Microwave extraction technology

Microwave extraction technology is a new technology for the extraction of effective ingredients in food and traditional Chinese medicine. The article on the application of microwave technology to the extraction of organic compounds in the world was published in 1986. Some foreign experts found that it only takes a few minutes to extract the target substances that need several hours or even more than ten hours for traditional heating by placing the samples in the ordinary household microwave oven. Through more than ten years of efforts and development, microwave extraction technology has been applied to spices, condiments, natural pigments, Chinese herbal medicine, cosmetics, soil analysis and other fields.
1. Microwave extraction mechanism
Microwave extraction is that high-frequency electromagnetic wave penetrates the extraction medium and reaches the inside of the extracted material. Microwave energy can be rapidly converted into heat energy to make the internal temperature of the cell rise rapidly. When the internal pressure of the cell exceeds the bearing capacity of the cell wall, the cell breaks, and the effective components in the cell flow out freely. The extracted material is obtained by dissolving in the extraction medium at a lower temperature and further filtering and separation. Under the action of microwave radiation, the components of the extracted material will accelerate the diffusion to the interface of the extraction solvent, thus increasing the extraction rate several times, reducing the extraction temperature and improving the extraction quality.
2. Advantages of microwave extraction
Traditional thermal extraction is carried out from the outside to the inside by means of heat conduction and thermal radiation, while microwave extraction is carried out by heating the material inside and outside at the same time. Compared with traditional thermal extraction, the main advantages of microwave extraction are:
A. High quality, which can effectively protect the functional components in food, medicine and other chemical materials;
B. High extraction rate;
C. High selectivity for extracts;
D. Fast and time-saving, which can save more than 50% - 90% of the time;
E. Less solvent consumption (more than 50% - 90% less than conventional methods);
F. Safe, energy-saving, pollution-free, simple production equipment and investment saving.
3. Comparison between microwave extraction and other extraction methods
Microwave extraction has high efficiency, low energy consumption and low operating cost, which meets the requirements of environmental protection. It can be widely used in Chinese herbal medicine, spices, health food, food, cosmetics, tea drinks, condiments, pectin, high-viscosity chitosan and other industries. At present, microwave extraction has been used in many Chinese herbal medicine extraction production lines in China, such as pueraria lobata, tea, gingko, etc. Microwave extraction has been listed as one of the modern promotion technologies of food processing and traditional Chinese medicine in the 21st century. The scientific research workers of a Chinese medicine research institute have treated hundreds of Chinese medicines by microwave extraction. Both extraction speed, extraction efficiency and extraction quality are much better than the conventional process. Microwave extraction technology has obvious advantages over other existing extraction technologies. The chemical solvent extraction method consumes a lot of energy and materials, takes a long time, has a low extraction efficiency and a large amount of industrial pollution. Supercritical fluid extraction has greatly improved the extraction efficiency, but the required equipment is complex, the solvent selection range is narrow, high pressure vessels and high pressure pumps are required, and it is difficult and costly to establish a large-scale extraction production line.
Comparison between traditional methods and microwave extraction

Microwave extraction process flow:
Material selection - cleaning - crushing - microwave extraction - separation - concentration - drying - pulverization - product
4. Overview of microwave extraction equipment
The equipment used for microwave extraction is roughly divided into two categories: one is microwave extraction tank, and the other is continuous microwave extraction line. One of the main differences between the two is that the materials are processed in batches, similar to the multi-function extraction tank; The other is the extraction equipment that works in a continuous manner. Specific parameters are generally designed by the manufacturer according to user requirements