Method for reducing nitrite accumulation in postharvest fruit and vegetable storage

Abstract

The invention relates to the technical field of fruit and vegetable storage, and discloses a method for reducing nitrite accumulation in postharvest fruit and vegetable storage, which comprises the following steps: soaking fruits and vegetables with an argon-rich solution or spraying the fruits and vegetables with the argon-rich solution, and storing the fruits and vegetables; the concentration of argon in the solution rich in argon is 1%-3% (v / v); the solution is water; the storage temperature is 4-30 DEG C, and the humidity is 40-70%. The method for reducing nitrite accumulation in postharvest fruit and vegetable storage is low in cost, convenient to operate and use, simple in argon preparation operation, low in cost and wide in application range due to multiple acquisition modes; the method for reducing nitrite accumulation in postharvest fruit and vegetable storage is clean, green, colorless and odorless, does not cause color attachment to fruit and vegetable shells, is stable in chemical property, does not burn or explode, and does not generate adverse effects on human bodies or environments; in addition, the argon is high in liquefaction temperature, easy to liquefy, and easy to store and transport.

Description

Technical Field

[0001] The invention belongs to the technical field of fruit and vegetable storage, and in particular relates to a method for reducing nitrite accumulation in post-harvest fruit and vegetable storage. Background Art

[0002] During the cultivation and transportation of fruits and vegetables, nitrates are easily enriched. Excessive nitrates do not cause any harm to the vegetables themselves, but they are potentially harmful to human health after being ingested by the human body. The harm is mainly manifested through nitrites. This is because after nitrates enter the human body, they can be reduced to nitrites under the action of bacteria in the human body. Nitrite is a strong oxidant that can oxidize the low-valent iron in blood hemoglobin to high-valent iron, forming methemoglobin that cannot transport oxygen, thereby affecting the oxygen transport and causing human hypoxia poisoning, that is, methemoglobinosis. Nitrite is very toxic and is more harmful to infants and young children. In severe cases, it can be life-threatening. Secondly, when nitrites are in an acidic environment such as the presence of secondary amines, tertiary amines, amides and amino acids in the stomach, they can form nitrosamines with strong carcinogenic effects. Among the more than 120 nitrosamine compounds that have been discovered, 75% of nitrosamines have been confirmed to be carcinogenic. The incidence of many endemic gastric cancers and other digestive tract cancers is closely related to the pollution of vegetable nitrates. Although the harm of nitrate to human body is relatively hidden, its toxicity is even greater than the harm of pesticide residue to human body. Therefore, the content of nitrate and nitrite is one of the must-check items for declaring high-quality vegetables such as organic, green and pollution-free.

[0003] At present, the limit of nitrite in pollution-free fruits and vegetables formulated by my country is no more than 4mg / kg. The methods that can reduce nitrite on the market mainly include chemical method and low temperature method. Among them, the strong oxidant used in the chemical method will react with nitrite to leave a variety of chemical substances, which may cause secondary harm to the human body. The low temperature method consumes a lot of energy and is easy to cause pollution to the atmosphere.

[0004] Therefore, developing a safe, efficient, green and pollution-free method for reducing nitrite accumulation in post-harvest fruits and vegetables has become a technical problem to be solved urgently in this field.

[0005] The present invention unexpectedly discovered that storing fruits and vegetables after soaking and spraying them in an argon-rich aqueous solution can significantly reduce the nitrite content of the fruits and vegetables during storage, which is of great significance for improving the edible safety of fruits and vegetables and maintaining and improving the nutritional quality of fruits and vegetables.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] A method for reducing nitrite accumulation in storage of harvested fruits and vegetables comprises soaking the fruits and vegetables in a solution rich in argon or spraying the fruits and vegetables with a solution rich in argon before storage.

[0009] As a preferred embodiment of the present invention, the concentration of argon in the argon-rich solution is 1% to 3% (v / v).

[0010] As a preferred embodiment of the present invention, the solution is water.

[0011] As a preferred embodiment of the present invention, the storage temperature is 4°C to 30°C, and the humidity is 40% to 70%.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The method for reducing nitrite accumulation in storage of post-harvest fruits and vegetables of the present invention is not only low in cost but also convenient to operate and use. The preparation of argon is simple and low in cost, and there are many ways to obtain it. Therefore, the method has a wide range of applications and is applicable to most fruits and vegetables on the market.

[0014] The method for reducing nitrite accumulation in storage of post-harvest fruits and vegetables is clean and green, colorless and tasteless, will not color the shells of fruits and vegetables, and has stable chemical properties, will not burn or explode, and will not have adverse effects on human body or environment; in addition, argon has a high liquefaction temperature, is easy to liquefy, and is easy to store and transport. DETAILED DESCRIPTION

[0015] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0016] The determination of nitrite content in each treatment group and control group in this specific example was carried out by the following method; the determination of nitrite content was based on "Yan Pingmei, Xue Wentong, Zhang Hui, et al. Study on the changes of nitrite in different stored vegetables. Food Science, 2006, 2(6): 242-246"

[0017] A method for reducing nitrite accumulation in storage of harvested fruits and vegetables, wherein the fruits and vegetables are soaked in an argon-rich solution or sprayed with an argon-rich solution before storage. The argon concentration in the argon-rich solution is 1% to 3% (v / v). The solution is water. The storage temperature is 4°C to 30°C, and the humidity is 40% to 70%.

[0018] Example 1: Reducing the accumulation of nitrite after harvesting lettuce

[0019] Fresh lettuces purchased from Fengyang Vegetable Market were used as materials. 120 lettuces were purchased from the same batch and randomly divided into 4 groups. They were immersed in aqueous solutions with different concentrations of argon-rich gas, dried naturally, and stored in polyethylene bags with a thickness of 0.04 mm at 12°C and a humidity of 60%:

[0020] Control group: water;

[0021] Treatment group 1: argon-enriched aqueous solution, argon concentration was 1%;

[0022] Treatment group 2: argon-enriched aqueous solution, argon concentration was 2%;

[0023] Treatment group 3: argon-enriched aqueous solution, argon concentration was 3%;

[0024] Table 1. Effects of different concentrations of argon-rich aqueous solutions on nitrite content during storage of lettuce

[0025]

[0026] The experimental results showed that the nitrite content gradually increased during the 6-day storage, but the nitrite content of treatment group 3 showed a downward trend on the second day, and the nitrite content of each treatment group was lower than that of the control group, with treatment group 3 being the most significant, indicating that the argon-rich aqueous solution has an inhibitory effect on the formation of nitrite during the storage of lettuce.

[0027] Example 2: Reducing the accumulation of nitrite after Chinese cabbage is harvested

[0028] Fresh Chinese cabbage purchased from Fengyang Vegetable Market was used as the material. 24 Chinese cabbages were purchased from the same batch and randomly divided into 4 groups. The leaves were sprayed with the following argon-rich aqueous solutions of different concentrations, dried naturally, and stored in polyethylene bags with a thickness of 0.04 mm at 10°C and a humidity of 40%:

[0029] Control group: water;

[0030] Treatment group 1: argon-enriched aqueous solution, argon concentration was 1%;

[0031] Treatment group 2: argon-enriched aqueous solution, argon concentration was 2%;

[0032] Treatment group 3: argon-enriched aqueous solution, argon concentration was 3%;

[0033] Table 2. Effects of different concentrations of argon-enriched aqueous solutions on nitrite content in stored Chinese cabbage

[0034]

[0035] The above results show that the nitrite content of Chinese cabbage increases during storage, reaches a peak on the sixth day of storage, and then decreases slightly or remains flat. The nitrite content in the corresponding treatment groups is lower than that in the control group, among which treatment group 3 is the most significant. The nitrite content is the lowest after refrigeration for 10 days, which is 77.1% of the control group, and treatment groups 2 and 1 are 86.4% and 90.7% of the control group, respectively. This shows that the argon-rich aqueous solution can delay the accumulation of nitrite in Chinese cabbage during storage.

[0036] Example 3: Reducing the accumulation of nitrite after picking broccoli

[0037] Fresh broccoli purchased from Fengyang Vegetable Market was used as the material. 36 broccoli were purchased from the same batch and randomly divided into 4 groups. They were immersed in the following argon-rich aqueous solutions of different concentrations, dried naturally, and stored in 4.5L perforated Lock & Lock boxes at 30°C and 70% humidity:

[0038] Control group: water;

[0039] Treatment group 1: aqueous solution with argon gas, argon concentration of 1%;

[0040] Treatment group 2: aqueous solution with argon gas, argon concentration was 2%;

[0041] Treatment group 3: aqueous solution with argon gas, argon concentration of 3%;

[0042] Table 3. Effects of different concentrations of argon-enriched aqueous solutions on nitrite content in broccoli during storage

[0043]

[0044]

[0045] The experimental results showed that the change trend of nitrite content in broccoli in the control group and the treatment group was roughly the same, among which nitrite continued to accumulate, the control group showed a sharp upward trend, while the change rate of the treatment group was relatively low, and the nitrite content in the treatment group was lower than that in the control group. In summary, argon-rich aqueous solution can inhibit the accumulation of nitrite content in broccoli during storage.

[0046] Example 4: Reducing the accumulation of nitrite after blueberry picking

[0047] Fresh blueberries purchased from Fengyang Fresh Orchard were used as the material. 360 blueberries were purchased from the same batch and randomly divided into 4 groups. The following argon water solutions of different concentrations were sprayed on the fruits 1 to 3 times a day, and naturally dried. The fruits were placed in a 4.5L Lock & Lock box with holes and stored at 4°C and 60% humidity. Nitrite was detected on the 6th day after treatment.

[0048] Control group: water;

[0049] Treatment group 1: argon-enriched aqueous solution, argon concentration was 1%;

[0050] Treatment group 2: argon-enriched aqueous solution, argon concentration was 2%;

[0051] Treatment group 3: argon-enriched aqueous solution, argon concentration was 3%;

[0052] Table 4. Effects of different concentrations of argon aqueous solution on nitrite content in blueberry storage

[0053]

[0054] The experimental results showed that all treatment groups could reduce the accumulation of nitrite during blueberry storage, indicating that argon-rich aqueous solutions can effectively slow down the accumulation of nitrite during blueberry storage.

[0055] Example 5: Reducing the accumulation of nitrite after picking European plum fruit

[0056] Using European plum fruit purchased from Fengyang Fresh Orchard as the material, 60 European plum fruits purchased from the same batch were randomly divided into 4 groups, and immersed in the following argon water solution with different concentrations for 10 minutes every day, dried naturally, and stored in a 4.5L lock and lock box with holes at room temperature 25℃ and humidity 70%. Nitrite was tested on the 5th day after treatment.

[0057] Control group: water;

[0058] Treatment group 1: argon-enriched aqueous solution, argon concentration was 1%;

[0059] Treatment group 2: argon-enriched aqueous solution, argon concentration was 2%;

[0060] Treatment group 3: argon-enriched aqueous solution, argon concentration was 3%;

[0061] Table 5. Effects of different concentrations of argon-rich aqueous solutions on nitrite content during storage of European plum fruit

[0062]

[0063] The experimental results showed that the treatment groups were able to reduce the accumulation of nitrite during the storage of European prunes, indicating that the argon-rich aqueous solution can effectively slow down the accumulation of nitrite during the storage of European prunes.

[0064] According to the above five embodiments, it can be concluded that soaking or spraying fruits and vegetables with an aqueous solution rich in argon (1% to 3% concentration) can significantly inhibit the accumulation of nitrite during storage. The specific experimental data are as follows:

[0065] Lettuce: After 6 days, the nitrite content of the 3% argon treatment group (3.38 mg / kg) was 40.4% lower than that of the control group (5.67 mg / kg) [Table 1];

[0066] Chinese cabbage: The content of the 3% argon treatment group was 3.41 mg / kg after 10 days, which was 22.9% lower than that of the control group (4.42 mg / kg) [Table 2];

[0067] Blueberry: The content of the 3% argon treatment group was 2.19 mg / kg on the 6th day, which was 23.7% lower than that of the control group (2.87 mg / kg) [Table 4]. This suggests that argon may play a role by inhibiting microbial activity or slowing down the metabolic process of nitrate reduction to nitrite.

[0068] In addition, it is worth mentioning that the fruits and vegetables are soaked in the argon-rich aqueous solution or the argon-rich aqueous solution is sprayed on the fruits and vegetables. The soaking treatment time of fresh fruits and vegetables is 1 to 10 days, 1 to 30 minutes per day; the spraying treatment time is 1 to 10 days, 1 to 3 times per day; the environmental humidity of the fruits and vegetables is 40% to 70% (including 40% and 70%); the fruits and vegetables are placed at 4°C to 30°C (including 4°C and 30°C).

[0069] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for reducing nitrite accumulation in post-harvest fruit and vegetables during storage, characterized in that: The fruits and vegetables are soaked in a solution rich in argon or sprayed with a solution rich in argon before storage.

2. The method for reducing nitrite accumulation in storage of post-harvest fruits and vegetables according to claim 1, characterized in that: The concentration of argon in the argon-rich solution is 1% to 3% (v / v).

3. The method for reducing nitrite accumulation in storage of post-harvest fruits and vegetables according to claim 1, characterized in that: The solution is water.

4. The method for reducing nitrite accumulation in storage of post-harvest fruits and vegetables according to claim 1, characterized in that: The storage temperature is 4° C. to 30° C., and the humidity is 40% to 70%.

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