Application and development of microwave technology in food industry

　　Microwave is an electromagnetic wave of high frequency, the frequency range of 300MHz-300GMHz. microwave technology is radio technology in the mid century, it is widely used in radio communication, radio, television, navigation, remote sensing, telemetry, radar and other fields. In recent years, it is a kind of energy has been widely used in the economic construction and people"s daily life, such as household microwave oven has already entered thousands of households. As a means of industrial processing, it first in the food industry has been applied, mainly used for sterilization, drying, baking, cooking, puffing temperature, thawing, aging, and ripening, effectively promoted the development of the food industry. With the development of science and technology, microwave technology will be more widely used in the food industry.

　　Microwave heating mechanism

　　Microwave has a certain energy (electromagnetic energy). Under certain conditions, it can be used as an energy source. The effect of microwave on the material physical, chemical, biological and other effects, can be used for various purposes, but is the most widely used microwave heating, this paper mainly introduces this point.

　　Microwave heating is of extremely high frequency electromagnetic vibration material molecules have polarity, the molecular alignment of dramatic changes, which is similar to the fierce "friction" effect, so that the material becomes hot. This process is the microwave electromagnetic energy into heat energy. Water molecules are polar molecules, strong microwave absorption. Water containing materials under microwave radiation is strong enough, the water molecules in the microwave absorbing materials can be quickly heated evaporation, dry quickly.

　　Microwave sterilization is the common effect of thermal effect and biological effect of microwave. The results show that the thermal effects of microwave on bacteria is protein denaturation, make the bacteria lose nutrition, reproduction and survival conditions and death; biological effects of microwave field changes in cell membrane potential distribution section, effects of cells around the electron and ion concentration, permeability and change the cell membrane of bacteria, therefore malnutrition, not normal bacterial structure disorders, The new supersedes the old., growth inhibition and death. In addition, the normal growth and reproduction of bacterial nucleic acid determines the genetic stability (RNA) and deoxyribonucleic acid (DNA) is composed of a plurality of hydrogen bonding closely together the curl shaped macromolecules. The microwave field is enough strong hydrogen bonding can lead to relaxation, fracture and recombination, which induce genetic mutation or chromosomal aberration, and even rupture. Microwave sterilization is the use of electromagnetic heating Biological effects and biological effects of destruction, therefore, microwave sterilization temperature is lower than the conventional method, only 70-105 degrees, only about 3-5 minutes

　　Two, microwave heating characteristics

　　1, rapid heating, even without heat conduction process, it can instantly penetrate the material is heated, the penetration depth of up to several centimeters, or even more than 10 cm, the number of seconds to tens of seconds will be able to change the microwave energy into heat. The microwave selective heating, the heating is more uniform.

　　2, energy saving and high efficiency: because of the moisture content of the material is easy to absorb microwave and heat, therefore, in addition to a small amount of transmission loss almost no other loss. Microwave heating compared with far infrared heating, energy saving 1/3.

　　3: sterilization preservation: microwave heating with thermal effects and biological effects, therefore, in low temperature quenching mold and sterilization; can maximally preserve the material activity and vitamins in foods, color and nutrients.

　　4, advanced technology, continuous production: as long as the control of microwave power can be achieved heating or termination. It has a perfect delivery system to ensure continuous production, computer control, labor saving

　　5, safe: because the microwave energy is control work in the metal heating chamber and the waveguide, so microwave is effectively controlled. No radiation hazard and harmful gas emissions, does not produce heat, can not pollute the food, does not pollute the environment. To improve the working conditions.

　　6, the equipment covers a small area, saving investment

　　Three, the application of microwave energy technology in food industry

　　As an energy source, microwave has been used in food processing, and it has been used in the food industry

　　1. Is a microwave drying can be widely applied in the field. As for dry noodles, spices, additives, vegetables, mushrooms, meat and so on. The development of microwave drying, 915MHz, through 60KW surface dryer per hour processing macaroni 4000 pounds, while the bacterial content is only the original 1/15, the compared with the traditional hot air drying energy-saving 25%. Japan using 915MHz, 25KW and 2450MHz, 10KW microwave equipment can also be used for drying Chinese instant noodles, potato chips, onion slice processing. The color of the product, taste, taste better than the traditional method. The microwave drying to moisture content below 20% of the best material effect, compared with the traditional method of heating and drying speed much faster, energy saving.

　　2, the traditional method of microwave sterilization sterilization sterilization. Compared with fast speed, low temperature, high efficiency, can penetrate the packaging (bags, bottles) sterilization in order to avoid the two pollution and other advantages. The Swedish 2450MHz, microwave sterilization 80KW bread mold machine, for 4400 pounds per hour processing bread production line. After microwave treatment, the bread temperature increased from 20 C to 80 C, time is only 1-2 minutes, after the bread preservation period from 3-4 days to 30-60 days.

　　Using 2450MHz, 10KW tunnel type microwave drying machine to produce natural pollen, to achieve a continuous production, production efficiency increased by more than ten times, saving more than 80%, good product quality and economic benefits

Needs to be emphasized is that microwave drying in food processing, sterilization, often at the same time, also in the food drying at the same time of sterilization, the microwave equipment "a machine with two", can reduce processing equipment, reduce investment.

　　3, the baking of food materials. The microwave heating temperature above 120 degrees Celsius can produce baking effect. Such as Nestle company with 2450MHz, 10KW microwave equipment can make the baking processing time is only 5-10 minutes, than the traditional baking speed one times more hours, processing capacity of up to 120 kg. Microwave baking equipment "a few years ago has been the customer with our manufacturing peanuts", South milk produced more crispy peanuts, than the traditional method for the production of peanut fragrance, delicious, its products are exported to North America and other places.

　　4, an expanded. The characteristics of microwave heating is almost the same material inside and outside heat, which is conducive to the rapid vaporization and internal moisture migration, the formation of numerous micro channel, the structure was loose. As long as the choice of appropriate raw materials and technology, can obtain good expansion effect. Such as microwave equipment for our production for a aquatic products (dry goods) expanded, compared with the original traditional expansion method is fast, high quality.

　　5. Temperature is the temperature thawing frozen solid food temperature rises to "freezing point", such as -1 to -2 DEG C. The traditional method is the natural thawing or slow thawing soaking in water, need ten hours, or even days. But the microwave temperature without opening the product packaging, can be completed in a few minutes, greatly save time, material without loss of quality, space around the traditional 1/10 technology, reduce complexity and bacterial contamination of production, labor efficiency is very high.

　　6, aging aging. Promote bio chemical reaction within the food material by microwave heating, so it can be used to promote wine, fermented condiment products such as "aging". Such as microwave to white heat, aging, eliminate its spicy, make liquor more soft, soft, soft, smooth and suitable. Microwave heating treatment of wine wine storage can be equivalent to 3-6 months, which can shorten the wine storage period, accelerate the capital turnover.

　　Four, microwave energy technology to promote the development of the food industry

　　The application of microwave energy technology in food processing, not limited to drying, sterilization, improve product quality; a new powerful technique for developing new products. With the transformation and microwave technology to replace the traditional processing methods for the development of new products, the production of the roads had been widened. Such as oil fried food, because it may contain small amounts of carcinogenic substances not to declare the "green food", and used to replace the traditional microwave processing of food (fried instant noodles without oil, microwave puffed food) no carcinogenic worries. And as the dry production of dehydrated vegetables frozen with high quality, but the high cost and the product is expensive, ordinary people can not afford. Domestic dehydrated vegetables the production is mainly used in hot air drying, and the fixing treatment with 80-90 degrees of hot water blanching, the loss of nutrients. Microwave and hot air drying combined with our first new approach to the production of dehydrated vegetables, the product quality is close to Lyophilization, cost is greatly reduced. Extraction method of microwave extraction as compared with the traditional high extraction efficiency, time is only one of the few original methods to reduce energy consumption, and waste solvent production, the equipment investment is only extracted by supercritical carbon dioxide method 1/ 4

　　Five, China"s microwave energy application technology to flourish

　　China in the last century in 70s from the developed countries the application of microwave energy technology, the Ministry of electronics industry in Nanjing electronic tube factory (772 factory) set up a microwave energy application station, began to conduct research and application promotion. Through the efforts of the microwave and these years of development, China has at least a dozen microwave application excellent professional equipment manufacturers. The manufacturers of the products can be compared with the developed countries, especially the equipment price is much higher than similar foreign equipment, with strong competitiveness in the international market, and the device has the microwave equipment exports.

　　Six. Conclusion

　　The microwave energy application in food industry to improve product quality, reduce production cost, improve working conditions, improve the production efficiency and economic benefit, the transformation of traditional processing technology, the development of new products have made remarkable achievements. Application Research of the microwave can devote more and more scientific and technical personnel, with more and more food the enterprise can and will be using microwave technology. It can be expected that the microwave technology in food industry more widely, will further improve China"s food industry equipment and technical level, while the domestic microwave energy technology and equipment manufacturers are constantly improving, in order to meet the growing needs of the food industry.