A method of sterilizing wheat bran or wholemeal flour

Abstract

This invention relates to a sterilization method for wheat bran or whole wheat flour, belonging to the field of wheat bran processing. The method includes the following steps: sterilizing the wheat bran to be sterilized under medium-low frequency electromagnetic wave treatment to obtain sterilized wheat bran; or sterilizing the wheat bran to be sterilized under medium-low frequency electromagnetic wave treatment, pulverizing the sterilized wheat bran, and backfilling it into wheat flour to obtain sterilized whole wheat flour; the temperature of the medium-low frequency electromagnetic wave treatment is 130–190°C. This invention utilizes the energy carried by medium-low frequency electromagnetic waves to act on the wheat bran, causing friction and collision of polar molecules within the wheat bran, generating heat, thereby raising the temperature of the wheat bran to 130–190°C. Then, the high temperature is used to destroy the proteins of microorganisms and to permeate the microbial membrane, ultimately achieving the purpose of sterilizing the wheat bran and whole wheat flour. This processing method is more efficient, energy-saving, and more practical.

Description

Technical Field

[0001] This invention relates to a sterilization method for wheat bran or whole wheat flour, belonging to the field of wheat bran processing. Background Technology

[0002] Wheat bran is a byproduct of wheat flour processing, comprising approximately 22%–25% of wheat grains. Composed of the seed coat, aleurone layer, a small amount of germ, and endosperm, wheat bran is rich in soluble and insoluble non-starch polysaccharides and is known as the best source of dietary fiber in nature. However, during harvesting, threshing, drying, storage, transportation, and processing, wheat is constantly in contact with soil and other objects, causing its surface to carry various microorganisms.

[0003] Most studies indicate that wheat bran is the primary site of microbial contamination, with only a few microbial species appearing inside the grain via the germ or due to mechanical damage. Furthermore, the wheat flour production process involves conditioning with water and allowing the wheat to stand, a process that easily breeds large amounts of bacteria. The conditioning water is typically ordinary water, lacking sterilization capabilities, thus leading to an increased bacterial content in the processed wheat flour. When bran containing microorganisms is processed into whole wheat flour, it is prone to spoilage, mold growth, the production of harmful substances, and insect infestation during storage, damaging the nutritional quality of the wheat, especially during hot and humid seasons.

[0004] Currently, wheat quality is typically ensured through measures such as controlling moisture content during whole wheat flour processing, low-temperature and low-humidity storage, and controlled atmosphere storage. Another method involves eliminating microorganisms in wheat, for example, using ultrasound. However, ultrasound requires water or solid media for propagation, and because the energy of ultrasound cannot penetrate the grain, it cannot kill microorganisms inside the grain; it only promotes the vibration of microorganisms on the grain surface, thus killing them. Therefore, this method is not very effective for sterilizing wheat. Summary of the Invention

[0005] The purpose of this invention is to provide a sterilization method for wheat bran or whole wheat flour, which solves the problem of poor sterilization effect on wheat in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for sterilizing wheat bran or whole wheat flour includes the following steps: sterilizing the wheat bran to be sterilized under medium-low frequency electromagnetic wave treatment to obtain sterilized wheat bran; or sterilizing the wheat bran to be sterilized under medium-low frequency electromagnetic wave treatment, crushing the sterilized wheat bran, and backfilling it into wheat flour to obtain sterilized whole wheat flour; wherein the temperature of the medium-low frequency electromagnetic wave treatment is 130-190℃.

[0008] This invention utilizes low- to mid-frequency electromagnetic waves to carry energy and act on wheat bran, causing friction and collisions between the polar molecules inside the bran, generating heat and raising the temperature of the bran to 130–190°C. This high temperature then destroys the proteins of microorganisms and permeates the microbial membrane, ultimately sterilizing the wheat bran and whole wheat flour. This treatment method is more efficient, energy-saving, and practical.

[0009] To ensure more thorough sterilization, the treatment time using medium-low frequency electromagnetic waves is preferably 8–15 minutes. More preferably, the temperature for the medium-low frequency electromagnetic wave treatment is 170–190°C, and the treatment time is 10–15 minutes. Under these conditions, the inhibition rate of microorganisms reaches over 86%, which is superior to ultrasonic treatment.

[0010] To further improve the inactivation rate of microorganisms, preferably, the temperature of the low-frequency electromagnetic wave treatment is 170–190°C, and the time is 10–15 minutes. Under these conditions, the inhibition rate of microorganisms reaches over 90%.

[0011] To improve the sterilization effect, preferably, the frequency of the low-frequency electromagnetic wave treatment is 11-28 kHz. The present invention continuously varies the frequency within this range, causing polar molecules to constantly rub and collide, ultimately achieving a treatment temperature of 130-190°C for the low-frequency electromagnetic wave.

[0012] Preferably, the sterilization process involves killing one or more of bacteria, molds, and heat-resistant bacilli. The low-to-medium frequency electromagnetic wave treatment method of the present invention is more effective in eliminating bacteria, molds, and heat-resistant bacilli.

[0013] Preferably, the bacterial content in the wheat bran to be sterilized is not less than 10. 4.44 CFU / g. When the bacterial content in wheat bran reaches 10... 4.44 When the CFU / g is above a certain level, the inactivation rate after treatment with the low-frequency electromagnetic waves of this invention reaches more than 80%.

[0014] Preferably, the mold content in the wheat bran to be sterilized is not less than 10%. 3.52 CFU / g. When the mold content in wheat bran reaches 10... 3.52 With a CFU / g or higher, the inactivation rate after treatment with low- and medium-frequency electromagnetic waves of this invention reaches over 85%.

[0015] Preferably, the content of heat-resistant Bacillus in the wheat bran to be sterilized is not less than 10. 3.78 CFU / g. When the content of heat-resistant Bacillus in wheat bran reaches 10... 3.78 With a CFU / g or higher, the inactivation rate after treatment with low- and medium-frequency electromagnetic waves of this invention reaches more than 50%. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the sterilization process of wheat bran or whole wheat flour according to the present invention. Detailed Implementation

[0017] This invention treats wheat bran obtained after grinding wheat with low- to medium-frequency electromagnetic waves. When the low- to medium-frequency electromagnetic waves carry energy and act on the wheat bran, the polar molecules rub and collide, generating heat. Ultimately, the temperature of the wheat bran rises to 130–190°C. The high temperature can destroy the proteins of microorganisms, change the permeability of the biofilm, and inhibit the growth and survival of microorganisms, thus obtaining sterilized wheat bran.

[0018] Low- and medium-frequency electromagnetic waves, also known as high-frequency waves, are a type of electromagnetic wave. Specifically, they are electromagnetic fields formed by in-phase and mutually perpendicular electric and magnetic fields moving in space in the form of waves. They can effectively transfer energy and momentum, and their heating method is from the inside out, resulting in higher heating efficiency than traditional heating methods. They have advantages such as fast heating speed, high efficiency, environmental friendliness, energy saving, and strong penetrating power.

[0019] This invention first performs a series of pretreatments on wheat, such as cleaning raw wheat, moistening wheat, and cleaning smooth wheat. Then, wheat bran and flour (i.e., wheat flour) are obtained through milling. The obtained wheat bran is transported by conveyor belt through a medium- and low-frequency electromagnetic wave treatment area for medium- and low-frequency electromagnetic wave treatment. After treatment, the wheat bran is crushed and mixed back into the flour to obtain whole wheat flour. The specific flow chart is shown below. Figure 1 As shown.

[0020] The wheat used in Examples 1-6 and Comparative Example 1 was from the same batch, and the bacterial colony count in the untreated wheat bran was 10. 4.44 The CFU / g level was approximately 10, and the total mold count was 10. 3.52 Approximately CFU / g, with a total number of thermoresistant spores of 10. 3.78 Approximately CFU / g.

[0021] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0022] I. Specific embodiments of the sterilization method for wheat bran or whole wheat flour of the present invention are as follows:

[0023] Example 1

[0024] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0025] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0026] (2) Set the temperature of the low-frequency electromagnetic wave generator to 130℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 10 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran rises to 130℃. When it reaches 130℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0027] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0028] Example 2

[0029] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0030] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0031] (2) Set the temperature of the low-frequency electromagnetic wave generator to 170℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 10 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran rises to 170℃. When it reaches 170℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0032] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0033] Example 3

[0034] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0035] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0036] (2) Set the temperature of the low-frequency electromagnetic wave generator to 190℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 10 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran reaches 190℃. When it reaches 190℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0037] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0038] Example 4

[0039] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0040] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0041] (2) Set the temperature of the low-frequency electromagnetic wave generator to 170℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 8 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran rises to 170℃. When it reaches 170℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0042] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0043] Example 5

[0044] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0045] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0046] (2) Set the temperature of the low-frequency electromagnetic wave generator to 170℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 12 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran rises to 170℃. When it reaches 170℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0047] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0048] Example 6

[0049] The sterilization method for whole wheat flour in this embodiment adopts the following steps:

[0050] (1) Wheat with excessive bacterial colony count, mold count or heat-resistant spore count is treated and wheat bran and flour are obtained through wheat milling process. The obtained wheat bran is transported by conveyor belt through the medium and low frequency electromagnetic wave treatment area.

[0051] (2) Set the temperature of the low-frequency electromagnetic wave generator to 170℃ and control the speed of the conveyor belt so that the time for the wheat bran to pass through the low-frequency electromagnetic wave treatment area is 15 minutes. The low-frequency electromagnetic wave generator automatically adjusts its working frequency according to the set temperature. The working frequency is 11~28KHz. When the wheat bran is treated, the polar molecules rub and collide to generate heat, so that the temperature of the wheat bran rises to 170℃. When it reaches 170℃, the low-frequency electromagnetic wave generator will use frequency conversion to keep the temperature constant.

[0052] (3) Crush the wheat bran after it has been treated with low-frequency electromagnetic waves and backfill it into the flour so that the wheat bran and wheat flour are mixed evenly to obtain whole wheat flour.

[0053] II. Comparative Example

[0054] Comparative Example 1

[0055] The sterilization method for whole wheat flour in this comparative example adopts the following steps:

[0056] (1) Wheat bran and flour obtained by wheat milling process, and ultrasonic treatment of the obtained wheat bran;

[0057] (2) Set the ultrasonic frequency to 20kHz, the power to 400W, and the processing time to 15min;

[0058] (3) Crush the ultrasonically treated wheat bran and backfill it into the flour to mix the wheat bran and wheat flour evenly to obtain whole wheat flour.

[0059] Ultrasonic waves and low-frequency electromagnetic waves are different processes. Ultrasonic waves are mechanical waves generated by the vibration of objects, while low-frequency electromagnetic waves are electromagnetic waves generated by the vibration of electric charges. Ultrasonic waves require water or solids as a medium to propagate and cannot propagate in a vacuum, while low-frequency electromagnetic waves can propagate in a vacuum. Ultrasonic waves can promote the vibration of microorganisms on the surface of grains and kill them, but the energy is not transferred to the inside of the grains, so it does not have a significant impact on the quality of the grain endosperm. The low-frequency electromagnetic waves used in this invention kill microorganisms mainly by using the high temperature generated by the low-frequency electromagnetic waves and the vibration of the low-frequency electromagnetic waves to fully kill microorganisms attached to the surface, those tightly bound to the cortex, and those that have invaded the surface.

[0060] III. Experimental Examples

[0061] This experiment measured the sterilization rate of wheat bran treated with low-frequency electromagnetic waves in Examples 1-6 and wheat bran treated with ultrasound in Comparative Example 1. The results are shown in Tables 1-3.

[0062] The test methods are as follows: Total bacterial count: according to GB 4789.2-2016 "Food Microbiology Examination - Determination of Total Colony Count". Total mold count: according to GB 4789.15-2016 "Food Microbiology Examination - Counting of Molds and Yeasts". Total thermostable Bacillus count: The sample was diluted according to GB 4789.2-2016 "Food Microbiology Examination - Determination of Total Colony Count", and 10-fold serial dilutions were prepared. The test tubes were then incubated in a water bath at 80℃ for 15 minutes. After cooling, 2-3 samples of suitable dilutions were homogenized. 1 mL of the homogenate was transferred to a sterile Petri dish, and nutrient agar medium was poured in. The mixture was incubated at 36℃ for 48 hours before counting.

[0063] Table 1 shows the effect of low-frequency electromagnetic wave treatment on the bacterial inactivation rate of wheat bran.

[0064] Comparison -- -- 4.44±0.02 0 Example 1 130 10 3.68±0.05 82.39±2.02 Example 2 170 10 3.22±0.02 93.86±0.27 Example 3 190 10 1.63±0.15 99.84±0.05 Example 4 170 8 3.52±0.04 87.98±1.19 Example 5 170 12 3.06±0.12 95.66±1.17 Example 6 170 15 2.80±0.16 97.55±0.85 Comparative Example 1 -- -- 3.59±0.10 85.72

[0065] As shown in Table 1, the total bacterial count of the control group without treatment with low-to-medium frequency electromagnetic waves was lg(CFU / g) = 4.44, which is equivalent to a colony count of 10-1. 4.44 In Examples 1-6, the CFU / g of low-frequency electromagnetic wave treatment resulted in a bacterial inactivation rate of over 80% in wheat bran, significantly reducing the number of bacteria in wheat bran and whole wheat flour, demonstrating a good sterilization effect. This sterilization effect was comparable to that of ultrasonic treatment in Comparative Example 1. When the temperature of the low-frequency electromagnetic wave treatment was increased to 170-190℃, the bacterial inactivation rate was higher than that of ultrasonic treatment. When the temperature of the low-frequency electromagnetic wave treatment was 170-190℃ and the time was 10-15 minutes, the bacterial inactivation rate reached over 90%, indicating an even better sterilization effect.

[0066] Table 2 shows the effect of low-frequency electromagnetic wave treatment on the inactivation rate of mold in wheat bran.

[0067] Comparison -- -- 3.52±0.07 0 Example 1 130 10 2.63±0.04 87.22±1.06 Example 2 170 10 <1 100 Example 3 190 10 <1 100 Example 4 170 8 <1 100 Example 5 170 12 <1 100 Example 6 170 15 <1 100 Comparative Example 1 -- -- 2.61±0.06 87.76

[0068] As shown in Table 2, the total number of mold colonies in the control group without treatment with low-to-medium frequency electromagnetic waves was lg(CFU / g) = 3.52, which is equivalent to a colony count of 10. 3.52 In Examples 1-6, the CFU / g of wheat bran treated with low-to-medium frequency electromagnetic waves resulted in a mold inactivation rate of over 85%, significantly reducing the amount of mold in wheat bran and whole wheat flour, demonstrating a good sterilization effect. This sterilization effect was comparable to that of ultrasonic treatment in Comparative Example 1. When the temperature of the low-to-medium frequency electromagnetic wave treatment was increased to 170-190℃, the mold inactivation rate was higher than that of ultrasonic treatment. When the temperature of the low-to-medium frequency electromagnetic wave treatment was 170-190℃ and the time was 10-15 minutes, the mold inactivation rate reached 100%, resulting in an even better sterilization effect.

[0069] Table 3 shows the effect of low-frequency electromagnetic wave treatment on the inactivation rate of thermostable Bacillus in wheat bran.

[0070] Comparison -- -- 3.78±0.03 0 Example 1 130 10 3.46±0.04 51.67±0.84 Example 2 170 10 2.54±0.18 93.71±2.46 Example 3 190 10 1.15±0.15 99.75±0.08 Example 4 170 8 2.92±0.02 86.25±0.42 Example 5 170 12 2.19±0.01 97.42±0.09 Example 6 170 15 2.01±0.01 98.29±0.04 Comparative Example 1 3.42±0.08 56.17

[0071] Table 3 shows that the total number of thermostable Bacillus strains in the control group, which was not treated with low-frequency electromagnetic waves, was lg(CFU / g) = 3.78, which is equivalent to a colony count of 102. 3.78 In Examples 1-6, the use of low-frequency electromagnetic wave treatment resulted in an inactivation rate of over 50% for thermoresistant Bacillus in wheat bran, significantly reducing the number of thermoresistant Bacillus in wheat bran and whole wheat flour, demonstrating a good sterilization effect. This sterilization effect was comparable to that of ultrasonic treatment in Comparative Example 1. When the temperature of the low-frequency electromagnetic wave treatment was increased to 170-190℃, the inactivation rate for thermoresistant Bacillus was higher than that of ultrasonic treatment. When the temperature of the low-frequency electromagnetic wave treatment was 170-190℃ and the time was 10-15 min, the inactivation rate for thermoresistant Bacillus reached over 90%, indicating an even better sterilization effect. Furthermore, according to the comparison in Tables 1-3, the low-frequency electromagnetic wave treatment of this invention has the best sterilization effect on mold.

Claims

1. A method for sterilizing wheat bran or whole wheat flour, characterized in that, Includes the following steps: The wheat bran to be sterilized is sterilized under medium- and low-frequency electromagnetic wave treatment to obtain sterilized wheat bran; or the sterilized wheat bran is crushed and backfilled into wheat flour to obtain sterilized whole wheat flour; the temperature of the medium- and low-frequency electromagnetic wave treatment is 170~190 ℃; the frequency of the medium- and low-frequency electromagnetic wave treatment is 11~28 KHz; the sterilization under the medium- and low-frequency electromagnetic wave treatment involves transporting the wheat bran through the medium- and low-frequency electromagnetic wave treatment area by a conveyor belt.

2. The sterilization method for wheat bran or whole wheat flour according to claim 1, characterized in that, The processing time for the medium and low frequency electromagnetic waves is 8 to 15 minutes.

3. The sterilization method for wheat bran or whole wheat flour according to claim 2, characterized in that, The processing time for the medium and low frequency electromagnetic waves is 10 to 15 minutes.

4. The sterilization method for wheat bran or whole wheat flour according to any one of claims 1-3, characterized in that, The sterilization process involves killing one or both of the following: bacteria and mold.

5. The sterilization method for wheat bran or whole wheat flour according to any one of claims 1-3, characterized in that, The sterilization process involves killing heat-resistant spore-forming bacteria.

6. The sterilization method for wheat bran or whole wheat flour according to claim 1, characterized in that, The wheat bran to be sterilized contains no less than 10 bacteria. 4.44 CFU / g.

7. The sterilization method for wheat bran or whole wheat flour according to claim 1, characterized in that, The mold content in the wheat bran to be sterilized is not less than 10%. 3.52 CFU / g.

8. The sterilization method for wheat bran or whole wheat flour according to claim 1, characterized in that, The heat-resistant Bacillus content in the wheat bran to be sterilized is not less than 10%. 3.78 CFU / g.

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