CN116285508A - Film forming agent for apple bagging-free, and preparation method and application thereof - Google Patents

Abstract

The invention relates to a film forming agent for apple bagging-free, a preparation method and application thereof, wherein the film forming agent comprises chitosan lactate, 6-amino cellulose lactate, glycine and calcium glycinate, wherein the total mass of the chitosan lactate and the 6-amino cellulose lactate accounts for 0.5-3.5% of the total mass of the film forming agent, the mass of the calcium glycinate accounts for 5-15% of the total mass of the film forming agent, the mass of the glycine accounts for 5-15% of the total mass of the film forming agent, and the balance is water. The film forming agent containing chitosan lactate, 6-amino cellulose lactate, calcium glycinate and glycine can obviously improve the control effect on apple diseases on the premise of not carrying out bagging operation on apples, so that the incidence rate of the apple diseases is reduced, and meanwhile, the quality of apple fruits can be improved.

Description

Film forming agent for apple bagging-free, and preparation method and application thereof

Technical Field

The invention belongs to the field of agricultural medicaments, in particular to agricultural plant protection and agricultural management chemicals, and particularly relates to a film forming agent for bagging-free apples, and a preparation method and application thereof.

Background

The China is a large country for planting apples, 25 provinces of apples are planted in the country, the planting area exceeds 3000 mu, and the yield exceeds 4000 ten thousand tons. In the growing period of apples, the anthracnose, ring spot and rust of the apples are one of the frequently occurring diseases, and in order to prevent and treat the diseases and insect pests of the apples and improve the quality of the fruits, fruit farmers also use bagging operation to achieve the effects of protecting the surfaces of the apples from being polluted by pesticides, improving the quality of the fruits and the like, but the traditional bagging operation not only can reduce the taste of the apples, but also can increase the labor cost of the bagging and the safety risk in the bagging process, and the traditional bagging operation can not effectively prevent and treat the infection of the apples caused by the diseases, so that a novel method and a product which can effectively prevent and treat the diseases of the apples and can save the bagging step are developed, the planting cost of the apples is lower, and especially the labor cost can be greatly reduced, and the safety risk of the bagging of the apples can be reduced.

Chitosan is becoming more and more interesting as a novel nontoxic natural fruit and vegetable preservative. It can not only form semi-permeable membrane on the surface of fruit, but also effectively inhibit invasion and growth of pathogenic bacteria, but also can be used for fresh-keeping of isolated fruit and vegetable to prolong fresh-keeping period. However, there are few studies and reports on the application to living crops to improve the quality of crops or fruits, and there are also some studies on the use of chitosan single component or combination with other film forming components to improve the quality of crops protection, but there is no study on the application of apple bagging-free, and the applicant studies of the present application find that the effect of chitosan alone is not obvious.

6-amino cellulose (or referred to as 6-amino-6-deoxycellulose) is also a film-forming substance which, when used alone, is cost-prohibitive and, although capable of forming films, is generally used for film formation on industrial surfaces. The production of 6-amino cellulose is generally carried out by preparing sodium cellulose sulfate and ammonia water under high temperature and high pressure, for example, the method disclosed in patent CN107597076A has a relatively large number of film forming substances of amino cellulose in the market, wherein the 6-amino cellulose has similar properties as chitosan because of containing amino groups, and has relatively good compatibility with chitosan.

The invention develops a film forming agent special for apple bagging-free through research, and can solve the problem of apple bagging-free.

Disclosure of Invention

In order to solve the technical problems, the invention provides a film forming agent for apple bagging-free, which comprises chitosan lactate, 6-amino cellulose lactate, glycine and calcium glycinate, wherein the total mass of the chitosan lactate and the 6-amino cellulose lactate accounts for 0.5-3.5% of the total mass of the film forming agent, the calcium glycinate accounts for 5-15% of the total mass of the film forming agent, the glycine accounts for 5-15% of the total mass of the film forming agent, and the balance is water.

Preferably, in the film forming agent, the mass ratio of the chitosan lactate to the 6-amino cellulose lactate is 1:0.1-10, preferably, the mass ratio of the chitosan lactate to the 6-amino cellulose lactate is 1:0.2-5.0, and particularly preferably, the mass ratio of the chitosan lactate to the 6-amino cellulose lactate is 1:0.8-1.2.

Preferably, in the film forming agent, the total mass of the chitosan lactate and the 6-amino cellulose lactate accounts for 3.0-3.5% of the total mass of the film forming agent.

Preferably, in the film forming agent, the chitosan lactate and the 6-amino cellulose lactate are prepared from chitosan, 6-amino cellulose, lactic acid and solvent water, wherein the solvent water is water for dissolving calcium glycinate, water for dissolving glycine and water for dissolving lactic acid.

Preferably, in the film forming agent, the chitosan lactate refers to the salt formation of glucosamine units and lactic acid in chitosan, and the 6-amino cellulose lactate refers to the salt formation of chitosan 6-glucosamine units and lactic acid.

Preferably, in the film forming agent, in the raw materials for preparing the film forming agent, the mass ratio of the chitosan to the 6-amino cellulose is 1:0.1-10, preferably, the mass ratio of the chitosan to the 6-amino cellulose is 1:0.2-5.0, and the mass ratio of the chitosan to the 6-amino cellulose is 1:0.8-1.2.

Preferably, in the film forming agent, the percentage of lactic acid mass in the raw material for preparing the film forming agent is 40-60% of the sum of chitosan and 6-amino cellulose mass, and preferably, the percentage of lactic acid mass in the sum of chitosan and 6-amino cellulose mass is 50-55%.

Preferably, in the film forming agent, the preparation method of the film forming agent comprises the following steps:

step 1: and dissolving calcium glycinate in water to prepare a calcium glycinate aqueous solution.

Step 2: dissolving glycine in water to prepare glycine aqueous solution.

Step 3: mixing chitosan and 6-amino cellulose, and then sufficiently grinding and crushing to prepare a powder mixture of chitosan and 6-amino cellulose.

Step 4: and fully mixing the powder mixture of chitosan and 6-amino cellulose with the calcium glycinate aqueous solution and the glycine aqueous solution to obtain a solid-liquid mixture.

Step 5: and (3) mixing lactic acid and water to prepare a lactic acid aqueous solution, slowly adding the solid-liquid mixture obtained in the step (4) into the lactic acid aqueous solution under the condition of stirring, and fully stirring to obtain a transparent solution, namely the film forming agent.

Preferably, in the film forming agent, the temperature of each solution is kept at 40-80 ℃, preferably, the temperature of each solution is kept at 50-70 ℃, and particularly preferably, the temperature of each solution is kept at about 60 ℃, namely, 60+/-2 ℃.

Preferably, in the film forming agent, the average molecular weight of the chitosan is 100-300kDa, and the deacetylation degree of the chitosan is more than 90%.

Preferably, in the film forming agent, the deacetylation degree of the chitosan is 90-98%.

Compared with the film forming agent prepared from monocomponent chitosan or the film forming agent prepared from monocomponent 6-amino cellulose, the film forming agent disclosed by the invention has more excellent rain wash resistance, the film dried by the film forming agent has stronger toughness, the film can not break along with the growth of fruits, the bagging-free effect is better realized, and the mixed film forming agent has excellent effects in preventing and treating anthracnose, ring spot and/or rust of fruits of apples.

The invention also provides application of the film forming agent in bagging of apples, which is characterized in that the film forming agent is applied to spray apples to replace the bagging of apples, so that the quality of apples is realized and is higher than that of apples in bagging of apples, and anthracnose, ring spot and/or rust of apples are reduced.

Preferably, in the application, the film forming agent is applied to spray apple fruits to replace apple fruit bagging, so that the quality of the apple fruits is realized and is higher than that of the apple fruits in the process of bagging, and the anthracnose, ring spot and rust of the apple fruits are reduced.

Preferably, in the above application, the apple fruit quality is one or more of single fruit weight, fruit firmness, soluble solids, solid to acid ratio, peel firmness, peel ductility, pulp firmness and pulp crispness.

Preferably, in the application of the film forming agent in the apple bagging-free application, the starting time of spraying the film forming agent is half a month after apple fruit thinning when the apple bagging period begins, or the film forming agent is sprayed about half a month after fruit setting, and the weather of spraying the film forming agent is preferably sunny, if the film forming agent is not required to be sprayed in rainy days, if rainfall is required to be performed within 12 hours after spraying, the film forming agent is preferably sprayed again.

Preferably, in the application of the film forming agent in the bagging-free application of apples, the spraying object of the film forming agent is mainly apple fruits, and the spraying degree is that the apple fruits are fully soaked by the film forming agent. The apple leaf surface can be sprayed at the same time of spraying, the degree of the sprayed film forming agent on the apple leaf surface is not limited, and the excessive spraying has a promoting effect on the growth of apples, especially the growth of young leaves.

Preferably, in the application of the film forming agent in apple bagging-free, the concentration of the sum of the mass of chitosan lactate and 6-amino cellulose lactate in an aqueous solution is 50-500mg/L, preferably the concentration of the sum of the mass of chitosan lactate and 6-amino cellulose lactate in an aqueous solution is 200-400mg/L when apple is sprayed by the film forming agent.

The above and the following description of the apple bagging-free means that the apple fruits are not physically sealed by adopting a mode of bagging, bagging paper bags, paper clip bags or the like, because the bagging is basically to wrap the apple fruits by plastic films or paper sheets or the like, the bag formed by the plastic films or the bag formed by the paper sheets or the bag formed by combining the paper sheets and the plastic films is required to be manually sleeved on the apple fruits, and the step can be completed by manual operation. Along with the popularization of the bagging, various defects of the bagging are gradually developed, such as higher labor cost of the bagging, direct sunlight received by apples after bagging is reduced, oxygen and carbon dioxide exchange of fruits is blocked, a reflective film is paved under the fruit trees in a coloring period to supplement illumination for the apples so as to improve the coloring degree, and for higher apple trees, the apple bagging at the top of the tree has great danger, and the situation that personnel fall hurt in the bagging process often occurs.

The film forming agent solves the problem that the fruit surfaces of apples are protected by applying the film forming agent without bagging, but the bagging effect can be achieved, and even the bagging effect is better in certain aspects. The film forming agent provided by the invention realizes high light transmittance after film formation on fruit surfaces, improves fruit quality, and prevents and treats a plurality of diseases of apple fruits.

The invention also provides application of the film forming agent in preventing and treating anthracnose, ring spot and/or rust of apples and improving the quality of apples.

Preferably, the invention provides application of the film forming agent in preventing and treating anthracnose, ring spot and rust of apples and improving the quality of apples.

The film forming agent can be used for solving the bagging-free problem of apples, can prevent diseases on apple fruits, and can prevent anthracnose, ring spot and/or rust of apple fruits by spraying the film forming agent on apple fruits under the condition of not bagging, so that the smoothness of the surfaces of the fruits can be improved, and the content of beneficial nutritional ingredients of the fruits can be improved.

Preferably, for the above-mentioned use, the apple fruit quality is one or more of single fruit weight, fruit firmness, soluble solids, solid-to-acid ratio, peel firmness, peel ductility, pulp firmness and pulp crispness.

For the above-described improvement in fruit quality, it is possible for the consumer to be a reduction in fruit quality in some aspects, but the consumer still recognizes that the fruit quality is improved as a whole. For example, an increase in single fruit weight results in an increase in yield, while an increase in fruit hardness may increase, which may facilitate stacking during storage and transport without breakage, both of which are better than the no-bag set and the bagging set, and an increase in soluble solids and acid ratio may also be superior to the no-bag set and the bagging set, and so on.

The invention also provides a method for preventing and treating anthracnose, ring spot and/or rust of apples and bagging-free apples by applying the film forming agent, which comprises the following steps: and (3) when the bagging period of the apples starts, the film forming agent is diluted and then sprayed on the surfaces of the apples, the diluted concentration of the film forming agent is 50-500mg/L in terms of the concentration of the sum of the masses of chitosan and 6-amino cellulose in an aqueous solution, the application times are 2-7 times, the interval of each application is 10-30 days, preferably, the diluted concentration of the film forming agent is 200-500mg/L in terms of the concentration of the sum of the masses of chitosan and 6-amino cellulose in the aqueous solution, the application times are 3-5 times, and the interval of each application is 15-25 days.

In the above method, the time and environmental conditions of the bagging can be specifically referred to the above description.

The invention also provides a method for preparing the film forming agent, which comprises the following steps:

step 1: dissolving calcium glycinate in water to prepare calcium glycinate water solution;

step 2: dissolving glycine in water to prepare glycine aqueous solution;

step 3: mixing chitosan and 6-amino cellulose, and then fully grinding and crushing to prepare a powder mixture of the chitosan and the 6-amino cellulose;

step 4: fully mixing a powder mixture of chitosan and 6-amino cellulose with a calcium glycinate aqueous solution and a glycine aqueous solution to obtain a solid-liquid mixture;

step 5: and (3) mixing lactic acid and water to prepare a lactic acid aqueous solution, slowly adding the solid-liquid mixture obtained in the step (4) into the lactic acid aqueous solution under the condition of stirring, and fully stirring to obtain a transparent solution, namely the film forming agent.

In the method for preparing the film forming agent, under the condition that the total mass concentration of chitosan and 6-glucosamine in the film forming agent is up to 3-4%, the solution can be stirred, bottled and poured, and meanwhile, calcium glycinate in the solution can be completely dissolved. The film forming agent prepared by the method is sprayed on apple surfaces and dried to form films under the action of chitosan lactate and 6-amino cellulose lactate, and the films have high toughness and high rain wash resistance, so that mottled falling of film layers caused by infiltration of rain water, liquid medicine and dew is avoided.

In the method, the dissolution process can be carried out without water bath heating, but the dissolution time is long, so the materials and the reaction mixture are preferably heated in the preparation process, the salt forming process of chitosan and 6-amino cellulose can be accelerated by heating, the viscosity of the film forming agent in the salt forming process can be reduced, and the stirring is more facilitated. The calcium glycinate and the glycine are dissolved into aqueous solution in the preparation process, and the aqueous solution is used as a reaction solvent for reaction, so that the calcium glycinate and the glycine fully permeate into chitosan lactate and 6-amino cellulose lactate, the slow release effect is achieved in the film drying stage after bagging-free drug application, and the calcium glycinate and the glycine are slowly released and absorbed by apple fruits along with slow degradation of the film, so that the quality of the apple fruits is improved, and the disease resistance effect of the apple fruits is improved.

The beneficial effects of the invention are that

After the film forming agent containing chitosan lactate, 6-amino cellulose lactate, glycine and calcium glycinate is applied to apple fruits, the control effect of anthracnose, ring spot and rust of the apple fruits can be obviously improved under the condition that bagging operation is not required for the apples, so that the incidence rate of the anthracnose, ring spot and rust of the apple fruits is further reduced, and meanwhile, the quality of the apple fruits, such as single fruit weight, fruit hardness, soluble solids, solid-acid ratio, peel hardness, peel ductility, pulp hardness, pulp brittleness and the like, is improved.

The film forming agent disclosed by the invention contains two salts, so that the performance of the film forming agent is improved, and the film forming agent can not only not influence the growth of apple fruits, but also promote the quality improvement of the apple fruits and prevent the diseases of the apple fruits when being applied to the surfaces of the apple fruits. The mixed polymer of chitosan lactate and 6-amino cellulose has better film forming property, better ductility and stronger rain wash resistance, and the film is automatically stretched along with the growth of fruits, and the film forming agent is sprayed again to form a film again under the condition that the film cannot be stretched. Compared with the film forming agent in the current market, the film forming agent has more excellent performance and is more suitable for being used as a substitute product of the apple fruit bagging-free.

The effect of glycine and calcium glycinate is not only to promote the growth of apple fruits and regulate the color of apple fruits, but also to help the strength improvement of the film, the toughness improvement of the film and the increase of the thickness of the film.

The film forming agent can be directly diluted and sprayed on apple surfaces, although the film forming agent is used, the viscosity of the diluted liquid does not influence the spraying effect of a spraying device, the spraying is uniform, and the film forming agent can be sprayed on the tops of apple trees and apple fruits on the tops of the apple trees by the spraying device which normally sprays the film forming agent on the tops of the apple trees, so that the apple fruits which cannot be covered by bags on the tops of the trees can be free from the risk of bag covering by spraying the film forming agent, the effect which can be achieved by bag covering is solved, and even the effect which can be achieved by bag covering is achieved by bag covering.

After the film forming agent disclosed by the invention is sprayed on apple surfaces, transparent films can be formed on the apple surfaces within 24 hours after the surfaces of the apple fruits are fully wetted, the transparent films are invisible to naked eyes, but the existence of the films can be perceived through rubbing, so that the photosynthesis and respiration of the apple fruits are not affected by the existence of the films.

Detailed Description

The raw materials used in the following examples were all supplied from Agents Inc. of Agents, gao Ke Co., ltd. In the Hainan industry.

1. Preparation of film Forming agent

Among the raw materials used in the following examples, chitosan was white powder having a molecular weight of 10 to 30 ten thousand, a degree of deacetylation of 92%, a water content of 9%, and was insoluble in water.

Example 1: preparation of film Forming agent

Step 1: 100g of calcium glycinate was dissolved in 150g of water, and then heated to 60℃and maintained at that temperature to prepare an aqueous calcium glycinate solution for use.

Step 2: 100g of glycine was dissolved in 400g of water, and then heated to 60℃and maintained at that temperature to prepare an aqueous glycine solution for use.

Step 3: mixing 12g of chitosan and 11g of 6-amino cellulose, and then sufficiently grinding and crushing to prepare a powder mixture of the chitosan and the 6-amino cellulose for later use.

Step 4: fully stirring the powder mixture of chitosan and 6-amino cellulose, the calcium glycinate aqueous solution and the glycine aqueous solution, and maintaining the temperature at 60 ℃ to obtain a solid-liquid mixture for later use.

Step 5: 13g of lactic acid is added into a 2L reaction vessel, 200g of water is added, stirring is fully carried out, when the lactic acid is completely dissolved, a transparent solution is obtained, a lactic acid aqueous solution is obtained, then the lactic acid aqueous solution is heated to 60 ℃ in a water bath, the temperature in the reactor is maintained at 60 ℃, the solid-liquid mixture in the step 4 is slowly added under the stirring condition, stirring is fully carried out for 10 minutes after the addition is finished, a transparent solution is obtained, then water is supplemented to 1000g, stirring and cooling are fully carried out, and 1000g of bagging-free film forming agent is obtained.

Example 2: preparation of contrast film Forming Agents

According to the method of example 1, a chitosan film forming agent was prepared by changing the raw materials of 12g of chitosan and 11g of 6-amino cellulose into 24g of chitosan, and an amino cellulose film forming agent was prepared by changing the raw materials of 12g of chitosan and 11g of 6-amino cellulose into 22g of 6-amino cellulose.

Example 3: film release effect test of film Forming agent

Because the film forming agent is mainly applied to the fruit of the reserved tree, compared with the fruit which is picked up, the film forming agent of the fruit of the reserved tree has different fresh keeping, and the film forming agent must withstand the damage of wind, sunlight and water, and the screening of the film forming agent is mainly based on the test of demoulding after water immersion. Demolding after water immersion is a main index, and because the tree fruit is easy to be subjected to dew, spraying of liquid medicine, infiltration of rainwater and scouring, the demolding effect of the film forming agent is tested by a water immersion mode.

The specific test method comprises the following steps: the film forming agents of example 1 and example 2 were diluted 100 times to obtain a diluted solution, then apples (fresh apples, ensuring no wax layer and other surface treatments) were completely immersed in the diluted solution, the apples were taken out after immersion and air-dried for 24 hours, then the air-dried apples were soaked in clear water for 1 minute, then drained, the maximum diameter positions of the apples were touched by hand without dripping, if there was a sticky feel on the surface of the peel, the air-dried apples were completely immersed in clear water for 1 minute after air-drying again for 24 hours, and the film forming agents with the longest number of film removing times were determined in this way, and each film forming agent was used for 5 fresh apples.

The results obtained by the above test methods were: firstly, the treatment without sticky feeling is that an amino cellulose film forming agent is adopted, and after the water is added for 2.4 times on average, the surface of the apple has no sticky feeling, namely, the apple is demoulded after 2.4 times; the next step is chitosan film forming agent, the average 3.4 times, the most times of film stripping are the bagging-free film forming agent of the embodiment 1, and the average 5.6 times of film stripping after soaking, so the bagging-free film forming agent is used as a bagging-free field bagging-free test agent, and the film forming agent used in the following embodiment 4 is the film forming agent prepared in the embodiment 1.

Example 4: film forming agent apple bagging-free function determination

(1) Experimental protocol

And selecting an apple garden with uniform altitude topography from Qian county apple demonstration gardens, and controlling the conditions of fertilizer application amount, water watering amount and the like to be consistent. Three treatments were set up, the treatment agents and treatment methods are shown in Table 1 below, each treatment was sprayed in one row (9-11 apple trees), and safety belts were set up between treatments. Marking before the first application (the start time of bagging of apples is conventionally managed, young fruits are table tennis in size), fixing a branch in five directions of east, west, south, north and middle of each tree, investigating and counting the surface finish degree of all fruits on the branch before each application, and measuring the related data of fruit quality after the last application.

Table 1 exemplary apple garden test protocol

Test cell	Medicament or tool	Dilution factor	Number of times of application	Days of interval
					Film former treatment group	Example 1 film Forming agent	100 times of	5 times	About 30 days
Bagging set	Plastic film bag	-	-	-
					Bag-free group	Water and its preparation method	-	-	-

In table 1 above, the no-bag group was managed as normal. The bagging group is a normal bagging, the bag is a plastic film bag, the bagging group sprays clear water when the film forming agent treatment group sprays the film forming agent, the bagging group takes off the bag after the fruits are ripe, a reflective film is paved under the tree according to the conventional treatment, and the apple fruits are normally colored by illumination. Apples of the film forming agent treatment group are normally managed, namely insect prevention and disease prevention are normally performed, but unlike the bagging group, the film forming agent treatment group does not perform reflective film paving when the bagging group performs reflective film treatment. The optimal mode of the film forming agent treatment group during the application treatment is to spray the fruits, the spraying to the leaves is free from problems, the maximum effect is exerted, the fruits are sprayed thoroughly, the apples are fully soaked, and the spraying of the film forming agent can be stopped when the drops of the film forming agent aqueous solution drop at the bottom of the fruits.

(2) Measurement index

And in the picking period of the apples, measuring the apples according to the apples at the determined positions in the test scheme, and collecting the following data:

(1) fruit anthracnose, fruit ring spot and fruit rust.

(2) The longitudinal and transverse diameter of the fruits, the weight of single fruits, soluble solids and titratable acid.

(3) And (5) respectively finding points at four positions in the middle of the fruit by using a fruit sclerometer to measure the peeling hardness.

(4) The fruit is measured by a texture analyzer for 2 sides of the fruit, and 5 indexes including peel hardness, peel ductility, pulp hardness, pulp brittleness and pulp compactness are measured.

(5) The fruit surface color difference was measured with a color difference meter, 6 times per fruit.

(3) Measurement results

The effects of fruit anthracnose, fruit ring rot, and fruit rust incidence in the different treatment groups are shown in table 2 below. As can be seen from Table 2, the occurrence rate of anthracnose, ring spot and fruit rust of the film forming agent treatment group is reduced by 24.07%, 23.75% and 5.92% respectively compared with the bagging group; reduced by 49.38%, 61.15%, 35.18%, respectively, compared to the no-bag set.

TABLE 2 occurrence of fruit diseases in each treatment group

Test cell	Incidence of fruit anthracnose	Incidence of fruit ring rot	Incidence of fruit rust
				Film former treatment group	0.41％	0.61％	16.36％
Bagging set	0.54％	0.80％	17.39％
				Bag-free group	0.81％	1.57％	25.24％

The results of the single fruit weight, hardness, soluble solids, and solid acid ratio of the apple fruits of each test group are shown in the following table 3, and as can be seen from table 3, the single fruit weight, hardness, soluble solids, and solid acid ratio of the film forming agent treatment group are obviously increased compared with the control group. From the results, the film forming agent treatment group is increased by 6.05% compared with the bagging group and 10.37% compared with the non-bagging group in the aspect of influencing the single fruit weight of the fruits; in the aspect of influence on the hardness of fruits, the film forming agent treatment group is increased by 12.86% compared with the bagging group and is increased by 5.33% compared with the non-bagging group; in the aspect of influencing the soluble solids of fruits, the film forming agent treatment group is increased by 11.64 percent compared with the bagging group and is increased by 11.09 percent compared with the non-bagging group; in terms of the effect on the fruit acid-fixing ratio, the film forming agent treatment group is increased by 15.09% compared with the bagging group and is increased by 24.49% compared with the non-bagging group.

Table 3 results of individual fruit weights, hardness, soluble solids, and solids to acid ratios of the treated apples

As can be seen from table 4 below, the results of the apple fruit surface color differences for each treatment group were found to be not significantly different from each other in the fruit surface color difference correlation data L (from black to white, 0 to 100), a (from green to red, -a to +a), and b (from blue to yellow, -b to +b) between the treatments. This shows that the color of the fruit surface is not different from that of the reflective film of the bagging set by the film forming agent, and the film formed by the film forming agent on the fruit surface in the film forming agent treatment process can not prevent the fruit from absorbing sunlight, but also has the effect of promoting color conversion.

Table 4 results of detection of apple surface color differences for each treatment group

Test cell	L	a	b
				Film former treatment group	47.68	20.66	19.28
Bagging set	51.78	22.13	21.92
				Bag-free group	46.98	19.69	18.65

As can be seen from table 5 below, the results of peel hardness, peel ductility, pulp hardness, and pulp crispness of the apples of each treatment group are shown in table 5 below, and in terms of peel hardness, the film former treatment group is improved by 18.17% and 12.74% compared with the bagging group and the non-bagging group, respectively; in the aspect of peel ductility, the film forming agent treatment group is respectively improved by 31.57 percent and 1.71 percent compared with the bagging group and the non-bagging group; in terms of pulp hardness, the film forming agent treatment group is respectively improved by 5.32 percent and 16.00 percent compared with the bagging group and the non-bagging group; there was no significant difference between the film former treated group and the two groups in terms of pulp brittleness.

TABLE 5 influence of film Forming Agents on apple peel hardness, peel ductility, pulp hardness, pulp crispness

The film forming agent of the embodiment 1 has certain promotion effects on reducing fruit diseases and improving various quality of fruits after being used, and is superior to the traditional bagging technology.

Claims (8)

1. The film forming agent for the apple bagging-free is characterized by comprising chitosan lactate, 6-amino cellulose lactate, glycine and calcium glycinate, wherein the total mass of the chitosan lactate and the 6-amino cellulose lactate accounts for 0.5-3.5% of the total mass of the film forming agent, the calcium glycinate accounts for 5-15% of the total mass of the film forming agent, the glycine accounts for 5-15% of the total mass of the film forming agent, and the balance is water.

2. Film former according to claim 1, characterized in that the mass ratio of chitosan lactate to 6-amino cellulose lactate is 1:0.1-10.

3. Film former according to claim 2, characterized in that the chitosan lactate and 6-amino cellulose lactate are prepared from chitosan, 6-amino cellulose, lactic acid and solvent water.

4. A film former according to claim 3, characterised in that the lactic acid mass is 40-60% of the sum of chitosan and 6-amino cellulose mass.

5. Use of the film forming agent according to any one of claims 1 to 4 for bagging apples, characterized in that the film forming agent according to any one of claims 1 to 4 is applied to spray apple fruits to replace the bagging of apple fruits, so that the quality of apple fruits is achieved and is higher than that of apple fruits when the apple fruits are bagged, and the anthracnose, ring spot and rust of the fruits of apples are reduced.

6. The use according to claim 5, characterized in that the apple fruit quality is one or more of single fruit weight, fruit firmness, soluble solids, solids to acid ratio, peel firmness, peel ductility, pulp firmness and pulp crispness.

7. A method for preventing and treating anthracnose, ring spot and rust of apples by using the film forming agent as claimed in any one of claims 1 to 4, and realizing bagging-free apples, which comprises the following steps: and (3) when the bagging period of the apples starts, the film forming agent is diluted and then sprayed on the surfaces of the apples, the diluted concentration of the film forming agent is 50-500mg/L in terms of the concentration of the sum of the mass of chitosan and the mass of 6-amino cellulose in an aqueous solution, the application times are 2-7 times, and the interval of each application is 10-30 days.

8. A method of preparing a film former, the method comprising the steps of:

step 1: dissolving calcium glycinate in water to prepare calcium glycinate water solution;

step 2: dissolving glycine in water to prepare glycine aqueous solution;

step 3: mixing chitosan and 6-amino cellulose, and then fully grinding and crushing to prepare a powder mixture of the chitosan and the 6-amino cellulose;

step 4: fully mixing a powder mixture of chitosan and 6-amino cellulose with a calcium glycinate aqueous solution and a glycine aqueous solution to obtain a solid-liquid mixture;

step 5: and (3) mixing lactic acid and water to prepare a lactic acid aqueous solution, slowly adding the solid-liquid mixture obtained in the step (4) into the lactic acid aqueous solution under the condition of stirring, and fully stirring to obtain a transparent solution, namely the film forming agent.