WO2021088188A1

WO2021088188A1 - Citrus reticulata preservative containing hermetia illucens-sourced chitosan

Info

Publication number: WO2021088188A1
Application number: PCT/CN2019/123903
Authority: WO
Inventors: 徐齐云; 曾鑫年
Original assignee: 华南农业大学
Priority date: 2019-11-08
Filing date: 2019-12-09
Publication date: 2021-05-14
Also published as: CN111296558A

Abstract

A citrus reticulata preservative or a Penicillium italicum inhibitor, containing Hermetia illucens-sourced chitosan and fludioxonil with a mass ratio of (49-1):1.

Description

Sugar orange antistaling agent containing chitosan from black shui flies

Technical field

The invention belongs to the field of sugar orange preservation, and in particular relates to a sugar orange preservation agent containing chitosan derived from black flies.

Background technique

Shatang orange, also known as October orange, is an excellent variety of oranges and one of the four great fruits in Lingnan. In the past ten years, the most profitable variety of Guangdong fruits is Shatangju. In recent years, the Guangdong Provincial Government has taken a series of practical measures to make the Shatang orange industry develop by leaps and bounds. The Shatang orange plantation area has reached 3 million mu, and the output has jumped to the main citrus-producing provinces (regions) in the country. The first one.

Shatangju fruit is oblate, orange-yellow in color, juicy and sweet, with a sugar content of 15%-18%, crisp and tender and slag, excellent flavor, thin skin, easy to peel and not wet hands. However, due to the crisp and tender skin, juiciness and high sugar content of Shatang Tangerine, it is extremely vulnerable to mechanical damage and microbial infection, and its storage period is relatively short compared with other citrus fruits, which greatly restricts the transportation and sales of Shatang Tangerine. Therefore, post-harvest anti-corrosion treatment is an important part of the storage and preservation of sugar oranges. At present, chemical preservatives are commonly used in the storage and production of citrus, but they have many toxic residues and have certain adverse effects on human health.

Chitosan comes from animals, plants and microorganisms. It has a wide range of raw materials, non-toxic, non-polluting, biodegradable, and environmentally friendly. With the in-depth study of chitosan, it has been found that it has antiseptic, insecticidal and anti-pathogenic fungi. Chitin extracted from insects and chitosan prepared are a new way to develop and utilize insect resources.

Fludioxonil (Fludioxonil) is a contact fungicide. It inhibits the growth of hyphae by inhibiting the transport related to glucose phosphorylation, which ultimately leads to the death of pathogens, and can prevent seed-borne fungi and soil-borne fungal diseases. Due to its high efficiency and low toxicity, the Ministry of Health, Labor and Welfare of Japan approved fludioxonil as a food additive and formulated standards for this substance.

Summary of the invention

The purpose of the present invention is to provide a fresh-keeping agent for citrus oranges containing chitosan derived from black flies.

The present invention is a sugar orange preservative or Penicillium citrus inhibitor with chitosan and fludioxonil from black water fly as the main active ingredients, and is characterized in that the effective ingredients are chitosan and fludioxonil from black water fly The composition of bacteronitrile, and its mass ratio is (49-1):1.

Preferably, the chitosan derived from black water horsefly is chitosan derived from black water horsefly pupa, that is, chitosan prepared from black water horsefly pupa shell as a raw material.

Preferably, the mass ratio of chitosan and fludioxonil from black water fly is (49-9):1 composition, more preferably 29:1 composition.

According to the present invention, through experiments, it is found that the black water fly-source chitosan and fludioxonil have a synergistic effect on the fresh-keeping of tangtang oranges after being mixed with fludioxonil. The advantages of the present invention are that after mixing chitosan from black water fly and fludioxonil, it can broaden the use of chitosan from black water fly; Nitrile adheres to the surface of the sugar orange fruit, so as to achieve the effect of synergistic preservation; third, it can prevent and overcome the resistance of harmful bacteria to fludioxonil and prolong the service life of fludioxonil.

Detailed ways

The following examples are to further illustrate the present invention, but not to limit the present invention.

The inventor passed the indoor formula screening test and found that the mixture of chitosan and fludioxonil has a synergistic effect on the fresh-keeping of tangtang oranges.

In order to better understand the essence of the present invention, the technical content of the present invention will be described in detail below in conjunction with examples, but the content of the present invention is not limited to this, and cannot therefore be understood as a limitation on the patent scope of the present invention.

The chitosan used in the following examples is chitosan derived from Heishui horsefly (Heishui horsefly chitosan). The preparation method can refer to the patent number: ZL 201210018461.2, the name of the invention: a chitosan extracted from Heishui horsefly Sugar preparation method.

The specific preparation method is:

Soak 100g of black water fly pupa shells in 600mL 4% (mass fraction) hydrochloric acid at room temperature (26℃) for 12h. After washing to neutrality, bake in a 60℃ drying oven for 6h; then use 6% (mass fraction) Soak the NaOH solution in a water bath at 80°C for 5h, wash to neutrality, and bake it in a drying oven at 60°C for 6h; weigh 4g of the dried sample and soak it in 20mL 4% (mass fraction) HCl solution for 1 hour, and then add 80mL NaClO The solution (available chlorine mole fraction 2.0%) was treated in a water bath at 80°C for 3 hours, and dried to obtain a chitin sample, which was stored in the refrigerator for later use.

The color of the extracted chitin product is white, and the average extraction rate of chitin in the pupa shell of the black water fly is 11.7%. Add 1 drop of 0.03% (mass fraction) iodine-potassium iodide solution and 1 drop of 1% (mass fraction) sulfuric acid to the extracted chitin. The white porcelain spot sample plate shows purple-brown, and then add a few drops of 75% (mass fraction) Fraction) Sulfuric acid, the purple color is found to disappear gradually, indicating that the test substance is chitin.

Weigh 3g of the extracted chitin sample and place it in 120mL 50% (mass fraction) NaOH solution, react in a 100℃ water bath for 4 hours, wash with water until neutral; then add 120mL 50% (mass fraction) NaOH at 90℃ Reacted in a water bath for 1 hour, washed with water to neutrality and dried in a drying oven at 60°C for 8 hours. The degree of deacetylation was determined to be 73.52%, and the obtained sample was chitosan.

Example 1

After the sugar orange fruit is picked, Penicillium citrus is one of the main diseases during the storage period of citrus. Therefore, the present invention uses the hypha growth rate method to determine the toxicity of chitosan and fludioxonil to Penicillium italicum Force and calculate EC ₅₀ . The specific experimental steps are as follows:

1. Mix chitosan and fludioxonil in mass ratios of 49:1, 39:1, 29:1, 19:1, 9:1, and 1:1 to form each test sample.

2. Mycelial growth rate method: mix the test samples (chitosan, fludioxonil, chitosan and fludioxonil according to the mass ratio of 49:1, 39:1, 29:1, 19) with sterile water: 1, 9:1, 1:1) Prepare a certain concentration of the test drug solution, accurately pipette 1ml of the drug solution into 9mL of melted PDA medium (about 50℃), mix well and pour it into a sterilized petri dish (9cm in diameter), prepare a poisonous medium of the required concentration, mix with the same volume of sterile water as a blank control. Add 10 mL of PDA medium to a petri dish with a diameter of 9 cm, and access the test pathogen (penicillium citrinum) for culture. When the mycelium is about to grow over the entire petri dish, use a sterilized punch to make a 6mm fungus cake at the edge of the petri dish where the hyphae grows vigorously, and inoculate it in the center of the poisonous medium (one with hyphae). Face down). Place a bacterial cake per petri dish, and repeat each treatment 3 times. Incubate at a constant temperature of 27°C, observe the growth of the colony after 7 days, use the cross method to determine the diameter of the colony, and calculate the inhibition rate according to the following formula.

Colony Diameter (cm) = Measured Colony Diameter-Bacterial Cake Diameter

_{The virulence curve equation and EC 50 were} calculated according to the inhibition rate value and the concentration log value. Calculate the co-toxicity coefficient (CTC) according to the method of Sun Yunpei (1960), compare the antibacterial effect of each mixture, and evaluate its synergistic effect.

From the results in Table 1, it can be seen that when the ratio of chitosan to fludioxonil is 29:1, the co-toxicity coefficient is the highest, 333.45, and the synergistic effect is the best.

Table 1: 7-day virulence test results of each single agent and its mixed pair of Penicillium citrus

Example 2

The chitosan and fludioxonil were mixed according to a mass ratio of 29:1, and then dissolved in water to make a 200mg/L solution. The control chitosan and fludioxonil were 193.33mg/L and 6.67mg/L solutions (the solvent was water). Choose fresh, non-mechanical damage, disease and insect pests, and uniformly sized sugar oranges, and randomly group them into groups, 30 in each group, and set up three repetitions. Soak the sugar tangerines in each prepared solution for 5 seconds, remove them with a colander, and place them on a white porcelain plate to air dry. Take the sugar tangerines soaked in clear water for 5 seconds as a blank control. The same conditions are at room temperature. Stored (25°C) for 35 days, measured the good fruit rate, and evaluated the preservation effect.

The evaluation standard of good fruit rate is: moldy and rotten fruit is rated as rotten fruit, and the fruit without moldy and rotten is a good fruit.

Good fruit rate=good fruit/all fruits×100%

The specific results are shown in Table 2. From the results of Table 2, it can be seen that when the ratio of chitosan to fludioxonil is 29:1, the good fruit rate of 35 days after the treatment of tangtang orange with 200mg/L liquid medicine has reached 100%.

Table 2 The 35-day preservation effect of chitosan to fludioxonil at a ratio of 29:1

Claims

A kind of sugar orange preservative or Penicillium citrus inhibitor containing chitosan derived from black water horsefly, which is characterized in that it comprises chitosan derived from black water horsefly and fludioxonil, and its mass ratio is (49～1) :1.
The antistaling agent for citrus oranges or Penicillium citrus inhibitor containing chitosan derived from black water fly according to claim 1, wherein the chitosan derived from black water fly is based on black water fly pupa shell Chitosan prepared as a raw material.
The sugar orange preservative or Penicillium citrus inhibitor containing chitosan derived from black horsefly according to claim 1 or 2, characterized in that the combination of chitosan derived from black horsefly and fludioxonil The mass ratio is (49-9):1.
The fresh-keeping agent for sugar orange or Penicillium citrus inhibitor containing chitosan derived from black water fly according to claim 1, wherein the mass ratio of chitosan derived from black water fly to fludioxonil It is 29:1.