Calyx removing agent for improving quality of Korla bergamot pears and preparation method of calyx removing agent

Abstract

The invention provides a calyx-removing agent for improving the quality of Korla pear and a preparation method thereof, and belongs to the technical field of fruit tree planting, the calyx-removing agent is zein-chitosan-soybean oil Pickering emulsion composed of 50-250 ppm of methyl jasmonate, 50-250 ppm of naphthyl o-carbamylbenzoic acid and 50-250 ppm of 5-ALA, the methyl jasmonate is dissolved in soybean oil, the chitosan is dissolved in the soybean oil, the 5-ALA is dissolved in the chitosan, the chitosan is dissolved in the soybean oil, and the 5-ALA is dissolved in the chitosan. The preparation method comprises the following steps: dissolving naphthyl o-carbamoylbenzoic acid and 5-ALA in a zein-chitosan solution; the method is simple and low in cost, after the stable Pickering emulsion prepared by mixing three different substances is sprayed, the proportion of fruits without calyx is remarkably increased through the multi-way synergistic effect, the comprehensive quality of the fruits is improved, the method has the technical advantages of being environmentally friendly, efficient and safe, the proportion and quality of the fruits without calyx of the Korla pear fruits can be effectively increased, the acidity can be effectively reduced, and the quality of the fruits without calyx of the Korla pear fruits can be effectively improved. The content of vitamin C is increased, and the economic value is very high.

Description

Technical Field

[0001] This invention belongs to the field of fruit tree planting technology, specifically relating to a calyx-removing agent for improving the quality of Korla fragrant pears and its preparation method. Background Technology

[0002] Korla fragrant pears, a landmark product of Xinjiang's distinctive forestry and fruit industry, are renowned in domestic and international markets for their unique aroma, delicate taste, and extremely high nutritional value. In their natural state, Korla fragrant pears are divided into two types: those with detached sepals and those with persistent sepals. In the main production areas of Korla fragrant pears, detached sepals are considered the representative of high-quality fruit, enjoying higher market recognition and prices. Compared to persistent sepals, detached sepals have a more aesthetically pleasing appearance, a more regular shape, a smaller core, and fewer stone cells. During the young fruit development stage, the vascular bundles of the calyx tube in detached sepals are not fully developed, leading to insufficient water and nutrient supply, causing the sepals to fall off naturally. In contrast, the vascular bundles of the calyx tube in persistent sepals are well-developed, continuously supplying nutrients and keeping the sepals intact. This nutrient retention effect concentrates more nutrients in the fruit itself, improving quality. However, currently, under natural conditions, the proportion of persistent sepals on a single tree is as high as 70%-85%. This excessively high proportion severely restricts the overall quality improvement of fragrant pears and has become a key technical bottleneck affecting the high-quality development of the Korla fragrant pear industry. Currently, production mainly relies on spraying plant growth regulators (such as female pear agent) to control calyx removal. However, long-term use of such chemical regulators can easily lead to premature aging of the trees, decreased stress resistance, and other growth and development obstacles, which is detrimental to the green and sustainable development of the industry. Therefore, the production of Korla fragrant pears urgently needs to develop green, efficient, and safe calyx removal control technology, which can significantly increase the proportion of calyx-free fruit and improve the overall quality of the fruit. This has important practical significance and broad application prospects for enhancing the commercial value of fragrant pears and promoting the quality and efficiency of the industry.

[0003] Methyl jasmonic acid (MeJA) is a commonly used plant growth regulator. It is a methyl esterified derivative of jasmonic acid and is widely distributed in plants. As a natural hormone in plant tissues, MeJA is considered an important cell regulatory factor that participates in various physiological and biochemical processes related to seed germination, growth and development, and has a good effect on improving fruit quality.

[0004] Naphthyl-o-carbamoylbenzoic acid (NPA), also known as naphthyl-o-carbamoylamine or oxychloride, is a specific inhibitor of auxin polar transport. Its main uses include: * **Inhibition of auxin transport:** NPA specifically inhibits the polar transport of auxins (such as indoleacetic acid) in plants, and is often used to study the role of auxins in plant development, such as root phototropism, geotropism, and organ formation. * **Regulation of plant growth:** By interfering with auxin distribution, NPA can affect seed germination, root development, and stem elongation, providing a tool for agricultural breeding or research on plant hormone mechanisms. * **As a research reagent:** In the laboratory, NPA is used to simulate perturbations in the auxin signaling pathway, helping to elucidate the role of second messengers such as calcium ions in plant responses.

[0005] Aminolevulinic acid is a naturally occurring functional non-protein amino acid in organisms. It plays a regulatory role in the synthesis of tetrapyrrole compounds such as heme, chlorophyll, and vitamin B12. It is a natural, non-toxic, biodegradable, and environmentally friendly plant growth regulator.

[0006] Because methyl jasmonate, naphthyl-o-carbamoylbenzoic acid, and 5-ALA have different solubilities and are all insoluble in water, mixing the three solutions is quite difficult, and can only be done using an emulsion method. No one has yet prepared an emulsion of these three substances for spraying onto plants. Summary of the Invention

[0007] To improve the decalyx rate, quality, taste, and related physicochemical indicators of Korla fragrant pears, this invention, based on previous research, provides a decalyx agent for enhancing the quality of Korla fragrant pears. The decalyx agent is a zein-chitosan-soybean oil Pickering emulsion composed of 50-250 ppm methyl jasmonic acid, 50-250 ppm naphthyl-o-carbamoylbenzoic acid, and 50-250 ppm 5-ALA. Methyl jasmonic acid is dissolved in soybean oil, while naphthyl-o-carbamoylbenzoic acid and 5-ALA are dissolved in the zein-chitosan solution.

[0008] The volume ratio of the zein-chitosan solution to the soybean oil is 1:9 to 2:8.

[0009] Meanwhile, the present invention also provides a method for preparing a calyx-removing agent to improve the quality of Korla fragrant pears, comprising the following steps: ① Dissolve naphthyl o-carbamoylbenzoic acid, 5-ALA, and zein powder in an ethanol solution and stir until fully dissolved to obtain a mixed zein solution; ② Dissolve chitosan in an aqueous acetic acid solution to obtain a chitosan solution. Add the mixed zein solution dropwise to an equal volume of chitosan solution, continue stirring, and remove ethanol to obtain a mixed zein-chitosan solution. ③ Dissolve methyl jasmonate in soybean oil and stir thoroughly to obtain an oil solution of methyl jasmonate; ④ Mix the oil solution of methyl jasmonate and the mixed zein-chitosan solution at a volume ratio of 1:9 to 2:8, and emulsify at high speed to obtain a composite decalyx agent that improves the quality of Korla fragrant pears. The final concentrations of methyl jasmonate, naphthyl-o-carbamoylbenzoic acid, and 5-ALA in the system were 50-250 ppm.

[0010] The final concentration of the zein is 0.05~0.2 g / L.

[0011] Specifically, the ethanol solution is an aqueous solution of ethanol with a volume fraction of 65-75%.

[0012] The method for removing ethanol involves evaporating ethanol at 30-38°C and under a vacuum of 0.01-0.2 MPa.

[0013] Specifically, the stirring is magnetic stirring at 200~2000 r / min for 0.5~4h.

[0014] The volume fraction of the acetic acid aqueous solution is 1-4%.

[0015] The final concentration of the chitosan is 0.05~0.2 g / L.

[0016] The high-speed emulsification is carried out at 5000~15000 r / min for 1~10 min. Beneficial effects

[0017] This invention focuses on inducing the formation of sepal abscission layer in Korla fragrant pear. Based on the plant hormone regulatory network and programmed cell death mechanism, it innovatively proposes a compound green sepal abscission agent formulation, whose effective components are methyl jasmonate (MeJA), 5-aminolevulinic acid (5-ALA), and N-1-naphthylphthalamic acid (NPA).

[0018] Since methyl jasmonate is a fat-soluble substance, while 5-aminolevulinic acid and naphthyl-o-benzoic acid are alcohol-soluble substances, and naphthyl-o-benzoic acid is a toxic substance, no one has yet used these three substances to remove the calyx of Korla fragrant pear. This invention is the first to use a dispersion composed of zein and chitosan to embed 5-aminolevulinic acid and naphthyl-o-benzoic acid, and then mix and emulsify it with an oil solution of methyl jasmonate to prepare a stable Pickering emulsion, thus obtaining a stable calyx-removing agent. According to the experimental results, the calyx removal rate and quality of Korla fragrant pears of the composite calyx-removing agent are significantly better than those of the single substance and the blank group, indicating that these three substances have a synergistic effect on the physiological function of Korla fragrant pears. The analysis mechanism is as follows.

[0019] Methyl jasmonic acid also plays a role in the abscission of Korla fragrant pear sepals. The main reason may be that methyl jasmonic acid can directly activate the ethylene signaling pathway and key genes in the abscission zone of the pear sepals, significantly increasing the ethylene content in the abscission zone, further inducing the synthesis of cell wall degrading enzymes in the abscission cells, and enhancing the sensitivity of cells to abscission signals. In addition, it has a certain synergistic effect with plant hormones such as auxin and abscisic acid. Methyl jasmonic acid can reduce the concentration of auxin in the abscission zone, reduce the inhibitory effect of auxin on abscission, and work with abscisic acid to regulate the hormone effects in the sepals, thereby promoting the abscission mechanism of Korla fragrant pear sepals.

[0020] Methyl jasmonic acid (MJJ) is a naturally occurring methyl esterified derivative of jasmonic acid in plants. As an important cell regulator, it can significantly increase the ethylene content in the abscission zone by activating the ethylene signaling pathway and key genes involved in synthesis in the abscission zone. This, in turn, induces the synthesis of cell wall degrading enzymes and enhances the cell's sensitivity to abscission signals. Simultaneously, MJJ can reduce the concentration of auxin in the abscission zone, decreasing its inhibitory effect on abscission, and synergistically regulates the hormonal effects in the sepals with abscisic acid, thereby effectively promoting sepal abscission in Korla pear. 5-Aminolevulinic acid (5-aminolevulinic acid) is a naturally occurring functional non-protein amino acid in organisms. As an environmentally friendly plant growth regulator, it promotes the homogenization of parenchyma cells by regulating cell division and differentiation in the abscission zone, creating a structural basis for cell wall degradation and cell separation. Naphthyl-o-carbamoylbenzoic acid (NPA), as a specific inhibitor of auxin polar transport, can precisely inhibit the transport of auxin from the sepals to the fruit, effectively reducing the auxin content in the abscission zone and significantly mitigating its inhibitory effect on sepal abscission. Meanwhile, NPA can regulate the expression of abscission-related genes such as PbARP, promoting programmed cell death in the abscission layer and thus accelerating sepal abscission in Korla fragrant pears. 5-ALA promotes the homogenization of thin-walled cells by regulating cell division and differentiation in the abscission zone, creating structural conditions for subsequent cell wall degradation and cell separation. Although 5-ALA does not directly affect plant hormone synthesis, it can indirectly influence the production of ethylene, auxin (IAA), and abscisic acid (ABA) by improving photosynthetic efficiency and energy supply, and there is a significant interaction mechanism between these substances, jointly affecting sepal abscission in Korla fragrant pears. 5-ALA can activate cellulase-degrading enzymes through ROS signaling and induce enzyme gene expression, ultimately affecting sepal abscission. Furthermore, the naturally low toxicity of 5-ALA makes it more suitable for the industrial needs of green cultivation of Korla fragrant pears.

[0021] Although aminolevulinic acid does not directly regulate plant hormone synthesis, it can indirectly affect the production of ethylene, auxin and abscisic acid by improving photosynthetic efficiency and energy supply. It can also activate the expression of cellulase genes through reactive oxygen species (ROS) signaling, thereby affecting sepal abscission. Its addition significantly improves fruit quality and sepal abscission.

[0022] In summary, this invention addresses the technological bottlenecks faced by the Korla fragrant pear industry by proposing a calyx-removing agent based on a compound of methyl jasmonate, 5-aminolevulinic acid, and naphthyl-o-carbamoylbenzoic acid. After spraying a stable Pickering emulsion prepared by mixing these three different substances, the agent exhibits a synergistic effect through multiple pathways, significantly increasing the proportion of decalyxed fruit and improving the overall quality of the fruit. Furthermore, it possesses the advantages of being green, efficient, and safe. Currently, there are no reports on the application of this three-component compound for regulating calyx removal in Korla fragrant pears. Detailed Implementation

[0023] The present invention will be described in detail below with reference to examples. All methods and techniques, unless otherwise specified, are conventional.

[0024] 5-ALA (99%, product number S30944, provided for research experiments only), naphthyl-o-carbamoylbenzoic acid (98%), CAS: 132-66-1 (product number S27387), and methyl jasmonic acid BR (95%, product number JP-0416) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. Other reagents were standard reagents.

[0025] Experimental methods (1) Single fruit weight, longitudinal and transverse diameters Five fruits were randomly selected from each of the four directions (east, south, west, and north) of each tree, resulting in 20 fruits per tree and a total of 60 fruits per treatment. The fruits were weighed using a 0.01% electronic balance, and the average weight was calculated to obtain the single fruit weight. The longitudinal and transverse diameters were measured using vernier calipers, and their average values ​​were also calculated. Fruit shape index: The fruit shape index is expressed as the ratio of the fruit's longitudinal diameter to its transverse diameter.

[0026] (2) Hardness The hardness was measured using a GY-1 hardness tester. Fifteen fruits were randomly selected from each treatment, and five fruits were randomly grouped together. The hardness of each pear was measured using a GY-1 hardness tester at four different locations, and the average value was calculated.

[0027] (3) Soluble solids The soluble solids content of each pear was measured using a digital refractometer. Fifteen fruits were randomly selected from each treatment, and five fruits were randomly grouped together. The soluble solids content of each pear was measured at four different locations using a digital refractometer, and the average value was calculated.

[0028] (4) Stone cell content The determination was performed using the freezing method. The mixed pear pulp was frozen at -20°C for 24 hours, then juiced in a juicer. Water was added and the mixture was allowed to stand. The upper suspension was poured off and the mixture was rinsed at least 4 times. The lower layer of stone cells was collected by filtering through filter paper and then dried in an oven at 70°C for 3 hours. The dried stone cells were weighed.

[0029] (5) Soluble sugar content The anthrone-sulfuric acid colorimetric method was used for determination. A glucose solution was prepared, and a standard curve was plotted. Soluble sugars were extracted from pear samples treated with different methods, and their absorbance was measured at 630 nm. The amount of sugar in the sample (μg) was determined using the standard curve, and the soluble sugar content in the sample was calculated using the following formula:

[0030] Where: C - the amount of glucose (μg) in the sample test tube obtained from the standard curve; n - dilution factor; 1000 - Conversion factor; V t - Total volume of sample extract (mL); V s - Take the sample liquid volume (mL) during the measurement. W - Fresh weight of the sample (g).

[0031] (6) Titratable acid content: determined by acid-base neutralization titration. The NaOH titration method was used. 5g of ground fruit was weighed, washed into a test tube with a small amount of distilled water, and immersed in a boiling water bath for 40 minutes. After cooling, the solution was filtered and diluted to 100mL. 20mL of the test solution was placed in an Erlenmeyer flask, 2 drops of 1% phenolphthalein were added, and titrated with 0.05mol / L NaOH standard solution until the light pink color persisted.

[0032]

[0033] Where: C-NaOH standard solution molar concentration; V1 - Volume of NaOH consumed during titration (mL); V0 - Volume of titrated sample liquid drawn out (mL); m - Sample mass (g); K is the coefficient for converting a certain acid in grams.

[0034] (7) Vitamin C content: determined by the 2,6-dichlorophenol titration method. The calculation formula for the determination result is as follows:

[0035] Where: V1 - the volume of dye consumed in the sample titration (mL); V0 - Volume of dye consumed in blank titration (mL); C - Amount of ascorbic acid per 1 mL (mg); V S - The volume (mL) of sample solution taken during titration. Example 1

[0036] This embodiment provides a composite decalyxing agent for improving the quality of Korla fragrant pears, obtained by mixing methyl jasmonate, naphthyl o-carbamoylbenzoic acid and 5-ALA, and its preparation method. The preparation method includes the following steps.

[0037] ① Dissolve 15 mg of naphthyl o-carbamoylbenzoic acid, 15 mg of 5-ALA, and 1 g of zein powder in 50 mL of 70% (v / v) ethanol solution. Stir magnetically for 1 h at 1000 r / min to ensure complete dissolution and obtain a mixed zein solution.

[0038] ② Dissolve 1g of chitosan in 50mL of 1% acetic acid aqueous solution to obtain a chitosan solution. Add the mixed zein solution dropwise to an equal volume of chitosan solution using a peristaltic pump and continue magnetic stirring for 1h to obtain a dispersion.

[0039] ③ The ethanol was removed under vacuum (0.1 MPa) at 35℃, and then the dispersion was brought to a final volume of 90 mL with deionized water to obtain a mixed zein-chitosan solution.

[0040] ④ Dissolve 15 mg of methyl jasmonate in 10 mL of soybean oil and stir thoroughly to obtain an oil solution of methyl jasmonate.

[0041] ⑤ Add 10 mL of methyl jasmonate oil solution to 90 mL of the mixed zein-chitosan solution prepared in step ③, and emulsify at 10000 r / min for 3 min to obtain a Pickering emulsion with an oil volume fraction of 10%, which is a composite decalyxing agent for improving the quality of Korla fragrant pear.

[0042] In this compound decalyxing agent, methyl jasmonate is 150 ppm, naphthyl o-carbamoylbenzoic acid is 150 ppm, and 5-ALA is 150 ppm.

[0043] Similarly, adjusting the concentrations of methyl jasmonate, naphthyl-o-carbamoylbenzoic acid, and 5-ALA can yield composite decalyxing agents of other concentrations.

[0044] Group Treatment method (ppm) A 250 MeJA, 50 5-ALA, 150 NPA B 150 MeJA, 50 5-ALA, 250 NPA C 150MeJA, 150 5-ALA, 150NPA D 50 MeJA, 250 5-ALA, 150 NPA E 150 NPA F 150MeJA G 150 5-ALA H CK (empty-loaded zein-chitosan-soybean oil emulsion) Spraying Experiment: The experiment in this embodiment was conducted at the Xiyu Xiangfei Pear production base in Xiaolangan Village, Awati Township, Korla City. The rows were spaced 3m x 4m apart. The trees were 21 years old, vigorous, and uniformly growing Korla pears. 3-5 pear trees were randomly selected for each group, and each tree was sprayed with one treatment. For each tree, spraying was performed on large, vigorous branches facing southwest with good sunlight, free from pests and diseases, and exhibiting uniform growth. Spraying Time: Spraying was performed once on a sunny, windless morning between 9:00-11:00 AM or after 4:00 PM, during the inflorescence bud stage (3-5 days before flowering), ensuring even coverage of the inflorescence.

[0045] Application method: Use a manual sprayer, keeping the nozzle 15-20 cm away from the inflorescence. Spray evenly on each branch and inflorescence, ensuring the surface is moist but not dripping. Avoid missing or overlapping sprays. Depending on the thickness of the branch, the spraying amount is 2-20 mL per branch.

[0046] Control group treatment: The CK group was sprayed with an equal amount of water, and the spraying time and method were exactly the same as those of the pesticide group.

[0047] Field management: If it rains within one week after spraying, a second spray is required (the concentration and method of the second spray should be the same as the first spray); during the trial period, the field management measures (watering, fertilization, pest and disease control, etc.) of each group should be kept consistent.

[0048] The experiment involved two sprayings, one every 15 days. The first spraying was carried out on July 3, 2025 (during the fruit enlargement period), and the second spraying was carried out on July 18, 2025 (during the fruit enlargement period).

[0049] Sample Collection: Fruits for the experiment were collected on September 15, 2025 (fruit ripening stage). For each treatment, fruits from the outer periphery of the canopy with good light conditions, a height of 1-1.5m, uniform size, free from pests and diseases, and with a regular shape were collected as experimental samples. A total of 18 fruits were collected for each treatment. Among them, 9 fruits were used to determine the appearance quality, including longitudinal diameter, transverse diameter, fruit shape index, and fruit weight. The remaining 9 fruits were used to determine the internal quality, including firmness and soluble solids.

[0050] The fruit harvest season begins on September 15, 2025. Considering the differences between fruits, nine fruits were selected for measurement and the average value was taken. The specific longitudinal diameter, transverse diameter, fruit shape index, and single fruit weight are shown in the table below.

[0051] deal with Longitudinal diameter (mm) transverse diameter (mm) Fruit shape index Single fruit weight (g) A: 250 MeJA, 50 5-ALA, 150 NPA 65.39±2.15 b 63.79±2.84 bc 1.03±0.06 ab 154.55±9.79 bc B: 150 MeJA, 50 5-ALA, 250 NPA 64.78±2.59 bc 65.86±1.76 ab 0.99±0.06 b 173.17±14.27 ab C:150MeJA,150 5-ALA,150NPA 66.52±1.56 b 65.21±0.99 abc 1.02±0.03 ab 167.49±7.38 ab D: 50 MeJA, 250 5-ALA, 150 NPA 72.22±1.37 a 67.25±0.46 a 1.08±0.015 a 184.77±19.30 a E:150NPA 65.66±1.49 b 63.70±1.77 bc 1.03±0.04 ab 159.38±9.14 bc F:150MeJA 65.08±1.19 bc 64.49±1.08 abc 1.01±0.02 b 172.25±1.58 ab G:150 5-ALA 63.36±1.450 bc 64.05±1.91 bc 0.99±0.03 b 157.36±13.56 bc H:CK 61.85±3.02 c 62.31±2.39 c 0.99±0.02 b 142.63±16.46 c Similarly, nine fruits were selected for testing, and the average value was taken. The results for firmness, soluble solids, stone cell content, vitamin C content, soluble sugar content, and titratable acidity are shown in the table below.

[0052] deal with <![CDATA[Hardness (kg / cm 2 )]]> Soluble solids (%) Stone cell content (g / 100g) Vitamin C (mg / 100g) Soluble sugars (%) Titratable acid (g / kg) A: 250 MeJA, 50 5-ALA, 150 NPA 7.12±0.21 bc 12.60±0.39 cd 0.21±0.06 a 3.21±0.16 a 8.98±0.19 ab 0.34±0.12 a B: 150 MeJA, 50 5-ALA, 250 NPA 7.24±0.65 bc 12.28±0.47 de 0.21±0.06 a 2.86±0.17 bc 8.60±0.44 bc 0.34±0.03 a C:150MeJA,150 5-ALA,150NPA 6.53±0.06 c 13.04±0.64 abc 0.21±0.02 a 3.22±0.07 a 9.13±0.28 ab 0.32±0.05 a D: 50 MeJA, 250 5-ALA, 150 NPA 6.63±0.04 c 13.48±0.32 a 0.21±0.05 a 3.28±0.16 a 9.68±0.06 a 0.33±0.02 a E:150NPA 8.42±0.40 a 11.72±0.21 e 0.21±0.01 a 3.11±0.08 ab 7.90±1.08 cd 0.36±0.05 a F:150MeJA 7.37±0.51 b 12.18±0.22 de 0.23±0.01 a 3.10±0.19 ab 8.77±0.47 b 0.32±0.03 a G:150 5-ALA 7.20±0.58 bc 13.28±0.40 ab 0.22±0.01 a 3.02±0.03 abc 9.26±0.63 ab 0.33±0.03 a H:CK 8.63±0.48 a 12.73±0.25 bcd 0.23±0.02 a 2.73±0.37 c 7.29±0.064 d 0.36±0.05 a Similarly, the calyx defoliation rate and fruit drop rate after being sprayed with different solutions were measured, and the specific results are shown in the table below.

[0053] deal with Calyx deciduous rate Fruit drop rate A: 250 MeJA, 50 5-ALA, 150 NPA 91.27% 93.25% B: 150 MeJA, 50 5-ALA, 250 NPA 95.47% 98.94% C:150MeJA,150 5-ALA,150NPA 100% 97.36% D: 50 MeJA, 250 5-ALA, 150 NPA 94.51% 98.36% E:150NPA 49.01% 69.59% F:150MeJA 98.41% 89.31% G:150 5-ALA 92.91% 85.25% H:CK 79.83% 85.69% The fruit quality of Korla fragrant pears under different treatments was comprehensively evaluated based on the eigenvectors calculated from the component matrix and contribution rate. The methods and results are as follows.

[0054] Principal component analysis was performed on 10 quality traits of Korla fragrant pear. The number of principal components was determined according to the principle that the eigenvalue is greater than 1.0, and a linear relationship between the principal components and the quality of Korla fragrant pear was constructed. Yn=c1X1+c2X2+…+cnXn. (1) In the formula: Yn is the score of the nth principal component, c1~c10 represent the eigenvectors of the fruit longitudinal diameter, fruit transverse diameter, fruit shape index, single fruit weight, fruit firmness, soluble solids content, stone cell content, vitamin C content, soluble sugar content, and titratable acid content on the principal components, respectively, and X1~X10 represent the standardized values ​​of the fruit longitudinal diameter, fruit transverse diameter, fruit shape index, single fruit weight, fruit firmness, soluble solids content, stone cell content, vitamin C content, soluble sugar content, and titratable acid content after being analyzed by the software.

[0055] The overall score is: Y=λ1Y1+λ2Y2+…+λnYn. (2) In the formula: λ1~λn represent the variance contribution rates corresponding to the 1st to nth principal components.

[0056] The data analyzed does not include the sepal deciduous rate; the specific results are shown in the table below.

[0057] Principal component Eigenvalue Variance contribution rate Cumulative contribution rate 1 6.214 62.141 62.141 2 1.576 15.759 77.899 Models were constructed for the two extracted principal components, as follows: F1=0.339×x1+0.357×x2+0.359×x3+0.293×x4+0.205×x5-0.358×x6+0.227×x7+0.367×x8-0.283×x9+0.326×x10; F2=0.049×x1+0.292×x2+0.043×x3+0.424×x4-0.390×x5+0.288×x6+0.411×x7-0.238×x8+0.492×x9+0.170×x10; F = F1 × 0.6214 + F2 × 0.1576.

[0058] Treatment PC1 (F1) PC2 (F2) Comprehensive score Comprehensive ranking A: 250 MeJA, 50 5-ALA, 150 NPA 0.26 0.43 0.23 3 B: 150 MeJA, 50 5-ALA, 250 NPA -0.17 0.01 -0.11 4 C:150MeJA,150 5-ALA,150NPA 1.84 -0.68 1.04 2 D: 50 MeJA, 250 5-ALA, 150 NPA 4.31 0.77 2.8 1 E:150NPA -1.56 2.41 -0.59 7 F:150MeJA -0.04 -0.97 -0.18 5 G:150 5-ALA -0.29 -1.73 -0.45 6 H:CK -4.35 -0.25 -2.74 8 As shown in the table above, the indicators excluding the calyx defoliation rate were standardized, simplifying the 10 indicators into two principal components with eigenvalues ​​of 6.214 and 1.576, respectively. The first principal component mainly includes single fruit weight, longitudinal and transverse diameters, fruit shape index, soluble solids, stone cell content, soluble sugar, vitamin C, and calyx defoliation rate, which can represent the quality characteristics of the fruit. The second principal component mainly includes firmness and titratable acid content, which can represent the taste and flavor characteristics of the fruit.

[0059] The final ranking is shown in the table above. The treatment with the highest overall evaluation is treatment group D (50 MeJA, 250 5-ALA, 150 NPA), ranked as follows: D (50 MeJA, 250 5-ALA, 150 NPA) > C (150 MeJA, 150 5-ALA, 150 NPA) > A (250 MeJA, 50 5-ALA, 150 NPA) > B (150 MeJA, 50 5-ALA, 250 NPA) > F (150 MeJA) > G (150 5-ALA) > E (150 NPA) > H (CK).

[0060] Secondly, the data analyzed does not include the calyx deciduous rate; the specific results are shown in the table below.

[0061] Principal component Eigenvalue Variance contribution rate Cumulative contribution rate / % 1 6.505 59.138 59.138 2 2.168 19.706 78.844 Models were constructed for the two extracted principal components, as follows: F1=0.329×x1+0.334×x2+0.350×x3+0.266×x4+0.215×x5-0.363×x6+0.203×x7+0.365×x8-0.296×x9+0.306×x10+0.227×x11; F2=0.081×x1+0.299×x2+0.073×x3+0.408×x4-0.285×x5+0.196×x6+0.378×x7-0.129×x8+0.365×x9+0.223×x10-0.520×x11; F = F1 × 0.6214 + F2 × 0.1576.

[0062] Table 8: Quality Factor Scores and Rankings of Korla Fragrant Pears under Different Treatments Treatment PC1 (F1) PC2 (F2) Comprehensive score Comprehensive ranking A: 250 MeJA, 50 5-ALA, 150 NPA 0.28 0.34 0.23 3 B: 150 MeJA, 50 5-ALA, 250 NPA -0.06 -0.32 -0.1 4 C:150MeJA,150 5-ALA,150NPA 1.99 -0.65 1.05 2 D: 50 MeJA, 250 5-ALA, 150 NPA 4.26 1.1 2.73 1 E:150NPA -2.15 2.98 -0.68 7 F:150MeJA 0.15 -1.14 -0.14 5 G:150 5-ALA -0.14 -1.64 -0.41 6 H:CK -4.32 -0.66 -2.68 8 As shown in the table above, the calyx defoliation rate and fruit quality indicators were standardized together, simplifying the 11 indicators into two principal components with eigenvalues ​​of 6.505 and 2.168, respectively. A comprehensive evaluation was then performed on these two principal components. The first principal component mainly includes single fruit weight, longitudinal and transverse diameters, fruit shape index, soluble solids, soluble sugar, vitamin C, and calyx defoliation rate, representing the fruit's quality characteristics. The second principal component mainly includes firmness, stone cell content, and titratable acid content, representing the fruit's taste and flavor characteristics.

[0063] The final ranking is shown in the table above. The treatment with the highest overall evaluation is treatment group D (50 MeJA, 250 5-ALA, 150 NPA), ranked as follows: D (50 MeJA, 250 5-ALA, 150 NPA) > C (150 MeJA, 150 5-ALA, 150 NPA) > A (250 MeJA, 50 5-ALA, 150 NPA) > B (150 MeJA, 50 5-ALA, 250 NPA) > F (150 MeJA) > G (150 5-ALA) > E (150 NPA) > H (CK).

[0064] This embodiment provides a composite decalyxing agent for improving the quality of Korla fragrant pears, obtained by mixing methyl jasmonate, naphthyl o-carbamoylbenzoic acid and 5-ALA, and its preparation method. The preparation method includes the following steps.

[0065] ① Dissolve 5 mg of naphthyl o-carbamoylbenzoic acid, 25 mg of 5-ALA, and 0.5 g of zein powder in 50 mL of 65% (v / v) ethanol solution. Stir magnetically for 0.5 minutes at 200 r / min to ensure complete dissolution and obtain a mixed zein solution.

[0066] ② Dissolve 0.5g of chitosan in 50mL of 2% acetic acid aqueous solution to obtain chitosan solution. Add the mixed zein solution dropwise to an equal volume of chitosan solution using a peristaltic pump and continue magnetic stirring for 0.5h to obtain dispersion.

[0067] ③ The ethanol was removed under vacuum (0.01 MPa) at 30℃, and then the dispersion was brought to a final volume of 80 mL with deionized water to obtain a mixed zein-chitosan solution.

[0068] ④ Dissolve 5 mg of methyl jasmonate in 20 mL of soybean oil and stir thoroughly to obtain an oil solution of methyl jasmonate.

[0069] ⑤ Add 20 mL of methyl jasmonate oil solution to 80 mL of the mixed zein-chitosan solution prepared in step ③, and emulsify at 5000 r / min for 1 min to obtain a Pickering emulsion with an oil volume fraction of 20%, which is a composite decalyxing agent for improving the quality of Korla fragrant pear. Example 3

[0070] This embodiment provides a composite decalyxing agent for improving the quality of Korla fragrant pears, obtained by mixing methyl jasmonate, naphthyl o-carbamoylbenzoic acid and 5-ALA, and its preparation method. The preparation method includes the following steps.

[0071] ① Dissolve 25 mg of naphthyl o-carbamoylbenzoic acid, 5 mg of 5-ALA, and 2 g of zein powder in 50 mL of 75% (v / v) ethanol solution. Stir magnetically for 4 h at 2000 r / min to ensure complete dissolution and obtain a mixed zein solution.

[0072] ② Dissolve 2g of chitosan in 50mL of 4% acetic acid aqueous solution to obtain chitosan solution. Add the mixed zein solution dropwise to an equal volume of chitosan solution using a peristaltic pump and continue magnetic stirring for 4h to obtain dispersion.

[0073] ③ The ethanol was removed under vacuum (0.2 MPa) at 38℃, and then the dispersion was brought to a final volume of 85 mL with deionized water to obtain a mixed zein-chitosan solution.

[0074] ④ Dissolve 5-25 mg of methyl jasmonate in 15 mL of soybean oil and stir thoroughly to obtain an oil solution of methyl jasmonate.

[0075] ⑤ Add 15 mL of methyl jasmonate oil solution to 85 mL of the mixed zein-chitosan solution prepared in step ③, and emulsify at 15000 r / min for 10 min to obtain a Pickering emulsion with an oil volume fraction of 15%, which is a composite decalyxing agent for improving the quality of Korla fragrant pear.

Claims

1. A calyx-removing agent for improving the quality of Korla fragrant pears, characterized in that, The decalyxing agent is a zein-chitosan-soybean oil Pickering emulsion, which contains 50-250 ppm of methyl jasmonic acid, 50-250 ppm of naphthyl-o-carbamoylbenzoic acid, and 50-250 ppm of 5-ALA. Methyl jasmonic acid is dissolved in soybean oil, while naphthyl-o-carbamoylbenzoic acid and 5-ALA are dissolved in the zein-chitosan solution.

2. The calyx-removing agent for improving the quality of Korla fragrant pears according to claim 1, characterized in that, The volume ratio of the zein-chitosan solution to soybean oil is 1:9 to 2:

8.

3. A method for preparing a calyx-removing agent to improve the quality of Korla fragrant pears, characterized in that, Includes the following steps: ① Dissolve naphthyl o-carbamoylbenzoic acid, 5-ALA, and zein powder in an ethanol solution and stir until fully dissolved to obtain a mixed zein solution; ② Dissolve chitosan in an aqueous acetic acid solution to obtain a chitosan solution. Add the mixed zein solution dropwise to an equal volume of chitosan solution and continue stirring. Then remove ethanol by vacuum distillation to obtain a mixed zein-chitosan solution. ③ Dissolve methyl jasmonate in soybean oil and stir thoroughly to obtain an oil solution of methyl jasmonate; ④ Mix the oil solution of methyl jasmonate and the mixed zein-chitosan solution at a volume ratio of 1:9 to 2:8, and emulsify at high speed to obtain a composite decalyx agent that improves the quality of Korla fragrant pears. The final concentrations of methyl jasmonate, naphthyl-o-carbamoylbenzoic acid, and 5-ALA in the system were 50-250 ppm.

4. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The final concentration of the zein is 0.05~0.2 g / L.

5. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The ethanol solution is specifically an aqueous solution of ethanol with a volume fraction of 65-75%.

6. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The method for removing ethanol by vacuum distillation involves evaporating ethanol at a vacuum of 30-38°C and 0.01-0.2 MPa.

7. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The stirring is specifically magnetic stirring at 200~2000 r / min for 0.5~4h.

8. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The volume fraction of the acetic acid aqueous solution is 1-4%.

9. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pears according to claim 3, characterized in that, The final concentration of the chitosan is 0.05~0.2 g / L.

10. The method for preparing the calyx-removing agent for improving the quality of Korla fragrant pear according to claim 3, characterized in that, The high-speed emulsification is carried out at 5000~15000 r / min for 1~10 min.

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