A method for promoting coloring of red pears using brassinolide

Abstract

The present invention relates to the technical field of fruit coloring, and in particular to a method for promoting the coloring of red pears using brassinolide. A method for promoting the coloring of red pears using brassinolide comprises: subjecting red pears that have reached physiological maturity but have not yet been colored to light coloring treatment, and before light irradiation, soaking the red pear fruit in a soaking solution containing 24-epibrassinolide. The present invention first discovered that the brassinolide analogue 24-epibrassinolide can induce the accumulation of anthocyanins in the peel of red pears, significantly promote the coloring process of the peel of red pears, make the surface color of the fruit more vivid and uniform, thereby enhancing the commodity value and market competitiveness of the fruit. The method of the present invention has low reagent concentration, low requirements on equipment conditions, strong operability, high efficiency and simplicity.

Description

Technical Field

[0001] The invention relates to the technical field of fruit coloring, and in particular to a method for promoting the coloring of red pears by utilizing brassinolide. Background Art

[0002] Pear is a perennial deciduous fruit tree belonging to the genus Pyrus in the Rosaceae family. It is widely planted all over the world and is loved for its crisp taste and rich nutritional value. Among them, red pears are loved by consumers for their bright color and high anthocyanin content. Anthocyanins not only give red pears beautiful color, but also have antioxidant and anti-cancer properties, which play an important role in human health. However, the cultivation process found that red pears have an industrial problem of poor coloring, which directly affects the market value and economic benefits of red pear fruits.

[0003] At present, the coloring regulation technology of red pears has been reported. The patent with the authorization announcement number CN106721952B discloses the use of 1-methylcyclopropene as a red pear coloring accelerator. This method is to color the uncolored red pears that have reached the physiological maturity period by light exposure. Before light exposure, the red pears are fumigated in a 1-methylcyclopropene atmosphere with a concentration of 0.1~1.0 ppm. The fumigation time is 12~20 h and the fumigation temperature is 0~30℃. After fumigation, the red pears are immersed in a 1-methylcyclopropene atmosphere with a concentration of 1~4 mmol•L -1 The method can shorten the coloring time of red pears, but the operation steps are complicated and the fumigation requirements are strict. The patent with the authorization announcement number CN102150819B discloses a red sand pear post-harvest coloring device and method. The method places the uncolored sand pears at physiological maturity under UV-B light intensity of 1~2 μmol•m -2 •s -1 , white light intensity is 3~4 μmol•m -2 •s -1 , and placed in an environment with an average temperature of 25-29°C and an average relative humidity of 55-75% for 5-10 days. This method can obtain fruits with relatively full, stable and uniform coloring. However, this method has strict requirements on light conditions and is less operable. Summary of the invention

[0004] Based on the above, the purpose of the present invention is to provide a method for promoting the coloring of red pears using brassinolide, which can significantly improve the color and appearance quality of red pears by using brassinolide to induce the accumulation of anthocyanins in the peel of red pears, and is more efficient and simple.

[0005] The technical solution adopted by the present invention to achieve the technical purpose is:

[0006] A method for promoting the coloring of red pears by using brassinolide comprises: subjecting red pears that have reached physiological maturity but have not yet been colored to light coloring treatment, and before the light exposure, soaking the red pears in a soaking solution containing 24-epibrassinolide (EBL).

[0007] Preferably, the red pears include red sand pear, red western pear and red hybrid pear (sand pear×western pear), specifically varieties such as 'Hong Zao Su' pear.

[0008] In order to ensure the effectiveness of the brassinolide treatment, red pears that have reached physiological maturity but have not been colored are picked and then colorized.

[0009] Preferably, the concentration of 24-epibrassinolide in the soaking solution is 1-5 μmol / L, the soaking time is 5-30 min, and the soaking temperature is 4-35°C.

[0010] The soaking time of red pear fruit in 24-epibrassinolide should be appropriate. Too long soaking time will cause the red pear fruit to wilt and reduce its quality; too short soaking time will make it difficult to achieve the treatment effect.

[0011] More preferably, the concentration of 24-epibrassinolide in the soaking solution is 3 μmol / L, the soaking time is 15 min, and the soaking temperature is 25°C.

[0012] 24-Epibrassinolide can induce the accumulation of anthocyanins in the peel of red pears. Compared with natural light conditions, the coloring of the soaked red pears is more uniform and stable, and the effect is more obvious.

[0013] Testing showed that the anthocyanin content in the peel of red pears treated with 24-epibrassinolide was significantly higher than that in naturally grown red pears.

[0014] In order to promote the hormones to adhere to the surface of the red pear fruit and to play a better role, a surfactant is also added to the soaking solution.

[0015] Preferably, the soaking solution contains 0.1-0.5% by volume of a surfactant. The "volume percentage" herein refers to the percentage of the volume of the added surfactant in the total volume of the soaking solution.

[0016] More preferably, the surfactant is 0.2% by volume of Tween-20.

[0017] Preferably, the light coloring treatment is: under a white light intensity of 50-120 μmol•m -2 •s -1 Let it stand in an environment for 5 to 10 days.

[0018] More preferably, the temperature in the environment is 15-20° C. and the relative humidity is 70-90%.

[0019] Light is one of the most important factors affecting the synthesis of anthocyanins in red pear fruit. It can promote the expression of the structural gene phenylalanine ammonia lyase ( PAL )、Chalcone synthase( CHS )、Chalcone isomerase( CHI )、flavanone 3-hydroxylase( F3H )、Dihydroflavonol reductase( DFR )、Anthocyanidin synthase( ANS ) and flavonoid 3-O-glycosyltransferase ( UFGT ) expression, thereby promoting the accumulation of anthocyanins and fruit coloring. The intensity and quality of light are important factors affecting the coloring of red pears. Preferably, the white light intensity is 110 μmol•m -2 •s -1 .

[0020] Temperature is another important environmental factor that affects the synthesis of anthocyanins in red pear fruit. Studies have shown that high temperatures inhibit the accumulation of anthocyanin precursors, thereby inhibiting fruit coloring; while appropriate low temperature conditions increase the expression of anthocyanin synthesis genes, thereby inducing anthocyanin accumulation and promoting fruit coloring. Preferably, the temperature is 17°C, and the coloring effect is the best.

[0021] Relative humidity is a matter that requires special attention during the storage of red pear fruits. Too high humidity is conducive to the growth of pathogens and easily causes the fruit to rot, while too low humidity will cause the water in the fruit to evaporate and lose its taste. Preferably, the relative humidity is 80%.

[0022] The present invention has the following beneficial effects:

[0023] (1) The present invention discovers for the first time that the brassinolide analog 24-epibrassinolide can induce the accumulation of anthocyanins in the red pear peel, significantly promoting the coloring process of the red pear peel, making the color of the fruit surface brighter and more uniform, thereby enhancing the commercial value and market competitiveness of the fruit.

[0024] (2) The method of the present invention has low reagent concentration, low requirements on equipment conditions, strong operability, high efficiency and simplicity, and high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The pictures of the initial fruits of the 'Hong Zao Su' pear in Example 1 are compared with the pictures of the fruits after being treated with different concentrations of EBL for 1, 3, and 5 days.

[0026] Figure 2The picture of the initial fruit of 'Hong Zao Su' pear in Example 2 is compared with the picture of the fruit after 10 days of treatment with 3 μmol / L EBL.

[0027] Figure 3 This is the effect of EBL on the color difference of the fruit skin near the light side of 'Hongzaosu' pear under white light induction conditions.

[0028] Figure 4 This is the effect of EBL on the anthocyanin content of the fruit peel near the light side of 'Hongzaosu' pear under white light induction conditions.

[0029] Figure 5 This is the effect of EBL on the soluble solids of 'Hongzaosu' pear under white light induced conditions.

[0030] Figure 6 This is the effect of EBL on the firmness of 'Hongzaosu' pear fruit under white light induced conditions. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with specific implementation methods. The following specific embodiments are helpful for those skilled in the art to further understand the present invention, but do not limit the present invention in any form.

[0032] Example 1

[0033] 1. Reagent processing

[0034] ① The red pear variety 'Hong Zao Su' was collected from the Zhengzhou Comprehensive Experimental Station of the National Pear Industry System in July 2024. The fruits were covered with light-proof double-layer fruit bags 40 days after full bloom until they reached physiological maturity. After the ripe fruits were harvested, they were immediately transported back to the laboratory, and the fruits of uniform size, without mechanical damage, cracking, disease, insects and rot were selected for processing.

[0035] ② The experiment was divided into 4 groups, including a control group and a treatment group, as shown in Table 1. After soaking, the samples were placed in a light-proof environment to dry.

[0036] Preparation of soaking solution: 2,4-epibrassinolide is a solid powder. Before use, it must be dissolved in dimethyl sulfoxide (DMSO) organic solvent to prepare a mother solution with a concentration of 100 μmol / mL. Then, distilled pure water is added to dilute it to 1~5 μmol / L according to the required concentration.

[0037] 2. Fruit light treatment

[0038] The fruits treated with the drug were placed in the following environment for 5 days and photographed at 0d, 1d, 3d, and 5d:

[0039] ① Lighting conditions: The light source was 0.9 m above the fruit surface, and the artificial light source consisted of seven 18 W LED white light lamps (Ningbo Jiangnan Instrument Factory, China). The intensity of the white light on the pear fruit surface was 110 μmol•m -2 •s -1 (TES, 1332A, China);

[0040] ②Humidity conditions: relative humidity 80%;

[0041] ③Temperature conditions: 17℃.

[0042] Table 1 Composition of coloring accelerators in different treatment groups

[0043]

[0044] 3. Fruit color analysis

[0045] Figure 1 The following are photos of the coloration of the fruit skin of 'Hong Zao Su' pear fruits before treatment with different concentrations of EBL and after treatment for 1, 3, and 5 days. Compared with the control group, it can be found that after light treatment, the fruit skin of 'Hong Zao Su' pears accumulated anthocyanins, but by comparing the fruits after treatment for 3 and 5 days, it can be found that the fruit skin coloration was deeper and more uniform after treatment with different concentrations of EBL, and the effect of using 3 μmol / L EBL was better, but the coloring effect of the control group was poor.

[0046] Example 2

[0047] 1. Reagent processing

[0048] ① The red pear variety 'Hong Zao Su' was collected from the Zhengzhou Comprehensive Experimental Station of the National Pear Industry System in August 2024. The fruits were covered with light-proof double-layer fruit bags 40 days after full bloom until they reached physiological maturity. After the ripe fruits were harvested, they were immediately transported back to the laboratory, and the fruits of uniform size, without mechanical damage, cracking, disease, insects and rot were selected for processing.

[0049] ② The experiment was divided into two groups: a control group and a treatment group, as shown in Table 2. After soaking, the samples were placed in a light-proof environment to dry.

[0050] Table 2 Composition of coloring accelerators in different test groups

[0051]

[0052] 2. Fruit light treatment

[0053] Place the treated fruits in the following environment for 10 days:

[0054] ① Lighting conditions: The light source was 0.9 m above the fruit surface, and the artificial light source consisted of seven 18 W LED white light lamps (Ningbo Jiangnan Instrument Factory, China). The intensity of the white light on the pear fruit surface was 110 μmol·m -2 · s -1 (TES, 1332A, China);

[0055] ②Humidity conditions: relative humidity 80%;

[0056] ③Temperature conditions: 17℃.

[0057] 3. Determination of fruit indexes and sampling

[0058] After the treatment, the physiological indexes of the fruit were measured regularly, and then the peel of the illuminated part of the fruit was separated with a peeler, immediately placed in liquid nitrogen, and packaged into tubes according to the required amount of the measured index, and stored in a -80℃ refrigerator. The peel was used for the determination of anthocyanin content using spectrophotometry. The experiment was repeated in 3 groups, with 12 fruits in each group.

[0059] 4. Results Analysis

[0060] 4.1 Fruit color analysis

[0061] Figure 2 These are photos of the coloration of the fruit skin of the 'Hong Zao Su' pear before treatment and 10 days after treatment. Comparing the initial photos, it can be found that after 10 days of light treatment, the skin of the 'Hong Zao Su' pear has accumulated anthocyanins, but comparing the fruits 10 days after treatment, it can be found that the EBL coloring is significantly deeper and more uniform than the control, which improves the red stripe phenomenon of the 'Hong Zao Su' pear, but the coloring effect of the control group is poor.

[0062] like Figure 3 The results showed that after white light induction, the color parameters of the fruit surface near the light side of the EBL-treated and control fruits changed significantly. From the results of the significance analysis, the results of illumination (L) and a value showed that there was a significant difference between the skin of the 'Hong Zao Su' pears treated with EBL and the control (a represents the range from red to green, the higher the value, the darker the red, α=0.05, LSD test).

[0063] 4.2 Analysis of anthocyanin content in peel

[0064] like Figure 4 As shown in the figure, after white light treatment, the anthocyanin content of the fruit peel near the light side of the 'Hongzaosu' pear treated with EBL was different from that of the initial and control groups.

[0065] After the fruit was treated with EBL, anthocyanins from the peel were extracted using an extracting solution of hydrochloric acid: methanol = 1:99 (0.1 g sample was added to 500 μL of extracting solution). After centrifugation, the absorbance of the supernatant at wavelengths of 530 nm, 620 nm, and 650 nm was measured using a spectrophotometer. The calculation formula was: [(A530-A650)-0.2(A650-A620)] / weight.

[0066] 4.3 Analysis of fruit soluble solids

[0067] like Figure 5 As shown in the figure, after white light treatment, the soluble solids content of 'Hongzaosu' pear after EBL treatment was slightly increased compared with the initial content, but there was no significant difference compared with the control, indicating that EBL treatment did not reduce the intrinsic quality of pear fruit.

[0068] 4.4 Fruit firmness analysis

[0069] like Figure 6 As shown in the figure, the fruit firmness of both the EBL treatment group and the control group showed a downward trend after 10 days of treatment, but there was no significant difference compared with the control, which indicates that EBL treatment can not only improve the coloring degree of the fruit, but also effectively maintain the fruit firmness to a certain extent.

[0070] The above results showed that compared with the control, EBL treatment could significantly increase the content of anthocyanins in the peel of 'Hong Zao Su' pear, promote its coloring, and improve its appearance quality. At the same time, it could effectively maintain the intrinsic quality of 'Hong Zao Su' pear fruit and promote its promotion to a larger sales market.

[0071] Obviously, the above embodiments of the present invention are merely examples to more clearly illustrate the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A method for promoting the coloring of red pears using brassinolide, characterized in that: include: Red pears that have reached physiological maturity but have not yet colored are subjected to light coloring treatment. Before light exposure, the red pears are soaked in a soaking solution containing 24-epibrassinolide, wherein the concentration of 24-epibrassinolide in the soaking solution is 1-5 μmol / L, the soaking time is 5-30 min, and the soaking temperature is 4-35°C. The light coloring treatment is as follows: the red pears are soaked in a white light with an intensity of 50-120 μmol•m -2 •s -1 The mixture is allowed to stand for 5 to 10 days in an environment with a temperature of 15 to 20° C. and a relative humidity of 70 to 90%.

2. The method according to claim 1, characterized in that The red pears include red sand pears, red western pears and red hybrid pears.

3. The method according to claim 1, characterized in that: The concentration of 24-epibrassinolide in the soaking solution is 3 μmol / L, the soaking time is 15 min, and the soaking temperature is 25°C.

4. The method according to claim 1, characterized in that The soaking solution contains 0.1-0.5% by volume of a surfactant.

5. The method according to claim 4, characterized in that The surfactant is 0.2% by volume of Tween-20.

6. The method according to claim 1, characterized in that The white light intensity is 110 μmol•m -2 •s -1 .

7. The method according to claim 6, characterized in that The temperature is 17° C., and the relative humidity is 80%.

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