A method for storing fresh vegetables

Abstract

The present application belongs to the technical field of vegetable storage and preservation, and particularly relates to a fresh vegetable storage and preservation method. The fresh vegetable is coated with pepper leaf essential oil and then packaged; the packaged vegetable is stored in a low-pressure electrostatic field and a low-temperature environment. The present application uses the pepper leaf essential oil coating, combined with the low-temperature and low-pressure electrostatic field preservation technologies, which have a synergistic effect, can obviously inhibit the pectin and cellulose degradation enzyme activity, reduce the metabolic decomposition of the cell wall structure components such as pectin and cellulose, reduce the loss of the nutritional components and water of the vegetable, maintain the texture characteristics of the vegetable, delay the oxidative decomposition of the chlorophyll components, thereby maintaining the original color quality of the vegetable, delaying the yellowing of the vegetable, inhibiting the postharvest physiological metabolism of the vegetable, delaying the consumption of the soluble solids of the vegetable, inhibiting the membrane lipid peroxidation, reducing the accumulation of malondialdehyde, and prolonging the shelf life of the fresh vegetable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vegetable storage and preservation, and particularly relates to a fresh vegetable storage and preservation method. BACKGROUND

[0002] Fresh vegetables (peppers, cabbage, etc.) are rich in vitamins and various mineral elements such as calcium, magnesium, potassium, phosphorus and iron, and have various physiological health activities, so they have become a very popular food material. However, due to the high water content of fresh vegetables, various physiological metabolic activities in postharvest fruits are still active, so they are prone to water loss, wilting, aging, yellowing and rotting. If the storage temperature is not properly controlled, cold damage is likely to occur, which seriously affects the appearance quality, nutritional quality of the vegetables and shortens their shelf life. Statistics show that the loss rate of peppers / cabbage from picking to processing is as high as 30%, which seriously damages the interests of producers and operators.

[0003] The postharvest storage and preservation methods of fresh vegetables reported so far include physical methods (such as cold storage, controlled atmosphere, heat treatment, ultrasonic waves, etc.) and chemical methods (such as chemical fungicides, plant regulators, etc.). Cold storage, i.e. low-temperature preservation, is the most common postharvest preservation method for peppers and cabbage. However, long-term production practice has found that simple cold storage treatment is difficult to achieve ideal preservation effect. Controlled atmosphere preservation equipment is high in cost and requires "whole storage and whole retrieval", which is poor in flexibility, thus limiting its application in the industry. Heat treatment and ultrasonic waves have the disadvantage of high energy consumption. When using chemical methods for storage and preservation, a large amount of chemical preservatives is usually required. However, a large number of studies have shown that the use of chemical preservatives has safety and residue problems, and has certain harmfulness to the environment and ecological balance. Therefore, it is urgent to develop an economic, efficient, safe and green method or technology for the preservation of fresh vegetables, especially fresh peppers and fresh cabbage, to reduce postharvest loss of vegetables and promote sustainable and healthy development of the industry. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, provide a fresh vegetable storage and preservation method, improve the preservation effect of fresh vegetables, especially fresh peppers and fresh cabbage, better maintain the color, texture, nutrition and other qualities of fresh vegetables, reduce the quality loss, and improve the commodity value of peppers and cabbage.

[0005] The present application provides a fresh vegetable storage and preservation method, which comprises the following steps:

[0006] The fresh vegetables are covered with pepper leaf essential oil and then stored in a low-voltage electrostatic field and a low-temperature environment.

[0007] The fresh vegetables include fresh peppers and / or fresh cabbage.

[0008] Preferably, the pepper leaf essential oil is the product of the pepper leaf after CO2 supercritical extraction.

[0009] Preferably, the amount of the pepper leaf essential oil is 15-17 mg / cm 2 .

[0010] Preferably, the field strength of the low-voltage electrostatic field is 0.3-2.5 kV / m.

[0011] Preferably, the temperature of the low-temperature environment is 2-12 ℃.

[0012] Preferably, before being placed in the low-voltage electrostatic field and the low-temperature environment for storage, the method further comprises: packaging the fresh vegetables coated with the pepper leaf essential oil.

[0013] The packaging process comprises: using a polyethylene film with holes to package the fresh vegetables coated with the pepper leaf essential oil.

[0014] Preferably, the polyethylene film with holes has a length of 30-50 cm, a width of 20-40 cm, and a thickness of 0.03-0.07 mm.

[0015] Preferably, the polyethylene film with holes has 1-3 holes, and each hole has a diameter of 4-8 mm.

[0016] Preferably, the packaging comprises heat sealing.

[0017] The heat sealing has a temperature of 120-180 ℃, a time of 3-5 s, and a pressure of 90-110 kPa.

[0018] Preferably, the fresh vegetables are vegetables harvested 0-2 h ago.

[0019] Beneficial effects:

[0020] The present application takes fresh peppers and fresh cabbages as examples, and covers the surface of fresh peppers and fresh cabbages with pepper leaf essential oil respectively, and then stores them in a low-pressure electrostatic field and a low-temperature environment. The pepper leaf essential oil can play a barrier role to prevent water loss. The pepper leaf essential oil also has good antioxidant capacity, can remove reactive oxygen species (ROS) free radicals in cells, or improve the content of antioxidants by regulating antioxidant system related enzyme activity and gene expression, and finally achieves the color protection effect. The low-pressure electrostatic field can promote the imbalance of the electric biological effect in the vegetables and the reduction of enzyme activity, inhibit the metabolism of the vegetables, and change the electric field distribution on the surface of the vegetables to form a weak adsorption force to adsorb the surrounding water molecules, reduce the water evaporation on the surface of the vegetables, and maintain a high water content in the vegetables and reduce the mass loss. The present application uses pepper leaf essential oil covering, combined with low-temperature and low-pressure electrostatic field preservation technology, and the three synergistically inhibit the pectin and cellulose degradation enzyme activity, reduce the metabolic decomposition of pectin, cellulose and other cell wall structural components, reduce the loss of nutrients and water in the vegetables, maintain the texture characteristics of the vegetables, delay the oxidation and decomposition of chlorophyll components, maintain the original color quality of the vegetables, delay the yellowing of the vegetables, inhibit the postharvest physiological metabolism of the vegetables, delay the consumption of soluble solids, inhibit membrane lipid peroxidation, reduce the accumulation of malondialdehyde, and prolong the shelf life of fresh vegetables. DETAILED DESCRIPTION

[0021] The present application provides a fresh vegetable storage and preservation method, comprising the following steps:

[0022] covering the surface of fresh vegetables with pepper leaf essential oil, and then storing them in a low-pressure electrostatic field and a low-temperature environment;

[0023] The fresh vegetables include fresh peppers and / or fresh cabbages.

[0024] In the present application, the surface of fresh vegetables is covered with pepper leaf essential oil. In the present application, the postharvest vegetables preferably include vegetables harvested for 0-2 hours, and further preferably include vegetables harvested for 0-1 hour.

[0025] In the present application, the amount of pepper leaf essential oil is preferably 15-17 mg / cm 2 , and further preferably 16 mg / cm 2The pepper leaf essential oil is preferably a product of CO2 supercritical extraction of pepper leaves. The number of times of CO2 supercritical extraction in the application is preferably 1-2, and is further preferably 1. The extraction pressure is preferably 25.0-26.0 MPa, and is further preferably 25.5 MPa. The extraction time is preferably 6 h. The extraction temperature is preferably 48-52 ℃, and is further preferably 50 ℃. The separation pressure of CO2 supercritical extraction is preferably 16.0-17.0 MPa, and is further preferably 16.5 MPa. The separation temperature is preferably 43-47 ℃, and is further preferably 45 ℃. The application can play a barrier role in covering the fresh vegetables with pepper leaf essential oil, preventing the loss of water. The pepper leaf essential oil also has good antioxidant capacity, can remove reactive oxygen species (ROS) free radicals in cells, or improve the content of antioxidants by regulating the activity and gene expression of antioxidant system related enzymes, and finally achieve the color protection effect.

[0026] After the application of pepper leaf essential oil, the fresh vegetables covered with pepper leaf essential oil are preferably subjected to packaging treatment. In the application, the packaging treatment preferably comprises: using a polyethylene film with holes to package the fresh vegetables after applying pepper leaf essential oil. The number of holes on the polyethylene film with holes is preferably 1-3, and is further preferably 2. The diameter of the holes is preferably 4-8 mm, and is further preferably 6 mm. The application does not have strict requirements for the position of the holes on the polyethylene film, and can be avoided at the packaging position. The thickness of the polyethylene film with holes is preferably 0.03-0.07 mm, and is further preferably 0.07 mm. The length of the polyethylene film with holes is preferably 30-50 cm, and is further preferably 40 cm. The width of the polyethylene film with holes is preferably 20-40 cm, and is further preferably 30 cm. In the specific implementation process of the application, a polyethylene film with holes with a length of 40 cm and a width of 30 cm is preferably used for packaging. The application does not have strict requirements for the source of the polyethylene film with holes, and can be purchased regularly. The application preferably uses each polyethylene film with holes to package 260 g of fresh vegetables.

[0027] In the application, the packaging is preferably heat sealing. The temperature of the heat sealing is preferably 120-180 ℃, and is further preferably 150 ℃. The time of the heat sealing is preferably 3-5 s, and is further preferably 4 s. The pressure of the heat sealing is preferably 90-110 kPa, and is further preferably 101.325 kPa.

[0028] After the packaging treatment, the present application stores the packaged hot pepper in a low-voltage electrostatic field and a low-temperature environment. In the present application, the field strength of the low-voltage electrostatic field is preferably 0.3-2.5 kV / m, further preferably 0.5-2.2 kV / m, more preferably 1.4-2.0 kV / m, and most preferably 1.6-1.8 kV / m. The temperature of the low-temperature environment in the present application is preferably 2-12℃, further preferably 4-10℃, and more preferably 6-8℃. The present application preferably determines the temperature of the low-temperature environment according to the type of fresh vegetables. Specifically, when the fresh vegetables are fresh peppers, the temperature of the low-temperature environment is preferably 8-12℃, and further preferably 10℃. When the fresh vegetables are fresh cabbage, the temperature of the low-temperature environment is preferably 2-6℃, and further preferably 4℃. In the examples, the present application preferably uses a Bomei electrostatic field generating device (purchased from Shandong Bomei Electrical Appliance Technology Co., Ltd.) to provide a low-voltage electrostatic field and a low-temperature environment. The present application uses a low-voltage electrostatic field to promote the imbalance of the electric biological effect in the pepper fruit and reduce the enzyme activity, thereby inhibiting the metabolism of the pepper. The present application can also change the electric field distribution on the surface of the pepper, so that a weak adsorption force is formed to adsorb the surrounding water molecules, reduce the evaporation of water on the surface of the pepper, and maintain a high water content in the pepper fruit and reduce the quality loss.

[0029] The present application uses pepper leaf essential oil combined with low-voltage electrostatic field treatment, and the two treatment methods synergistically inhibit the enzyme activity of pectin and cellulose and reduce the metabolic decomposition of pectin, cellulose and other components, thereby effectively maintaining the texture quality of fresh vegetables, better maintaining the color, texture, nutrition and other qualities of fresh vegetables, reducing the quality loss, and improving the commercial value of peppers.

[0030] In order to further illustrate the present application, a fresh vegetable storage and preservation method provided by the present application is described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0031] Example 1

[0032] 1. Materials

[0033] (1) Fresh pepper fruits 1 h after harvest: uniform size, fresh and tender, no mechanical damage, no pests and diseases, and consistent maturity;

[0034] (2) Polyethylene film bag with two holes (length 40 cm x width 30 cm; thickness 0.07 mm, hole diameter 6 mm);

[0035] (3) Capsicum annuum L. leaf essential oil, the specific preparation process is as follows: 10 kg of Capsicum annuum L. leaf raw material is cut into small pieces of 5-8 mm by hand using a kitchen knife, and then immediately subjected to one-time CO2 supercritical extraction (fixed temperature extraction, each time 10 kg of raw material, extraction pressure 25.0-26.0 MPa, extraction time 6 h, extraction temperature set to 50±2 ℃; separation pressure 16.0-17.0 MPa, temperature 45±2 ℃).

[0036] 2. Fresh Capsicum annuum L. harvested 1 h after harvest is evenly divided into 4 parts, and each part of fresh Capsicum annuum L. is subjected to the following preservation treatment according to the following steps:

[0037] (1) The surface of the Capsicum annuum L. is wiped with paper or soft cloth to remove surface moisture and impurities, and the surface of the Capsicum annuum L. is evenly coated with Capsicum annuum L. leaf essential oil (16 mg / cm 2 ), and then placed in a polyethylene film bag with holes;

[0038] (2) Heat sealing at 150 ℃, 101.325 kPa for 4 s, and storing in a low-voltage electrostatic field with a field strength of 1.6±0.2 kV at 10 ℃.

[0039] Comparative Example 1

[0040] The same batch of Capsicum annuum L. as in Example 1 is used, and each part of fresh Capsicum annuum L. fruit is subjected to the following treatment according to the following steps:

[0041] (1) The surface of the Capsicum annuum L. is wiped with paper or soft cloth to remove surface moisture and impurities, and then placed in a polyethylene film bag with holes;

[0042] (2) Heat sealing at 150 ℃, 101.325 kPa for 4 s, and storing at 10 ℃.

[0043] Comparative Example 2

[0044] The same as Comparative Example 1, the only difference is that after removing the surface moisture and impurities of the Capsicum annuum L., the surface of the Capsicum annuum L. fruit is evenly coated with Capsicum annuum L. leaf essential oil (16 mg / cm 2 ) before being placed in a polyethylene film bag with holes.

[0045] Comparative Example 3

[0046] The same as Comparative Example 1, the only difference is that after heat sealing, the Capsicum annuum L. is stored in an electrostatic field with a field strength of 1.6±0.2 kV.

[0047] Comparative Example 4

[0048] The same as Comparative Example 1, the only difference is that after heat sealing, the Capsicum annuum L. is stored in an electrostatic field with a field strength of 0.5±0.2 kV.

[0049] Comparative Example 5

[0050] The only difference from Comparative Example 1 is that the heat-sealed peppers are stored in an electrostatic field with a field strength of 2.2 ± 0.2 kV after heat-sealing.

[0051] Test Example 1

[0052] After storing the peppers of Example 1 and Comparative Examples 1 to 5 for 7 days, 14 days and 21 days, one sample of peppers was randomly taken from each group, and the following tests were performed according to (1) to (8) to determine the relevant indicators of the peppers stored for 7 days.

[0053] (1) The peppers stored in different ways were individually weighed using a laboratory electronic balance with an accuracy of 0.01 g, and the weight loss rate was calculated. The results are shown in Table 1.

[0054] Table 1. Weight loss rate (%) of peppers under different treatment methods

[0055] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 7 2.27 Ad ]]> 1.67 Ac ]]> 1.02 Ab ]] 1.31 Ab ]]> 1.54 Ab ]]> 0.87 Aa ]] 14 3.38 Bc ]] 1.87 Ab ]]> 1.59 Aa ]]> 1.62 Aa ]]> 1.78 Ab ]]> 1.31 Ba ]]> 21 3.67 Bc ]] 2.54 Bb ]]> 2.35 Bb ]]> 2.47 Bb ]]> 2.69 Bb ]]> 1.79 Ca ]]>

[0056] Note: Different capital letters represent significant differences between storage times, and different lowercase letters represent significant differences between different treatment methods, and the same below.

[0057] As can be seen from Table 1, with the extension of storage time, the weight loss rate of peppers in each treatment group, i.e. the mass loss, showed a gradually increasing trend. After 21 days of storage, the weight loss rate of the peppers stored by the method of the present application (Example 1), i.e. the method of coating with pepper leaf essential oil combined with low-voltage electrostatic field storage, was the lowest, ranging from 0.87% (7 days) to 1.79% (21 days), which was lower than that of the peppers without any treatment (Comparative Example 1), the peppers coated with pepper leaf essential oil (Comparative Example 2) and the peppers stored by low-voltage electrostatic field alone (Comparative Examples 3 to 5). The preservation method of the present application, i.e. the method of coating with pepper leaf essential oil combined with low-voltage electrostatic field storage, can reduce the mass loss of peppers.

[0058] (2) The L*, a* and b* values of the peppers stored in different ways were measured using a color difference meter, and the results are shown in Tables 2 to 4.

[0059] Table 2. L* value of peppers under different treatment methods

[0060] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 51.54 A ]]> 51.54 A ]]> 51.54 A ]]> 51.54 A ]]> 51.54 A ]]> 51.54 A ]]> 7 57.99 Cc ]]> 52.53 Ba ]]> 51.99 Aa ]]> 52.35 Ba ]]> 53.31 Bb ]]> 54.13 Bb ]]> 14 56.70 Bb ]]> 52.44 Ba ]]> 52.42 Ba ]]> 52.68 Ba ]]> 52.98 Ba ]]> 51.77 Aa ]]> 21 56.25 Bc ]]> 56.12 Cc ]]> 54.61 Ca ]]> 54.98 Ca ]]> 55.31 Cb ]]> 54.37 Ba ]]>

[0061] Note: In order to avoid experimental errors caused by individual differences of peppers, one fresh pepper sample of the same batch 1 hour after harvesting was randomly selected from each treatment group before storage, and the L* value was measured as the initial value, i.e. 51.54 in the table.

[0062] Table 3. a* value of peppers under different treatment methods

[0063] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 -4.85 A ]]> -4.85 A ]]> -4.85 A ]]> -4.85 A ]]> -4.85 A ]]> -4.85 A ]]> 7 -3.79 Bb ]]> -3.69 Bb ]]> -3.19 Bb ]]> -3.08 Bb ]]> -2.95 Bc ]]> -4.45 Aa ]]> 14 -2.70 Ca ]]> -2.63 Ca ]]> -1.90 Cb ]] -1.57 Cb ]]> -1.48 Cb ]] -2.81 Ca ]]> 21 -2.92 Cb ]]> -3.28 Ba ]]> -1.16 Cb ]]> -1.01 Cc ]]> -0.98 Cc ]]> -3.98 Ba ]]>

[0064] Note: In order to avoid experimental errors caused by individual differences of the peppers, one fresh pepper sample of the same batch after 1 hour of harvesting was randomly selected before storage in each treatment group, and a* was measured as the initial value, which was -4.85 in the table.

[0065] Table 4 b* value of peppers under different treatment modes

[0066] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 40.45 A ]]> 40.45 A ]]> 40.45 A ]]> 40.45 A ]]> 40.45 A ]]> 40.45 B ]]> 7 45.70 Cd ]] 41.09 Aa ]]> 42.37 Bb ]]> 43.78 Bc ]]> 44.52 Bc ]]> 42.66 Cb ]]> 14 43.14 Bb ]]> 43.33 Cb ]]> 44.16 Cc ]]> 45.62 Cd ]]> 46.32 Cd ]]> 38.29 Aa ]]> 21 45.30 Cc ]]> 42.45 Bb ]]> 45.34 Dc ]]> 46.38 Cd ]]> 47.35 Ce ]]> 41.45 Ba ]]>

[0067] Note: In order to avoid experimental errors caused by individual differences of the peppers, one fresh pepper sample of the same batch after 1 hour of harvesting was randomly selected before storage in each treatment group, and b* was measured as the initial value, which was 40.45 in the table.

[0068] L* value represents black and white color, and the larger the value, the whiter the color; a* value represents red and green color, and the negative value is green, and the larger the absolute value, the greener; b* value represents yellow and blue, and the positive value is yellow, and the larger the value, the yellower. According to Tables 2-4, the L* value, a* value and b* value of the peppers in each treatment group after storage all showed an upward trend, indicating that the color quality of the pepper fruits changed during storage, and gradually changed from dark green to light green or light yellow. After 21 days of storage, the L* value (54.37), a* value (-3.98) and b* value (41.45) of the peppers stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) were the smallest, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage could maintain the original color of the peppers to the greatest extent and delay the yellowing of the peppers.

[0069] (3) The 1x1 cm size pepper samples under different storage modes were subjected to whole texture analysis, and the test conditions were 1 mm / s; the compression degree was 60%; and the trigger force was 0.1 N, and the results are shown in Tables 5-9.

[0070] Table 5 Hardness (N) of peppers under different treatment modes

[0071] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 119.17 D ]]> 119.17 D ]]> 119.17 C ]]> 119.17 C ]]> 119.17 C ]] 119.17 C ]]> 7 75.37 Ba ]]> 91.87 Cb ]]> 99.90 Bc ]] 98.59 Bc ]] 96.52 Bc ]] 109.93 Bd ]] 14 61.48 Ba ]]> 82.88 Bb ]]> 98.54 Bc ]] 96.34 Bc ]]> 95.28 Bc ]]> 108.44 Bd ]]> 21 59.58 Aa ]]> 78.20 Ab ]]> 88.90 Ac ]]> 85.64 Ac ]]> 84.28 Ac ]]> 98.78 Ad ]]>

[0072] Note: In order to avoid experimental errors caused by individual differences of the peppers, one fresh pepper sample of the same batch after 1 hour of harvesting was randomly selected before storage in each treatment group, and the hardness (N) index was measured as the initial value, which was 119.17 in the table.

[0073] Table 6 Cohesiveness (Ratio) of peppers under different treatment modes

[0074] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 0.76 B ]] 0.76 B ]] 0.76 C ]] 0.76 C ]] 0.76 C ]] 0.76 B ]] 7 0.70 Ba ]] 0.69 Aa ]] 0.69 Ba ]] 0.68 Ba ]] 0.67 Ba ]] 0.70 Aa <!-- 5 -->]]> 14 0.81 Cb ]] 0.67 Aa ]] 0.67 Ba ]] 0.66 Ba ]] 0.65 Ba ]] 0.69 Aa ]] 21 0.66 Ab ]] 0.61 Ab ]] 0.56 Aa ]] 0.54 Aa ]]> 0.53 Aa ]] 0.62 Ab ]]

[0075] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvesting was randomly selected before storage in each treatment group, and the cohesiveness (Ratio) index was measured respectively as the initial value, i.e. 0.76 in the table.

[0076] Table 7 Pepper elasticity (mm) under different treatment modes

[0077]

[0078]

[0079] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvesting was randomly selected before storage in each treatment group, and the elasticity (mm) index was measured respectively as the initial value, i.e. 0.78 in the table.

[0080] Table 8 Pepper adhesiveness (N) under different treatment modes

[0081] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 90.03 C ]]> 90.03 D ]]> 90.03 C ]]> 90.03 C ]]> 90.03 C ]]> 90.03 C ]]> 7 52.75 Ba ]]> 63.47 Cb ]]> 68.95 Bb ]] 65.32 Bb ]] 64.52 Bb ]]> 77.37 Bc ]] 14 50.96 Ba ]] 55.22 Bb ]]> 65.92 Bc ]]> 62.31 Bc ]]> 60.57 Bc ]]> 75.18 Bd ]]> 21 39.71 Aa ]]> 47.63 Ab ]]> 49.49 Ab ]]> 48.32 Ab ]]> 45.68 Ab ]]> 61.20 Ac ]]>

[0082] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvesting was randomly selected before storage in each treatment group, and the adhesiveness (N) was measured respectively as the initial value, i.e. 90.03 in the table.

[0083] Table 9 Pepper chewiness (mJ) under different treatment modes

[0084] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 70.06 D ]]> 70.06 D ]]> 70.06 D ]]> 70.06 D ]]> 70.06 D ]]> 70.06 D ]]> 7 38.46 Ba ]]> 47.99 Cb ]]> 50.49 Cc ]]> 48.32 Bb ]]> 46.34 Cb ]]> 58.13 Cd ]]> 14 45.28 Cb ]]> 39.92 Ba ]]> 49.89 Bc ]]> 45.65 Bb ]] 43.26 Bb ]]> 53.57 Bd ]]> 21 30.10 Aa ]]> 34.48 Ab ]]> 34.68 Ab ]]> 32.28 Aa ]]> 30.54 Aa ]]> 46.17 Ac ]]>

[0085] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvesting was randomly selected before storage in each treatment group, and the chewiness (mJ) was measured respectively as the initial value, i.e. 70.06 in the table.

[0086] Hardness (N), cohesiveness (Ratio), elasticity (mm), adhesiveness (N) and chewiness (mJ) all reflect the texture quality of peppers after storage, and directly affect the commodity value of pepper fruits. The values of hardness (N), cohesiveness (Ratio), elasticity (mm), adhesiveness (N) and chewiness (mJ) of peppers in each treatment group after storage all showed a downward trend, indicating that the texture quality of peppers softened. After 21 days of storage, the values of hardness (98.78 N), adhesiveness (61.20 N) and chewiness (46.17 mJ) of peppers stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field (Example 1) were all higher than those of other treatment groups, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of the application can maximize the maintenance of the original texture characteristics of pepper fruits and reduce the degree of softening.

[0087] (4) Take 10 g of each corresponding 1 part of the peppers under different storage methods, filter with gauze after juicing, and determine the soluble solid content in the fruit juice with a portable digital refractometer. The results are shown in Table 10.

[0088] Table 10 Soluble solid content of peppers under different treatment methods (%)

[0089] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 4.98 C ]]> 4.98 C ]] 4.98 C ]] 4.98 B ]]> 4.98 B ]]> 4.98 B ]]> 7 4.68 Ba ]]> 4.90 Cb ]]> 4.94 Cb ]]> 4.93 Bb ]]> 4.92 Bb ]]> 4.94 Bb ]] 14 4.44 Aa ]]> 4.72 Bb ]]> 4.84 Bb ]]> 4.75 Ab ]]> 4.74 Ab ]]> 4.80 Ab ]]> 21 4.36 Aa ]]> 4.58 Aa ]]> 4.68 Ab ]]> 4.62 Ab ]] 4.60 Ab ]] 4.78 Ac ]]

[0090] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvesting was randomly selected in each treatment group before storage, the soluble solid content in the fruit juice was determined, and the average value was taken as the initial solid content, i.e. 4.98% in the table.

[0091] As can be seen from Table 10, the soluble solid content of peppers in each treatment group after storage showed a downward trend, indicating that the nutrients in the fruit were lost during storage. After 21 days of storage, the soluble solid content (4.78%) in the pepper fruit stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) of the present application was higher than that in other treatment groups, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of the present application could maximize the preservation of the original nutritional quality characteristics of the pepper fruit and reduce the loss of nutrients.

[0092] (5) Take 0.5 g of each corresponding 1 part of the pepper powder ground by a liquid nitrogen grinder under different storage methods, add 10 mL of oxalic acid solution for extraction for 5 min, add 0.5 g of activated carbon and centrifuge, take 4 mL of supernatant in a conical flask, titrate with a calibrated 2,6-dichloroindophenol solution until the solution is pink for 15 s without fading, repeat the titration for 3 times, and take the average value. The blank test: replace the supernatant with distilled water, calculate the vitamin C content according to the following formula, and the results are shown in Table 11.

[0093] Vc content (mg / g) = (V-V0) x T x A / W

[0094] In the formula: V represents the volume of 2,6-dichloroindophenol solution consumed in titration of the sample, mL; V0 represents the volume of 2,6-dichloroindophenol solution consumed in titration of the blank, mL; T represents the titration degree of 2,6-dichloroindophenol solution, mg / mL; A represents the dilution multiple; and W represents the sample weight, g.

[0095] Table 11 Vitamin C content of peppers under different treatment methods (mg / 100 g)

[0096] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 141.05 D ]]> 141.05 D ]]> 141.05 D ]]> 141.05 D ]]> 141.05 D ]]> 141.05 D ]]> 7 91.83 Cc ]]> 108.39 Ce ]]> 88.04 Cb ]]> 87.62 Cb ]]> 85.34 Ca ]]> 103.66 Cd ]]> 14 58.69 Ba ]]> 63.90 Bb ]]> 71.95 Bd ]] 69.53 Bc ]]> 67.64 Bc ]]> 75.73 Be ]] 21 51.12 Aa ]]> 59.64 Ab ]] 62.01 Ac ]]> 60.37 Ab ]]> 59.84 Ab ]]> 67.21 Ad ]]>

[0097] Note: To avoid experimental errors caused by individual differences in chili peppers, one fresh chili pepper sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage. The vitamin C content in the fruit was measured and the average value was taken as the initial vitamin C content, which is 141.05 mg / 100g in the table.

[0098] Chili peppers are rich in vitamin C, which reflects their nutritional quality and antioxidant properties. However, vitamin C is extremely unstable and easily oxidized and decomposed by external environmental conditions, leading to a decline in the nutritional quality of the chili peppers. Table 11 shows that the vitamin C content of chili peppers in all treatment groups decreased after storage, indicating oxidative loss of vitamin C during storage. After 21 days of storage, the vitamin C content (67.21 mg / 100g) of chili peppers treated with the chili leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) was higher than that of other treatment groups. This demonstrates that the chili leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of this invention can effectively protect vitamin C, reduce its oxidative loss, and maximize the preservation of the nutritional quality of the chili peppers.

[0099] (6) Take 2g of each chili pepper stored under different conditions, add 15mL of anhydrous ethanol, grind the chili pepper into a homogenate, and extract in a dark, low-temperature environment for 24h. Using anhydrous ethanol as a blank control, measure the absorbance at 470, 649, and 665nm using a UV spectrophotometer. Calculate the contents of chlorophyll a, chlorophyll b, and total chlorophyll using the following formula. The results are shown in Tables 12-14.

[0100] Chlorophyll a(mg / g)=(13.95×A 665 -6.88×A 649 )×V / 1000m;

[0101] Chlorophyll b(mg / g)=(24.96×A 649 -7.32×A 665 )×V / 1000m;

[0102] Chlorophyll(mg / g)=(Chlorophyll a+Chlorophyll b)×V / 1000m;

[0103] In the formula: m represents the sample mass, g; V represents the total volume of the sample extract, mL.

[0104] Table 12 Chlorophyll a content (mg / g) of peppers under different treatments

[0105] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 0.15 C ]] 0.15 B ]] 0.15 C ]] 0.15 C ]] 0.15 C ]] 0.15 B ]] 7 0.11 Aa ]] 0.11 Aa ]] 0.12 Ba ]] 0.11 Ba ]] 0.10 Ba ]] 0.13 Bb ]] 14 0.10 Aa ]] 0.13 Bb ]] 0.11 Ba ]] 0.10 Ba ]] 0.09 Ba ]] 0.14 Bb ]] 21 0.07 Aa ]] 0.09 Ab ]] 0.07 Aa ]] 0.06 Aa ]] 0.05 Aa ]] 0.10 Ab ]]

[0106] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 hour after harvesting was randomly selected before storage in each treatment group, and the average value of chlorophyll a content in the fruit was determined as the initial chlorophyll a content, i.e. 0.15 mg / g in the table.

[0107] Table 13 Chlorophyll b content in pepper fruits under different treatment methods (mg / g)

[0108] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 0.09 A ]] 0.09 A ]] 0.09 A ]] 0.09 A ]] 0.09 B ]] 0.09 A ]] 7 0.08 Aa ]] 0.08 Aa ]] 0.09 Aa ]] 0.08 Aa ]] 0.07 Aa ]] 0.09 Aa ]] 14 0.08 Aa ]] 0.11 Ba ]] 0.10 Ba ]] 0.09 Aa ]] 0.08 Aa ]] 0.11 Aa ]] 21 0.07 Aa ]] 0.08 Aa ]] 0.07 Aa ]] 0.06 Aa ]] 0.05 Aa ]] 0.09 Ab ]]

[0109] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 hour after harvesting was randomly selected before storage in each treatment group, and the average value of chlorophyll b content in the fruit was determined as the initial chlorophyll b content, i.e. 0.09 mg / g in the table.

[0110] Table 14 Total chlorophyll content in pepper fruits under different treatment methods (mg / g)

[0111] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 0.24 B ]] 0.24 B ]] 0.24 B ]] 0.24 C ]] 0.24 C ]] 0.24 B ]] 7 0.18 Aa ]] 0.20 Ab ]] 0.21 Bb ]] 0.19 Ba ]] 0.17 Ba ]] 0.21 Bb ]] 14 0.18 Aa ]] 0.24 Bb ]] 0.21 Ba ]] 0.19 Ba ]] 0.17 Ba ]] 0.25 Bb ]] 21 0.14 Aa ]] 0.17 Ab ]] 0.14 Aa ]] 0.12 Aa ]] 0.10 Aa ]] 0.19 Ab ]]

[0112] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 hour after harvesting was randomly selected before storage in each treatment group, and the average value of total chlorophyll content in the fruit was determined as the initial total chlorophyll content, i.e. 0.24 mg / g in the table.

[0113] The surface of a normally matured pepper fruit is smooth and green in color, and as the storage time is prolonged, the surface color presents a process of changing from green to yellow. Chlorophyll is an important factor affecting the green sensory quality of pepper fruits, and when the chlorophyll content gradually decreases, the yellowing of pepper fruits is the most obvious sign of aging, and the yellowing speed is directly related to the chlorophyll decomposition speed. According to Tables 12-14, the chlorophyll a, chlorophyll b and total chlorophyll contents of peppers in each treatment group after storage all present a downward trend, indicating that chlorophyll components in pepper fruits undergo degradation reactions during storage. After 21 days of storage, the chlorophyll a (0.10 mg / g), chlorophyll b (0.09 mg / g) and total chlorophyll (0.19 mg / g) contents in pepper fruits stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) of the application are higher than those in other treatment groups, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of the application can effectively alleviate the degradation of chlorophyll components in pepper fruits, reduce the degree of fruit yellowing, and effectively maintain the color quality of pepper fruits.

[0114] (7) Take 0.2 g of each corresponding 1 pepper and 10 mL of 95% ethanol under different storage modes, mix, and avoid light to extract for 12 h, then centrifuge at 8000 x g for 10 min at room temperature, take the supernatant, and determine the absorbance of the supernatant at 470 nm, calculate the carotenoid content according to the following formula, and the results are shown in Table 15.

[0115] Carotenoid content (mg / g) = (4.92 x A470nm-0.025 x pa-0.25 x pb) x V / 1000 / m;

[0116] In the formula: pa, mass concentration of chlorophyll a, mg / mL; pb, mass concentration of chlorophyll b, mg / mL; m, mass, g; V, sample volume, L.

[0117] Table 15 Carotenoid content (mg / g) in pepper fruits under different treatment modes

[0118]

[0119]

[0120] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvest was randomly selected before storage for each treatment group, and the carotenoid content was determined as the initial value, i.e., 0.07 mg / g in the table.

[0121] Carotenoids have strong antioxidant capacity and can protect pepper fruits from free radical damage and delay aging. As can be seen from Table 15, the carotenoid content of peppers in each treatment group after storage showed a downward trend, indicating that the carotenoids in the pepper fruits were oxidized and lost during storage. After 21 days of storage, the carotenoid content (0.06 mg / g) in the pepper fruits stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) was higher than that in other treatment groups, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage of the present application could effectively alleviate the loss of carotenoid components in pepper fruits, delay fruit aging, and maintain postharvest quality.

[0122] (8) Take 0.1 g of each corresponding 1 pepper under different storage modes, and use a malondialdehyde content detection kit to detect the malondialdehyde content of the pepper, and the results are shown in Table 16.

[0123] Table 16 Malondialdehyde content (nmol / g) in pepper fruits under different treatment modes

[0124] Storage time (d) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 0 7.45 A ]]> 7.45 A ]]> 7.45 B ]]> 7.45 A ]]> 7.45 A ]]> 7.45 B ]]> 7 7.58 Ac ]]> 8.85 Bd ]]> 6.62 Ab ]]> 6.95 Ab ]]> 7.05 Ab ]]> 5.61 Aa ]]> 14 8.99 Ba ]] 9.40 Cb ]] 10.14 Cb ]] 11.24 Bc ]]> 12.05 Bc ]]> 8.80 Ca ]] 21 9.93 Cb ]] 8.18 Ba ]] 10.26 Cc ]] 11.38 Bd ]] 12.84 Be ]] 7.86 Ba ]]>

[0125] Note: In order to avoid experimental errors caused by individual differences of peppers, 1 fresh pepper sample of the same batch 1 h after harvest was randomly selected from each treatment group before storage, and the carotenoid content was measured as the initial value, i.e. 0.07 mg / g in the table.

[0126] Malondialdehyde is a product of membrane lipid peroxidation, and its content can reflect the degree of oxidative stress and membrane lipid peroxidation damage of peppers, and is one of the indicators for measuring the degree of pepper aging. As can be seen from Table 16, the malondialdehyde content of peppers in each treatment group after storage showed an upward trend, indicating that the pepper fruits were subjected to oxidative damage during storage. After 21 days of storage, the malondialdehyde content (7.86 nmol / g) in the pepper fruits stored by the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 1) was lower than that in the other treatment groups, indicating that the pepper leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of the present application can effectively reduce the malondialdehyde content in the pepper fruits, reduce oxidative damage, and maximize the quality of the pepper fruits.

[0127] Example 2

[0128] Example 1, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0129] Comparative Example 6

[0130] Comparative Example 1, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0131] Comparative Example 7

[0132] Comparative Example 2, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0133] Comparative Example 8

[0134] Comparative Example 3, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0135] Comparative Example 9

[0136] Comparative Example 4, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0137] Comparative Example 10

[0138] Comparative Example 5, except that the fresh pepper fruits 1 h after harvest were replaced by fresh cabbage, and the temperature during storage was 4°C.

[0139] Test Example 2

[0140] After 7, 14, 21 and 28 days of storage of postharvest heading cabbage in Examples 2 and Comparative Examples 6-10, the weight loss rate, L* value, a* value, b* value, hardness, cohesiveness, elasticity, adhesiveness and chewiness of the heading cabbage under different treatments were measured in accordance with the method of Test Example 1. The results are shown in Tables 17-25.

[0141] Table 17 Weight loss rate (%) of head cabbage under different treatment methods

[0142] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 7 5.28 Aa ]]> 5.13 Aa ]]> 5.00 Da ]]> 5.14 Aa ]] 5.26 Aa ]] 4.34 Aa ]]> 14 7.76 Bb ]] 7.34 Bab ]]> 7.10 Cab ]] 7.68 Bb ]] 7.72 Bb ]] 5.64 Aa ]]> 21 8.97 Ba ]] 8.86 Ca ]] 8.81 Ba ]] 8.92 Ca ]]> 8.94 Ca ]]> 8.43 Ba ]]> 28 12.10 Ca ]]> 11.56 Da ]]> 11.38 Aa ]] 11.78 Da ]] 11.92 Da ]]> 11.23 Ca ]]>

[0143] As shown in Table 17, the weight loss rate (i.e., quality loss) of the head cabbage in each treatment group gradually increased with the extension of storage time. After 28 days of storage, the head cabbage treated with the pepper leaf essential oil coating combined with low-voltage electrostatic field storage (Example 2) had the lowest weight loss rate, ranging from 4.34% (7 days) to 11.23% (28 days), which was lower than that of the head cabbage without any treatment (Comparative Example 6), pepper leaf essential oil coating (Comparative Example 7), and low-voltage electrostatic field treatment alone (Comparative Examples 8-10). The pepper leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of the present invention can reduce the quality loss of head cabbage.

[0144] Table 18 L* values ​​of head cabbage under different treatment methods

[0145] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 76.67 C ]]> 76.67 C ]]> 76.67 C ]]> 76.67 D ]] 76.67 D ]]> 76.67 C ]] 7 75.76 BCa ]] 75.52 BCa ]]> 75.42 Ba ]] 74.35 Ca ]] 74.26 Ca ]] 75.03 Ba ]] 14 74.09 ABa ]]> 74.58 Ba ]] 74.69 Ba ]]> 73.89 Ba ]]> 73.72 Ba ]]> 74.22 Aa ]]> 21 74.15 ABb ]]> 74.62 Bb ]]> 74.90 Bb ]] 72.96 Ba ]]> 72.35 Ba ]]> 73.42 Ab ]]> 28 72.39 Ab ]]> 72.05 Ab ]]> 72.05 Ab ]]> 71.24 Aa ]]> 71.05 Aa ]]> 73.16 Ac ]]>

[0146] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the L* value was measured as the initial value, which is 76.67 in the table.

[0147] Table 19. a* values ​​of head cabbage under different treatment methods

[0148] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 -7.96 C ]] -7.96 C ]]> -7.96 B ]]> -7.96 C ]]> -7.96 C ]] -7.96 A ]] 7 -9.24 BCa ]]> -9.45 BCa ]]> -9.40 Aa ]]> -9.56 Ba ]]> -9.62 Ba ]]> -9.11 ABa ]]> 14 -9.72 ABa ]]> -9.78 ABa ]]> -9.71 Aa ]]> -9.89 Ba ]]> -9.95 Ba ]]> -10.13 BCa ]]> 21 -9.98 ABa ]]> -10.02 ABa ]] -9.93 Aa ]] -10.52 Aa ]] -10.85 Aa ]]> -10.06 BCa ]]> 28 -10.93 Aa ]]> -11.05 Aa ]]> -10.57 Aa ]]> -11.20 Aa ]]> -11.35 Aa ]]> -10.51 Ca ]]>

[0149] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch, harvested 1 hour after harvest, was randomly selected from each treatment group before storage, and the a* value was measured as the initial value, which is -7.96 in the table.

[0150] Table 20 b* values ​​of head cabbage under different treatments

[0151] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 24.96 A ]]> 24.96 A ]]> 24.96 A ]]> 24.96 A ]]> 24.96 A ]]> 24.96 A ]]> 7 30.24 Ba ]]> 29.56 Ba ]]> 29.42 Ba ]]> 29.65 Ba ]]> 29.73 Ba ]]> 29.41 Ba ]]> 14 30.58 Ba ]]> 30.95 Ba ]]> 29.97 ABa ]] 31.05 Bb ]]> 31.62 Cb ]]> 31.01 Bb ]]> 21 32.63 Ba ]]> 32.54 Ca ]]> 32.08 BCa ]]> 32.64 Ca ]]> 32.68 Da ]]> 32.45 Ca ]]> 28 35.94 Cb ]]> 33.35 Ca ]]> 33.26 Ca ]]> 33.42 Ca ]]> 33.82 Da ]]> 32.69 Ca ]]>

[0152] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch, harvested 1 hour prior, was randomly selected from each treatment group before storage, and the b* value was measured as the initial value, which is 24.96 in the table.

[0153] As shown in Tables 18-20, the L* and a* values ​​of the head cabbage in each treatment group showed a decreasing trend after storage, while the b* value showed an increasing trend. This indicates that the color quality of the head cabbage changed during storage, gradually changing from light green to light yellow. After 28 days of storage, the head cabbage treated with the chili leaf essential oil coating combined with low-pressure electrostatic field storage (Example 2) had the highest L* value (73.16) and a* value (-10.51), and the lowest b* value (32.96). This demonstrates that the chili leaf essential oil coating combined with low-pressure electrostatic field storage preservation method of the present invention can maintain the original color of the head cabbage to the greatest extent and delay its yellowing.

[0154] Table 21. Hardness (N) of head cabbage under different treatment methods

[0155] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 45.62 D ]]> 45.62 C ]]> 45.62 D ]]> 45.62 D ]]> 45.62 D ]]> 45.62 D ]]> 7 41.02 Ca ]]> 41.28 Ba ]]> 41.51 CDa ]]> 41.23 Ca ]]> 41.08 Ca ]]> 41.34 Ca ]]> 14 39.31 CDa ]]> 40.25 Ba ]]> 40.29 Ba ]]> 39.62 Ba ]]> 39.53 Ba ]]> 40.26 Ba ]]> 21 37.93 ABa ]] 38.96 Aa ]]> 39.38 Ba ]]> 38.45 Aa ]]> 38.12 Aa ]]> 38.30 Aa ]]> 28 36.38 Aa ]]> 37.02 Aa ]] 37.16 Aa ]]> 36.85 Aa ]]> 36.74 Aa ]]> 37.62 Aa ]]>

[0156] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the hardness (N) index was measured as the initial value, which is 45.62 in the table.

[0157] Table 22 Cohesiveness (Ratio) of Head Cabbage under Different Treatments

[0158] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 0.51 AB ]] 0.51 B ]] 0.51 A ]] 0.51 A ]] 0.51 A ]] 0.51 A ]] 7 0.45 Aa ]]> 0.47 A ]] 0.46 Aa ]] 0.50 Aa ]] 0.52 Aa ]] 0.48 Aa ]] 14 0.58 BCa ]] 0.59 Ba ]] 0.58 ABa ]] 0.62 Ba ]] 0.65 Ba ]] 0.62 ABa ]] 21 0.64 Ca ]] 0.66 Ba ]] 0.68 BCa ]] 0.70 Ba ]] 0.73 Ba ]] 0.53 Aa ]] 28 0.66 Ca ]] 0.71 Ba ]] 0.76 Ca ]] 0.79 Ba ]] 0.80 Cb ]] 0.74 Ba ]]

[0159] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the cohesiveness (Ratio) index was measured as the initial value, which is 0.51 in the table.

[0160] Table 23 Elasticity of Head Cabbage under Different Treatment Methods (mm)

[0161] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 0.72 A ]] 0.72 A ]] 0.72 A ]] 0.72 A ]] 0.72 B ]] 0.72 A ]] 7 0.70 Aab ]] 0.71 Ab ]] 0.73 Ab ]] 0.70 Ab ]] 0.71 Bb ]] 0.64 Aa ]] 14 0.68 Aa ]] 0.69 Aa ]] 0.71 Aa ]] 0.69 Aa ]] 0.68 Aa ]] 0.69 Aa ]] 21 0.75 Aa ]] 0.74 Aa ]] 0.76 Aa ]] 0.73 Aa ]] 0.74 Ba ]] 0.65 Aa ]] 28 0.69 Aa ]] 0.72 Aa ]] 0.78 Aa ]] 0.75 Ba ]] 0.76 Ba ]] 0.86 Bb ]]

[0162] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the elasticity (mm) index was measured as the initial value, which is 0.72 in the table.

[0163] Table 24. Stickiness (N) of head cabbage under different treatment methods

[0164]

[0165]

[0166] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the adhesiveness (N) index was measured as the initial value, which is 37.58 in the table.

[0167] Table 25 Chewability (mJ) of Head Cabbage under Different Treatments

[0168] Storage time (d) Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 0 16.86 B ]]> 16.86 B ]]> 16.86 B ]]> 16.86 B ]] 16.86 B ]]> 16.86 B ]] 7 12.85 Aa ]]> 13.59 Aa ]]> 14.31 Aa ]] 14.89 Aa ]] 14.92 Aa ]] 12.49 Ba ]]> 14 15.59 Ba ]]> 16.02 Ba ]]> 16.58 Ba ]]> 17.05 Ba ]] 17.35 Ba ]]> 17.35 Aa ]]> 21 18.22 Cb ]]> 19.81 Cb ]]> 20.42 Cc ]] 21.05 Cc ]] 21.85 Cc ]]> 13.41 Ba <!-- 12 -->]]> 28 16.54 Ba ]]> 20.56 Cb ]]> 22.36 Cc ]]> 22.56 Cc ]]> 22.84 Cc ]] 23.92 Ad ]]

[0169] Note: To avoid experimental errors caused by individual differences in head cabbage, one fresh head cabbage sample from the same batch was randomly selected 1 hour after harvest from each treatment group before storage, and the chewiness (mJ) index was measured as the initial value, which is 16.86 in the table.

[0170] Hardness (N), cohesiveness (Ratio), elasticity (mm), adhesiveness (N), and chewiness (mJ) all reflect the texture quality of cabbage after storage and directly affect its commercial value. After storage, the hardness (N) values ​​of cabbage in all treatment groups showed a significant decreasing trend, indicating that the cabbage softened. After 28 days of storage, the cabbage treated with the chili leaf essential oil coating combined with low-voltage electrostatic field storage (Example 2) had a higher hardness value than other treatment groups, demonstrating that the chili leaf essential oil coating combined with low-voltage electrostatic field storage preservation method of this invention can maintain the original texture characteristics of cabbage to the greatest extent and reduce its softening degree.

[0171] As can be seen from the above, this invention utilizes chili leaf essential oil coating combined with low-temperature and low-pressure electrostatic field preservation technology to reduce the loss of nutrients in fresh vegetables, minimize moisture loss, maintain the textural properties of vegetables, and delay the oxidative decomposition of chlorophyll components. This significantly preserves the original color of fresh vegetables, delays yellowing, inhibits physiological metabolic activities, slows the consumption of soluble solids, inhibits membrane lipid peroxidation, reduces malondialdehyde accumulation, and improves the preservation effect of fresh vegetables. Although the above embodiments provide a detailed description of the invention, they are only a part of the embodiments, not all of them. Other embodiments can be obtained based on these embodiments without creative intent, and all such embodiments fall within the scope of protection of this invention.

Claims

1. A method for storing and preserving fresh vegetables, characterized in that, It consists of the following steps: After coating the surface of fresh vegetables with chili leaf essential oil, store them in a low-voltage electrostatic field and low-temperature environment. Before storing the fresh vegetables covered with chili leaf essential oil in a low-voltage electrostatic field and low-temperature environment, the vegetables are packaged. The packaging process involves encapsulating fresh vegetables coated with chili leaf essential oil in a perforated polyethylene film. The fresh vegetables are fresh chili peppers or fresh head cabbage; The chili leaf essential oil is a product obtained by supercritical CO2 extraction of chili leaves. The dosage of the chili leaf essential oil is 15-17 mg / cm³. 2 ; The fresh chili peppers are stored at a temperature of 8-12°C in a low-temperature environment. The fresh head cabbage is stored at a temperature of 4-6°C in a low-temperature environment; The field strength of the low-voltage electrostatic field is 1.6 kV / m.

2. The storage and preservation method according to claim 1, characterized in that, The perforated polyethylene film has a length of 30-50cm, a width of 20-40cm, and a thickness of 0.03-0.07mm.

3. The storage and preservation method according to claim 1, characterized in that, The number of holes on the perforated polyethylene film is 1 to 3, and the diameter of each hole is 7 to 8 mm.

4. The storage and preservation method according to claim 1, characterized in that, The encapsulation is heat-sealed; The heat sealing temperature is 120~180℃, the time is 3~5s, and the pressure is 90~110kPa.

5. The storage and preservation method according to claim 1, characterized in that, The fresh vegetables mentioned are those harvested 0-2 hours after picking.

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