Biochemistry

Esters of butyric acid have a pleasant aroma. They are used as aromatic substances in the confectionery and perfumery industries and in the manufacture of fruit drinks. Propionic fermentation - is the transformation of sugar or lactic acid and its salts with the participation of propionic acid bacteria into propionic and acetic acids with the release of CO 2 and H 2 O. The overall reaction equation is the following: 3C 6 H 12 O 6 -> 4CH 3 - CH 2 - COOH + 2CH 3 - COOH +2CO 2 + 8ATP glucose propionic acid acetic acid ЗСНзСНОНСООН -> 2СН3СЩСООН + CH3COOH + CO 2 + H 2 O lactic acid propionic acid acetic acid This type of fermentation is one of the most important processes during the ripening of rennet cheeses. The release of carbon dioxide produced during this process causes the appearance of cheese “ holes ” - voids. The presence of propionic and acetic acids in the cheese determines its peculiar sharp taste and smell. Propionic acid and its salts serve as inhibitors of filamentous fungi and can be used to prevent the molding of products. Mixed acid fermentationoccwrs with the participation of several types of microorganisms (lactic acid bacteria, acetic acid bacteria, etc.), while acids (lactic, acetic, formic, succinic), ethanol, glycerol, CO 2 , acetone and its derivatives are- formed from glucose. This type of fermentation adversely affects the production of many products. For example, volatile acetic acid, which is one of its main substances, impairs the quality of tinctures. CONTROL QUESTIONS AND TASKS: 1. How the digestion of carbohydrates is processed in the human digestive tract? 2. How the sugar content is regulated in the human blood? 3. Describe the processes of glycogen biosynthesis. 4. What is the essence of glycolysis (anaerobic glucose oxidation)? 5. Write the glycolysis reactions. 6. Write the reaction of oxidative decarboxylation of pyruvic acid. 7. Write the reactions of the Krebs cycle. 8. What is the energy efficiency of the Krebs cycle? 9. What types of fermentation is the basis for lactic acid products, fermentation of vegetables, production of bread and bakery products, wines, tea? Describe the chemical reactions of various types of fermentation. 240