System and method for reducing bacteria and keeping fresh of fresh and wet rice noodles

Abstract

The invention discloses a bacteria-reducing and fresh-keeping system and method for fresh and wet rice noodles. The system comprises an atmospheric pressure dielectric barrier discharge low-temperature plasma generator, an upper electrode and an upper dielectric plate of the atmospheric pressure dielectric barrier discharge low-temperature plasma generator are stably installed above fresh wet rice noodle washing equipment through a support, and the vertical positions of the upper electrode and the upper dielectric plate can be adjusted. According to the equipment, air is used as working gas, a uniform and stable plasma area is formed in the rice noodle washing process, and active water is generated, so that the rice noodles are effectively sterilized and kept fresh. And the intelligent control system realizes start-stop control of the plasma generator, discharge parameter adjustment and linkage control of the operation rhythm of the powder washing equipment, and ensures that the sterilization treatment and the production process are synchronously carried out. The system is compact in structure and easy and convenient to operate. According to the method for reducing bacteria and preserving fresh and wet rice noodles through the system, online non-thermal bacteria reducing treatment can be conducted on the fresh and wet rice noodles, meanwhile, loosening and quality maintaining of the rice noodles are achieved, the preservation period of the rice noodles is remarkably prolonged, and the system has wide industrial application prospects.

Description

Technical Field

[0001] The invention relates to the field of rice product preservation, and in particular to a system and method for sterilization preservation of fresh wet rice noodles. Background Art

[0002] Rice noodles are a traditional staple food second only to cooked rice in southern my country and Southeast Asia. High-moisture fresh wet rice noodles, particularly those produced through extrusion and cold-water washing, are popular among consumers for their smooth and chewy texture. However, the shelf life of fresh wet rice noodles is typically only 1-2 days, and even less than 16 hours in hot weather. This leads to rapid quality degradation, significantly limiting their shelf life and transportation range, and increasing food safety risks. Currently, traditional preservation methods primarily include heat sterilization, pickling, and the addition of chemical preservatives such as propylene glycol. However, these methods not only compromise the quality, flavor, and taste of rice noodles but also pose potential safety risks. Furthermore, these methods offer limited preservation effectiveness and lack broad-spectrum efficacy. Invention patent ZL200810030644.X discloses "a preservative for fresh wet rice noodles". This preservative is a chemical preservative composed of sodium dehydroacetate and stabilized chlorine dioxide, and needs to be prepared with sterile water, further increasing the production process; while the "a method for preparing fresh rice noodles" disclosed in patent application 201710376277.8 still uses the method of adding preservatives and combines it with a heat sterilization method that may have a potential impact on the quality of rice noodles.

[0003] Low-temperature plasma technology is a novel, efficient, and clean non-thermal sterilization method. It utilizes various gases as carrier gases to generate active species such as electrons, atoms, ions, and free radicals, effectively killing microorganisms. This technology leaves no known chemical residues and, due to its non-thermal nature, has minimal impact on food quality. Therefore, it has attracted considerable attention in the field of food preservation. In her master's thesis, "Effects of Dielectric Barrier Discharge (DBD) Plasma Treatment on the Storage Quality of Fresh Wet Rice Noodles," Gao Wanxin investigated the application of DBD plasma as a non-thermal sterilization technology for preserving fresh wet rice noodles. This method involves preparing fresh wet rice noodles, placing them in a controlled atmosphere box filled with different gases, and sealing them. The method then uses DBD plasma, without any water washing. This method combines DBD plasma with modified atmosphere packaging for sterilization and preservation. However, because this method involves separate, discrete operations for preparing and preserving the fresh wet rice noodles, the process is cumbersome and difficult to integrate directly into an industrial continuous production line. Furthermore, the noodles can increase their hardness and decrease their elasticity.

[0004] Currently, no research has reported integrating low-temperature plasma technology with fresh wet rice noodle production lines to reduce bacteria and preserve rice noodles. Therefore, integrating low-temperature plasma technology with fresh wet rice noodle production lines to develop an online system and method for reducing bacteria and preserving rice noodles could be a significant breakthrough in extending the shelf life of high-moisture rice noodles, a staple food. Summary of the Invention

[0005] In view of the problems that fresh wet rice noodles have a short shelf life and are difficult to keep fresh, as well as the shortcomings and deficiencies in the existing technology, the purpose of the present invention is to provide a system and method for reducing bacteria and preserving fresh wet rice noodles, which is a breakthrough in the preservation of industrialized fresh wet rice noodles and solves the bottleneck problem in the existing technology.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A system for reducing bacteria and preserving fresh wet rice noodles, comprising:

[0008] Powder washing equipment 1;

[0009] The plasma device includes an atmospheric pressure dielectric barrier discharge low-temperature plasma generator, a high-voltage power supply 6, and a bracket 7; the atmospheric pressure dielectric barrier discharge low-temperature plasma generator includes an upper electrode 2, an upper dielectric plate 3, a lower electrode 4, and a lower dielectric plate 5;

[0010] Intelligent control device 10;

[0011] The bracket 7 is fixed on the powder washing equipment 1, and an upper electrode 2 is provided on the bracket 7, an upper dielectric plate 3 is provided below the upper electrode 2, a lower dielectric plate 5 is provided on the outer bottom of the powder washing equipment 1, and a lower electrode 4 is provided below the lower dielectric plate 5; the intelligent control device 10 is electrically connected to the powder washing equipment 1, the high-voltage power supply 6, the bracket 7, and the atmospheric pressure dielectric barrier discharge low-temperature plasma generator respectively.

[0012] Preferably, the rice noodle washing equipment is provided with a conveyor belt for conveying fresh wet rice noodles; a plasma generating space for sterilizing and preserving fresh wet rice noodles is formed between the upper electrode and the lower electrode, so that the conveyor belt portion of the rice noodle washing equipment is located in the plasma generating space.

[0013] Preferably, the upper electrode and the upper dielectric plate are integrally packaged and installed above the rice noodle washing device; the lower electrode is jointly packaged with a lower dielectric plate and placed on the outer bottom of the rice noodle washing device, and the lower dielectric plate is located between the lower electrode and the bottom of the rice noodle washing device, serving as an insulating blocking medium for the electric field to prevent electrical breakdown and improve discharge uniformity; the plasma in the plasma device excites the water molecules in the rice noodle washing device to undergo ionization reaction through the action of the electric field between the upper and lower electrodes, and the generated active particles are in full contact with the microorganisms on the surface of the rice noodles and in the water body, thereby achieving efficient sterilization and preservation effects.

[0014] Preferably, the upper dielectric plate is placed between the upper electrode and the water body in the powder washing equipment, serving as a dielectric barrier material during the action of the electric field, for preventing the high-voltage electric field from directly contacting the water flow, while improving the discharge uniformity and safety; the material of the upper dielectric plate is selected from materials with high insulation, heat resistance and moisture resistance, such as glass, quartz, ceramic or polytetrafluoroethylene; the lower dielectric plate is placed between the lower electrode and the bottom of the powder washing equipment, and is packaged as a whole with the lower electrode, for achieving insulation barrier of the lower electrode, preventing breakdown discharge, and improving the stability of the discharge process; the material of the lower dielectric plate is selected from materials with strong moisture resistance, high dielectric strength and good structural stability, such as ceramic, mica board, polytetrafluoroethylene, epoxy resin composite board, etc.

[0015] Preferably, the bracket is used to firmly install the upper electrode and upper dielectric plate of the plasma generator and position them above the powder washing equipment; insulating rods 8 are provided at both ends of the bracket, the insulating rods are connected to the powder washing equipment, and the vertical distance between the upper electrode and the water body in the powder washing equipment is adjusted by an electric lifting device or a driving device, thereby optimizing the plasma action area and treatment effect.

[0016] Preferably, the plasma equipment further comprises a box 9, the atmospheric pressure dielectric barrier discharge low-temperature plasma generator and the bracket are placed inside the box, and the high-voltage power supply is placed on the box chassis; the box is made of stainless steel and has good structural strength, corrosion resistance and waterproof properties; a shielding door is provided on the front of the box, and an observation window made of organic glass or polycarbonate material is provided on the shielding door for monitoring the plasma discharge state; the inner wall of the box is covered with a polytetrafluoroethylene or ceramic insulation layer for improving electrical insulation and safety during the discharge process; a vent is provided on the box, and the vent is equipped with a safety grille and a filter to ensure air circulation and prevent external particles from entering the equipment.

[0017] Preferably, the intelligent control device is integrated and installed on the side shell of the powder washing equipment, including a programmable logic controller (PLC) system and a touch-screen LCD connected to it for controlling the atmospheric pressure dielectric barrier discharge low-temperature plasma generator, the high-voltage power supply, the fresh wet rice noodle conveyor belt in the powder washing equipment, and the plasma upper electrode lifting control device; the PLC system is also used to monitor the operating parameters of the plasma system in real time, and adjust the output voltage and frequency of the high-voltage power supply according to changes in the water conductivity, temperature, water volume and rice noodle load in the powder washing equipment to adapt to different operating loads and ensure the stability of plasma discharge and the consistency of the sterilization effect; at the same time, the PLC system can be connected to the host computer terminal of the production line equipment to realize real-time monitoring of the production process.

[0018] Preferably, the fresh wet rice noodles are fresh wet round rice noodles.

[0019] A method for reducing bacteria and preserving fresh wet rice noodles comprises the following steps:

[0020] (1) in the production process of fresh wet rice flour, rice enters the powder washing link after the operations such as fermentation, decomposition, steaming sheet, extruding silk, boiling in water successively, in this stage, fresh wet rice flour enters the system of above-mentioned fresh wet rice flour sterilization and fresh-keeping, when fresh wet rice flour is washed by powder washing equipment, synchronously open plasma equipment, set treatment parameter;

[0021] (2) Fresh wet rice noodles pass through the washing equipment and enter the next production link.

[0022] Preferably, the parameters of the system for reducing bacteria and preserving fresh wet rice noodles are set as follows: the gas source is atmosphere (air), the voltage is 30-160 kV, the discharge gap is 10-90 mm, the discharge time interval is 10-30 s, and the discharge time is 1-5 min.

[0023] Further preferably, the parameters in the system for reducing bacteria and preserving fresh wet rice noodles are set as follows: the gas source is atmosphere (air), the voltage is 60-120 kV, the discharge gap is 30-60 mm, the discharge time interval is 10-30 s, and the discharge time is 5 min.

[0024] Preferably, the fresh wet rice noodles are fresh wet round rice noodles.

[0025] The method for reducing bacteria and preserving fresh wet rice noodles of the present invention can achieve continuous reducing bacteria and preserving freshness while cooling and shaping the sticky rice noodles, enhancing their elasticity, and removing surface starch during the production process of fresh wet round rice noodles. The method can extend the shelf life of the fresh wet round rice noodles by more than 6 to 12 times without affecting the appearance, texture, taste and other qualities of the fresh wet round rice noodles.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) The fresh wet rice noodle sterilization and fresh-keeping system of the present invention realizes industrialized online continuous sterilization and fresh-keeping of fresh wet round rice noodles by installing a plasma generator on the original powder washing equipment, using atmospheric pressure air without any cost as a carrier gas, utilizing the active particles generated by the plasma, the generated mobile active water and the appropriate reduction of the pH value of the mobile water, and reducing the use of traditional chemical preservatives.

[0028] (2) The system and method of the present invention can simultaneously achieve cooling and shaping of sticky rice noodles, enhance elasticity, remove surface starch, and achieve online continuous sterilization and preservation during the production process of fresh wet rice noodles, thereby extending the shelf life.

[0029] (3) The present invention uses plasma technology to reduce bacteria and preserve freshness, which is green, environmentally friendly, safe and harmless. The active particles generated by the plasma disappear in a short time, and mainly act through the intermediate state, avoiding residues. Compared with traditional chemical preservatives, the treatment method of the present invention is safer and non-toxic, eliminating the health risks that may be caused by chemical substances; compared with traditional pasteurization methods, plasma technology can better maintain the texture, flavor, taste and nutritional components of rice noodles, and avoid the damage to the quality of rice noodles caused by high temperature.

[0030] (4) The plasma production line equipment of the present invention is compatible with existing powder washing equipment, enabling seamless integration and low modification costs, making it suitable for large-scale industrial production. Furthermore, the intelligent control system can monitor and adjust the plasma output in real time, ensuring equipment stability and treatment effectiveness, meeting the high requirements for treatment accuracy and efficiency in large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of the main structure of the fresh wet round rice noodle sterilization and preservation system of the present invention.

[0032] Figure 2 This is an appearance diagram of the fresh wet round rice noodles obtained in Examples 2-3 of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail with reference to the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] like Figure 1 As shown, a system for reducing bacteria and preserving fresh wet rice noodles in this embodiment includes a rice noodle washing device 1, an upper electrode 2 of a dielectric barrier discharge low-temperature plasma generator, an upper dielectric plate 3, a lower electrode 4, a lower dielectric plate 5, a high-voltage power supply 6, a bracket 7, an insulating rod 8, a housing 9, and an intelligent control device 10. The upper electrode and upper dielectric plate of the low-temperature plasma generator are integrally packaged and mounted above the rice noodle washing device. The lower electrode is positioned at the outer bottom of the washing device and co-packaged with a lower dielectric plate, which is located between the lower electrode and the bottom of the washing device. The bracket is used to securely mount the upper electrode and upper dielectric plate of the plasma generator and position them above the washing device. Insulating rods are provided at both ends of the bracket and are connected to the washing device. The housing is the external structural component of the plasma generator. The front of the housing is provided with a shielding door with an observation window made of organic glass or polycarbonate material. A ventilation port is provided at the top of the housing. The high-voltage power supply is placed on the housing chassis. The intelligent control system is integrated and mounted on the side housing of the washing device.

[0036] Example 2

[0037] A system for reducing bacteria and preserving fresh wet rice noodles according to Example 1 of the present invention is used. The method for reducing bacteria and preserving fresh wet round rice noodles is as follows: the fresh wet round rice noodles need to undergo a cold water washing process during the preparation process. When the rice noodles pass through the washing equipment, plasma is turned on, the gas is atmospheric (air), the processing voltage is 60kV, the discharge gap is 60mm, the discharge time interval is 10s, and the total rice noodle processing time is 5min. The plasma treatment has no effect on the appearance, texture and mouthfeel of the fresh wet round rice noodles. The fresh wet rice noodles of the control and plasma treatment groups are as follows: Figure 2 As shown in the figure, after being placed at room temperature of 25℃ for a certain period of time, the rice noodles in the control group have obviously changed color and become sticky, while the rice noodles in the plasma-treated group have no significant difference from the initial sample, and the quality remains good, and the shelf life is extended by 8 times.

[0038] Example 3

[0039] A system for reducing bacteria and preserving fresh wet rice noodles using embodiment 1 of the present invention is used. The method for reducing bacteria and preserving fresh wet round rice noodles is as follows: the fresh wet round rice noodles need to undergo a cold water washing process during the preparation process. When the rice noodles pass through the washing equipment, plasma is turned on, the gas is atmospheric (air), the processing voltage is 120kV, the discharge gap is 30mm, the discharge time interval is 30s, and the total processing time of the rice noodles is 5min. The plasma treatment does not affect the appearance, texture and mouthfeel of the fresh wet round rice noodles. The rice noodles in the control group after being placed at 25°C for a certain period of time have obviously changed color and become sticky, while the rice noodles in the plasma-treated group have no significant difference from the initial sample, and the quality remains good, and the shelf life is extended by 11 times.

[0040] Comparative Example 1

[0041] Fresh, wet round rice noodles were placed in packaging and treated with a dielectric barrier discharge plasma. The gas was atmospheric air, the treatment voltage was 60 kV, the discharge gap was 60 mm, the discharge interval was 10 seconds, and the total treatment time was 5 minutes. Plasma treatment increased the hardness of the fresh, wet round rice noodles and reduced their elasticity. When stored at 25°C, the shelf life of the noodles was extended by six times.

[0042] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A system for reducing bacteria and preserving fresh wet rice noodles, characterized in that: include: Powder washing equipment (1); A plasma device comprises an atmospheric pressure dielectric barrier discharge low-temperature plasma generator, a high-voltage power supply (6), and a bracket (7); the atmospheric pressure dielectric barrier discharge low-temperature plasma generator comprises an upper electrode (2), an upper dielectric plate (3), a lower electrode (4), and a lower dielectric plate (5); Intelligent control device (10); The bracket (7) is fixed on the powder washing device (1); an upper electrode (2) is provided on the bracket (7); an upper dielectric plate (3) is provided below the upper electrode (2); a lower dielectric plate (5) is provided on the outer bottom of the powder washing device (1); and a lower electrode (4) is provided below the lower dielectric plate (5); and the intelligent control device (10) is electrically connected to the powder washing device (1), the high-voltage power supply (6), the bracket (7), and the atmospheric pressure dielectric barrier discharge low-temperature plasma generator, respectively.

2. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The rice noodle washing equipment is provided with a conveyor belt for conveying fresh wet rice noodles; a plasma generating space for sterilizing and preserving fresh wet rice noodles is formed between the upper electrode and the lower electrode, so that the conveyor belt part of the rice noodle washing equipment is located in the plasma generating space.

3. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The upper electrode and the upper dielectric plate are integrally packaged and installed above the rice noodle washing device; the lower electrode and a lower dielectric plate are co-packaged and placed on the outer bottom of the rice noodle washing device. The lower dielectric plate is located between the lower electrode and the bottom of the rice noodle washing device and serves as an insulating barrier medium for the electric field to prevent electrical breakdown and improve discharge uniformity. The plasma in the plasma device excites water molecules in the rice noodle washing device to produce an ionization reaction through the electric field between the upper and lower electrodes. The generated active particles fully contact the microorganisms on the surface of the rice noodles and in the water, achieving efficient sterilization and preservation effects.

4. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The upper dielectric plate is placed between the upper electrode and the water body in the powder washing equipment, serving as a dielectric barrier material during the electric field action process, and is used to prevent the high-voltage electric field from directly contacting the water flow, while improving the discharge uniformity and safety; the material of the upper dielectric plate is selected from materials with high insulation, heat resistance and moisture resistance; the lower dielectric plate is placed between the lower electrode and the bottom of the powder washing equipment, and is packaged as a whole with the lower electrode to achieve insulation barrier of the lower electrode, prevent breakdown discharge, and improve the stability of the discharge process; the material of the lower dielectric plate is selected from materials with strong moisture resistance, high dielectric strength and good structural stability.

5. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The bracket is used to stably install the upper electrode and the upper dielectric plate of the plasma generator and position them above the powder washing equipment; insulating rods (8) are provided at both ends of the bracket, the insulating rods are connected to the powder washing equipment, and the vertical distance between the upper electrode and the water body in the powder washing equipment is adjusted by an electric lifting device or a driving device, thereby optimizing the plasma action area and treatment effect.

6. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The plasma equipment further comprises a box (9), wherein the atmospheric pressure dielectric barrier discharge low-temperature plasma generator and the bracket are placed inside the box, and the high-voltage power supply is placed on the box bottom frame; the box is made of stainless steel material and has good structural strength, corrosion resistance and waterproof performance; the front of the box is provided with a shielding door, and the shielding door has an observation window made of organic glass or polycarbonate material for monitoring the plasma discharge state; The inner wall of the box is covered with a polytetrafluoroethylene or ceramic insulation layer to improve electrical insulation and safety during the discharge process; the box is provided with ventilation holes, which are equipped with safety grilles and filters to ensure air circulation and prevent external particles from entering the equipment.

7. A system for reducing bacteria and preserving fresh wet rice noodles according to claim 1, characterized in that: The intelligent control device is integrated and installed on the side shell of the powder washing equipment, including a PLC system and a touch-screen LCD connected to the system, and is used to control the atmospheric pressure dielectric barrier discharge low-temperature plasma generator, the high-voltage power supply, the fresh wet rice noodle conveyor belt in the powder washing equipment, and the plasma upper electrode lifting control device; the PLC system is also used to monitor the operating parameters of the plasma system in real time, and adjust the output voltage and frequency of the high-voltage power supply according to changes in the water conductivity, temperature, water volume and rice noodle load in the powder washing equipment to adapt to different operating loads and ensure the stability of plasma discharge and the consistency of sterilization effect; at the same time, the PLC system can be connected to the host computer of the production line equipment to achieve real-time monitoring of the production process.

8. A method for reducing bacteria and preserving fresh wet rice noodles, characterized in that: The following steps are involved: (1) In the production process of fresh wet rice noodles, rice is sequentially fermented, refined, steamed, extruded, boiled, and other processes before entering the rice noodle washing process. At this stage, the fresh wet rice noodles enter the fresh wet rice noodle sterilization and preservation system according to any one of claims 1 to 7. While the fresh wet rice noodles are being washed by the rice noodle washing device, the plasma device is simultaneously turned on and the processing parameters are set. (2) Fresh wet rice noodles pass through the washing equipment and enter the next production link.

9. A method for reducing bacteria and preserving fresh wet rice noodles according to claim 8, characterized in that: The parameters of the system for reducing bacteria and preserving fresh wet rice noodles are as follows: the gas source is air, the voltage is 30-160 kV, the discharge gap is 10-90 mm, the discharge time interval is 10-30 s, and the discharge time is 1-5 min.

10. A method for reducing bacteria and preserving fresh wet rice noodles according to claim 9, characterized in that: The parameters of the system for reducing bacteria and preserving fresh wet rice noodles are as follows: the gas source is air, the voltage is 60-120 kV, the discharge gap is 30-60 mm, the discharge time interval is 10-30 s, and the discharge time is 5 min.

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