A kind of atmosphere-controlled preservative for finished grain and preparation method thereof

Abstract

The present application relates to the field of grain storage, and specifically discloses a kind of gas-controlled preservative for finished grain and its preparation method. The gas-controlled preservative for finished grain includes the following components in parts by weight: 40-60 parts of iron powder; 3-5 parts of activated carbon powder; 3-5 parts of salt; 20-30 parts of water-releasing agent; the preparation method of the water-releasing agent is as follows: water absorption: the hygroscopic agent and water are mixed according to the mass ratio of 1: (1-1.5), and then divided into 60-80wt% of component A and 20-40wt% of component B, and component B is reserved; coating: component A is immersed in plant essential oil, and taken out for use after 1-10min. The present application prolongs the water release cycle, delays the release of water, so that the water will not be concentrated in the reaction of iron powder and oxygen in a short time, and then delays the heat production rate, so the present application can achieve a thorough reduction of oxygen content without causing excessive temperature increase.

Description

Technical Field

[0001] The present application relates to the field of grain storage, and more specifically, to a controlled atmosphere preservative for finished grains and a preparation method thereof. Background Art

[0002] Controlled atmosphere preservatives have the function of changing the gas composition of the storage environment and regulating the storage environment to a low-oxygen state, which is beneficial to the storage of dry goods such as Chinese medicinal materials, tobacco, nuts, tea, grains, etc.

[0003] The Chinese patent with the publication number CN1759681A discloses a green multifunctional tobacco insecticide and mildew preventer, the composition and weight percentage of the insecticide and mildew preventer are oxygen absorber 10-90%, moisturizer 1-30%, cathode material 0.1-20%, retarder 0.1-10%, salt 0.1-30%, water 1-0%. The oxygen absorber is selected from pyrite powder or reduced iron powder, the moisturizer is selected from pearlite powder or bentonite, the cathode material is selected from carbon powder, copper powder, copper salt or lead salt, the retarder is selected from sulfite, ascorbic acid or hydroxylamine hydrochloride, and the salt is selected from chloride or sulfate.

[0004] The mildew inhibitor disclosed in the above patent belongs to the atmosphere conditioning preservative. The oxygen absorber absorbs oxygen and corrodes, consuming oxygen in the air, playing the role of insecticide and mildew prevention. In the storage of bagged finished grains such as rice and flour, the oxygen content needs to be completely reduced to below 2%, and the temperature and humidity cannot be excessively increased during the atmosphere control process.

[0005] When the controlled atmosphere preservative was implemented, it was found that it was not well suited for the storage and preservation of bagged finished grains such as rice and flour. The reason is that within a short period of time after the controlled atmosphere preservative was added, the oxygen absorber reacted violently with water. For example, iron powder reacted with water and oxygen to produce iron hydroxide, which generated a large amount of heat, causing the temperature to rise rapidly. Due to the increase in temperature, the iron hydroxide was partially dehydrated to produce iron oxide and water. The regeneration of water is not conducive to the storage of finished grains. If the amount of controlled atmosphere preservative added is reduced in order to reduce heat generation, the oxygen content will not be completely reduced. Summary of the invention

[0006] In order to completely reduce the oxygen content without causing excessive temperature increase, the present application provides a controlled atmosphere preservative for finished grains and a preparation method thereof.

[0007] In the first aspect, the present application provides a controlled atmosphere preservative for finished grains, which adopts the following technical solution:

[0008] A modified atmosphere preservative for finished grains, comprising the following components in parts by weight:

[0009] 40-60 parts of iron powder;

[0010] 3-5 parts of activated carbon powder;

[0011] 3-5 parts salt;

[0012] 20-30 parts of water release agent;

[0013] The preparation method of the water-releasing agent is as follows:

[0014] Water absorption: Mix the moisture absorbent and water in a mass ratio of 1:(1-1.5), and then divide them into 60-80wt% of component A and 20-40wt% of component B, and keep component B for later use;

[0015] Coating: Immerse component A in plant essential oil for 1-10 minutes and then take it out for use.

[0016] By adopting the above technical solution and utilizing the principle of electrochemical corrosion, iron powder reacts with water and oxygen to obtain iron hydroxide, which consumes oxygen in the environment and is beneficial to the storage and preservation of finished grains.

[0017] Among them, the desiccant is used as a water carrier to fully absorb water so that the water can be slowly released for the oxidation reaction of iron powder. More importantly, after most of the desiccant surfaces are soaked with plant essential oils, a thin oil film is formed to hinder the release of water.

[0018] The coating step has the following advantages: first, after the controlled atmosphere preservative is added, the oil film of the plant essential oil will gradually disappear due to its strong volatility, thereby extending the water release cycle, so that the water will not be concentrated in a short period of time to participate in the reaction between iron powder and oxygen, so it is not easy to produce excessive heat in a short period of time. By delaying the heat production rate, the present application can completely reduce the oxygen content without causing excessive temperature increase; second, the plant essential oil has a certain insecticidal and antibacterial effect after volatilization, which is beneficial to the preservation of finished grains.

[0019] Optionally, the preparation method of the water-releasing agent further comprises a modification step, and the specific process is as follows: adding the desiccant to a 5wt% KH570 solution, stirring at high speed for 5-10 minutes, heating to 50-60°C, and then keeping warm for 15-20 minutes, and finally filtering and drying to obtain a modified desiccant.

[0020] By adopting the above technical solution, the lipophilicity of the desiccant is improved after the surface treatment with KH570, so that the plant essential oil can infiltrate the surface of the desiccant to form an oil film.

[0021] It should be noted that, compared with the modification performed to improve dispersibility, the modification time of the desiccant in the present application is shorter and the concentration of the KH570 solution is lower, so that the effect of the modification step on the water absorption of the desiccant is minimized to ensure that it can absorb sufficient water.

[0022] Optionally, the preparation process of the moisture absorbent is as follows:

[0023] Firstly, the vermiculite is immersed in a hydrochloric acid solution, heated to 70-80°C, stirred continuously for 30-50 minutes, then taken out, washed with water, dried, and finally roasted to obtain a moisture absorbent.

[0024] By adopting the above technical solution, the vermiculite is acid-modified and becomes porous, with an increased specific surface area and excellent water absorption. The weight water absorption rate exceeds 200%. Even after subsequent modification with KH570, it can still meet the target water absorption requirements.

[0025] Optionally, in the coating step, component A is divided into multiple portions with equal mass ratio, and each portion of component A is soaked in the plant essential oil for different times.

[0026] Optionally, component A is divided into 5 parts by mass, and the time for each part of component A to be soaked in the plant essential oil is 1 min, 3 min, 5 min, 7 min and 10 min, respectively.

[0027] By adopting the above technical solution, generally speaking, the soaking time of plant essential oil is long, and the oil film formed on the surface is relatively thick, so that multiple components A have oil films of different thicknesses. Therefore, during the use of the controlled atmosphere preservative, the water release cycles of different water-releasing agents are further significantly staggered, which is conducive to the slow release of water and ensures that the temperature does not rise excessively.

[0028] Optionally, the plant essential oil is thyme essential oil.

[0029] By adopting the above technical solution, thyme essential oil has excellent insect repellent and antiseptic effects, and is beneficial to the preservation of finished grains after volatilization.

[0030] Optionally, the salt is a chloride or a sulfate.

[0031] In the second aspect, the present application provides a method for preparing a controlled atmosphere preservative for finished grains, adopting the following technical scheme: A method for preparing a controlled atmosphere preservative for finished grains, comprising the following steps: first stir and mix component B with iron powder, activated carbon powder and salt according to the required weight portions of the formula, then add component A, stir and mix, and then seal and store for later use.

[0032] By adopting the above technical solution, component A is added later, which is beneficial to reducing the degree of damage to the oil film during the stirring process.

[0033] In summary, this application has the following beneficial effects:

[0034] By setting up the water-releasing agent, the water release cycle is extended and the water release is delayed, so that the water will not be concentrated in a short period of time to participate in the reaction of iron powder and oxygen, thereby delaying the heat production rate. Therefore, the present application can completely reduce the oxygen content without causing excessive temperature increase, which is beneficial to the storage of finished grains. DETAILED DESCRIPTION

[0035] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0036] The examples of this application use the following raw materials:

[0037] The iron powder is reduced iron powder with a particle size of 100 mesh; the vermiculite particle size is 100 mesh.

[0038] Preparation Example 1:

[0039] The preparation process of the desiccant is as follows:

[0040] According to the ratio of 100g of vermiculite per liter of hydrochloric acid solution, the vermiculite is immersed in a hydrochloric acid solution with a hydrochloric acid concentration of 1mol / L, the temperature is raised to 70°C, and after continuous stirring for 50min, the vermiculite is removed, washed with water, dried, and finally calcined at 800°C for 30s to obtain a desiccant.

[0041] Preparation Example 2:

[0042] The preparation process of the desiccant is as follows:

[0043] According to the ratio of 100g of vermiculite per liter of hydrochloric acid solution, the vermiculite is immersed in a hydrochloric acid solution with a hydrochloric acid concentration of 1mol / L, the temperature is raised to 80°C, and after continuous stirring for 30min, it is fished out, washed with water, dried, and finally calcined at 800°C for 30s to obtain a desiccant.

[0044] Preparation Example 3:

[0045] The preparation process of the desiccant is as follows:

[0046] According to the ratio of 100g of vermiculite per liter of hydrochloric acid solution, the vermiculite is immersed in a hydrochloric acid solution with a hydrochloric acid concentration of 1mol / L, the temperature is raised to 75°C, and after continuous stirring for 40min, the vermiculite is removed, washed with water, dried, and finally calcined at 800°C for 30s to obtain a desiccant.

[0047] Preparation Example 4:

[0048] The preparation process of the modified desiccant is as follows:

[0049] The desiccant prepared in Preparation Example 3 was added to a 5wt% KH570 solution, stirred at 2000 r / min for 5 minutes, and then heated to 50°C, and kept warm for 15 minutes. Finally, the solution was filtered and dried to obtain a modified desiccant.

[0050] Preparation Example 5:

[0051] The preparation process of the modified desiccant is as follows:

[0052] The desiccant prepared in Preparation Example 3 was added to a 5 wt % KH570 solution, stirred at 2000 r / min for 10 min, heated to 60° C., and kept warm for 20 min. Finally, filtered and dried to obtain a modified desiccant.

[0053] Preparation Example 6:

[0054] The preparation process of the modified desiccant is as follows:

[0055] The desiccant prepared in Preparation Example 3 was added to a 5wt% KH570 solution, stirred at 2000 r / min for 8 minutes, heated to 55°C, and kept warm for 18 minutes. Finally, the solution was filtered and dried to obtain a modified desiccant.

[0056] Embodiment 1:

[0057] A modified atmosphere preservative for finished grains, comprising the following components:

[0058] Iron powder 40kg;

[0059] Activated carbon powder 3kg;

[0060] Sodium chloride 3kg;

[0061] 20kg water release agent.

[0062] The preparation method of the water-releasing agent is as follows:

[0063] Water absorption: Mix expanded vermiculite and water in a mass ratio of 1:1. After the expanded vermiculite completely absorbs water, separate it into 12kg of component A and 8kg of component B. Component B is reserved for later use.

[0064] Coating: Immerse component A in thyme essential oil at a ratio of 200 g component A per liter of thyme essential oil for 5 minutes, then take it out, drain off excess thyme essential oil, and seal it for later use.

[0065] It should be noted that the sum of the mass of component B and component A before coating is the added amount of the water-releasing agent.

[0066] A method for preparing a modified atmosphere preservative for finished grains comprises the following steps: firstly stirring and mixing component B with iron powder, activated carbon powder and sodium chloride according to the weight required by the formula, then adding the coated component A, stirring and mixing, and sealing and storing for later use.

[0067] Embodiment 2:

[0068] A modified atmosphere preservative for finished grains, comprising the following components:

[0069] Iron powder 60kg;

[0070] Activated carbon powder 5kg;

[0071] Sodium sulfate 5kg;

[0072] 30kg water release agent.

[0073] The preparation method of the water-releasing agent is as follows:

[0074] Water absorption: Mix expanded vermiculite and water in a mass ratio of 1:1.5. After the expanded vermiculite completely absorbs water, separate it into 24 kg of component A and 6 kg of component B, and keep component B for later use;

[0075] Coating: Immerse component A in thyme essential oil at a ratio of 200 g component A per liter of thyme essential oil for 5 minutes, then take it out, drain off excess thyme essential oil, and seal it for later use.

[0076] It should be noted that the sum of the mass of component B and component A before coating is the added amount of the water-releasing agent.

[0077] A method for preparing a modified atmosphere preservative for finished grains comprises the following steps: firstly stirring and mixing component B with iron powder, activated carbon powder and sodium sulfate according to the weight required by the formula, then adding the coated component A, stirring and mixing, and sealing and storing for later use.

[0078] Embodiment 3:

[0079] A modified atmosphere preservative for finished grains, comprising the following components:

[0080] Iron powder 50kg;

[0081] Activated carbon powder 4kg;

[0082] Sodium chloride 4kg;

[0083] 25kg water release agent.

[0084] The preparation method of the water-releasing agent is as follows:

[0085] Water absorption: Mix expanded vermiculite and water in a mass ratio of 1:1.2. After the expanded vermiculite completely absorbs water, mix them into 17.5 kg of component A and 7.5 kg of component B. Component B is reserved for later use.

[0086] Coating: Immerse component A in thyme essential oil at a ratio of 200 g component A per liter of thyme essential oil for 5 minutes, then take it out, drain off excess thyme essential oil, and seal it for later use.

[0087] It should be noted that the sum of the mass of component B and component A before coating is the added amount of the water-releasing agent.

[0088] A method for preparing a modified atmosphere preservative for finished grains comprises the following steps: firstly stirring and mixing component B with iron powder, activated carbon powder and sodium chloride according to the weight required by the formula, then adding the coated component A, stirring and mixing, and sealing and storing for later use.

[0089] Embodiment 4:

[0090] The only difference from Example 3 is that the expanded vermiculite is replaced by the moisture absorbent prepared in Preparation Example 1.

[0091] Embodiment 5:

[0092] The only difference from Example 3 is that the expanded vermiculite is replaced by the moisture absorbent prepared in Preparation Example 2.

[0093] Embodiment 6:

[0094] The only difference from Example 3 is that the expanded vermiculite is replaced by the moisture absorbent prepared in Preparation Example 3.

[0095] Embodiment 7:

[0096] The only difference from Example 3 is that the expanded vermiculite is replaced by the modified moisture absorbent prepared in Preparation Example 4.

[0097] Embodiment 8:

[0098] The only difference from Example 3 is that the expanded vermiculite is replaced by the modified moisture absorbent prepared in Preparation Example 5.

[0099] Embodiment 9:

[0100] The only difference from Example 3 is that the expanded vermiculite is replaced by the modified moisture absorbent prepared in Preparation Example 6.

[0101] Embodiment 10:

[0102] The only difference from Example 9 is that in the coating step, 17.5 kg of component A is divided into 5 parts by mass, each of which is 3.5 kg. The time for soaking the 5 parts of component A in plant essential oil is 1 min, 3 min, 5 min, 7 min, and 10 min respectively, and each is sealed and stored for later use after soaking.

[0103] When preparing the modified atmosphere preservative, when component A is needed, 5 parts of component A are added together and stirred and mixed.

[0104] Comparative Example 1:

[0105] The only difference from Example 3 is that the water-releasing agent is component B, that is, no coating step is performed.

[0106] Application examples:

[0107] Instructions for use of a modified atmosphere preservative for finished grains:

[0108] Step 1: Select a sealing film with high barrier properties and make a package suitable for holding 10kg of rice;

[0109] Step 2: Fill 10 kg of rice into the package prepared in step 1, and then add 1 package of 10 g of modified atmosphere preservative;

[0110] Step three: squeeze out excess air from the rice package and heat-seal the opening to form a sealed storage environment.

[0111] Performance testing:

[0112] Referring to the above application examples, the modified atmosphere preservatives prepared in Examples 1-3, Example 10 and Comparative Example 1 were tested. The room temperature was 25°C, the temperature inside the package was detected every 1 hour, the temperature change curve was observed, and the temperatures at 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, and 24 hours were recorded in Table 1; in addition, the oxygen content inside the package was detected every hour after 12 hours, and the time when the oxygen concentration dropped below 2% was recorded. The results are shown in Table 1.

[0113] Table 1 Performance test results of modified atmosphere preservatives for finished grains

[0114]

[0115] From the analysis of Table 1, we can get:

[0116] 1. During the use of the modified atmosphere preservative, the temperature inside the package changes parabolically. As the oxygen absorption reaction proceeds after it is put in, a large amount of heat is generated, and the temperature inside the package continues to rise. After reaching the highest temperature, as the oxygen in the package gradually decreases, the reaction temperature gradually decreases to the ambient temperature.

[0117] 2. Combining the test results of Examples 1-3 and Comparative Example 1, it can be seen that the controlled atmosphere preservative of the embodiment of the present application reaches a temperature high point close to 30°C in about 4 hours, and it takes more than 60 hours for the oxygen concentration to decrease to 2%, while the conventional controlled atmosphere preservative reaches a temperature high point close to 50°C in about 2 hours, and it takes about 23 hours for the oxygen concentration to decrease to 2%.

[0118] Combining the test results of Examples 1-3 and Comparative Example 1, it can be seen that the modified atmosphere preservatives of the embodiments of the present application control the release of water, thereby significantly reducing the reaction rate, thereby delaying the generation of heat, so that excessive heat is not generated in a short period of time. Therefore, the high point of Examples 1-3 is significantly lower than that of Comparative Example 1, and the oxygen reduction time of Examples 1-3 is longer than that of Comparative Example 1.

[0119] 3. Combining the test results of Examples 1-3, it can be seen that the temperature change curve of Example 2 is the most gentle, because the component A in the water-releasing agent accounts for a higher proportion and the reaction rate is better controlled;

[0120] 4. Combining the test results of Example 3 and Example 10, it can be seen that by modifying the expanded vermiculite and soaking component A in essential oils in batches, the reaction is further significantly delayed and the high temperature is further reduced, which has a positive significance for the stable storage of grain.

[0121] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A modified atmosphere preservative for finished grains, characterized in that: The composition comprises the following components in parts by weight: 40-60 parts of iron powder; 3-5 parts of activated carbon powder; 3-5 parts salt; 20-30 parts of water release agent; The preparation method of the water-releasing agent is as follows: Water absorption: Mix the moisture absorbent and water in a mass ratio of 1:(1-1.5), and then divide them into 60-80wt% of component A and 20-40wt% of component B, and keep component B for later use; Coating: immersing component A in plant essential oil for 1-10 minutes and then taking it out for use; in the coating step, immersing component A in plant essential oil by weight in 5 parts, and each part is immersed in the plant essential oil for 1 minute, 3 minutes, 5 minutes, 7 minutes, and 10 minutes respectively, and then taken out for use; The preparation method of the water-releasing agent further includes a modification step, and the specific process is as follows: adding the hygroscopic agent to a 5wt% KH570 solution, stirring at high speed for 5-10 minutes, heating to 50-60°C, and then keeping the temperature for 15-20 minutes, and finally filtering and drying to obtain a modified hygroscopic agent; The preparation process of the desiccant is as follows: First, immerse the vermiculite in a hydrochloric acid solution, heat it to 70-80°C, stir it continuously for 30-50 minutes, then remove it, wash it with water, dry it, and finally roast it to obtain a moisture absorbent; The plant essential oil is thyme essential oil; The salt is a chloride or a sulfate.

2. A method for preparing the modified atmosphere preservative for finished grains according to claim 1, characterized in that: The method comprises the following steps: firstly stirring and mixing component B with iron powder, activated carbon powder and salt according to the required weight parts of the formula, then adding the coated component A, stirring and mixing, and sealing and storing for later use.

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