A method for preserving citrus fruits based on 10-undecenoic acid

Abstract

The application discloses a citrus fruit preservation method based on 10-undecenoic acid. The postharvest citrus is soaked in a preservative containing 10-undecenoic acid as an active ingredient, and then dried. The application finds through experiments that 10-undecenoic acid can significantly delay the rotting of sand sugar orange fruits, significantly delay the consumption of nutrients of the citrus fruits, and maintain better quality of the fruits. Therefore, 10-undecenoic acid can be used for postharvest disease prevention and preservation of fruits and vegetables, especially citrus fruits.

Description

Technical Field

[0001] This invention belongs to the field of fruit preservation, specifically relating to a method for preserving citrus fruits based on 10-undecenoic acid. Background Technology

[0002] Citrus fruits are the world's most popular fruit, widely cultivated in 125 countries and regions. my country ranks first in the world in both citrus cultivation area and yield. However, citrus fruits are difficult to preserve after harvest, and the rate of decay during transportation and storage can sometimes reach 50%, causing serious economic losses. Among these, fungal diseases such as Penicillium rot, Green mold, and Sour rot are the most prominent, and effective control methods are urgently needed.

[0003] Currently, post-harvest preservation of citrus mainly relies on chemical fungicides (such as imazalil and thiamethoxam). While these fungicides are effective in reducing fruit rot, long-term, high-volume, and frequent use can lead to environmental pollution, induce drug resistance in pathogens, and reduce or even eliminate their effectiveness. Furthermore, the residues of chemical fungicides pose a potential threat to human health. Therefore, developing safe and efficient preservation technologies is urgently needed.

[0004] 10-Undecenoic acid is an eleven-carbon single-chain unsaturated fatty acid containing a terminal double bond. It has a distinctive fruity aroma and is mainly found in natural plant oils such as avocado oil and pine nut oil. This compound combines the reactivity of the double bond with the acidity of the carboxyl group, making it widely used in high-value-added industries such as pharmaceuticals, cosmetics, industrial products, and food flavorings.

[0005] However, to date, there have been no reports on the application of 10-undecenoic acid in the prevention and control of postharvest diseases in fruits and vegetables. Summary of the Invention

[0006] The first objective of this invention is the application of 10-undecenoic acid in the preparation of citrus fruit preservatives.

[0007] The second objective of this invention is to provide a method for controlling postharvest diseases of citrus based on 10-undecenoic acid, which involves soaking postharvest citrus in a preservative containing 10-undecenoic acid as the active ingredient and then drying it.

[0008] Preferably, the preservative comprises, by weight parts, 1.0–2.0 parts 10-undecenoic acid, 0.2–0.5 parts Tween-80, 0.5–1.5 parts chitosan, and 1.0–2.0 parts glycerol, with water as the solvent.

[0009] More preferably, the content of 10-undecenoic acid is 0.01-0.5% by mass, and even more preferably 0.1% by mass.

[0010] Preferably, the soaking time is 0.5 minutes.

[0011] Preferably, after drying, it is packaged in a polyethylene film preservation bag for storage or transportation.

[0012] This invention, through experiments, has shown that 10-undecenoic acid can significantly delay the occurrence of decay in mandarin oranges, significantly slow down the consumption of nutrients in citrus fruits, and maintain good fruit quality. Therefore, 10-undecenoic acid can be used for postharvest disease prevention and preservation in fruits and vegetables, especially citrus fruits. Attached Figure Description

[0013] Figure 1 This invention illustrates the changes in the decay rate of mandarin oranges in the control and treatment groups during storage at room temperature.

[0014] Figure 2 This shows the changes in the decay index of mandarin oranges in the control and treatment groups during storage at room temperature.

[0015] Figure 3 This invention describes the changes in soluble solids content of mandarin oranges in the control and treatment groups during storage at room temperature.

[0016] Figure 4 This diagram illustrates the changes in titratable acid content of mandarin oranges in the control and treatment groups during storage at room temperature, as described in this invention. Detailed Implementation

[0017] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0018] Example 1: Preparation of a preservative based on 10-undecenoic acid

[0019] This embodiment provides a preservative for citrus fruits, comprising, by weight, 1.0–2.0 parts of 10-undecenoic acid, 0.2–0.5 parts of Tween-80, 0.5–1.5 parts of chitosan, and 1.0–2.0 parts of glycerol, with deionized water as the solvent.

[0020] The preparation method of this preservative includes the following steps:

[0021] (1) Oil phase preparation: Mix 10-undecenoic acid and Tween-80 at a mass ratio of 4:1 and stir evenly at room temperature;

[0022] (2) Aqueous phase preparation: Chitosan and glycerol are mixed at a mass ratio of 1:2 and then added to deionized water and stirred evenly at room temperature; chitosan needs to be dissolved in 1% glacial acetic acid solution in advance to prepare a chitosan solution with a mass fraction of 5%.

[0023] (3) Emulsification and homogenization: Under stirring conditions, the oil phase is slowly added to the aqueous phase, wherein 10-undecenoic acid and glycerol are in a mass ratio of 2:1. The mixture is stirred with a magnetic stirrer at a speed of 1000–1500 r / min for 10–15 minutes to obtain a homogeneous solution. Then, it is ultrasonically treated with 200 W for 5 minutes, and the pH is adjusted to 6.0–6.8 with a 15% KOH solution to obtain the preservative stock solution.

[0024] Example 2: Application of 10-Undecenoic acid-based preservatives in postharvest storage and preservation of citrus fruits

[0025] Select citrus fruits (variety: Satsuma mandarin) of uniform quality, size, maturity, and good appearance. Wash the outer peel with clean water and air dry naturally. Each treatment had 120 fruits, randomly divided into 3 replicates of 40 fruits each. The experimental setup was as follows: ① Control group CK1: soaked in clean water for 0.5 min; ② Positive control group CK2: soaked in 0.05% imazalil solution for 0.5 min; ③ Treatment group T1: soaked in 0.02% 10-undecenoic acid preservative solution (the preservative stock solution from Example 1 was diluted with water, the same below) for 0.5 min; ④ Treatment group T2: soaked in 0.1% 10-undecenoic acid preservative solution for 0.5 min; ⑤ Treatment group T3: soaked in 0.5% 10-undecenoic acid preservative solution for 0.5 min. After soaking, all fruits were air dried naturally, packaged in polyethylene film preservation bags, and stored in a ventilated warehouse at room temperature for 21 days.

[0026] (1) Determination of decay rate

[0027] Rot rate (%) = (Number of rotten fruits / Total number of fruits) × 100%. All fruits were periodically removed, and rotten fruits were picked out and counted. The result is expressed as the average rot rate of fruits from three replicate experiments.

[0028] (2) Determination of soluble solids and titratable acid content

[0029] Six fruits were collected from each group, and the juice was extracted from the mixture to obtain a mixed juice. This juice was used to determine the soluble solids and titratable acid content. Three biological replicates were set up for each group. The total soluble solids content was determined using a refractometer (PAL-1, Atago, Japan), and the results are expressed in °Brix. The titratable acid content was determined after diluting the juice concentrate 50 times.

[0030] Preservation effect:

[0031] The rotting of mandarin oranges in the control and treatment groups during storage at room temperature is shown in the figure. Figure 1Physical observation showed that, compared with the water control group (CK1), the 10-undecenoic acid preservative treatment significantly delayed the decay of Satsuma mandarin oranges, with treatment T2 showing the best effect, approaching the level of the positive control group (CK2). Figure 1 ).

[0032] Fruit rot rate directly reflects the storage characteristics of citrus fruits. Figure 2 It can be seen that the decay rate of citrus fruits gradually increased with the extension of storage time during storage. After 7 days of storage, the decay rate of the water control group (CK1) was 22.50%, while the decay rates of the different concentrations of 10-undecenoic acid treatment groups T1, T2, and T3 were 15.00%, 4.16%, and 5.83%, respectively, which were approximately 7.50%, 18.34%, and 16.67% lower than the control group. After 21 days of storage, the decay rate of the water control group reached 96.66%, while the decay rates of the T1, T2, and T3 groups were 79.16%, 59.16%, and 67.50%, respectively, which were approximately 17.50%, 37.50%, and 29.16% lower than the control group. Figure 2 The results further showed that 10-undecenoic acid treatment could significantly delay the occurrence of citrus fruit decay.

[0033] Soluble solids and titratable acid content are important indicators for evaluating fruit quality. Figure 3 and Figure 4 It can be seen that during storage, the soluble solids content and titratable acid content of the water control group (CK1) were significantly lower than those of each 10-undecenoic acid treatment group. After 7 days of storage, the soluble solids content of the water control group (CK1) was 11.36%, while the soluble solids content of the different concentrations of 10-undecenoic acid treatment groups T1, T2, and T3 were 12.16%, 14.06%, and 12.86%, respectively. Figure 3 After 21 days of storage, the titratable acid content of the water control group was 0.35%, and the decay rates of groups T1, T2, and T3 were 0.45%, 0.57%, and 0.53%, respectively. Figure 4 The results showed that 10-undecenoic acid treatment could significantly delay the consumption of nutrients in citrus fruits and maintain good fruit quality.

[0034] Example 3: Application of 10-Undecenoic acid-based preservatives in low-temperature cold storage preservation of citrus fruits

[0035] Select citrus fruits (variety: Satsuma mandarin) of uniform quality, size, maturity, and good appearance. Wash the peel with clean water and air dry naturally. Each treatment had 120 fruits, randomly divided into 3 replicates of 40 fruits each. The experimental setup was as follows: ① Control group: soaked in clean water for 0.5 min; ② Treatment group: soaked in a 0.1% (w / w) 10-undecenoic acid preservative solution for 0.5 min. After soaking, all fruits were air dried naturally, packaged in polyethylene film bags, and stored in a cold storage at 4–6℃ for 40 days.

[0036] Preservation effect:

[0037] After 40 days of storage, the fruit rot rate in the control group was approximately 20% (17.5%, 20%, and 20%, respectively), while the fruit rot rate in the treatment group was approximately 5% (5%, 7.5%, and 5%, respectively). The results indicate that treatment with 10-undecenoic acid preservative can significantly reduce the rot rate of citrus fruits during low-temperature refrigeration, demonstrating a good anti-corrosion and preservation effect.

Claims

1. Application of 1,10-Undecenoic acid in the preparation of citrus fruit preservatives.

2. A method for controlling postharvest diseases of citrus based on 10-undecenoic acid, characterized in that, The process involves soaking harvested citrus fruits in a preservative containing 10-undecenoic acid as the active ingredient, and then air-drying them.

3. The method according to claim 2, characterized in that, The preservative, by weight, comprises 1.0–2.0 parts of 10-undecenoic acid, 0.2–0.5 parts of Tween-80, 0.5–1.5 parts of chitosan, and 1.0–2.0 parts of glycerol, with water as the solvent.

4. The method according to claim 3, characterized in that, The content of 10-undecenoic acid is 0.01-0.5% by mass.

5. The method according to claim 4, characterized in that, The content of 10-undecenoic acid is 0.1% by mass.

6. The method according to claim 2, characterized in that, The soaking time is 0.5 minutes.

7. The method according to claim 2, characterized in that, After drying, pack and store or transport in polyethylene film bags.

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