Composition for promoting peach fruit ripening or improving peach fruit quality and application thereof

Abstract

The invention discloses a composition for improving fruit quality. The composition is prepared from the following raw materials in parts by weight: 0.01 to 0.25 part of 5-aminolevulinic acid, 100 to 260 parts of sugar alcohol and 28 to 45 parts of sodium chloride. The composition or solution provided by the invention can achieve the purposes of effectively improving the plant fruit quality and reducing the intervention cost as much as possible, and the improvement of the fruit quality is mainly reflected in that the plant fruits are matured in advance; the sugar-acid ratio, the vitamin C content, the total flavone content, the total phenol content and the anthocyanin content of the plant fruits are remarkably improved, so that the plant fruits have good quality.

Description

Technical Field

[0001] The invention relates to the field of plant biotechnology, and in particular to a composition for promoting peach fruit ripening or improving peach fruit quality and a use thereof. Background Art

[0002] Peach (Prunus persica L.) belongs to the genus Prunus (Prunus L.) of the Rosaceae family and is one of the important cultivated fruit trees. Peach fruit has high nutritional value and is rich in vitamin C, phenolic substances, sugar acid, etc. It has the functions of anti-oxidation, promoting intestinal peristalsis, and preventing iron deficiency anemia and cardiovascular diseases. Peach fruit is bright in color, sweet and juicy, and has a rich flavor, which is deeply loved by consumers. However, in recent years, with the rapid expansion of peach cultivation area and output, the standardized cultivation technology system is imperfect, resulting in poor quality of peach fruit, poor coloring and light flavor.

[0003] At present, the reagents used to improve fruit quality include sorbitol, sodium chloride and 5-aminolevulinic acid. Sorbitol is a polyol. The sugar metabolism pathway of peach fruit is mainly based on the sorbitol pathway. Sorbitol is the main photosynthetic product and the main transport and soluble sugar storage substance. It is greatly affected by photosynthesis. At the same time, sorbitol can also be converted into glucose and fructose, thereby regulating the balance of sugar components in the fruit. As an abiotic stress, sodium chloride stress can increase the sugar content and antioxidant effect of fruit at an appropriate concentration.

[0004] 5-Aminolevulinic acid (ALA) is a key precursor for the biosynthesis of porphyrin compounds in organisms. Porphyrin compounds are important components of cytochromes, hemoglobin, chloroplast proteins, etc. Therefore, 5-aminolevulinic acid is not only related to plant photosynthesis and respiration, promoting crop flowering, improving the intrinsic quality of fruits, and increasing crop yields, but can also improve plant resistance to salt, drought, waterlogging, cold and other stresses, and improve fruit ripening. It is a plant growth regulator with multiple physiological functions. "Effects of 5-aminolevulinic acid treatment on peach fruit quality and nutritional growth" reported that a 10 mg / mL ALA aqueous solution was used before the peach fruit changed color. One group was sprayed only on the leaves, and the other group was sprayed on the leaves and fruits at the same time. The results showed that after spraying ALA on both the leaves and fruits, the volume of the fruit was significantly increased, and the single fruit weight, longitudinal diameter, transverse diameter and lateral diameter were significantly increased, but there was no effect on the color brightness L* value, red-green deviation a* value and blue-yellow deviation b* value of the fruit; there was no significant effect on the sucrose, glucose and fructose content of the fruit, the sorbitol content was significantly reduced, and the organic acid content did not change significantly; there was no significant effect on the soluble solids content and sugar-acid ratio in the fruit, but spraying the leaves and fruits at the same time could significantly reduce the hardness; at the same time, it could increase the leaf specific gravity of the leaves. "Effects of exogenous 5-aminolevulinic acid on seed germination and antioxidant enzyme activity of perilla seedlings under salt stress" After spraying perilla seeds with exogenous ALA under salt stress, it was found that exogenous ALA can reduce the decrease in relative water content in perilla leaves under salt stress, increase the activity of cell protection enzymes, and protect the integrity of cell membranes, thereby alleviating the damage of salt stress to perilla seeds and seedlings and improving the salt resistance of seeds and seedlings. "Effects of ALA on photosynthesis and fruit yield of different varieties of tomato plants under NaCl stress" A study on spraying exogenous ALA on two tomatoes with different salt tolerance under different salt stress conditions found that spraying exogenous ALA can significantly increase the activity of cell protection enzymes POD, SOD and CAT under salt stress conditions, and reduce the content of malondialdehyde (MDA), which is particularly significant for tomato varieties with weak salt tolerance. Therefore, exogenous ALA can alleviate the inhibitory effect of salt stress on tomato growth and development.

[0005] In addition, studies have reported that the application of exogenous sorbitol alone or in combination during the growing season has a significant effect on peach growth and fruit quality. For example, spraying 5g / L of sorbitol on the young fruit stage of the early-maturing peach variety "Chun Mi" can significantly improve fruit coloring, and spraying 0.5 or 5g / L of sorbitol can increase sucrose accumulation in mature fruits (77 days after full bloom). Similar effects were achieved by spraying sorbitol on the mid-late-maturing peach variety "Da Jiubao": spraying 0.2g / L sorbitol solution twice in mid-to-early June can change the soluble sugar balance of bagged and unbagged fruits that mature in mid-July, indicating that exogenous sorbitol has the ability to regulate the sugar composition of peach fruits.

[0006] However, there are no reports on sorbitol, 5-aminolevulinic acid and sodium chloride regulating plant fruit color or fruit quality. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a composition for improving fruit quality and a preparation method and use thereof.

[0008] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0009] The first aspect of the present invention protects a composition for improving fruit quality, comprising the following raw materials in parts by weight:

[0010] 0.01-0.25 parts of 5-aminolevulinic acid and its precursor

[0011] Sugar alcohol 100-260 parts

[0012] 28-45 parts of sodium chloride.

[0013] In certain embodiments, the weight proportion of the 5-aminolevulinic acid and its precursor can be 0.01 to 0.1 parts, 0.06 to 0.18 parts, 0.12 to 0.25 parts, or 0.01 parts, 0.08 parts, 0.12 parts, 0.15 parts, 0.18 parts, 0.20 parts, 0.02 parts, or 0.25 parts.

[0014] In certain embodiments, the 5-aminolevulinic acid and its precursor are selected from 5-aminolevulinic acid hydrochloride, whose CAS number is 5451-09-2 and molecular formula is C5H9NO3·HCl.

[0015] In some embodiments, the sugar alcohol is selected from one or more of sorbitol, mannitol and isosorbide. The sorbitol is D-sorbitol, which has a CAS number of 50-70-4 and a molecular formula of C6H 14 The CAS number of mannitol is 87-78-5, and the molecular formula is C6H 14 Isosorbide is an isomer of sorbitol. The CAS number of isosorbide is 652-67-5, and the molecular formula is C6H 14 O4, which is a dehydrated derivative of sorbitol.

[0016] In certain embodiments, the weight proportion of the sugar alcohol may be 100-260 parts, 100-180 parts, 160-220 parts, 190-220 parts, 140-220 parts, 100 parts, 120 parts, 140 parts, 155 parts, 160 parts, 180 parts, 200 parts, 210 parts, 220 parts, 240 parts, or 260 parts.

[0017] In certain embodiments, the weight proportion of the sodium chloride may be 28 to 45 parts, 28 to 36 parts, 38 to 45 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, or 45 parts.

[0018] In a more specific embodiment, the following raw materials are included in parts by weight:

[0019] 5-aminolevulinic acid and its precursors 0.01 parts

[0020] Sugar alcohol 145.7 parts

[0021]

[0022] The second aspect of the present invention protects a solution for improving fruit quality, comprising the composition as described above and a solvent.

[0023] In certain embodiments, the solvent is selected from water, and the mass volume ratio of the composition to the solvent is (150-300) g:10L.

[0024] In certain embodiments, based on the total mass of the solution, the concentration of 5-aminolevulinic acid and its precursor is 0.01-0.25 g / 10L, or 0.06-0.18 g / 10L, or 0.12-0.25 g / 10L, or 0.01 g / 10L, 0.08 g / 10L, 0.12 g / 10L, 0.15 g / 10L, 0.18 g / 10L, 0.20 g / 10L, 0.02 g / 10L, or 0.25 g / 10L.

[0025] In certain embodiments, based on the total mass of the solution, the concentration of the sugar alcohol is 100-260 g / 10L, or 100-180 g / 10L, or 160-220 g / 10L, or 190-220 g / 10L, or 140-220 g / 10L, or 100 g / 10L, 120 g / 10L, 140 g / 10L, 155 g / 10L, 160 g / 10L, 180 g / 10L, 200 g / 10L, 210 g / 10L, 220 g / 10L, 240 g / 10L, or 260 g / 10L.

[0026] In certain embodiments, based on the total mass of the solution, the concentration of sodium chloride is 28-45 g / 10L, or 28-36 g / 10L, or 38-45 g / 10L, or 28 g / 10L, 30 g / 10L, 32 g / 10L, 34 g / 10L, 36 g / 10L, 38 g / 10L, 40 g / 10L, 42 g / 10L, 44 g / 10L, or 45 g / 10L.

[0027] In a more specific embodiment, the solution comprises 0.01 g / 10L of 5-aminolevulinic acid, 145.7 g / 10L of sugar alcohol, and 35.1 g / 10L of sodium chloride.

[0028] The third aspect of the present invention protects the use of the composition as described above or the solution as described above in promoting the ripening of peach fruit or improving the quality of peach fruit.

[0029] In certain embodiments, the promoting ripening of peach fruit refers to improving any one or more of A1)-A3): A1) comprehensive color difference index; A2) anthocyanin content; A3) sugar-acid ratio.

[0030] The sugar-acid ratio is a key indicator for measuring the sweetness and acidity of fruits. It reflects the ratio of sugar to acid in fruits. When the sugar-acid ratio increases, fruits usually taste sweeter because the sugar content is higher. Ripe fruits often have a more suitable sugar-acid ratio, which makes them taste sweeter. Therefore, the sugar-acid ratio is often used to determine whether the fruit is ripe. The present invention found that spraying 5-aminolevulinic acid, sugar alcohol, and sodium chloride solution alone can increase the sugar-acid ratio in fruits, but without significant effect; the combination of sorbitol and 5-aminolevulinic acid has no significant effect on the sugar-acid ratio; while the combination of sorbitol and sodium chloride reduces the sugar-acid ratio; the combination of 5-aminolevulinic acid, sugar and sodium chloride has the best effect on improving the sugar-acid ratio, which is 1.30 times that of the control group.

[0031] The color of the fruit usually changes from green to red when ripe, and the intuitive change in skin color is often used in production to judge and infer the maturity of fruits and vegetables. The color difference comprehensive index CCI is an indicator for judging color. The present invention found that spraying 5-aminolevulinic acid alone can increase the CCI index, spraying sodium chloride alone has no effect on CCI, and spraying sorbitol alone reduces CCI; while the combination of sorbitol and 5-aminolevulinic acid increases CCI, indicating that the addition of 5-aminolevulinic acid can improve the reduction of CCI caused by sorbitol; compared with the sorbitol group alone, the combination of sorbitol and sodium chloride increases CCI, indicating that the addition of sodium chloride can improve the reduction of CCI caused by sorbitol; but the combination of 5-aminolevulinic acid, sugar and sodium chloride has the greatest effect on CCI, which is 1.19 times that of the control group.

[0032] The anthocyanin content in mature fruits is the best, so the anthocyanin content is also one of the indicators for judging the maturity of fruits. The present invention finds that spraying 5-aminolevulinic acid, sugar alcohol, and sodium chloride solution alone can increase the anthocyanin content of fruits; the combination of sorbitol and 5-aminolevulinic acid has no significant effect on the anthocyanin content of fruits; the combination of sorbitol and sodium chloride can significantly increase the anthocyanin content; but the anthocyanin content in the combination of 5-aminolevulinic acid, sugar and sodium chloride is the highest, which is 1.25 times that of the control group.

[0033] In certain specific embodiments, improving the plant fruit quality refers to improving any one or more of B1)-B3): B1) total flavonoids content; B2) vitamin C content; B3) total phenol content.

[0034] Flavonoids are a type of secondary metabolites widely found in fruits and vegetables. Recently, it has been found that they have a strong ability to scavenge free radicals. Flavonoids can inhibit angiotensin converting enzymes that cause elevated blood pressure, and help prevent chronic diseases such as cardiovascular disease and coronary heart disease, and reduce their incidence. The present invention finds that spraying 5-aminolevulinic acid, sugar alcohol, and sodium chloride solutions alone can increase the content of flavonoids in fruits, wherein the content of flavonoids is the highest when 5-aminolevulinic acid is sprayed alone; the combination of sorbitol and sodium chloride has no effect on the content of flavonoids; the combination of sorbitol and 5-aminolevulinic acid can also increase the content of flavonoids in fruits; but the combination of 5-aminolevulinic acid, sugar, and sodium chloride has the best effect on increasing the content of flavonoids, which is 1.54 times that of the control group.

[0035] Vitamin C plays an important role in human life activities. It can prevent free radicals from harming the human body, improve human immunity, prevent arteriosclerosis, prevent cancer, and improve the body's emergency response ability, and participate in collagen synthesis and treatment of scurvy, etc. However, the human body lacks some enzymes for synthesizing vitamin C, so it is necessary to obtain vitamin C from food or medicine. Since natural vitamin C is far superior to synthetic vitamin C in absorption effect and efficacy, how to increase the natural vitamin C content of fruits and vegetables has become an important issue that researchers are concerned about today. The present invention finds that spraying 5-aminolevulinic acid, sugar alcohol, and sodium chloride solution alone can increase the vitamin C content in the fruit, wherein the vitamin C content is the highest when 5-aminolevulinic acid is sprayed alone; the combination of sorbitol and sodium chloride and the combination of sorbitol and 5-aminolevulinic acid can also increase the vitamin C content in the fruit; the combination of 5-aminolevulinic acid, sugar and sodium chloride can also increase the vitamin C content in the fruit, and is the highest, which is 1.72 times that of the control group.

[0036] The fourth aspect of the present invention protects a method for promoting peach fruit ripening or improving peach fruit quality, comprising the following steps:

[0037] Peaches were sprayed with the solution as described above.

[0038] In certain embodiments, the spraying is performed on the leaves or fruits during the fruit expansion period of the plant.

[0039] In some embodiments, the spraying is performed once every 5 to 9 days. Each time, the spraying amount per peach tree is 0.3 to 2 L of solution, or 0.3 to 0.8 L of solution, or 0.7 to 1.5 L of solution, or 1.2 to 2 L of solution, and in a specific embodiment, 0.6 L of solution.

[0040] In certain embodiments, the number of spraying is at least 3 times, or 3 to 12 times, or 3 to 5 times, or 4 to 8 times, or 7 to 12 times, and in a specific embodiment, it is 5 times.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The composition or solution of the present invention can improve the quality of peach fruit while reducing the intervention cost as much as possible. After spraying the composition or solution on peach trees, the composition or solution can promote the increase of sugar-acid ratio, anthocyanin content and color difference comprehensive index, so that the fruit matures earlier. In addition, the vitamin C content, total flavonoid content and total phenol content of peach are also increased, so that the peach fruit has good quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Shown is a statistical graph of the CCI index of peach fruits in different groups in Example 1 of the present application.

[0044] Figure 2 Shown is a statistical chart of the sugar-acid ratio in peach fruits of different groups in Example 1 of the present application.

[0045] Figure 3 Shown is a statistical chart of total flavonoids, vitamin C content and anthocyanins in different groups of peach fruits in Example 1 of the present application.

[0046] Figure 4 Shown is a statistical graph of chlorophyll in peach leaves of different groups in Example 1 of the present application. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0048] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing the specific embodiments rather than for limiting the scope of protection of the present invention; in the present specification and claims, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0049] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0050] In the following examples of the present application, D-sorbitol powder, 5-aminolevulinic acid powder and sodium chloride powder were purchased from Beijing Coolaibo Technology Co., Ltd. (item number: CS10381), Yuanye (item number: S30944) and Tuoyingfang (item number: S805275), respectively.

[0051] Example 1

[0052] 1.1 Experimental subjects

[0053] The research object is the "Chunxue" peach variety in a greenhouse in a planting base in Changli, Hebei Province. Ordinary rootstock, plant spacing 2m×5m, two main branches in a Y shape, east-west direction.

[0054] When peach fruits entered the expansion stage S1, 21 peach trees with strong vigor, basically uniform growth and no diseases or insect pests were selected from the greenhouse and randomly divided into 7 groups, with 3 peach trees in each group, and the groups of the trees were marked with signs.

[0055] 1.2 Experimental Grouping

[0056] The experiment was designed with seven treatments:

[0057] (1) Control: clean water treatment (control example).

[0058] (2) Experimental group 1: sorbitol 100 mM (18.22 g / L) (Example 1).

[0059] (3) Experimental group 2: 1 mg / L 5-aminolevulinic acid (Example 2).

[0060] (4) Experimental group 3: 30 mM sodium chloride (3.51 g / L) (Example 3).

[0061] (5) Experimental group 4: sorbitol 80 mM + 5-aminolevulinic acid 1 mg / L (Example 4).

[0062] (6) Experimental group 5: sorbitol 80 mM + sodium chloride 30 mM (Example 5).

[0063] (7) Experimental Group 6: sorbitol 80 mM (14.57 g / L) + 5-aminolevulinic acid 1 mg / L + sodium chloride 30 mM (3.51 g / L) (Example 6).

[0064] The control group was sprayed with distilled water only, while the other experimental groups used distilled water as the solvent to prepare the solutions.

[0065] Each group was sprayed with the corresponding solution at the fruit expansion stage S1, and then sprayed again every 7 days, for a total of 5 times, namely S2 (S1+7 days), S3 (S2+7 days), S4 (S3+7 days) and S5 (S4+7 days), and the fruits were picked at S6 (S5+7 days). The fruits in the S3 and S4 stages were bagged. Each time, 2L of solution was sprayed on 3 peach trees in each group.

[0066] Each group sprayed the corresponding solution on fruits and leaves simultaneously during S1, S2 and S5, and only sprayed leaves during S3 and S4. Each spraying was carried out evenly until water droplets fell.

[0067] 1.3、Indicator test

[0068] The test plants were grown in greenhouses at a temperature of 25°C to 28°C, with humidity maintained at 80%-90% in the early stage (before budding), 60%-70% in the middle stage (flowering stage), and 50%-60% in the late stage (fruit development stage). The fruits were harvested when the peach fruits reached 80% commercial maturity (S6 picking), and the leaves were harvested once on the last day of each stage. The fruit color was measured using fresh fruit, and the other measurement indicators were all based on the powder obtained by freeze-drying and grinding the fruit after the color measurement, that is, the fruit freeze-dried powder.

[0069] 1.3.1 Fruit color

[0070] The measurement was carried out using a colorimeter, using the color brightness L* value, red-green deviation a* value, blue-yellow deviation b* value, and color difference comprehensive index CCI (CCI = 1000×a* / (L*×b*)). Positive CCI values ​​represent the degree of red and yellow, and negative values ​​represent the degree of blue and green.

[0071] The L* value indicates brightness, the larger the value, the higher the brightness; the a* value indicates the difference between red and green, the larger the value, the redder, and the smaller the value, the greener; the b* value indicates the difference between yellow and blue, the larger the value, the yellower, and the smaller the value, the bluer.

[0072] 1.3.2. Fruit soluble sugar content

[0073] The anthrone colorimetric method was used for determination.

[0074] 1) Preparation of standard curve: Take 6 test tubes and add reagents according to the data in the table below. Shake well immediately, react for 10 minutes, compare colors at a wavelength of 620nm, and obtain the absorbance value. Draw a standard curve with the standard glucose concentration as the horizontal axis and the absorbance value as the vertical axis.

[0075] Table 1

[0076] Test tube number 1 2 3 4 5 6 Standard glucose solution (mL) 0 0.4 0.8 1.2 1.6 2.0 Distilled water (mL) 2.0 1.6 1.2 0.8 0.4 0 Glucose concentration (ug / mL) 0 10 20 30 40 50 Anthrone reagent (mL) 4 4 4 4 4 4

[0077] 2) Weigh 10 g of freeze-dried fruit powder, grind it into a homogenous slurry in a mortar, and distill it together with the residue to 100 mL. Extract at room temperature for 30 min, shaking frequently, centrifuging or filtering, and discarding the residue.

[0078] 3) Dilute 10 times before measurement, pipette 2 mL of the diluted solution into a test tube, add 4 mL of anthrone reagent, shake well, and compare colors at 620 nm after 10 minutes, record the absorbance value, and find the concentration of glucose from the standard curve.

[0079] Calculation formula

[0080]

[0081] Where: m' is the mass of glucose obtained from the standard curve (ug); V is the total volume of the sample extract (mL); N is the dilution factor of the sample extract; Vs is the volume of the sample extract taken during the determination (mL); and m is the mass of the sample (g).

[0082] 1.3.3. Titratable acid content of fruit

[0083] The NaOH titration method is used for determination. The specific operation is:

[0084] Weigh 10g of fruit freeze-dried powder, grind it in a mortar, transfer it to a 100mL volumetric flask, rinse the mortar with distilled water, transfer it to the volumetric flask, and dilute to the mark, shake well. Let it stand for 30 minutes and filter. Take 20mL of the filtrate, transfer it to a conical flask, add 2 drops of 1% phenolphthalein indicator, and titrate with a calibrated sodium hydroxide solution. Titrate until the solution begins to turn pink and does not fade within 30 seconds, record the amount of sodium hydroxide titrant used, and repeat three times.

[0085] At the same time, distilled water was used instead of the filtrate for titration as a blank control.

[0086] Calculation results

[0087]

[0088] Where: V is the total volume of the extract (mL), that is, the sample and distilled water; C is the concentration of the NaOH solution (mol / L); V1 is the consumption of the NaOH solution during the determination (mL); V0 is the consumption of the NaOH solution during the blank determination (mL); f is the conversion coefficient -0.067 (taking malic acid as an example); Vs is the volume of the filtrate taken (mL).

[0089] 1.3.4 Vitamin C content of fruits

[0090] 2,6-dichlorophenol indophenol was used for determination. The specific operation is as follows:

[0091] Reagents: 2% oxalic acid: weigh 10 g of oxalic acid and dissolve it in a small amount of distilled water and make up to 500 mL.

[0092] 2,6-Dichlorophenol indophenol: Dissolve 50 mg of 2,6-dichlorophenol indophenol dye in 200 mL of hot water containing 52 mg of NaHCO3. After cooling, dilute to 250 mL, put into a brown bottle, and store in the refrigerator.

[0093] Standard ascorbic acid solution: Dissolve 50 mg of pure ascorbic acid in a small amount of 2% oxalic acid solution, and then dilute to 500 mL with 2% oxalic acid solution. (Prepare and use immediately)

[0094] 1) Extraction: Weigh 0.5g of freeze-dried fruit powder, add about 5mL of 2% oxalic acid solution into a mortar and grind it. Pour the ground sample into a 100mL volumetric flask through a funnel, rinse the mortar with 2% oxalic acid, and pour the washing solution into the volumetric flask, and finally dilute to the mark with 2% oxalic acid. Filter and set the filtrate aside.

[0095] 2) Calibration: Take 10 mL of standard ascorbic acid solution into an evaporating dish and titrate with 2,6-dichlorophenol indophenol solution until it turns pink and does not fade within 30 seconds. Calibrate 2,6-dichlorophenol indophenol solution. Calculate the number of milligrams of ascorbic acid equivalent to 1 mL of dye.

[0096]

[0097] A is the number of mg of ascorbic acid equivalent to 1 mL of dye solution; C is the concentration of ascorbic acid (mg / mL); V1 is the volume of ascorbic acid used for calibration (mL); V2 is the volume of dye consumed for calibration (mL).

[0098] 3) Titration: Take 10 mL of the filtrate in step 1) in an evaporating dish and titrate with the calibrated 2,6-dichlorophenol indophenol solution in step 2) until it turns pink and does not fade within 30 seconds. Record the amount of dye 2,6-dichlorophenol indophenol used (repeat 3 times and take the average value).

[0099] At the same time, distilled water was used instead of the filtrate for titration as a blank control.

[0100] Calculation results

[0101]

[0102] Wherein: W is the ascorbic acid content of the sample (mg / 100g); Y1 is the amount of dye used for blank titration (mL); Y0 is the amount of dye used for sample titration (mL); B is the sample weight (g); X is the volume of the sample titration solution (mL); Z is the total volume of the sample solution after volume adjustment (mL).

[0103] 1.3.5. Total flavonoids content of fruits

[0104] The aluminum nitrate colorimetric method is used for determination. The specific operation is as follows:

[0105] 1) The freeze-dried powder of the fruit was added to 80% acetone at a solid-liquid ratio of 1:10 (g / mL), extracted overnight, shaken with a vortexer, and ultrasonicated with an ultrasonic cleaner at 40°C. The ultrasonic power of the ultrasonic extraction was 200 W, the ultrasonic time was 1 h, and the ultrasonic was performed twice to obtain an extract.

[0106] 2) Centrifuge the extract at 10,000 r for 10 min and take the supernatant.

[0107] 3) First add 1 mL of supernatant to a volumetric flask, then add 0.3 mL of 5% sodium nitrite solution, shake thoroughly, and let stand for 6 min; then add 0.3 mL of 10% aluminum nitrate solution, shake thoroughly, and let stand for 6 min; finally add 4 mL of 4% sodium hydroxide solution, shake thoroughly, let stand for 15 min, then dilute to 10 mL with distilled water, and measure the absorbance A (rutin) at 510 nm.

[0108] Rutin standard curve:

[0109] The calculation formula for total flavonoid content is (mg / g):

[0110]

[0111] Wherein: C, mass concentration of rutin, mg / mL; V1, volume of extract used for determination, mL; V2, total volume of extract, mL; M, weight of peach fruit, g.

[0112] 1.3.6 Determination of total phenolic content in fruits

[0113] The Folin-phenol method was used for determination. The specific operation is as follows:

[0114] 1) The freeze-dried powder of the fruit was added to 80% acetone at a solid-liquid ratio of 1:10 (g / mL), extracted overnight, shaken with a vortexer, and ultrasonicated with an ultrasonic cleaner at 40°C. The ultrasonic power of the ultrasonic extraction was 200 W, the ultrasonic time was 1 h, and the ultrasonic was performed twice to obtain an extract.

[0115] 2) Centrifuge the extract at 10,000 r for 10 min and take the supernatant.

[0116] 3) Take 40 μL of the supernatant, add 1.8 mL of FC (Folin phenol) reagent diluted 10 times (solid state needs to be melted) (protect from light after preparation), protect from light for 5 min, then add 1.2 mL of 7.5% Na2CO3 aqueous solution, protect from light for 1.5 h, and measure the absorbance A (gallic acid) at 765 nm.

[0117] Gallic acid standard curve:

[0118] Total phenol content calculation formula (mg / g)

[0119]

[0120] Where: C, mass concentration of gallic acid, mg / mL; V1, volume of extract used for determination, mL; V2, total volume of extract, mL; M, weight of peach fruit, g.

[0121] 1.3.7 Determination of anthocyanin content in fruits

[0122] The hydrochloric acid methanol method is used for determination. The specific operation is:

[0123] 1) Take 0.1 g of fruit freeze-dried powder and immerse it in 600 μL of 1% hydrochloric acid methanol and incubate it at 4°C overnight.

[0124] 2) After adding 400 μL ddH2O, the solution was centrifuged at 3800 rpm for 10 min.

[0125] 3) Collect the supernatant after centrifugation and add 1 mL of chloroform, mix by inversion, then centrifuge the mixture at 13,000 rpm for 5 min and take the aqueous phase.

[0126] 4) The anthocyanin content in the aqueous phase was measured using a spectrophotometer at 530 nm and 657 nm, respectively, and calculated using the formula (A530-A657) / Fw.

[0127] 1.4 Test results

[0128] 1.4.1. Effect on fruit color

[0129] The fruit color results of each group are shown in Table 1 and Figure 2 .

[0130] Table 1

[0131] CCI Soluble solids% Soluble sugar mg / g Titratable acid mg / g Sugar-acid ratio Comparison example 27.57±3.89b 7.74±0.18a 1.17±0.015a 2.72±0.20bc 0.43±0.04bc Example 1 29.50±2.08ab 7.92±0.08a 1.18±0.012a 2.81±0.13b 0.43±0.03bc Example 2 22.83±2.73c 8.00±0.10a 1.18±0.015a 2.37±0.15c 0.50±0.03ab Example 3 26.75±2.84b 7.90±0.10a 1.18±0.006a 2.77±0.28bc 0.43±0.04bc Example 4 29.05±5.22ab 7.67±0.42a 1.17±0.012a 2.72±0.41bc 0.40±0.02cd Example 5 25.64±4.04bc 7.67±0.23a 1.16±0.006a 3.35±0.13a 0.35±0.01d Example 6 32.80±5.84a 7.97±0.15a 1.17±0.006a 2.37±0.08c 0.56±0.07a

[0132] From Table 1 and Figure 1 It can be seen that the peach fruits treated with Examples 3, 4, 5, and 6 significantly increased the red-green deviation a* value compared with the control, which was 1.18 times, 1.29 times, 1.17 times, and 1.21 times that of the control.

[0133] Depend on Figure 1 It can be seen that the treatments in Examples 1, 4 and 6 significantly increased the color difference comprehensive index CCI of peach fruit, which were 1.07 times, 1.05 times and 1.19 times that of the control group, respectively.

[0134] 1.4.2 Effect on the sugar-acid ratio of fruits

[0135] The sugar-acid ratio results of each group are shown in Table 1 and Figure 2 .

[0136] From Table 1 and Figure 2 It can be seen that compared with the control group, the sugar-acid ratio of experimental group 4 combined with sorbitol and 5-aminolevulinic acid did not increase, but decreased; compared with the control group, the sugar-acid ratio of experimental group 5 combined with sorbitol and sodium chloride did not increase, but decreased; compared with the control group, experimental group 6 combined with sorbitol, 5-aminolevulinic acid and sodium chloride significantly increased the sugar-acid ratio of the fruit (p < 0.05), which was 1.30 times that of the control group, while having no significant effect on the soluble solids and soluble sugar content of the fruit.

[0137] 1.4.3 Effects on total flavonoids, total phenols and vitamin C content in fruits

[0138] The total flavonoid results of each group are shown in Table 2 and Figure 2 .

[0139] From Table 2 and Figure 3 As shown in Figure A, compared with the control group, the total flavonoids content of experimental group 4 in combination of sorbitol and 5-aminolevulinic acid did not increase, but decreased; compared with the control group, the total flavonoids content of experimental group 5 in combination of sorbitol and sodium chloride increased by 1.29 times; compared with the control group, the total flavonoids content of experimental group 6 in combination of sorbitol, 5-aminolevulinic acid and sodium chloride increased by 1.54 times.

[0140] The results of vitamin C content in each group are shown in Table 2 and Figure 3 .

[0141] Table 2

[0142] Total flavonoids (mg / g) Total phenols (mg / g) Vitamin C (mg / 100g) Anthocyanin (A530-A657) / FW Comparison example 2.94±0.35de 2.35±0.05d 1.64±0.19e 0.64±0.02d Example 1 3.37±0.1cd 3.46±0.09abc 2.12±0.27cd 0.75±0.00bc Example 2 3.91±0.21b 3.57±0.36ab 2.50±0.05ab 0.77±0.01ab Example 3 3.34±0.32cd 2.33±0.44d 2.46±0.10bc 0.74±0.01bc Example 4 2.80±0.25e 3.01±0.41c 2.00±0.31d 0.66±0.04d Example 5 3.78±0.31bc 3.31±0.27bc 2.00±0.18d 0.73±0.01c Example 6 4.53±0.35a 3.90±0.18a 2.82±0.09a 0.80±0.00a

[0143] From Table 2 and Figure 3 It can be seen from C that the vitamin C content of each experimental group was increased compared with the control group; compared with the control group, the vitamin C content of experimental group 4 in combination of sorbitol and 5-aminolevulinic acid increased by 1.22 times; compared with the control group, the vitamin C content of experimental group 5 in combination of sorbitol and sodium chloride increased by 1.22 times; compared with the control group, the vitamin C content of experimental group 6 in combination of sorbitol, 5-aminolevulinic acid and sodium chloride increased by 1.72 times.

[0144] The results of total phenol content in each group are shown in Table 2 and Figure 3 .

[0145] From Table 2 and Figure 3 As shown in Figure B, compared with the control group, the total phenol content of experimental group 4, which was a combination of sorbitol and 5-aminolevulinic acid, increased by 1.28 times; compared with the control group, the total phenol content of experimental group 5, which was a combination of sorbitol and sodium chloride, increased by 1.41 times; compared with the control group, the total phenol content of experimental group 6, which was a combination of sorbitol, 5-aminolevulinic acid and sodium chloride, increased by 1.66 times.

[0146] 1.4.4 Effect on anthocyanin content in fruits

[0147] The results of anthocyanin content in each group are shown in Table 2 and Figure 3 .

[0148] From Table 2 and Figure 3 As shown in Figure D, compared with the control group, the anthocyanin content of experimental group 4 in combination of sorbitol and 5-aminolevulinic acid increased by 1.03 times; compared with the control group, the anthocyanin content of experimental group 5 in combination of sorbitol and sodium chloride increased by 1.14 times; compared with the control group, the anthocyanin content of experimental group 6 in combination of sorbitol, 5-aminolevulinic acid and sodium chloride increased by 1.25 times.

[0149] 1.4.5. Effects on leaf chlorophyll content

[0150] from Figure 4 As shown in A, compared with the control group, in the S3 and S5 periods, Example 2, Example 3, Example 5 and Example 6 all increased the chlorophyll a content of leaves by 1.16 times, 1.14 times, 1.14 times and 1.12 times, respectively, in the S3 period, and by 1.21 times, 1.06 times, 1.12 times and 1.17 times, respectively, in the S5 period.

[0151] from Figure 4As shown in Figure B, compared with the control group, Example 2 increased the chlorophyll b content of leaves at S3 and S5 stages, increasing by 1.15 times at S3 stage and 1.11 times at S5 stage.

[0152] from Figure 4 As shown in Figure C, compared with the control group, in the S3 and S5 periods, Example 2, Example 5 and Example 6 all increased the total chlorophyll content by 1.16 times, 1.12 times and 1.08 times, respectively, in the S3 period, and by 1.16 times, 1.06 times and 1.11 times, respectively, in the S5 period.

[0153] The above examples are for the purpose of illustrating the embodiments disclosed by the present invention and are not to be construed as limitations of the present invention. In addition, the various modifications listed herein and the variations of methods and compositions in the invention are obvious to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been specifically described in conjunction with various specific preferred embodiments of the present invention, it should be understood that the present invention should not be limited to these specific embodiments. In fact, various modifications obvious to those skilled in the art as described above to obtain the invention should be included within the scope of the present invention.

Claims

1. A composition for promoting peach fruit ripening or improving peach fruit quality, characterized in that: Contains the following raw materials in parts by weight: 0.01-0.25 parts of 5-aminolevulinic acid and its precursor Sugar alcohol 100-260 parts 28-45 parts of sodium chloride.

2. The composition according to claim 1, characterized in that The sugar alcohol is selected from one or more of sorbitol, mannitol and isosorbide; And / or, the 5-aminolevulinic acid and its precursor are selected from 5-aminolevulinic acid hydrochloride.

3. The composition according to claim 2, characterized in that The weight portion of the 5-aminolevulinic acid and its precursor is 0.01 to 0.1 parts; and / or, the weight portion of the sugar alcohol is 140 to 220 parts; And / or, the weight portion of the sodium chloride is 35 to 40 parts.

4. A solution for promoting peach fruit ripening or improving peach fruit quality, characterized in that: The method comprises the composition according to any one of claims 1 to 3 and a solvent.

5. The solution according to claim 4, characterized in that The solvent is selected from water, and the mass volume ratio of the composition to the solvent is (150-300) g:10L.

6. Use of the composition according to claim 1 or the solution according to claim 4 in promoting ripening of peach fruit or improving the quality of peach fruit.

7. The use according to claim 6, characterized in that The promoting of peach fruit ripening refers to improving any one or more of A1)-A3): A1) comprehensive color difference index; A2) anthocyanin content; A3) sugar-acid ratio.

8. The use according to claim 6, characterized in that Improving the fruit quality refers to improving any one or more of B1)-B3): B1) total flavonoid content; B2) vitamin C content; B3) total phenol content.

9. A method for promoting peach fruit ripening or improving peach fruit quality, characterized in that: These include: Spray the solution as claimed in claim 4 onto peaches.

10. The method according to claim 9, characterized in that During the fruit expansion period of the plant, spray the leaves or fruits; And / or, spray once every 5 to 9 days; And / or, the number of spraying is at least 3 times.

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