Longtan pearl plum postharvest commercial processing and low temperature storage method

Abstract

The application discloses a post-harvest commercial treatment and low-temperature storage method of Longtan pearl plums, and belongs to the technical field of fruit preservation. The compound preservative solution prepared by compounding curcuma powder, dried tangerine peel powder and imazalil is combined with ultraviolet irradiation sterilization and low-temperature and high-humidity storage, so that the storage period of the Longtan pearl plum can be significantly prolonged, the fruit hardness can be maintained, and the rot rate can be greatly reduced. In addition, the application can also maintain good flavor and taste of the fruit, and avoid peculiar smell caused by excessive use of chemical preservatives; the protective film formed by the preservative solution and the high-humidity environment synergistically act, so that the fruit weight loss rate is effectively reduced. The method is simple in operation and low in cost, does not need complex air conditioning equipment, is suitable for popularization and application in the main producing area of the Longtan pearl plum, and has outstanding technical progress and practical value in prolonging the shelf life, inhibiting rotting and maintaining the appearance quality.

Description

Technical Field

[0001] This invention relates to the field of fruit preservation technology, and in particular to a method for the post-harvest commercial processing and low-temperature storage of Longtan Pearl Plum. Background Technology

[0002] Longtan Pearl Plum is a high-quality plum variety unique to Tian'e County, Guangxi Zhuang Autonomous Region. Its small, round fruit, purplish-red color, crisp and sweet taste, and rich nutrition make it highly popular with consumers, giving it significant economic value and market development potential. However, the ripening period of Longtan Pearl Plum is concentrated from late July to early August, coinciding with the hot and rainy season. After harvest, the fruit undergoes vigorous respiration and metabolism, making it highly susceptible to softening, wilting due to water loss, and rotting. Furthermore, the plum's thin, juicy skin makes it easily susceptible to pathogenic microorganisms after mechanical damage, resulting in a very short storage period—typically only a few days at room temperature. This severely restricts the commercial circulation of the fruit and hinders the improvement of industrial benefits.

[0003] Currently, common methods for postharvest preservation of plums mainly include low-temperature refrigeration, controlled atmosphere storage, chemical preservative treatment, and coating preservation. Low-temperature refrigeration can effectively inhibit fruit respiration, but simple low-temperature treatment is difficult to completely control pathogen growth, and long-term refrigeration can easily lead to chilling injury symptoms. Controlled atmosphere storage equipment is costly and complex to operate, making it unsuitable for small-scale producers. Chemical preservatives such as imazalil and prochloraz have good antibacterial effects, but long-term or excessive use may lead to pesticide residue risks, which does not meet the demand for green and safe products. Plant-derived extracts (such as turmeric and dried tangerine peel) have gradually become a research hotspot in the field of postharvest preservation due to their natural, low-toxicity, and biodegradable characteristics. However, single plant-derived components often have limited preservation effects, and there is a lack of systematic synergistic application research with physical treatment methods (such as ultraviolet irradiation).

[0004] Current technologies typically employ only single-agent immersion or ordinary cold storage for post-harvest processing of plums, lacking commercially viable treatment processes specifically for the Longtan Pearl Plum variety. In particular, they lack a comprehensive treatment method combining immersion in a compound plant-derived chemical preservative solution, ultraviolet sterilization, pre-cooling, and precise temperature and humidity storage. Therefore, developing a simple, safe, and efficient method suitable for the commercial post-harvest processing and low-temperature storage of Longtan Pearl Plums is crucial for extending fruit shelf life, maintaining superior quality, and reducing post-harvest losses. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the post-harvest commercial processing and low-temperature storage of Longtan pearl plums, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a method for post-harvest commercial processing and low-temperature storage of Longtan pearl plums, comprising the following steps: (1) Soak the harvested fruit in a compound preservation solution, take it out and dry it, and then sterilize it by ultraviolet irradiation. (2) Pack the sterilized fruits into portions and pre-cool them so that the core temperature reaches 2℃~3℃; (3) Transfer the pre-cooled fruit to a storage warehouse for low-temperature storage; The compound preservative solution contains turmeric powder, dried tangerine peel powder, and imidacloprid.

[0007] Based on the above technical solution, the present invention has the following technical effects: This invention utilizes a compound preservative solution made from turmeric powder, dried tangerine peel powder, and imazalil, combined with ultraviolet sterilization and low-temperature, high-humidity storage. This significantly extends the storage period of Longtan Pearl Plums while maintaining fruit firmness. In Example 2, after 21 days of storage, the firmness still reached 438.33 g, while in Comparative Example 1, which was not treated with the preservative solution, the firmness was only 273.00 g. g; it also significantly reduces the decay rate. In Examples 1 and 2, no fruit decayed, and the decay rate was much lower than that of Comparative Example 1 (6.67%) without the use of preservative solution and Comparative Example 3 (41.11%) stored at room temperature. In addition, the present invention can maintain the good flavor and taste of the fruit. The flavor score of Example 1 reached 8.56 points (out of 10), avoiding the off-flavors caused by excessive use of chemical preservatives. Through the synergistic effect of the protective film formed by the preservative solution and the high humidity environment, the weight loss rate of the fruit is effectively reduced. The weight loss rate of Example 2 was only 1.12%, which was much lower than that of Comparative Example 1 (3.51%), Comparative Example 2 (3.22%) and Comparative Example 3 (15.49%). The method of the present invention is simple to operate, low in cost, and does not require complex modified atmosphere equipment. It is suitable for promotion and application in the main production area of ​​Longtan Pearl Plum. It has outstanding technical progress and practical value in extending shelf life, inhibiting decay, and maintaining appearance quality. Detailed Implementation

[0008] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods used in the embodiments are conventional methods, and the reagents used are commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0009] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0010] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0011] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0012] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0013] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0014] This invention provides a method for the post-harvest commercial processing and low-temperature storage of Longtan pearl plums, comprising the following steps: (1) Soak the harvested fruit in a compound preservation solution, take it out and dry it, and then sterilize it by ultraviolet irradiation. (2) Pack the sterilized fruits into portions and pre-cool them so that the core temperature reaches 2℃~3℃; (3) Transfer the pre-cooled fruit to a storage warehouse for low-temperature storage; The compound preservative solution contains turmeric powder, dried tangerine peel powder, and imidacloprid.

[0015] In some specific implementation schemes, the concentration of turmeric powder in the compound preservative solution is 0.5–1.5 g / L, the concentration of dried tangerine peel powder is 1.0–3.0 g / L, and the concentration of imidacloprid is 0.5–1.5 g / L.

[0016] In some specific implementation schemes, the compound preservative solution is pre-cooled to 15-20°C before use; the fruit soaking time is 3-5 minutes.

[0017] In some specific implementations, the ultraviolet irradiation time is 10 to 15 minutes.

[0018] In some specific implementations, the repackaging is done in boxes of 5 to 10 kg.

[0019] In some specific implementations, the temperature of the low-temperature storage warehouse is 0℃~3℃, and the relative humidity is 90%~95%.

[0020] Example 1 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70% to 80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is harvested by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0021] 1. Soak the harvested fruit 1.1 Preparation of compound preservative solution To prepare a compound preservative solution containing 1.0 g / L turmeric powder, 2.0 g / L dried tangerine peel powder, and 1.0 g / L imidacloprid: First, soak the turmeric powder and dried tangerine peel powder in a small amount of warm water (50-60℃) for 30 minutes to prepare a mother liquor, then filter to remove the residue. Next, mix the mother liquor with an imidacloprid aqueous solution and dilute with water to the required concentration.

[0022] 1.2 Pre-cool the compound preservative solution to 15°C, then immerse the harvested fruit in the compound preservative solution for 5 minutes. After immersion, remove the fruit and arrange them in layers on a shelf to air dry. After air drying, sterilize by irradiating with ultraviolet light for 10 minutes.

[0023] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 10 kg boxes. After packaging, they are pre-cooled until the core temperature reaches 2℃~3℃. The pre-cooled fruits are then transferred to a storage warehouse with a cold storage temperature of 0℃~3℃ and a humidity of 90%~95%.

[0024] Example 2 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70% to 80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is harvested by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0025] 1. Soak the harvested fruit 1.1 Preparation of compound preservative solution To prepare a compound preservative solution containing 1.5 g / L turmeric powder, 3.0 g / L dried tangerine peel powder, and 1.5 g / L imidacloprid: First, soak the turmeric powder and dried tangerine peel powder in a small amount of warm water (50-60℃) for 30 minutes to prepare a mother liquor, then filter to remove the residue. Next, mix the mother liquor with an imidacloprid aqueous solution and dilute with water to the required concentration.

[0026] 1.2 Pre-cool the compound preservative solution to 20°C, then immerse the harvested fruit in the compound preservative solution for 3 minutes. After immersion, remove the fruit and arrange it in layers on a shelf to air dry. After air drying, sterilize by irradiating with ultraviolet light for 15 minutes.

[0027] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 5 kg boxes. After packaging, the fruits are pre-cooled until the core temperature reaches 2℃~3℃. The pre-cooled fruits are then transferred to a storage warehouse with a cold storage temperature of 0℃~3℃ and a humidity of 90%~95%.

[0028] Example 3 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70% to 80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is harvested by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0029] 1. Soak the harvested fruit 1.1 Preparation of compound preservative solution To prepare a compound preservative solution containing 0.5 g / L turmeric powder, 1.0 g / L dried tangerine peel powder, and 0.5 g / L imidacloprid: First, soak the turmeric powder and dried tangerine peel powder in a small amount of warm water (50-60℃) for 30 minutes to prepare a mother liquor, then filter to remove the residue. Next, mix the mother liquor with an imidacloprid aqueous solution and dilute with water to the required concentration.

[0030] 1.2 Pre-cool the compound preservative solution to 20°C, then immerse the harvested fruit in the compound preservative solution for 5 minutes. After immersion, remove the fruit and arrange it in layers on a shelf to air dry. After air drying, sterilize by irradiating with ultraviolet light for 10 minutes.

[0031] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 5 kg boxes. After packaging, the fruits are pre-cooled until the core temperature reaches 2℃~3℃. The pre-cooled fruits are then transferred to a storage warehouse with a cold storage temperature of 0℃~3℃ and a humidity of 90%~95%.

[0032] Comparative Example 1 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70-80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is picked by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0033] 1. After harvesting, place the fruits in layers on the shelf and sterilize them by irradiating them with ultraviolet light for 10 minutes.

[0034] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 10 kg boxes. After packaging, they are pre-cooled until the core temperature reaches 2℃~3℃. The pre-cooled fruits are then transferred to a storage warehouse with a cold storage temperature of 0℃~3℃ and a humidity of 90%~95%.

[0035] Comparative Example 2 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70% to 80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is harvested by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0036] 1. Soak the harvested fruit 1.1 Preparation of compound preservative solution To prepare a compound preservative solution containing 1.0 g / L turmeric powder, 2.0 g / L dried tangerine peel powder, and 1.0 g / L imidacloprid: First, soak the turmeric powder and dried tangerine peel powder in a small amount of warm water (50-60℃) for 30 minutes to prepare a mother liquor, then filter to remove the residue. Next, mix the mother liquor with an imidacloprid aqueous solution and dilute with water to the required concentration.

[0037] 1.2 Pre-cool the compound preservative solution to 15°C, then immerse the harvested fruit in the compound preservative solution for 5 minutes. After immersion, remove the fruit and arrange it in layers on a shelf to dry.

[0038] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 10 kg boxes. After packaging, they are pre-cooled until the core temperature reaches 2℃~3℃. The pre-cooled fruits are then transferred to a storage warehouse with a cold storage temperature of 0℃~3℃ and a humidity of 90%~95%.

[0039] Comparative Example 3 When the Longtan Pearl Plum is seven to eight tenths ripe, the base color of the fruit turns red, and the colored area of ​​the fruit surface reaches 70% to 80%. It is harvested in the early morning after the dew has dried or in the evening, avoiding the high temperature period. It is harvested by hand, retaining the fruit stem, and removing diseased, insect-damaged, mechanically damaged, overripe, and deformed fruits.

[0040] 1. Soak the harvested fruit 1.1 Preparation of compound preservative solution To prepare a compound preservative solution containing 1.0 g / L turmeric powder, 2.0 g / L dried tangerine peel powder, and 1.0 g / L imidacloprid: First, soak the turmeric powder and dried tangerine peel powder in a small amount of warm water (50-60℃) for 30 minutes to prepare a mother liquor, then filter to remove the residue. Next, mix the mother liquor with an imidacloprid aqueous solution and dilute with water to the required concentration.

[0041] 1.2 Pre-cool the compound preservative solution to 15°C, then immerse the harvested fruit in the compound preservative solution for 5 minutes. After immersion, remove the fruit and arrange them in layers on a shelf to air dry. After air drying, sterilize by irradiating with ultraviolet light for 10 minutes.

[0042] 2. Cold storage pre-cooling After sterilization, the fruits are packaged into 10 kg boxes and stored at room temperature.

[0043] Example of effect For plum fruits treated in Examples 1-3 and Comparative Examples 1-3, samples were taken weekly to test fruit firmness, decay rate, flavor and texture, and weight loss. Firmness was measured repeatedly 6 times, flavor and texture were evaluated repeatedly 8 times, and decay rate and weight loss were measured repeatedly 3 times. Results are expressed as mean ± standard deviation. DPS software was used for significance analysis (Duncan's new multiple range method). P <0.05 indicates a significant difference. Typical test results at day 21 (3 weeks) of storage are shown in Table 1.

[0044] The results are shown in Table 1.

[0045] Table 1

[0046] Note: Different lowercase letters in the same column indicate significant differences. P <0.05).

[0047] As shown in Table 1: Firmness: The fruit from Example 2 had the highest firmness (438.33 g), significantly higher than that from Examples 1 and 3, and all comparative examples. P <0.05). Comparative Example 3 (stored at room temperature) had a hardness of only 118.50 g, indicating severe softening of the fruit. This demonstrates that using a high concentration of compound preservative solution (1.5 g / L turmeric powder, 3.0 g / L dried tangerine peel powder, and 1.5 g / L imidacloprid) combined with ultraviolet sterilization and low-temperature storage can most effectively inhibit fruit softening.

[0048] Rot rate: The fruits in Examples 1 and 2 showed no rot after 21 days of storage, while the rot rate in Example 3 was only 1.11%. The rot rates of the fruits in Comparative Examples 1 and 2 were significantly higher, while the rot rate in Comparative Example 3 was as high as 41.11%, significantly higher than the other treatment groups. P (<0.05), almost losing its commercial value. This indicates that soaking in the compound preservative solution and ultraviolet irradiation have a synergistic antibacterial effect, and neither can be omitted.

[0049] Flavor and texture: Example 1 had the highest flavor and texture score (8.56 points), significantly better than Example 2, Example 3, and Comparative Examples 1-3. P<0.05). Although Example 2 showed the best preservation effect, the higher concentrations of turmeric, dried tangerine peel, and imazalil may have resulted in a slightly bitter taste, thus the taste score was slightly lower than that of Example 1. Comparative Example 3 had a very poor flavor (1.94 points), a soft texture, and a noticeable putrid odor.

[0050] Weight loss rate: Example 2 had the lowest weight loss rate (1.12%), followed by Example 1 (1.17%), both significantly lower than Comparative Example 1 (3.51%), Comparative Example 2 (3.22%), and Comparative Example 3 (15.49%). P <0.05). This indicates that the protective film formed on the fruit surface by the compound preservative solution can effectively reduce water transpiration, and the low temperature and high humidity environment further reduces weight loss.

[0051] In summary, Examples 1-3 all significantly extended the storage period of Longtan Pearl Plums while maintaining good quality. Example 2 showed the best performance in maintaining firmness, preventing spoilage, and reducing weight, making it suitable for long-term storage; Example 1 demonstrated superior flavor and taste retention. Comparative Examples 1-3, lacking key steps such as soaking in a compound preservative solution, ultraviolet sterilization, or low-temperature storage, experienced a significant decline in fruit quality. Therefore, the post-harvest commercial processing and low-temperature storage method for Longtan Pearl Plums provided by this invention has outstanding technical effects and practical value.

[0052] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for the post-harvest commercial processing and low-temperature storage of Longtan pearl plums, characterized in that, Includes the following steps: (1) Soak the harvested fruit in a compound preservation solution, take it out and dry it, and then sterilize it by ultraviolet irradiation. (2) Pack the sterilized fruits into portions and pre-cool them so that the core temperature reaches 2℃~3℃; (3) Transfer the pre-cooled fruit to a storage warehouse for low-temperature storage; The compound preservative solution contains turmeric powder, dried tangerine peel powder, and imidacloprid.

2. The method according to claim 1, characterized in that, In the compound preservative solution, the concentration of turmeric powder is 0.5–1.5 g / L, the concentration of dried tangerine peel powder is 1.0–3.0 g / L, and the concentration of imidacloprid is 0.5–1.5 g / L.

3. The method according to claim 1, characterized in that, The compound preservative solution is pre-cooled to 15-20°C before use; the fruit soaking time is 3-5 minutes.

4. The method according to claim 1, characterized in that, The ultraviolet irradiation time is 10 to 15 minutes.

5. The method according to claim 1, characterized in that, The repackaging is 5-10 kg per box.

6. The method according to claim 1, characterized in that, The temperature of the low-temperature storage warehouse is 0℃~3℃, and the relative humidity is 90%~95%.

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