Biochemistry

CHAPTER 15. BIOCHEMICAL PROCESSES IN FOOD RAW MATERIAL DURING STORAGE AND TECHNOLOGICAL PROCESSING Engineer-technologist and commodity expert is important to know the biochemical basis of storage, Perera Botko food, and control over their quality. During the storage of food products , various kinds of changes can occur in them, which is most often the result of the interaction of the components included in their composition . So, the content of carbohydrates and other plastic substances changes significantly during the post-harvest ripening period. In most fruits and vegetables (tomatoes, carrots, etc.), the amount of starch decreases as a result of its enzymatic saccharification, sucrose, protopectin, hemicelluloses, and organic acids become less. So, for example, during the storage of potatoes, both starch is converted into sugar and sugar into starch. Total Content Percentageacids in stored fruits and vegetables decreases, but the amount of some of them may increase, for example, as a result of the conversion of di- and tricarboxylic acids in the Krebs cycle. A decrease in the concentration of pectin substances under storage occurs due to their destruction. As the fruits mature, the decomposition of soluble pectin to polygalacturonic acid and methyl alcohol is observed, which causes tissue loosening. The level of fiber in fruits and vegetables remains almost unchanged, and the amount of polyphenols decreases, which leads to a change in the taste of fruits. During storage, the vitamin C content in fruits decreases, especially during the period of overriding, and the amount of carotenoids increases. “ Live ” products consume oxygen during storage and consume organic substances (mainly carbohydrates). This process is called respiration; it is the main form of interaction between fruits and vegetables with the environment. Its biological role is to provide tissues with the energy necessary for life. The breathing process is complex, it flows through a series of intermediate products involving certain enzymes. With anaerobic respiration , much less energy is released, so fruits and vegetables consume significantly more substrate, which explains the loss of their mass. The aging of the tissues of fruits and vegetables is accompanied by the accumulation of anaerobic decomposition products (alcohol, acetaldehyde, acetic and lactic acids, etc.). The main pathway for the breakdown of carbohydrates during breathing is oxidation through the stage of formation of pyruvic acid , but there are other additional ones, in particular, the pentose phosphate cycle. By controlling the storage temperature and the composition of the gaseous medium, it is possible to achieve minimal loss of nutrients in plant materials. So, at low positive temperatures, the activity of enzymes decreases. This ensures that life 301