Method for improving quality of korla fragrant pear

Abstract

The two methods for improving the quality of Korla fragrant pear of the present application belong to the technical field of fruit tree planting, the first method is to spray a polypeptide EGAK solution on the branches of Korla fragrant pear during the fruit expansion period each year, the second method is to spray a mixed solution of polypeptide EGAK and 5-ALA on the branches of Korla fragrant pear during the fruit expansion period each year. The present application simultaneously provides two solutions for improving the quality of Korla fragrant pear, the first solution is a polypeptide EGAK solution with a concentration of 50-500 ppm, and the second solution is a mixed solution of polypeptide EGAK and 5-ALA with a final concentration of 50-500 ppm. The method of the present application is simple and low in cost, and can effectively improve the quality of Korla fragrant pear, reduce the acidity, and increase the content of vitamin C, and has high economic value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fruit tree planting, and particularly relates to a method for improving the quality of Korla fragrant pear. BACKGROUND

[0002] Korla fragrant pear belongs to the Rosaceae pear system in Xinjiang, and is one of the fruit crops with important economic value in Xinjiang. Its pleasant flavor and rich nutritional components make it popular in the market. The main characteristics of Korla fragrant pear are its unique aroma and crisp taste. The overall flavor is composed of sugar, acid and aroma, and the overall taste is composed of hardness, stone cells and other qualities. Both of them are important factors for fresh eating and processing of fruit. In addition, there are "male pears" (calyx fruits) and "female pears" (calyx-free fruits) in Korla fragrant pear fruits. Most studies believe that calyx-free fruits have better quality, stronger aroma and stronger market competitiveness. However, there are few studies on volatile metabolites of Korla fragrant pear. According to the previous study of the research group on volatile metabolites of Korla fragrant pear, exogenous spraying of 5-aminolevulinic acid (5-ALA) has a certain influence on the quality of Korla fragrant pear.

[0003] 5-ALA is a highly efficient plant growth regulator and an important biosynthetic precursor of tetrapyrrole compounds, and is widely used in horticulture. Studies have shown that the application of 5-ALA can improve fruit quality and yield. For example, exogenous 5-ALA increased the content of soluble solids, soluble sugars, titratable acids, vitamin C and soluble proteins in 'Fengshui' pear fruits, and increased the weight of single fruit. Spraying 5-ALA on the surface of the fruit, or irrigating 5-ALA in the rhizosphere, can significantly promote fruit coloring, nutritional quality and flavor quality, and can promote the post-ripening of tomato fruits. In addition, 5-ALA can also increase the aroma content of fruits. Studies have found that 5-ALA treatment can increase the content of ethyl acetate in fruits, produce geranylacetone, and thus make the aroma of grapes more abundant. Exogenous application of 5-ALA can significantly increase the content of volatile substances in tomato fruits, produce carotenoid derivatives 6-methyl-5-heptene-2-ketone, geranylacetone, b-ionone and ionone, which give tomato fruits flavor and aromatic flavor. These results show that 5-ALA has the potential to promote the increase of fruit volatile substances.

[0004] Polypeptides are short-chain molecules composed of multiple amino acids connected by peptide bonds, and are the basic units of proteins. They also independently participate in various important functions in living organisms. Polypeptides can improve the quality of crops and increase the nutritional value of crops. By optimizing the growth process of plants, polypeptides can make crops accumulate more nutrients during growth, thereby improving the overall quality of crops. However, not all polypeptides have a promoting effect on crop fruits.

[0005] The research group found that the exogenous spraying of 5-ALA indeed has a certain promoting effect on the quality of Korla fragrant pear, but the effect is not too good, therefore, in order to further improve the quality of Korla fragrant pear, the inventors further study the planting technology of Korla fragrant pear to provide valuable theoretical basis for the application in the agricultural field. SUMMARY

[0006] In order to improve the quality, taste and related physical and chemical indexes of Korla fragrant pear, on the basis of previous research, the present application provides two methods for improving the quality of Korla fragrant pear, as follows.

[0007] One method for improving the quality of Korla fragrant pear is to spray a polypeptide EGAK solution on the branches of Korla fragrant pear during the fruit swelling period of each year.

[0008] The spraying concentration of the polypeptide EGAK solution is 50-500 ppm.

[0009] The spraying amount of the polypeptide EGAK is 2-20 mL / branch.

[0010] The second method for improving the quality of Korla fragrant pear is to spray a mixed solution of polypeptide EGAK and 5-ALA on the branches of Korla fragrant pear during the fruit swelling period of each year.

[0011] The spraying concentration of the polypeptide EGAK solution is 50-200 ppm.

[0012] The spraying concentration of the 5-ALA solution is 200 ppm.

[0013] Obviously, the polypeptide EGAK is sprayed on the branches of Korla fragrant pear to improve the quality of Korla fragrant pear.

[0014] The present application also provides a solution for improving the quality of Korla fragrant pear, which is a polypeptide EGAK solution with a concentration of 50-500 ppm.

[0015] The second mixed solution for improving the quality of Korla fragrant pear is a mixed solution of polypeptide EGAK and 5-ALA with a final concentration of 50-500 ppm.

[0016] The concentration of the 5-ALA is 200 ppm.

[0017] Advantages

[0018] The current research results are that some polypeptide substances can improve the quality of crops and increase the nutritional value of crops. By optimizing the growth process of plants, polypeptides can make crops accumulate more nutrients during growth, thereby improving the overall quality of crops. According to Xiao's master's thesis "Effect of Polypeptide Spraying on Yield and Quality of Fresh Table Grapes", polypeptide spraying alone or in combination with zinc can increase the yield and quality of grapes. The yield of grapes sprayed with polypeptide and zinc is increased by 10.99% compared with zinc alone, and the soluble sugar content in the fruit is significantly increased. The inventor sprayed polypeptide on Korla fragrant pears from 2022 to 2023, but the results showed that the purchased polypeptide had no significant effect on the fruit quality of Korla fragrant pears. Therefore, the inventor analyzed the acid metabolism pathway of sweet fragrant pears and obtained two polypeptides, polypeptide EGAK and polypeptide EGKI. The results showed that polypeptide EGAK cannot increase the soluble sugar content of the fruit, but can reduce the acidity of the fruit, improve the taste of Korla fragrant pears, and improve the hardness, taste and quality of Korla fragrant pears when sprayed with 5-ALA.

[0019] The inventor can see from the comparative experiments that the effects of polypeptide EGAK and polypeptide EGKI on the quality of Korla fragrant pear fruit are quite different. It is possible that polypeptide EGAK directly regulates the acid metabolism and sugar metabolism inside the fruit.

[0020] As can be seen from the results of Examples 1 and 2, when polypeptide EGAK is sprayed alone, the fruit quality is best when the spraying concentration is 300-400 ppm. Of course, 200 and 500 ppm also have a certain effect on the fruit. At the same time, if 5-ALA of 200 ppm is mixed and sprayed, only 50-200 ppm of polypeptide EGAK is needed to achieve the same effect.

[0021] In summary, spraying polypeptide EGAK alone and mixing polypeptide EGAK and 5-ALA can reduce the acidity of Korla fragrant pears and increase the content of vitamin C, while the effect of using 5-ALA alone is not good. It can be seen that 5-ALA plays a promoting synergistic role, reducing the amount of EGAK.

[0022] The present application has low cost, fewer spraying times, and is suitable for various pear orchards. After spraying, the acidity of Korla fragrant pears is significantly reduced, the content of vitamin C is significantly increased, and the taste is obviously improved, which has high economic value. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The chemical structure of polypeptide EGAK is shown in the figure.

[0024] Figure 2Chemical structure of polypeptide EGKI. DETAILED DESCRIPTION

[0025] The application is described in detail below in conjunction with examples. All methods and techniques, unless otherwise specified, are conventional methods and techniques.

[0026] 5-ALA (99%) was purchased from Shanghai Yuan Ye Biotechnology Co., Ltd. (product number S30944, only available for scientific research). Polypeptide EGAK was synthesized by connecting glutamic acid, glycine, alanine and lysine in sequence through peptide bonds, and polypeptide EGKI was synthesized by connecting glutamic acid, glycine, lysine and isoleucine in sequence through peptide bonds. The polypeptide was prepared by QYAOBIO (China Peptides Co., Ltd.).

[0027] Experimental method

[0028] (1) Single fruit weight, length and width

[0029] Five fruits were randomly selected from each of the four directions of each tree, i.e. 20 fruits per tree, and 60 fruits in total for each treatment. The average weight of each fruit was calculated using a one-hundredth electronic balance, and the average length and width were calculated using a vernier caliper. Fruit shape index: the ratio of the length to the width of the fruit.

[0030] (2) Hardness

[0031] A GY-1 hardness tester was used. Fifteen fruits were randomly selected from each treatment, and five of them were randomly selected as a group. The hardness of each pear was measured at four different directions using a GY-1 hardness tester, and the average value was calculated.

[0032] (3) Soluble solids

[0033] A digital refractometer was used. Fifteen fruits were randomly selected from each treatment, and five of them were randomly selected as a group. The soluble solids content of each pear was measured at four different directions using a digital refractometer, and the average value was calculated.

[0034] (4) Stone cell content

[0035] A frozen method was used. After the mixed pear pulp was frozen at -20°C for 24 hours, it was stirred into juice in a juicer. Water was added and the upper layer of suspended matter was poured out after standing. The lower layer of stone cells was collected by filtering paper and placed in an oven at 70°C for 3 hours. The dried stone cells were weighed.

[0036] (5) Soluble sugar content

[0037] Anthrone-sulfuric acid colorimetric method. Prepare glucose solution, draw standard curve. Extract soluble sugar in different treatment pear samples, measure its absorbance value at 630 nm, find the amount of sugar in the sample (μg) through the standard curve, calculate the soluble sugar content in the sample according to the following formula:

[0038]

[0039] In the formula: C-the amount of glucose contained in the sample determination tube (μg) found by standard curve;

[0040] n-dilution multiple;

[0041] 1000-conversion coefficient;

[0042] V t -the total volume of sample extraction solution (mL);

[0043] V s -the volume of sample liquid taken when measuring (mL);

[0044] W-fresh weight of sample (g).

[0045] (6) Titration acid content: determined by acid-base neutralization titration method. NaOH titration method was used for determination, 5g of ground fruit was taken, washed into a test tube with a small amount of distilled water, immersed in a boiling water bath for 40min, after taking out and cooling, filtered and diluted to 100mL. Take 20mL of the measured liquid into a triangular flask, add 2 drops of 1% phenolphthalein, titrate with 0.05mol / L NaOH standard solution until the color is light pink and does not fade.

[0046]

[0047] In the formula: C-molar concentration of NaOH standard solution;

[0048] V1-volume of NaOH consumed during titration (mL);

[0049] V0-volume of titration sample liquid taken (mL);

[0050] m-mass of sample (g);

[0051] K-conversion coefficient to grams of a certain acid.

[0052] (7) Vitamin C content: determined by 2-6 dichlorophenol titration method. 2,6-dichlorophenol titration method was used, and the calculation formula of the determination result was:

[0053]

[0054] In the formula: V1-volume of dye consumed by sample titration (mL);

[0055] V0 - Volume of dye consumed in blank titration (mL);

[0056] C - Amount of ascorbic acid (mg) in 1 mL;

[0057] V S - Volume of sample solution taken at the time of titration (mL).

[0058] The test was carried out in the Xiyu Xiangfei pear production base of Xiaolan Village, Awati Township, Korla City, with a row spacing of 3m*4m, a tree age of 20 years, a vigorous tree vigor, and a consistent growth of Korla pear trees. 3-5 pear trees were randomly selected for treatment, and each tree was sprayed with one treatment. The test trees were sprayed in the southwest with good sunlight, no pests and diseases, and consistent growth and vigorous growth of the branches. The spraying time was selected before 12 o'clock in the morning on a sunny and windy day, and the spraying site was fully wet and had liquid droplets. According to the different thickness of the branches, the spraying amount was 2-20 mL / branch.

[0059] The test was sprayed twice, with a 15-day interval. The first spraying was carried out on July 4, 2024 (fruit expansion period), and the second spraying was carried out on July 19, 2024 (fruit expansion period).

[0060] Sample collection: On September 12, 2024 (fruit ripening period), the test samples were collected, and 18 fruits were collected for each treatment as test samples. Among them, 9 fruits were used as samples for determining the appearance quality, including longitudinal diameter, transverse diameter, fruit shape index and fruit weight, and 9 fruits were used as samples for determining the internal quality, including hardness and soluble solids.

[0061] Example 1

[0062] This example provides a method for improving the quality of Korla pears, which is to spray polypeptide EGAK alone. The specific experimental method is as follows.

[0063] The polypeptide EGAK with a concentration of 200, 300, 400 and 500 ppm was set for spraying. The specific experiment is shown in the following table.

[0064] Period Group 1 Group 2 Group 3 Group 4 Group 5 July 4 200 300 400 500 Equal amount of water (CK) July 15 200 300 400 500 Equal amount of water (CK)

[0065] On September 12, 2024, the fruit harvest period was entered, and considering the differences between fruits, 9 fruits were selected to determine the average value. The specific fruit shape index, single fruit weight, soluble solids and hardness are shown in the following table.

[0066] Group Fruit shape index (%) Single fruit weight (g) Soluble solids (%) Hardness (kg / cm 2 ) Group 1 1.04±0.02 132.52±2.89 11.12±0.17 5.80±0.11 Group 2 1.06±0.03 136.72±4.57 12.64±0.26 5.93±0.18 Group 3 1.04±0.02 135.22±2.75 12.30±0.29 6.07±0.16 Group 4 1.04±0.02 137.36±4.30 11.34±0.12 5.76±0.18 Group 5 1.03±0.02 120.97±4.96 10.96±0.35 6.41±0.14

[0067] As can be seen from the table above, after treatment with polypeptide EGAK, the weight of each fruit increased, the soluble solids content increased, and the average firmness of the fruit decreased, but the improvement effect was significant. Judging from the average results, the fruit shape index had little effect. This shows that spraying polypeptide EGAK alone has no significant effect on the appearance and weight of the fruit.

[0068] The specific ratios of soluble sugar, stone cells, Vc, titratable acid and solid acid are shown in the following table.

[0069]

[0070] As can be seen from the above table, after treatment with polypeptide EGAK, the vitamin C content increased significantly, while the titratable acid content decreased, the solid-acid ratio increased significantly, the stone cell content did not change significantly, the soluble sugar content decreased, the sweetness did not decrease, and the sourness decreased significantly. This shows that spraying polypeptide EGAK can increase the vitamin C content.

[0071] Example 2

[0072] This example provides a method for improving the quality of Korla fragrant pears. The specific experimental method is as follows.

[0073] The concentrations of 50, 100, 150, and 200 ppm of the polypeptide EGAK were mixed with 200 ppm of 5-ALA (5-aminolevulinic acid) for spraying. 200 ppm of 5-ALA was the optimal spraying concentration obtained in the previous experiments. The specific experiments are shown in the table below.

[0074]

[0075] The fruit harvest season began on September 12, 2024. Taking into account the differences between fruits, 9 fruits were selected for measurement and the average value was taken. The specific fruit shape index, single fruit weight, soluble solids and hardness are shown in the following table.

[0076] Group Fruit shape index (%) Single fruit weight (g) Soluble solids (%) Hardness (kg / cm 2 ) Group 1 1.04±0.01 132.74±2.79 12.12±0.42 6.68±0.20 Group 2 1.06±0.03 132.30±1.67 12.07±0.19 6.77±0.26 Group 3 1.05±0.02 133.54±2.22 12.14±0.32 6.65±0.09 Group 4 1.06±0.03 133.15±2.31 12.46±0.15 6.97±0.14 Group 5 1.04±0.02 131.44±4.35 11.29±0.43 6.60±0.16 Group 6 1.05±0.02 121.41±1.47 10.94±0.18 6.50±0.15 Group 7 1.04±0.01 131.83±1.16 11.06±0.33 6.13±0.13

[0077] As can be seen from the above table, after spraying the polypeptide EGAK and 5-ALA, the weight of single fruit increased, but the increase was not obvious, the soluble solid content increased, and the average hardness of the fruit increased. Judging from the average results, there was little effect on the fruit shape index.

[0078] The specific ratios of soluble sugar, stone cells, Vc, titratable acid and solid acid are shown in the following table.

[0079]

[0080] From the above table, after spraying polypeptide EGAK and 5-ALA, the content of vitamin C increased significantly, the content of titratable acid decreased, and the ratio of solid to acid increased significantly. Under the condition of the increase of vitamin C content in fruit, the total titratable acid also decreased, indicating that the acidic components in the fruit decreased. It may be that after mixed spraying, the main acid-producing substances such as citric acid and tartaric acid are decomposed, which makes the acidity of the fruit decrease, while the stone cell content does not change, but the soluble sugar content decreases. From the taste results, there is no obvious difference in sweetness between the control group and the polypeptide EGAK and 5-ALA mixed spraying group. Analysis shows that the mixed spraying of polypeptide EGAK and 5-ALA mainly accelerates the acid metabolism and sugar metabolism of the fruit, and since the sweetness of Korla fragrant pear is relatively large, the overall taste of Korla fragrant pear is improved.

Claims

1. A method for improving the quality of Korla fragrant pear, characterized in that: The method for improving the quality of Korla fragrant pear specifically comprises spraying a polypeptide EGAK solution on the branches of Korla fragrant pear during the fruit expansion period each year. The polypeptide EGAK is synthesized by sequentially connecting the peptide bonds of glutamic acid, glycine, alanine and lysine. The spraying concentration of the polypeptide EGAK solution is 200-500 ppm.

2. The method for improving the quality of Korla fragrant pear according to claim 1, wherein: The spraying amount of the polypeptide EGAK is 2-20 mL / branch.

3. A method for improving the quality of Korla fragrant pear, characterized in that: The method for improving the quality of Korla fragrant pear specifically comprises spraying a mixed solution of polypeptide EGAK and 5-ALA on branches of Korla fragrant pear during the fruit expansion period each year, wherein the polypeptide EGAK is synthesized by sequentially connecting peptide bonds of glutamic acid, glycine, alanine and lysine, the spraying concentration of the polypeptide EGAK solution is 50-200 ppm, and the spraying concentration of the 5-ALA solution is 200 ppm.

4. A use of the polypeptide EGAK, characterized in that: The polypeptide EGAK is synthesized by sequentially connecting peptide bonds of glutamic acid, glycine, alanine and lysine. The spraying concentration of the polypeptide EGAK solution is 200-500 ppm, and it is sprayed on the branches of Korla fragrant pear during the fruit expansion period each year to improve the quality of Korla fragrant pear.

5. A solution for improving the quality of Korla fragrant pear, characterized in that: The solution is a 200-500 ppm polypeptide EGAK solution, which is sprayed on branches of Korla fragrant pear during the fruit expansion period each year. The polypeptide EGAK is synthesized by sequentially connecting peptide bonds of glutamic acid, glycine, alanine and lysine.

6. A mixed solution for improving the quality of Korla fragrant pear, characterized in that: The mixed solution is a mixed solution of polypeptide EGAK with a final concentration of 50-200 ppm and 5-ALA with a concentration of 200 ppm, which is sprayed on the branches of Korla fragrant pear during the fruit expansion period every year. The polypeptide EGAK is synthesized by sequentially connecting the peptide bonds of glutamic acid, glycine, alanine and lysine.

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