Microwave uniform sterilization system as well as use method and application thereof

Abstract

The invention discloses a microwave sterilization system as well as a use method and application thereof. The microwave sterilization system comprises an air compressor, an oil-water separator, a micro-regulating valve, a gas flowmeter, a ventilation pipeline, a needle head filter, a temperature sensor, a reactor, a rotating platform and microwave equipment, the air compressor, the oil-water separator and the reactor are sequentially communicated through a ventilation pipeline; a micro regulating valve and a gas flow meter are arranged between the oil-water separator and the reactor; the micro-regulating valve is arranged at the front end of the gas flow meter; a temperature sensor is arranged in the reactor; adding a to-be-treated material into the reactor, starting the microwave equipment, and rotating the rotating platform; then the air compressor is started, and the gas flow meter is adjusted through the micro-adjusting valve; and finally, microwave power and heating temperature are adjusted, and microwave and ventilation operations are simultaneously performed on the materials. Through the synergistic effect of double mechanisms of physical rotation and bubble disturbance, the uniformity of a microwave thermal field is remarkably improved, the sterilization effect is ensured, and the quality of materials is kept to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a microwave uniform sterilization system and its usage and application. Background Technology

[0002] Microwave sterilization technology, with its outstanding advantages such as rapid heating, energy efficiency, and ease of control, has become a promising high-quality processing technology in the food industry. This technology utilizes the dipole rotation and frictional heating mechanism of polar molecules in a high-frequency electromagnetic field to achieve a "volume heating" effect on the material from the inside out. Compared to traditional heat sterilization methods, the most significant feature of microwave processing is its extremely fast heating rate. This not only significantly shortens sterilization time and improves processing efficiency but also effectively avoids the degradation and loss of heat-sensitive components during prolonged heat treatment, thus better preserving the natural color, flavor, and nutrients of food.

[0003] However, the transition of microwave sterilization technology from laboratory research to large-scale industrial application still faces the critical challenge of uneven heating. Currently, continuous flow microwave sterilization is commonly used in industry, improving heat distribution uniformity through material flow. However, for high-viscosity foods such as jams and sesame pastes, their poor flowability makes it difficult to achieve uniform flow using pumping methods, thus rendering such dynamic sterilization processes unsuitable. Under static processing conditions, the lack of forced convection within the material means that effective thermal mixing cannot be achieved solely through natural convection, resulting in a vertical temperature gradient that is higher at the top and lower at the bottom. This macroscopic non-uniformity, combined with the microscopic hot and cold spot distribution within the microwave cavity caused by the electromagnetic standing wave effect, further exacerbates the temperature field non-uniformity, severely limiting the advantages of rapid microwave heating. This not only easily leads to microbial residue in cold spots but may also cause overheating and product deterioration in hot spots. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, this invention provides a microwave uniform sterilization system, its usage method, and its applications. This invention enhances fluid flow and improves the uniformity of the microwave heating thermal field through the synergistic effect of rotation and bubbling, enabling its application in food systems of varying viscosities.

[0005] The technical solution of the present invention is as follows: The first objective of this invention is to provide a microwave uniform sterilization system, comprising an air compressor, an oil-water separator, a micro-regulating valve, a gas flow meter, an air duct, a needle filter, a temperature sensor, a reactor, and a microwave device; The air compressor, oil-water separator and reactor are connected in sequence through a ventilation pipe, which is equipped with a needle filter. A micro-regulating valve and a gas flow meter are installed between the oil-water separator and the reactor; the micro-regulating valve is located at the front end of the gas flow meter. The reactor is equipped with a temperature sensor to monitor the temperature of the reaction system.

[0006] In one embodiment of the invention, the reactor is a 15 mL glass test tube, which is mounted on a rotating platform connected to the center of the bottom of a microwave device.

[0007] In one embodiment of the present invention, the ventilation pipe is a PU pipe, and the pipe is connected to a needle filter.

[0008] In one embodiment of the invention, the end of the ventilation pipe is located at the bottom of the reactor.

[0009] In one embodiment of the present invention, a rotating platform is provided at the center of the bottom of the microwave device, located at the bottom of the reactor; the rotating platform can achieve central rotation.

[0010] A second objective of this invention is to provide a method of using the above-mentioned microwave uniform sterilization system, comprising the following steps: (1) Add the material to be processed into the reactor, turn on the microwave equipment, and make the rotating platform rotate; (2) Turn on the air compressor and adjust the gas flow meter to a flow rate of 1~180 mL / min through the micro-adjustment valve; (3) Adjust the microwave power and heating temperature of the microwave equipment to achieve microwave and ventilation operation on the material at the same time.

[0011] In one embodiment of the present invention, in step (1), the rotational speed is 450 r / min.

[0012] In one embodiment of the present invention, in step (2), the microwave power is 300 W and the heating temperature is raised to 90°C in 40 s.

[0013] In one embodiment of the present invention, for a system with a viscosity of 1~10 mPa·s, represented by milk, the gas flow rate input is 40~180 mL / min.

[0014] In one embodiment of the present invention, for a system with a viscosity of 300~600 mPa·s, represented by blueberry jam, the gas flow rate input is 60~160 mL / min.

[0015] In one embodiment of the present invention, for a system with a viscosity of 600~1000 mPa·s, represented by sesame paste, the gas flow rate input is 70~140 mL / min.

[0016] The third objective of this invention is to provide an application of the above-mentioned microwave uniform sterilization system for food processing to extend the shelf life of food.

[0017] The beneficial technical effects of this invention are as follows: This invention significantly improves the uniformity of the microwave thermal field through the synergistic effect of physical rotation and bubble disturbance, ensuring sterilization effect and maintaining the quality of materials to the greatest extent.

[0018] This invention combines rotation and bubbling, introducing both macroscopic shear force and microscopic disturbance, to achieve comprehensive mixing of fluid from the whole to the local, fundamentally breaking the uneven distribution of the microwave field and greatly improving the uniformity of the thermal field.

[0019] This invention provides more thorough sterilization, effectively solving the problem of sterilization blind spots caused by uneven heating and ensuring food safety; at the same time, it avoids local overheating and better preserves the nutritional components, color, flavor and other quality attributes of the materials.

[0020] This invention has broad applicability; by adjusting parameters (rotation speed, bubble flow rate), it can cover a range of 1~1000 mPa. Foods with a viscosity range of s.

[0021] The process of this invention is controllable. By precisely controlling the rotation speed, bubbling gas volume and heating program, the entire process is standardized and repeatable, which is conducive to industrial application. Attached Figure Description

[0022] Figure 1 The diagram shows the microwave uniform sterilization system of the present invention: 1. Air compressor, 2. Oil-water separator, 3. Micro-regulating valve, 4. Gas flow meter, 5. Ventilation pipe, 6. Needle filter, 7. Temperature sensor, 8. Reactor, 9. Rotary platform, 10. Microwave equipment.

[0023] Figure 2 The temperature curves are for heat conduction treatment and microwave slow treatment.

[0024] Figure 3 The effect of different rotation speeds under microwave treatment on the number of surviving Escherichia coli in CMC with a viscosity of 1 mPa·s.

[0025] Figure 4 The bacterial count of milk treated using the methods provided in Example 1 and Comparative Examples 1-5 was measured within 14 days of storage at 4°C.

[0026] Figure 5 The alkaline phosphatase content of milk after treatment using the methods provided in Example 1 and Comparative Examples 1-5 is determined.

[0027] Figure 6 The pH of milk treated using the methods provided in Example 1 and Comparative Examples 1-5 was determined after storage at 4°C for 14 days.

[0028] Figure 7 Titratable acidity of milk treated using the methods provided in Example 1 and Comparative Examples 1-5, respectively, after being stored at 4°C for 14 days.

[0029] Figure 8 The bacterial count of blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10 was measured within 30 days of storage at 25°C.

[0030] Figure 9 The antioxidant capacity of blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10 is evaluated.

[0031] Figure 10 Titratable acidity of blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10, respectively, after being stored at 25°C for 30 days.

[0032] Figure 11 The bacterial count of sesame paste treated using the methods provided in Example 7 and Comparative Examples 11-15 was measured within 30 days of storage at 25°C.

[0033] Figure 12 The acid value of sesame paste treated using the methods provided in Example 7 and Comparative Examples 11-15 was determined after storage at 25°C for 30 days. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Titratable acid: measures the total amount of all acidic components in food, and is mainly used in fruits, juices, beverages, etc.

[0036] Acid value: measures the content of free fatty acids in oils and fats, and is specifically used for oils and oily foods.

[0037] like Figure 1 As shown, a microwave uniform sterilization system includes an air compressor 1, an oil-water separator 2, a micro-regulating valve 3, a gas flow meter 4, an air duct 5, a needle filter 6, a temperature sensor 7, a reactor 8, a rotating platform 9, and a microwave device 10.

[0038] Air compressor 1, oil-water separator 2 and reactor 8 are connected in sequence through air pipe 5; A micro-regulating valve 3 and a gas flow meter 4 are provided between the oil-water separator 2 and the reactor 8; the micro-regulating valve 3 is located at the front end of the gas flow meter 4. The reactor 8 is equipped with a temperature sensor 7 to monitor the temperature of the reaction system.

[0039] Ventilation pipe 5 is a PU pipe. The end of ventilation pipe 5 is located at the bottom of reactor 8.

[0040] The microwave device 10 is equipped with a rotating platform 9, which is located at the bottom of the reactor 8.

[0041] A method of using the microwave uniform sterilization system includes the following steps: (1) Add the material to be processed into the reactor, turn on the microwave equipment, and make the rotating platform rotate; (2) Turn on the air compressor and adjust the gas flow meter to a flow rate of 1-180 mL / min using the micro-adjustment valve; (3) Adjust the microwave power and heating temperature of the microwave equipment to achieve microwave and ventilation operation on the material at the same time.

[0042] Bubbles should be introduced from the center of the bottom of the material. A comparison of the bactericidal effects of heat conduction and conventional microwave heating (without rotation or bubbling) on ​​E. coli confirmed that microwave heating exhibits significant microscopic inhomogeneity.

[0043] Step 1: Optimization of Parameter Coordinated Control a. A temperature sensor is used to plot the microwave heating curve, and the microwave power program is adjusted to achieve a high degree of fit with the preset heat conduction sterilization temperature-time curve, such as... Figure 2 As shown.

[0044] b. Test different rotational speeds (0, 150, 250, 350, 450, 550 rpm) without bubbling air. For example... Figure 3 As shown, when the rotation speed reaches 450 rpm, the number of surviving E. coli bacteria drops to the lowest level, indicating the best thermal uniformity. Therefore, the optimal rotation speed is determined to be 450 rpm.

[0045] c. With the optimal rotational speed fixed at 450 rpm, the effect of sterile air bubbling volume on systems of different viscosities was tested. As the system viscosity increased, the air volume threshold corresponding to the significant decrease in goodness of fit gradually decreased. Specifically, at a viscosity of 1 mPa·s, the goodness of fit decreased significantly after the air volume exceeded 180 mL / min; at viscosities of 300 mPa·s and 600 mPa·s, the goodness of fit decreased significantly after the air volume exceeded 160 mL / min; and when the viscosity increased to 1000 mPa·s, the goodness of fit decreased significantly after the air volume exceeded 140 mL / min. Based on the analysis and optimization of the above experimental data, the optimal operating parameter range for systems with different viscosities was determined: Viscosity 1~10 mPa·s: rotation speed 450 r / min, bubble flow rate 40~180 mL / min; Viscosity 10~300 mPa·s: rotation speed 450 r / min, bubble flow rate 60~160 mL / min; Viscosity 300~600 mPa·s: rotation speed 450 r / min, bubble flow rate 60~160 mL / min; Viscosity 600~1000 mPa·s: rotation speed 450 r / min, bubble flow rate 70~140 mL / min; Viscosity 1000~1200 mPa·s: rotation speed 450 r / min, bubble flow rate 60 mL / min, temperature rise 20℃ to final temperature 90℃; Viscosity 1200~1500 mPa·s: rotation speed 450 r / min, bubble flow rate 40 mL / min, temperature rise 25℃ to final temperature 95℃.

[0046] Example 1: A microwave treatment method for extending the shelf life of milk includes the following steps: (1) Raw material pretreatment: Take 50 L of raw milk with a viscosity of 2 mPa·s (initial microbial indicators: total bacterial count of 4.85 log CFU / mL, Salmonella of 3.09 log CFU / mL, Escherichia coli of 4.39 log CFU / mL, Staphylococcus aureus of 3.27 log CFU / mL), dispense it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing chamber and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was introduced into the milk through the bottom aeration device, and the gas flow rate was controlled to 40 mL / min; the microwave processing adopted a rapid heating program with a microwave power of 300 W, so that the milk temperature rose from the initial temperature to 90℃ within 40 s; (3) Microwave sterilization treatment: The rotating and bubbling system is started simultaneously and microwave treatment is applied. During the treatment, the milk forms a uniform vortex state under the disturbance of rotation and bubbles. Example 2: A microwave treatment method for extending the shelf life of milk includes the following steps: (1) Raw material pretreatment: Same as in Example 1; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing chamber and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was introduced into the milk through the bottom aeration device, and the gas flow rate was controlled to 110 mL / min; the microwave processing adopted a rapid heating program with a microwave power of 300 W, so that the milk temperature rose from the initial temperature to 90℃ within 40 s; (3) Microwave sterilization treatment: The rotating and bubbling system is started simultaneously and microwave treatment is applied. During the treatment, the milk forms a uniform vortex state under the disturbance of rotation and bubbles. Example 3: A microwave treatment method for extending the shelf life of milk includes the following steps: (1) Raw material pretreatment: Same as in Example 1; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing chamber and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was introduced into the milk through the bottom aeration device, and the gas flow rate was controlled to 180 mL / min; the microwave processing adopted a rapid heating program with a microwave power of 300 W, so that the milk temperature rose from the initial temperature to 90℃ within 40 s; (3) Microwave sterilization treatment: The rotating and bubbling system is started simultaneously and microwave treatment is applied. During the treatment, the milk forms a uniform vortex state under the disturbance of rotation and bubbles. Comparative Example 1 A method for preserving cow's milk, comprising the following steps: Take 50 L of raw milk from the same batch, without any processing.

[0047] Comparative Example 2 A method for sterilizing cow's milk includes the following steps: (1) Raw material pretreatment: Take 50 L of raw milk from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Milk heat conduction sterilization: 72℃ water bath is used for conduction heating.

[0048] Comparative Example 3 A method for microwave sterilization of milk includes the following steps: (1) Raw material pretreatment: Take 50 L of raw milk from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the rotation and bubbling system, microwave treatment is directly used. The microwave power is 300 W, which raises the milk temperature from the initial temperature to 90°C within 40 seconds.

[0049] Comparative Example 4 A method for microwave sterilization of milk includes the following steps: (1) Raw material pretreatment: Take 50 L of raw milk from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the bubbling system, microwave treatment is used at a horizontal rotation speed of 450 r / min and a microwave power of 300 W, so that the milk temperature rises from the initial temperature to 90℃ within 40 s.

[0050] Comparative Example 5 A method for microwave sterilization of milk includes the following steps: (1) Raw material pretreatment: Take 50 L of raw milk from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Microwave treatment is used without turning on the rotation, only when the bubble input is 180 mL / min, and the microwave power is 300 W, so that the milk temperature rises from the initial temperature to 90℃ within 40 s.

[0051] Example 4 A microwave treatment method for extending the shelf life of blueberry jam includes the following steps: (1) Raw material pretreatment: Take 25 kg of blueberry jam with a viscosity of 500 mPa·s. The initial microbial index is a total colony count of 3.11 log CFU / g; the quality index includes color L value of 22.13, a value of 3.45, b value of -6.74, titratable acid content of 0.85%, and DPPH free radical scavenging rate of 65.67%. Dispense the jam into 15 mL high-temperature resistant quartz sample tubes, with each tube containing 1 mL; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 60 mL / min; the microwave power was 300 W, so that the blueberry jam could be heated from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the jam is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0052] Example 5 A microwave treatment method for extending the shelf life of blueberry jam includes the following steps: (1) Raw material pretreatment: Same as in Example 5; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 110 mL / min; the microwave power was 300 W, so that the blueberry jam could be heated from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the jam is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0053] Example 6 A microwave treatment method for extending the shelf life of blueberry jam includes the following steps: (1) Raw material pretreatment: Same as in Example 5; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 160 mL / min; the microwave power was 300 W, so that the blueberry jam could be heated from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the jam is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0054] Comparative Example 6 A method for preserving blueberry jam, comprising the following steps: Take 25 kg of blueberry jam from the same batch, without any processing.

[0055] Comparative Example 7 A method for sterilizing blueberry jam includes the following steps: (1) Raw material pretreatment: Take 25 kg of blueberry jam from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Sterilization of blueberry jam by heat conduction: a 72℃ water bath is used for conduction heating.

[0056] Comparative Example 8 A method for microwave sterilization of blueberry jam includes the following steps: (1) Raw material pretreatment: Take 25 kg of blueberry jam from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the rotation and bubbling system, microwave treatment is directly used. The microwave power is 300 W, so that the blueberry jam can be heated from the initial temperature to 90°C within 40 seconds.

[0057] Comparative Example 9 A method for microwave sterilization of blueberry jam includes the following steps: (1) Raw material pretreatment: Take 25 kg of blueberry jam from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the bubbling system, microwave treatment is carried out at a horizontal rotation speed of 450 r / min and a microwave power of 300 W, so that the blueberry jam can be heated from the initial temperature to 90℃ within 40 s.

[0058] Comparative Example 10 A method for microwave sterilization of blueberry jam includes the following steps: (1) Raw material pretreatment: Take 25 kg of blueberry jam from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: without turning on the rotation, microwave treatment is used only when the bubble input is 160 mL / min, and the microwave power is 300 W, so that the blueberry jam rises from the initial temperature to 90℃ within 40 s.

[0059] Example 7 A microwave treatment method for extending the shelf life of sesame paste includes the following steps: (1) Raw material pretreatment: Take 25 kg of sesame paste with a viscosity of 900 mPa·s and an initial microbial index of 4.16 log CFU / g total bacterial count; quality indicators include L value of 63.95, a value of 4.25, b value of 18.11, and acid value of 1.16. Dispense the sesame paste into 15 mL high-temperature resistant quartz sample tubes, with each tube containing 1 mL; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 70 mL / min; the microwave power was 300 W, so that the sesame paste temperature rose from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the sesame paste is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0060] Example 8 A microwave treatment method for extending the shelf life of sesame paste includes the following steps: (1) Raw material pretreatment: Same as in Example 7; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 105 mL / min; the microwave power was 300 W, so that the sesame paste temperature rose from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the sesame paste is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0061] Example 9 A microwave treatment method for extending the shelf life of sesame paste includes the following steps: (1) Raw material pretreatment: Same as in Example 7; (2) Construction and parameter setting of homogenization system: The sample was placed in the microwave processing cavity and the platform rotation speed was set to 450 r / min; the air compressor was turned on and sterile air was continuously introduced through the bottom microporous aeration device, and the gas flow rate was controlled to 140 mL / min; the microwave power was 300 W, so that the sesame paste temperature rose from the initial temperature to 90℃ within 40 s. (3) Microwave sterilization: The rotation and bubbling system are started simultaneously, and microwaves are applied. During the process, the sesame paste is fully mixed and heated evenly under the synergistic effect of mechanical rotation and bubble disturbance.

[0062] Comparative Example 11 A method for preserving sesame paste, comprising the following steps: Take 25 kg of sesame paste from the same batch, without any processing.

[0063] Comparative Example 12 A method for sterilizing sesame paste includes the following steps: (1) Raw material pretreatment: Take 25 kg of sesame paste from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Heat conduction sterilization of sesame paste: a 72℃ water bath is used for conduction heating.

[0064] Comparative Example 13 A method for microwave sterilization of sesame paste includes the following steps: (1) Raw material pretreatment: Take 25 kg of sesame paste from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the rotation and bubbling system, microwave treatment is directly used. The microwave power is 300 W, so that the sesame paste temperature rises from the initial temperature to 90℃ within 40 s.

[0065] Comparative Example 14 A method for microwave sterilization of sesame paste includes the following steps: (1) Raw material pretreatment: Take 25 kg of sesame paste from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: Without turning on the bubbling system, microwave treatment is carried out at a horizontal rotation speed of 450 r / min and a microwave power of 300 W, so that the sesame paste can be heated from the initial temperature to 90℃ within 40 s.

[0066] Comparative Example 15 A method for microwave sterilization of sesame paste includes the following steps: (1) Raw material pretreatment: Take 25 kg of sesame paste from the same batch and divide it into 15 mL quartz tubes, with each tube containing 1 mL; (2) Microwave sterilization: without turning on the rotation, microwave treatment is used only when the bubble input is 140 mL / min, and the microwave power is 300 W, so that the sesame paste rises from the initial temperature to 90℃ within 40 s.

[0067] Test case 1. Samples from Example 1 and Comparative Examples 1-5 were processed and immediately sampled to detect the total bacterial count and alkaline phosphatase activity. The samples were then stored at 4°C for 14 days, and quality indicators such as pH and titratable acid content were measured.

[0068] in conclusion: Figure 4 The figure shows the changes in bacterial count of milk treated with the methods provided in Example 1 and Comparative Examples 1-5 after storage at 4°C for 14 days. As can be seen from the figure, the total bacterial count of the sample treated in Example 1 was significantly lower than that of the comparative examples, and the bacterial count increased the slowest during storage. This indicates that the microwave homogenization method can effectively sterilize milk, significantly inhibit microbial growth, and thus effectively extend the shelf life of milk. Figure 5 The alkaline phosphatase activity of milk treated with the methods provided in Example 1 and Comparative Examples 1-5 was measured. The results showed that the alkaline phosphatase activity of the sample from Example 1 was the lowest, with virtually no residual activity, indicating that the method was thorough in sterilization. However, the comparative examples still showed varying degrees of residual enzyme activity, indicating that their sterilization effect was incomplete. Figure 6 The pH values ​​of milk treated using the methods provided in Example 1 and Comparative Examples 1-5 were measured after storage at 4°C for 14 days. The results showed that the pH of the sample from Example 1 remained stable with minimal variation; while the pH of the comparative samples decreased significantly, indicating that acidification occurred during storage, which is related to active microbial metabolism. Figure 7 The titratable acid content of milk treated using the methods provided in Example 1 and Comparative Examples 1-5 was measured after storage at 4°C for 14 days. The results show that the acidity increase in the sample of Example 1 was minimal, maintaining the original physicochemical properties of the milk; while the acidity of the comparative examples increased significantly, indicating varying degrees of quality deterioration during storage. Table 1 shows the color of the milk treated using the methods provided in Example 1 and Comparative Examples 1-5, demonstrating that Example 1 effectively maintains the original color of the milk.

[0069] Table 1

[0070] 2. For Examples 4 and Comparative Examples 6-10, the total bacterial count, color, titratable acid content, and antioxidant capacity of each sample were immediately tested after treatment. The remaining samples were stored at 25°C in the dark, and the above indicators were tested after 30 days.

[0071] in conclusion: Figure 8The figure shows the changes in bacterial count in blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10, respectively, after storage at 25°C for 30 days. As can be seen from the figure, the total bacterial count in the sample of Example 4 was significantly lower than that in the comparative examples, and the bacterial growth was the slowest, indicating that the microwave homogenization method can also effectively kill microorganisms in blueberry jam and significantly extend the product's shelf life. Figure 9 The antioxidant capacity of blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10 is measured. Figure 9 The antioxidant capacity of blueberry jam treated with the methods provided in Example 4 and Comparative Examples 6-10 was measured. The results showed that the sterilization techniques used in Example 4 and Comparative Examples 7-10 both had a certain impact on the antioxidant capacity of the blueberry jam. Compared with Comparative Example 6, which was not heat-treated, the microwave homogenization treatment in Example 4 had the best effect on maintaining antioxidant activity, which was better than that in Comparative Examples 7-10. Figure 10 The titratable acidity of blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10 was measured after 30 days of storage at 25°C. The results showed that the acidity of Comparative Examples 6 and 8-10 decreased significantly, indicating varying degrees of quality deterioration during storage. However, the acidity of the samples from Example 4 and Comparative Example 7 did not change significantly, indicating that the microwave homogenization rapid sterilization of Example 4 and the conventional heat conduction sterilization of Comparative Example 7 did not differ significantly in acidity retention. Table 2 shows the color of the blueberry jam treated using the methods provided in Example 4 and Comparative Examples 6-10, demonstrating that Example 4 effectively maintained the original color of the blueberry jam.

[0072] Table 2

[0073] 3. Examples 7 and Comparative Examples 11-15: Samples were taken immediately after treatment and microbial indicators (total colony count) were tested. The samples were stored at 25°C in the dark and the quality indicators of sesame paste (color and acid value) were measured at the end of the 30-day storage period.

[0074] in conclusion: Figure 11 The changes in bacterial count of sesame paste treated using the methods provided in Example 7 and Comparative Examples 11-15 were observed during storage at 25°C for 30 days. The results showed that the total bacterial count in the sample of Example 7 was significantly lower than that in the comparative examples, and the bacterial growth was the slowest, indicating that microwave homogenization can also effectively sterilize sesame paste and reduce microbial growth. Figure 12The acid value of sesame paste treated using the methods provided in Example 7 and Comparative Examples 11-15 was measured after 30 days of storage at 25°C. The results showed that conventional heat treatment and various microwave treatments had little impact on the acid value of sesame paste after 30 days of storage, indicating that the fat oxidation of this type of product is relatively stable during storage. Table 3 shows the color of the sesame paste treated using the methods provided in Example 7 and Comparative Examples 11-15, demonstrating that Example 7 effectively maintained the original color of the sesame paste.

[0075] Table 3

[0076] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A microwave uniform sterilization system, characterized in that, Includes an air compressor (1), an oil-water separator (2), a micro-regulating valve (3), a gas flow meter (4), a ventilation pipe (5), a needle filter (6), a temperature sensor (7), a reactor (8), a rotating platform (9), and a microwave device (10). The air compressor (1), oil-water separator (2) and reactor (8) are connected in sequence through the air pipe (5); A micro-regulating valve (3) and a gas flow meter (4) are provided between the oil-water separator (2) and the reactor (8); the micro-regulating valve (3) is located at the front end of the gas flow meter (4); The reactor (8) is equipped with a temperature sensor (7) to monitor the temperature of the reaction system.

2. The microwave uniform sterilization system according to claim 1, characterized in that, The ventilation duct (5) is a PU tube, and the duct is connected to a needle filter (6).

3. The microwave uniform sterilization system according to claim 1, characterized in that, The end of the ventilation pipe (5) is placed at the bottom of the reactor (8).

4. The microwave uniform sterilization system according to claim 1, characterized in that, The microwave device (10) is equipped with a rotating platform (9) located at the bottom of the reactor (8).

5. A method of using the microwave sterilization uniformity system according to claim 1, characterized in that, Includes the following steps: (1) Add the material to be processed into the reactor, turn on the microwave equipment, and make the rotating platform rotate; (2) Turn on the air compressor and adjust the gas flow meter to a flow rate of 1~180 mL / min through the micro-adjustment valve; (3) Adjust the microwave power and heating temperature of the microwave equipment to achieve microwave and ventilation operation on the material at the same time.

6. The method of use according to claim 5, characterized in that, In step (1), the rotational speed is 450 r / min.

7. The method of use according to claim 5, characterized in that, In step (2), the microwave power is 300 W and the heating temperature is raised to 90℃ in 40 s.

8. An application of the microwave uniform sterilization system according to claim 1, characterized in that, Used in food processing to extend the shelf life of food products.

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