Method for treating agricultural materials based on double-frequency microwaves

Abstract

The invention discloses a method for treating agricultural materials based on double-frequency microwaves, and belongs to the technical field of agricultural material processing. The method provided by the invention comprises the following steps: the agricultural materials are processed by alternately transmitting microwaves at a 2450MHz main frequency and a 915MHz auxiliary frequency, the transmission time ratio of the main frequency to the auxiliary frequency is (4-1): (1-2), and the total irradiation time of the double-frequency alternate transmission is 45-60 seconds. According to the invention, the main frequency and auxiliary frequency alternate emission is adopted to improve the material sterilization rate, the oriented degradation of macromolecules is ensured, the heat-sensitive nutrition retention rate is improved, the problems of large nutrition loss and low treatment efficiency in the traditional process are solved, and the method is suitable for efficient modification of feeds, grains and the like. The agricultural materials are processed by adopting the dual-frequency microwave method for alternately transmitting the main frequency and the auxiliary frequency, the method is more efficient and low in cost, the quality of the materials can be guaranteed, and technical support is provided for processing of the agricultural materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural material processing, and particularly relates to a method for processing agricultural materials based on dual-frequency microwaves. Background Art

[0002] Links such as the modification of livestock and poultry feed, the pre-treatment of grain storage, and the preparation of functional raw materials play a key role in ensuring agricultural production efficiency and the quality of agricultural products.

[0003] During the microwave treatment process, due to the lack of precise temperature and time control means, it is easy to damage the quality of the materials. When modifying livestock and poultry feed, excessive microwaves may destroy the nutrients in the feed, reduce the nutritional value of the feed, and thus affect the growth and development of livestock and poultry; when preparing functional raw materials, improper microwave treatment will change the chemical structure of the raw materials, resulting in the loss of functional components or a decrease in activity, and failing to meet the product quality requirements. At the same time, the method is time-consuming and laborious, requires a high preparation cost, and has an unsatisfactory sterilization effect, which is not conducive to long-term storage in the later stage. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for processing agricultural materials based on dual-frequency microwaves. This method can shorten the sterilization treatment time of agricultural materials, improve the sterilization rate of agricultural materials, increase the retention rate of thermosensitive nutrients and the effective rate of lysine in agricultural materials, reduce the starch molecular weight and the average length of peptide chains in agricultural materials. The method is simple, and the operating cost of the processed agricultural materials is low.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for processing agricultural materials based on dual-frequency microwaves. The method includes the following steps: alternately emitting microwaves with a main frequency of 2450 MHz and a secondary frequency of 915 MHz to process agricultural materials. The emission time ratio of the main frequency and the secondary frequency is (4 - 1):(1 - 2), and the total irradiation time of the dual-frequency alternate emission is 45 - 60 seconds.

[0007] Preferably, the temperature of the microwave treatment is 70 - 90 °C.

[0008] Preferably, the power of the microwave treatment is 5 - 10 kW.

[0009] Preferably, the initial moisture content of the agricultural materials is 12% - 18%.

[0010] Preferably, 0.1% - 0.3% by mass of magnesium carbonate is mixed and added to the agricultural materials before microwave treatment.

[0011] Preferably, vacuum pulse cooling is carried out after microwave treatment, and the degree of vacuum for the vacuum pulse cooling is ≤ 50 Pa; the agricultural materials include corn, soybeans and sorghum.

[0012] The present invention also provides agricultural materials obtained by treating with the above method.

[0013] The present invention also provides the application of the above method in shortening the sterilization time of agricultural materials.

[0014] The present invention also provides the application of the above method in increasing the sterilization rate of agricultural materials.

[0015] The present invention also provides the application of the above method in at least one of S1 to S4,

[0016] S1. Increasing the retention rate of heat-sensitive nutrients in agricultural materials,

[0017] S2. Reducing the starch molecular weight of agricultural materials,

[0018] S3. Increasing the efficiency of lysine in agricultural materials,

[0019] S4. Reducing the average length of peptide chains in agricultural materials.

[0020] Preferably, the heat-sensitive nutrient is vitamin B1.

[0021] Advantages of the present invention:

[0022] Based on the method for treating agricultural materials by dual-frequency microwave, the present invention can shorten the sterilization time of agricultural materials, increase the sterilization rate of agricultural materials, increase the retention rate of heat-sensitive nutrients and the efficiency of lysine in agricultural materials, reduce the starch molecular weight and the average length of peptide chains of agricultural materials. The method is simple, and the operating cost of the treated agricultural materials is low. It solves the problems of large nutrient loss and low treatment efficiency in traditional processes, and is applicable to the high-efficiency modification of agricultural materials such as feed and grain. Detailed implementation manners

[0023] The present invention provides a method for treating agricultural materials based on dual-frequency microwave, and the method includes the following steps: the agricultural materials are alternately emitted with a main frequency of 2450 MHz and a secondary frequency of 915 MHz. In the present invention, the emission time ratio of the main frequency to the secondary frequency is (4 - 1):(1 - 2), and more preferably 4:1; the total irradiation time of the dual-frequency alternate emission is 45 - 60 seconds, and more preferably 45 seconds.

[0024] As an alternative embodiment, the initial moisture content of the agricultural material is 14%. The temperature of the microwave treatment is preferably 70°C to 90°C, more preferably 80°C; the power of the microwave treatment is preferably 5 to 10 kW, more preferably 7.5 kW. Before the microwave treatment, 0.1% to 0.3% by mass of magnesium carbonate is mixed and added to the agricultural material, more preferably 0.2%. The addition of the magnesium carbonate is to improve the microwave absorption efficiency. After the microwave treatment, vacuum pulse cooling is carried out, and the degree of vacuum of the vacuum pulse cooling is ≤50 Pa. Preferably, the agricultural material after the microwave treatment is cooled to 25°C at a cooling rate of 50°C / s under a vacuum condition of 30 Pa. The agricultural material includes corn, soybean, and sorghum, preferably corn.

[0025] The present invention adopts a method for treating corn based on dual-frequency microwaves, and the sterilization rate of the material is increased by 99.9%. In the present invention, the 2450 MHz microwave targets and cuts the β-1,4 glycosidic bond, decomposing cellulose into soluble oligosaccharides and monosaccharides. The 915 MHz microwave destroys the protein disulfide bond, and can achieve a 30% to 50% directional degradation of macromolecules and a thermosensitive nutrient retention rate >95%. In addition, the treatment time of the method of the present invention is short, only 45 to 60 seconds, saving costs.

[0026] The present invention also provides the agricultural material obtained by treating with the method. The agricultural material includes corn, soybean, and sorghum, preferably corn. The retention rate of vitamin B1 in the corn of the present invention can reach 98.7%, the starch molecular weight is reduced to 5.1×10 5 Da, the lysine efficiency is 88.5%, and the average length of the peptide chain is 86±2 AA. The retention rate of vitamin B1 in the treated modified agricultural material is higher, and the protein is more easily digested and absorbed by animals.

[0027] The present invention also provides the application of the method in shortening the sterilization time of agricultural materials. The agricultural materials of the present invention include corn, soybean, and sorghum, preferably corn. The actual sterilization time of the present invention only needs 45 to 60 seconds.

[0028] The present invention also provides the application of the method in improving the sterilization rate of agricultural materials. The actual sterilization efficiency of the present invention can reach 99.99%.

[0029] The present invention also provides the application of the method in any one or more of the following,

[0030] S1. Improving the retention rate of thermosensitive nutrients in agricultural materials,

[0031] S2. Reducing the starch molecular weight of agricultural materials,

[0032] S3. Improving the lysine efficiency of agricultural materials,

[0033] S4. Reduce the average length of the peptide chain of agricultural materials.

[0034] Preferably, the thermosensitive nutrient is vitamin B1.

[0035] As an alternative embodiment, after treating corn by the method, the retention rate of vitamin B1 in the corn can reach 98.7%, the starch molecular weight is reduced to 5.1×10 5 Da, the effective rate of lysine is 88.5%, and the average length of the peptide chain is 86±2 AA.

[0036] In the present invention, there are no special limitations on the sources of the corn and magnesium carbonate, and they can be prepared or obtained by conventional methods according to actual needs.

[0037] In the present invention, there are also no special limitations on the microwave equipment, and it can be conventionally selected and set according to actual needs.

[0038] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0039] In the following embodiments, unless otherwise specified, all are conventional methods.

[0040] In the following embodiments, the materials and reagents used, unless otherwise specified, can all be obtained from commercial channels.

[0041] Example 1

[0042] A method for treating corn based on dual-frequency microwave, the method steps are as follows:

[0043] (1) Prepare 10 kg of corn with an initial moisture content of 14%. After removing impurities, add 0.1-0.3% of magnesium carbonate based on the mass of the corn and mix evenly to obtain premixed corn.

[0044] (2) Subject the above premixed corn to dual-frequency alternating emission of a main frequency of 2450 MHz and a sub-frequency of 915 MHz, with a temperature of 80°C and a microwave power of 7.5 W. The emission time ratio of the main frequency and the sub-frequency is preferably 4:1, and the total irradiation time is 45 seconds.

[0045] (3) Vacuum pulse cooling: Under a vacuum condition of 30 Pa, cool down to 25°C at a cooling rate of 50°C / s to obtain the treated corn.

[0046] Comparative Example 1

[0047] Treat 10 kg of corn with an initial moisture content of 14% by the traditional microwave method, with a microwave operating frequency of 2450 MHz, a power of 7.5 kW, a temperature of 60°C, a time of 120 min, and cool at room temperature to obtain the treated corn.

[0048] Test Example 1

[0049] Taking corn with an initial moisture content of 14% without any treatment as the blank control, the treated corn prepared in Example 1 and Comparative Example 1 respectively was used to measure the following indexes.

[0050] 1. Determination of total mold count

[0051] The determination of the total mold count under different treatments was carried out according to the detection method used for the determination of the total mold count in feed in GB / T 13092-2006, and the detection results are shown in Table 1.

[0052] Table 1 Total mold count of different treatments

[0053]

[0054] As can be seen from Table 1, the sterilization rate of the corn treated by the method described in Example 1 of the present invention is increased to 99.9% compared with the blank control.

[0055] 2. Detection of heat-sensitive nutrient - vitamin B1

[0056] The detection of vitamin B1 was carried out by fluorescence spectrophotometry (GB 5009.84-2016), and the results are shown in Table 2.

[0057] Table 2 Detection results of vitamin B in corn after different treatments 1 Content detection results

[0058]

[0059] According to the data recorded in Table 2, it can be known that the retention rate of vitamin B1 in the corn treated by the method described in Example 1 can reach 98.7%, which is significantly higher than 85% of Comparative Example 1.

[0060] 3. Determination of available lysine

[0061] The determination of available lysine was carried out with reference to the method of GB / T 18868-2002, and the determination results are shown in Table 3.

[0062] Table 3 Detection results of available lysine in corn under different treatments

[0063]

[0064] As shown in Table 3, the available lysine rate in the corn treated by the method of Example 1 is significantly higher than that of Comparative Example 1 and the blank control, indicating that the lysine that can be absorbed and utilized by animals in the corn increases.

[0065] 4. Determination of starch molecular weight

[0066] (1) The molecular weight of starch was determined by gel permeation chromatography (reference: Huang Lixin, Gao Qunyu, Yang Yigong. Study on the molecular weight distribution of starches from different varieties [J]. Journal of South China University of Technology (Natural Science Edition), 1997, (07): 31 - 35.), and the results are shown in Table 4.

[0067] Table 4 Detection results of starch molecular weight under different treatments

[0068]

[0069] The results in Table 4 show that compared with the blank control, the molecular weight of corn starch in Example 1 decreased significantly, and the directional degradation rate of macromolecules reached 49%.

[0070] 5. Detection of average peptide chain length

[0071] The average peptide chain length is approximately the ratio of the total nitrogen content measured by the GB6432 - 9 method to the α - nitrogen content measured by the formaldehyde titration method, and the reference is Guo Yudong, Zhang Yang, Zhang Junguo. Nutritional value and evaluation method of small peptide feed. Feed Industry, 2007, 28(7): 13 - 16.

[0072] The detection results of the average peptide chain length are shown in Table 5:

[0073] Table 5 Detection results of average peptide chain length

[0074]

[0075] By comparing Example 1 with the blank control and Comparative Example 1, it was found that the average peptide chain length of the corn treated with Example 1 decreased significantly, indicating that the protein in the corn treated with Example 1 is more easily digested and absorbed by animals.

[0076] Example 2

[0077] A method for treating corn based on dual - frequency microwave, the steps of the method are as follows:

[0078] (1) Prepare 10 kg of corn with an initial moisture content of 12%. After removing impurities, add 0.3% of magnesium carbonate based on the mass of the corn and mix evenly to obtain the premixed corn.

[0079] (2) The above - mentioned premixed corn is irradiated with dual - frequency alternating emission of 2450 MHz main frequency and 915 MHz sub - frequency, the temperature is 70 °C, the microwave power is 10 kW, and the emission time ratio of the main frequency and the sub - frequency is preferably 4:1, and the total irradiation time is 50 seconds.

[0080] (3) Vacuum pulse cooling: Under a vacuum condition of 40 Pa, cool down to 25 °C at a cooling rate of 50 °C / s to obtain the treated corn.

[0081] The sterilization rate, retention rate of heat-sensitive nutrient - vitamin B1, lysine availability, starch molecular weight, retention rate of heat-sensitive nutrients, and average peptide chain length of the corn treated in this example were detected respectively according to the methods of determination of total mold count, detection of heat-sensitive nutrient - vitamin B1, determination of available lysine, determination of starch molecular weight, and detection of average peptide chain length described in Test Example 1.

[0082] Results: The sterilization rate of the corn treated by the method described in Example 2 increased by 99.9%, the starch molecular weight decreased by 30% - 50%, the retention rate of heat-sensitive nutrients was greater than 95%, the lysine availability was greater than 85%, and the average peptide chain length decreased by more than 40%.

[0083] Example 3

[0084] A method for treating corn based on dual-frequency microwave, the steps of the method are as follows:

[0085] (1) Prepare 10 kg of corn with an initial moisture content of 18%. After removing impurities, add 0.1% of magnesium carbonate based on the mass of the corn and mix evenly to obtain the premixed corn.

[0086] (2) The above premixed corn is irradiated with dual frequencies of 2450 MHz main frequency and 915 MHz auxiliary frequency alternately, the temperature is 90 °C, the microwave power is 5 kW, the emission time ratio of the main frequency and the auxiliary frequency is preferably 4:1, and the total irradiation time is 60 seconds.

[0087] (3) Vacuum pulse cooling: Under a vacuum condition of 50 Pa, cool down to 25 °C at a cooling rate of 50 °C / s to obtain the treated corn.

[0088] The sterilization rate, retention rate of heat-sensitive nutrient - vitamin B1, lysine availability, starch molecular weight, retention rate of heat-sensitive nutrients, and average peptide chain length of the corn treated in this example were detected respectively according to the methods of determination of total mold count, detection of heat-sensitive nutrient - vitamin B1, determination of available lysine, determination of starch molecular weight, and detection of average peptide chain length described in Test Example 1.

[0089] Results: The sterilization rate of the corn treated by the method described in Example 3 increased by 99.9%, the starch molecular weight decreased by 30% - 50%, the retention rate of heat-sensitive nutrients was greater than 95%, the lysine availability was greater than 85%, and the average peptide chain length decreased by more than 40%.

[0090] In summary, using the method for treating corn based on dual-frequency microwave of the present invention, the sterilization rate of the corn treated by the method increased by 99.9%, the starch molecular weight decreased by 30% - 50%, the retention rate of heat-sensitive nutrients was greater than 95%, the lysine availability was greater than 85%, and the average peptide chain length decreased by more than 40%.

[0091] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for treating agricultural materials based on dual-frequency microwaves, characterized in that: The method comprises the following steps: using 2450MHz main frequency and 915MHz auxiliary frequency to alternately transmit microwaves to treat agricultural materials, the emission time ratio of the main frequency and the auxiliary frequency is (4-1):(1-2), and the total irradiation time of the dual-frequency alternating emission is 45-60 seconds.

2. The method according to claim 1, characterized in that: The temperature of the microwave treatment is 70-90°C.

3. The method according to claim 1, characterized in that: The power of the microwave treatment is 5-10 kW.

4. The method according to claim 1, characterized in that: The initial moisture content of the agricultural material is 12% to 18%.

5. The method according to claim 1, characterized in that: 0.1% to 0.3% by weight of magnesium carbonate is mixed and added to the agricultural materials before microwave treatment.

6. The method according to claim 1, characterized in that: After the microwave treatment, vacuum pulse cooling is performed, and the vacuum degree of the vacuum pulse cooling is ≤50Pa; the agricultural materials include corn, soybeans and sorghum.

7. The agricultural material obtained by the method according to any one of claims 1 to 6.

8. Use of the method according to any one of claims 1 to 6 in shortening the sterilization time of agricultural materials.

9. Use of the method according to any one of claims 1 to 6 for improving the sterilization rate of agricultural materials.

10. Use of the method according to any one of claims 1 to 6 in at least one of S1 to S4, S1. Improve the retention rate of heat-sensitive nutrients in agricultural materials, S2. Reduce the molecular weight of starch in agricultural materials, S3. Improve the lysine efficiency of agricultural materials, S4. Reduce the average peptide chain length of agricultural materials.

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