Principle of Microwave Sterilization Machine：
Principle of microwave sterilization: Microwave sterilization is an extension of microwave heating technology. It shows that the changes and reactions of cell physiological activities of organism after the interaction between microwave and organism and its basic unit-cell. Compared with pasteurization, microwave sterilization has the following remarkable characteristics.Microwave sterilization is a physical sterilization method. It can kill bacteria, fungi, insect eggs, viruses and other harmful microorganisms without adding chemical preservatives. In the process of killing harmful microorganisms, it will not pollute food residues or radioactive substances and is safe and harmless. It will not change the color, aroma and nutrition of food.At the same sterilization temperature, the sterilization time is short and no preheating is needed. For example, the killing time of E. coli is about 30S. Under the same sterilization conditions, the temperature of bacterial death is relatively low, and the sterilization effect is very significant. Because of the simultaneous sterilization of different parts of the material, the sterilization time is short, which can avoid the influence of long-term heating on food quality, especially for foods that are not suitable for sterilization at higher temperature or longer heating time. For example: ginger powder with volatile spices, fresh and tender jellyfish with more water content, etc. Microwave sterilization can achieve the best results for materials that need sterilization as well as quality requirements such as color, fragrance and taste unchanged. Microwave sterilization can be divided into post-packaging sterilization and pre-packaging sterilization. Packaging containers can not be made of metal materials, medium materials are needed, generally plastic soft packaging or glass, engineering plastic containers are appropriate. In order to prevent bag swelling in microwave sterilization process, the equipment can apply pressure in the working bin to adopt back pressure sterilization process, which can prevent bag swelling loss.
For the mechanism of microwave sterilization, the research mainly focuses on the thermal and non-thermal effects.
The Food contains a variety of polar molecules. When microwave irradiation occurs, they move in the alternating electric field generated by microwave irradiation. The friction between the molecules generates heat. As a result, the temperature rises and the biological macromolecules such as proteins become denatured and inactivated, which makes the microorganism dead or disturbed and unable to reproduce, so as to achieve the purpose of sterilization. The longer the sterilization time, the higher the temperature, the stronger the killing effect on microorganisms.
The non-thermal effect of microwave, also known as biological effect, refers to the physiological, biochemical and functional changes of cells without obvious temperature changes or sub-lethal temperature. At present, there are several explanations for the mechanism of non-thermal effect. Microwave can change the polarity of proteins, nucleic acids and other molecules in microorganisms, causing the rotation and vibration of molecular groups, thus denaturing and sterilizing proteins.Microwave can damage the cell wall of microorganism, leakage of cytoplasm and affect its normal physiological activities. Under the alternating electric field produced by microwave, the concentration of ions and electrons inside and outside the cell membrane of microorganism changes, the potential difference is disordered, the permeability of cell membrane is changed, various enzymes in cell are inactivated, and the normal metabolism is destroyed.
Characteristics of Precooked Starch Microwave Sterilization Machine:
Microwave sterilization dryer is uniform and fast. While sterilizing, the device retains the original taste, appearance and color of the pastry. Heating, drying and sterilizing are multi-purpose, environmentally friendly and efficient, saving more than 30% of electricity than traditional heating methods. Safety and hygiene to improve production environment. Microwave equipment has no waste heat radiation, no dust, no noise, no pollution, and is easy to achieve the detection standard of food hygiene. Easy to use and operate. Microwave power and belt speed can be steplessly adjusted. There is no thermal inertia. It can be switched on and off immediately. The operation is simple and the size can be designed.
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