阅读说明：本技术 一种辣椒素微胶囊杀虫剂及其制备方法 (Capsaicin microcapsule pesticide and preparation method thereof ) 是由 陈宏伟 张小轩 吕海光 钱贞舟 冯晶 于 2021-08-10 设计创作，主要内容包括：本发明公开了一种辣椒素微胶囊杀虫剂及其制备方法,包括：以辣椒素为植物源农药的芯材；以及将芯材包覆,以明胶及CMC为原料的壁材；其中,所述壁材中含有小分子含氮化合物。所公开的植物源微胶囊杀虫剂不仅具有杀虫效果好,药效长的优点,而且其也兼有植物肥料的作用。(The invention discloses a capsaicin microcapsule pesticide and a preparation method thereof, wherein the preparation method comprises the following steps: capsaicin is taken as a core material of the botanical pesticide; and a wall material which coats the core material and takes gelatin and CMC as raw materials; wherein the wall material contains a small molecular nitrogen-containing compound. The plant source microcapsule pesticide has the advantages of good pesticidal effect and long pesticide effect, and also has the function of plant fertilizer.)

1. A capsaicin microencapsulated insecticide, comprising: capsaicin with an insecticidal effect is taken as a core material of the botanical pesticide;

and a wall material which coats the core material and takes gelatin and CMC as raw materials;

wherein the wall material contains a small molecular nitrogen-containing compound which can play a fertilizing role.

2. The capsaicin microcapsule insecticide according to claim 1, wherein the small molecule nitrogen-containing compound is one or more of urea or oxamide.

3. The capsaicin microcapsule pesticide according to claim 1, wherein the mass ratio of the core material to the wall material of the microcapsule is 1: 0.5-3.

4. The capsaicin microcapsule pesticide according to claim 1, wherein the mass ratio of the gelatin to the CMC is 7-11: 1.

5. The capsaicin microcapsule pesticide according to claim 1, wherein the small-molecule nitrogen-containing compound accounts for 5-10% by mass of the wall material.

6. A method for preparing a capsaicin microcapsule pesticide according to any one of claims 1 to 5, comprising the steps of:

extracting capsaicin from the capsicum by a supercritical fluid extraction method;

respectively adding a certain amount of gelatin and CMC (carboxy methyl cellulose) into distilled water to dissolve the gelatin and the CMC to form a gelatin solution and a CMC solution, and mixing the gelatin solution and the CMC solution to form a mixed solution;

adding the extracted capsaicin to the mixed solution and reacting to form a first emulsion;

coagulating the first emulsion to form a second emulsion by adjusting the pH to acidity and adjusting the stirring temperature and speed;

adding a small molecular nitrogen-containing compound into the second emulsion to form a third emulsion;

adjusting the pH of the third emulsion to be neutral and adding glutamine transaminase to solidify the third emulsion to form microcapsule dispersion liquid;

and (3) carrying out precipitation, washing and suction filtration on the microcapsule dispersion liquid to obtain a wet bag, and carrying out freeze drying on the wet bag to obtain the plant source microcapsule pesticide.

7. The method according to claim 6, wherein the mixed solution contains gelatin and CMC in a mass concentration of 0.5 to 2%, and the first emulsion is formed under a reaction condition of emulsifying in a tissue chopper at a rotation speed of 8000 to 12000r/min for 2 to 3 min.

8. The method according to claim 6, wherein the specific pH value for adjusting the pH to acidity in the second emulsion is 4.5 to 5, the solution used for adjusting the pH value is a 10% acetic acid solution, the stirring temperature is 35 to 50 ℃, and the stirring speed is 300 to 500 r/min.

9. The method of claim 6, wherein the temperature of the third emulsion is reduced to below 15 ℃ by an ice water bath before adjusting the pH.

10. The method according to claim 6, wherein the solution for adjusting pH to neutrality in the microcapsule dispersion is a 10% sodium hydroxide solution, the added transglutaminase is 0.5 to 1.5% by mass in the total reaction system, the stirring speed is maintained at 100 to 200r/min during the curing, and the curing time is 4 to 5 hours.

Technical Field

The invention relates to the field of biogenic pesticides, and particularly relates to a capsaicin microcapsule pesticide and a preparation method thereof.

Background

The use of chemical pesticides to promote the production and harvest of agricultural crops has been in the past hundred years and plays a role in human progress and social development. However, the negative effects of the traditional chemical pesticide are increasingly prominent while the traditional chemical pesticide plays a positive role in the aspects of agricultural yield increase, insect resistance, bacteriostasis and the like. Chemical pesticides are generally high in toxicity, pesticide residues are often caused after the chemical pesticides are used, and residual chemical substances can cause non-negligible influence on human health.

The plant-derived green pesticide is an active substance with insect-resisting and bacteriostatic effects prepared by extracting roots, stems, leaves, flowers, fruits, seeds and the like of plants or by utilizing secondary metabolites thereof. Compared with chemical pesticides, the capsaicine has the advantages of good environmental compatibility, capability of being decomposed into non-toxic substances in the nature, no enrichment, no pollution, safety to people and livestock, difficulty in generating drug resistance to diseases and pests, high safety and good selectivity, is the development direction of future pesticides, is a spicy component of capsicum, is an active component of capsicum, has excellent effects on expelling insects and killing insects, but has strong odor and irritation.

The microcapsule technology has the effects of improving physical properties of the coated substance, shielding taste and smell, and controlling the release of the substance. However, the core research of the current microcapsules is mainly the selection of the core material, the wall material of the microcapsules has no direct effect in the growth of crops, and the core material has single component and plays a single role in the growth process of plants. Therefore, the invention prepares the plant source microcapsule pesticide with multiple functions by changing the wall material.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a capsaicin microcapsule pesticide which has the insecticidal effect and can also provide a nitrogen fertilizer required by plant growth.

To achieve the above objects and other advantages and in accordance with the purpose of the invention, a first object of the present invention is to provide a capsaicin microcapsule insecticide, comprising: capsaicin is taken as a core material of the botanical pesticide;

and a wall material which coats the core material and takes gelatin and sodium carboxymethyl cellulose (CMC) as raw materials;

wherein the wall material contains a small molecular nitrogen-containing compound.

Preferably, the small-molecule nitrogen-containing compound is one or more of urea or oxamide.

Preferably, the mass ratio of the core material to the wall material of the microcapsule is 1: 0.5-3.

Preferably, the mass ratio of the gelatin to the CMC is 7-11: 1.

Preferably, the mass percentage of the small-molecule nitrogen-containing compound in the wall material is 5-10%.

In addition, another object of the present invention is to provide a method for preparing the plant-derived microencapsulated insecticide, which comprises:

extracting capsaicin from the capsicum by a supercritical fluid extraction method;

respectively adding a certain amount of gelatin and CMC (carboxy methyl cellulose) into distilled water to dissolve the gelatin and the CMC to form a gelatin solution and a CMC solution, and mixing the gelatin solution and the CMC solution to form a mixed solution;

adding the extracted capsaicin to the mixed solution and reacting to form a first emulsion;

coagulating the first emulsion to form a second emulsion by adjusting the pH to acidity and adjusting the stirring temperature and speed;

adding a small molecular nitrogen-containing compound into the second emulsion to form a third emulsion;

adjusting the pH of the third emulsion to be neutral and adding glutamine transaminase to solidify the third emulsion to form microcapsule dispersion liquid;

and (3) carrying out precipitation, washing and suction filtration on the microcapsule dispersion liquid to obtain a wet bag, and carrying out freeze drying on the wet bag to obtain the plant source microcapsule pesticide.

Preferably, the mass concentration of the gelatin and the CMC in the mixed solution is 0.5-2%, and the reaction condition for forming the first emulsion is emulsification in a tissue mincing machine at the rotating speed of 8000-12000 r/min for 2-3 min.

Preferably, the specific pH value for adjusting the pH value to acidity in the second emulsion is 4.5-5, the solution used for adjusting the pH value is a 10% acetic acid solution, the stirring temperature is 35-50 ℃, and the stirring speed is 300-500 r/min.

Preferably, the third emulsion is cooled to below 15 ℃ by an ice water bath before the pH is adjusted.

Preferably, the solution for adjusting the pH to be neutral in the microcapsule dispersion is a 10% sodium hydroxide solution, the mass percentage of the added glutamine transaminase in the total reaction system is 0.5-1.5%, the stirring speed of 100-200 r/min needs to be kept during curing, and the required curing time is 4-5 h.

Compared with the prior art, the invention has the beneficial effects that:

1. the plant source microcapsule pesticide is prepared by the microcapsule technology, the used materials are pure natural and pollution-free, and no chemical residue exists.

2. The invention takes capsaicin as a core material, is taken as an effective substance for killing insects, takes nitrogen-containing organic micromolecules as one of wall material selection materials, and is taken as a nitrogen fertilizer source, so that the prepared insecticide has double functions of killing insects and fertilizing, and the pesticide application frequency of a user is reduced.

3. The invention provides a microcapsule pesticide, which enables the insecticidal effective component capsaicin to be slowly released, reduces the dosage of the pesticide and enables the pesticide effect to be more durable.

Detailed Description

In order to understand the present invention, the following examples are given to further illustrate the present invention. The following description is only a preferred embodiment of the present invention, and is only for the purpose of describing the present invention, and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

S11: extracting capsaicin from the capsicum by a supercritical fluid extraction method;

supercritical fluid extraction techniques have been disclosed which combine some of the features of rectification and liquid-liquid extraction with cryogenic CO₂Is an extractant, effectively prevents the oxidation and the dissipation of heat-sensitive substances; in addition, it can increase boiling point and volatilityLow, easily pyrolysable substances are extracted below their boiling temperature; in addition, no organic solvent is used in the whole supercritical fluid extraction process, so that the extract has no residual solvent, and the harm to human body and environmental pollution in the extraction process are prevented.

S12, dissolving 14g of gelatin in 2800mL of distilled water to form a gelatin solution, dissolving 2g of CMC in 400mL of distilled water to form a CMC solution, and mixing the gelatin solution and the CMC solution to form a mixed solution;

s13, adding 32g of extracted capsaicin into the mixed solution, and completing an emulsion reaction in a tissue mincing machine at a rotating speed of 8000r/min to form a first emulsion, wherein the reaction time is 2 min;

and S14, forming a second emulsion by adjusting the pH of the first emulsion to 4.5 by using a 10% acetic acid solution and reacting for 40min under the condition that the stirring speed is 300r/min at 35 ℃.

S15: adding 0.8g of urea into the second emulsion to form a third emulsion under the condition of step S14;

and S16, cooling the third emulsion in an ice-water bath to 13 ℃, adjusting the pH to be neutral by using a 10% sodium hydroxide solution, adding glutamine transaminase into the third emulsion, wherein the mass percentage of the glutamine transaminase in the total reaction system is 0.5%, carrying out a curing reaction to form a microcapsule dispersion liquid, and curing for 4 hours at room temperature under the condition of a stirring speed of 100 r/min.

S17: and (3) carrying out precipitation, washing and suction filtration on the microcapsule dispersion liquid to obtain a wet bag, and carrying out freeze drying on the wet bag to obtain the plant source microcapsule pesticide.

The invention adopts the capsaicin as the core material, has the insecticidal effect, particularly has excellent treatment effect on the aspects of treating the cabbage aphids and cabbage caterpillars, and simultaneously has the advantages of no pollution and no residue as the purely natural botanical pesticide.

The invention utilizes the microcapsule technology to prepare the pesticide, takes the plant-derived pesticide as the core material and takes the gelatin and the CMC as the wall materials, so that the plant-derived pesticide in the pesticide is slowly released, the using amount of the pesticide is reduced, and the effective insecticidal time of the pesticide is prolonged. In addition, the microcapsule pesticide prepared by the complex coacervation method has the advantages of simple operation and mild conditions.

The wall material is selected from gelatin and CMC, is a natural material, and has the advantages of no pollution and no environmental burden. Meanwhile, the nitrogen-containing micromolecules are added into the wall materials, so that the microcapsule pesticide has the function of a nitrogen fertilizer, the fertilization times of a user are reduced, and the plant planting process of the user is optimized.

Example 2

S21: extracting capsaicin from the capsicum by a supercritical fluid extraction method;

s22, dissolving 20g of gelatin in 2000mL of distilled water to form a gelatin solution, dissolving 2g of CMC in 200mL of distilled water to form a CMC solution, and mixing the gelatin solution and the CMC solution to form a mixed solution;

s23, adding 22g of extracted capsaicin into the mixed solution, and completing an emulsion reaction in a tissue mincing machine at a rotating speed of 10000r/min to form first emulsion, wherein the reaction time is 2.5 min;

s24, forming a second emulsion by adjusting the pH of the first emulsion to 4.7 with 10% acetic acid solution and reacting for 40min at 45 ℃ with a stirring speed of 400 r/min.

S25: under the condition of step S24, adding 1.54g of urea into the second emulsion to form a third emulsion;

and S26, cooling the third emulsion in an ice-water bath to 15 ℃, adjusting the pH to be neutral by using a 10% sodium hydroxide solution, adding glutamine transaminase to the third emulsion, wherein the mass percentage of the glutamine transaminase in the total reaction system is 1%, carrying out a curing reaction to form a microcapsule dispersion liquid, and curing for 5 hours at room temperature under the condition of stirring at 140 r/min.

S27: and (3) carrying out precipitation, washing and suction filtration on the microcapsule dispersion liquid to obtain a wet bag, and carrying out freeze drying on the wet bag to obtain the plant source microcapsule pesticide.

Example 3

S31: extracting capsaicin from the capsicum by a supercritical fluid extraction method;

s32, dissolving 22g of gelatin in 1100mL of distilled water to form a gelatin solution, dissolving 2g of CMC in 100mL of distilled water to form a CMC solution, and mixing the gelatin solution and the CMC solution to form a mixed solution;

s33, adding 32g of extracted capsaicin into the mixed solution, and completing an emulsification reaction in a tissue mincing machine at a rotating speed of 8000r/min to form first emulsion;

s34, forming a second emulsion by adjusting the pH of the first emulsion to 5 with 10% acetic acid solution and reacting for 40min at 50 ℃ with a stirring speed of 500 r/min.

S35: adding 2.4g of oxamide to the second emulsion under the conditions of step S34 to form a third emulsion;

and S36, cooling the third emulsion in an ice-water bath to 14 ℃, adjusting the pH to be neutral by using a 10% sodium hydroxide solution, adding glutamine transaminase into the third emulsion, wherein the mass percentage of the glutamine transaminase in the total reaction system is 1.5%, carrying out a curing reaction to form a microcapsule dispersion liquid, and curing the microcapsule dispersion liquid at room temperature for 5 hours under the condition of a stirring speed of 200 r/min.

S37: and (3) carrying out precipitation, washing and suction filtration on the microcapsule dispersion liquid to obtain a wet bag, and carrying out freeze drying on the wet bag to obtain the plant source microcapsule pesticide.

And (3) testing the insect killing and expelling effect:

the insect killing and expelling effect is characterized by applying a certain amount of insecticide in a plant with diseases and insect pests, the quality of the applied insecticide is determined by controlling the quality of capsaicin to be equal, the number of dead insects at 7 days and 30 days is tested, and the plant growth condition at 30 days is also tested.

The death rate (%) < dead insect number/total insect number x 100%

Comparative example 1 is no pesticide application and comparative example 2 is a conventional plant-derived pesticide capsaicin applied in an amount equal to the mass of capsaicin applied in the examples.

As can be seen from Table 1: compared with comparative example 1, the examples have better insecticidal effect, compared with comparative example 2, the examples have stronger insecticidal timeliness, and still have good insecticidal effect at 30 days. In comparison with comparative examples 1 and 2, the plants to which the example insecticides were applied exhibited a significantly higher growth potential than the comparative examples in 30 days.

The insecticidal experiments prove that the microcapsule insecticide has a good insecticidal effect and has the advantage of long time, and in addition, the microcapsule insecticide contains a nitrogen fertilizer required by plants and also has a promoting effect on the growth of the plants.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.