfactants and cleaning agents issued by the State Administration for Market Regulation;

[0053] The value in step S3 is changed, and steps S1-2 and S4-5 are performed. The pH value and the residual pesticide removal rate at low temperature of the prepared fruit and vegetable cleaning surfactant are tested, and the residual pesticide removal effect of the fruit and vegetable cleaning surfactant in a low temperature environment is comprehensively evaluated.

[0054] Embodiment 1:

[0055] Step S3: Mixing preparation: first add deionized water into the reactor for preheating treatment, heat it to a temperature of 60°C, then add the modified surfactant into the heated deionized water, stir it at a speed of 25r / min for 10min to mix it evenly, then cool the mixed reagents until the temperature drops to 35°C, add enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reactor, stir it at a speed of 40r / min for 30min under a constant temperature environment, The mixture was fully mixed and dissolved to obtain solution A, and then sodium citrate was added to the obtained solution A, and stirring was continued for 15 minutes. Then, a viscosity regulator was added, and stirring was continued for 15 minutes at a speed of 45 r / min to obtain a viscous mixture, wherein the mass ratio of modified surfactant, enzyme preparation, cosolvent, viscosity regulator, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, sodium citrate, diatomaceous earth powder, polyethylene glycol dispersant and deionized water was 11:2:1:1:0.3:0.8:0.5:0.3:0.1:0.3:5:5:84.

[0056] Further, it was found that the pH was 6.6, the residual pesticide removal rate at -10°C was 79%, the residual pesticide removal rate at -5°C was 82%, the residual pesticide removal rate at 0°C was 84%, the residual pesticide removal rate at 5°C was 89%, and the residual pesticide removal rate at 20°C was 92%. The comprehensive evaluation of the residual pesticide removal effect at low temperature was good.

[0057] Embodiment 2:

[0058] Step S3: Mixing preparation: first add deionized water into the reactor for preheating treatment, heat it to a temperature of 60°C, then add the modified surfactant into the heated deionized water, stir it at a speed of 25r / min for 10min to mix it evenly, then cool the mixed reagents until the temperature drops to 35°C, add enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reactor, stir it at a speed of 40r / min for 30min under a constant temperature environment, The mixture was fully mixed and dissolved to obtain solution A, and then sodium citrate was added to the obtained solution A, and stirring was continued for 15 minutes. Then, a viscosity regulator was added, and stirring was continued for 15 minutes at a speed of 45 r / min to obtain a viscous mixture, wherein the mass ratio of modified surfactant, enzyme preparation, cosolvent, viscosity regulator, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, sodium citrate, diatomaceous earth powder, polyethylene glycol dispersant and deionized water was 12:2:1:1:0.3:0.8:0.5:0.3:0.1:0.3:6:5:88.

[0059] Further, it was found that the pH was 6.7, the residual pesticide removal rate at -10°C was 80%, the residual pesticide removal rate at -5°C was 82%, the residual pesticide removal rate at 0°C was 85%, the residual pesticide removal rate at 5°C was 90%, and the residual pesticide removal rate at 20°C was 94%. The comprehensive evaluation of the residual pesticide removal effect at low temperature was good.

[0060] Embodiment three:

[0061] Step S3: Mixing preparation: first add deionized water into the reactor for preheating treatment, heat it to a temperature of 60°C, then add the modified surfactant into the heated deionized water, stir it at a speed of 25r / min for 10min to mix it evenly, then cool the mixed reagents until the temperature drops to 35°C, add enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reactor, stir it at a speed of 40r / min for 30min under a constant temperature environment, The mixture was fully mixed and dissolved to obtain solution A, and then sodium citrate was added to the obtained solution A, and stirring was continued for 15 minutes. Then, a viscosity regulator was added, and stirring was continued for 15 minutes at a speed of 45 r / min to obtain a viscous mixture, wherein the mass ratio of the modified surfactant, enzyme preparation, cosolvent, viscosity regulator, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, sodium citrate, diatomaceous earth powder, polyethylene glycol dispersant and deionized water was 13:3:1:1:0.3:0.8:0.5:0.3:0.1:0.3:6:5:88.

[0062] Further, it was found that the pH was 7.1, the residual pesticide removal rate at -10°C was 85%, the residual pesticide removal rate at -5°C was 88%, the residual pesticide removal rate at 0°C was 89%, the residual pesticide removal rate at 5°C was 93%, and the residual pesticide removal rate at 20°C was 97%. Comprehensive evaluation of the residual pesticide removal effect at low temperature: good.

[0063] Comparative Example:

[0064] Take Liby cleaning agent sold on the market as a comparative example, with pH value: 6.1, residual pesticide removal rate at -10℃: 34%, residual pesticide removal rate at -5℃: 43%, residual pesticide removal rate at 0℃: 61%, residual pesticide removal rate at 5℃: 78%, residual pesticide removal rate at 20℃: 91%. Comprehensive evaluation of residual pesticide removal effect at low temperature: poor.

[0065] The test results of the pH value of fruit and vegetable cleaning surfactants and the removal effect of pesticide residues in a low temperature environment are as follows:

[0066]

[0067]

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A surfactant for cleaning fruits and vegetables, Features: The raw materials include the following components by weight: 10-15 parts of modified surfactant, 2-3 parts of enzyme preparation, 1-2 parts of cosolvent, 0.2-2 parts of viscosity regulator, 0.1-0.5 parts of bactericidal preservative, 0.1-2.5 parts of light stabilizer, 0.1-1.3 parts of antioxidant, 0.3 parts of emulsifier, 0.05-0.2 parts of antibacterial substance, 0.1-0.8 parts of sodium citrate, 5-7 parts of diatomaceous earth powder, 2-8 parts of polyethylene glycol dispersant, and 80-90 parts of deionized water; The modified surfactant, enzyme preparation, cosolvent, viscosity regulator, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, sodium citrate, diatomaceous earth powder, polyethylene glycol dispersant and deionized water are mixed in proportion to prepare a fruit and vegetable cleaning surfactant. Compared with the traditional fruit and vegetable cleaning agent, the prepared fruit and vegetable cleaning surfactant has a better removal effect on residual pesticides in a low temperature environment.

2. A surfactant for washing fruits and vegetables according to claim 1, Features: The modified surfactant is prepared by mixing fatty alcohol polyvinyl ether, sodium cocoyl glutamate and medium-chain alkanol in a mass ratio of (3-2):1:0.

5.

3. A surfactant for washing fruits and vegetables according to claim 1, Features: The particle size of the diatomaceous earth powder is 800-1000 meshes.

4. A surfactant for washing fruits and vegetables according to claim 1, Features: The bactericidal preservative is one or more of nisin, natamycin, sodium benzoate and potassium sorbate, and the antibacterial substance is one or more of benzalkonium chloride and methylchloroisothiazolinone.

5. A surfactant for washing fruits and vegetables according to claim 1, Features: The enzyme preparation is one or more of protease, lipase and amylase.

6. A method for preparing a surfactant for washing fruits and vegetables, which is applicable to the surfactant for washing fruits and vegetables as claimed in any one of claims 1 to 3. Features: The preparation method of the surfactant for washing fruits and vegetables is as follows: Step S1: raw material preparation: diatomaceous earth is refined to obtain diatomaceous earth powder for later use; Step S2: preparing a modified surfactant: adding fatty alcohol polyvinyl ether, sodium cocoyl glutamate and medium-chain alkanol into a reaction kettle in sequence, and mixing them thoroughly to prepare a modified surfactant for later use; Step S3: Mixing preparation: uniformly mixing the modified surfactant obtained in step S2, the enzyme preparation, the cosolvent, the viscosity modifier, the bactericidal preservative, the light stabilizer, the antioxidant, the emulsifier, the antibacterial substance, the sodium citrate, the diatomaceous earth powder, the polyethylene glycol dispersant and the deionized water to prepare a viscous mixture; Step S4: Filtration and drying: The viscous mixture obtained in step S3 is filtered under reduced pressure to remove insoluble impurities therein, and then the filtered mixture is freeze-dried in a vacuum environment to obtain a fruit and vegetable cleaning surfactant, wherein the freeze-drying treatment temperature is -5 to -2°C and the treatment time is 20 minutes; Step S5: packaging and storage: packaging the prepared fruit and vegetable cleaning surfactant under sterile conditions; Step S6: Quality inspection: testing the pH value of the prepared fruit and vegetable cleaning surfactant and its pesticide residue removal effect in a low temperature environment.

7. A method for preparing a surfactant for washing fruits and vegetables according to claim 6, Features: The step S1 further includes the following steps: Step S11: Preliminary crushing: Put the large pieces of diatomaceous earth into a hammer crusher, and use a high-speed rotating hammer to hit and impact the large pieces of diatomaceous earth to form small pieces of diatomaceous earth, wherein the speed of the hammer is 35m / s and the operation time is 10-15min; Step S12: Grinding treatment: The small pieces of diatomaceous earth in step S11 are placed in a planetary ball mill and further ground into diatomaceous earth powder with a particle size of 800-1000 meshes.

8. The method for preparing a surfactant for washing fruits and vegetables according to claim 6, Features: The step S2 further includes the following steps: Step S21: Add fatty alcohol polyvinyl ether and medium-chain alkanol into a reaction kettle, and stir for 20-30 minutes at 30-40° C. to obtain a mixed solution; Step S22: Then add sodium cocoyl glutamate to the mixed solution prepared in step S21, continue stirring for 15-20 minutes, and compound to obtain a modified surfactant.

9. The method for preparing a surfactant for washing fruits and vegetables according to claim 6, Features: The step S3 further includes the following steps: Step S31: adding deionized water into the reaction kettle for preheating to a temperature of 55-65° C.; Step S32: adding the modified surfactant to the deionized water heated in step S31, stirring at a speed of 20-30 r / min for 5-10 min to mix evenly; Step S33: Cool the mixed reagent obtained in step S32, and when the temperature drops to 35° C., add enzyme preparation, cosolvent, bactericidal preservative, light stabilizer, antioxidant, emulsifier, antibacterial substance, diatomaceous earth powder and polyethylene glycol dispersant into the reaction kettle, stir at a speed of 30-40 r / min for 30 min under a constant temperature environment, and fully mix and dissolve to obtain solution A; Step S34: Then, sodium citrate is added to the solution A obtained in step S33, and stirring is continued for 10-15 minutes. Then, a viscosity regulator is added, and stirring is continued for 15-20 minutes at a speed of 45 r / min to obtain a viscous mixture.

10. The method for preparing a surfactant for washing fruits and vegetables according to claim 6, Features: The step S6 further includes the following steps: Step S61: Determine the pH value of the fruit and vegetable cleaning surfactant using the potentiometric method specified in GB / T6368, take 5 g of a fruit and vegetable cleaning surfactant sample at room temperature and place it in a clean measuring cup, immerse the calibrated pH meter electrode in the sample, gently stir the sample, and record the pH value after the pH meter reading stabilizes; Step S62: Under the environments of -10°C, -5°C, 0°C, 5°C and 20°C, the removal rate of residual pesticides is determined by the test method specified in GB / T24691-2022, and the removal effect of residual pesticides is comprehensively evaluated.

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