Theory of enzyme inactivation in fresh-keeping pac

Enzyme passivation theory of fresh material fresh-keeping packaging

enzyme passivation theory can be expressed as: the shelf life of fresh material in fresh-keeping packaging depends on the role of biological enzymes. Different biological enzymes can be added to restrict the enzyme activity of the fresh substances to be preserved, and the enzymes in the fresh substances can be inactivated by physical or chemical methods, so as to prolong the life of the fresh substances

fresh substances (agricultural products, etc.) deteriorate. Then Xin Guang of Jinan experimental machine factory shared with you the two steps of structural optimization of spring experimental machine. The root cause of decay is the role of biological enzymes. Therefore, the improvement of fresh-keeping packaging effect of fresh substances can be achieved by adjusting biological enzymes. The key of fresh-keeping packaging technology of fresh substances is to add special enzymes to limit their activity and slow down their biological reaction speed according to the types and characteristics of enzymes of fresh substances, and finally achieve the purpose of fresh-keeping. The key to the application of enzyme passivation theory is to study and determine the types of enzymes produced in fresh substances during storage, and select the biological enzymes that can inhibit the activities of these enzymes according to the characteristics of these enzymes. Restriction or inhibition of enzyme activity is called enzyme passivation. In addition to adding special enzymes, the passivation of enzymes can also be achieved by physical or chemical methods. How to inactivate the enzyme of fresh substances (fresh-keeping agricultural products) and find the relationship between enzyme passivation and shelf life of fresh substances and the change law are the key to the application of enzyme passivation theory in fresh-keeping packaging. Now there are special enzyme products for selection

the theory of enzyme inactivation in fresh-keeping packaging of agricultural products is based on biochemistry. Biochemical studies have shown that enzymes are catalytic proteins produced by living cells, and enzymes play an important role in the activities of living bodies

fresh substances are composed of living bodies. Thousands of chemical reactions are carried out in living bodies all the time, and almost every chemical reaction is carried out smoothly and rapidly under the catalysis of corresponding enzymes. In fact, he said, it is the sum of these chemical reactions that reflects the characteristics of life and the phenomenon of life. Enzyme is a kind of protein, so as long as the fresh material containing protein will have enzyme. Polysaccharides in organic molecules are hydrolyzed into monosaccharides by enzyme catalysis, and then oxidized to provide energy to living bodies

the most important and basic feature of life is metabolism. The metabolic process is composed of countless complex chemical reactions, which are almost all carried out in an orderly manner at a high speed and in an obvious direction under the catalysis of enzymes, so as to maintain the normal life activities such as the growth, development and movement of life

enzymes are catalysts produced by organisms and have the characteristics of general catalysts. In the case of relatively low concentration, it can only affect the speed of chemical reaction without affecting the equilibrium point of chemical reaction, and it is not consumed in the reaction itself. That is to say, when participating in the physicochemical reaction in the fresh-keeping packaging, if it is not fresh-keeping, it needs to obtain some characteristics that can represent its content from the page source file - the internal absorption of keyword items, which is only an intermediate product that acts as a bridge. Enzymes have their own unique catalytic properties, which are different from general catalysts in the following four aspects

the catalytic efficiency of enzymes is generally 106 -1013 times that of inorganic catalysts. In fresh substances, although the contents of various enzymes in biological cells are very low, they still catalyze a large number of substrates (the substances acted by enzymes are called substrates) to react. For example, the ability of salivary amylase to hydrolyze starch can still be observed after it is diluted 1million times

enzyme has strict selectivity for its effect. At present, there are different smog weather substances in major cities. An enzyme can only catalyze some or some substance. For example, amylase can only catalyze the hydrolysis of starch, protease can only catalyze the hydrolysis of protein, sucrase can only catalyze the hydrolysis of sucrose, etc. However, inorganic h+ can catalyze the hydrolysis of starch, fat, protein and sucrose. The complex metabolic process in the organism contains many chemical reactions, which are the result of the participation of many enzymes, thus forming various catalytic systems to ensure the regular metabolism of substances inside and outside the cell. In fresh-keeping packaging, different substances have to have different enzymes involved

because the main component of the enzyme is protein, it is very sensitive to the surrounding environment. It is not resistant to high temperature, and will lose its activity in the presence of strong acids, strong bases, heavy metal salts or ultraviolet light, so enzyme catalyzed reactions are generally carried out under relatively mild conditions. When enzyme preparations are directly used in the industrial field, they show poor stability, low efficiency, and can not react in organic solvents

enzyme can be found by studying the active center of the enzyme and the substrate specificity of the enzyme. The special catalytic function of an enzyme is limited to a small region of its macromolecules, which is called the active center. Specifically, the active center of an enzyme refers to the side chain group of the enzyme molecule that directly participates in the reaction. For simple protein enzymes, the active center is composed of a few amino acid residues in the enzyme molecule or some groups on these residues. Their positions in the primary structure may be far away, that is, they may be located in different positions of the same peptide chain or different peptide chains respectively. However, due to the winding or folding of peptide chains, they are very close in spatial conformation and form a specific active structure. Therefore, the active center is a small region. As for the enzymes that bind proteins, in addition to the participation of certain amino acid residues in the active center, coenzyme molecules or some part of the structure on coenzyme molecules are also important components of the active center. According to its function, the enzyme active center can be divided into substrate binding site and catalytic site, that is to say, the active center is composed of substrate binding site and catalytic site. The two parts have their own division of labor, and the combination of enzyme and substrate is completed by the binding site. Only after the substrate and the enzyme combine into a complex, the group at the catalytic site can complete the catalytic task in the reaction. Although the functions of substrate binding site and catalytic site are different, they are not independent in the active center, but interconnected as a whole. Although most structures in enzyme molecules cannot directly participate in catalysis, it is indispensable to maintain the spatial conformation of the active center and make it play its catalytic activity. Once the complete conformation is destroyed by external physical and chemical factors, the specific conformation of the active center will be difficult to maintain, and the result will affect the activity of the enzyme

substrate specificity of enzymes is also called specificity, which means that enzymes have strict selection of acting (catalytic) substances, including the selection of structure and stereoisomerism. This is the key to whether enzyme preparation can play a role in fresh-keeping packaging. Different enzymes have different requirements for the specificity of the substrate structure. Some enzymes only have requirements for the bond of the substrate structure, regardless of the nature of the groups connected at both ends of the bond. For example, esterase can catalyze the hydrolysis of any ester. Some enzymes also have certain requirements for the group connected to one end of the bond. For example, a - glucosidase can catalyze the hydrolysis of all kinds of glucose, which is the reason why it has requirements for the glucose group at one end of the glycosidic bond and has no requirements for the ligand. Some enzymes can only catalyze one substrate for one chemical reaction. For example, urease can only catalyze the chemical reaction of urea hydrolysis into ammonia and carbon dioxide

almost all enzymes have high specificity for stereoisomers. For example, L-lactate dehydrogenase only catalyzes the dehydrogenation of L-lactate, but has no catalytic effect on D-lactate

reprinted from: China Packaging News