Method for preventing and treating blackheart disease after pineapple picking

Abstract

The invention relates to a method for preventing and treating postharvest blackheart disease of pineapples. The method comprises the following steps: storing postharvest pineapple fruits at a low temperature of 4-10 DEG C for 10-14 days; performing high-temperature storage on the pineapple fruits subjected to low-temperature storage at the temperature of 35-38 DEG C for 3-5 days; and storing the pineapple fruits after high-temperature storage at room temperature. According to the method disclosed by the invention, the occurrence of the blackheart disease caused by refrigeration after pineapple picking can be effectively prevented, the shelf life of fruits is prolonged, and the incidence rate of the blackheart disease can be greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fruit preservation, relates to a method for fruit preservation and storage, and specifically relates to a method for preventing and treating post-harvest blackheart disease of pineapples. Background Art

[0002] As an important representative of tropical fruits, pineapple (Ananas comosus (L.)) occupies a prominent position in the agricultural economy of southern my country and is one of the main export-earning fruits. Its unique flavor and rich nutritional value make it popular in domestic and foreign markets. Pineapple "Bali" (Ananas comosus'Comtede Paris') is the main pineapple variety grown in southern China, accounting for more than 90% of China's total pineapple production.

[0003] However, pineapple fruit is not tolerant to low temperatures, which has become a key bottleneck restricting the high-quality development of the pineapple industry during post-harvest cold storage. With the widespread application of modern cold chain logistics technology, low-temperature storage / cold chain logistics has become the main mode of export and long-distance transportation of pineapples after harvest, but long-term (more than 1 week) low-temperature refrigeration environment will inevitably cause serious physiological damage to pineapple fruits, among which the chilling injury phenomenon is particularly prominent, manifested as the occurrence of black heart disease.

[0004] Generally speaking, when pineapples are stored at low temperatures, the physiological metabolic processes inside the fruit are inhibited by the low temperature. However, when the fruit is stored at low temperatures for a long time and reaches its shelf life, it often suffers from chilling damage, which aggravates the aging and death of cells at room temperature. These physiological changes are ultimately reflected in the appearance of the fruit as black heart symptoms. This black heart disease not only seriously affects the appearance quality of the pineapple and reduces its commodity value, but also leads to the loss of nutrients inside the fruit and the deterioration of the flavor, greatly shortening the shelf life and market sales radius of the pineapple, causing huge economic losses to growers, distributors and the entire pineapple industry.

[0005] At present, although there have been some studies and explorations on the problem of post-harvest chilling injury of pineapples, there is no comprehensive, efficient and easy-to-implement solution that can effectively solve the chilling injury problem of pineapples during cold storage and meet the urgent needs of the industry for extending the shelf life of pineapples, maintaining fruit quality and reducing economic losses. Therefore, developing an innovative technical method that can effectively reduce or prevent post-harvest chilling injury of pineapples has extremely important practical significance and economic value, which has also become the key technical problem that this application aims to solve. Summary of the invention

[0006] In view of the above problems, the object of the present invention is to provide a composition and method for controlling the browning of the heart of post-harvest pineapples, which can effectively prevent the occurrence of pineapple blackheart disease, and has high repeatability and is easy to promote and apply in production.

[0007] According to one aspect of the present invention, a method for preventing and controlling post-harvest blackheart disease of pineapples is provided, comprising the following steps: storing the harvested pineapple fruits at a temperature of 4 to 10°C for 10 to 14 days; storing the pineapple fruits after low-temperature storage at a temperature of 35 to 38°C for 3 to 5 days; and storing the pineapple fruits after high-temperature storage at room temperature.

[0008] According to one embodiment, the method further comprises pre-treating the harvested pineapple fruit in advance; the pre-treating comprises spraying a pre-treating composition onto the surface of the pineapple fruit so that the surface of the pineapple fruit is completely wetted. The pre-treating composition comprises at least two of proline, aminobutyric acid and aspartic acid.

[0009] Preferably, the pretreatment composition comprises 3.5-4 g / L of proline, 80-100 mg / L of γ-aminobutyric acid, and 5-8 g / L of aspartic acid.

[0010] Preferably, the pretreatment composition further comprises 0.008-0.012% Tween 80.

[0011] According to another embodiment, the method further comprises post-treatment between high temperature storage and room temperature storage, wherein the post-treatment comprises fumigating the pineapple fruit after high temperature storage with a 400-500 ppb 1-methylcyclopropene aqueous solution for 11-13 hours.

[0012] According to another embodiment, the method further comprises sterilizing the pineapple with a 0.9-1.0 mL / L aqueous solution of prochloraz.

[0013] Preferably, the sterilization step comprises soaking the stalks of the harvested pineapple fruits with a 0.9-1.0 mL / L aqueous solution of prochloraz, or harvesting the pineapples with a utensil coated with the aqueous solution of prochloraz.

[0014] The method according to the present invention can effectively prevent the occurrence of black heart disease caused by cold storage of pineapples after harvest, extend the shelf life of the fruit, and significantly reduce the incidence of black heart disease. DETAILED DESCRIPTION

[0015] It is well known in the art that pineapples are not resistant to low temperatures, but low-temperature cold chain storage is still the main means of storage and transportation of pineapples after harvest. The method according to the present invention is used to control the problem of black heart disease caused by post-harvest pineapple fruits during low-temperature refrigeration, so as to effectively prevent and control black heart disease and extend the shelf life.

[0016] The present invention provides a method for preventing and controlling post-harvest blackheart disease of pineapples, which may include a low-temperature storage step, a high-temperature storage step and a normal-temperature storage step, for example, the method may consist of a low-temperature storage step, a high-temperature storage step and a normal-temperature storage step.

[0017] In order to ensure that the pineapple fruit still maintains a good appearance, excellent taste and rich nutrients after harvesting, storage, transportation and shelf life, the pineapple fruit needs to be stored at a low temperature of 4 to 10 degrees Celsius (also known as refrigeration). Generally speaking, as the temperature decreases, the respiration of the pineapple fruit decreases, the consumption rate of nutrients such as sugar and vitamins in the pineapple fruit slows down, and the growth of microorganisms is inhibited, which can extend the storage time and freshness of the pineapple, so that it can be supplied to the market or eaten by consumers during a longer shelf life.

[0018] The low temperature storage step may include storing the harvested pineapple fruits at a temperature of 4-10°C, preferably 5-8°C, such as 5°C, 6°C or 7°C for 10-15 days, such as 11 days, 12 days, 13 days or 14 days.

[0019] The high temperature storage step comprises storing the pineapple fruit after low temperature storage at a temperature of 35 to 38° C. (eg 36° C. or 37° C.) for 3 to 5 days.

[0020] After low-temperature storage, the cell structure of pineapple fruit usually suffers a certain degree of low-temperature damage, such as phase change of cell membrane and reduced fluidity. This change will cause cell energy loss and the generation of a large number of free radicals, leading to membrane lipid peroxidation and accumulation and oxidation of phenolic substances, thereby inducing the occurrence of black heart disease. In the high-temperature storage step, on the one hand, the fluidity of the cell membrane of pineapple fruit increases, and the low-temperature damage can be restored or adjusted, thereby alleviating the occurrence of black heart disease; on the other hand, at a temperature of 35-38°C, the physiological activities of pineapple fruit such as respiration that are inhibited in the low-temperature storage step can be accelerated again, and this temperature range is close to the suitable temperature for the natural ripening of pineapples, and the pineapple fruit will undergo a ripening process, which is conducive to the synthesis of flavor substances in the pineapple fruit, making the pineapple fruit more fragrant and sweeter in taste.

[0021] The above-mentioned room temperature storage step includes storing the pineapple fruit after high temperature storage at room temperature, for example, storing it at 20-25° C. After the above-mentioned low temperature storage and high temperature storage steps, the quality of the pineapple fruit is adjusted to a certain extent. When stored at room temperature, along with the increase of physiological indicators such as pineapple respiration and ethylene release, some flavor precursor substances of the pineapple fruit can be further converted into components with rich fruity aroma, making the flavor of the pineapple more rich and natural, and the pineapple flesh will naturally turn yellow at room temperature. Its color and texture will be more in line with consumers' cognition of mature pineapples, and its appearance and color can be better displayed, thereby enhancing consumers' eating experience and facilitating sales.

[0022] Furthermore, the method of the present invention can be used for pineapple fruits picked in summer and autumn, for example, pineapple fruits picked at 20-35°C (preferably 25-30°C) that are 70% or 80% ripe and without mechanical damage.

[0023] According to one embodiment, the method of the present invention may further include one or more of a sterilization step during harvesting, a pretreatment step of the harvested pineapple fruit, and a post-treatment step between a high temperature storage step and a room temperature storage step.

[0024] Specifically, the sterilization step may include using a 0.9-1.0 mL / L aqueous solution of prochloraz to sterilize the harvested pineapple. Preferably, the sterilization step may include soaking the fruit stalk of the harvested pineapple fruit with a 0.9-1.0 mL / L aqueous solution of prochloraz, or harvesting the pineapple with an instrument coated with the aqueous solution of prochloraz, such as dipping a blade for harvesting the pineapple into the aqueous solution of prochloraz when harvesting the pineapple.

[0025] This sterilization step can effectively kill the pathogens that have been infected on the surface of the fruit stalk and the pathogens lurking inside the fruit, preventing the further spread of the disease, thereby reducing the occurrence of diseases in pineapple fruits during storage, transportation and sales, and can extend the shelf life of pineapples, keeping the quality characteristics of pineapple fruits such as texture and sweetness stable.

[0026] The pretreatment step may include spraying the pretreatment composition onto the surface of the pineapple fruit to completely wet the surface of the pineapple fruit. The pretreatment step may further improve the ability of the pineapple fruit to resist blackheart disease.

[0027] Further, the pretreatment composition includes at least two of proline, aminobutyric acid and aspartic acid, preferably includes three of proline, aminobutyric acid and aspartic acid, for example, it can be composed of proline, aminobutyric acid and aspartic acid. Specifically, the pretreatment composition can include 3.5-4g / L proline, 80-100mg / L γ-aminobutyric acid and 5-8g / L aspartic acid, or can be composed of 3.5-4g / L proline, 80-100mg / L γ-aminobutyric acid and 5-8g / L aspartic acid.

[0028] The pretreatment composition may further include 0.008-0.012% Tween 80, based on the total mass of the pretreatment composition. Thus, the pretreatment composition may include 3.5-4 g / L proline, 80-100 mg / L γ-aminobutyric acid, 5-8 g / L aspartic acid and 0.008-0.012% Tween 80, or may consist of 3.5-4 g / L proline, 80-100 mg / L γ-aminobutyric acid, 5-8 g / L aspartic acid and 0.008-0.012% Tween 80.

[0029] The above-mentioned post-treatment step may include fumigating the pineapple fruit after high-temperature storage with a 400-500 ppb 1-methylcyclopropene (1-MCP) aqueous solution for 11-13 hours.

[0030] Specifically, the relative humidity of the low temperature storage step, the high temperature storage step and the normal temperature storage step may be 80-90% RH.

[0031] The pineapple treated by the method of the present invention can have a shelf life of 7 to 10 days even after being refrigerated, and the black heart index is 0 to 0.2.

[0032] Among them, the method for determining the relative area of ​​browning caused by black heart disease in pineapple is: remove the top bud of the pineapple, cut the pineapple longitudinally from the middle of the fruit axis, and the ratio of the browning area on the longitudinal section of the fruit to the entire longitudinal section area is the relative area of ​​browning.

[0033] Evaluation method of the severity of black heart disease: expressed by the browning degree of the pineapple heart, the browning degree of the pineapple heart is divided into 0 to 5 levels. Level 0: no browning; Level 1: the browning area is less than 10% of the total longitudinal cutting area; Level 2: the browning area accounts for 11% to 20% of the total longitudinal cutting area; Level 3: the browning area accounts for 21% to 30% of the total longitudinal cutting area; Level 4: the browning area accounts for 31% to 50% of the total longitudinal cutting area; Level 5: the browning area is greater than 50% of the total longitudinal cutting area.

[0034] The black heart index is the ratio of the sum of the products of each browning degree and the corresponding number of fruits of the browning degree to the total number of fruits, that is:

[0035] Wherein, i is an integer from 0 to 5, which is the browning degree; n i is the number of fruits with browning level i; N is the total number of fruits.

[0036] The method according to the present invention adopts a combination of multiple storage steps at different temperatures, which can resist the cold damage to pineapple fruits caused by low temperature refrigeration, prolong the storage time at room temperature after low temperature refrigeration, and make the black heart disease index of pineapple fruits stored for 7 days as low as 0-0.2, thereby achieving better preservation effect and black heart disease prevention and control effect through a simple variable temperature storage method.

[0037] In order to further understand the present invention, the technology provided by the present invention is described in detail below in conjunction with embodiments, and the protection scope of the present invention is not limited by the following embodiments.

[0038] Example 1

[0039] (1) Harvesting pineapple fruits

[0040] The pineapple variety used in this experiment was "Bali" pineapple (Ananas comosus'Comtede Paris'), which was picked at the Xuwen Pineapple Experimental Base in Zhanjiang City, Guangdong Province. When picking, the 70% mature fruits with uniform size and no mechanical damage were selected. The harvesting temperature was 25℃.

[0041] Among them, the knives used during harvesting were smeared with 0.9mL / L of myclobutanil aqueous solution.

[0042] (2) Storage and processing

[0043] The dried pineapple fruits were placed in layers in a constant temperature and humidity incubator, the temperature in the incubator was set at 10°C, the relative humidity was controlled at 80-90%, and the low temperature storage was 12 days; the temperature in the incubator was set at 38°C, and the high temperature storage was 3 days; the pineapple fruits were taken out of the incubator and stored at room temperature at 25°C and relative humidity of 80-90%. The occurrence of black heart disease was observed on the 3rd, 7th and 10th days of storage at room temperature. The storage time at room temperature was taken as the shelf life.

[0044] (3) Effect evaluation

[0045] After storage, the pineapple fruit was cut longitudinally from the middle of the fruit axis after removing the terminal buds. The relative area of ​​browning in the pineapple fruit core was measured, and then the black heart disease index and incidence rate were calculated. Each treatment was repeated 3 times with 15 fruits.

[0046] Method for determining the relative area of ​​browning due to black heart disease in pineapple: remove the top bud of the pineapple, cut the pineapple longitudinally from the middle of the fruit axis, and the ratio of the browning area on the longitudinal section of the fruit to the entire longitudinal section area is the relative area of ​​browning.

[0047] Evaluation method for the severity of black heart disease: The browning degree of the pineapple heart is divided into 0 to 5 levels. Level 0: no browning; Level 1: the browning area is less than 10% of the total longitudinal cutting area; Level 2: the browning area accounts for 11% to 20% of the total longitudinal cutting area; Level 3: the browning area accounts for 21% to 30% of the total longitudinal cutting area; Level 4: the browning area accounts for 31% to 50% of the total longitudinal cutting area; Level 5: the browning area is greater than 50% of the total longitudinal cutting area.

[0048] Wherein, i is an integer from 0 to 5, which is the browning degree; n i is the number of fruits with browning level i; N is the total number of fruits.

[0049] Calculation method for black heart disease incidence rate: Black heart disease incidence rate (%) = number of black heart disease-affected fruits / total number of fruits × 100.

[0050] Furthermore, the day before the first detection of black heart disease was recorded as the black heart disease onset day.

[0051] The black heart disease index of pineapple fruit was measured to be 0 after 3 days of storage, and the incidence of black heart disease was 0; the black heart disease index after 7 days of storage was 0.2, and the incidence of black heart disease was 9.8%; the black heart disease index after 10 days of storage was 1.2, and the incidence of black heart disease was 19.4%.

[0052] Example 2

[0053] Pineapple fruits were treated in the same manner as in Example 1, except that a pretreatment step was included between the harvesting and storage treatments.

[0054] The pretreatment of pineapple fruit was carried out as follows:

[0055] Prepare an aqueous solution according to the ratio of 3.5 g / L proline, 100 mg / L γ-aminobutyric acid, 5 g / L aspartic acid and 0.010% Tween 80. Spray the prepared aqueous solution on the surface of the pineapple fruit until the surface of the pineapple fruit is completely wet for pretreatment, and dry it for later use.

[0056] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 0, and the black heart disease incidence was 0; the black heart disease index after 7 days of storage was 0.1, and the black heart disease incidence was 3.6%; the black heart disease index after 10 days of storage was 0.8, and the black heart disease incidence was 8.3%.

[0057] Example 3

[0058] The pineapple fruits were treated in the same manner as in Example 1, except that a fumigation step was further included between the low temperature storage and the high temperature storage of the storage treatment, which was specifically performed as follows:

[0059] The dried pineapple fruits are placed in layers in a constant temperature and humidity incubator, the temperature in the incubator is set at 10° C., the relative humidity is controlled at 80-90%, and the low temperature is stored for 12 days;

[0060] Set the temperature in the box to 38°C and store at high temperature for 3 days;

[0061] The pineapple fruits were taken out of the incubator, placed in a sealed box containing a 400 ppb 1-MCP aqueous solution, and fumigated at 25°C for 12 hours;

[0062] The pineapple fruits were taken out of the sealed box and stored at room temperature of 25°C and relative humidity of 80-90%.

[0063] The occurrence of blackheart disease was observed on the 3rd, 7th and 10th days of storage at room temperature.

[0064] The black heart disease index of pineapple fruit was measured to be 0 after 3 days of storage, and the incidence of black heart disease was 0; the black heart disease index after 7 days of storage was 0.1, and the incidence of black heart disease was 5.7%; the black heart disease index after 10 days of storage was 1.0, and the incidence of black heart disease was 10.1%.

[0065] Example 4

[0066] The pineapple fruit was treated in the same manner as in Example 1, except that the pretreatment step and fumigation step of Examples 2 and 3 were performed.

[0067] It was measured that the black heart disease index of pineapple fruit after 3 days of storage was 0, and the black heart disease incidence rate was 0; the black heart disease index after 7 days of storage was 0, and the black heart disease incidence rate was 0; the black heart disease index after 10 days of storage was 0.1, and the black heart disease incidence rate was 0.9%.

[0068] Example 5

[0069] The pineapple fruits were treated in the same manner as in Example 1, except that the low temperature storage was 5° C. for 10 days and the high temperature storage was 35° C. for 5 days.

[0070] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 0, and the black heart disease incidence rate was 0; the black heart disease index after 7 days of storage was 0.2, and the black heart disease incidence rate was 8.1; the black heart disease index after 10 days of storage was 0.8, and the black heart disease incidence rate was 9.8%.

[0071] Example 6

[0072] The pineapple fruit was treated in the same manner as in Example 5, except that the pretreatment step of Example 2 was performed.

[0073] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 0, and the black heart disease incidence rate was 0; the black heart disease index after 7 days of storage was 0.1, and the black heart disease incidence rate was 2.5; the black heart disease index after 10 days of storage was 0.2, and the black heart disease incidence rate was 5.9%.

[0074] Example 7

[0075] The pineapple fruits were treated in the same manner as in Example 5, except that the fumigation step of Example 3 was performed.

[0076] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 0, and the black heart disease incidence rate was 0; the black heart disease index after 7 days of storage was 0.1, and the black heart disease incidence rate was 5.3; the black heart disease index after 10 days of storage was 0.5, and the black heart disease incidence rate was 8.7%.

[0077] Example 8

[0078] The pineapple fruit was treated in the same manner as in Example 5, except that the pretreatment step and fumigation step of Examples 2 and 3 were performed.

[0079] It was measured that the black heart disease index of pineapple fruit was 0 after 3 days of storage, and the black heart disease incidence rate was 0; the black heart disease index was 0 after 7 days of storage, and the black heart disease incidence rate was 0; the black heart disease index was 0 after 10 days of storage, and the black heart disease incidence rate was 0.

[0080] Comparative Example 1

[0081] Pineapple fruits were treated in the same manner as in Example 5, except that the high temperature storage step was not performed.

[0082] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 1.2, and the black heart disease incidence rate was 61.4; the black heart disease index after 7 days of storage was 3.2, and the black heart disease incidence rate was 85.8; the black heart disease index after 10 days of storage was 5.0, and the black heart disease incidence rate was 100.

[0083] Comparative Example 2

[0084] Pineapple fruits were treated in the same manner as in Example 1, except that the high temperature storage step was performed at 30°C for 5 days.

[0085] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 0.7, and the black heart disease incidence rate was 54.6; the black heart disease index after 7 days of storage was 1.8, and the black heart disease incidence rate was 76.1; the black heart disease index after 10 days of storage was 4.2, and the black heart disease incidence rate was 100.

[0086] Comparative Example 3

[0087] Pineapple fruits were treated in the same manner as in Example 1, except that the high temperature storage step was not performed.

[0088] The black heart disease index of pineapple fruit after 3 days of storage was measured to be 2.2, and the black heart disease incidence rate was 83.3; the black heart disease index after 7 days of storage was 4.8, and the black heart disease incidence rate was 94.5; the black heart disease index after 10 days of storage was 5.0, and the black heart disease incidence rate was 100.

[0089] The control effect data of the above embodiments and comparative examples are shown in Table 1.

[0090] Table 1 Control effect of different treatments on blackheart disease in postharvest pineapples

[0091]

[0092] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preventing and treating postharvest blackheart disease of pineapples, characterized in that: The following steps are involved: Store the harvested pineapple fruits at a temperature of 4 to 10°C for 10 to 14 days; The pineapple fruits after low temperature storage are stored at a high temperature of 35-38°C for 3-5 days; Store the pineapple fruits at room temperature after high-temperature storage.

2. The method according to claim 1 further comprises pre-treating the harvested pineapple fruits; The pretreatment comprises spraying the pretreatment composition onto the surface of the pineapple fruit, so that the surface of the pineapple fruit is completely wet; in, The pretreatment composition includes at least two of proline, aminobutyric acid, and aspartic acid.

3. The method according to claim 2, wherein the pretreatment composition comprises 3.5-4 g / L proline, 80-100 mg / L γ-aminobutyric acid, and 5-8 g / L aspartic acid.

4. The method according to claim 3, wherein the pretreatment composition further comprises 0.008-0.012% Tween 80.

5. The method according to any one of claims 1 to 4, further comprising performing a post-treatment between the high-temperature storage and the room-temperature storage, wherein the post-treatment comprises fumigating the pineapple fruit after the high-temperature storage with a 400-500 ppb 1-methylcyclopropene aqueous solution for 11-13 hours.

6. The method according to claim 1 further comprises sterilizing the pineapples with a 0.9-1.0 mL / L aqueous solution of prochloraz.

7. The method according to claim 6, wherein the sterilization step comprises soaking the stalks of the harvested pineapple fruits with a 0.9-1.0 mL / L aqueous solution of prochloraz, or smearing the utensil for harvesting pineapples with the aqueous solution of prochloraz.

8. The method according to claim 1, wherein the pineapple is harvested at a temperature of 20 to 35°C.

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