Application of indole-3-acetamide in postharvest storage and preservation of citrus
Indole-3-acetamide is used as auxin analog for citrus storage and preservation, solving the problems of IAA instability and 2,4-D environmental risks, and achieving efficient preservation and quality maintenance of fruits.
Patent Information
- Application Number
- CN202510531365.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-08-19
AI Technical Summary
The existing auxin IAA has no significant effect and is unstable in preserving citrus. Chemical synthetic analogues 2,4-D have environmental risks, and green and efficient preservatives need to be developed.
Indole-3-acetamide is used as auxin analog, which is used for storage and preservation of citrus after harvesting, soaking the fruits naturally drying and storing, and the concentration is 50-500 mg/L, preferably 200 mg/L.
Significantly reduce the aging rate and rot rate of the pedicle, inhibit the accumulation of reactive oxygen species, improve SOD activity, maintain the hardness and sugar-acid ratio of fruit, prolong the storage period, and maintain the quality of the fruit.
Smart Images
Figure CN120501145A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of food preservation, and particularly relates to application of indole-3-acetamide in storage and preservation of post-harvest citrus. Background Art
[0002] Auxin (IAA) is an important hormone in plants and plays a vital role in the growth and development of plants. It participates in the life processes of plant cells, such as elongation and division, growth of primary and lateral roots and hypocotyls, formation of plant geotropism and phototropism, and formation of root hairs and floral organs. It is of great significance to the early growth and development and morphological construction of plants. In addition, in terms of post-harvest preservation, IAA can improve the commercial value of fruits by delaying fruit decay, improving fruit resistance and maintaining fruit nutrients. Ma Qiaoli (2014) used Wenzhou mandarin orange "Owari" ( Citrus Unshiu Owari) was used as the material. By measuring the physiological indicators of the fruits after IAA treatment, such as decay rate, weight loss rate, hardness, titrated acidity, and soluble solids, it was found that IAA has a certain antiseptic and fresh-keeping effect on citrus fruits.
[0003] Indole-3-acetic acid (IAA), a natural auxin, plays a vital role in plant growth and development. However, IAA is chemically unstable, particularly under light conditions, and readily decomposes into 3-methyleneoxyindole and indolealdehyde, severely impacting its biological activity. In aqueous solution, the photodecomposition of IAA accelerates. In the presence of natural pigments such as riboflavin or violaxanthin, these pigments absorb blue light and accelerate the photooxidation of IAA.
[0004] Given that IAA is not very effective in preserving citrus fruits, the development of a more efficient auxin analog preservative is particularly important. 2,4-Dichlorophenoxyacetic acid (2,4-D), a synthetic auxin analog, is widely used as a preservative in post-harvest storage of citrus fruits. By mixing it with a fungicide to form a solution and soaking the fruit, it effectively keeps the fruit stems fresh, slows aging, and significantly extends the storage period. However, the production process of 2,4-D may produce dioxins, a harmful intermediate. Their high carcinogenicity, long half-life, and difficulty in degrading in soil pose a long-term potential risk to the ecological environment. For this reason, the European Union has banned the use of 2,4-D in the field of green food preservation, and the trend towards its ban is becoming increasingly apparent worldwide.
[0005] In this context, it is particularly urgent to develop green and efficient preservatives, which is of great practical significance for ensuring the sustainable development of the citrus industry and meeting consumers' demand for green food. Summary of the Invention
[0006] The purpose of the present invention is to provide a new use of indole-3-acetamide in the post-harvest storage and preservation of citrus.
[0007] To achieve the above objectives, the applicant first selected a variety of indole-3-acetic acid analogs, including indole-3-acetamide, indole-3-acetate methyl ester, and indole-3-ethylamine, and conducted post-harvest storage and preservation tests using Wogan oranges as the experimental material. The applicant identified indole-3-acetamide as having stronger preservative activity, significantly extending the storage life of citrus. Next, the applicant used Wenzhou mandarin oranges as the experimental material to further verify the role of indole-3-acetamide in citrus preservation, confirming that indole-3-acetamide can significantly reduce the senescence and decay rate of fruit stems; inhibit the accumulation of reactive oxygen species (ROS) in the peel and increase superoxide dismutase (SOD) activity; and maintain fruit firmness, soluble solids, and sugar-acid ratio, thereby preserving its inherent quality.
[0008] Therefore, indole-3-acetamide, as an indole-3-acetic acid analogue, has excellent post-harvest storage and preservation effects on citrus fruits.
[0009] When treating citrus fruits with indole-3-acetamide solution, the concentration of the indole-3-acetamide solution is 50-500 mg / L, preferably 200 mg / L. The treatment method includes soaking the citrus fruits in the indole-3-acetamide solution for 1-5 minutes, then naturally drying and storing.
[0010] The beneficial effects of the present invention are: Indole-3-acetamide is a synthetic auxin analogue widely used as a pharmaceutical intermediate. As an upstream product in the tryptophan synthesis pathway of auxin (IAA), indole-3-acetamide is widely present in plants and, as a natural product, poses minimal risks to humans and the environment. Upon absorption by plants, indole-3-acetamide may be hydrolyzed by indole-3-acetamide hydrolase into auxin, further regulating plant growth. Furthermore, this raw material is inexpensive.
[0011] The senescence rate of the citrus fruit stalks after treatment with the present invention is not significantly different from that after treatment with 2,4-D, and is lower than that after treatment with pure water, indicating that the present invention can effectively delay the senescence of the fruit stalks and achieve the effect of extending the storage period of citrus. The hardness, weight loss, color difference, soluble solids, and titratable acid of the citrus treated with the present invention are not significantly different from those with 2,4-D and pure water, indicating that the present invention has no adverse effect on the quality of the citrus fruit after treatment with the fruit stalks and can better maintain the intrinsic quality of the citrus fruit. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 : The senescence rate of the pedicle of the mandarin orange fruit after being treated with different preservatives in Example 1; Figure 2: The senescence rate of the pedicel of the mandarin orange fruit after the preservative treatment in Example 2; Figure 3 : The rot rate of Wenzhou mandarin orange fruit after the preservative treatment in Example 2; Figure 4 : Changes in ROS in the peel of Wenzhou mandarin orange fruit after treatment with the preservative in Example 2; Figure 5 : Changes in appearance of the pedicles of the mandarin orange fruits after treatment with the preservative in Example 2. DETAILED DESCRIPTION
[0013] The following describes the technical solutions in the implementation cases of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0014] In the following examples, the fruit pedicle senescence rate is expressed as the percentage of fruits with senescent pedicles in the late storage period to the total number of fruits. The fruit rot rate is expressed as the percentage of fruits with rotten pedicles in the late storage period to the total number of fruits. Data were processed using Excel, and significance analysis was performed using SPSS software (P < 0.05). Bar graph labels (e.g., a, b, c, etc.) indicate significance.
[0015] The structure and molecular formula of indole-3-acetamide are as follows: Chinese name: Indole-3-acetamide; English name: Indole-3-acetamide; Molecular formula: C 10 H 10 N2O molecular weight: 174.20; CAS number: 879-37-8
[0016] Example 1: Discovery of indole-3-acetamide in postharvest storage and preservation of citrus fruits Citrus storage preservative screening experiment: To develop other green and safe chemical preservatives, we selected a variety of indole-3-acetic acid analogs, including indole-3-acetamide, indole-3-acetic acid methyl ester, and indole-3-ethylamine. Water was used as a control treatment, and 2,4-dichlorophenoxyacetic acid was used as a positive control. Mandarin oranges were selected as the experimental material. The post-harvest storage experimental steps are as follows: 1. Solution preparation: Weigh the solid powder of the above five drugs separately, add a certain volume of cosolvent (such as 5% ethanol) to prepare a 200 mg / L solution.
[0017] 2. Experimental treatment: Select Wogan fruits of uniform size and color, soak them in the above solution and water for 2 minutes respectively, dry them naturally, put them in bags, and then store them at room temperature for 1 month.
[0018] 3. The experimental results are as follows: Figure 1 This figure shows the senescence rate of pedicles of postharvest Wogan fruit during storage. Treatment abbreviations and codes: CK: water; IAA: indole-3-acetic acid; TRY: indole-3-ethylamine; IMA: indole-3-acetate methyl ester; IAM: indole-3-acetamide; 2,4-D: 2,4-D sodium salt.
[0019]
[0020] from Figure 1 As shown, IAA had a poor effect on postharvest preservation of citrus fruits. From the 14th day onward, its fruit pedicle senescence rate was not significantly different from that of the water control treatment (p>0.05). The TRY and IMA treatments showed no significant difference in fruit pedicle senescence from the 21st day onward (p>0.05). However, the IAM treatment slowed fruit pedicle senescence until the 28th day, with an effect comparable to that of 2,4-D. This suggests that among all indole-3-acetic acid analogs, IAM has a stronger postharvest preservation activity for citrus fruits and can significantly extend the storage life of citrus fruits.
[0021] Example 2: Application of indole-3-acetamide in post-harvest storage and preservation of Wenzhou mandarin oranges 1. Solution preparation: Weigh indole-3-acetamide solid powder and 2,4-D sodium salt solid powder separately, add a certain volume of cosolvent (such as ethanol, such as 5% ethanol) to prepare a 200 mg solution.
[0022] 2. Experimental treatment: Select Wenzhou mandarin oranges of uniform size and color, soak them in the above solution and water for 2 minutes respectively, dry them naturally, put them in bags, and then store them at room temperature for 1 month.
[0023] 3. The experimental results are as follows: Figure 2 It shows the senescence rate of the fruit pedicles of Wenzhou mandarin oranges during post-harvest storage; Figure 3 Shows the decay rate of Wenzhou mandarin orange fruit during post-harvest storage; Figure 4 It shows the changes of ROS in the peel of Wenzhou mandarin orange fruit during postharvest storage; Figure 5 Shows the appearance of the fruit pedicles of Wenzhou mandarin oranges during post-harvest storage.
[0024] from Figure 2 、 Figure 3It can be seen that the fruit decay rate and fruit pedicle senescence rate of Wenzhou mandarin oranges treated with 200 mg / L 2,4-D and IAM at 14, 21 and 28 days after harvest were significantly lower than those in the clear water control (p<0.05).
[0025] from Figure 4 It can be seen that after 21 days of post-harvest storage of Wenzhou mandarin oranges, IAM and 2,4-D treatments can significantly reduce [O2] - The accumulation of reactive oxygen species may alleviate the damage caused by this reactive oxygen species; and the superoxide dismutase (SOD) activity in IAM-treated fruits was significantly higher than that in control fruits at the beginning of storage; except for the 7th day after treatment, the peroxidase (POD) activity in IAM-treated fruits was lower than that in control fruits.
[0026] In addition, the experiment measured that the titratable acid content of Wenzhou mandarin treated with CK, 2,4-D and IAM after 30 days was 0.41, 0.45 and 0.38, respectively, the soluble solids were 11.06, 10.09 and 10.60, respectively, and the sugar-acid ratio was 27.00, 22.73 and 28.58, respectively, indicating that indole-3-acetamide treatment would not affect the intrinsic quality of Wenzhou mandarin fruit.
[0027] The above experimental results show that the senescence rate and rot rate of the citrus fruit stems treated with the present invention are significantly lower than those treated with the water control. Moreover, the IAM treatment can not only reduce the activity of SOD by inducing [O2] - content, and can also increase H2O2 levels by inhibiting POD activity, thereby alleviating [O2] - damage and enhance the fruit's disease resistance mediated by H2O2. This shows that the present invention can keep the fruit stem green and fresh, effectively alleviate the aging of the fruit stem, and extend the storage period of the fruit. Although indole-3-acetate methyl ester and indole-3-ethylamine show a fresh-keeping effect in the early stage of storage, the fresh-keeping effect is not long-lasting. In addition, the soluble solids and titratable acid of the citrus fruits treated with the present invention after harvest have no significant differences compared with 2,4-D and water, and the hardness is significantly higher than that of the clear water control treatment, indicating that the present invention has no adverse effects on the fruits after treating mature citrus fruits.
[0028] The above description is only a preferred example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. Application of indole-3-acetamide in post-harvest storage and preservation of citrus.
2. The use according to claim 1, characterized in that: The indole-3-acetamide enhances the disease resistance of the fruit by inhibiting the accumulation of reactive oxygen species (ROS) in the peel, increasing the activity of superoxide dismutase (SOD), and reducing the activity of peroxidase (POD).
3. A method for storing and preserving citrus fruits after harvest, characterized in that: Treating citrus fruits with an effective concentration of indole-3-acetamide solution can delay fruit stalk aging, reduce the decay rate, and maintain fruit quality.
4. The method according to claim 3, wherein: The concentration of the indole-3-acetamide solution is 50-500 mg / L.
5. The method according to claim 4, wherein: The concentration of the indole-3-acetamide solution is 200 mg / L.
6. The method according to claim 3, wherein: The treatment method comprises soaking the citrus fruits in an indole-3-acetamide solution for 1-5 minutes, and then naturally drying and storing the fruits.