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Non- thermal effects of microwave sterilization mechanism
Non- thermal effects of microwave sterilization mechanism
Many studies show that microwave heating as compared with the general method of sterilization , at a temperature or shorten the time of death of bacteria under the same conditions lethal sterilization temperature. This fact is not only theory to explain the thermal death . 01Mn , who reveals the microwave Fusarium spores of non-thermal effects. They pointed out . More susceptible to microbes in the microwave field than any other medium microwave effect , therefore, proposed the theory of non- thermal effects of microwave sterilization mechanism . 1970 , Gmy method using a combination microwave and steam sterilization . And combination microwave and infrared sterilization wears two patented technologies , confirmed the existence of non-thermal sterilization effects. In 1994,王绍林to strong heat resistance of bacteria Bacillus subtilis bubble bud , were killed Yin and microwave heating test compared to the traditional . Get two kinds of heat treatment of bacterial death rate curve. Then the degree of difference from the point of view of physics, microwave and conventional sterilization between the cause of death and thus strong evidence of non-thermal effects of microwave sterilization mechanism . On this basis , researchers who have carried out similar studies , there have been different interpretations of the model .
1 . From the biological point of view to explain the physics of non-thermal microwave sterilization mechanism is easier for most people to accept , its main models include :
( 1 ) ion channels interpretation model . According to this theory, the cells with the outside world and conducted a series of complex biochemical processes rely on the cell membrane potential difference ( about o.03-0.10 v) control , ie changes in membrane potential can activate ( open ) or closed channel with the outside world . Bacteria in such a high frequency electric field strength and strong microwave field , the membrane potential is likely to change its normal physiological function will change the activities that endanger the survival of the bacteria.
( 2 ) protein denaturation interpretation model . The theory suggests . The microbial proteins, nucleic acids and water and other polar molecules. These polar molecules at high frequency , a strong electric field strength in the microwave field with the polarity of the microwave field is changing rapidly and cause rotation of the protein molecules and other sharp reciprocating vibration, on the one hand into mutual frictional heat and its temperature , other damage caused by chemical bonds denaturation of protein molecules , and thus undermine the normal physiological activity of microbial function , so as to achieve the purpose of sterilization .
( 3 ) changes in vivo bovine electromagnetic reaction equilibrium theory to explain . Researchers think the theory holds , non-thermal effects of electromagnetic waves on the chemical reactions of the organism resulted in "non- thermal effects ." According to this argument, the activation energy of a chemical reaction changes the electromagnetic wave and pre-exponential factor , making the anti- government if the current acceleration and deceleration of two results . Because life is a dynamic process is actually the process of metabolic balance , always occurs with metabolic ( biochemical reactions ) . Thus, the effect of electromagnetic changes in the biochemical process, the reaction rate and the equilibrium constant , resulting in such a dynamic balance during metabolic disorder . Damage to the organism 's life . Metabolic energy does not come from non-thermal effects of electromagnetic waves but from the organism ( such as ATP synthesis and decomposition ) .
2 from the energy point of view, although microwave energy can not destroy the quantum vivo covalent bond, but hydrogen bonding, van der Waals forces , hydrophobic interactions, and so on which maintain salt bond secondary hinge nucleic acids, proteins and other biological macromolecules of high-level structure t has a role in the destruction of these secondary keys are maintained nucleic acid, protein conformation , the force of the biofilm structure . These secondary keys once destroyed . Would jeopardize the spatial structure of biological macromolecules , affecting its normal physiological function .
3 . From a biological point of cell analysis , microwave microorganisms ( bacteria , for example) also have biological effects. ① is the main component of the bacterial cell wall is not a cellulose, but the peptidoglycan (N acetylglucosamine and Discussion - acetyl muramic acid by l, 4 linkage from sugar Xi ). Especially within the cell wall of Gram-negative Yin protein content is higher, in the microwave field , the occurrence of mechanical damage cell walls , make cytoplasm leakage. Affect their normal physiological activities. ⑦ bacterial cell is a selective semipermeable membrane lipids and proteins from the fat composition , which is a bacterial cell sites substances with the environment , energy and information exchange. Inside and outside the bacterial cell concentration gradients exist , if the cell is a high K ', low Na', the external environment is a high Nat, low K ', these ion gradients are distributed on the cell membrane Nat, K' pump against a concentration gradient to maintain active transport of ions other AIb2 ', there are significant intracellular ion concentration gradients within c42' pump to maintain. These creatures do not Li ion pump at high microwave field. Will not be able to play its normal physiological function . Cell ion channels in accordance with the doctrine of the cells with the outside world series of complex physiological processes inside and outside the cell membrane potential difference is to rely on control , that changes in membrane potential can activate ( open ) or channel Jane off contact with the outside world , if the normal cell membrane potential the destruction of the state , is bound to affect its normal physiological activities , resulting in dangerous knives survival of bacteria. ② intracellular bacterial enzyme , at high frequencies , a strong electric field intensity of the microwave field , its function may or inactivation disorder , especially those with metal ions to metallic enzyme cofactors in the microwave field, the gold ions with environment Department may change , affecting the activity of these enzymes . No nuclear membrane nucleus ④ Lee bacterial cells , only the proposed nuclear cooperation area. Nucleoid region in which the carrier of the genetic material - the exposed annular chromosome DNA, little or no protein binding capacity of the group , the double helix structure of DNA in A = D , c = c hydrogen bonding between base pairs microwave susceptible to impact and damage.
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