Biochemistry

nature, phytoalexins are cyclic low molecular weight substances, most of the aromatic series, and are polyphenols. Legumes are the most studied phytoalexins. Another type of protection is due to the formation of antibiotic substances in plants before the action of pathogenic factors. Such compounds are called volatile. They, like phytoalexins, are low molecular weight substances, many of which are very unstable. A diverse group of substances, including the glycoalkaloid solanine, has a phytoncidal effect. It is localized mainly in the peel of the potato and accumulates in the light and with the "awakening df the eyes." This substance is toxic to humans, so you should carefully remove the sprouts, "eyes", peel and cook tubers until cooked, because heat treatment destroys a significant part of solanine. When harvesting and transporting vegetables and fruits can be subjected to mechanical damage , while microflora develops intensively • on the surface. However, the plant organism, under favorable conditions of temperature, humidity, aeration, can “ heal ” its wounds, forming a new tissue that protects against infection in other tissues. In the damage zone, intense synthesis processes occur, accompanied by the expenditure of energy, and, consequently, increased respiration. In order to provide plant tissues with sufficient oxygen, ventilation is used in the premises in which vegetables and fruits are stored. Although there is enough oxygen in storage, it cannot always penetrate deep into the tissue; the movement of air flow created during ventilation contributes to this. In addition to the plastic substances from which the integumentary protective tissue is built, phenols and a number of other biologically active compounds are formed in the affected area. Creating favorable conditions for maintaining the necessary level of biochemical processes in the plant organism, it is possible to ensure their protective reactions and maintain nutritional value. The food industry makes extensive use of canning products. It is based on the creation of adverse conditions for the life of microorganisms. To this end, methods are used, which lead to protein denaturation (heating) or administered substance providing high osmotic pressure (greater concentration of sugar or salt) which causes dehydration microorganisms and drying. They also use factors that inhibit the activity of microbial enzymes (antibiotics, volatile) , or create an environment unfavorable for the development of putrefactive microbes (fermentation) . Biochemical methods of conservation are fermentation of vegetables, fruit soaking. These processes are based on the ability of lactic acid microorganisms to form lactic acid from carbohydrates. Under the influence of yeast enzymes, carbohydrates are broken down into ethanol and CO 2 , which loosens the product. As a result, the accessibility of a number of organic compounds for the action of human digestive enzymes is improved . 303