A postharvest plant preservative for citrus comprising an extract of loquat leaf
By using loquat leaf extract as the main ingredient, a postharvest plant preservative for citrus has been developed, which solves the problem of toxic side effects of chemical preservatives and achieves effective prevention and control of citrus blue mold and green mold, without causing environmental pollution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGXI AGRICULTURAL UNIVERSITY
- Filing Date
- 2018-03-21
- Publication Date
- 2026-06-30
AI Technical Summary
In the current post-harvest storage process of citrus, chemical preservatives have residual toxic side effects due to fungicide residues, and there is a lack of effective natural plant-derived antibacterial agents for the prevention and control of citrus blue mold and green mold.
Using loquat leaf extract as the main component, combined with film-forming agents, solubilizers, preservatives, pH adjusters, osmotic pressure regulators, antioxidants and water, a postharvest plant preservative for citrus was prepared. It was applied to the surface of citrus by spraying or coating, and significantly inhibited Penicillium and Green mold.
This preservative is highly effective in controlling Penicillium and Green mold diseases in citrus fruits, and it leaves no chemical residues, is harmless to humans and the environment, and has good application value.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of postharvest preservation technology for citrus, and particularly to a postharvest plant preservative for citrus containing loquat leaf extract. Background Technology
[0002] Citrus fruits are the world's largest fruit category and, in my country, the second largest after apples. They are also the third largest internationally traded agricultural product, after wheat and corn. Postharvest rot is one of the major problems in the storage and distribution of citrus fruits. More than 20 types of microbial diseases can occur during postharvest storage of citrus fruits. Blue mold and green mold, caused by *Penicillium italicum* and *Penicillium digitatum*, are the two most common postharvest diseases, accounting for 90% of postharvest rot. Therefore, research on postharvest storage and preservation technologies for citrus fruits has received increasing attention. Chemical methods are currently the most widely used postharvest treatment methods for citrus fruits, but they are prone to causing toxic side effects from fungicide residues. In recent years, the search for natural plant-derived antibacterial agents from edible plant resources for postharvest preservation of citrus fruits has attracted great attention from researchers worldwide.
[0003] Loquat leaves are the dried leaves of the loquat tree [Eriobotrya Japonca (Thunb.) Lind], a plant in the Rosaceae family. They are a commonly used traditional Chinese medicine, characterized by their bitter, slightly pungent, and slightly cold nature. Medicinally, they are associated with the lung and stomach meridians, clearing the lungs and relieving cough, as well as suppressing nausea and vomiting. They mainly contain active ingredients such as triterpenoids, volatile oils, oleanolic acids, flavonoids, polyphenols, sesquiterpenes, and glycosides.
[0004] Currently, there is limited research on the antibacterial activity of loquat leaves. Some studies have found that loquat leaf extract exhibits good antibacterial activity against three common food contaminants (Escherichia coli, Staphylococcus aureus, and Bacillus subtilis) (Xiao Xinsheng, Lin Qianying. Study on the antibacterial effect of loquat leaf extract [J]. Modern Food Science and Technology, 2010, 26(1):59-62.); loquat leaf extract shows strong antibacterial activity against bacteria such as Escherichia coli and Bacillus subtilis, but relatively weak antibacterial activity against fungi such as Rhizopus, Aspergillus, and Rhizopus oryzae, and no antibacterial effect against Saccharomyces cerevisiae (Xie Hongying, Liu Yi, Wang Hongxin, Zhang Jing, Qin Yun. Study on the antioxidant and antibacterial effects of loquat leaf extract [J]. Food Industry, 2007, 29(2):1-4.). In addition, the total flavonoid extract of loquat leaves showed strong inhibitory effects on bacteria such as Escherichia coli, Bacillus subtilis, and Staphylococcus aureus, but poor inhibitory effects on Aspergillus flaus, Saccharomyes cerevisiue, and Penicillium lrwrdinme Arenicola sp. (Chen Jun, Zhao Li, Li Yajie. Study on ultrasonic-assisted extraction and antibacterial effect of total flavonoids from loquat leaves [J]. Hubei Agricultural Sciences, 2013, 52(10): 2383-2385. Mao Yanni. Study on extraction and antibacterial properties of flavonoids from loquat leaves [D]. Fujian Agriculture and Forestry University, 2010. p38). Although some studies have reported the antibacterial activity of total flavonoid extract of loquat leaves against Penicillium, the results were negative.
[0005] Regarding patents related to loquat leaf extract, patent CN200610069043.0 discloses a method for preparing and using a water-based loquat leaf extract. This patent uses water as a solvent to extract loquat leaf saponins, flavonoids, and amygdalin as the main medicinal components. Patent CN200810219932.X discloses a method for preparing loquat leaf extract, which also provides a method for preparing a water-based loquat leaf extract. This method has a high degree of flavonoid enrichment, and the total flavonoid content in the extract is higher than 50%. Patent CN201510232630.6 discloses a... A method for the combined preparation of flavonoids and triterpene acids from loquat leaves involves eluting fresh loquat leaves with dimethyl carbonate solution to obtain an extract, followed by vacuum concentration and recrystallization to obtain a flavonoid extract. The loquat leaf residue is then eluted with ethanol solution, followed by vacuum concentration and recrystallization to obtain a triterpene acid extract. Patent CN201410802741.1 discloses a total sesquiterpene glycoside extract from loquat leaves, its preparation method, and its application. This method involves reflux extraction of dried loquat leaves with a certain concentration of ethanol, followed by filtration, concentration, centrifugation, and chromatography to obtain the total sesquiterpene glycoside extract.
[0006] In summary, there are currently no reports on postharvest plant preservatives for citrus fruits with loquat leaf extract as the main active ingredient. For these reasons, this invention develops a postharvest plant preservative for citrus fruits containing loquat leaf extract, providing a new approach to postharvest preservation of citrus fruits. Summary of the Invention
[0007] In order to overcome the shortcomings of the prior art, the present invention provides a postharvest plant preservative for citrus containing loquat leaf extract. This preservative has the characteristics of significant antibacterial effect, no chemical residue, and no environmental pollution.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0009] A postharvest preservative for citrus fruits containing loquat leaf extract, comprising the following ingredients in parts by weight:
[0010] Loquat leaf extract 6.25-50 parts, film-forming agent 0.5-2.0 parts, solubilizer 0.5-1.0 parts, preservative 0.5-1.5 parts, pH
[0011] Value regulator 0.5-1.0 parts, osmotic pressure regulator 0.5-2.0 parts, antioxidant 0.5-3.0 parts, water 1000 parts.
[0012] Preferably, the preservative comprises the following components in parts by weight:
[0013] 50 parts loquat leaf extract, 1.5 parts film-forming agent, 0.8 parts solubilizer, 1.0 part preservative, and 0.8 parts pH adjuster.
[0014] 1 part, 1.0 part of osmotic pressure regulator, 1.2 parts of antioxidant, and 1000 parts of water.
[0015] Preferably, the cosolvent is selected from at least one of glycerol, sucrose ester, and Tween series; the preservative is selected from at least one of potassium sorbate and sodium benzoate; the pH adjuster is selected from at least one of citric acid, acetic acid, lactic acid, and tartaric acid; the osmotic pressure adjuster is selected from at least one of calcium propionate, calcium chloride, sodium chloride, and calcium carbonate; the antioxidant is selected from vitamin C and polyphenols; and the water is sterile water.
[0016] Preferably, the film-forming agent is selected from at least one of sodium carboxymethyl cellulose, sodium alginate, chitosan, and chitin.
[0017] Preferably, the osmotic pressure regulator is selected from at least one of calcium propionate, calcium chloride, sodium chloride, and calcium carbonate.
[0018] More preferably, the preservative further includes the following components in parts by weight:
[0019] 1.0-1.5 parts of plant growth regulator.
[0020] More preferably, the plant growth regulator is selected from at least one of 2,4-dichlorophenoxyacetic acid and abscisic acid.
[0021] Preferably, the preservative can be formulated as a liquid or nanoemulsion, and the preservative can be directly sprayed or applied to the surface of the harvested citrus fruit for preservation.
[0022] Compared with the prior art, the beneficial effects of the present invention are:
[0023] (1) This invention uses loquat leaf extract, a natural Chinese herbal medicine, as the main active ingredient to prepare a new type of citrus postharvest preservative. It makes full use of the obvious antibacterial effect of loquat leaf extract and rationally and scientifically combines other auxiliary ingredients to make the preservative have the characteristics of good preservation effect, no chemical residue, no health hazards to the human body, and no pollution to the environment, and has great application value.
[0024] (2) The biocontrol test of the postharvest preservative for citrus prepared by the present invention with loquat leaf extract as the main active ingredient showed that the biocontrol effect of the preservative on citrus postharvest blue mold and green mold was 14.43%-36.81% and 23.85%-48.79% respectively, both achieving good control effects, especially the control effect on green mold was more significant. Detailed Implementation
[0025] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0026] Example 1:
[0027] Biocontrol effect of a postharvest plant preservative for citrus containing loquat leaf extract against postharvest Penicillium and Green mold in citrus.
[0028] 1. Experimental materials:
[0029] ① Test drug: A postharvest preservative for citrus fruits containing loquat leaf extract. The formulation of this preservative is as follows:
[0030] Loquat leaf extract 6.25 parts, sodium carboxymethyl cellulose 0.5 parts, glycerin 0.5 parts, potassium sorbate 0.5 parts, citric acid 0.5 parts, calcium propionate 0.5 parts, vitamin C 0.5 parts, water 1000 parts.
[0031] ② Test strains: Penicillium italicum (ACCC30399) and Penicillium digitatum (ACCC30389) were both from the China Agricultural Microbial Culture Collection Center (ACCC).
[0032] 2. Experimental methods:
[0033] After disinfecting the Xinyu tangerines with a 2% NaClO solution, they were rinsed thoroughly with sterile water and then air-dried for later use. Before the experiment, a 4mm diameter, 3mm deep wound was made on the waist of the fruit using a sterilized inoculation needle. The experiment consisted of two parts:
[0034] (1) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest Penicillium rot in citrus:
[0035] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL of Penicillium italicum spore suspension;
[0036] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium italicum spores was inoculated into wounds on citrus fruits as a positive control.
[0037] (2) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest green mold of citrus:
[0038] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL Penicillium finger spore suspension;
[0039] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium finger spores was inoculated into wounds on citrus fruits as a positive control.
[0040] Finally, place the treated fruit on a tray, cover it with a thin film bag, treat 6 fruits for each treatment, repeat the experiment 3 times, maintain the relative humidity at about 95%, and incubate at 27℃ for 7 days. After incubation, investigate the diameter of lesions on the citrus fruit and calculate the control effect according to the following formula.
[0041] Control efficacy (%) = 100 × (average lesion diameter in the positive control group - average lesion diameter in the preservative-treated group) / lesion diameter in the positive control group
[0042] 3. Experimental Results:
[0043] (1) Experimental results show that the postharvest plant preservative containing loquat leaf extract has a significant control effect on postharvest Penicillium rot in citrus. As shown in Table 1, the control effect on Italian Penicillium rot was 14.43% after 7 days of treatment on citrus.
[0044] Table 1. Effect of a postharvest plant preservative containing loquat leaf extract on the control of Penicillium mold in citrus.
[0045]
[0046] (2) The experimental results showed that the postharvest plant preservative containing loquat leaf extract had a significant control effect on postharvest green mold of citrus. As shown in Table 2, the control effect on green mold was 23.85% after 7 days of treatment of citrus.
[0047] Table 2. Effects of a postharvest plant preservative containing loquat leaf extract on the control of citrus green mold.
[0048]
[0049] Example 2:
[0050] Biocontrol effect of a postharvest plant preservative for citrus containing loquat leaf extract against postharvest Penicillium and Green mold in citrus.
[0051] 1. Experimental materials:
[0052] ① Test drug: A postharvest preservative for citrus fruits containing loquat leaf extract. The formulation of this preservative is as follows:
[0053] 25 parts loquat leaf extract, 1.0 part film-forming agent (composed of sodium carboxymethyl cellulose and sodium alginate in a 1:1 ratio), 0.8 parts sucrose ester, 1.0 part potassium sorbate, 0.7 parts acetic acid, 1.0 part calcium chloride, 1.2 parts vitamin C, and 1000 parts water.
[0054] ② Test strains: Penicillium italicum (ACCC30399) and Penicillium digitatum (ACCC30389) were both from the China Agricultural Microbial Culture Collection Center (ACCC).
[0055] 2. Experimental methods:
[0056] After disinfecting the Xinyu tangerines with a 2% NaClO solution, they were rinsed thoroughly with sterile water and then air-dried for later use. Before the experiment, a 4mm diameter, 3mm deep wound was made on the waist of the fruit using a sterilized inoculation needle. The experiment consisted of two parts:
[0057] (1) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest Penicillium rot in citrus:
[0058] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL of Penicillium italicum spore suspension;
[0059] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium italicum spores was inoculated into wounds on citrus fruits as a positive control.
[0060] (2) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest green mold of citrus:
[0061] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL Penicillium finger spore suspension;
[0062] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium finger spores was inoculated into wounds on citrus fruits as a positive control.
[0063] Finally, place the treated fruit on a tray, cover it with a thin film bag, treat 6 fruits for each treatment, repeat the experiment 3 times, maintain the relative humidity at about 95%, and incubate at 27℃ for 7 days. After incubation, investigate the diameter of lesions on the citrus fruit and calculate the control effect according to the following formula.
[0064] Control efficacy (%) = 100 × (average lesion diameter in the positive control group - average lesion diameter in the preservative-treated group) / lesion diameter in the positive control group
[0065] 3. Experimental Results:
[0066] (1) The experimental results show that the postharvest plant preservative containing loquat leaf extract has a significant control effect on postharvest Penicillium rot in citrus. As shown in Table 1, the control effect on Italian Penicillium rot was 23.83% after 7 days of treatment on citrus.
[0067] Table 1. Effect of a postharvest plant preservative containing loquat leaf extract on the control of Penicillium mold in citrus.
[0068]
[0069] (2) The experimental results showed that the postharvest plant preservative containing loquat leaf extract had a significant control effect on postharvest green mold of citrus. As shown in Table 2, the control effect on green mold was 40.03% after 7 days of treatment of citrus.
[0070] Table 2. Effects of a postharvest plant preservative containing loquat leaf extract on the control of citrus green mold.
[0071]
[0072] Example 3:
[0073] Biocontrol effect of a postharvest plant preservative for citrus containing loquat leaf extract against postharvest Penicillium and Green mold in citrus.
[0074] 1. Experimental materials:
[0075] ① Test drug: A postharvest preservative for citrus fruits containing loquat leaf extract. The formulation of this preservative is as follows:
[0076] The ingredients are: 60 parts loquat leaf extract, 1.5 parts film-forming agent (composed of sodium alginate, chitosan and chitin in a 1:1:1 ratio), 0.9 parts sucrose ester, 1.2 parts sodium benzoate, 0.85 parts lactic acid, 1.6 parts osmotic pressure regulator (composed of calcium chloride, sodium chloride and calcium carbonate in a 1:1:1 ratio), 2.0 parts polyphenols, and 1000 parts water.
[0077] ② Test strains: Penicillium italicum (ACCC30399) and Penicillium digitatum (ACCC30389) were both from the China Agricultural Microbial Culture Collection Center (ACCC).
[0078] 2. Experimental methods:
[0079] After disinfecting the Xinyu tangerines with a 2% NaClO solution, they were rinsed thoroughly with sterile water and then air-dried for later use. Before the experiment, a 4mm diameter, 3mm deep wound was made on the waist of the fruit using a sterilized inoculation needle. The experiment consisted of two parts:
[0080] (1) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest Penicillium rot in citrus:
[0081] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL of Penicillium italicum spore suspension;
[0082] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium italicum spores was inoculated into wounds on citrus fruits as a positive control.
[0083] (2) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest green mold of citrus:
[0084] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL Penicillium finger spore suspension;
[0085] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium finger spores was inoculated into wounds on citrus fruits as a positive control.
[0086] Finally, place the treated fruit on a tray, cover it with a thin film bag, treat 6 fruits for each treatment, repeat the experiment 3 times, maintain the relative humidity at about 95%, and incubate at 27℃ for 7 days. After incubation, investigate the diameter of lesions on the citrus fruit and calculate the control effect according to the following formula.
[0087] Control efficacy (%) = 100 × (average lesion diameter in the positive control group - average lesion diameter in the preservative-treated group) / lesion diameter in the positive control group
[0088] 3. Experimental Results:
[0089] (1) The experimental results show that the postharvest plant preservative containing loquat leaf extract has a significant control effect on postharvest Penicillium rot in citrus. As shown in Table 1, the control effect on Italian Penicillium rot was 36.24% after 7 days of treatment on citrus.
[0090] Table 1. Effect of a postharvest plant preservative containing loquat leaf extract on the control of Penicillium mold in citrus.
[0091]
[0092] (2) The experimental results showed that the postharvest plant preservative containing loquat leaf extract had a significant control effect on postharvest green mold of citrus. As shown in Table 2, the control effect on green mold was 47.98% after 7 days of treatment of citrus.
[0093] Table 2. Effects of a postharvest plant preservative containing loquat leaf extract on the control of citrus green mold.
[0094]
[0095] Example 4:
[0096] Biocontrol effect of a postharvest plant preservative for citrus containing loquat leaf extract against postharvest Penicillium and Green mold in citrus.
[0097] 1. Experimental materials:
[0098] ① Test drug: A postharvest preservative for citrus fruits containing loquat leaf extract. The formulation of this preservative is as follows:
[0099] Loquat leaf extract 6.25 parts, sodium carboxymethyl cellulose 0.5 parts, glycerin 0.5 parts, potassium sorbate 0.5 parts, citric acid 0.5 parts, calcium propionate 0.5 parts, vitamin C 0.5 parts, 2,4-dichlorophenoxyacetic acid 1.0 part, water 1000 parts.
[0100] ② Test strains: Penicillium italicum (ACCC30399) and Penicillium digitatum (ACCC30389) were both from the China Agricultural Microbial Culture Collection Center (ACCC).
[0101] 2. Experimental methods:
[0102] After disinfecting the Xinyu tangerines with a 2% NaClO solution, they were rinsed thoroughly with sterile water and then air-dried for later use. Before the experiment, a 4mm diameter, 3mm deep wound was made on the waist of the fruit using a sterilized inoculation needle. The experiment consisted of two parts:
[0103] (1) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest Penicillium rot in citrus:
[0104] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL of Penicillium italicum spore suspension;
[0105] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium italicum spores was inoculated into wounds on citrus fruits as a positive control.
[0106] (2) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest green mold of citrus:
[0107] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL Penicillium finger spore suspension;
[0108] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium finger spores was inoculated into wounds on citrus fruits as a positive control.
[0109] Finally, place the treated fruit on a tray, cover it with a thin film bag, treat 6 fruits for each treatment, repeat the experiment 3 times, maintain the relative humidity at about 95%, and incubate at 27℃ for 7 days. After incubation, investigate the diameter of lesions on the citrus fruit and calculate the control effect according to the following formula.
[0110] Control efficacy (%) = 100 × (average lesion diameter in the positive control group - average lesion diameter in the preservative-treated group) / lesion diameter in the positive control group
[0111] 3. Experimental Results:
[0112] (1) The experimental results show that the postharvest plant preservative containing loquat leaf extract has a significant control effect on postharvest Penicillium rot in citrus. As shown in Table 1, the control effect on Italian Penicillium rot was 15.20% after 7 days of treatment on citrus.
[0113] Table 1. Effect of a postharvest plant preservative containing loquat leaf extract on the control of Penicillium mold in citrus.
[0114]
[0115] (2) The experimental results showed that the postharvest plant preservative containing loquat leaf extract had a significant control effect on postharvest green mold of citrus. As shown in Table 2, the control effect on green mold was 24.25% after 7 days of treatment of citrus.
[0116] Table 2. Effects of a postharvest plant preservative containing loquat leaf extract on the control of citrus green mold.
[0117]
[0118] Example 5:
[0119] Biocontrol effect of a postharvest plant preservative for citrus containing loquat leaf extract against postharvest Penicillium and Green mold in citrus.
[0120] 1. Experimental materials:
[0121] ① Test drug: A postharvest preservative for citrus fruits containing loquat leaf extract. The formulation of this preservative is as follows:
[0122] The ingredients are: 60 parts loquat leaf extract, 1.5 parts film-forming agent (composed of sodium alginate, chitosan and chitin in a 1:1:1 ratio), 0.9 parts sucrose ester, 1.2 parts sodium benzoate, 0.85 parts lactic acid, 1.6 parts osmotic pressure regulator (composed of calcium chloride, sodium chloride and calcium carbonate in a 1:1:1 ratio), 2.0 parts polyphenols, 1.5 parts plant growth regulator (composed of 2,4-dichlorophenoxyacetic acid and abscisic acid in a 1:1 ratio), and 1000 parts water.
[0123] ② Test strains: Penicillium italicum (ACCC30399) and Penicillium digitatum (ACCC30389) were both from the China Agricultural Microbial Culture Collection Center (ACCC).
[0124] 2. Experimental methods:
[0125] After disinfecting the Xinyu tangerines with a 2% NaClO solution, they were rinsed thoroughly with sterile water and then air-dried for later use. Before the experiment, a 4mm diameter, 3mm deep wound was made on the waist of the fruit using a sterilized inoculation needle. The experiment consisted of two parts:
[0126] (1) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest Penicillium rot in citrus:
[0127] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL of Penicillium italicum spore suspension;
[0128] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium italicum spores was inoculated into wounds on citrus fruits as a positive control.
[0129] (2) Biocontrol experiment of postharvest plant preservatives for citrus containing loquat leaf extract against postharvest green mold of citrus:
[0130] ① First, treat the wounds on the citrus fruit with 20 μL of preservative using a micropipette, then inoculate with 20 μL of 1×10 6 CFU / mL Penicillium finger spore suspension;
[0131] ② Inoculate 20 μL of sterile water into the wound on the citrus fruit, then add 20 μL of 1×10 6 A CFU / mL suspension of Penicillium finger spores was inoculated into wounds on citrus fruits as a positive control.
[0132] Finally, place the treated fruit on a tray, cover it with a thin film bag, treat 6 fruits for each treatment, repeat the experiment 3 times, maintain the relative humidity at about 95%, and incubate at 27℃ for 7 days. After incubation, investigate the diameter of lesions on the citrus fruit and calculate the control effect according to the following formula.
[0133] Control efficacy (%) = 100 × (average lesion diameter in the positive control group - average lesion diameter in the preservative-treated group) / lesion diameter in the positive control group
[0134] 3. Experimental Results:
[0135] (1) The experimental results show that the postharvest plant preservative containing loquat leaf extract has a significant control effect on postharvest Penicillium rot in citrus. As shown in Table 1, the control effect on Italian Penicillium rot was 36.81% after 7 days of treatment on citrus.
[0136] Table 1. Effect of a postharvest plant preservative containing loquat leaf extract on the control of Penicillium mold in citrus.
[0137]
[0138] (2) The experimental results showed that the postharvest plant preservative containing loquat leaf extract had a significant control effect on postharvest green mold of citrus. As shown in Table 2, the control effect on green mold was 48.79% after 7 days of treatment of citrus.
[0139] Table 2. Effects of a postharvest plant preservative containing loquat leaf extract on the control of citrus green mold.
[0140]
[0141] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.
Claims
1. A postharvest plant preservative for citrus fruits containing loquat leaf extract, characterized in that: The preservative is composed of the following components in parts by weight: The ingredients include 6.25-50 parts loquat leaf extract, 0.5-2.0 parts film-forming agent, 0.5-1.0 parts solubilizer, 0.5-1.5 parts preservative, 0.5-1.0 parts pH adjuster, 0.5-2.0 parts osmotic pressure adjuster, 0.5-3.0 parts antioxidant, 1000 parts water, and 1.0-1.5 parts plant growth regulator. The cosolvent is selected from at least one of glycerol, sucrose esters, and Tween series; the preservative is selected from potassium sorbate and sodium benzoate; the pH adjuster is selected from at least one of citric acid, acetic acid, lactic acid, and tartaric acid; the osmotic pressure adjuster is selected from at least one of calcium propionate, calcium chloride, sodium chloride, and calcium carbonate; the antioxidant is selected from vitamin C and polyphenols; the water is sterile water; the film-forming agent is selected from at least one of sodium carboxymethyl cellulose, sodium alginate, chitosan, and chitin; the plant growth regulator is selected from at least one of 2,4-dichlorophenoxyacetic acid and abscisic acid. The preservative is made into a liquid and is sprayed or applied directly to the surface of the citrus fruit after harvest to preserve its freshness. The liquid includes nanoemulsions.