Biochemistry

processes are kept at a low level necessary to preserve the composition of fruits and vegetables, as well as their resistance to infection. To reduce the intensity of respiration, nitrogen or carbon monoxide is introduced into the gaseous environment where plant products are stored. Water is an obligatory participant in most reactions in living organisms; therefore, humidity of the environment is important for food storage. Its decrease causes inhibition of the action of enzymes and prolongs shelf life. The lowest respiration rate in plants is observed during the dormant period , which is a natural physiological state after maturation. The rest period is an important adaptation to adverse conditions. It is associated with the presence of certain chemicals in plants, in particular polyphenols, which inhibit growth. The mechanism of their action is manifested in the uncoupling of the processes of oxidation and phosphorylation, i.e., the cessation of energy storage in macroergic ATP bonds. As a result, cells are not provided with that efficient type of energy that can be used for the growth process. Inhibition of growth stimulants that are contained in plant tissues (for example, indolylacetic acid, ethylene, etc.) gives a similar result. Fats are very unstable during storage. They are oxidized by cellular enzymes. The presence of lipase etc. ivodit hydrolysis of triacylglycerols and the accumulation of free unsaturated fatty acids, which are rapidly oxidized by oxygen. This process is stimulated by various factors and especially the enzyme lipoxygenase. As a result, peroxides, epoxy and hydroperoxides are formed, oxidizing fatty acids, as well as carotenoids and other compounds. Antioxidants delay their formation. The natural antioxidant is vitamin E, found in flour and cereal. In order to prevent the action of lipase and lipoxygenase, the feedstock from which flour and cereals are made is steamed. When stored as a result of respiration, vitamins are consumed , especially ascorbic acid. So, potatoes during the winter lose up to 50% of the initial amount of vitamin C. Currently, thanks to the successes of genetics in agriculture, intensive work is being earned out on the cultivation of cultivated plant varieties resistant to the action of pathogens and pests. Among the defense mechanisms, an important role is played by antibiotic substances - phytoalexins, which are produced by higher plants in response to contact with pathogenic factors. Phytoalexins are formed in living cells and accumulate in necrotic tissue areas that died under the action of a pathogenic principle. Thus, dead cells due to the accumulated phytoalexins protect the entire plant from death. The ability to form phytoalexins is programmed in the gene apparatus, but up to a certain point repressed. Removal of repression occurs when inducers appear - substances secreted by a pathogenic agent. By chemical 302