A method to promote the ripening and softening of postharvest kiwifruit

Abstract

This invention belongs to the technical field of food processing, specifically relating to a method for promoting the ripening and softening of post-harvest kiwifruit. This invention promotes the ripening and softening of kiwifruit by subjecting it to heat dissipation, disinfection, and temperature-controlled treatment, resulting in kiwifruit that is ready to eat. Simultaneously, by combining the ripening regulator specifically prepared according to this invention, the efficiency of kiwifruit ripening and softening can be artificially controlled, and the stability of the ripening effect is greatly improved. Experiments show that using the technical solution provided by this invention, post-harvest kiwifruit can be eaten in as little as 3 days, with a shelf life extended by 10-12 days. Furthermore, the ripened kiwifruit exhibits more complete starch degradation, higher soluble sugar content, and better fruit quality.

Description

Technical Field

[0001] This invention belongs to the technical field of food processing, specifically relating to a method for promoting the ripening and softening of postharvest kiwifruit. Background Technology

[0002] Kiwifruit (Actinidia chinensis) is an important economic fruit crop in my country and one of the world's mainstream consumer fruits. It is not only highly nutritious but also has effects such as lowering blood pressure and preventing cancer, thus earning it the title of "King of Fruits." However, kiwifruit is a deciduous fruit; it cannot be eaten immediately after harvesting and needs to ripen and soften over a period of time to develop its unique flavor before consumption.

[0003] In existing technologies, ethylene is often used to promote the ripening and softening of kiwifruit, but its ripening effect is unstable. In other words, while ethylene treatment can effectively accelerate the softening process of kiwifruit, it also causes problems such as excessively rapid softening, incomplete starch conversion, and significant loss of vitamin C, affecting fruit quality and causing substantial losses. Therefore, how to stabilize the ripening effect of kiwifruit and ensure fruit quality is an urgent problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for promoting the ripening and softening of kiwifruit after harvest, which is beneficial for kiwifruit to be eaten immediately and has a stable effect and good fruit quality.

[0005] This invention provides a method for promoting the ripening and softening of postharvest kiwifruit, comprising the following steps:

[0006] The harvested kiwifruit were then cooled and disinfected to obtain disinfected kiwifruit.

[0007] The disinfected and sterilized kiwifruit is subjected to a temperature change treatment to obtain temperature-changed kiwifruit.

[0008] The kiwifruit that had changed temperature was soaked in a ripening agent to accelerate ripening.

[0009] The ripening regulator uses water as a solvent and also includes the following components at concentrations: 600–800 mg / L of ABA, 11–14 mg / L of melatonin, 0.5 wt.%–1 wt.% of trehalose, and 0.1%–0.15% of Tween 20 by volume.

[0010] Preferably, the kiwifruit varieties include one or more of Jinyan, Jinkui, Jinguo, Hongshier, Hongyang, and Xuxiang.

[0011] Preferably, when the kiwifruit is harvested, the soluble solids content is 6.5%–7.5%, and the firmness is 15–18 kg / cm². 2 .

[0012] Preferably, the temperature-changing treatment includes low-temperature storage and room-temperature standing of the disinfected kiwifruit.

[0013] The conditions for low-temperature storage include: a temperature of 1 to 2°C, a humidity of 90% to 95%, and a storage time of ≥3 days.

[0014] The conditions for standing at room temperature include: a temperature of 16–22°C and a time of 4–8 hours.

[0015] Preferably, the heat dissipation time is 8 to 12 hours.

[0016] Preferably, the disinfection and sterilization includes: soaking the kiwifruit after it has cooled down using a disinfectant;

[0017] The disinfectant includes a chlorine dioxide solution with a concentration of 35–45 mg / L.

[0018] Preferably, the soaking time is 10 to 15 minutes.

[0019] Preferably, the soaking time during the ripening process is 5 to 10 minutes.

[0020] Preferably, the method further includes: individually packaging and storing the ripened kiwifruit;

[0021] The storage temperature is 16–22°C.

[0022] Preferably, the material for the single-fruit packaging is a food preservation bag.

[0023] Beneficial effects:

[0024] This invention provides a method for promoting the ripening and softening of postharvest kiwifruit, comprising the following steps: sequentially subjecting postharvest kiwifruit to heat dissipation and sterilization to obtain sterilized kiwifruit; subjecting the sterilized kiwifruit to temperature-changing treatment to obtain temperature-changed kiwifruit; and soaking the temperature-changed kiwifruit in a ripening regulator to promote ripening. The ripening regulator uses water as a solvent and further comprises the following components at concentrations: 600–800 mg / L of ABA, 11–14 mg / L of melatonin, 0.5 wt.%–1 wt.% of trehalose, and 0.1%–0.15% of Tween 20 (by volume). This invention, by subjecting postharvest kiwifruit to heat dissipation, sterilization, and temperature-changing treatment, not only improves the quality of kiwifruit but also promotes ripening and softening. Furthermore, combined with the specifically prepared ripening regulator of this invention, it facilitates the artificial control of the ripening and softening efficiency of kiwifruit, achieving a ready-to-eat effect and significantly improving the stability of the ripening effect. Experiments show that, using the technical solution provided by this invention, kiwifruit can be eaten as early as 3 days after harvest, extending the shelf life by 10-12 days. Furthermore, the ripened kiwifruit exhibits more complete starch degradation, higher soluble sugar content, and better fruit quality. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0026] Figure 1 To analyze the ripening effect of kiwifruit in Example 1 and Comparative Example 1;

[0027] Figure 2 To analyze the ripening effect of kiwifruit in Example 2 and Comparative Example 2;

[0028] Figure 3 To analyze the starch and polysaccharide content of the fruits treated for 12 days in Example 1 and Comparative Example 1. Detailed Implementation

[0029] This invention provides a method for promoting the ripening and softening of postharvest kiwifruit, comprising the following steps: sequentially subjecting postharvest kiwifruit to heat dissipation and sterilization to obtain sterilized kiwifruit; subjecting the sterilized kiwifruit to temperature change treatment to obtain temperature-changed kiwifruit; and soaking the temperature-changed kiwifruit in a ripening regulator to promote ripening; wherein the ripening regulator uses water as a solvent and further comprises the following components at concentrations: 600–800 mg / L of ABA, 11–14 mg / L of melatonin, 0.5 wt.%–1 wt.% of trehalose, and Tween 20 at a volume ratio concentration of 0.1%–0.15%.

[0030] Unless otherwise specified, all reagents and raw materials used in this invention are conventionally purchased.

[0031] This invention preferably involves harvesting kiwifruit. The kiwifruit varieties used in this invention are preferably one or more of the following: Jin Yan, Jin Kui, Jinguo, Hong Shi Er, Hong Yang, and Xu Xiang. When harvesting the kiwifruit, this invention preferably selects varieties based on the fruit's condition. The preferred fruit condition is the content of soluble solids and the firmness; that is, the kiwifruit is harvested when both the content of soluble solids and the firmness meet the corresponding standards. During harvesting, the preferred soluble solids content is 6.5%–7.5%; the preferred firmness is 15–18 kg / cm². 2 The present invention does not have special requirements for the method of determining the state of the kiwifruit; any technique well known in the art can be used. In a specific embodiment of the present invention, the instrument for measuring soluble solids is an ATAGO digital refractometer; the instrument for measuring fruit firmness is a GY-4 fruit firmness tester from Zhejiang Top Cloud-Agri Technology Co., Ltd.

[0032] After harvesting, the present invention preferably performs preliminary screening on the harvested kiwifruit. In the present invention, the preliminary screening is preferably to remove bad and / or rotten fruit from the harvested kiwifruit, thereby ensuring the synchronous ripening and softening of the kiwifruit; there are no special requirements for the method of preliminary screening, and techniques well known in the art can be used.

[0033] After the initial screening, the present invention cools the pre-screened kiwifruit. In this invention, the cooling time is preferably 8-12 hours, more preferably 10 hours; the cooling is preferably performed using forced air; the cooling is preferably carried out in a cool, shaded area; after cooling, the fruit temperature of the kiwifruit is preferably 18-19°C. Using the above method, the kiwifruit fruit can be sufficiently cooled.

[0034] After cooling, the present invention disinfects and sterilizes the kiwifruit. The disinfection and sterilization process preferably involves soaking, drying, and packaging the cooled kiwifruit in sequence using a disinfectant. The disinfectant preferably includes a chlorine dioxide solution; the concentration of the chlorine dioxide solution is preferably 35–45 mg / L, more preferably 40 mg / L; the soaking time is preferably 10–15 minutes, more preferably 13 minutes; there are no special requirements for the amount of disinfectant used during soaking, as long as the kiwifruit is completely submerged; there are no special requirements for the drying method and time, as long as the fruit surface is free of moisture; the packaging is preferably individual fruit packaging; the packaging material is preferably a food storage bag; the source of the food storage bag is not special, and it can be purchased conventionally.

[0035] After disinfection and sterilization, the present invention stores the disinfected and sterilized kiwifruit at low temperature. The preferred temperature for low-temperature storage is 1–2°C, more preferably 1°C; the preferred humidity for low-temperature storage is 90%–95%, more preferably 93%; and the preferred storage time is ≥3 days.

[0036] After low-temperature storage, the present invention subjectes the kiwifruit to room temperature stabilization. The kiwifruit subjected to room temperature stabilization is preferably kiwifruit with the preservation bag removed; the room temperature stabilization temperature is preferably 16–22°C, more preferably 19°C; the room temperature stabilization time is preferably 4–8 hours, more preferably 8 hours, to facilitate the warming up of the kiwifruit after low-temperature storage.

[0037] After being left to stand at room temperature, the present invention preferably performs a secondary screening on the kiwifruit. The secondary screening is preferably based on the firmness of the kiwifruit; the firmness of the kiwifruit is preferably 15–18 kg / cm². 2 More preferably 16-17 kg / cm² 2 This improves the initial uniformity of kiwifruit.

[0038] After the secondary screening, the present invention soaks and ripens the kiwifruit after the secondary screening. In the present invention, the soaking and ripening is preferably carried out by soaking and drying the kiwifruit after it has been left to stand at room temperature using a ripening regulator. In the present invention, the ripening regulator uses water as a solvent and further includes the following components at concentrations: 600–800 mg / L of ABA, 11–14 mg / L of melatonin, 0.5 wt.%–1 wt.% of trehalose, and 0.1%–0.15% of Tween 20 by volume. The concentration of abscisic acid (ABA) in the ripening regulator of this invention is preferably 700-800 mg / L, more preferably 800 mg / L; adding abscisic acid helps accelerate plant ripening. The concentration of melatonin in the ripening regulator is preferably 13-14 mg / L, more preferably 14 mg / L; adding melatonin helps control post-harvest infection in kiwifruit, alleviate chilling injury, and delay senescence. The concentration of trehalose in the ripening regulator is preferably 0.7 wt.%-0.8 wt.%, more preferably 0.8 wt.%; adding trehalose not only helps reduce the loss of nutrients in the fruit but also prevents oxygen from interacting with enzymes in the fruit. The volume ratio concentration of Tween 20 in the ripening regulator is preferably 0.1%-0.12%, more preferably 0.1%. There are no special requirements for the preparation method of the ripening regulator of this invention; uniform mixing is sufficient. The ripening regulator prepared by the above technical solution is beneficial for artificially controlling the ripening and softening speed of kiwifruit.

[0039] The soaking method described in this invention is preferably light-protected soaking; the soaking time is preferably 5 to 10 minutes, more preferably 10 minutes; there are no special requirements for the amount of ripening regulator used, as long as the kiwifruit is completely submerged; there are no special requirements for the drying method, as long as there is no moisture on the surface of the kiwifruit.

[0040] After soaking and ripening, the present invention preferably packages and stores the ripened kiwifruit individually. In this invention, the packaging material is preferably a food storage bag; the packaging method has no special requirements and can be any technique well-known in the art; storage is preferably in a cool, dark place; the storage temperature is preferably 16–22°C, more preferably 19°C, which is beneficial for promoting the ripening of the kiwifruit.

[0041] Using the technical solution provided by this invention, kiwifruit can be eaten as early as 3 days after harvest, extending the shelf life by 10-12 days. Furthermore, the ripened kiwifruit undergoes more complete starch degradation, has a higher soluble sugar content, and exhibits better fruit quality.

[0042] To further illustrate the present invention, the following detailed description of a method for promoting the ripening and softening of postharvest kiwifruit, in conjunction with the accompanying drawings and embodiments, is provided by the present invention, but should not be construed as limiting the scope of protection of the present invention.

[0043] The kiwifruit used in Examples 1-2 and Comparative Examples 1-13 were all harvested from the same batch and subjected to different treatments.

[0044] Example 1

[0045] A method for promoting the ripening and softening of postharvest kiwifruit, comprising the following steps:

[0046] Experimental site: Doctor Kiwi Fruit Base, Fengxin County, Yichun City, Jiangxi Province; kiwi fruit variety: Jinyan kiwi fruit.

[0047] 1) Harvesting: On October 10, 2022, kiwifruit were evenly collected from different trees in the orchard, with samples collected from all four directions (north, south, east, and west) on each tree. Ten kiwifruit were selected from each direction, and the fruit firmness and soluble solids content were measured. The soluble solids content of the fruit was 6.5%–7.5%, and the firmness was 15–18 kg / cm². 2 When the time is right, begin harvesting the fruit. Wear gloves while harvesting, handle the fruit gently, and avoid colliding with the fruit during transportation.

[0048] 2) Heat dissipation and disinfection: Perform preliminary screening on the kiwifruit picked in step 1) to remove bad and rotten fruit;

[0049] After initial screening, the fruits were left in a cool place overnight (10 hours) with ventilation to allow the fruits picked from the field to cool down fully.

[0050] The fruits were soaked in a chlorine dioxide solution with a concentration of 40 mg / L for 10 minutes, then removed and thoroughly dried to complete the sterilization of the fruit surface before storage. The sterilized fruits were then packaged in plastic bags and divided into 100 fruits per basket.

[0051] 3) Temperature change treatment: Move the packaged fruits from step 2) into a cold storage. The temperature of the cold storage is 1-2℃ and the humidity is 93-95%. After two weeks, take out 4 baskets of fruits, remove the plastic bags from the kiwifruit, and place the kiwifruit at room temperature for 6 hours to allow it to warm up.

[0052] After rewarming, the fruit firmness was measured again, and fruits with a firmness of 15-18 kg / cm were selected. 2 There are 300 fruits, divided into 3 groups of 100 each.

[0053] 4) Soaking and ripening: Prepare a ripening regulator, wherein the ripening regulator uses water as a solvent and is composed of the following components at the following concentrations: 700 mg / L abscisic acid, 12 mg / L melatonin, 1 wt.% trehalose and 0.1% Tween 20 by volume. The above substances are thoroughly mixed to obtain the product.

[0054] Immerse the fruit from step 3) completely in the ripening agent for 10 minutes, remove the fruit and air dry in a cool place. Pack each fruit individually in a fruit preservation bag and place in a preservation box at room temperature of 20±2℃ to ripen.

[0055] Example 2

[0056] The difference from Example 1 is that the kiwi fruit variety is Jin Kui kiwi fruit.

[0057] Example 3

[0058] The difference from Example 1 is that the kiwi fruit variety is Golden Kiwi.

[0059] Example 4

[0060] The difference from Example 1 is that the kiwi fruit variety is Xu Xiang kiwi fruit.

[0061] Example 5

[0062] The difference from Example 1 is that the kiwi fruit variety is Red Twelve kiwi fruit.

[0063] Example 6

[0064] The difference from Example 1 is that the kiwi fruit variety is Hongyang kiwi fruit.

[0065] Comparative Example 1

[0066] The difference from Example 1 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0067] Comparative Example 2

[0068] The difference from Example 2 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0069] Comparative Example 3

[0070] The difference from Example 3 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0071] Comparative Example 4

[0072] The difference from Example 4 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0073] Comparative Example 5

[0074] The difference from Example 5 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0075] Comparative Example 6

[0076] The difference from Example 6 is that in step 4), the kiwifruit is soaked in water to ripen it.

[0077] Comparative Example 7

[0078] The difference from Example 1 is that the ripening regulator in step 4) uses water as a solvent and consists of the following components at the following concentrations: 350 mg / L abscisic acid, 6 mg / L melatonin, 0.5 wt.% trehalose and 0.1% Tween 20 by volume.

[0079] Comparative Example 8

[0080] The difference from Example 1 is that the ripening regulator in step 4) uses water as a solvent and consists of the following components at the following concentrations: 175 mg / L abscisic acid, 3 mg / L melatonin, 0.25 wt.% trehalose and 0.1% Tween 20 by volume.

[0081] Comparative Example 9

[0082] The difference from Example 1 is that the ripening regulator in step 4) uses water as a solvent and consists of the following components at the following concentrations: 87.5 mg / L abscisic acid, 1.5 mg / L melatonin, 0.125 wt.% trehalose and 0.1% Tween 20 by volume.

[0083] Comparative Example 10

[0084] The difference from Example 1 is that the ripening regulator in step 4) uses water as a solvent and consists of the following components at the following concentrations: 20 mg / L gibberellin, 12 mg / L melatonin, 1 wt.% trehalose and 0.1% Tween 20 by volume.

[0085] Comparative Example 11

[0086] The difference from Example 1 is that the ripening regulator in step 4) uses water as a solvent and consists of the following components at the following concentrations: 40 mg / L gibberellin, 12 mg / L melatonin, 1 wt.% trehalose and 0.1% Tween 20 by volume.

[0087] Comparative Example 12

[0088] The difference from Example 1 is that in step 4), the ripening regulator is water-based and consists of the following components at the following concentrations: 80 mg / L gibberellin, 12 mg / L melatonin, 1 wt.% trehalose, and 0.1% Tween 20 by volume.

[0089] Comparative Example 13

[0090] The difference from Example 1 is that in step 4), the ripening regulator uses water as a solvent and consists of the following components at the following concentrations: 160 mg / L gibberellin, 12 mg / L melatonin, 1 wt.% trehalose and 0.1% Tween 20 by volume.

[0091] Comparative Example 14

[0092] The difference from Example 1 is that in step 4), the ripening regulator uses water as a solvent and consists of the following components at the following concentrations: 25 mg / L of auxin NAA, 12 mg / L of melatonin, 1 wt.% of trehalose and 0.1% of Tween 20 by volume.

[0093] Comparative Example 15

[0094] The difference from Example 1 is that in step 4), the ripening regulator uses water as a solvent and consists of the following components at the following concentrations: 50 mg / L of auxin NAA, 12 mg / L of melatonin, 1 wt.% of trehalose and 0.1% of Tween 20 by volume.

[0095] Comparative Example 16

[0096] The difference from Example 1 is that in step 4), the ripening regulator uses water as a solvent and consists of the following components at the following concentrations: 100 mg / L of auxin NAA, 12 mg / L of melatonin, 1 wt.% of trehalose and 0.1% of Tween 20 by volume.

[0097] Comparative Example 17

[0098] The difference from Example 1 is that in step 4), the ripening regulator uses water as a solvent and consists of the following components at the following concentrations: 200 mg / L of auxin NAA, 12 mg / L of melatonin, 1 wt.% of trehalose and 0.1% of Tween 20 by volume.

[0099] Comparative Example 18

[0100] The difference from Example 1 is that the fruit was not stored in a cold storage at low temperature in step 3), but the fruit that was fully dried in step 2) was directly soaked in the ripening regulator.

[0101] Results and Analysis:

[0102] The edible time, shelf life, and firmness of kiwifruit in Examples 1-2 and Comparative Examples 1-13 were compared. 2 At that time, the soluble solids content and solid-acid ratio of kiwifruit during the edible period were statistically analyzed, and the results are shown in Table 1. Figure 1 and Figure 2 Paraffin section analysis was performed on the starch and polysaccharide contents of fruits treated for 12 days in Example 1 and Comparative Example 1. The results are shown in [Figure 1]. Figure 3 .

[0103] Table 1 Effects of different treatments on different traits of kiwifruit

[0104]

[0105]

[0106] As shown in Table 1, using the technical solution provided by this invention, kiwifruit can be eaten as early as 3 days after harvest, extending the shelf life by 10-12 days. The sugar-acid ratio of Example 1 and Comparative Example 1 shows that the flavor of kiwifruit of the same variety varies significantly after ripening with different treatments. However, using the technical solution provided by this invention, the sugar-acid ratio of the kiwifruit increased from 55.16 to 70.57, resulting in excellent flavor. The treatment results of Example 1 and Comparative Example 14 show that the edible period of fruit without temperature change treatment is delayed by 7 days, similar to that of Comparative Example 1 with water, indicating that the ripening agent effect is not significant.

[0107] In addition, combined Figures 1-3 As can be seen from the observation of starch state and content by potassium iodide staining and transmission electron microscopy, the number and size of starch granules in Example 1 (black and white, respectively) were smaller than those in Comparative Example 1. PAS staining also revealed that the polysaccharide granules (purple-red) in Example 1 were significantly fewer than those in Comparative Example 1. Therefore, it can be concluded that treatment of kiwifruit with the ripening regulator provided by this invention can significantly promote the conversion of starch and polysaccharides.

[0108] In summary, the technical solution provided by this invention not only promotes the ripening and softening of kiwifruit but also significantly improves the stability of the ripening effect. Kiwifruit can be consumed as early as 3 days after harvest, extending the shelf life by 10-12 days. Furthermore, the ripened kiwifruit exhibits more complete starch degradation, higher soluble sugar content, and superior fruit quality. Therefore, the technical solution of this invention is suitable for commercially stored kiwifruit in cold storage, is simple to operate, and possesses extremely high application value and economic benefits.

[0109] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for promoting the ripening and softening of postharvest kiwifruit, characterized in that, Includes the following steps: The harvested kiwifruit were then cooled and disinfected to obtain disinfected kiwifruit. The disinfected and sterilized kiwifruit is subjected to a temperature change treatment to obtain temperature-changed kiwifruit. The variable temperature treatment includes low-temperature storage and room-temperature standing of the disinfected and sterilized kiwifruit. The conditions for low-temperature storage include: temperature of 1~2℃, humidity of 90%~95%, and time of ≥3 days; The conditions for standing at room temperature include: temperature of 16~22℃ and time of 4~8h; The kiwifruit that had changed temperature was soaked in a ripening agent to accelerate ripening. The ripening regulator uses water as a solvent and also includes the following components at concentrations: 600-800 mg / L of ABA, 11-14 mg / L of melatonin, 0.5 wt.%-1 wt.% of trehalose, and Tween 20 at a volume ratio of 0.1-0.15%. The kiwifruit varieties mentioned include one or more of Jinyan, Jinguo, Hongshi No. 2, Hongyang, and Xuxiang.

2. The method according to claim 1, characterized in that, When the kiwifruit is harvested, the soluble solids content is 6.5%~7.5%, and the firmness is 15~18 kg / cm². 2 .

3. The method according to claim 1, characterized in that, The heat dissipation time is 8~12 hours.

4. The method according to claim 1, characterized in that, The disinfection and sterilization process includes: soaking the cooled kiwifruit in a disinfectant; The disinfectant includes a chlorine dioxide solution with a concentration of 35-45 mg / L.

5. The method according to claim 4, characterized in that, The soaking time is 10-15 minutes.

6. The method according to claim 1, characterized in that, During the soaking and ripening process, the soaking time is 5-10 minutes.

7. The method according to claim 1, characterized in that, The method also includes: individually packaging and storing ripened kiwifruit; The storage temperature is 16~22℃.

8. The method according to claim 7, characterized in that, The material used for packaging individual fruits is a food preservation bag.

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